Conversion of dried Aspergillus candidus mycelia grown on waste whey to biodiesel by in situ acid transesterification.

PubMed

Kakkad, Hardik; Khot, Mahesh; Zinjarde, Smita; RaviKumar, Ameeta; Ravi Kumar, V; Kulkarni, B D

2015-12-01

This study reports optimization of the transesterification reaction step on dried biomass of an oleaginous fungus Aspergillus candidus grown on agro-dairy waste, whey. Acid catalyzed transesterification was performed and variables affecting esterification, viz., catalyst methanol and chloroform concentrations, temperature, time, and biomass were investigated. Statistical optimization of the transesterification reaction using Plackett-Burman Design showed biomass to be the predominant factor with a 12.5-fold increase in total FAME from 25.6 to 320mg. Studies indicate that the transesterification efficiency in terms of conversion is favored by employing lower biomass loadings. A. candidus exhibited FAME profiles containing desirable saturated (30.2%), monounsaturated (31.5%) and polyunsaturated methyl esters (38.3%). The predicted and experimentally determined biodiesel properties (density, kinematic viscosity, iodine value, cetane number, TAN, water content, total and free glycerol) were in accordance with international (ASTM D6751, EN 14214) and national (IS 15607) standards. Copyright © 2015. Published by Elsevier Ltd.

Biodiesel Production using Heterogeneous Catalyst in CSTR: Sensitivity Analysis and Optimization

NASA Astrophysics Data System (ADS)

Keong, L. S.; Patle, D. S.; Shukor, S. R.; Ahmad, Z.

2016-03-01

Biodiesel as a renewable fuel has emerged as a potential replacement for petroleum-based diesels. Heterogeneous catalyst has become the focus of researches in biodiesel production with the intention to overcome problems associated with homogeneous catalyzed processes. The simulation of heterogeneous catalyzed biodiesel production has not been thoroughly studied. Hence, a simulation of carbon-based solid acid catalyzed biodiesel production from waste oil with high FFA content (50 weight%) was developed in the present work to study the feasibility and potential of the simulated process. The simulated process produces biodiesel through simultaneous transesterification and esterification with the consideration of reaction kinetics. The developed simulation is feasible and capable to produce 2.81kmol/hr of FAME meeting the international standard (EN 14214). Yields of 68.61% and 97.19% are achieved for transesterification and esterification respectively. Sensitivity analyses of FFA composition in waste oil, methanol to oil ratio, reactor pressure and temperature towards FAME yield from both reactions were carried out. Optimization of reactor temperature was done to maximize FAME products.

Design and synthesis of multifunctional poly(ethylene glycol)s using enzymatic catalysis for multivalent cancer drug delivery

NASA Astrophysics Data System (ADS)

Seo, Kwang Su

The objective of this research was to design and synthesize multifunctional poly(ethylene glycol)s (PEG)s using enzyme-catalyzed reactions for multivalent targeted drug delivery. Based on computer simulation for optimum folate binding, a four-arm PEG star topology with Mn = 1000 g/mol was proposed. First, a four-functional core based on tetraethylene glycol (TEG) was designed and synthesized using transesterification and Michael addition reactions in the presence of Candida antarctica lipase B (CALB) as a biocatalyst. The four-functional core (HO)2-TEG-(OH)2 core was successfully prepared by the CALB-catalyzed transesterification of vinyl acrylate (VA) with TEG and then Michael addition of diethanolamine to the resulting TEG diacrylate with/without the use of solvent. The functional PEG arms with fluorescein isothiocyanate (FITC) and folic acid (FA) were prepared using both traditional organic chemistry and enzyme-catalyzed reactions. FITC was reacted with the amine group of H2N-PEG-OH in the presence of triethylamine via nucleophilic addition onto the isothiocyanate group. Then, divinyl adipate (DVA) was transesterified with the FITC-PEG-OH product in the presence of CALB to produce the FITC-PEG vinyl ester that will be attached to the four-functional core via CALC-catalyzed transesterification. For the synthesis of FA-PEG vinyl ester arm, DVA was first reacted with PEG-monobenzyl ether (BzPEG-OH) in bulk in the presence of CALB. The BzPEG vinyl ester was then transesterified with 12-bromo-1-dodecanol in the presence of CALB. Finally, BzPEG-Br was attached to FA exclusively in the gamma position using a new method. The thesis also discusses fundamental studies that were carried out in order to get better understanding of enzyme catalyzed transesterification and Michael addition reactions. First, in an effort to investigate the effects of reagent and enzyme concentrations in transesterification, vinyl methacrylate (VMA) was reacted with 2-(hydroxyethyl) acrylate (2HEA) in the presence of CALB. When the reaction was performed in tetrahydrofuran (THF) with a 2HEA concentration of 0.10 mol/L, only 19% conversion was observed within 4 hours, whereas complete conversion was achieved under solventless conditions. The effect of enzyme concentration in reactions with and without solvent was also studied. The effect of DVA concentration on the CALB-catalyzed transesterification with TEG was studied under solventless conditions. When 1.5 molar equivalent of DVA per OH in TEG was used, 42% divinyl-functionalized product was observed together with 56.5% oligomerized (di-, tri-, tetra- and pentamer) products. At 10 eq. of DVA, only 18.4% oligomerized products were obtained. The effect of diol molecular weight was also investigated. At 10.0 eq. DVA per OH only 2% dimer was observed with PEG Mn=1000 g/mol, and a single divinyl functionalized product was obtained with M n=2000 g/mol. The effects of polymer molecular weight and DVA concentration were also studied in the reaction of DVA with PEG monomethyl ether (MPEG-OH, Mn=1100 g/mol and 2000 g/mol). The extent of coupling decreased from 35% to 0.4% when the DVA concentration was increased from 1.5 to 10 per -OH in the MPEG-OH. No coupling was observed with MPEG-OH Mn=2000 g/mol at 5 eq. DVA per -OH. Following these fundamental studies, TEGs and PEGs were enzymatically functionalized. TEGs were transesterified with VMA and vinyl crotonate in the presence of CALB under solventless conditions within 4 hours of reaction time. Benzyl protected TEG-OHs were also successfully functionalized with VMA and vinyl crotonate in the presence of CALB under solventless conditions within 2 hours. An eight-functional molecule was also synthesized from (HO)2-TEG-(OH) 2. First an alpha-vinyl-o-acrylate linker was prepared by the transesterification of DVA with 2HEA. This linker was then transesterified with (HO)-TEG-(OH)2, followed by Michael addition of DEA to the tetra-acrylated TEG. (Abstract shortened by UMI.)

Highly efficient extraction and lipase-catalyzed transesterification of triglycerides from Chlorella sp. KR-1 for production of biodiesel.

PubMed

Lee, Ok Kyung; Kim, Young Hyun; Na, Jeong-Geol; Oh, You-Kwan; Lee, Eun Yeol

2013-11-01

We developed a method for the highly efficient lipid extraction and lipase-catalyzed transesterification of triglyceride from Chlorella sp. KR-1 using dimethyl carbonate (DMC). Almost all of the total lipids, approximately 38.9% (w/w) of microalgae dry weight, were extracted from the dried microalgae biomass using a DMC and methanol mixture (7:3 (v/v)). The extracted triglycerides were transesterified into fatty acid methyl esters (FAMEs) using Novozyme 435 as the biocatalyst in DMC. Herein, DMC was used as the reaction medium and acyl acceptor. The reaction conditions were optimized and the FAMEs yield was 293.82 mg FAMEs/g biomass in 6 h of reaction time at 60 °C in the presence of 0.2% (v/v) water. Novozyme 435 was reused more than ten times while maintaining relative FAMEs conversion that was greater than 90% of the initial FAMEs conversion. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodiesel production from used cooking oil by two-step heterogeneous catalyzed process.

PubMed

Srilatha, K; Prabhavathi Devi, B L A; Lingaiah, N; Prasad, R B N; Sai Prasad, P S

2012-09-01

The present study demonstrates the production of biodiesel from used cooking oil containing high free fatty acid by a two-step heterogeneously catalyzed process. The free fatty acids were first esterified with methanol using a 25 wt.% TPA/Nb(2)O(5) catalyst followed by transesterification of the oil with methanol over ZnO/Na-Y zeolite catalyst. The catalysts were characterized by XRD, FT-IR, BET surface area and CO(2)-TPD. In the case of transesterification the effect of reaction parameters, such as catalyst concentration, methanol to oil molar ratio and reaction temperature, on the yield of ester were investigated. The catalyst with 20 wt.% ZnO loading on Na-Y exhibited the highest activity among the others. Both the solid acid and base catalysts were found to be reusable for several times indicating their efficacy in the two-step process. Copyright © 2012 Elsevier Ltd. All rights reserved.

Amphiphilic phase-transforming catalysts for transesterification of triglycerides

NASA Astrophysics Data System (ADS)

Nawaratna, Gayan Ivantha

Heterogeneous catalytic reactions that involve immiscible liquid-phase reactants are challenging to conduct due to limitations associated with mass transport. Nevertheless, there are numerous reactions such as esterification, transesterification, etherification, and hydrolysis where two immiscible liquid reactants (such as polar and non-polar liquids) need to be brought into contact with a catalyst. With the intention of alleviating mass transport issues associated with such systems but affording the ability to separate the catalyst once the reaction is complete, the overall goal of this study is geared toward developing a catalyst that has emulsification properties as well as the ability to phase-transfer (from liquid-phase to solid-phase) while the reaction is ongoing and evaluating the effectiveness of such a catalytic process in a practical reaction. To elucidate this concept, the transesterification reaction was selected. Metal-alkoxides that possess acidic and basic properties (to catalyze the reaction), amphiphilic properties (to stabilize the alcohol/oil emulsion) and that can undergo condensation polymerization when heated (to separate as a solid subsequent to the completion of the reaction) were used to test the concept. Studies included elucidating the effect of metal sites and alkoxide sites and their concentration effects on transesterification reaction, effect of various metal alkoxide groups on the phase stability of the reactant system, and kinetic effects of the reaction system. The studies revealed that several transition-metal alkoxides, especially, titanium and yttrium based, responded positively to this reaction system. These alkoxides were able to be added to the reaction medium in liquid phase and were able to stabilize the alcohol/oil system. The alkoxides were selective to the transesterification reaction giving a range of ester yields (depending on the catalyst used). It was also observed that transition-metal alkoxides were able to be recovered in the form of their polymerized counterparts as a result of condensation polymerization subsequent to completion of the transesterification reaction.

The study of CaO and MgO heterogenic nano-catalyst coupling on transesterification reaction efficacy in the production of biodiesel from recycled cooking oil.

PubMed

Tahvildari, Kambiz; Anaraki, Yasaman Naghavi; Fazaeli, Reza; Mirpanji, Sogol; Delrish, Elham

2015-01-01

Fossil fuels' pollution and their non-renewability have motivated the search for alternative fuels. Some common example of seed oils are sunflower oil, date seed oil, soy bean oil. For instance, soy methyl and soy-based biodiesel are the main biodiesel. Biodiesel is a clean diesel fuel that can be produced through transesterification reaction. Recycled cooking oil, on the other hand, is one of the inexpensive, easily available sources for producing biodiesel. This article is aimed at production of biodiesel via trans-esterification method, Nano CaO synthesis using sol-gel method, and Nano MgO synthesis using sol-gel self-combustion. Two catalysts' combination affecting the reaction's efficacy was also discussed. Optimum conditions for the reaction in the presence of Nano CaO are 1.5 % weight fracture, 1:7 alcohol to oil proportion and 6 h in which biodiesel and glycerin (the byproduct) are produced. Moreover, the optimum conditions for this reaction in the presence of Nano CaO and Nano MgO mixture are 3 % weight fracture (0.7 g of Nano CaO and 0.5 g of Nano MgO), 1:7 alcohols to oil proportion and 6 h. Nano MgO is not capable of catalyzing the transesterification by itself, because it has a much weaker basic affinity but when used with Nano CaO due to its surface structure, the basic properties increase and it becomes a proper base for the catalyst so that CaO contact surface increases and transesterification reaction yield significantly increases as well. This study investigates the repeatability of transesterification reaction in the presence of these Nano catalysts as well.

Transesterification of propylene glycol methyl ether in chromatographic reactors using anion exchange resin as a catalyst.

PubMed

Oh, Jungmin; Sreedhar, Balamurali; Donaldson, Megan E; Frank, Timothy C; Schultz, Alfred K; Bommarius, Andreas S; Kawajiri, Yoshiaki

2016-09-30

Reactive chromatography using an anion exchange resin is proposed for a transesterification reaction of propylene glycol methyl ether (DOWANOL™ PM) with ethyl acetate to produce propylene glycol methyl ether acetate (DOWANOL™ PMA). This reaction is studied in batch and chromatographic reactors catalyzed by an anion exchange resin. Several anion exchange resins are tested and compared based on the performance of resin as an adsorbent and a catalyst. A chromatographic column is packed with a selected catalyst, AMBERLITE™ IRA904, and both reaction and chromatographic elution are studied at different temperatures and feed concentrations. The resulting chromatograms are fitted to a mathematical model to obtain adsorption equilibrium and reaction kinetic parameters by the inverse method. Compared to esterification investigated in a previous study, transesterification has advantages such as a higher conversion at lower temperature and easy removal of the byproduct which may lead to higher productivity. Deactivation of anion exchange resins is observed and potential solutions are suggested. Copyright © 2016 Elsevier B.V. All rights reserved.

A review on production of biodiesel using catalyzed transesterification

NASA Astrophysics Data System (ADS)

Dash, Santosh Kumar; Lingfa, Pradip

2017-07-01

Biodiesel is arguably an important fuel for compression ignition engine as far as sustainability and environmental issues are concerned. It can be produced from both edible and non-edible vegetable oils and animal fats. Owing to higher viscosity, the utilization of crude vegetable oil is not advisable as it results engine failure. For reducing the viscosity and improving the other fuel characteristics comparable to that of diesel fuel, different approaches have been developed. However, transesterification process is very reliable, less costly and easy method compared to other methods. Due to more free fatty acids content in most of the non-edible vegetable oils, a pretreatment is employed to convert the acids to ester, then transesterified with suitable alcohol. Primarily yield of biodiesel depends upon the molar ratio of oil/alcohol, reaction temperature, reaction time, amount of catalyst, type of catalyst, stirring speed. Both homogeneous and heterogeneous catalysts are used for synthesis purposes. Heterogeneous catalysts are less costly, environmental benign and can be derived from natural resources. Enzymatic catalysts are more environmental benign than heterogeneous catalysts but are costly, which hinders its widespread research and utilization. This article reviews the results of prominent works and researches in the field of production of biodiesel via catalyzed transesterification process.

Synergism between microwave irradiation and enzyme catalysis in transesterification of ethyl-3-phenylpropanoate with n-butanol.

PubMed

Yadav, Ganapati D; Pawar, Sandip V

2012-04-01

Lipase catalyzed transesterification was investigated to study the synergistic effect of microwave irradiation and enzyme catalysis. Transesterification of ethyl-3-phenylpropanoate with n-butanol was chosen as the model reaction using immobilized enzymes such as Novozyme 435, Lipozyme RMIM and Lipozyme TL IM with microwave irradiation. Novozyme 435 was the best catalyst. The effect of various parameters affecting the conversion and initial rates of transesterification were studied to establish kinetics and mechanism. There is synergism between enzyme catalysis and microwave irradiation. The analysis of initial rate data and progress curve data showed that the reaction obeys the Ping-Pong bi-bi mechanism with inhibition by n-butanol. The theoretical predictions and experimental data match very well. These studies were also extended to other alcohols such as 2-phenyl-1-propanol, n-octanol, benzyl alcohol, iso-amyl alcohol, 2-hexanol and 2-pentanol under otherwise similar conditions. Copyright © 2012. Published by Elsevier Ltd.

Heterogeneous base catalysts for edible palm and non-edible Jatropha-based biodiesel production

PubMed Central

2014-01-01

Background Transesterification catalyzed by solid base catalyst is a brilliant technology for the noble process featuring the fast reaction under mild reacting condition in biodiesel production. Heterogeneous base catalysts are generally more reactive than solid acid catalysts which require extreme operating condition for high conversion and biodiesel yield. In the present study, synthesis of biodiesel was studied by using edible (palm) or non-edible (Jatropha) feedstock catalyzed by heterogeneous base catalysts such as supported alkali metal (NaOH/Al2O3), alkaline-earth metal oxide (MgO, CaO and SrO) and mixed metal oxides catalysts (CaMgO and CaZnO). Results The chemical characteristic, textural properties, basicity profile and leaching test of synthesized catalysts were studied by using X-ray diffraction, BET measurement, TPD-CO2 and ICP-AES analysis, respectively. Transesterification activity of solid base catalysts showed that > 90% of palm biodiesel and > 80% of Jatropha biodiesel yield under 3 wt.% of catalyst, 3 h reaction time, methanol to oil ratio of 15:1 under 65°C. This indicated that other than physicochemical characteristic of catalysts; different types of natural oil greatly influence the catalytic reaction due to the presence of free fatty acids (FFAs). Conclusions Among the solid base catalysts, calcium based mixed metal oxides catalysts with binary metal system (CaMgO and CaZnO) showed capability to maintain the transesterification activity for 3 continuous runs at ~ 80% yield. These catalysts render high durability characteristic in transesterification with low active metal leaching for several cycles. PMID:24812574

(Trans)esterification of mannose catalyzed by lipase B from Candida antarctica in an improved reaction medium using co-solvents and molecular sieve.

PubMed

Nott, Katherine; Brognaux, Alison; Richard, Gaëtan; Laurent, Pascal; Favrelle, Audrey; Jérôme, Christine; Blecker, Christophe; Wathelet, Jean-Paul; Paquot, Michel; Deleu, Magali

2012-01-01

Four co-solvents (dimethylformamide [DMF], formamide, dimethyl sulfoxide [DMSO], and pyridine) were tested with tert-butanol (tBut) to optimize the initial rate (v₀) and yield of mannosyl myristate synthesis by esterification catalyzed by immobilized lipase B from Candida antarctica. Ten percent by volume of DMSO resulted in the best improvement of v₀ and 48-hr yield (respectively 115% and 13% relative gain compared to pure tBut). Use of molecular sieve (5% w/v) enhances the 48-hr yield (55% in tBut/DMSO [9:1, v/v]). Transesterification in tBut/DMSO (9:1, v/v) with vinyl myristate leads to further improvement of v₀ and 48-hr yield: a relative gain of 85% and 65%, respectively, without sieve and 25% and 10%, respectively, with sieve, compared to esterification. No difference in v₀ and 48-hr yield is observed when transesterification is carried out with or without sieve.

Electrophilic assistance to the cleavage of an RNA model phopshodiester via specific and general base-catalyzed mechanisms.

PubMed

Corona-Martínez, David Octavio; Gomez-Tagle, Paola; Yatsimirsky, Anatoly K

2012-10-19

Kinetics of transesterification of the RNA model substrate 2-hydroxypropyl 4-nitrophenyl phosphate promoted by Mg(2+) and Ca(2+), the most common biological metals acting as cofactors for nuclease enzymes and ribozymes, as well as by Co(NH(3))(6)(3+), Co(en)(3)(3+), Li(+), and Na(+) cations, often employed as mechanistic probes, was studied in 80% v/v (50 mol %) aqueous DMSO, a medium that allows one to discriminate easily specific base (OH(-)-catalyzed) and general base (buffer-catalyzed) reaction paths. All cations assist the specific base reaction, but only Mg(2+) and Na(+) assist the general base reaction. For Mg(2+)-assisted reactions, the solvent deuterium isotope effects are 1.23 and 0.25 for general base and specific base mechanisms, respectively. Rate constants for Mg(2+)-assisted general base reactions measured with different bases fit the Brønsted correlation with a slope of 0.38, significantly lower than the slope for the unassisted general base reaction (0.77). Transition state binding constants for catalysts in the specific base reaction (K(‡)(OH)) both in aqueous DMSO and pure water correlate with their binding constants to 4-nitrophenyl phosphate dianion (K(NPP)) used as a minimalist transition state model. It was found that K(‡)(OH) ≈ K(NPP) for "protic" catalysts (Co(NH(3))(6)(3+), Co(en)(3)(3+), guanidinium), but K(‡)(OH) ≫ K(NPP) for Mg(2+) and Ca(2+) acting as Lewis acids. It appears from results of this study that Mg(2+) is unique in its ability to assist efficiently the general base-catalyzed transesterification often occurring in active sites of nuclease enzymes and ribozymes.

Green Synthesis of a Fluorescent Natural Product

ERIC Educational Resources Information Center

Young, Douglas M.; Welker, Jacob J. C.; Doxsee, Kenneth M.

2011-01-01

Synthesis of 4-methylumbelliferone via the acid-catalyzed Pechmann condensation introduces students to several types of organic reactions: transesterification, electrophilic aromatic substitution, and alcohol dehydration. Performed with a recyclable, solid catalyst and under solvent-free conditions, the experiment illustrates many of the…

Lipids for Health and Beauty: Enzymatic Modification of Vegetable Oil

USDA-ARS?s Scientific Manuscript database

Ferulic acid has been extensively investigated for its potential as a cosmetic and pharmaceutical agent. We have prepared lipophilic derivatives of ferulic acid by a simple, enzyme-catalyzed transesterification reaction of ethyl ferulate with vegetable oils. Immobilized Candida antarctica lipase B...

Lipase-catalyzed biodiesel production and quality with Jatropha curcas oil: exploring its potential for Central America.

PubMed

Bueso, Francisco; Moreno, Luis; Cedeño, Mathew; Manzanarez, Karla

2015-01-01

Extensive native Jatropha curcas L. (Jatropha) crop areas have been planted in Central America marginal lands since 2008 as a non-edible prospective feedstock alternative to high-value, edible palm oil. Jatropha biodiesel is currently exclusively produced in the region at commercial scale utilizing alkaline catalysts. Recently, a free, soluble Thermomyces lanuginosus (TL) 1,3 specific lipase has shown promise as biocatalyst, reportedly yielding up to 96 % ASTM D6751 compliant biodiesel after 24 h transesterification of soybean, canola oils and other feedstocks. Biodiesel conversion rate and quality of enzymatically catalyzed transesterification of Jatropha oil was evaluated. Two lipases: free, soluble TL and immobilized Candida antarctica (CA) catalyzed methanolic transesterification of crude Jatropha and refined palm oil. Jatropha yields were similar to palm biodiesel with NaOH as catalyst. After 24 h transesterification, Jatropha (81 %) and palm oil (86 %) biodiesel yields with TL as catalyst were significantly higher than CA (<70 %) but inferior to NaOH (>90 %). Enzymatic catalysts (TL and CA) produced Jatropha biodiesel with optimum flow properties but did not complied with ASTM D6751 stability parameters (free fatty acid content and oil stability index). Biodiesel production with filtered, degummed, low FFA Jatropha oil using a free liquid lipase (TL) as catalyst showed higher yielding potential than immobilized CA lipase as substitute of RBD palm oil with alkaline catalyst. However, Jatropha enzymatic biodiesel yield and stability were inferior to alkaline catalyzed biodiesel and not in compliance with international quality standards. Lower quality due to incomplete alcoholysis and esterification, potential added costs due to need of more than 24 h to achieve comparable biodiesel yields and extra post-transesterification refining reactions are among the remaining drawbacks for the environmentally friendlier enzymatic catalysis of crude Jatropha oil to become an economically viable alternative to chemical catalysis.

Key role of temperature monitoring in interpretation of microwave effect on transesterification and esterification reactions for biodiesel production.

PubMed

Mazubert, Alex; Taylor, Cameron; Aubin, Joelle; Poux, Martine

2014-06-01

Microwave effects have been quantified, comparing activation energies and pre-exponential factors to those obtained in a conventionally-heated reactor for biodiesel production from waste cooking oils via transesterification and esterification reactions. Several publications report an enhancement of biodiesel production using microwaves, however recent reviews highlight poor temperature measurements in microwave reactors give misleading reaction performances. Operating conditions have therefore been carefully chosen to investigate non-thermal microwave effects alone. Temperature is monitored by an optical fiber sensor, which is more accurate than infrared sensors. For the transesterification reaction, the activation energy is 37.1kJ/mol (20.1-54.2kJ/mol) in the microwave-heated reactor compared with 31.6kJ/mol (14.6-48.7kJ/mol) in the conventionally-heated reactor. For the esterification reaction, the activation energy is 45.4kJ/mol (31.8-58.9kJ/mol) for the microwave-heated reactor compared with 56.1kJ/mol (55.7-56.4kJ/mol) for conventionally-heated reactor. The results confirm the absence of non-thermal microwave effects for homogenous-catalyzed reactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Graphene oxide for acid catalyzed-reactions: Effect of drying process

NASA Astrophysics Data System (ADS)

Gong, H. P.; Hua, W. M.; Yue, Y. H.; Gao, Z.

2017-03-01

Graphene oxides (GOs) were prepared by Hummers method through various drying processes, and characterized by XRD, SEM, FTIR, XPS and N2 adsorption. Their acidities were measured using potentiometric titration and acid-base titration. The catalytic properties were investigated in the alkylation of anisole with benzyl alcohol and transesterification of triacetin with methanol. GOs are active catalysts for both reaction, whose activity is greatly affected by their drying processes. Vacuum drying GO exhibits the best performance in transesterification while freezing drying GO is most active for alkylation. The excellent catalytic behavior comes from abundant surface acid sites as well as proper surface functional groups, which can be obtained by selecting appropriate drying process.

Aquivion Perfluorosulfonic Superacid as an Efficient Pickering Interfacial Catalyst for the Hydrolysis of Triglycerides.

PubMed

Shi, Hui; Fan, Zhaoyu; Hong, Bing; Pera-Titus, Marc

2017-09-11

Rational design of the surface properties of heterogeneous catalysts can boost the interfacial activity in biphasic reactions through the generation of Pickering emulsions. This concept, termed Pickering interfacial catalysis (PIC), has shown promising credentials in acid-catalyzed transesterification, ester hydrolysis, acetalization, etherification, and alkylation reactions. PIC has now been applied to the efficient, solvent-free hydrolysis of the triglyceride glyceryl trilaurate to lauric acid, catalyzed by Aquivion perfluorosulfonic superacid at mild conditions (100 °C and ambient pressure). © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

One-step production of biodiesel from rice bran oil catalyzed by chlorosulfonic acid modified zirconia via simultaneous esterification and transesterification.

PubMed

Zhang, Yue; Wong, Wing-Tak; Yung, Ka-Fu

2013-11-01

Due to the high content (25-50%) of free fatty acid (FFA), crude rice bran oil usually requires a two steps conversion or one step conversion with very harsh condition for simultaneous esterification and transesterification. In this study, chlorosulfonic acid modified zirconia (HClSO3-ZrO2) with strong acidity and durability is prepared and it shows excellent catalytic activity toward simultaneous esterification and transesterification. Under a relative low reaction temperature of 120 °C, HClSO3-ZrO2 catalyzes a complete conversion of simulated crude rice bran oil (refined oil with 40 wt% FFA) into biodiesel and the conversion yield keep at above 92% for at least three cycles. Further investigation on the tolerance towards FFA and water reveals that it maintains high activity even with the presence of 40 wt% FFA and 3 wt% water. It shows that HClSO3-ZrO2 is a robust and durable catalyst which shows high potential to be commercial catalyst for biodiesel production from low grade feedstock. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodiesel synthesis by TiO2-ZnO mixed oxide nanocatalyst catalyzed palm oil transesterification process.

PubMed

Madhuvilakku, Rajesh; Piraman, Shakkthivel

2013-12-01

Biodiesel is a promising alternating environmentally benign fuel to mineral diesel. For the development of easier transesterification process, stable and active heterogeneous mixed metal oxide of TiO2-ZnO and ZnO nanocatalysts were synthesized and exploited for the palm oil transesterification process. The synthesized catalysts were characterized by XRD, FT-IR, and FE-SEM studies for their structural and morphological characteristics. It was found that TiO2-ZnO nanocatalyst exhibits good catalytic activity and the catalytic performance was greatly depends on (i) catalyst concentration (ii) methanol to oil molar ratio (iii) reaction temperature and (iv) reaction time. A highest 98% of conversion was obtained at the optimum reaction parameters with 200 mg of catalyst loading and the biodiesel was analyzed by TLC and (1)H NMR techniques. The TiO2-ZnO nanocatalyst shows good catalytic performance over the ZnO catalyst, which could be a potential candidate for the large-scale biodiesel production from palm oil at the reduced temperature and time. Copyright © 2013. Published by Elsevier Ltd.

Biodiesel production with special emphasis on lipase-catalyzed transesterification.

PubMed

Bisen, Prakash S; Sanodiya, Bhagwan S; Thakur, Gulab S; Baghel, Rakesh K; Prasad, G B K S

2010-08-01

The production of biodiesel by transesterification employing acid or base catalyst has been industrially accepted for its high conversion and reaction rates. Downstream processing costs and environmental problems associated with biodiesel production and byproducts recovery have led to the search for alternative production methods. Recently, enzymatic transesterification involving lipases has attracted attention for biodiesel production as it produces high purity product and enables easy separation from the byproduct, glycerol. The use of immobilized lipases and immobilized whole cells may lower the overall cost, while presenting less downstream processing problems, to biodiesel production. The present review gives an overview on biodiesel production technology and analyzes the factors/methods of enzymatic approach reported in the literature and also suggests suitable method on the basis of evidence for industrial production of biodiesel.

New ether-functionalized ionic liquids for lipase-catalyzed synthesis of biodiesel.

PubMed

Zhao, Hua; Song, Zhiyan; Olubajo, Olarongbe; Cowins, Janet V

2010-09-01

Ionic liquids (ILs) are being explored as solvents for the enzymatic methanolysis of triglycerides. However, most available ILs (especially hydrophobic ones) have poor capability in dissolving lipids, while hydrophilic ILs tend to cause enzyme inactivation. Recently, we synthesized a new type of ether-functionalized ionic liquids (ILs) carrying anions of acetate or formate; they are capable of dissolving a variety of substrates and are also lipase-compatible (Green Chem., 2008, 10, 696-705). In the present study, we carried out the lipase-catalyzed transesterifications of Miglyol oil 812 and soybean oil in these novel ILs. These ILs are capable of dissolving oils at the reaction temperature (50 degrees C); meanwhile, lipases maintained high catalytic activities in these media even in high concentrations of methanol (up to 50% v/v). High conversions of Miglyol oil were observed in mixtures of IL and methanol (70/30, v/v) when the reaction was catalyzed by a variety of lipases and different enzyme preparations (free and immobilized), especially with the use of two alkylammonium ILs 2 and 3. The preliminary study on the transesterification of soybean oil in IL/methanol mixtures further confirms the potential of using oil-dissolving and lipase-stabilizing ILs in the efficient production of biodiesels.

The mechanism and thermodynamics of transesterification of acetate-ester enolates in the gas phase

NASA Astrophysics Data System (ADS)

Haas, George W.; Giblin, Daryl E.; Gross, Michael L.

1998-01-01

In solution, base-catalyzed hydrolysis and transesterification of esters are initiated by hydroxide- or alkoxide-ion attack at the carbonyl carbon. At low pressures in the gas phase, however, transesterification proceeds by an attack of the enolate anion of an acetate ester on an alcohol. Fourier transform mass spectrometry (FTMS) indicates that the reaction is the second-order process: -CH2-CO2-R + R'-OH --> - CH2-CO2-R' + R-OH and there is little to no detectable production of either alkoxide anion. Labeling studies show that the product and reactant enolate anion esters undergo exchange of hydrogens located [alpha] to the carbonyl carbon with the deuterium of R'-OD. The extent of the H/D exchange increases with reaction time, pointing to a short-lived intermediate. The alcoholysis reaction rate constants increase with increasing acidity of the primary, straight-chained alkyl alcohols, whereas steric effects associated with branched alcohols cause the rate constants to decrease. Equilibrium constants, which were determined directly from measurements at equilibrium and which were calculated from the forward and reverse rate constants, are near unity and show internal consistency. In the absence of steric effects, the larger enolate is always the favored product at equilibrium. The intermediate for the transesterification reaction, which can be generated at a few tenths of a torr in a tandem mass spectrometer, is tetrahedral, but other adducts that are collisionally stabilized under these conditions are principally loosely bound complexes.

Calcium Oxide Derived from Waste Shells of Mussel, Cockle, and Scallop as the Heterogeneous Catalyst for Biodiesel Production

PubMed Central

Chaiyut, Nattawut; Worawanitchaphong, Phatsakon

2013-01-01

The waste shell was utilized as a bioresource of calcium oxide (CaO) in catalyzing a transesterification to produce biodiesel (methyl ester). The economic and environmen-friendly catalysts were prepared by a calcination method at 700–1,000°C for 4 h. The heterogeneous catalysts were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), and the Brunauer-Emmett-Teller (BET) method. The effects of reaction variables such as reaction time, reaction temperature, methanol/oil molar ratio, and catalyst loading on the yield of biodiesel were investigated. Reusability of waste shell catalyst was also examined. The results indicated that the CaO catalysts derived from waste shell showed good reusability and had high potential to be used as biodiesel production catalysts in transesterification of palm oil with methanol. PMID:24453854

Catalytic activity of calcium-based mixed metal oxides nanocatalysts in transesterification reaction of palm oil

NASA Astrophysics Data System (ADS)

Hassan, Noraakinah; Ismail, Kamariah Noor; Hamid, Ku Halim Ku; Hadi, Abdul

2017-12-01

Nowadays, biodiesel has become the forefront development as an alternative diesel fuel derived from biological sources such as oils of plant and fats. Presently, the conventional transesterification of vegetable oil to biodiesel gives rise to some technological problem. In this sense, heterogeneous nanocatalysts of calcium-based mixed metal oxides were synthesized through sol-gel method. It was found that significant increase of biodiesel yield, 91.75 % was obtained catalyzed by CaO-NbO2 from palm oil compared to pure CaO of 53.99 % under transesterification conditions (methanol/oil ratio 10:1, reaction time 3 h, catalyst concentration 4 wt%, reaction temperature 60 °C, and mixing speed of 600 rpm). The phase structure and crystallinity as well as the texture properties of the prepared catalysts were characterized by X-ray Diffraction (XRD) and the textural properties were characterized by N2 adsorption-desorption analysis. Sol-gel method has been known as versatile method in controlling the structural and chemical properties of the catalyst. Calcium-based mixed oxide synthesized from sol-gel method was found to exist as smaller crystallite size with high surface area.

Biodiesel synthesis using calcined layered double hydroxide catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumaker, J. Link; Crofcheck, Czarena; TAckett, S. Adam

2008-01-01

The catalytic properties of calcined Li-Al, Mg-Al and Mg-Fe layered double hydroxides (LDHs) were examined in two transesterification reactions, namely, the reaction of glyceryl tributyrate with methanol, and the reaction of soybean oil with methanol. While the Li-Al catalysts showed high activity in these reactions at the reflux temperature of methanol, the Mg-Fe and Mg-Al catalysts exhibited much lower methyl ester yields. CO2 TPD measurements revealed the presence of sites of weak, medium and strong basicity on both Mg-Al and Li-Al catalysts, the latter showing higher concentrations of medium and strong base sites; by implication, these are the main sitesmore » active in transesterification catalyzed by calcined Li-Al LDHs. Maximum activity was observed for the Li-Al catalysts when a calcination temperature of 450-500 aC was applied, corresponding to decomposition of the layered double hydroxide to the mixed oxide without formation of crystalline lithium aluminate phases.« less

Production and Characterization of Ethyl Ester from Crude Jatropha curcas Oil having High Free Fatty Acid Content

NASA Astrophysics Data System (ADS)

Kumar, Rajneesh; Dixit, Anoop; Singh, Shashi Kumar; Singh, Gursahib; Sachdeva, Monica

2015-09-01

The two step process was carried out to produce biodiesel from crude Jatropha curcas oil. The pretreatment process was carried out to reduce the free fatty acid content by (≤2 %) acid catalyzed esterification. The optimum reaction conditions for esterification were reported to be 5 % H2SO4, 20 % ethanol and 1 h reaction time at temperature of 65 °C. The pretreatment process reduced the free fatty acid of oil from 7 to 1.85 %. In second process, alkali catalysed transesterification of pretreated oil was carried and the effects of the varying concentrations of KOH and ethanol: oil ratios on percent ester recovery were investigated. The optimum reaction conditions for transesterification were reported to be 3 % KOH (w/v of oil) and 30 % (v/v) ethanol: oil ratio and reaction time 2 h at 65 °C. The maximum percent recovery of ethyl ester was reported to be 60.33 %.

Influence of the reaction conditions on the enzyme catalyzed transesterification of castor oil: A possible step in biodiesel production.

PubMed

Andrade, Thalles A; Errico, Massimiliano; Christensen, Knud V

2017-11-01

The identification of the influence of the reaction parameters is of paramount importance when defining a process design. In this work, non-edible castor oil was reacted with methanol to produce a possible component for biodiesel blends, using liquid enzymes as the catalyst. Temperature, alcohol-to-oil molar ratio, enzyme and added water contents were the reaction parameters evaluated in the transesterification reactions. The optimal conditions, giving the optimal final FAME yield and FFA content in the methyl ester-phase was identified. At 35°C, 6.0 methanol-to-oil molar ratio, 5wt% of enzyme and 5wt% of water contents, 94% of FAME yield and 6.1% of FFA in the final composition were obtained. The investigation was completed with the analysis of the component profiles, showing that at least 8h are necessary to reach a satisfactory FAME yield together with a minor FFA content. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dimethyl carbonate-mediated lipid extraction and lipase-catalyzed in situ transesterification for simultaneous preparation of fatty acid methyl esters and glycerol carbonate from Chlorella sp. KR-1 biomass.

PubMed

Jo, Yoon Ju; Lee, Ok Kyung; Lee, Eun Yeol

2014-04-01

Fatty acid methyl esters (FAMEs) and glycerol carbonate were simultaneously prepared from Chlorella sp. KR-1 containing 40.9% (w/w) lipid using a reactive extraction method with dimethyl carbonate (DMC). DMC was used as lipid extraction agent, acyl acceptor for transesterification of the extracted triglycerides, substrate for glycerol carbonate synthesis from glycerol, and reaction medium for the solvent-free reaction system. For 1g of biomass, 367.31 mg of FAMEs and 16.73 mg of glycerol carbonate were obtained under the optimized conditions: DMC to biomass ratio of 10:1 (v/w), water content of 0.5% (v/v), and Novozyme 435 to biomass ratio of 20% (w/w) at 70°C for 24h. The amount of residual glycerol was only in the range of 1-2.5mg. Compared to conventional method, the cost of FAME production with the proposed technique could be reduced by combining lipid extraction with transesterification and omitting the extraction solvent recovery process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enzymatic production of biodiesel from microalgal oil using ethyl acetate as an acyl acceptor.

PubMed

Alavijeh, Razieh Shafiee; Tabandeh, Fatemeh; Tavakoli, Omid; Karkhane, Aliasghar; Shariati, Parvin

2015-01-01

Microalgae have become an important source of biomass for biodiesel production. In enzymatic transesterification reaction, the enzyme activity is decreased in presence of alcohols. The use of different acyl acceptors such as methyl/ethyl acetate is suggested as an alternative and effective way to overcome this problem. In this study, ethyl acetate was used for the first time in the enzymatic production of biodiesel by using microalga, Chlorella vulgaris, as a triglyceride source. Enzymatic conversion of such fatty acids to biodiesel was catalyzed by Novozym 435 as an efficient immobilized lipase which is extensively used in biodiesel production. The best conversion yield of 66.71% was obtained at the ethyl acetate to oil molar ratio of 13:1 and Novozym 435 concentration of 40%, based on the amount of oil, and a time period of 72 h at 40℃. The results showed that ethyl acetate have no adverse effect on lipase activity and the biodiesel amount was not decreased even after seven transesterification cycles, so ethyl acetate has a great potential to be substituted for short-chain alcohols in transesterification reaction.

RSM based optimization of chemical and enzymatic transesterification of palm oil: biodiesel production and assessment of exhaust emission levels.

PubMed

Mumtaz, Muhammad Waseem; Mukhtar, Hamid; Anwar, Farooq; Saari, Nazamid

2014-01-01

Current study presents RSM based optimized production of biodiesel from palm oil using chemical and enzymatic transesterification. The emission behavior of biodiesel and its blends, namely, POB-5, POB-20, POB-40, POB-50, POB-80, and POB-100 was examined using diesel engine (equipped with tube well). Optimized palm oil fatty acid methyl esters (POFAMEs) yields were depicted to be 47.6 ± 1.5, 92.7 ± 2.5, and 95.4 ± 2.0% for chemical transesterification catalyzed by NaOH, KOH, and NaOCH3, respectively, whereas for enzymatic transesterification reactions catalyzed by NOVOZYME-435 and A. n. lipase optimized biodiesel yields were 94.2 ± 3.1 and 62.8 ± 2.4%, respectively. Distinct decrease in particulate matter (PM) and carbon monoxide (CO) levels was experienced in exhaust emissions from engine operating on biodiesel blends POB-5, POB-20, POB-40, POB-50, POB-80, and POB-100 comparative to conventional petroleum diesel. Percentage change in CO and PM emissions for different biodiesel blends ranged from -2.1 to -68.7% and -6.2 to -58.4%, respectively, relative to conventional diesel, whereas an irregular trend was observed for NOx emissions. Only POB-5 and POB-20 showed notable reductions, whereas all other blends (POB-40 to POB-100) showed slight increase in NOx emission levels from 2.6 to 5.5% comparative to petroleum diesel.

RSM Based Optimization of Chemical and Enzymatic Transesterification of Palm Oil: Biodiesel Production and Assessment of Exhaust Emission Levels

PubMed Central

Mumtaz, Muhammad Waseem; Anwar, Farooq; Saari, Nazamid

2014-01-01

Current study presents RSM based optimized production of biodiesel from palm oil using chemical and enzymatic transesterification. The emission behavior of biodiesel and its blends, namely, POB-5, POB-20, POB-40, POB-50, POB-80, and POB-100 was examined using diesel engine (equipped with tube well). Optimized palm oil fatty acid methyl esters (POFAMEs) yields were depicted to be 47.6 ± 1.5, 92.7 ± 2.5, and 95.4 ± 2.0% for chemical transesterification catalyzed by NaOH, KOH, and NaOCH3, respectively, whereas for enzymatic transesterification reactions catalyzed by NOVOZYME-435 and A. n. lipase optimized biodiesel yields were 94.2 ± 3.1 and 62.8 ± 2.4%, respectively. Distinct decrease in particulate matter (PM) and carbon monoxide (CO) levels was experienced in exhaust emissions from engine operating on biodiesel blends POB-5, POB-20, POB-40, POB-50, POB-80, and POB-100 comparative to conventional petroleum diesel. Percentage change in CO and PM emissions for different biodiesel blends ranged from −2.1 to −68.7% and −6.2 to −58.4%, respectively, relative to conventional diesel, whereas an irregular trend was observed for NOx emissions. Only POB-5 and POB-20 showed notable reductions, whereas all other blends (POB-40 to POB-100) showed slight increase in NOx emission levels from 2.6 to 5.5% comparative to petroleum diesel. PMID:25162053

Erratum to "The mechanism and thermodynamics of transesterification of acetate-ester enolates in the gas phase" : [Int. J. Mass Spectrom. Ion Process. 172 (1998) 25

NASA Astrophysics Data System (ADS)

Haas, George W.; Giblin, Daryl E.; Gross, Michael L.

1998-02-01

In solution, base-catalyzed hydrolysis and transesterification of esters are initiated by hydroxide- or alkoxide-ion attack at the carbonyl carbon. At low pressures in the gas phase, however, transesterification proceeds by an attack of the enolate anion of an acetate ester on an alcohol. Fourier transform mass spectrometry (FTMS) indicates that the reaction is the second-order process: -CH2-CO2-R+R'-OH-->-CH2-CO2-R'+R-OH and there is little to no detectable production of either alkoxide anion. Labeling studies show that the product and reactant enolate anion esters undergo exchange of hydrogens located [alpha] to the carbonyl carbon with the deuterium of R'--OD. The extent of the H/D exchange increases with reaction time, pointing to a short-lived intermediate. The alcoholysis reaction rate constants increase with increasing acidity of the primary, straight-chained alkyl alcohols, whereas steric effects associated with branched alcohols cause the rate constants to decrease. Equilibrium constants, which were determined directly from measurements at equilibrium and which were calculated from the forward and reverse rate constants, are near unity and show internal consistency. In the absence of steric effects, the larger enolate is always the favored product at equilibrium. The intermediate for the transesterification reaction, which can be generated at a few tenths of a torr in a tandem mass spectrometer, is tetrahedral, but other adducts that are collisionally stabilized under these conditions are principally loosely bound complexes.

Cavitation assisted synthesis of fatty acid methyl esters from sustainable feedstock in presence of heterogeneous catalyst using two step process.

PubMed

Dubey, Sumit M; Gole, Vitthal L; Gogate, Parag R

2015-03-01

The present work reports the intensification aspects for the synthesis of fatty acid methyl esters (FAME) from a non-edible high acid value Nagchampa oil (31 mg of KOH/g of oil) using two stage acid esterification (catalyzed by H₂SO₄) followed by transesterification in the presence of heterogeneous catalyst (CaO). Intensification aspects of both stages have been investigated using sonochemical reactors and the obtained degree of intensification has been established by comparison with the conventional approach based on mechanical agitation. It has been observed that reaction temperature for esterification reduced from 65 to 40 °C for the ultrasonic approach whereas there was a significant reduction in the optimum reaction time for transesterification from 4h for the conventional approach to 2.5h for the ultrasound assisted approach. Also the reaction temperature reduced marginally from 65 to 60 °C and yield increased from 76% to 79% for the ultrasound assisted approach. Energy requirement and activation energy for both esterification and transesterification was lower for the ultrasound based approach as compared to the conventional approach. The present work has clearly established the intensification obtained due to the use of ultrasound and also illustrated the two step approach for the synthesis of FAME from high acid value feedstock based on the use of heterogeneous catalyst for the transesterification step. Copyright © 2014 Elsevier B.V. All rights reserved.

Biodiesel production from Nannochloropsis gaditana lipids through transesterification catalyzed by Rhizopus oryzae lipase.

PubMed

Navarro López, Elvira; Robles Medina, Alfonso; González Moreno, Pedro Antonio; Esteban Cerdán, Luis; Martín Valverde, Lorena; Molina Grima, Emilio

2016-03-01

Biodiesel (fatty acid methyl esters, FAMEs) was produced from saponifiable lipids (SLs) extracted from wet Nannochloropsis gaditana biomass using methanolysis catalyzed by Rhizopus oryzae intracellular lipase. SLs were firstly extracted with ethanol to obtain 31 wt% pure SLs. But this low SL purity also gave a low biodiesel conversion (58%). This conversion increased up to 80% using SLs purified by crystallization in acetone (95 wt% purity). Polar lipids play an important role in decreasing the reaction velocity - using SLs extracted with hexane, which have lower polar lipid content (37.4% versus 49.0% using ethanol), we obtained higher reaction velocities and less FAME conversion decrease when the same lipase batch was reused. 83% of SLs were transformed to biodiesel using a 70 wt% lipase/SL ratio, 11:1 methanol/SL molar ratio, 10 mL t-butanol/g SLs after 72 h. The FAME conversion decreased to 71% after catalyzing three reactions with the same lipase batch. Copyright © 2015 Elsevier Ltd. All rights reserved.

Methyl Ester Production via Heterogeneous Acid-Catalyzed Simultaneous Transesterification and Esterification Reactions

NASA Astrophysics Data System (ADS)

Indrayanah, S.; Erwin; Marsih, I. N.; Suprapto; Murwani, I. K.

2017-05-01

The heterogeneous acid catalysts (MgF2 and ZnF2) have been used to catalyze the simultaneous transesterification and esterification reactions of crude palm oil (CPO) with methanol. Catalysts were synthesized by sol-gel method (combination of fluorolysis and hydrolysis). The physicochemical, structural, textural, thermal stability of the prepared catalysts was investigated by N2 adsorption-desorption, XRD, FT-IR, SEM and TG/DTG. Both MgF2 and ZnF2 have rutile structures with a different phase. The surface area of ZnF2 is smaller than that of MgF2, but the pore size and volume of ZnF2 are larger than those of MgF2. However, these materials are thermally stable. The performance of the catalysts is determined from the yield of catalysts toward the formation of methyl ester determined based on the product of methyl ester obtained from the reaction. The catalytic activity of ZnF2 is higher than MgF2 amounted to 85.21% and 26.82% with the optimum condition. The high activity of ZnF2 could be attributed to its pore diameter and pore volume but was not correlated with its surface area. The yield of methyl ester decreased along with the increase in molar ratio of methanol/CPO from 85.21 to 80.99 for ZnF2, respectively.

Ultrasound assisted two-stage biodiesel synthesis from non-edible Schleichera triguga oil using heterogeneous catalyst: Kinetics and thermodynamic analysis.

PubMed

Sarve, Antaram N; Varma, Mahesh N; Sonawane, Shriram S

2016-03-01

Present work deals with the ultrasound-assisted biodiesel production from low cost, substantial acid value kusum (Schleichera triguga) oil using a two-step method of esterification in presence of acid (H2SO4) catalyst followed by transesterification using a basic heterogeneous barium hydroxide (Ba(OH)2) catalyst. The initial acid value of kusum oil was reduced from 21.65 to 0.84 mg of KOH/g of oil, by acid catalyzed esterification with 4:1 methanol to oil molar ratio, catalyst concentration 1% (v/v), ultrasonic irradiation time 20 min at 40 °C. Then, Ba(OH)2 concentration of 3% (w/w), methanol to oil molar ratio of 9:1, ultrasonic irradiation time of 80 min, and temperature of 50 °C was found to be the optimum conditions for transesterification step and triglyceride conversion of 96.8% (wt) was achieved. This paper also examined the kinetics as well as the evaluation of thermodynamic parameters for both esterification and transesterification reactions. The lower value of activation energy and higher values of kinetic constants indicated a fast rate of reaction, which could be attributed to the physical effect of emulsification, in which the microturbulence generated due to radial motion of bubbles, creates an intimate mixing of the immiscible reactants causing the increase in the interfacial area, giving faster reaction kinetics. The positive values of Gibbs-free energy (ΔG), enthalpy (ΔH) and negative value of entropy (ΔS) revealed that both the esterification and transesterification were non-spontaneous, endothermic and endergonic reactions. Therefore, the present work has not only established the escalation obtained due to ultrasonication but also exemplified the two-step approach for synthesis of biodiesel from non-edible kusum oil based on the use of heterogeneous catalyst for the transesterification step. Copyright © 2015 Elsevier B.V. All rights reserved.

Economical and green biodiesel production process using river snail shells-derived heterogeneous catalyst and co-solvent method.

PubMed

Roschat, Wuttichai; Siritanon, Theeranun; Kaewpuang, Teadkait; Yoosuk, Boonyawan; Promarak, Vinich

2016-06-01

River snail shells-derived CaO was used as a heterogeneous catalyst to synthesize biodiesel via transesterification of palm oil with methanol. The shell materials were calcined in air at 600-1000°C for 3h. Physicochemical properties of the resulting catalysts were characterized by TGA-DTG, XRD, SEM, BET, XRF, FT-IR and TPD. CaO catalyzed transesterification mechanism of palm oil into biodiesel was verified. The effects of adding a co-solvent on kinetic of the reaction and %FAME yield were investigated. %FAME yield of 98.5%±1.5 was achieved under the optimal conditions of catalyst/oil ratio of 5wt.%; methanol/oil molar ratio of 12:1; reaction temperature of 65°C; 10%v/v of THF in methanol and reaction time of 90min. The results ascertained that river snail shells is a novel raw material for preparation of CaO catalyst and the co-solvent method successfully decreases the reaction time and biodiesel production cost. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodiesel production from crude Jatropha oil catalyzed by non-commercial immobilized heterologous Rhizopus oryzae and Carica papaya lipases.

PubMed

Rodrigues, J; Canet, A; Rivera, I; Osório, N M; Sandoval, G; Valero, F; Ferreira-Dias, S

2016-08-01

The aim of this study was to evaluate the feasibility of biodiesel production by transesterification of Jatropha oil with methanol, catalyzed by non-commercial sn-1,3-regioselective lipases. Using these lipases, fatty acid methyl esters (FAME) and monoacylglycerols are produced, avoiding the formation of glycerol as byproduct. Heterologous Rhizopus oryzae lipase (rROL) immobilized on different synthetic resins and Carica papaya lipase (rCPL) immobilized on Lewatit VP OC 1600 were tested. Reactions were performed at 30°C, with seven stepwise methanol additions. For all biocatalysts, 51-65% FAME (theoretical maximum=67%, w/w) was obtained after 4h transesterification. Stability tests were performed in 8 or 10 successive 4h-batches, either with or without rehydration of the biocatalyst between each two consecutive batches. Activity loss was much faster when biocatalysts were rehydrated. For rROL, half-life times varied from 16 to 579h. rROL on Lewatit VPOC 1600 was more stable than for rCPL on the same support. Copyright © 2016 Elsevier Ltd. All rights reserved.

Ionic Liquid Droplet Microreactor for Catalysis Reactions Not at Equilibrium.

PubMed

Zhang, Ming; Ettelaie, Rammile; Yan, Tao; Zhang, Suojiang; Cheng, Fangqin; Binks, Bernard P; Yang, Hengquan

2017-12-06

We develop a novel strategy to more effectively and controllably process continuous enzymatic or homogeneous catalysis reactions based on nonaqueous Pickering emulsions. A key element of this strategy is "bottom-up" construction of a macroscale continuous flow reaction system through packing catalyst-containing micron-sized ionic liquid (IL) droplet in oil in a column reactor. Due to the continuous influx of reactants into the droplet microreactors and the continuous release of products from the droplet microreactors, catalysis reactions in such a system can take place without limitations arising from establishment of the reaction equilibrium and catalyst separation, inherent in conventional batch reactions. As proof of the concept, enzymatic enantioselective trans-esterification and CuI-catalyzed cycloaddition reactions using this IL droplet-based flow system both exhibit 8 to 25-fold enhancement in catalysis efficiency compared to their batch counterparts, and a durability of at least 4000 h for the enantioselective trans-esterification of 1-phenylethyl alcohol, otherwise unattainable in their batch counterparts. We further establish a theoretical model for such a catalysis system working under nonequilibrium conditions, which not only supports the experimental results but also helps to predict reaction progress at a microscale level. Being operationally simple, efficient, and adaptive, this strategy provides an unprecedented platform for practical applications of enzymes and homogeneous catalysts even at a controllable level.

Preparation of Biodiesel from Microalgae and Palm Oil by Direct Transesterification in a Batch Microwave Reactor

NASA Astrophysics Data System (ADS)

Marwan; Suhendrayatna; Indarti, E.

2015-06-01

The present work was aimed to study the so-called direct transesterification of microalgae lipids to biodiesel in a batch microwave reactor. As a comparison, preparation of palm oil to biodiesel by alkaline catalyzed ethanolysis was also carried out. Palm oil biodiesel was recovered close to an equilibrium conversion (94-96% yield) under microwave heating for at least 6 min, while the conventional method required more than 45 minutes reaching the same yield. A very short reaction time suggests the benefit of microwave effect over conventional heating method in making biodiesel. FTIR analysis revealed the presence of fatty acid ethyl esters with no undesired chemical groups or compounds formed due to local heat generated by microwave effect, thus the conversion only followed transesterification route. Oil containing microalgae of Chlorella sp. isolated from the local brackish water pond was used as a potential source of biodiesel. High yield of biodiesel (above 0.6 g/g of dried algae) was also attainable for the direct transesterification of microalgae in the microwave reactor. Effect of water content of the algae biomass became insignificant at 11.9%(w/w) or less, related to the algae biomass dried for longer than 6 h. Fast transesterification of the algal oil towards equilibrium conversion was obtained at reaction time of 6 min, and at longer times the biodiesel yield remains unchanged. FAME profile indicates unsaturated fatty acids as major constituents. It was shown that microwave irradiation contributes not only to enhance the transeseterification, but also to assist effective release of fatty acid containing molecules (e.g. triacylglycerol, free fatty acids and phospholipids) from algal cells.

Extraction of microalgal lipids and the influence of polar lipids on biodiesel production by lipase-catalyzed transesterification.

PubMed

Navarro López, Elvira; Robles Medina, Alfonso; González Moreno, Pedro Antonio; Esteban Cerdán, Luis; Molina Grima, Emilio

2016-09-01

In order to obtain microalgal saponifiable lipids (SLs) fractions containing different polar lipid (glycolipids and phospholipids) contents, SLs were extracted from wet Nannochloropsis gaditana microalgal biomass using seven extraction systems, and the polar lipid contents of some fractions were reduced by low temperature acetone crystallization. We observed that the polar lipid content in the extracted lipids depended on the polarity of the first solvent used in the extraction system. Lipid fractions with polar lipid contents between 75.1% and 15.3% were obtained. Some of these fractions were transformed into fatty acid methyl esters (FAMEs, biodiesel) by methanolysis, catalyzed by the lipases Novozym 435 and Rhizopus oryzae in tert-butanol medium. We observed that the reaction velocity was higher the lower the polar lipid content, and that the final FAME conversions achieved after using the same lipase batch to catalyze consecutive reactions decreased in relation to an increase in the polar lipid content. Copyright © 2016 Elsevier Ltd. All rights reserved.

Lipase-Catalyzed Kinetic Resolution of Novel Antifungal N-Substituted Benzimidazole Derivatives.

PubMed

Łukowska-Chojnacka, Edyta; Staniszewska, Monika; Bondaryk, Małgorzata; Maurin, Jan K; Bretner, Maria

2016-04-01

A series of new N-substituted benzimidazole derivatives was synthesized and their antifungal activity against Candida albicans was evaluated. The chemical step included synthesis of appropriate ketones containing benzimidazole ring, reduction of ketones to the racemic alcohols, and acetylation of alcohols to the esters. All benzimidazole derivatives were obtained with satisfactory yields and in relatively short times. All synthesized compounds exhibit significant antifungal activity against Candida albicans 900028 ATCC (% cell inhibition at 0.25 μg concentration > 98%). Additionally, racemic mixtures of alcohols were separated by lipase-catalyzed kinetic resolution. In the enzymatic step a transesterification reaction was applied and the influence of a lipase type and solvent on the enantioselectivity of the reaction was studied. The most selective enzymes were Novozyme SP 435 and lipase Amano AK from Pseudomonas fluorescens (E > 100). © 2016 Wiley Periodicals, Inc.

Kinetics study of Jatropha oil esterification with ethanol in the presence of tin (II) chloride catalyst for biodiesel production

NASA Astrophysics Data System (ADS)

Kusumaningtyas, Ratna Dewi; Ratrianti, Naomi; Purnamasari, Indah; Budiman, Arief

2017-01-01

Jatropha oil is one of the promising feedstocks for biodiesel production. Jatropha oil is non-edible oil hence utilization of this oil would not compete with the needs of food. However, crude jatropha oil usually has high free fatty acid (FFA) content. Due to this fact, direct alkaline-catalyzed transesterification of crude jatropha oil for biodiesel production cannot be performed. FFA in crude jatropha oil will react with a base catalyst, resulting in soap as by product and hindering methyl ester (biodiesel) production. Therefore, prior to a transesterification reaction, it is crucial to run a pretreatment step of jatropha oil which can lower the FFA content in the oil. In this work, the pretreatment process was conducted through the esterification reaction of FFA contained in crude jatropha oil with ethanol over tin (II) chloride catalyst to reduce the acid value of the feedstock. The feedstock was Indonesia crude jatropha oil containing 12.03% of FFA. The esterification reaction was carried out in a batch reactor with a molar ratio of FFA to ethanol was 1:60 and total reaction time was 180 minutes. Tin (II) chloride catalyst was varied at 2.5, 5, 7.5, and 10% wt, whereas the effect of the reaction temperature was studied at 35, 34, 55, and 65 °C. The best reaction conversion was 71.55%, achieved at the following condition: a reaction temperature of 65 °C, catalyst concentration of 10% wt, the reaction time of 180 min, and the molar ratio of FFA to ethanol was 1:60. Kinetics study was also conducted in this work. It was found that esterification reaction of jatropha oil FFA with ethanol catalyzed by tin(II) chloride fitted the first-order pseudo-homogeneous kinetics model. It was also revealed that the frequency factor (A) and the activation energy (Ea) were 4.3864 × 106 min-1 and 56.2513 kJ/mole, respectively.

Candida rugosa lipase LIP1-catalyzed transesterification to produce human milk fat substitute.

PubMed

Srivastava, Anita; Akoh, Casimir C; Chang, Shu-Wei; Lee, Guan-Chiun; Shaw, Jei-Fu

2006-07-12

Structured lipids (SLs) containing palmitic and oleic acids were synthesized by transesterification of tripalmitin with either oleic acid or methyl oleate as acyl donor. This SL with palmitic acid at the sn-2 position and oleic acid at sn-1,3 positions is similar in structure to human milk fat triacylglycerol. LIP1, an isoform of Candida rugosa lipase (CRL), was used as biocatalyst. The effects of reaction temperature, substrate molar ratio, and time on incorporation of oleic acid were investigated. Reaction time and temperature were set at 6, 12, and 24 h, and 35, 45, and 55 degrees C, respectively. Substrate molar ratio was varied from 1:1 to 1:4. The highest incorporation of oleic acid (37.7%) was at 45 degrees C with methyl oleate as acyl donor. Oleic acid resulted in slightly lesser (26.3%) incorporation. Generally, higher percentage incorporation of oleic acid was observed with methyl oleate (transesterification) than with oleic acid (acidolysis). In both cases percentage incorporation increased with reaction time. Incorporation decreased with increase in temperature above 45 degrees C. Initially, oleic acid incorporation increased with increase in substrate molar ratio up to 1:3. LIP1 was also compared with Lipozyme RM IM as biocatalysts. The tested reaction parameters were selected on the basis of maximum incorporation of C18:1 obtained during optimization of LIP1 reaction conditions. Reaction temperature was maintained at 45, 55, and 65 degrees C. Lipozyme RM IM gave highest oleic acid incorporation (49.4%) at 65 degrees C with methyl oleate as acyl donor. Statistically significant (P < 0.05) differences were observed for both enzymes. SL prepared using Lipozyme RM IM may be more suitable for possible use in human milk fat substitutes.

Function and application of a non-ester-hydrolyzing carboxylesterase discovered in tulip.

PubMed

Nomura, Taiji

2017-01-01

Plants have evolved secondary metabolite biosynthetic pathways of immense rich diversity. The genes encoding enzymes for secondary metabolite biosynthesis have evolved through gene duplication followed by neofunctionalization, thereby generating functional diversity. Emerging evidence demonstrates that some of those enzymes catalyze reactions entirely different from those usually catalyzed by other members of the same family; e.g. transacylation catalyzed by an enzyme similar to a hydrolytic enzyme. Tuliposide-converting enzyme (TCE), which we recently discovered from tulip, catalyzes the conversion of major defensive secondary metabolites, tuliposides, to antimicrobial tulipalins. The TCEs belong to the carboxylesterase family in the α/β-hydrolase fold superfamily, and specifically catalyze intramolecular transesterification, but not hydrolysis. This non-ester-hydrolyzing carboxylesterase is an example of an enzyme showing catalytic properties that are unpredictable from its primary structure. This review describes the biochemical and physiological aspects of tulipalin biogenesis, and the diverse functions of plant carboxylesterases in the α/β-hydrolase fold superfamily.

Comparing Ultrasound and Mechanical Steering in a Biodiesel Production Process

NASA Astrophysics Data System (ADS)

Costa-Felix, Rodrigo P. B.; Ferreira, Jerusa R. L.

The analysis of the kinetics of the transesterification reaction is crucial to compare different routes or routes with different catalysts or reaction accelerators. The use of ultrasound is considereda method for accelerating the biodiesel production. However, little effort has been done and is reported in the literature about how and under what conditions the use of ultrasound really speeds up the process, or the conditions under which its use is unnecessary or even harmful, burdening the process. Two dissimilar energy injections into a typical route were tested: ultrasound (@ 1 MHz and no heating) and mechanical steering (with heating), both applied in an 8:1 ratio of soybean oil and methanol, adding 1% of KOH as catalyzer. As results, during the first 10 minutes of reaction ultrasound showed unbearable effect on the transesterification, whilst mechanical steering and heating achieved almost 70% of conversion ratio. However, during the following 10 minutes, the mechanical steering and heating got nothing more than 80% of conversion, a considerable less efficient process than ultrasound assisted one, which achieved more than 90%. The straightforward explanation is that ultrasound continually inserts energy in a slower rate, what can result in a more stable conversion scenario. On the other hand, mechanical steering and heating provides more energy at a glance, but cannot push the final conversion rate beyond a limit, as the transesterification is a double-way chemical process. The instability mechanical steering and heating settles in the reaction medium pulls the components back to their original states more than pushes than to the converted equilibrium state of the matter.

Biodiesel production process intensification using a rotor-stator type generator of hydrodynamic cavitation.

PubMed

Crudo, Daniele; Bosco, Valentina; Cavaglià, Giuliano; Grillo, Giorgio; Mantegna, Stefano; Cravotto, Giancarlo

2016-11-01

Triglyceride transesterification for biodiesel production is a model reaction which is used to compare the conversion efficiency, yield, reaction time, energy consumption, scalability and cost estimation of different reactor technology and energy source. This work describes an efficient, fast and cost-effective procedure for biodiesel preparation using a rotating generator of hydrodynamic cavitation (HC). The base-catalyzed transesterification (methanol/sodium hydroxide) has been carried out using refined and bleached palm oil and waste vegetable cooking oil. The novel HC unit is a continuous rotor-stator type reactor in which reagents are directly fed into the controlled cavitation chamber. The high-speed rotation of the reactor creates micron-sized droplets of the immiscible reacting mixture leading to outstanding mass and heat transfer and enhancing the kinetics of the transesterification reaction which completes much more quickly than traditional methods. All the biodiesel samples obtained respect the ASTM standard and present fatty acid methyl ester contents of >99% m/m in both feedstocks. The electrical energy consumption of the HC reactor is 0.030kWh per L of produced crude biodiesel, making this innovative technology really quite competitive. The reactor can be easily scaled-up, from producing a few hundred to thousands of liters of biodiesel per hour while avoiding the risk of orifices clogging with oil impurities, which may occur in conventional HC reactors. Furthermore it requires minimal installation space due to its compact design, which enhances overall security. Copyright © 2016 Elsevier B.V. All rights reserved.

Preparation of biodiesel with the help of ultrasonic and hydrodynamic cavitation.

PubMed

Ji, Jianbing; Wang, Jianli; Li, Yongchao; Yu, Yunliang; Xu, Zhichao

2006-12-22

An alkali-catalyzed biodiesel production method with power ultrasonic (19.7 kHz) has been developed that allows a short reaction time and high yield because of emulsification and cavitation of the liquid-liquid immiscible system. Orthogonality experiments were employed to evaluate the effects of synthesis parameters. Furthermore, hydrodynamic cavitation was used for biodiesel production in comparison to ultrasonic method. Both methods were proved to be efficient, and time and energy saving for the preparation of biodiesel by transesterification of soybean oil.

A new hypercrosslinked supermicroporous polymer, with scope for sulfonation, and its catalytic potential for the efficient synthesis of biodiesel at room temperature.

PubMed

Bhunia, Subhajit; Banerjee, Biplab; Bhaumik, Asim

2015-03-25

We have designed a new hypercrosslinked supermicroporous polymer (HMP-1) with a BET surface area of 913 m(2) g(-1) by FeCl3 via a catalyzed Friedel-Crafts alkylation reaction between carbazole and α,α'-dibromo-p-xylene. Upon sulfonation HMP-1 yielded a very efficient solid acid catalyst for the production of biodiesels via esterification/transesterification of free fatty acids (FFA)/esters at room temperature.

Immobilized lipase from Candida sp. 99-125 on hydrophobic silicate: characterization and applications.

PubMed

Zhao, Bin; Liu, Xinlong; Jiang, Yanjun; Zhou, Liya; He, Ying; Gao, Jing

2014-08-01

Lipase Candida sp. 99-125 has been proved to be quite effective in catalyzing organic synthesis reactions and is much cheaper than commercial lipases. Mesoporous silicates are attractive materials for the immobilization of enzymes due to their unique structures. The present research designed a hydrophobic silicate with uniform pore size suitable for the comfort of lipase Candida sp. 99-125 for improving its activity and stability. The resulting immobilized lipase (LP@PMO) by adsorption was employed to catalyze hydrolysis, esterification, and transesterification reactions, and the performances were compared with the lipase immobilized on hydrophilic silicate (LP@PMS) and native lipase. The LP@PMO showed as high activity as that of native lipase in hydrolysis and much increased catalytic activity and reusability in the reactions for biodiesel production. Besides, LP@PMO also possessed better organic stability. Such results demonstrate that immobilization of lipase onto hydrophobic supports is a promising strategy to fabricate highly active and stable biocatalysts for applications.

Enzymatic production of biodiesel from Nannochloropsis gaditana lipids: Influence of operational variables and polar lipid content.

PubMed

Navarro López, Elvira; Robles Medina, Alfonso; González Moreno, Pedro A; Jiménez Callejón, María J; Esteban Cerdán, Luis; Martín Valverde, Lorena; Castillo López, Beatriz; Molina Grima, Emilio

2015-01-01

Fatty acid methyl esters (FAMEs, biodiesel) were produced from Nannochloropsis gaditana wet biomass (12% saponifiable lipids, SLs) by extraction of SLs and lipase catalyzed transesterification. Lipids were extracted by ethanol (96%)-hexane, and 31% pure SLs were obtained with 85% yield. When the lipids were degummed, SL purity increased to 95%. Novozym 435 was selected from four lipases tested. Both the lipidic composition and the use of t-butanol instead of hexane increased the reaction velocity and the conversion, since both decreased due to the adsorption of polar lipids on the lipase immobilization support. The best FAME yield (94.7%) was attained at a reaction time of 48h and using 10mL of t-butanol/g SL, 0.225gN435/g SL, 11:1 methanol/SL molar ratio and adding the methanol in three steps. In these conditions the FAME conversion decreased by 9.8% after three reaction cycles catalyzed by the same lipase batch. Copyright © 2015 Elsevier Ltd. All rights reserved.

Production of biodiesel from Jatropha curcas L. oil catalyzed by SO₄²⁻/ZrO₂ catalyst: effect of interaction between process variables.

PubMed

Yee, Kian Fei; Lee, Keat Teong; Ceccato, Riccardo; Abdullah, Ahmad Zuhairi

2011-03-01

This study reports the conversion of Jatrophacurcas L. oil to biodiesel catalyzed by sulfated zirconia loaded on alumina catalyst using response surface methodology (RSM), specifically to study the effect of interaction between process variables on the yield of biodiesel. The transesterification process variables studied were reaction temperature, reaction duration, molar ratio of methanol to oil and catalyst loading. Results from this study revealed that individual as well as interaction between variables significantly affect the yield of biodiesel. With this information, it was found that 4h of reaction at 150°C, methanol to oil molar ratio of 9.88 mol/mol and 7.61 wt.% for catalyst loading gave an optimum biodiesel yield of 90.32 wt.%. The fuel properties of Jatropha biodiesel were characterized and it indeed met the specification for biodiesel according to ASTM D6751. Copyright © 2010 Elsevier Ltd. All rights reserved.

Green polymer chemistry: The role of Candida antarctica lipase B in polymer functionalization

NASA Astrophysics Data System (ADS)

Castano Gil, Yenni Marcela

The synthesis of functional polymers with well-defined structure, end-group fidelity and physico-chemical properties useful for biomedical applications has proven challenging. Chemo-enzymatic methods are an alternative strategy to increase the diversity of functional groups in polymeric materials. Specifically, enzyme-catalyzed polymer functionalization carried out under solventless conditions is a great advancement in the design of green processes for biomedical applications, where the toxicity of solvents and catalyst residues need to be considered. Enzymes offer several distinct advantages, including high efficiency, catalyst recyclability, and mild reaction conditions. This reseach aimed to precisely functionalized polymers using two methods: enzyme-catalyzed functionalization via polymerization and chemo-enzymatic functionalization of pre-made polymers for drug delivery. In the first method, well-defined poly(caprolactone)s were generated using alkyne-based initiating systems catalyzed by CALB. Propargyl alcohol and 4-dibenzocyclooctynol (DIBO) were shown to efficiently initiate the ring opening polymerization of epsilon-caprolactone under metal free conditions and yielded polymers with Mn ~4 to 24 KDa and relatively narrow molecular mass distribution. In the second methodology, we present quantitative enzyme-catalyzed transesterification of vinyl esters and ethyl esters with poly(ethylene glycol)s (PEG)s that will serve as building blocks for dendrimer synthesis, followed by introducing a new process for the exclusive gamma-conjugation of folic acid. Specifically, fluorescein-acrylate was enzymatically conjugated with PEG. Additionally, halo-ester functionalized PEGs were successfully prepared by the transesterification of alkyl halo-esters with PEGs. 1H and 13C NMR spectroscopy, SEC and MALDI-ToF mass spectrometry confirmed the structure and purity of the products.

Transesterification of waste vegetable oil under pulse sonication using ethanol, methanol and ethanol-methanol mixtures.

PubMed

Martinez-Guerra, Edith; Gude, Veera Gnaneswar

2014-12-01

This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, and ethanol-methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol-methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1-2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol-methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Lipase-catalyzed simultaneous biosynthesis of biodiesel and glycerol carbonate from corn oil in dimethyl carbonate.

PubMed

Min, Ji Young; Lee, Eun Yeol

2011-09-01

Biodiesel [fatty acid methyl esters (FAMEs)] and glycerol carbonate were synthesized from corn oil and dimethyl carbonate (DMC) via transesterification using lipase (Novozyme 435) in solvent-free reaction in which excess DMC was used as the substrate and reaction medium. Glycerol carbonate was also simultaneously formed from DMC and glycerol. Conversions of FAMEs and glycerol carbonate were examined in batch reactions. The FAMEs and glycerol carbonate reached 94 and 62.5% from oil and DMC (molar ratio of 1:10) with 0.2% (v/v) water and 10% (w/w) Novozyme 435 (based on oil weight) at 60 °C. When Novozyme 435 was washed with acetone after each reaction, more than 80% activity still remained after seven recycling. © Springer Science+Business Media B.V. 2011

Development of a millimetrically scaled biodiesel transesterification device that relies on droplet-based co-axial fluidics

NASA Astrophysics Data System (ADS)

Yeh, S. I.; Huang, Y. C.; Cheng, C. H.; Cheng, C. M.; Yang, J. T.

2016-07-01

In this study, we investigated a fluidic system that adheres to new concepts of energy production. To improve efficiency, cost, and ease of manufacture, a millimetrically scaled device that employs a droplet-based co-axial fluidic system was devised to complete alkali-catalyzed transesterification for biodiesel production. The large surface-to-volume ratio of the droplet-based system, and the internal circulation induced inside the moving droplets, significantly enhanced the reaction rate of immiscible liquids used here - soybean oil and methanol. This device also decreased the molar ratio between methanol and oil to near the stoichiometric coefficients of a balanced chemical equation, which enhanced the total biodiesel volume produced, and decreased the costs of purification and recovery of excess methanol. In this work, the droplet-based co-axial fluidic system performed better than other methods of continuous-flow production. We achieved an efficiency that is much greater than that of reported systems. This study demonstrated the high potential of droplet-based fluidic chips for energy production. The small energy consumption and low cost of the highly purified biodiesel transesterification system described conforms to the requirements of distributed energy (inexpensive production on a moderate scale) in the world.

Production of Fatty Acid Methyl Esters via the In Situ Transesterification of Soybean Oil in Carbon Dioxide-Expanded Methanol

USDA-ARS?s Scientific Manuscript database

The production of fatty acid methyl esters (FAME) by direct alkali- and acid-catalyzed in situ transesterification of soybean flakes in CO2-expanded methanol was examined at various temperatures and pressures. Attempts to synthesize FAME from soy flakes via alkaline catalysis, using sodium methoxid...

RNA catalysis and the origins of life

NASA Technical Reports Server (NTRS)

Orgel, Leslie E.

1986-01-01

The role of RNA catalysis in the origins of life is considered in connection with the discovery of riboszymes, which are RNA molecules that catalyze sequence-specific hydrolysis and transesterification reactions of RNA substrates. Due to this discovery, theories positing protein-free replication as preceding the appearance of the genetic code are more plausible. The scope of RNA catalysis in biology and chemistry is discussed, and it is noted that the development of methods to select (or predict) RNA sequences with preassigned catalytic functions would be a major contribution to the study of life's origins.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martinez-Guerra, Edith; Gude, Veera Gnaneswar, E-mail: gude@cee.msstate.edu

Highlights: • Pulse sonication effect on transesterification of waste vegetable oil was studied. • Effects of ethanol, methanol, and alcohol mixtures on FAMEs yield were evaluated. • Effect of ultrasonic intensity, power density, and its output rates were evaluated. • Alcohol mixtures resulted in higher biodiesel yields due to better solubility. - Abstract: This study reports on the effects of direct pulse sonication and the type of alcohol (methanol and ethanol) on the transesterification reaction of waste vegetable oil without any external heating or mechanical mixing. Biodiesel yields and optimum process conditions for the transesterification reaction involving ethanol, methanol, andmore » ethanol–methanol mixtures were evaluated. The effects of ultrasonic power densities (by varying sample volumes), power output rates (in W), and ultrasonic intensities (by varying the reactor size) were studied for transesterification reaction with ethanol, methanol and ethanol–methanol (50%-50%) mixtures. The optimum process conditions for ethanol or methanol based transesterification reaction of waste vegetable oil were determined as: 9:1 alcohol to oil ratio, 1% wt. catalyst amount, 1–2 min reaction time at a power output rate between 75 and 150 W. It was shown that the transesterification reactions using ethanol–methanol mixtures resulted in biodiesel yields as high as >99% at lower power density and ultrasound intensity when compared to ethanol or methanol based transesterification reactions.« less

Evaluation of malt spent rootlets biochar as catalyst for biodiesel production.

NASA Astrophysics Data System (ADS)

Pantiora, Dimitra

2014-05-01

Evaluation of malt spent rootlets biochar as catalyst for biodiesel production. Dimitra Pantiora1, Hrissi K. Karapanagioti1, Ioannis D. Manariotis2, Alexis Lycourghiotis1, Christos Kordulis1,3 (1) University of Patras, Department of Chemistry, GR 26500, Patras, Greece, (2) University of Patras, Department of Civil Engineering, Patras, Greece, (3) Institute of Chemical Engineering Science (FORTH/ ICE-HT), Stadiou Str., Platani, GR 26500, Patras, Greece Biodiesel is an attractive renewable fuel, environmentally friendly, and can readily be synthesized from the triglycerides found in animal fats and vegetable oils. It can be used in existing engines. Biodiesel consists of fatty acid alkyl esters. Conversion of triglycerides to biodiesel fuel is commonly achieved through a series of transesterification reactions involving the reaction of an alkoxy group of an ester (i.e., mono-, di-, or triglyceride) with that of a small alcohol (usually methanol). This reaction is traditionally catalyzed by homogeneous catalysts, such as bases or mineral acids. Basic catalysts have been proved to be much more active than acidic ones. However, due to environmental (waste water) and economic concerns (catalyst separation and product and by-product cleaning), heterogeneous catalysts are much more desirable. In the present study we have evaluated the use of biochar, produced from malt spent rootlets, as a potential basic catalyst, for transesterification of triglycerides using triacetin as a probe molecule. The biochar used in this study was prepared by heating malt spent rootlets in an oxygen-limited environment. It is a carbon rich material, containing 66% C, 22% O, 0.45% Mg, 0.86% Si, 5.7% K, 1.5% Cl, 0.61% Ca, and 2.4% P. Aqueous suspension of this material equilibrates at pH= 10. This is probably due to high K content. Furthermore, it exhibits high specific surface area (SSA= 183 m2g-1). The above described characteristics make this material very promising catalyst for transesterification reactions. Indeed, the corresponding catalytic tests showed that 100% transesterification of triacetin can be achieved into 0.5 hour. This activity was maintained at least for 4 successive catalytic runs.

Homogeneous, heterogeneous and enzymatic catalysis for transesterification of high free fatty acid oil (waste cooking oil) to biodiesel: a review.

PubMed

Lam, Man Kee; Lee, Keat Teong; Mohamed, Abdul Rahman

2010-01-01

In the last few years, biodiesel has emerged as one of the most potential renewable energy to replace current petrol-derived diesel. It is a renewable, biodegradable and non-toxic fuel which can be easily produced through transesterification reaction. However, current commercial usage of refined vegetable oils for biodiesel production is impractical and uneconomical due to high feedstock cost and priority as food resources. Low-grade oil, typically waste cooking oil can be a better alternative; however, the high free fatty acids (FFA) content in waste cooking oil has become the main drawback for this potential feedstock. Therefore, this review paper is aimed to give an overview on the current status of biodiesel production and the potential of waste cooking oil as an alternative feedstock. Advantages and limitations of using homogeneous, heterogeneous and enzymatic transesterification on oil with high FFA (mostly waste cooking oil) are discussed in detail. It was found that using heterogeneous acid catalyst and enzyme are the best option to produce biodiesel from oil with high FFA as compared to the current commercial homogeneous base-catalyzed process. However, these heterogeneous acid and enzyme catalyze system still suffers from serious mass transfer limitation problems and therefore are not favorable for industrial application. Nevertheless, towards the end of this review paper, a few latest technological developments that have the potential to overcome the mass transfer limitation problem such as oscillatory flow reactor (OFR), ultrasonication, microwave reactor and co-solvent are reviewed. With proper research focus and development, waste cooking oil can indeed become the next ideal feedstock for biodiesel.

Beauveria bassiana Lipase A expressed in Komagataella (Pichia) pastoris with potential for biodiesel catalysis.

PubMed

Vici, Ana C; da Cruz, Andrezza F; Facchini, Fernanda D A; de Carvalho, Caio C; Pereira, Marita G; Fonseca-Maldonado, Raquel; Ward, Richard J; Pessela, Benevides C; Fernandez-Lorente, Gloria; Torres, Fernando A G; Jorge, João A; Polizeli, Maria L T M

2015-01-01

Lipases (EC 3.1.1.3) comprise a biotechnologically important group of enzymes because they are able to catalyze both hydrolysis and synthesis reactions, depending on the amount of water in the system. One of the most interesting applications of lipase is in the biofuel industry for biodiesel production by oil and ethanol (or methanol) transesterification. Entomopathogenic fungi, which are potential source of lipases, are still poorly explored in biotechnological processes. The present work reports the heterologous expression and biochemical characterization of a novel Beauveria bassiana lipase with potential for biodiesel production. The His-tagged B. bassiana lipase A (BbLA) was produced in Komagataella pastoris in buffered methanol medium (BMM) induced with 1% methanol at 30°C. Purified BbLA was activated with 0.05% Triton X-100 and presented optimum activity at pH 6.0 and 50°C. N-glycosylation of the recombinant BbLA accounts for 31.5% of its molecular weight. Circular dichroism and molecular modeling confirmed a structure composed of α-helix and β-sheet, similar to α/β hydrolases. Immobilized BbLA was able to promote transesterification reactions in fish oil, demonstrating potential for biodiesel production. BbLA was successfully produced in K. pastoris and shows potential use for biodiesel production by the ethanolysis reaction.

Beauveria bassiana Lipase A expressed in Komagataella (Pichia) pastoris with potential for biodiesel catalysis

PubMed Central

Vici, Ana C.; da Cruz, Andrezza F.; Facchini, Fernanda D. A.; de Carvalho, Caio C.; Pereira, Marita G.; Fonseca-Maldonado, Raquel; Ward, Richard J.; Pessela, Benevides C.; Fernandez-Lorente, Gloria; Torres, Fernando A. G.; Jorge, João A.; Polizeli, Maria L. T. M.

2015-01-01

Lipases (EC 3.1.1.3) comprise a biotechnologically important group of enzymes because they are able to catalyze both hydrolysis and synthesis reactions, depending on the amount of water in the system. One of the most interesting applications of lipase is in the biofuel industry for biodiesel production by oil and ethanol (or methanol) transesterification. Entomopathogenic fungi, which are potential source of lipases, are still poorly explored in biotechnological processes. The present work reports the heterologous expression and biochemical characterization of a novel Beauveria bassiana lipase with potential for biodiesel production. The His-tagged B. bassiana lipase A (BbLA) was produced in Komagataella pastoris in buffered methanol medium (BMM) induced with 1% methanol at 30°C. Purified BbLA was activated with 0.05% Triton X-100 and presented optimum activity at pH 6.0 and 50°C. N-glycosylation of the recombinant BbLA accounts for 31.5% of its molecular weight. Circular dichroism and molecular modeling confirmed a structure composed of α-helix and β-sheet, similar to α/β hydrolases. Immobilized BbLA was able to promote transesterification reactions in fish oil, demonstrating potential for biodiesel production. BbLA was successfully produced in K. pastoris and shows potential use for biodiesel production by the ethanolysis reaction. PMID:26500628

Lipase-catalyzed kinetic resolution of novel antitubercular benzoxazole derivatives.

PubMed

Łukowska-Chojnacka, Edyta; Kowalkowska, Anna; Napiórkowska, Agnieszka

2018-04-01

Novel benzoxazole derivatives were synthesized, and their antitubercular activity against sensitive and drug-resistant Mycobacterium tuberculosis strains (M. tuberculosis H 37 Rv, M. tuberculosis sp. 210, M. tuberculosis sp. 192, Mycobacterium scrofulaceum, Mycobacterium intracellulare, Mycobacterium fortuitum, Mycobacterium avium, and Mycobacterium kansasii) was evaluated. The chemical step included preparation of ketones, alcohols, and esters bearing benzoxazole moiety. All racemic mixtures of alcohols and esters were separated in Novozyme SP 435-catalyzed transesterification and hydrolysis, respectively. The transesterification reactions were carried out in various organic solvents (tert-butyl methyl ether, toluene, diethyl ether, and diisopropyl ether), and depending on the solvent, the enantioselectivity of the reactions ranged from 4 to >100. The enzymatic hydrolysis of esters was performed in 2 phase tert-butyl methyl ether/phosphate buffer (pH = 7.2) system and provided also enantiomerically enriched products (ee 88-99%). The antitubercular activity assay has shown that synthesized compounds exhibit an interesting antitubercular activity. Racemic mixtures of alcohols, (±)-4-(1,3-benzoxazol-2-ylsulfanyl)butan-2-ol ((±)-3a), (±)-4-[(5-bromo-1,3-benzoxazol-2-yl)sulfanyl]butan-2-ol ((±)-3b), and (±)-4-[(5,7-dibromo-1,3-benzoxazol-2-yl)sulfanyl]butan-2-ol ((±)-3c), displayed as high activity against M. scrofulaceum, M. intracellulare, M. fortuitum, and M. kansasii as commercially available antituberculosis drug-Isoniazid. Moreover, these compounds exhibited twice higher activity toward M. avium (MIC 12.5) compared with Isoniazid (MIC 50). © 2017 Wiley Periodicals, Inc.

Highly efficient conversion of plant oil to bio-aviation fuel and valuable chemicals by combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating.

PubMed

Wang, Meng; Chen, Mojin; Fang, Yunming; Tan, Tianwei

2018-01-01

The production of fuels and chemicals from renewable resources is increasingly important due to the environmental concern and depletion of fossil fuel. Despite the fast technical development in the production of aviation fuels, there are still several shortcomings such as a high cost of raw materials, a low yield of aviation fuels, and poor process techno-economic consideration. In recent years, olefin metathesis has become a powerful and versatile tool for generating new carbon-carbon bonds. The cross-metathesis reaction, one kind of metathesis reaction, has a high potential to efficiently convert plant oil into valuable chemicals, such as α-olefin and bio-aviation fuel by combining with a hydrotreatment process. In this research, an efficient, four-step conversion of plant oil into bio-aviation fuel and valuable chemicals was developed by the combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreating. Firstly, plant oil including oil with poor properties was esterified to fatty acid methyl esters by an enzyme-catalyzed process. Secondly, the fatty acid methyl esters were partially hydrotreated catalytically to transform poly-unsaturated fatty acid such as linoleic acid into oleic acid. The olefin cross-metathesis then transformed the oleic acid methyl ester (OAME) into 1-decene and 1-decenoic acid methyl ester (DAME). The catalysts used in this process were prepared/selected in function of the catalytic reaction and the reaction conditions were optimized. The carbon efficiency analysis of the new process illustrated that it was more economically feasible than the traditional hydrotreatment process. A highly efficient conversion process of plant oil into bio-aviation fuel and valuable chemicals by the combination of enzymatic transesterification, olefin cross-metathesis, and hydrotreatment with prepared and selected catalysts was designed. The reaction conditions were optimized. Plant oil was transformed into bio-aviation fuel and a high value α-olefin product with high carbon utilization.

Synthesis of structured lipids by transesterification of trilinolein catalyzed by Lipozyme IM60.

PubMed

Sellappan, S; Akoh, C C

2001-04-01

Structured lipids (SL) containing caprylic, stearic, and linoleic acids were synthesized by enzymatic transesterification using Lipozyme IM60. Pure trilinolein and free fatty acids were used as substrates. Incorporation of stearic acid was higher than that of caprylic acid in all parameters. Highest incorporations of both acids were achieved at 32 h, mole ratio of 1:4:4 (trilinolein/caprylic/stearic acids), water content of 1% (wt %), temperature of 55 degrees C, and 10% (wt %) enzyme load. The maximal incorporations of caprylic and stearic acids were 23.73 and 62.46 mol %, respectively. Reaction time, water content, and enzyme load had major influences on the reaction, whereas substrate mole ratio and temperature showed less influence. Lipozyme showed good stability over six reuses. Differential scanning calorimetric analysis of SL gave a melting profile with a very low melting peak of 0-3.3 degrees C and a solid fat content of 25.21% at 0 degrees C. The melting profile and solid fat content of SL were compared with those of fats extracted from commercially available solid and liquid margarine products. The data suggest that enzymatically produced SL could be used in liquid margarine products.

Alginate as immobilization matrix and stabilizing agent in a two-phase liquid system: application in lipase-catalysed reactions.

PubMed

Hertzberg, S; Kvittingen, L; Anthonsen, T; Skjåk-Braek, G

1992-01-01

Alginate was evaluated as an immobilization matrix for enzyme-catalyzed reactions in organic solvents. In contrast to most hydrogels, calcium alginate was found to be stable in a range of organic solvents and to retain the enzyme inside the gel matrix. In hydrophobic solvents, the alginate gel (greater than 95% water) thus provided a stable, two-phase liquid system. The lipase from Candida cylindracea, after immobilization in alginate beads, catalysed esterification and transesterification in n-hexane under both batch and continuous-flow conditions. The operational stability of the lipase was markedly enhanced by alginate entrapment. In the esterification of butanoic acid with n-butanol, better results were obtained in the typical hydrophilic calcium alginate beads than in less hydrophilic matrices. The effects of substrate concentration, matrix area, and polarity of the substrate alcohols and of the organic solvent on the esterification activity were examined. The transesterification of octyl 2-bromopropanoate with ethanol was less efficient than that of ethyl 2-bromopropanoate with octanol. By using the hydrophilic alginate gel as an immobilization matrix in combination with a mobile hydrophobic phase, a two-phase liquid system was achieved with definite advantages for a continuous, enzyme-catalysed process.

Biocatalytic Synthesis of Epoxy Resins from Fatty Acids as a Versatile Route for the Formation of Polymer Thermosets with Tunable Properties.

PubMed

Torron, Susana; Semlitsch, Stefan; Martinelle, Mats; Johansson, Mats

2016-12-12

The work herein presented describes the synthesis and polymerization of series of bio-based epoxy resins prepared through lipase catalyzed transesterification. The epoxy-functional polyester resins with various architectures (linear, tri-branched, and tetra-branched) were synthesized through condensation of fatty acids derived from epoxidized soybean oil and linseed oil with three different hydroxyl cores under bulk conditions. The selectivity of the lipases toward esterification/transesterification reactions allowed the formation of macromers with up to 12 epoxides in the backbone. The high degree of functionality of the resins resulted in polymer thermosets with T g values ranging from -25 to over 100 °C prepared through cationic polymerization. The determining parameters of the synthesis and the mechanism for the formation of the species were determined through kinetic studies by 1 H NMR, SEC, and molecular modeling studies. The correlation between macromer structure and thermoset properties was studied through real-time FTIR measurements, DSC, and DMA.

Rapid synthesis of propyl caffeate in ionic liquid using a packed bed enzyme microreactor under continuous-flow conditions.

PubMed

Wang, Jun; Gu, Shuang-Shuang; Cui, Hong-Sheng; Yang, Liu-Qing; Wu, Xiang-Yang

2013-12-01

Propyl caffeate has the highest antioxidant activity among caffeic acid alkyl esters, but its industrial production via enzymatic transesterification in batch reactors is hindered by a long reaction time (24h). To develop a rapid process for the production of propyl caffeate in high yield, a continuous-flow microreactor composed of a two-piece PDMS in a sandwich-like microchannel structure was designed for the transesterification of methyl caffeate and 1-propanol catalyzed by Novozym 435 in [B mim][CF3SO3]. The maximum yield (99.5%) in the microreactor was achieved in a short period of time (2.5h) with a flow rate of 2 μL/min, which kinetic constant Km was 16 times lower than that of a batch reactor. The results indicated that the use of a continuous-flow packed bed enzyme microreactor is an efficient method of producing propyl caffeate with an overall yield of 84.0%. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development of a millimetrically scaled biodiesel transesterification device that relies on droplet-based co-axial fluidics

PubMed Central

Yeh, S. I.; Huang, Y. C.; Cheng, C. H.; Cheng, C. M.; Yang, J. T.

2016-01-01

In this study, we investigated a fluidic system that adheres to new concepts of energy production. To improve efficiency, cost, and ease of manufacture, a millimetrically scaled device that employs a droplet-based co-axial fluidic system was devised to complete alkali-catalyzed transesterification for biodiesel production. The large surface-to-volume ratio of the droplet-based system, and the internal circulation induced inside the moving droplets, significantly enhanced the reaction rate of immiscible liquids used here – soybean oil and methanol. This device also decreased the molar ratio between methanol and oil to near the stoichiometric coefficients of a balanced chemical equation, which enhanced the total biodiesel volume produced, and decreased the costs of purification and recovery of excess methanol. In this work, the droplet-based co-axial fluidic system performed better than other methods of continuous-flow production. We achieved an efficiency that is much greater than that of reported systems. This study demonstrated the high potential of droplet-based fluidic chips for energy production. The small energy consumption and low cost of the highly purified biodiesel transesterification system described conforms to the requirements of distributed energy (inexpensive production on a moderate scale) in the world. PMID:27426677

Biodegradable products by lipase biocatalysis.

PubMed

Linko, Y Y; Lämsä, M; Wu, X; Uosukainen, E; Seppälä, J; Linko, P

1998-11-18

The interest in the applications of biocatalysis in organic syntheses has rapidly increased. In this context, lipases have recently become one of the most studied groups of enzymes. We have demonstrated that lipases can be used as biocatalyst in the production of useful biodegradable compounds. A number of examples are given. 1-Butyl oleate was produced by direct esterification of butanol and oleic acid to decrease the viscosity of biodiesel in winter use. Enzymic alcoholysis of vegetable oils without additional organic solvent has been little investigated. We have shown that a mixture of 2-ethyl-1-hexyl esters can be obtained in a good yield by enzymic transesterification from rapeseed oil fatty acids for use as a solvent. Trimethylolpropane esters were also similarly synthesized as lubricants. Finally, the discovery that lipases can also catalyze ester syntheses and transesterification reactions in organic solvent systems has opened up the possibility of enzyme catalyzed production of biodegradable polyesters. In direct polyesterification of 1,4-butanediol and sebacic acid, polyesters with a mass average molar mass of the order of 56,000 g mol-1 or higher, and a maximum molar mass of about 130,000 g mol-1 were also obtained by using lipase as biocatalyst. Finally, we have demonstrated that also aromatic polyesters can be synthesized by lipase biocatalysis, a higher than 50,000 g mol-1 mass average molar mass of poly(1,6-hexanediyl isophthalate) as an example.

A Multidimensional B-Spline Correction for Accurate Modeling Sugar Puckering in QM/MM Simulations.

PubMed

Huang, Ming; Dissanayake, Thakshila; Kuechler, Erich; Radak, Brian K; Lee, Tai-Sung; Giese, Timothy J; York, Darrin M

2017-09-12

The computational efficiency of approximate quantum mechanical methods allows their use for the construction of multidimensional reaction free energy profiles. It has recently been demonstrated that quantum models based on the neglect of diatomic differential overlap (NNDO) approximation have difficulty modeling deoxyribose and ribose sugar ring puckers and thus limit their predictive value in the study of RNA and DNA systems. A method has been introduced in our previous work to improve the description of the sugar puckering conformational landscape that uses a multidimensional B-spline correction map (BMAP correction) for systems involving intrinsically coupled torsion angles. This method greatly improved the adiabatic potential energy surface profiles of DNA and RNA sugar rings relative to high-level ab initio methods even for highly problematic NDDO-based models. In the present work, a BMAP correction is developed, implemented, and tested in molecular dynamics simulations using the AM1/d-PhoT semiempirical Hamiltonian for biological phosphoryl transfer reactions. Results are presented for gas-phase adiabatic potential energy surfaces of RNA transesterification model reactions and condensed-phase QM/MM free energy surfaces for nonenzymatic and RNase A-catalyzed transesterification reactions. The results show that the BMAP correction is stable, efficient, and leads to improvement in both the potential energy and free energy profiles for the reactions studied, as compared with ab initio and experimental reference data. Exploration of the effect of the size of the quantum mechanical region indicates the best agreement with experimental reaction barriers occurs when the full CpA dinucleotide substrate is treated quantum mechanically with the sugar pucker correction.

Optimization of technological conditions for one-pot synthesis of (S)-alpha-cyano-3-phenoxybenzyl acetate in organic media.

PubMed

Zhang, Ting-Zhou; Yang, Li-Rong; Zhu, Zi-Qiang

2005-03-01

Optically active form of alpha-cyano-3-phenoxybenzyl (CPB) alcohol, building block of pyrethroid insecticides, was synthesized as its acetate by the combination of anion-exchange resin (D301)-catalyzed transcyanation between m-phenoxybenzaldehyde (m-PBA) and acetone cyanohydrin (AC), and lipase (from Alcaligenes sp.)-catalyzed enantioselective transesterification of the resulting cyanohydrin with vinyl acetate. Through optimizing technological conditions, the catalyzing efficiency was improved considerably compared to methods previously reported. Concentrations of CPB acetate were determined by gas chromatograph. The enantio excess (e.e.) values of CPB acetate were measured by NMR (nuclear magnetic resonance) method. Effects of solvents and temperatures on this reaction were studied. Cyclohexane was shown to be the best solvent among the three tested solvents. 55 degrees C was the optimal temperature for higher degree of conversion. External diffusion limitation was excluded by raising the rotational speed to 220 r/min. However, internal diffusion could not be ignored, since the catalyst (lipase) was an immobilized enzyme and its particle dimension was not made small enough. The reaction rate was substantially accelerated when the reactant (m-PBA) concentration was as high as 249 mmol/L, but decreased when the initial concentration of m-PBA reached to 277 mmol/L. It was also found that the catalyzing capability of recovered lipase was high enough to use several batches. Study of the mole ratio of AC to m-PBA showed that 2:1 was the best choice. The strategy of adding base catalyst D301 was found to be an important factor in improving the degree of conversion of the reaction from 20% to 80%. The highest degree of conversion of the reaction has reached up to 80%.

Optimized synthesis of lipase-catalyzed hexyl acetate in n-hexane by response surface methodology.

PubMed

Shieh, C J; Chang, S W

2001-03-01

Hexyl acetate, a short-chain ester with fruity odor, is a significant green note flavor compound and widely used in the food industry. The ability for immobilized lipase from Mucor miehei (Lipozyme IM-77) to catalyze the transesterification of hexanol with triacetin was investigated in this study. Response surface methodology and five-level-five-factor central composite rotatable design were adopted to evaluate the effects of synthesis variables, such as reaction time (2-10 h), temperature (25-65 degrees C), enzyme amount (10-50%; 0.024-0.118 BAUN), substrate molar ratio of triacetin to hexanol (1:1 to 3:1), and added water content (0-20%) on percentage molar conversion of hexyl acetate. The results showed that reaction temperature and substrate molar ratio were the most important parameters and that added water content had less of an effect on percent molar conversion. On the basis of canonical analysis, optimum synthesis conditions were as follows: reaction time, 7.7 h; temperature, 52.6 degrees C; enzyme amount, 37.1% (0.089 BAUN); substrate molar ratio, 2.7:1; and added water, 12.5%. The predicted value was 88.9% molar conversion, and the actual experimental value was 86.6% molar conversion.

Characterization of a tannase from Emericella nidulans immobilized on ionic and covalent supports for propyl gallate synthesis.

PubMed

Gonçalves, Heloísa Bressan; Jorge, João Atílio; Pessela, Benevides Costa; Lorente, Glória Fernandez; Guisán, José Manuel; Guimarães, Luis Henrique Souza

2013-04-01

The extracellular tannase from Emericela nidulans was immobilized on different ionic and covalent supports. The derivatives obtained using DEAE-Sepharose and Q-Sepharose were thermally stable from 60 to 75 °C, with a half life (t50) >24 h at 80 °C at pH 5.0. The glyoxyl-agarose and amino-glyoxyl derivatives showed a thermal stability which was lower than that observed for ionic supports. However, when the stability to pH was considered, the derivatives obtained from covalent supports were more stable than those obtained from ionic supports. DEAE-Sepharose and Q-Sepharose derivatives as well as the free enzyme were stable in 30 and 50 % (v/v) 1-propanol. The CNBr-agarose derivative catalyzed complete tannic acid hydrolysis, whereas the Q-Sepharose derivative catalyzed the transesterification reaction to produce propyl gallate (88 % recovery), which is an important antioxidant.

Ultrasonication aided in-situ transesterification of microbial lipids to biodiesel.

PubMed

Zhang, Xiaolei; Yan, Song; Tyagi, Rajeshwar Dayal; Surampalli, Rao Y; Valéro, Jose R

2014-10-01

In-situ transesterification of microbial lipid to biodiesel has been paid substantial attention due to the fact that the lipid extraction and transesterification can be conducted in one-stage process. To improve the feasibility of in-situ transesterification, ultrasonication was employed to reduce methanol requirement and reaction time. The results showed that the use of ultrasonication could achieve high conversion of lipid to FAMEs (92.1% w lipid conversion/w total lipids) with methanol to lipid molar ratio 60:1 and NaOH addition 1% w/w lipid in 20 min, while methanol to lipid molar ratio 360:1, NaOH addition 1% w/w lipid, and reaction time 12h was required to obtain similar yield in in-situ transesterification without ultrasonication. The compositions of FAMEs obtained in case of ultrasonication aided in-situ transesterification were similar as that of two-stage extraction followed by transesterification processes. Copyright © 2014. Published by Elsevier Ltd.

Synthesis of DHA/EPA-rich phosphatidylcholine by immobilized phospholipase A1: effect of water addition and vacuum condition.

PubMed

Li, Daoming; Qin, Xiaoli; Wang, Weifei; Li, Zhigang; Yang, Bo; Wang, Yonghua

2016-08-01

DHA/EPA-rich phosphatidylcholine (PC) was successfully synthesized by immobilized phospholipase A1 (PLA1)-catalyzed transesterification of PC and DHA/EPA-rich ethyl esters in a solvent-free system. Effects of reaction temperature, water addition and substrate mass ratio on the incorporation of DHA/EPA were evaluated using response surface methods (RSM). Water addition had most significant effect on the incorporation. Reaction temperature and substrate mass ratio, however, had no significant effect on the incorporation. The maximal incorporation was 19.09 % (24 h) under the following conditions: temperature 55.7 °C, water addition 1.1 wt % and substrate mass ratio (ethyl esters/PC) 6.8:1. Furthermore, effects of water addition (from 0 to 1.25 wt %) on DHA/EPA incorporation and the composition of products were further investigated. The immobilized PLA1 was more active when water addition was above 0.5 wt %. By monitoring the reaction processes with different water addition, a possible reaction scheme was proposed for transesterification of PC with DHA/EPA-rich ethyl esters. In summary, PC and sn2-lysophosphatidylocholine (LPC) were predominant in the mixtures at early stages of reaction, whereas sn1-LPC and glycerophosphocholine (GPC) predominant at later stages. The vacuum employed after 24 h significantly increased the incorporation of DHA/EPA and the composition of PC, and the highest incorporation (30.31 %) of DHA/EPA was obtained at 72 h and the yield of PC was 47.2 %.

Optimization of lipase-catalyzed biodiesel by isopropanolysis in a continuous packed-bed reactor using response surface methodology.

PubMed

Chang, Cheng; Chen, Jiann-Hwa; Chang, Chieh-Ming J; Wu, Tsung-Ta; Shieh, Chwen-Jen

2009-10-31

Isopropanolysis reactions were performed using triglycerides with immobilized lipase in a solvent-free environment. This study modeled the degree of isopropanolysis of soybean oil in a continuous packed-bed reactor when Novozym 435 was used as the biocatalyst. Response surface methodology (RSM) and three-level-three-factor Box-Behnken design were employed to evaluate the effects of synthesis parameters, reaction temperature ( degrees C), flow rate (mL/min) and substrate molar ratio of isopropanol to soybean oil, on the percentage molar conversion of biodiesel by transesterification. The results show that flow rate and temperature have a significant effect on the percentage of molar conversion. On the basis of ridge max analysis, the optimum conditions for synthesis were as follows: flow rate 0.1 mL/min, temperature 51.5 degrees C and substrate molar ratio 1:4.14. The predicted value was 76.62+/-1.52% and actual experimental value was 75.62+/-0.81% molar conversion. Moreover, continuous enzymatic process for seven days did not show any appreciable decrease in the percent of molar conversion (75%). This work demonstrates the applicability of lipase catalysis to prepare isopropyl esters by transesterification in solvent-free system with a continuous packed-bed reactor for industrial production.

Radical scavenging activity of lipophilized products from lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids.

PubMed

Choo, Wee-Sim; Birch, Edward John

2009-02-01

Lipase-catalyzed transesterification of triolein with cinnamic and ferulic acids using an immobilized lipase from Candida antarctica (E.C. 3.1.1.3) was conducted to evaluate the antioxidant activity of the lipophilized products as model systems for enhanced protection of unsaturated oil. The lipophilized products were identified using ESI-MS. Free radical scavenging activity was determined using the DPPH radical method. The polarity of the solvents proved important in determining the radical scavenging activity of the substrates. Ferulic acid showed much higher radical scavenging activity than cinnamic acid, which has limited activity. The esterification of cinnamic acid and ferulic acid with triolein resulted in significant increase and decrease in the radical scavenging activity, respectively. These opposite effects were due to the effect of addition of electron-donating alkyl groups on the predominant mechanism of reaction (hydrogen atom transfer or electron transfer) of a species with DPPH. The effect of esterification of cinnamic acid was confirmed using ethyl cinnamate which greatly enhances the radical scavenging activity. Although, compared to the lipophilized cinnamic acid product, the activity was lower. The radical scavenging activity of the main component isolated from lipophilized cinnamic acid product using solid phase extraction, monocinnamoyl dioleoyl glycerol, was as good as the unseparated mixture of lipophilized product. Based on the ratio of a substrate to DPPH concentration, lipophilized ferulic acid was a much more efficient radical scavenger than lipophilized cinnamic acid.

Biodiesel production by direct transesterification of microalgal biomass with co-solvent.

PubMed

Zhang, Yan; Li, Ya; Zhang, Xu; Tan, Tianwei

2015-11-01

In this study, a direct transesterification process using 75% ethanol and co-solvent was studied to reduce the energy consumption of lipid extraction process and improve the conversion yield of the microalgae biodiesel. The addition of a certain amount of co-solvent (n-hexane is most preferable) was required for the direct transesterification of microalgae biomass. With the optimal reaction condition of n-hexane to 75% ethanol volume ratio 1:2, mixed solvent dosage 6.0mL, reaction temperature 90°C, reaction time 2.0h and catalyst volume 0.6mL, the direct transesterification process of microalgal biomass resulted in a high conversion yield up to 90.02±0.55wt.%. Copyright © 2015 Elsevier Ltd. All rights reserved.

Efficient solvothermal wet in situ transesterification of Nannochloropsis gaditana for biodiesel production.

PubMed

Kim, Bora; Chang, Yong Keun; Lee, Jae W

2017-05-01

In situ transesterification of wet microalgae is a promising, simplified alternative biodiesel production process that replaces multiple operations of cell drying, extraction, and transesterification reaction. This study addresses enhanced biodiesel production from Nannochloropsis gaditana at elevated temperatures. Compared with the previously reported in situ transesterification process of conducting the reaction at a temperature ranging from 95 to 125 °C, the present work employs higher temperatures of at least 150 °C. This relatively harsh condition allows much less acid catalyst with or without co-solvent to be used during this single extraction-conversion process. Without any co-solvent, 0.58% (v/v) of H 2 SO 4 in the reaction medium can achieve 90 wt% of the total lipid conversion to biodiesel at 170 °C when the moisture content of wet algal paste is 80 wt%. Here, the effects of temperature, acid catalyst, and co-solvent on the FAEE yield and specification were scrutinized, and the reaction kinetic was investigated to understand the solvothermal in situ transesterification reaction at the high temperature. Having a biphasic system (water/chloroform) during the reaction also helped to meet biodiesel quality standard EN 14214, as Na + , K + , Ca 2+ , Mg 2+ cations and phosphorus were detected only below 5 ppm. With highlights on the economic feasibility, wet in situ transesterification at the high temperature can contribute to sustainable production of biodiesel from microalgae by reducing the chemical input and relieve the burden of extensive post purification process, therefore a step towards green process.

Bioremediation of cooking oil waste using lipases from wastes

PubMed Central

do Prado, Débora Zanoni; Facanali, Roselaine; Marques, Márcia Mayo Ortiz; Nascimento, Augusto Santana; Fernandes, Célio Junior da Costa; Zambuzzi, William Fernando

2017-01-01

Cooking oil waste leads to well-known environmental impacts and its bioremediation by lipase-based enzymatic activity can minimize the high cytotoxic potential. In addition, they are among the biocatalysts most commercialized worldwide due to the versatility of reactions and substrates. However, although lipases are able to process cooking oil wastes, the products generated from this process do not necessarily become less toxic. Thus, the aim of the current study is to analyze the bioremediation of lipase-catalyzed cooking oil wastes, as well as their effect on the cytotoxicity of both the oil and its waste before and after enzymatic treatment. Thus, assessed the post-frying modification in soybean oil and in its waste, which was caused by hydrolysis reaction catalyzed by commercial and home-made lipases. The presence of lipases in the extracts obtained from orange wastes was identified by zymography. The profile of the fatty acid esters formed after these reactions was detected and quantified through gas chromatography and fatty acids profile compared through multivariate statistical analyses. Finally, the soybean oil and its waste, with and without enzymatic treatment, were assessed for toxicity in cytotoxicity assays conducted in vitro using fibroblast cell culture. The soybean oil wastes treated with core and frit lipases through transesterification reaction were less toxic than the untreated oils, thus confirming that cooking oil wastes can be bioremediated using orange lipases. PMID:29073166

Bioremediation of cooking oil waste using lipases from wastes.

PubMed

Okino-Delgado, Clarissa Hamaio; Prado, Débora Zanoni do; Facanali, Roselaine; Marques, Márcia Mayo Ortiz; Nascimento, Augusto Santana; Fernandes, Célio Junior da Costa; Zambuzzi, William Fernando; Fleuri, Luciana Francisco

2017-01-01

Cooking oil waste leads to well-known environmental impacts and its bioremediation by lipase-based enzymatic activity can minimize the high cytotoxic potential. In addition, they are among the biocatalysts most commercialized worldwide due to the versatility of reactions and substrates. However, although lipases are able to process cooking oil wastes, the products generated from this process do not necessarily become less toxic. Thus, the aim of the current study is to analyze the bioremediation of lipase-catalyzed cooking oil wastes, as well as their effect on the cytotoxicity of both the oil and its waste before and after enzymatic treatment. Thus, assessed the post-frying modification in soybean oil and in its waste, which was caused by hydrolysis reaction catalyzed by commercial and home-made lipases. The presence of lipases in the extracts obtained from orange wastes was identified by zymography. The profile of the fatty acid esters formed after these reactions was detected and quantified through gas chromatography and fatty acids profile compared through multivariate statistical analyses. Finally, the soybean oil and its waste, with and without enzymatic treatment, were assessed for toxicity in cytotoxicity assays conducted in vitro using fibroblast cell culture. The soybean oil wastes treated with core and frit lipases through transesterification reaction were less toxic than the untreated oils, thus confirming that cooking oil wastes can be bioremediated using orange lipases.

Application of a chitosan-immobilized Talaromyces thermophilus lipase to a batch biodiesel production from waste frying oils.

PubMed

Romdhane, Ines Belhaj-Ben; Romdhane, Zamen Ben; Bouzid, Maha; Gargouri, Ali; Belghith, Hafedh

2013-12-01

Waste frying oil, which not only harms people's health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.

Water-soluble resist for environmentally friendly lithography

NASA Astrophysics Data System (ADS)

Lin, Qinghuang; Simpson, Logan L.; Steinhaeusler, Thomas; Wilder, Michelle; Willson, C. Grant; Havard, Jennifer M.; Frechet, Jean M. J.

1996-05-01

This paper describes an 'environmentally friendly,' water castable, water developable photoresist system. The chemically amplified negative-tone resist system consists of three water-soluble components: a polymer, poly(methyl acrylamidoglycolate methyl ether), [poly(MAGME)]; a photoacid generator, dimethyl dihydroxyphenylsulfonium triflate and a crosslinker, butanediol. Poly(MAGME) was synthesized by solution free radical polymerization. In the three-component resist system, the acid generated by photolysis of the photoacid generator catalyzes the crosslinking of poly(MAGME) in the exposed regions during post-exposure baking, thus rendering the exposed regions insoluble in water. Negative tone relief images are obtained by developing with pure water. The resist is able to resolve 1 micrometer line/space features (1:1 aspect ratio) with an exposure dose of 100 mJ/cm2 at 248 nm. The resist can be used to generate etched copper relief images on printed circuit boards using aqueous sodium persulfate as the etchant. The crosslinking mechanism has been investigated by model compound studies using 13C NMR. These studies have revealed that the acid catalyzed reaction of the poly(MAGME) with butanediol proceeds via both transesterification and transacetalization (transaminalization) reactions at low temperatures, and also via transamidation at high temperatures.

A review on lipase-catalyzed reactions in ultrasound-assisted systems.

PubMed

Lerin, Lindomar A; Loss, Raquel A; Remonatto, Daniela; Zenevicz, Mara Cristina; Balen, Manuela; Netto, Vendelino Oenning; Ninow, Jorge L; Trentin, Cláudia M; Oliveira, J Vladimir; de Oliveira, Débora

2014-12-01

The named "green chemistry" has been receiving increasing prominence due to its environmentally friendly characteristics. The use of enzymes as catalysts in processes of synthesis to replace the traditional use of chemical catalysts present as main advantage the fact of following the principles of the green chemistry. However, processes of enzymatic nature generally provide lower yields when compared to the conventional chemical processes. Therefore, in the last years, the ultrasound has been extensively used in enzymatic processes, such as the production of esters with desirable characteristics for the pharmaceutical, cosmetics, and food industry, for the hydrolysis and glycerolysis of vegetable oils, production of biodiesel, etc. Several works found in the open literature suggest that the energy released by the ultrasound during the cavitation phenomena can be used to enhance mass transfer (substrate/enzyme), hence increasing the rate of products formation, and also contributing to enhance the enzyme catalytic activity. Furthermore, the ultrasound is considered a "green" technology due to its high efficiency, low instrumental requirement and significant reduction of the processing time in comparison to other techniques. The main goal of this review was to summarize studies available to date regarding the application of ultrasound in enzyme-catalyzed esterification, hydrolysis, glycerolysis and transesterification reactions.

Role of metal ions in catalysis by HIV integrase analyzed using a quantitative PCR disintegration assay.

PubMed

Diamond, Tracy L; Bushman, Frederic D

2006-01-01

Paired metal ions have been proposed to be central to the catalytic mechanisms of RNase H nucleases, bacterial transposases, Holliday junction resolvases, retroviral integrases and many other enzymes. Here we present a sensitive assay for DNA transesterification in which catalysis by human immunodeficiency virus-type 1 (HIV-1) integrase (IN) connects two DNA strands (disintegration reaction), allowing detection using quantitative PCR (qPCR). We present evidence suggesting that the three acidic residues of the IN active site function through metal binding using metal rescue. In this method, the catalytic acidic residues were each substituted with cysteines. Mn2+ binds tightly to the sulfur atoms of the cysteine residues, but Mg2+ does not. We found that Mn2+, but not Mg2+, could rescue catalysis of each cysteine-substituted enzyme, providing evidence for functionally important metal binding by all three residues. We also used the PCR-boosted assay to show that HIV-1 IN could carry out transesterification reactions involving DNA 5' hydroxyl groups as well as 3' hydroxyls as nucleophiles. Lastly, we show that Mn2+ by itself (i.e. without enzyme) can catalyze formation of a low level of PCR-amplifiable product under extreme conditions, allowing us to estimate the rate enhancement due to the IN-protein scaffold as at least 60 million-fold.

Role of metal ions in catalysis by HIV integrase analyzed using a quantitative PCR disintegration assay

PubMed Central

Diamond, Tracy L.; Bushman, Frederic D.

2006-01-01

Paired metal ions have been proposed to be central to the catalytic mechanisms of RNase H nucleases, bacterial transposases, Holliday junction resolvases, retroviral integrases and many other enzymes. Here we present a sensitive assay for DNA transesterification in which catalysis by human immunodeficiency virus-type 1 (HIV-1) integrase (IN) connects two DNA strands (disintegration reaction), allowing detection using quantitative PCR (qPCR). We present evidence suggesting that the three acidic residues of the IN active site function through metal binding using metal rescue. In this method, the catalytic acidic residues were each substituted with cysteines. Mn2+ binds tightly to the sulfur atoms of the cysteine residues, but Mg2+ does not. We found that Mn2+, but not Mg2+, could rescue catalysis of each cysteine-substituted enzyme, providing evidence for functionally important metal binding by all three residues. We also used the PCR-boosted assay to show that HIV-1 IN could carry out transesterification reactions involving DNA 5′ hydroxyl groups as well as 3′ hydroxyls as nucleophiles. Lastly, we show that Mn2+ by itself (i.e. without enzyme) can catalyze formation of a low level of PCR-amplifiable product under extreme conditions, allowing us to estimate the rate enhancement due to the IN-protein scaffold as at least 60 million-fold. PMID:17085478

Metaloxide--ZrO2 catalysts for the esterification and transesterification of free fatty acids and triglycerides to obtain bio-diesel

DOEpatents

Kim, Manhoe; Salley, Steven O.; Ng, K. Y. Simon

2016-09-06

Mixed metal oxide catalysts (ZnO, CeO, La2O3, NiO, Al203, SiO2, TiO2, Nd2O3, Yb2O3, or any combination of these) supported on zirconia (ZrO2) or hydrous zirconia are provided. These mixed metal oxide catalysts can be prepared via coprecipitation, impregnation, or sol-gel methods from metal salt precursors with/without a Zirconium salt precursor. Metal oxides/ZrO2 catalyzes both esterification and transesterification of oil containing free fatty acids in one batch or in single stage. In particular, these mixed metal oxides supported or added on zirconium oxide exhibit good activity and selectivity for esterification and transesterification. The low acid strength of this catalyst can avoid undesirable side reaction such as alcohol dehydration or cracking of fatty acids. Metal oxides/ZrO2 catalysts are not sensitive to any water generated from esterification. Thus, esterification does not require a water free condition or the presence of excess methanol to occur when using the mixed metal oxide catalyst. The FAME yield obtained with metal oxides/ZrO2 is higher than that obtained with homogeneous sulfuric acid catalyst. Metal oxides/ZrO2 catalasts can be prepared as strong pellets and in various shapes for use directly in a flow reactor. Furthermore, the pellet has a strong resistance toward dissolution to aqueous or oil phases.

Biodiesel Production from Chlorella protothecoides Oil by Microwave-Assisted Transesterification

PubMed Central

Gülyurt, Mustafa Ömer; Özçimen, Didem; İnan, Benan

2016-01-01

In this study, biodiesel production from microalgal oil by microwave-assisted transesterification was carried out to investigate its efficiency. Transesterification reactions were performed by using Chlorella protothecoides oil as feedstock, methanol, and potassium hydroxide as the catalyst. Methanol:oil ratio, reaction time and catalyst:oil ratio were investigated as process parameters affected methyl ester yield. 9:1 methanol/oil molar ratio, 1.5% KOH catalyst/oil ratio and 10 min were optimum values for the highest fatty acid methyl ester yield. PMID:27110772

Biodiesel Production from Chlorella protothecoides Oil by Microwave-Assisted Transesterification.

PubMed

Gülyurt, Mustafa Ömer; Özçimen, Didem; İnan, Benan

2016-04-22

In this study, biodiesel production from microalgal oil by microwave-assisted transesterification was carried out to investigate its efficiency. Transesterification reactions were performed by using Chlorella protothecoides oil as feedstock, methanol, and potassium hydroxide as the catalyst. Methanol:oil ratio, reaction time and catalyst:oil ratio were investigated as process parameters affected methyl ester yield. 9:1 methanol/oil molar ratio, 1.5% KOH catalyst/oil ratio and 10 min were optimum values for the highest fatty acid methyl ester yield.

Alkaline in situ transesterification of Aurantiochytrium sp. KRS 101 using potassium carbonate.

PubMed

Sung, Mina; Han, Jong-In

2016-04-01

The aims of this work were to evaluate K2CO3 as a potent alkaline catalyst for in situ transesterification of Aurantiochytrium sp. KRS 101, one step process in which oil extraction and conversion take place together. This K2CO3-based in situ transesterification was optimized in terms of recovery yield of fatty acid methyl esters (FAMEs) by way of varying biomass concentration, reaction temperature, reaction time, and catalyst concentration. The optimal condition was achieved at 50g/L of biomass concentration and 1% of K2CO3 in the methanol, 25°C of reaction temperature, and 5min of reaction time, resulting in the FAME recovery yield over 90%. It was found that K2CO3 performed better than any other tested catalysts including acids, supporting the notion that K2CO3 is a promising catalyst, especially for in situ transesterification. Copyright © 2016. Published by Elsevier Ltd.

Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

NASA Astrophysics Data System (ADS)

Purceno, Aluir D.; Machado, Bruno F.; Teixeira, Ana Paula C.; Medeiros, Tayline V.; Benyounes, Anas; Beausoleil, Julien; Menezes, Helvecio C.; Cardeal, Zenilda L.; Lago, Rochel M.; Serp, Philippe

2014-11-01

In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and a metal-catalyzed aqueous oxidation of heptanol with molecular oxygen.In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and a metal-catalyzed aqueous oxidation of heptanol with molecular oxygen. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr04005h

Influence of vegetable oils fatty acid composition on reaction temperature and glycerides conversion to biodiesel during transesterification.

PubMed

Pinzi, S; Gandía, L M; Arzamendi, G; Ruiz, J J; Dorado, M P

2011-01-01

Presence of unreacted glycerides in biodiesel may reduce drastically its quality. This is why conversion of raw material in biodiesel through transesterification needs to readjust reaction parameter values to complete. In the present work, monitoring of glycerides transformation in biodiesel during the transesterification of vegetable oils was carried out. To check the influence of the chemical composition on glycerides conversion, selected vegetable oils covered a wide range of fatty acid composition. Reactions were carried out under alkali-transesterification in the presence of methanol. In addition, a multiple regression model was proposed. Results showed that kinetics depends on chemical and physical properties of the oils. It was found that the optimal reaction temperature depends on both length and unsaturation degree of vegetable oils fatty acid chains. Vegetable oils with higher degree of unsaturation exhibit faster monoglycerides conversion to biodiesel. It can be concluded that fatty acid composition influences reaction parameters and glycerides conversion, hence biodiesel yield and economic viability. Copyright © 2010 Elsevier Ltd. All rights reserved.

Pentynyl dextran as a support matrix for immobilization of serine protease subtilisin Carlsberg and its use for transesterification of N-acetyl-L-phenylalanine ethyl ester in organic media.

PubMed

Tahir, Muhammad Nazir; Cho, Eunae; Mischnick, Petra; Lee, Jae Yung; Yu, Jae-Hyuk; Jung, Seunho

2014-04-01

In this study, serine protease (subtilisin Carlsberg) was immobilized on pentynyl dextran (PyD, O-alkynyl ether of dextran, 1) and used for the transesterification of N-acetyl-L-phenylalanine ethyl ester (2) with different aliphatic (1-propanol, 1-butanol, 1-pentanol, 1-hexanol) and aromatic (benzyl alcohol, 2-phenyl ethanol, 4-phenyl-1-butanol) alcohols in tetrahydrofuran (THF). The effect of carbon chain length in aliphatic and aromatic alcohols on initial and average transesterification rate, transesterification activity of immobilized enzyme and yield of the reaction under selected reaction conditions was investigated. The transesterification reactivity of the enzyme and yield of the reaction increased as the chain length of the alcohols decreased. Furthermore, almost no change in yield was observed when the immobilized enzyme was repeatedly used for selected alcohols over six cycles. Intrinsic fluorescence analysis showed that the catalytic activity of the immobilized enzyme in THF was maintained due to retention of the tertiary structure of the enzyme after immobilization on PyD (1).

Atomistic Model for the Polyamide Formation from β-Lactam Catalyzed by Candida Antarctica Lipase B

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baum, Iris; Elsasser, Brigitta M.; Schwab, Leendert

2011-04-01

Candida antarctica lipase B (CALB) is an established biocatalyst for a variety of transesterification, amidation, and polymerization reactions. In contrast to polyesters, polyamides are not yet generally accessible via enzymatic polymerization. In this regard, an enzyme-catalyzed ring-opening polymerization of {beta}-lactam (2-azetidinone) using CALB is the first example of an enzymatic polyamide formation yielding unbranched poly({beta}-alanine), nylon 3. The performance of this polymerization, however, is poor, considering the maximum chain length of 18 monomer units with an average length of 8, and the molecular basis of the reaction so far is not understood. We have employed molecular modeling techniques using dockingmore » tools, molecular dynamics, and QM/MM procedures to gain insight into the mechanistic details of the various reaction steps involved. As a result, we propose a catalytic cycle for the oligomerization of {beta}-lactam that rationalizes the activation of the monomer, the chain elongation by additional {beta}-lactam molecules, and the termination of the polymer chain. In addition, the processes leading to a premature chain termination are studied. Particularly, the QM/MM calculation enables an atomistic description of all eight steps involved in the catalytic cycle, which features an in situ-generated {beta}-alanine as the elongating monomer and which is compatible with the experimental findings.« less

Establishing a green platform for biodiesel synthesis via strategic utilization of biochar and dimethyl carbonate.

PubMed

Lee, Jechan; Jung, Jong-Min; Oh, Jeong-Ik; Sik Ok, Yong; Kwon, Eilhann E

2017-10-01

To establish a green platform for biodiesel production, this study mainly investigates pseudo-catalytic (non-catalytic) transesterification of olive oil. To this end, biochar from agricultural waste (maize residue) and dimethyl carbonate (DMC) as an acyl acceptor were used for pseudo-catalytic transesterification reaction. Reaction parameters (temperature and molar ratio of DMC to olive oil) were also optimized. The biodiesel yield reached up to 95.4% under the optimal operational conditions (380°C and molar ratio of DMC to olive oil (36:1)). The new sustainable environmentally benign biodiesel production introduced in this study is greener and faster than conventional transesterification reactions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Analysis of parameter and interaction between parameter of the microwave assisted transesterification process of coconut oil using response surface methodology

NASA Astrophysics Data System (ADS)

Hidayanti, Nur; Suryanto, A.; Qadariyah, L.; Prihatini, P.; Mahfud, Mahfud

2015-12-01

A simple batch process was designed for the transesterification of coconut oil to alkyl esters using microwave assisted method. The product with yield above 93.225% of alkyl ester is called the biodiesel fuel. Response surface methodology was used to design the experiment and obtain the maximum possible yield of biodiesel in the microwave-assisted reaction from coconut oil with KOH as the catalyst. The results showed that the time reaction and concentration of KOH catalyst have significant effects on yield of alkyl ester. Based on the response surface methodology using the selected operating conditions, the time of reaction and concentration of KOH catalyst in transesterification process were 150 second and 0.25%w/w, respectively. The largest predicted and experimental yield of alkyl esters (biodiesel) under the optimal conditions are 101.385% and 93.225%, respectively. Our findings confirmed the successful development of process for the transesterification reaction of coconut oil by microwave-assisted heating, which is effective and time-saving for alkyl ester production.

Lipase-catalyzed highly enantioselective kinetic resolution of boron-containing chiral alcohols.

PubMed

Andrade, Leandro H; Barcellos, Thiago

2009-07-16

The first application of enzymes as catalysts to obtain optically pure boron compounds is described. The kinetic resolution of boron-containing chiral alcohols via enantioselective transesterification catalyzed by lipases was studied. Aromatic, allylic, and aliphatic secondary alcohols containing a boronate ester or boronic acid group were resolved by lipase from Candida antartica (CALB), and excellent E values (E > 200) and high enantiomeric excesses (up to >99%) of both remaining substrates and acetylated product were obtained.

A more robust model of the biodiesel reaction, allowing identification of process conditions for significantly enhanced rate and water tolerance.

PubMed

Eze, Valentine C; Phan, Anh N; Harvey, Adam P

2014-03-01

A more robust kinetic model of base-catalysed transesterification than the conventional reaction scheme has been developed. All the relevant reactions in the base-catalysed transesterification of rapeseed oil (RSO) to fatty acid methyl ester (FAME) were investigated experimentally, and validated numerically in a model implemented using MATLAB. It was found that including the saponification of RSO and FAME side reactions and hydroxide-methoxide equilibrium data explained various effects that are not captured by simpler conventional models. Both the experiment and modelling showed that the "biodiesel reaction" can reach the desired level of conversion (>95%) in less than 2min. Given the right set of conditions, the transesterification can reach over 95% conversion, before the saponification losses become significant. This means that the reaction must be performed in a reactor exhibiting good mixing and good control of residence time, and the reaction mixture must be quenched rapidly as it leaves the reactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transesterification catalyzed by Lipozyme TLIM for biodiesel production from low cost feedstock

NASA Astrophysics Data System (ADS)

Halim, Siti Fatimah Abdul; Hassan, Hamizura; Amri, Nurulhuda; Bashah, Nur Alwani Ali

2015-05-01

The development of new strategies to efficiently synthesize biodiesel is of extreme important. This is because biodiesel has been accepted worldwide as an alternative fuel for diesel engines. Biodiesel as alkyl ester derived from vegetable oil has considerable advantages in terms of environmental protection. The diminishing petroleum reserves are the major driving force for researchers to look for better strategies in producing biodiesel. The main hurdle to commercialization of biodiesel is the cost of the raw material. Biodiesel is usually produced from food-grade vegetable oil that is more expensive than diesel fuel. Therefore, biodiesel produced from food-grade vegetable oil is currently not economically feasible. Use of an inexpensive raw material such as waste cooking palm oil and non edible oil sea mango are an attractive option to lower the cost of biodiesel. This study addresses an alternative method for biodiesel production which is to use an enzymatic approach in producing biodiesel fuel from low cost feedstock waste cooking palm oil and unrefined sea mango oil using immobilized lipase Lipozyme TL IM. tert-butanol was used as the reaction medium, which eliminated both negative effects caused by excessive methanol and glycerol as the byproduct. Two variables which is methanol to oil molar ratio and enzyme loading were examine in a batch system. Transesterification of waste cooking palm oil reach 65% FAME yield (methanol to oil molar ratio 6:1 and 10% Novozyme 435 based on oil weight), while transesterification of sea mango oil can reach 90% FAME yield (methanol to oil molar ratio 6:1 and 10% Lipozyme TLIM based on oil weight).

Biodiesel transesterification kinetics monitored by pH measurement.

PubMed

Clark, William M; Medeiros, Nicholas J; Boyd, Donal J; Snell, Jared R

2013-05-01

Quantification of a pH change that was observed over the course of the transesterification reaction that converts vegetable oil to biodiesel may provide a simple method to monitor the reaction. Transesterification of canola oil at 6:1 methanol to oil ratio with 0.5 wt.% KOH as catalyst was studied at 25, 35, and 45 °C. Reaction conversion was correlated to pH measurements and the results were shown to be in agreement with an independent measure of conversion using an enzymatic assay for glycerol. Rate constants obtained from these measurements are consistent with those in the literature. The measured pH change appears to be related to dilution of OH(-) ions as the oil is converted to products rather than to depletion of OH(-) due to reaction. Copyright © 2013 Elsevier Ltd. All rights reserved.

Methods and catalysts for making biodiesel from the transesterification and esterification of unrefined oils

DOEpatents

Yan, Shuli [Detroit, MI; Salley, Steven O [Grosse Pointe Park, MI; Ng, K Y. Simon [West Bloomfield, MI

2012-04-24

A method of forming a biodiesel product and a heterogeneous catalyst system used to form said product that has a high tolerance for the presence of water and free fatty acids (FFA) in the oil feedstock is disclosed. This catalyst system may simultaneously catalyze both the esterification of FAA and the transesterification of triglycerides present in the oil feedstock. The catalyst system according to one aspect of the present disclosure represents a class of zinc and lanthanum oxide heterogeneous catalysts that include different ratios of zinc oxide to lanthanum oxides (Zn:La ratio) ranging from about 10:0 to 0:10. The Zn:La ratio in the catalyst is believed to have an effect on the number and reactivity of Lewis acid and base sites, as well as the transesterification of glycerides, the esterification of fatty acids, and the hydrolysis of glycerides and biodiesel.

On the tandem Morita-Baylis-Hillman/transesterification processes. Mechanistic insights for the role of protic solvents

NASA Astrophysics Data System (ADS)

Carpanez, Arthur G.; Coelho, Fernando; Amarante, Giovanni W.

2018-02-01

Despite the remarkable rate acceleration under protic solvents such as alcohols and water, the use of acrylates as activated alkenes places a problem due to the possibility of ester hydrolysis or transesterification. Therefore, the tandem transesterification/Morita-Baylis-Hillman (MBH) reactions were investigated by ESI(+)-MS/(MS) and 1H NMR techniques. For the first time, the MBH back-reaction was fully examined by ESI(+)-MS/(MS) using labelling reagents revealed the complex equilibrium involving the Michael-type addition step of DABCO to acrylate. C- and O-protonation were observed at this stage, showing the transesterification process occurs previous to the aldol step, which is the rate-determining step of the mechanism. At this stage, a short-lived tetrahedral intermediate might be involved and should be considered in these processes.

One step transesterification process of sludge palm oil (SPO) by using deep eutectic solvent (DES) in biodiesel production

NASA Astrophysics Data System (ADS)

Manurung, Renita; Ramadhani, Debbie Aditia; Maisarah, Siti

2017-06-01

Biodiesel production by using sludge palm oil (SPO) as raw material is generally synthesized in two step reactions, namely esterification and transesterification, because the free fatty acid (FFA) content of SPO is relatively high. However, the presence of choline chloride (ChCl), glycerol based deep eutectic solvent (DES), in transesterification may produce biodiesel from SPO in just one step. In this study, DES was produced by the mixture of ChCl and glycerol at molar ratio of 1:2 at a temperature of 80°C and stirring speed of 400 rpm for 1 hour. DES was characterized by its density and viscosity. The transesterification process was performed at reaction temperature of 70 °C, ethanol to oil molar with ratio of 9:1, sodium hydroxide as catalyst concentration of 1 % wt, DES as cosolvent with concentration of 0 to 5 % wt, stirring speed of 400 rpm, and one hour reaction time. The obtained biodiesel was then assessed with density, viscosity, and ester content as the parameters. FFA content of SPO as the raw material was 7.5290 %. In this case, DES as cosolvent in one step transesterification process of low feedstock could reduce the side reaction (saponification), decrease the time reaction, decrease the surface tension between ethanol and oil, and increase the mass transfer that simultaneously simplified the purification process and obtained the highest yield. The esters properties met the international standards of ASTM D 6751, with the highest yield obtained was 83.19% with 99.55% of ester content and the ratio of ethanol:oil of 9:1, concentration of DES of 4%, catalyst amount of 1%, temperature of reaction at 70°C and stirring speed of 400 rpm.

Biodiesel from Citrus reticulata (Mandarin orange) seed oil, a potential non-food feedstock

USDA-ARS?s Scientific Manuscript database

Oil extracted from Citrus reticulata (Mandarin orange) seeds was investigated as a potential feedstock for the production of biodiesel. The biodiesel fuel was prepared by sodium methoxide-catalyzed transesterification of the oil with methanol. Fuel properties that were determined include cetane numb...

HPLC method for rapidly following biodiesel fuel transesterification reaction progress using a core-shell column.

PubMed

Allen, Samuel J; Ott, Lisa S

2012-07-01

There are a wide and growing variety of feedstocks for biodiesel fuel. Most commonly, these feedstocks contain triglycerides which are transesterified into the fatty acid alkyl esters (FAAEs) which comprise biodiesel fuel. While the tranesterification reaction itself is simple, monitoring the reaction progress and reaction products is not. Gas chromatography-mass spectrometry is useful for assessing the FAAE products, but does not directly address either the tri-, di-, or monoglycerides present from incomplete transesterification or the free fatty acids which may also be present. Analysis of the biodiesel reaction mixture is complicated by the solubility and physical property differences among the components of the tranesterification reaction mixture. In this contribution, we present a simple, rapid HPLC method which allows for monitoring all of the main components in a biodiesel fuel transesterification reaction, with specific emphasis on the ability to monitor the reaction as a function of time. The utilization of a relatively new, core-shell stationary phase for the HPLC column allows for efficient separation of peaks with short elution times, saving both time and solvent.

Biodiesel production from waste frying oil using waste animal bone and solar heat.

PubMed

Corro, Grisel; Sánchez, Nallely; Pal, Umapada; Bañuelos, Fortino

2016-01-01

A two-step catalytic process for the production of biodiesel from waste frying oil (WFO) at low cost, utilizing waste animal-bone as catalyst and solar radiation as heat source is reported in this work. In the first step, the free fatty acids (FFA) in WFO were esterified with methanol by a catalytic process using calcined waste animal-bone as catalyst, which remains active even after 10 esterification runs. The trans-esterification step was catalyzed by NaOH through thermal activation process. Produced biodiesel fulfills all the international requirements for its utilization as a fuel. A probable reaction mechanism for the esterification process is proposed considering the presence of hydroxyapatite at the surface of calcined animal bones. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Effect of Acetone Amount Ratio as Co-Solvent to Methanol in Transesterification Reaction of Waste Cooking Oil

NASA Astrophysics Data System (ADS)

Julianto, T. S.; Nurlestari, R.

2018-04-01

The production of biodiesel from waste cooking oil by transesterification reaction using acetone as co-solvent has been carried out. This research studied the optimal amount ratio of acetone as co-solvent to methanol in the transesterification process using homogeneous alkaline catalyst KOH 1% (w/w) of waste cooking oil at room temperature for 15 minutes of reaction time. Mole ratio of waste cooking oil to methanol is 1:12. Acetone was added as co-solvent in varied amount ratio to methanol are 1:4, 1:2, and 1:1, respectively. The results of fatty acid methyl esters (FAME) were analysed using GC-MS instrument. The results showed that the optimal ratio is 1:4 with 99.93% of FAME yield.

Lipase-Catalyzed Synthesis of Sugar Esters in Honey and Agave Syrup.

PubMed

Siebenhaller, Sascha; Gentes, Julian; Infantes, Alba; Muhle-Goll, Claudia; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Ochsenreither, Katrin; Syldatk, Christoph

2018-01-01

Honey and agave syrup are high quality natural products and consist of more than 80% sugars. They are used as sweeteners, and are ingredients of cosmetics or medical ointments. Furthermore, both have low water content, are often liquid at room temperature and resemble some known sugar-based deep eutectic solvents (DES). Since it has been shown that it is possible to synthesize sugar esters in these DESs, in the current work honey or, as vegan alternative, agave syrup are used simultaneously as solvent and substrate for the enzymatic sugar ester production. For this purpose, important characteristics of the herein used honey and agave syrup were determined and compared with other available types. Subsequently, an enzymatic transesterification of four fatty acid vinyl esters was accomplished in ordinary honey and agave syrup. Notwithstanding of the high water content for transesterification reactions of the solvent, the successful sugar ester formation was proved by thin-layer chromatography (TLC) and compared to a sugar ester which was synthesized in a conventional DES. For a clear verification of the sugar esters, mass determinations by ESI-Q-ToF experiments and a NMR analysis were done. These environmentally friendly produced sugar esters have the potential to be used in cosmetics or pharmaceuticals, or to enhance their effectiveness.

Lipase-Catalyzed Synthesis of Sugar Esters in Honey and Agave Syrup

PubMed Central

Siebenhaller, Sascha; Gentes, Julian; Infantes, Alba; Muhle-Goll, Claudia; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Ochsenreither, Katrin; Syldatk, Christoph

2018-01-01

Honey and agave syrup are high quality natural products and consist of more than 80% sugars. They are used as sweeteners, and are ingredients of cosmetics or medical ointments. Furthermore, both have low water content, are often liquid at room temperature and resemble some known sugar-based deep eutectic solvents (DES). Since it has been shown that it is possible to synthesize sugar esters in these DESs, in the current work honey or, as vegan alternative, agave syrup are used simultaneously as solvent and substrate for the enzymatic sugar ester production. For this purpose, important characteristics of the herein used honey and agave syrup were determined and compared with other available types. Subsequently, an enzymatic transesterification of four fatty acid vinyl esters was accomplished in ordinary honey and agave syrup. Notwithstanding of the high water content for transesterification reactions of the solvent, the successful sugar ester formation was proved by thin-layer chromatography (TLC) and compared to a sugar ester which was synthesized in a conventional DES. For a clear verification of the sugar esters, mass determinations by ESI-Q-ToF experiments and a NMR analysis were done. These environmentally friendly produced sugar esters have the potential to be used in cosmetics or pharmaceuticals, or to enhance their effectiveness. PMID:29487847

Lipase-Catalyzed Synthesis of Sugar Esters in Honey and Agave Syrup

NASA Astrophysics Data System (ADS)

Siebenhaller, Sascha; Gentes, Julian; Infantes, Alba; Muhle-Goll, Claudia; Kirschhöfer, Frank; Brenner-Weiß, Gerald; Ochsenreither, Katrin; Syldatk, Christoph

2018-02-01

Honey and agave syrup are high quality natural products and consist of more than 80% sugars. They are used as sweeteners, and are ingredients of cosmetics or medical ointments. Furthermore, both have low water content, are often liquid at room temperature and resemble some known sugar-based deep eutectic solvents. Since it has been shown that it is possible to synthesize sugar esters in these deep eutectic solvents, in the current work honey or, as vegan alternative, agave syrup are used simultaneously as solvent and substrate for the enzymatic sugar ester production. For this purpose, important characteristics of the herein used honey and agave syrup were determined and compared with other available types. Subsequently, an enzymatic transesterification of four fatty acid vinyl esters was accomplished in ordinary honey and agave syrup. Notwithstanding of the high water content for transesterification reactions of the solvent, the successful sugar ester formation was proved by thin-layer chromatography and compared to a sugar ester which was synthesized in a conventional deep eutectic solvent. For a clear verification of the sugar esters, mass determinations by ESI-Q-ToF experiments and a NMR analysis were done. These environmentally friendly produced sugar esters have the potential to be used in cosmetics or pharmaceuticals, or to enhance their effectiveness.

Ultrasound assisted production of fatty acid methyl esters from transesterification of triglycerides with methanol in the presence of KOH catalyst: optimization, mechanism and kinetics.

PubMed

Thanh, Le Tu; Okitsu, Kenji; Maeda, Yasuaki; Bandow, Hiroshi

2014-03-01

Ultrasound assisted transesterification of triglycerides (TG) with methanol in the presence of KOH catalyst was investigated, where the changes in the reactants and products (diglycerides (DG), monoglycerides (MG), fatty acid methyl esters (FAME) and glycerin (GL)) concentrations were discussed to understand the reaction mechanism and kinetics under ultrasound irradiation. The optimum reaction condition for the FAME production was the concentration of KOH 1.0 wt.%, molar ratio of TG to methanol of 1:6, and irradiation time of 25 min. The rate constants during the TG transesterification with methanol into GL and FAME were estimated by a curve fitting method with simulated curves to the obtained experimental results. The rate constants of [Formula: see text] were estimated to be 0.21, 0.008, 0.23, 0.005, 0.14 and 0.001 L mol(-1)min(-1), respectively. The rate determining step for the TG transesterification with methanol into GL and FAME was the reaction of MG with methanol into GL and FAME. Copyright © 2013 Elsevier B.V. All rights reserved.

Lipase catalyzed epoxidation of fatty acid methyl esters derived from unsaturated vegetable oils in absence of carboxylic acid.

PubMed

Sustaita-Rodríguez, Alejandro; Ramos-Sánchez, Víctor H; Camacho-Dávila, Alejandro A; Zaragoza-Galán, Gerardo; Espinoza-Hicks, José C; Chávez-Flores, David

2018-04-11

Nowadays the industrial chemistry reactions rely on green technologies. Enzymes as lipases are increasing its use in diverse chemical processes. Epoxidized fatty acid methyl esters obtained from transesterification of vegetable oils have recently found applications as polymer plasticizer, agrochemical, cosmetics, pharmaceuticals and food additives. In this research article, grapeseed, avocado and olive oils naturally containing high percents of mono and poly unsaturations were used as starting materials for the production of unsaturated fatty acid methyl esters. The effect of lauric acid as an active oxygen carrier was studied on epoxidation reactions where unsaturated fatty acid methyl esters were converted to epoxy fatty acid methyl esters using immobilized Candida antarctica Lipase type B as catalyst and hydrogen peroxide as oxygen donor at mild temperature and pressure conditions. After this study it was confirmed by 1 H NMR, 13 C NMR and GC-MS that the addition of lauric acid to the enzymatic reaction is unnecessary to transform the alkenes in to epoxides. It was found that quantitative conversions were possible in despite of a carboxylic acid absence.

Rapid alkali catalyzed transesterification of microalgae lipids to biodiesel using simultaneous cooling and microwave heating and its optimization.

PubMed

Chee Loong, Teo; Idris, Ani

2014-12-01

Biodiesel with improved yield was produced from microalgae biomass under simultaneous cooling and microwave heating (SCMH). Nannochloropsis sp. and Tetraselmis sp. which were known to contain higher lipid species were used. The yield obtained using this novel technique was compared with the conventional heating (CH) and microwave heating (MWH) as the control method. The results revealed that the yields obtained using the novel SCMH were higher; Nannochloropsis sp. (83.33%) and Tetraselmis sp. (77.14%) than the control methods. Maximum yields were obtained using SCMH when the microwave was set at 50°C, 800W, 16h of reaction with simultaneous cooling at 15°C; and water content and lipid to methanol ratio in reaction mixture was kept to 0 and 1:12 respectively. GC analysis depicted that the biodiesel produced from this technique has lower carbon components (<19 C) and has both reasonable CN and IV reflecting good ignition and lubricating properties. Copyright © 2014 Elsevier Ltd. All rights reserved.

Optimization of the isolation and quantitation of kahweol and cafestol in green coffee oil.

PubMed

Chartier, Agnes; Beaumesnil, Mathieu; de Oliveira, Alessandra Lopes; Elfakir, Claire; Bostyn, Stephane

2013-12-15

Kahweol and cafestol are two diterpenes that exist mainly as esters of fatty acids in green coffee oil. To recover them under their free form they have to be either saponified or trans-esterified. These two compounds are well known to be sensitive to heat, and reagents, therefore experimental conditions used in the transesterification reaction are critical. In this paper, a Doehlert experimental design plan is used to optimize the transesterification conditions using some key variables such as the temperature of the reaction, the reagent base concentration and the duration of the reaction. Therefore, the optimal parameters determined from the Doehlert design are equal to 70 °C, temperature of the reaction; 1.25 mol L(-1) concentration of the reagent base; and 60 min reaction time. The contour plots show that the extracted quantity of kahweol and cafestol can depend greatly from the experimental conditions. After transesterification, the free form of the diterpernes is extracted from the lipid fraction using liquid-liquid extraction and analyzed using GC-FID without prior derivatization. The amount of kahweol and cafestol obtained from green coffee oil obtained by cold mechanical press of Catuai coffee bean is equal to 33.2±2.2 and 24.3±2.4 g kg(-1)oil, respectively. In an attempt to streamline the process, the transesterification reaction is performed in an in-flow chemistry reactor using the optimal conditions obtained with the Doehlert experimental design. The amount of kahweol and cafestol obtained from the same green coffee oil is equal to 43.5 and 30.072 g kg(-1)oil, respectively. Results are slightly higher compared to the ones obtained with the batch procedure. This can be explained by a better mixing of the coffee oil with the reagents and a faster transesterification reaction. © 2013 Elsevier B.V. All rights reserved.

Solvent-Free Lipase-Catalyzed Synthesis of Diacylgycerols as Low-Calorie Food Ingredients.

PubMed

Vázquez, Luis; González, Noemí; Reglero, Guillermo; Torres, Carlos

2016-01-01

Problems derived from obesity and overweight have recently promoted the development of fat substitutes and other low-calorie foods. On the one hand, fats with short- and medium-chain fatty acids are a source of quick energy, easily hydrolyzable and hardly stored as fat. Furthermore, 1,3-diacylglycerols are not hydrolyzed to 2-monoacylglycerols in the gastrointestinal tract, reducing the formation of chylomicron and lowers the serum level of triacylglycerols by decreasing its resynthesis in the enterocyte. In this work, these two effects were combined to synthesize short- and medium-chain 1,3-diacylglycerols, leading to a product with great potential as for their low-calorie properties. Lipase-catalyzed transesterification reactions were performed between short- and medium-chain fatty acid ethyl esters and glycerol. Different variables were investigated, such as the type of biocatalyst, the molar ratio FAEE:glycerol, the adsorption of glycerol on silica gel, or the addition of lecithin. Best reaction conditions were evaluated considering the percentage of 1,3-DAG produced and the reaction rate. Except Novozym 435 (Candida antarctica), other lipases required the adsorption of glycerol on silica gel to form acylglycerols. Lipases that gave the best results with adsorption were Novozym 435 and Lipozyme RM IM (Rhizomucor miehei) with 52 and 60.7% DAG at 32 h, respectively. Because of its specificity for sn-1 and sn-3 positions, lipases leading to a higher proportion of 1,3-DAG vs. 1,2-DAG were Lipozyme RM IM (39.8 and 20.9%, respectively) and Lipase PLG (Alcaligenes sp.) (35.9 and 19.3%, respectively). By adding 1% (w/w) of lecithin to the reaction with Novozym 435 and raw glycerol, the reaction rate was considerably increased from 41.7 to 52.8% DAG at 24 h.

Solvent-Free Lipase-Catalyzed Synthesis of Diacylgycerols as Low-Calorie Food Ingredients

PubMed Central

Vázquez, Luis; González, Noemí; Reglero, Guillermo; Torres, Carlos

2016-01-01

Problems derived from obesity and overweight have recently promoted the development of fat substitutes and other low-calorie foods. On the one hand, fats with short- and medium-chain fatty acids are a source of quick energy, easily hydrolyzable and hardly stored as fat. Furthermore, 1,3-diacylglycerols are not hydrolyzed to 2-monoacylglycerols in the gastrointestinal tract, reducing the formation of chylomicron and lowers the serum level of triacylglycerols by decreasing its resynthesis in the enterocyte. In this work, these two effects were combined to synthesize short- and medium-chain 1,3-diacylglycerols, leading to a product with great potential as for their low-calorie properties. Lipase-catalyzed transesterification reactions were performed between short- and medium-chain fatty acid ethyl esters and glycerol. Different variables were investigated, such as the type of biocatalyst, the molar ratio FAEE:glycerol, the adsorption of glycerol on silica gel, or the addition of lecithin. Best reaction conditions were evaluated considering the percentage of 1,3-DAG produced and the reaction rate. Except Novozym 435 (Candida antarctica), other lipases required the adsorption of glycerol on silica gel to form acylglycerols. Lipases that gave the best results with adsorption were Novozym 435 and Lipozyme RM IM (Rhizomucor miehei) with 52 and 60.7% DAG at 32 h, respectively. Because of its specificity for sn-1 and sn-3 positions, lipases leading to a higher proportion of 1,3-DAG vs. 1,2-DAG were Lipozyme RM IM (39.8 and 20.9%, respectively) and Lipase PLG (Alcaligenes sp.) (35.9 and 19.3%, respectively). By adding 1% (w/w) of lecithin to the reaction with Novozym 435 and raw glycerol, the reaction rate was considerably increased from 41.7 to 52.8% DAG at 24 h. PMID:26904539

Effects of methanol-to-oil ratio, catalyst amount and reaction time on the FAME yield by in situ transesterification of rubber seeds (Hevea brasiliensis)

NASA Astrophysics Data System (ADS)

Abdulkadir, Bashir Abubakar; Uemura, Yoshimitsu; Ramli, Anita; Osman, Noridah B.; Kusakabe, Katsuki; Kai, Takami

2014-10-01

In this research, biodiesel is produced by in situ transesterification (direct transesterification) method from the rubber seeds using KOH as a catalyst. The influence of methanol to seeds mass ratio, duration of reaction, and catalyst loading was investigated. The result shows that, the best ratio of seeds to methanol is 1:6 (10 g seeds with 60 g methanol), 120 minutes reaction time and catalyst loading of 3.0 g. The maximum FAME yield obtain was 70 %. This findings support FAME production from the seeds of rubber tree using direct transesterifcation method from the seeds of rubber tree as an alternative to diesel fuel. Also, significant properties of biodiesel such as cloud point, density, pour point, specific gravity, and viscosity were investigated.

Biodiesel production via the transesterification of soybean oil using waste starfish (Asterina pectinifera).

PubMed

Jo, Yong Beom; Park, Sung Hoon; Jeon, Jong-Ki; Ko, Chang Hyun; Ryu, Changkook; Park, Young-Kwon

2013-07-01

Calcined waste starfish was used as a base catalyst for the production of biodiesel from soybean oil for the first time. A batch reactor was used for the transesterification reaction. The thermal characteristics and crystal structures of the waste starfish were investigated by thermo-gravimetric analysis and X-ray diffraction. The biodiesel yield was determined by measuring the content of fatty acid methyl esters (FAME). The calcination temperature appeared to be a very important parameter affecting the catalytic activity. The starfish-derived catalyst calcined at 750 °C or higher exhibited high activity for the transesterification reaction. The FAME content increased with increasing catalyst dose and methanol-over-oil ratio.

The ligand effect on the hydrolytic reactivity of Zn(II) complexes toward phosphate diesters.

PubMed

Bonfá, Lodovico; Gatos, Maddalena; Mancin, Fabrizio; Tecilla, Paolo; Tonellato, Umberto

2003-06-16

The catalytic effects of the Zn(II) complexes of a series of poliaminic ligands in the hydrolysis of the activated phosphodiesters bis-p-nitrophenyl phosphate (BNP) and 2-hydroxypropyl-p-nitrophenyl phosphate (HPNP) have been investigated. The reactions show first-order rate dependency on both substrate and metal ion complex and a pH dependence which is diagnostic of the acid dissociation of the reactive species. The mechanism of the metal catalyzed transesterification of HPNP has been assessed by solvent isotopic kinetic effect studies and involves the intramolecular nucleophilic attack of the substrate alcoholic group, activated by metal ion coordination. The intrinsic reactivity of the different complexes is controlled by the nature and structure of the ligand: complexes of tridentate ligands, particularly if characterized by a facial coordination mode, are more reactive than those of tetradentate ligands which can hardly allow binding sites for the substrate. In the case of tridentate ligands that form complexes with a facial coordination mode, a linear Brønsted correlation between the reaction rate (log k) and the pK(a) of the active nucleophile is obtained. The beta(nuc) values are 0.75 for the HPNP transesterification and 0.20 for the BNP hydrolysis. These values are indicated as the result of the combination of two opposite Lewis acid effects of the Zn(II) ion: the activation of the substrate and the efficiency of the metal coordinated nucleophile. The latter factor apparently prevails in determining the intrinsic reactivity of the Zn(II) complexes.

Transesterification of coconut oil for FAME production using ultrasound

NASA Astrophysics Data System (ADS)

Supriadi, Eko; Marlinda, Lenny; Prajitno, Danawati Hari; Mahfud, Mahfud

2017-05-01

To overcome energy crisis, the vegetable oils-derived biofuel can be chosen as an alternative to petroleum-based diesel. The transesterification of coconut oil in methanol with K/γ-Al2O3 catalyst using ultrasound-assisted to produce fatty acid methyl ester (FAME) as one of type biofuel was studied. The reaction occurred in batch reactor at a 9 : 1 molar ratio of methanol to coconut oil. The following reaction conditions were used in the catalytic test : concentration of catalyst to oil of 0.5, 1.0, 1.5, 2.0, and 2.5%, the reaction time of 10, 20, 30, 60, 90, 120, and 150 s, and the frequency ultrasonication of 20 and 40 KHz. At first, the preparation of K/γ-Al2O3 catalyst was done and followed by transesterification process. After reaction, the phase separation and purification from impurities were done. Finally, FAME was analized based on this parameters, i.e., yield, density, viscosity, and flash point. FAME yield of 93.76% was obtained at the frequency ultrasonication of 40 kHz with K/γ-Al2O3 catalyst concentration to oil of 2.5 wt.% for 150 s. It's the best conditions for FAME production by transesterification of coconut oil using ultrasound-assisted.

Lipase-catalyzed transesterification to remove saturated monoacylglycerols from biodiesel

USDA-ARS?s Scientific Manuscript database

Saturated monoacylglycerols (SMG) are known to be present in fatty acid methyl esters (FAME) intended to be used as biodiesel. These SMG can strongly affect the properties of biofuels such as the cloud point, and they have been implicated in engine failure due to filter plugging. It is shown here th...

Metal ion-dependent DNAzymes and their applications as biosensors.

PubMed

Lan, Tian; Lu, Yi

2012-01-01

Long considered to serve solely as the genetic information carrier, DNA has been shown in 1994 to be able to act as DNA catalysts capable of catalyzing a trans-esterification reaction similar to the action of ribozymes and protein enzymes. Although not yet found in nature, numerous DNAzymes have been isolated through in vitro selection for catalyzing many different types of reactions in the presence of different metal ions and thus become a new class of metalloenzymes. What remains unclear is how DNA can carry out catalysis with simpler building blocks and fewer functional groups than ribozymes and protein enzymes and how DNA can bind metal ions specifically to perform these functions. In the past two decades, many biochemical and biophysical studies have been carried out on DNAzymes, especially RNA-cleaving DNAzymes. Important insights have been gained regarding their metal-dependent activity, global folding, metal binding sites, and catalytic mechanisms for these DNAzymes. Because of their high metal ion selectivity, one of the most important practical applications for DNAzymes is metal ion detection, resulting in highly sensitive and selective fluorescent, colorimetric, and electrochemical sensors for a wide range of metal ions such as Pb(2+), UO2 2 +,[Formula: see text] including paramagnetic metal ions such as Cu(2+). This chapter summarizes recent progresses in in vitro selection of metal ion-selective DNAzymes, their biochemical and biophysical studies and sensing applications.

Noncatalytic transformation of the crude lipid of ChlorellaI vulgaris into fatty acid methyl ester (FAME) with charcoal via a thermo-chemical process.

PubMed

Kwon, Eilhann E; Jeon, Young Jae; Yi, Haakrho

2013-02-01

The noncatalytic transformation of the crude lipid of Chlorella vulgaris (C. vulgaris) into fatty acid methyl ester (FAME) via a thermo-chemical process was mainly investigated in this work. The crude lipid of C. vulgaris was recovered by means of solvent extraction from C. vulgaris cultivated in a raceway pond. The conventional catalyzed transesterification of crude lipid of C. vulgaris is notably inhibited by the impurities contained in the crude lipid of C. vulgaris. These impurities are inevitably derived from the solvent extraction process for C. vulgaris. However, this work presents the noncatalytic transesterification of microalgal lipid into FAME, which could be an alternative option. For example, the noncatalytic transformation of microalgal lipid into FAME provides evidence that the esterification of free fatty acids (FFAs) and the transesterification of triglycerides can be combined into a single step less susceptible to the impurities and with a high conversion efficiency (∼97%). Copyright © 2012 Elsevier Ltd. All rights reserved.

Production of biodiesel fuel by transesterification of different vegetable oils with methanol using Al₂O₃ modified MgZnO catalyst.

PubMed

Olutoye, M A; Hameed, B H

2013-03-01

An active heterogeneous Al2O3 modified MgZnO (MgZnAlO) catalyst was prepared and the catalytic activity was investigated for the transesterification of different vegetable oils (refined palm oil, waste cooking palm oil, palm kernel oil and coconut oil) with methanol to produce biodiesel. The catalyst was characterized by using X-ray diffraction, Fourier transform infrared spectra, thermo gravimetric and differential thermal analysis to ascertain its versatility. Effects of important reaction parameters such as methanol to oil molar ratio, catalyst dosage, reaction temperature and reaction time on oil conversion were examined. Within the range of studied variability, the suitable transesterification conditions (methanol/oil ratio 16:1, catalyst loading 3.32 wt.%, reaction time 6h, temperature 182°C), the oil conversion of 98% could be achieved with reference to coconut oil in a single stage. The catalyst can be easily recovered and reused for five cycles without significant deactivation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Monitoring biodiesel reactions of soybean oil and sunflower oil using ultrasonic parameters

NASA Astrophysics Data System (ADS)

Figueiredo, M. K. K.; Silva, C. E. R.; Alvarenga, A. V.; Costa-Félix, R. P. B.

2015-01-01

Biodiesel is an innovation that attempts to substitute diesel oil with biomass. The aim of this paper is to show the development of a real-time method to monitor transesterification reactions by using low-power ultrasound and pulse/echo techniques. The results showed that it is possible to identify different events during the transesterification process by using the proposed parameters, showing that the proposed method is a feasible way to monitor the reactions of biodiesel during its fabrication, in real time, and with relatively low- cost equipment.

High performance catalytic distillation using CNTs-based holistic catalyst for production of high quality biodiesel

PubMed Central

Zhang, Dongdong; Wei, Dali; Li, Qi; Ge, Xin; Guo, Xuefeng; Xie, Zaiku; Ding, Weiping

2014-01-01

For production of biodiesel from bio oils by heterogeneous catalysis, high performance catalysts of transesterification and the further utilization of glycerol have been the two points of research. The process seemed easy, however, has never been well established. Here we report a novel design of catalytic distillation using hierachically integrated CNTs-based holistic catalyst to figure out the two points in one process, which shows high performance both for the conversion of bio oils to biodiesel and, unexpectedly, for the conversion of glycerol to more valuable chemicals at the same time. The method, with integration of nano, meso to macro reactor, has overwhelming advantages over common technologies using liquid acids or bases to catalyze the reactions, which suffer from the high cost of separation and unsolved utilization of glycerol. PMID:24503897

High performance catalytic distillation using CNTs-based holistic catalyst for production of high quality biodiesel

NASA Astrophysics Data System (ADS)

Zhang, Dongdong; Wei, Dali; Li, Qi; Ge, Xin; Guo, Xuefeng; Xie, Zaiku; Ding, Weiping

2014-02-01

For production of biodiesel from bio oils by heterogeneous catalysis, high performance catalysts of transesterification and the further utilization of glycerol have been the two points of research. The process seemed easy, however, has never been well established. Here we report a novel design of catalytic distillation using hierachically integrated CNTs-based holistic catalyst to figure out the two points in one process, which shows high performance both for the conversion of bio oils to biodiesel and, unexpectedly, for the conversion of glycerol to more valuable chemicals at the same time. The method, with integration of nano, meso to macro reactor, has overwhelming advantages over common technologies using liquid acids or bases to catalyze the reactions, which suffer from the high cost of separation and unsolved utilization of glycerol.

Optimization of biodiesel production process using recycled vegetable oil

NASA Astrophysics Data System (ADS)

Lugo, Yarely

Petro diesel toxic emissions and its limited resources have created an interest for the development of new energy resources, such as biodiesel. Biodiesel is traditionally produced by a transesterification reaction between vegetable oil and an alcohol in the presence of a catalyst. However, this process is slow and expensive due to the high cost of raw materials. Low costs feedstock oils such as recycled and animal fats are available but they cannot be transesterified with alkaline catalysts due to high content of free fatty acids, which can lead to undesirable reactions such as saponification. In this study, we reduce free fatty acids content by using an acid pre-treatment. We compare sulfuric acid, hydrochloric acid and ptoluenesulfonic acid (PTSA) to pre-treat recycled vegetable oil. PTSA removes water after 60 minutes of treatment at room temperature or within 15 minutes at 50°C. The pretreatment was followed by a transesterification reaction using alkaline catalyst. To minimize costs and accelerate reaction, the pretreatment and transesterification reaction of recycle vegetable oil was conducted at atmospheric pressure in a microwave oven. Biodiesel was characterized using a GC-MS method.

Biodiesel from wet microalgae: extraction with hexane after the microwave-assisted transesterification of lipids.

PubMed

Cheng, Jun; Huang, Rui; Li, Tao; Zhou, Junhu; Cen, Kefa

2014-10-01

A chloroform-free novel process for the efficient production of biodiesel from wet microalgae is proposed. Crude biodiesel is produced through extraction with hexane after microwave-assisted transesterification (EHMT) of lipids in wet microalgae. Effects of different parameters, including reaction temperature, reaction time, methanol dosage, and catalyst dosage, on fatty acids methyl esters (FAMEs) yield are investigated. The yield of FAME extracted into the hexane from the wet microalgae is increased 6-fold after the transesterification of lipids. The yield of FAME obtained through EHMT of lipids in wet microalgae is comparable to that obtained through direct transesterification of dried microalgae biomass with chloroform; however, FAME content in crude biodiesel obtained through EHMT is 86.74%, while that in crude biodiesel obtained through the chloroform-based process is 75.93%. EHMT ensures that polar pigments present in microalgae are not extracted into crude biodiesel, which leads to a 50% reduction in nitrogen content in crude biodiesel. Copyright © 2014 Elsevier Ltd. All rights reserved.

The feasibility study of crude palm oil transesterification at 30 °C operation.

PubMed

Sim, Jia Huey; Kamaruddin, Azlina Harun; Bhatia, Subhash

2010-12-01

The objective of this research is to investigate the potential of transesterification of crude palm oil (CPO) to biodiesel at 30 degrees C. The mass transfer limitations problem crucial at 30 degrees C due to the viscosity of CPO has been addressed. The process parameters that are closely related to mass transfer effects like enzyme loading, agitation speed and reaction time were optimized. An optimum methanol to oil substrate molar ratio at 6.5:1 was observed and maintained throughout the experiments. The optimum operating condition for the transesterification process was found at 6.67 wt% of enzyme loading and at 150 rpm of agitation speed. The corresponding initial reaction and FAME yield obtained at 6 h were 89.29% FAME yield/hr and 85.01%, respectively. The 85% FAME yield obtained at 30 degrees C operation of CPO transesterification shows that the process is potentially feasible for the biodiesel synthesis. 2010 Elsevier Ltd. All rights reserved.

Boosting the value of biodiesel byproduct by the non-catalytic transesterification of dimethyl carbonate via a continuous flow system under ambient pressure.

PubMed

Kwon, Eilhann E; Yi, Haakrho; Jeon, Young Jae

2014-10-01

Transformation of coconut oil into biodiesel by using dimethyl carbonate (DMC) via a non-catalytic transesterification reaction under ambient pressure was investigated in this study. The non-catalytic transformation to biodiesel was achieved by means of a heterogeneous reaction between liquid triglycerides and gas phase DMC. The reaction was enhanced in the presence of porous material due to its intrinsic physical properties such as tortuosity and absorption/adsorption. The numerous pores in the material served as micro reaction chambers and ensured that there was enough contact time between the liquid triglycerides and the gaseous DMC, which enabled the completion of the transesterification. The highest fatty acid methyl esters (FAMEs) yield achieved was 98±0.5% within 1-2min at a temperature of 360-450°C under ambient pressure. The fast reaction rates made it possible to convert the lipid feedstock into biodiesel via a continuous flow system without the application of increased pressure. This suggested that the commonly used supercritical conditions could be avoided, resulting in huge cost benefits for biodiesel production. In addition, the high value of the byproduct from the transesterification of the lipid feedstock with DMC suggested that the production biodiesel using this method could be more economically competitive. Finally, the basic properties of biodiesel derived from the non-catalytic conversion of rapeseed oil with DMC were summarised. Copyright © 2014 Elsevier Ltd. All rights reserved.

Transesterification of palm oil using sodium silicate base catalyst from geothermal sludge

NASA Astrophysics Data System (ADS)

Perdana, I.; Nugrahanti, N.; Sofiyah; Bendiyasa, I. M.

2016-11-01

The use of solid base catalysts in biodiesel synthesis is becoming more preferable because of their superiority over homogeneous catalysts. In the present work, a strong base catalyst of sodium silicate synthesized from silica-rich geothermal sludge was used in a transesterification of palm oil with methanol. The catalyst was calcined at 400°C for three hours with a temperature ramp of 20°C/min. The transesterification was carried out at varying temperature in the range of 50 - 70°C for 60 minutes with a methanol-palm oil molar ratio of 8.8:1. The catalyst-palm oil ratio was varied in the range of 1 - 5% (w/w). In order to investigate kinetics of reaction, at a certain interval of time samples were taken consecutively during the reaction. Experimental results showed that the sodium silicate was very active in the transesterification of palm oil with methanol. Reaction temperature at 60°C was sufficient to reach a conversion level as high as 93% in a relatively short reaction period. Meanwhile, the high conversion was still achievable with the use of 1 % (w/w) catalyst. In addition, a lumped model of reaction kinetics was adequate to approach the experimental data with a calculated activation energy of 15.73 kcal/mole. Results of the present work suggested that sodium silicate synthesized from local resources of geothermal sludge would become potential solid base catalyst in biodiesel synthesis.

Optimization of transesterification of rubber seed oil using heterogeneous catalyst calcium oxide

NASA Astrophysics Data System (ADS)

Inggrid, Maria; Kristanto, Aldi; Santoso, Herry

2015-12-01

Biodiesel is an alternative fuel manufactured with the help of alkali hydroxide catalyst through transesterification reaction of vegetable oil. This study aims to examine methods and the most suitable conditions for transesterification reaction producing biodiesel from crude rubber seed oil by varying process parameters such as the molar ratio of alcohol, CaO amount as the alkaline catalyst, and reaction time. The rubber seed oil has a high level of free fatty acid content, which means the use of homogenous alkaline catalyst gives some technological problems such as soap formation which leaded in difficulty in the separation and purification of the product. Calcium oxide (CaO) is one of the most favorable heterogeneous base catalysts because it's reusable, noncorrosive, and low cost. Pre-treatment was performed by acid esterification with H2SO4 as the catalyst to decrease the content of free fatty acid in the rubber seed oil, in this pretreatment process the 12% FFA of crude oil could be reduced to below 3% FFA. The product after esterification process was then transesterified by alkaline transesterification by varying process parameters to convert triglyceride into biodiesel. The study found that maximum curvature for biodiesel yield occurred at 9:1 molar ratio of alcohol, 5%w catalyst loading, and 3 hours reaction time. Design expert software is used to determine the optimum point from experimental data. The result showed that the optimum yield of methyl ester from transesterification was 73.5 % by mass with 0.69 degree of desirability. The yielded methyl ester was tested for its density, viscosity, acid number, and solubility to meet SNI requirement standards.

Magnetic Cross-Linked Enzyme Aggregates (mCLEAs) of Candida antarctica lipase: an efficient and stable biocatalyst for biodiesel synthesis.

PubMed

Cruz-Izquierdo, Álvaro; Picó, Enrique A; López, Carmen; Serra, Juan L; Llama, María J

2014-01-01

Enzyme-catalyzed production of biodiesel is the object of extensive research due to the global shortage of fossil fuels and increased environmental concerns. Herein we report the preparation and main characteristics of a novel biocatalyst consisting of Cross-Linked Enzyme Aggregates (CLEAs) of Candida antarctica lipase B (CALB) which are covalently bound to magnetic nanoparticles, and tackle its use for the synthesis of biodiesel from non-edible vegetable and waste frying oils. For this purpose, insolubilized CALB was covalently cross-linked to magnetic nanoparticles of magnetite which the surface was functionalized with -NH2 groups. The resulting biocatalyst combines the relevant catalytic properties of CLEAs (as great stability and feasibility for their reutilization) and the magnetic character, and thus the final product (mCLEAs) are superparamagnetic particles of a robust catalyst which is more stable than the free enzyme, easily recoverable from the reaction medium and reusable for new catalytic cycles. We have studied the main properties of this biocatalyst and we have assessed its utility to catalyze transesterification reactions to obtain biodiesel from non-edible vegetable oils including unrefined soybean, jatropha and cameline, as well as waste frying oil. Using 1% mCLEAs (w/w of oil) conversions near 80% were routinely obtained at 30°C after 24 h of reaction, this value rising to 92% after 72 h. Moreover, the magnetic biocatalyst can be easily recovered from the reaction mixture and reused for at least ten consecutive cycles of 24 h without apparent loss of activity. The obtained results suggest that mCLEAs prepared from CALB can become a powerful biocatalyst for application at industrial scale with better performance than those currently available.

Magnetic Cross-Linked Enzyme Aggregates (mCLEAs) of Candida antarctica Lipase: An Efficient and Stable Biocatalyst for Biodiesel Synthesis

PubMed Central

Cruz-Izquierdo, Álvaro; Picó, Enrique A.; López, Carmen; Serra, Juan L.; Llama, María J.

2014-01-01

Enzyme-catalyzed production of biodiesel is the object of extensive research due to the global shortage of fossil fuels and increased environmental concerns. Herein we report the preparation and main characteristics of a novel biocatalyst consisting of Cross-Linked Enzyme Aggregates (CLEAs) of Candida antarctica lipase B (CALB) which are covalently bound to magnetic nanoparticles, and tackle its use for the synthesis of biodiesel from non-edible vegetable and waste frying oils. For this purpose, insolubilized CALB was covalently cross-linked to magnetic nanoparticles of magnetite which the surface was functionalized with –NH2 groups. The resulting biocatalyst combines the relevant catalytic properties of CLEAs (as great stability and feasibility for their reutilization) and the magnetic character, and thus the final product (mCLEAs) are superparamagnetic particles of a robust catalyst which is more stable than the free enzyme, easily recoverable from the reaction medium and reusable for new catalytic cycles. We have studied the main properties of this biocatalyst and we have assessed its utility to catalyze transesterification reactions to obtain biodiesel from non-edible vegetable oils including unrefined soybean, jatropha and cameline, as well as waste frying oil. Using 1% mCLEAs (w/w of oil) conversions near 80% were routinely obtained at 30°C after 24 h of reaction, this value rising to 92% after 72 h. Moreover, the magnetic biocatalyst can be easily recovered from the reaction mixture and reused for at least ten consecutive cycles of 24 h without apparent loss of activity. The obtained results suggest that mCLEAs prepared from CALB can become a powerful biocatalyst for application at industrial scale with better performance than those currently available. PMID:25551445

A Simple, Safe Method for Preparation of Biodiesel

ERIC Educational Resources Information Center

Behnia, Mahin S.; Emerson, David W.; Steinberg, Spencer M.; Alwis, Rasika M.; Duenas, Josue A.; Serafino, Jessica O.

2011-01-01

An experiment suitable for organic chemistry students is described. Biodiesel, a "green" fuel, consists of methyl or ethyl esters of long-chain fatty acids called FAMES (fatty acid methyl esters) or FAEES (fatty acid ethyl esters). A quick way to make FAMES is a base-catalyzed transesterification of oils or fats derived from plants or from animal…

Synthesis and properties of fatty acid starch esters.

PubMed

Winkler, Henning; Vorwerg, Waltraud; Wetzel, Hendrik

2013-10-15

Being completely bio-based, fatty acid starch esters (FASEs) are attractive materials that represent an alternative to crude oil-based plastics. In this study, two synthesis methods were compared in terms of their efficiency, toxicity and, especially, product solubility with starch laurate (C12) as model compound. Laurates (DS>2) were obtained through transesterification of fatty acid vinylesters in DMSO or reaction with fatty acid chlorides in pyridine. The latter lead to higher DS-values in a shorter reaction time. But due to the much better solubility of the products compared to lauroyl chloride esterified ones, vinylester-transesterification was preferred to optimize reaction parameters, where reaction time could be shortened to 2h. FASEs C6-C18 were also successfully prepared via transesterification. To determine the DS of the resulting starch laurates, the efficient ATR-IR method was compared with common methods (elementary analysis, (1)H NMR). Molar masses (Mw) of the highly soluble starch laurates were analyzed using SEC-MALLS (THF). High recovery rates (>80%) attest to the outstanding solubility of products obtained through transesterification, caused by a slight disintegration during synthesis. Particle size distributions (DLS) demonstrated stable dissolutions in CHCl3 of vinyl laurate esterified - contrary to lauroyl chloride esterified starch. For all highly soluble FASEs (C6-C18), formation of concentrated solutions (10 wt%) is feasible. Copyright © 2013 Elsevier Ltd. All rights reserved.

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters

PubMed Central

Urban, Jiri; Svec, Frantisek; Fréchet, Jean M.J.

2011-01-01

An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. PMID:21915852

A monolithic lipase reactor for biodiesel production by transesterification of triacylglycerides into fatty acid methyl esters.

PubMed

Urban, Jiri; Svec, Frantisek; Fréchet, Jean M J

2012-02-01

An enzymatic reactor with lipase immobilized on a monolithic polymer support has been prepared and used to catalyze the transesterification of triacylglycerides into the fatty acid methyl esters commonly used for biodiesel. A design of experiments procedure was used to optimize the monolithic reactor with variables including control of the surface polarity of the monolith via variations in the length of the hydrocarbon chain in alkyl methacrylate monomer, time of grafting of 1-vinyl-4,4-dimethylazlactone used to activate the monolith, and time used for the immobilization of porcine lipase. Optimal conditions involved the use of a poly(stearyl methacrylate-co-ethylene dimethacrylate) monolith, grafted first with vinylazlactone, then treated with lipase for 2 h to carry out the immobilization of the enzyme. Best conditions for the transesterification of glyceryl tributyrate included a temperature of 37°C and a 10 min residence time of the substrate in the bioreactor. The reactor did not lose its activity even after pumping through it a solution of substrate equaling 1,000 reactor volumes. This enzymatic reactor was also used for the transesterification of triacylglycerides from soybean oil to fatty acid methyl esters thus demonstrating the ability of the reactor to produce biodiesel. Copyright © 2011 Wiley Periodicals, Inc.

Data set for extraction and transesterification of bio-oil from Stoechospermum marginatum, a brown marine algae.

PubMed

Venkatesan, Hariram; Godwin, John J; Sivamani, Seralathan

2017-10-01

The article presents the experimental data on the extraction and transesterification of bio-oil derived from Stoechospermum marginatum, a brown macro marine algae. The samples were collected from Mandapam region, Gulf of Mannar, Tamil Nadu, India. The bio-oil was extracted using Soxhlet technique with a lipid extraction efficiency of 24.4%. Single stage transesterification was adopted due to lower free fatty acid content. The yield of biodiesel was optimized by varying the process parameters. The obtained data showed the optimum process parameters as reaction time 90 min, reaction temperature 65 °C, catalyst concentration 0.50 g and 8:1 M ratio. Furthermore, the data pertaining to the physio-chemical properties of the derived algal biodiesel were also presented.

Model study on transesterification of soybean oil to biodiesel with methanol using solid base catalyst.

PubMed

Liu, Xuejun; Piao, Xianglan; Wang, Yujun; Zhu, Shenlin

2010-03-25

Modeling of the transesterification of vegetable oils to biodiesel using a solid base as a catalyst is very important because the mutual solubilities of oil and methanol will increase with the increasing biodiesel yield. The heterogeneous liquid-liquid-solid reaction system would become a liquid-solid system when the biodiesel reaches a certain content. In this work, we adopted a two-film theory and a steady state approximation assumption, then established a heterogeneous liquid-liquid-solid model in the first stage. After the diffusion coefficients on the liquid-liquid interface and the liquid-solid interface were calculated on the basis of the properties of the system, the theoretical value of biodiesel productivity changing with time was obtained. The predicted values were very near the experimental data, which indicated that the proposed models were suitable for the transesterification of soybean oil to biodiesel when solid bases were used as catalysts. Meanwhile, the model indicated that the transesterification reaction was controlled by both mass transfer and reaction. The total resistance will decrease with the increase in biodiesel yield in the liquid-liquid-solid stage. The solid base catalyst exhibited an activation energy range of 9-20 kcal/mol, which was consistent with the reported activation energy range of homogeneous catalysts.

From Classical to High Throughput Screening Methods for Feruloyl Esterases: A Review.

PubMed

Ramírez-Velasco, Lorena; Armendáriz-Ruiz, Mariana; Rodríguez-González, Jorge Alberto; Müller-Santos, Marcelo; Asaff-Torres, Ali; Mateos-Díaz, Juan Carlos

2016-01-01

Feruloyl esterases (FAEs) are a diverse group of hydrolases widely distributed in plants and microorganisms which catalyzes the cleavage and formation of ester bonds between plant cell wall polysaccharides and phenolic acids. FAEs have gained importance in biofuel, medicine and food industries due to their capability of acting on a large range of substrates for cleaving ester bonds and synthesizing highadded value molecules through esterification and transesterification reactions. During the past two decades extensive studies have been carried out on the production, characterization and classification of FAEs, however only a few reports of suitable High Throughput Screening assays for this kind of enzymes have been reported. This review is focused on a concise but complete revision of classical to High Throughput Screening methods for FAEs, highlighting its advantages and disadvantages, and finally suggesting future perspectives for this important research field.

The synthesis of amphipathic prodrugs of 1,2-diol drugs with saccharide conjugates by high regioselective enzymatic protocol.

PubMed

Quan, Jing; Chen, Zhichun; Han, Chengyou; Lin, Xianfu

2007-02-15

A facile, high regioselective enzymatic synthesis approach for the preparation of amphipathic prodrugs with saccharides of mephenesin and chlorphenesin was developed. Firstly, transesterification of two drugs with divinyl dicarboxylates with different carbon chain length was performed under the catalysis of Candida antarctica lipase acrylic resin and Lipozyme in anhydrous acetone at 50 degrees C, respectively. A series of lipophilic derivatives with vinyl groups of mephenesin and chlorphenesin were prepared. The influences of different organic solvents, enzyme sources, reaction time, and the acylation reagents on the synthesis of vinyl esters were investigated. And then, protease-catalyzed high regioselective acylation of D-glucose and D-mannose with vinyl esters of mephenesin and chlorphenesin gave drug-saccharide derivatives in good yields. The studies of lipophilicity and hydrolysis in vitro of prodrugs verified that drug-saccharide derivatives had amphipathic properties, and both lipophilic and amphipathic drug derivatives had obvious controlled release characteristics.

Pyrogenic transformation of Nannochloropsis oceanica into fatty acid methyl esters without oil extraction for estimating total lipid content.

PubMed

Kim, Jieun; Jung, Jong-Min; Lee, Jechan; Kim, Ki-Hyun; Choi, Tae O; Kim, Jae-Kon; Jeon, Young Jae; Kwon, Eilhann E

2016-07-01

This study fundamentally investigated the pseudo-catalytic transesterification of dried Nannochloropsis oceanica into fatty acid methyl esters (FAMEs) without oil extraction, which was achieved in less than 5min via a thermo-chemical pathway. This study presented that the pseudo-catalytic transesterification reaction was achieved in the presence of silica and that its main driving force was identified as temperature: pores in silica provided the numerous reaction space like a micro-reactor, where the heterogeneous reaction was developed. The introduced FAME derivatization showed an extraordinarily high tolerance of impurities (i.e., pyrolytic products and various extractives). This study also explored the thermal cracking of FAMEs derived from N. oceanica: the thermal cracking of saturated FAMEs was invulnerable at temperatures lower than 400°C. Lastly, this study reported that N. oceanica contained 14.4wt.% of dried N. oceanica and that the introduced methylation technique could be applicable to many research fields sharing the transesterification platform. Copyright © 2016 Elsevier Ltd. All rights reserved.

Biodiesel production by transesterification using immobilized lipase.

PubMed

Narwal, Sunil Kumar; Gupta, Reena

2013-04-01

Biodiesel can be produced by transesterification of vegetable or waste oil catalysed by lipases. Biodiesel is an alternative energy source to conventional fuel. It combines environmental friendliness with biodegradability, low toxicity and renewability. Biodiesel transesterification reactions can be broadly classified into two categories: chemical and enzymatic. The production of biodiesel using the enzymatic route eliminates the reactions catalysed under acid or alkali conditions by yielding product of very high purity. The modification of lipases can improve their stability, activity and tolerance to alcohol. The cost of lipases and the relatively slower reaction rate remain the major obstacles for enzymatic production of biodiesel. However, this problem can be solved by immobilizing the enzyme on a suitable matrix or support, which increases the chances of re-usability. The main factors affecting biodiesel production are composition of fatty acids, catalyst, solvents, molar ratio of alcohol and oil, temperature, water content, type of alcohol and reactor configuration. Optimization of these parameters is necessary to reduce the cost of biodiesel production.

Biodiesel synthesis by direct transesterification of microalga Botryococcus braunii with continuous methanol reflux.

PubMed

Hidalgo, Pamela; Ciudad, Gustavo; Schober, Sigurd; Mittelbach, Martin; Navia, Rodrigo

2015-04-01

Direct transesterification of Botryococcus braunii with continuous acyl acceptor reflux was evaluated. This method combines in one step lipid extraction and esterification/transesterification. Fatty acid methyl esters (FAME) synthesis by direct conversion of microalgal biomass was carried out using sulfuric acid as catalyst and methanol as acyl acceptor. In this system, once lipids are extracted, they are contacted with the catalyst and methanol reaching 82%wt of FAME yield. To optimize the reaction conditions, a factorial design using surface response methodology was applied. The effects of catalyst concentration and co-solvent concentration were studied. Hexane was used as co-solvent for increasing lipid extraction performance. The incorporation of hexane in the reaction provoked an increase in FAME yield from 82% (pure methanol) to 95% when a 47%v/v of hexane was incorporated in the reaction. However, the selectivity towards non-saponifiable lipids such as sterols was increased, negatively affecting biodiesel quality. Copyright © 2015 Elsevier Ltd. All rights reserved.

Block and Graft Copolymers of Polyhydroxyalkanoates

NASA Astrophysics Data System (ADS)

Marchessault, Robert H.; Ravenelle, François; Kawada, Jumpei

2004-03-01

Polyhydroxyalkanoates (PHAs) were modified for diblock copolymer and graft polymer by catalyzed transesterification in the melt and by chemical synthesis to extend the side chains of the PHAs, and the polymers were studied by transmission electron microscopy (TEM) X-ray diffraction, thermal analysis and nuclear magnetic resonance (NMR). Catalyzed transesterification in the melt is used to produce diblock copolymers of poly[3-hydroxybutyrate] (PHB) and monomethoxy poly[ethylene glycol] (mPEG) in a one-step process. The resulting diblock copolymers are amphiphilic and self-assemble into sterically stabilized colloidal suspensions of PHB crystalline lamellae. Graft polymer was synthesized in a two-step chemical synthesis from biosynthesized poly[3-hydroxyoctanoate-co-3-hydroxyundecenoate] (PHOU) containing ca. 25 mol chains. 11-mercaptoundecanoic acid reacts with the side chain alkenes of PHOU by the radical addition creating thioether linkage with terminal carboxyl functionalities. The latter groups were subsequently transformed into the amide or ester linkage by tridecylamine or octadecanol, respectively, producing new graft polymers. The polymers have different physical properties than poly[3-hydroxyoctanoate] (PHO) which is the main component of the PHOU, such as non-stickiness and higher thermal stability. The combination of biosynthesis and chemical synthesis produces a hybrid thermoplastic elastomer with partial biodegradability.

Transesterification of Waste Olive Oil by "Candida" Lipase

ERIC Educational Resources Information Center

Shen, Xiangping; Vasudevan, Palligarnai T.

2008-01-01

Biodiesel was produced by transesterification of waste olive oil with methanol and Novozym [R] 435. The effect of the molar ratio of methanol to triolein, mode of methanol addition, reaction temperature, and mixing speed on biodiesel yield was determined. The effect of different acyl acceptors and/or solvents on biodiesel yield was also evaluated.…

Production of biodiesel via the in situ transesterification of grain sorghum bran and DDGS

USDA-ARS?s Scientific Manuscript database

The acylglycerides in sorghum bran and distiller’s dried grains and solubles (DDGS) from sorghum post-fermentation stillage have been converted to fatty acid methyl esters (FAMEs) using an in-situ transesterification (IST) method. The reactions were conducted at 25 deg C or 40 deg C in the presence...

Effect of sub- and supercritical CO2 treatment on the properties of Pseudomonas cepacia lipase.

PubMed

Chen, Dawei; Zhang, Houjin; Xu, Jing; Yan, Yunjun

2013-07-10

In this work, we have investigated the influences of sub- and supercritical CO2 treatment on the properties of Pseudomonas cepacia lipase (PCL), including its esterification and transesterification activities, structural changes and stability. Results demonstrated that exposure time to subcritical CO2 treatment had a negative effect on PCL transesterification activity whereas exposure time to supercritical CO2 treatment had a positive effect. But generally, most compressed treatments significantly enhanced PCL esterification activity. Conformational analysis by FT-IR and fluorescence emission spectra revealed that enhanced activities after supercritical CO2 treatment were correlated with the secondary and tertiary structural changes of PCL. Secondary structure changes also appeared to be responsible for enhancement of PCL activities by subcritical CO2 treatment. Compared to native PCL, treated PCL's esterification activity significantly decreased in hydrophilic organic media, while transesterification activity significantly increased in tert-amyl alcohol and acetone. After supercritical treatment, the thermal stability of PCL significantly decreased in esterification reactions, however, there was no significant difference in transesterification reactions. Copyright © 2013 Elsevier Inc. All rights reserved.

Detergent assisted ultrasonication aided in situ transesterification for biodiesel production from oleaginous yeast wet biomass.

PubMed

Yellapu, Sravan Kumar; Kaur, Rajwinder; Tyagi, Rajeshwar D

2017-01-01

In situ transesterification of oleaginous yeast wet biomass for fatty acid methyl esters (FAMEs) production using acid catalyst, methanol with or without N-Lauroyl sarcosine (N-LS) treatment was performed. The maximum FAMEs yield obtained with or without N-LS treatment in 24h reaction time was 96.1±1.9 and 71±1.4% w/w, respectively. The N-LS treatment of biomass followed by with or without ultrasonication revealed maximum FAMEs yield of 94.3±1.9% and 82.9±1.8% w/w using methanol to lipid molar ratio 360:1 and catalyst concentration 360mM (64μL H 2 SO 4 /g lipid) within 5 and 25min reaction time, respectively. The FAMEs composition obtained in in situ transesterification was similar to that obtained with conventional two step lipid extraction and transesterification process. Biodiesel fuel properties (density, kinematic viscosity, cetane number and total glycerol) were in accordance with international standard (ASTM D6751), which suggests the suitability of biodiesel as a fuel. Copyright © 2016 Elsevier Ltd. All rights reserved.

Optimization of bio-diesel production from soybean and wastes of cooked oil: combining dielectric microwave irradiation and a SrO catalyst.

PubMed

Koberg, Miri; Abu-Much, Riam; Gedanken, Aharon

2011-01-01

This work offers an optimized method in the transesterification of pristine (soybean) oil and cooked oil to bio-diesel, based on microwave dielectric irradiation as a driving force for the transesterification reaction and SrO as a catalyst. This combination has demonstrated excellent catalytic activity and stability. The transesterification was carried out with and without stirring. According to 1H NMR spectroscopy and TLC results, this combination accelerates the reaction (to less than 60 s), maintaining a very high conversion (99%) and high efficiency. The catalytic activity of SrO under atmospheric pressure in the presence of air and under the argon atmosphere is demonstrated. The optimum conversion of cooked oil (99.8%) is achieved under MW irradiation of 1100 W output with magnetic stirring after only 10 s. The optimum method decreases the cost of bio-diesel production and has the potential for industrial application in the transesterification of cooked oil to bio-diesel. Copyright © 2010 Elsevier Ltd. All rights reserved.

Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation

DOE PAGES

Milivojevic, Ana; Corovic, Marija; Carevic, Milica; ...

2017-09-23

Solubility and stability of flavonoid glycosides, valuable natural constituents of cosmetics and pharmaceuticals, could be improved by lipase-catalyzed acylation. Focus of this study was on development of eco-friendly process for the production of flavonoid acetates. By using phloridzin as model compound and triacetin as acetyl donor and solvent, 100% conversion and high productivity (23.32 g l –1 day –1) were accomplished. Complete conversions of two other glycosylated flavonoids, naringin and esculin, in solvent-free system were achieved, as well. Comprehensive kinetic mechanism based on two consecutive mono-substrate reactions was established where first one represents formation of flavonoid monoacetate and within secondmore » reaction diacetate is being produced from monoacetate. Both steps were regarded as reversible Michaelis-Menten reactions without inhibition. Apparent kinetic parameters for two consecutive reactions (V m constants for substrates and products and K m constants for forward and reverse reactions) were estimated for three examined acetyl acceptors and excellent fitting of experimental data (R 2 > 0.97) was achieved. Obtained results showed that derived kinetic model could be applicable for solvent-free esterifications of different flavonoid glycosides. As a result, it was valid for entire transesterification course (72 h of reaction) which, combined with complete conversions and green character of synthesis, represents firm basis for further process development.« less

Highly efficient enzymatic acetylation of flavonoids: Development of solvent-free process and kinetic evaluation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milivojevic, Ana; Corovic, Marija; Carevic, Milica

Solubility and stability of flavonoid glycosides, valuable natural constituents of cosmetics and pharmaceuticals, could be improved by lipase-catalyzed acylation. Focus of this study was on development of eco-friendly process for the production of flavonoid acetates. By using phloridzin as model compound and triacetin as acetyl donor and solvent, 100% conversion and high productivity (23.32 g l –1 day –1) were accomplished. Complete conversions of two other glycosylated flavonoids, naringin and esculin, in solvent-free system were achieved, as well. Comprehensive kinetic mechanism based on two consecutive mono-substrate reactions was established where first one represents formation of flavonoid monoacetate and within secondmore » reaction diacetate is being produced from monoacetate. Both steps were regarded as reversible Michaelis-Menten reactions without inhibition. Apparent kinetic parameters for two consecutive reactions (V m constants for substrates and products and K m constants for forward and reverse reactions) were estimated for three examined acetyl acceptors and excellent fitting of experimental data (R 2 > 0.97) was achieved. Obtained results showed that derived kinetic model could be applicable for solvent-free esterifications of different flavonoid glycosides. As a result, it was valid for entire transesterification course (72 h of reaction) which, combined with complete conversions and green character of synthesis, represents firm basis for further process development.« less

Synthesis of retinyl palmitate catalyzed by Candida sp.99-125 lipase immobilized on fiber-like SBA-15 mesoporous material.

PubMed

Kai, Zhu; Jianqiang, Wang; Yan-hua, Wang; Hui, Liu; Ping-fang, Han; Ping, Wei

2011-09-01

Candida sp.99-125 lipase was suitable for transesterification of fats and oils to produce fatty acid methyl ester. The adsorption of Candida sp.99-125 lipase onto the fiber-like SBA-15 mesoporous material has been studied. The unaltered structural order of the fiber-like SBA-15 before and after the adsorption has been confirmed by FT-IR, SEM and N2 adsorption. The amount of adsorbed Candida sp.99-125 lipase depends both on the solution pH and reaction time. Good adsorption capacity of Candida sp.99-125 lipase on fiber-like SBA-15 may be due to solution pH from 5.0 to 9.0 especially at 7.0 (93.99 mg enzyme per gram silica is obtained and the activity recovery is 281.05%). A high lipase loading (135.9 mg enzyme per gram silica) was obtained, but it did not produce a proportionate level of catalytic activity. The immobilized Candida sp.99-125 lipase showed increased adaptability in the hydrolysis of p-nitrophenyl acetate compared to free Candida sp.99-125 lipase at pH 5.0-9.0. Meanwhile, the immobilized Candida sp.99-125 lipase showed higher thermal stability than that of free Candida sp.99-125 lipase. And the synthesis of retinyl palmitate in organic solvent with the immobilized Candida sp.99-125 lipase was investigated. The influence factors, such as: the solvent used, the molar ratio and concentrations of substrates, the reaction time and the amount of lipase were studied and optimized. In the conditions of transesterificating 0.164 g retinyl acetate and 0.32 g palmitic acid, 10 mL of solvent hexane, 1:4 of mass ratio of lipase to retinyl acetate, and 6 hours of reaction time, 74.6% of retinyl acetate was converted into retinyl plamitate.

Multiscale methods for computational RNA enzymology

PubMed Central

Panteva, Maria T.; Dissanayake, Thakshila; Chen, Haoyuan; Radak, Brian K.; Kuechler, Erich R.; Giambaşu, George M.; Lee, Tai-Sung; York, Darrin M.

2016-01-01

RNA catalysis is of fundamental importance to biology and yet remains ill-understood due to its complex nature. The multi-dimensional “problem space” of RNA catalysis includes both local and global conformational rearrangements, changes in the ion atmosphere around nucleic acids and metal ion binding, dependence on potentially correlated protonation states of key residues and bond breaking/forming in the chemical steps of the reaction. The goal of this article is to summarize and apply multiscale modeling methods in an effort to target the different parts of the RNA catalysis problem space while also addressing the limitations and pitfalls of these methods. Classical molecular dynamics (MD) simulations, reference interaction site model (RISM) calculations, constant pH molecular dynamics (CpHMD) simulations, Hamiltonian replica exchange molecular dynamics (HREMD) and quantum mechanical/molecular mechanical (QM/MM) simulations will be discussed in the context of the study of RNA backbone cleavage transesterification. This reaction is catalyzed by both RNA and protein enzymes, and here we examine the different mechanistic strategies taken by the hepatitis delta virus ribozyme (HDVr) and RNase A. PMID:25726472

Biodiesel production using waste frying oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Charpe, Trupti W.; Rathod, Virendra K., E-mail: vk.rathod@ictmumbai.edu.in

2011-01-15

Research highlights: {yields} Waste sunflower frying oil is successfully converted to biodiesel using lipase as catalyst. {yields} Various process parameters that affects the conversion of transesterification reaction such as temperature, enzyme concentration, methanol: oil ratio and solvent are optimized. {yields} Inhibitory effect of methanol on lipase is reduced by adding methanol in three stages. {yields} Polar solvents like n-hexane and n-heptane increases the conversion of tranesterification reaction. - Abstract: Waste sunflower frying oil is used in biodiesel production by transesterification using an enzyme as a catalyst in a batch reactor. Various microbial lipases have been used in transesterification reaction tomore » select an optimum lipase. The effects of various parameters such as temperature, methanol:oil ratio, enzyme concentration and solvent on the conversion of methyl ester have been studied. The Pseudomonas fluorescens enzyme yielded the highest conversion. Using the P. fluorescens enzyme, the optimum conditions included a temperature of 45 deg. C, an enzyme concentration of 5% and a methanol:oil molar ratio 3:1. To avoid an inhibitory effect, the addition of methanol was performed in three stages. The conversion obtained after 24 h of reaction increased from 55.8% to 63.84% because of the stage-wise addition of methanol. The addition of a non-polar solvent result in a higher conversion compared to polar solvents. Transesterification of waste sunflower frying oil under the optimum conditions and single-stage methanol addition was compared to the refined sunflower oil.« less

A "Warm Formamide" Scenario for the Origins of Life Might not be so Hot: Comment on "Formamide and the Origin of Life"

NASA Technical Reports Server (NTRS)

Burton, Aaron S.

2012-01-01

In this review, Saladino et al. present an intriguing hypothesis surrounding the role of formamide in the origins of life on Earth, backed by experimental results supporting each step from formamide to RNA polymers. The overall premise is that, from formamide and inorganic phosphate, RNA molecules over 100 nucleotides in length can be produced. In addition, many carboxylic acids likely relevant to prebiotic metabolism, are formed along the way. Thus, from a rather simple organic molecule that has been observed in outer space (formamide), you can generate many of the compounds necessary for the origins of life. However, because high temperatures (160 C) are required for the formamide reactions, it remains unclear where the "warm formamide" scenario could have occurred. Low-temperature, aqueous hydrogen cyanide-based prebiotic chemistry that we know actually happened has been shown to produce many of the molecules invoked in the formamide hypothesis: amino acids, carboxylic acids, sugar acids, and nucleobases have all been found in meteorites recovered on Earth, providing a plausible route for their synthesis and delivery. In contrast, a large portion of the formamide hypothesis is based on relatively hightemperature reactions, A plausible milieu for high-temperature reactions with concentrated formamide is yet to be described, and is critical for this hypothesis to be validated. Hydrothermal vents are attractive heat sources, and the higher boiling point of formamide has been invoked as a mechanism to concentrate it from an aqueous solution, Unless the water can actually evaporate, however, there would be no net enrichment. For example, in the context of a deep-sea vent, any water "removed" by heating would be quickly replaced. Some of the individual reactions underpinning the present hypothesis have been met with skepticism because they go against conventional wisdom, To name a few of the surprising results: the observation that nucleosides can be converted to cyclic phosphates when heated in the presence of minerals and inorganie phosphate; that 3'-5' cGMP and cAMP nucleotides polymerize rapidly into RNA oligomers, even in the absence of monovalent counterions and that end-to-end ligation reactions between RNA oligomers occur in essentially pure water, without requiring any activating groups or counterions. Because the polymerization reactions are simply transesterification reactions, that they readily occur in the absence of cations makes one wonder why nearly all ribozyme-catalyzed transesterification reactions are metal-ion dependent; similarly, that the end-to-end ligation reactions do not require activation runs counter to the observation that all protein-catalyzed ligation and polymerization reactions of RNA and DNA require activated substrates. Detailed mechanistic studies of the reported reactions are warranted and could provide important insights for understanding the chemistry behind the origins of life. Because the authors have produced many of the experimental results supporting their hypothesis, they could demonstrate the validity of their hypothesis by converting formamide into approx 100 nucleotide RNA oligomers, using the products of one reaction as the reactants for the next reaction, under specific conditions plausible on the pre-biotic Earth. Such a demonstration would represent a milestone for our understanding of the origins of life.

Synthesis of fatty acid methyl ester from the transesterification of high- and low-acid-content crude palm oil (Elaeis guineensis) and karanj oil (Pongamia pinnata) over a calcium-lanthanum-aluminum mixed-oxides catalyst.

PubMed

Syamsuddin, Y; Murat, M N; Hameed, B H

2016-08-01

The synthesis of fatty acid methyl ester (FAME) from the high- and low-acid-content feedstock of crude palm oil (CPO) and karanj oil (KO) was conducted over CaO-La2O3-Al2O3 mixed-oxide catalyst. Various reaction parameters were investigated using a batch reactor to identify the best reaction condition that results in the highest FAME yield for each type of oil. The transesterification of CPO resulted in a 97.81% FAME yield with the process conditions of 170°C reaction temperature, 15:1 DMC-to-CPO molar ratio, 180min reaction time, and 10wt.% catalyst loading. The transesterification of KO resulted in a 96.77% FAME yield with the conditions of 150°C reaction temperature, 9:1 DMC-to-KO molar ratio, 180min reaction time, and 5wt.% catalyst loading. The properties of both products met the ASTM D6751 and EN 14214 standard requirements. The above results showed that the CaO-La2O3-Al2O3 mixed-oxide catalyst was suitable for high- and low-acid-content vegetable oil. Copyright © 2016 Elsevier Ltd. All rights reserved.

Novel utilization of waste marine sponge (Demospongiae) as a catalyst in ultrasound-assisted transesterification of waste cooking oil.

PubMed

Hindryawati, Noor; Maniam, Gaanty Pragas

2015-01-01

This study demonstrates the potential of Na-silica waste sponge as a source of low cost catalyst in the transesterification of waste cooking oil aided by ultrasound. In this work an environmentally friendly and efficient transesterification process using Na-loaded SiO2 from waste sponge skeletons as a solid catalyst is presented. The results showed that the methyl esters content of 98.4±0.4wt.% was obtainable in less than an hour (h) of reaction time at 55°C. Optimization of reaction parameters revealed that MeOH:oil, 9:1; catalyst, 3wt.% and reaction duration of 30min as optimum reaction conditions. The catalyst is able to tolerant free fatty acid and moisture content up to 6% and 8%, respectively. In addition, the catalyst can be reused for seven cycles while maintaining the methyl esters content at 86.3%. Ultrasound undoubtedly assisted in achieving this remarkable result in less than 1h reaction time. For the kinetics study at 50-60°C, a pseudo first order model was proposed, and the activation energy of the reaction is determined as 33.45kJ/mol using Arrhenius equation. Copyright © 2014 Elsevier B.V. All rights reserved.

Electrochemical method for producing a biodiesel mixture comprising fatty acid alkyl esters and glycerol

DOEpatents

Lin, YuPo J; St. Martin, Edward J

2013-08-13

The present invention relates to an integrated method and system for the simultaneous production of biodiesel from free fatty acids (via esterification) and from triglycerides (via transesterification) within the same reaction chamber. More specifically, one preferred embodiment of the invention relates to a method and system for the production of biodiesel using an electrodeionization stack, wherein an ion exchange resin matrix acts as a heterogeneous catalyst for simultaneous esterification and transesterification reactions between a feedstock and a lower alcohol to produce biodiesel, wherein the feedstock contains significant levels of free fatty acid. In addition, because of the use of a heterogeneous catalyst, the glycerol and biodiesel have much lower salt concentrations than raw biodiesel produced by conventional transesterification processes. The present invention makes it much easier to purify glycerol and biodiesel.

Role of solid acid catalysts in bio diesel production.

PubMed

Shivayogimath, C B; Sunita, G; Manoj Kumar, B

2009-07-01

Biodiesel is gaining importance as an alternate source of attractive fuel because of depleting fossil fuel resources. It is produced by trans-esterification, in which oil or fat reacts with a monohydric alcohol in presence of a catalyst. In the present work, trans-esterification of sunflower oil with methanol is carried out by using zirconia supported isopoly and heteropoly tungstates (HPAs) as catalysts. Effects of reaction parameters, such as catalyst types and its concentration, molar ratio of sunflower oil to methanol, reaction temperature and time, have been optimized to get higher conversion of sunflower oil and the product distribution of fatty acid methyl esters (FAME) in the trans-esterfication reaction.

Mechanistic Insights into RNA Transphosphorylation from Kinetic Isotope Effects and Linear Free Energy Relationships of Model Reactions

PubMed Central

Chen, Haoyuan; Giese, Timothy J.; Huang, Ming; Wong, Kin-Yiu; Harris, Michael E.; York, Darrin M.

2015-01-01

Phosphoryl transfer reactions are ubiquitous in biology, and the understanding of the mechanisms whereby these reactions are catalyzed by protein and RNA enzymes is central to reveal design principles for new therapeutics. Two of the most powerful experimental probes of chemical mechanism involve the analysis of linear free energy relations (LFERs) and the measurement of kinetic isotope effects (KIEs). These experimental data report directly on differences in bonding between the ground state and the rate-controlling transition state, which is the most critical point along the reaction free energy pathway. However, interpretation of LFER and KIE data in terms of transition state structure and bonding optimally requires the use of theoretical models. In this work, we apply density-functional calculations to determine KIEs for a series of phosphoryl transfer reactions of direct relevance to the 2’-O-transphosphorylation that leads to cleavage of the phosphodiester backbone of RNA. We first examine a well-studied series of phosphate and phosphorothioate mono-, di- and triesters that are useful as mechanistic probes and for which KIEs have been measured. Close agreement is demonstrated between the calculated and measured KIEs, establishing the reliability of our quantum model calculations. Next, we examine a series of RNA transesterification model reactions with a wide range of leaving groups in order to provide a direct connection between observed Brønsted coefficients and KIEs with the structure and bonding in the transition state. These relations can be used for prediction or to aid in the interpretation of experimental data for similar non-enzymatic and enzymatic reactions. Finally, we apply these relations to RNA phosphoryl transfer catalyzed by ribonuclease A, and demonstrate the reaction coordinate-KIE correlation is reasonably preserved. A prediction of the secondary deuterium KIE in this reaction is also provided. These results demonstrate the utility of building up knowledge of mechanism through the systematic study of model systems to provide insight into more complex biological systems such as phosphoryl transfer enzymes and ribozymes. PMID:25223953

Mechanistic insights into RNA transphosphorylation from kinetic isotope effects and linear free energy relationships of model reactions.

PubMed

Chen, Haoyuan; Giese, Timothy J; Huang, Ming; Wong, Kin-Yiu; Harris, Michael E; York, Darrin M

2014-10-27

Phosphoryl transfer reactions are ubiquitous in biology and the understanding of the mechanisms whereby these reactions are catalyzed by protein and RNA enzymes is central to reveal design principles for new therapeutics. Two of the most powerful experimental probes of chemical mechanism involve the analysis of linear free energy relations (LFERs) and the measurement of kinetic isotope effects (KIEs). These experimental data report directly on differences in bonding between the ground state and the rate-controlling transition state, which is the most critical point along the reaction free energy pathway. However, interpretation of LFER and KIE data in terms of transition-state structure and bonding optimally requires the use of theoretical models. In this work, we apply density-functional calculations to determine KIEs for a series of phosphoryl transfer reactions of direct relevance to the 2'-O-transphosphorylation that leads to cleavage of the phosphodiester backbone of RNA. We first examine a well-studied series of phosphate and phosphorothioate mono-, di- and triesters that are useful as mechanistic probes and for which KIEs have been measured. Close agreement is demonstrated between the calculated and measured KIEs, establishing the reliability of our quantum model calculations. Next, we examine a series of RNA transesterification model reactions with a wide range of leaving groups in order to provide a direct connection between observed Brønsted coefficients and KIEs with the structure and bonding in the transition state. These relations can be used for prediction or to aid in the interpretation of experimental data for similar non-enzymatic and enzymatic reactions. Finally, we apply these relations to RNA phosphoryl transfer catalyzed by ribonuclease A, and demonstrate the reaction coordinate-KIE correlation is reasonably preserved. A prediction of the secondary deuterium KIE in this reaction is also provided. These results demonstrate the utility of building up knowledge of mechanism through the systematic study of model systems to provide insight into more complex biological systems such as phosphoryl transfer enzymes and ribozymes. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Concurrent extraction and reaction for the production of biodiesel from wet microalgae.

PubMed

Im, Hanjin; Lee, HanSol; Park, Min S; Yang, Ji-Won; Lee, Jae W

2014-01-01

This work addresses a reliable in situ transesterification process which integrates lipid extraction from wet microalgae, and its conversion to biodiesel, with a yield higher than 90 wt.%. This process enables single-step production of biodiesel from microalgae by mixing wet microalgal cells with solvent, methanol, and acid catalyst; and then heating them in one pot. The effects of reaction parameters such as reaction temperature, wet cell weight, reaction time, and catalyst volume on the conversion yield are investigated. This simultaneous extraction and transesterification of wet microalgae may enable a significant reduction in energy consumption by eliminating the drying process of algal cells and realize the economic production of biodiesel using wet microalgae. Copyright © 2013 Elsevier Ltd. All rights reserved.

Biodiesel production from rice bran oil by transesterification using heterogeneous catalyst natural zeolite modified with K2CO3

NASA Astrophysics Data System (ADS)

Taslim; Iriany; Bani, O.; Parinduri, S. Z. D. M.; Ningsih, P. R. W.

2018-02-01

In the present study, an effort had been made to use natural zeolite from Tapanuli Utara, North Sumatera as a potential catalyst for biodiesel production. Biodiesel production is usuallythrough transesterification, and a catalyst is employed to improve reaction rate and yield. In this research rice bran oil (RBO) was used as feedstock. The objective of this work was to discover the effectiveness of natural zeolite modified by K2CO3 as catalysts in biodiesel production from RBO. K2CO3/natural zeolite catalyst modification was by impregnation method at various K2CO3 concentrations followed by drying and calcination. Transesterification was conducted at 65°C and 500 rpm. Effect of process variables such as the amount of catalyst, reaction time, and the molar ratio of methanol to RBO was investigated.The maximum yield of 98.18% biodiesel was obtained by using 10:1 molar ratio of methanol to RBO at a reaction time of 3 hours in the presence of 4 w% catalyst. The obtained biodiesel was then characterized by its density, viscosity and ester content. The biodiesel properties met the Indonesia standard (SNI).The results showed that natural zeolite modified by K2CO3 was suitable as a catalyst in the synthesis of biodiesel through transesterification from RBO.

The utilization of leftover as acid catalyst to catalyse the transesterification and esterification reactions

NASA Astrophysics Data System (ADS)

Leung, K. K.; Yau, Y. H.

2017-08-01

Biodiesel (Fatty Acid Methyl Ester, FAME) is a green and renewable energy. It is carbon neutral and produces less air pollutants in combustion. In my project, the selected feedstock of biodiesel production is grease trap oil (GTO). It is extracted from restaurants, and needs pre-treatment. The triglycerides and free fatty acid (FFA) are the main components of GTO. Both triglycerides and free fatty acid can be converted to biodiesel (Fatty Acid Methyl Ester) by transesterification and esterification, through reaction with alcohol (methanol) and catalyst. In the processes, acidic catalyst is chosen to speed up the reactions. The catalyst used In the study, a heterogeneous solid acid is applied. It is waste cooked rice (WCR) collected from leftover. The WCR powder is pyrolysed in 400°C furnace 15 hours and blown with nitrogen gas (incomplete carbonization). The WCR black powder is then mixed with concentrated sulphuric acid and heat in 160°C furnace 15 hours and continuous blown with nitrogen gas (sulphonation). This heterogeneous solid acid is used in the both transesterification and esterification to produce FAME. Moreover, in the optimal reaction conditions, this catalyst offers a stable catalytic effect. After 20 times usage in optimal reaction condition, the catalytic activity remains unchanged.

In-situ transesterification of seeds of invasive Chinese tallow trees (Triadica sebifera L.) in a microwave batch system (GREEN(3)) using hexane as co-solvent: Biodiesel production and process optimization.

PubMed

Barekati-Goudarzi, Mohamad; Boldor, Dorin; Nde, Divine B

2016-02-01

In-situ transesterification (simultaneous extraction and transesterification) of Chinese tallow tree seeds into methyl esters using a batch microwave system was investigated in this study. A high degree of oil extraction and efficient conversion of oil to biodiesel were found in the proposed range. The process was further optimized in terms of product yields and conversion rates using Doehlert optimization methodology. Based on the experimental results and statistical analysis, the optimal production yield conditions for this process were determined as: catalyst concentration of 1.74wt.%, solvent ratio about 3 (v/w), reaction time of 20min and temperature of 58.1°C. H(+)NMR was used to calculate reaction conversion. All methyl esters produced using this method met ASTM biodiesel quality specifications. Copyright © 2015 Elsevier Ltd. All rights reserved.

CaO Nanocatalyst for Transesterification Reaction of Palm Oil to Biodiesel: Effect of Precursor’s Concentration on the Catalyst Behavior

NASA Astrophysics Data System (ADS)

Hassan, N.; Ismail, K. N.; Hamid, K. H. Ku; Hadi, Abdul

2018-05-01

Depletion of fossil fuel sources in a few decades due to industrialization and motorization has led to a keen interest in the production of alternative fuels like biodiesel. Research on the development and improvement of more efficient transesterification process for biodiesel production has attain great attention in the last decade. The using of low cost catalyst is one of the main focuses on the biodiesel production. As a basic heterogeneous catalyst, CaO has been examined in the transesterification of vegetable oils for biodiesel production. In this research, calcium oxide (CaO-X) catalysts were prepared by sol-gel method at different Ca2+ precursor concentration (X = 1.0, 1.5, 2.0 M). The crystalline structure and morphology of the synthesized catalysts were characterized by means of x-ray diffraction (XRD) and N2 adsorption-desorption analysis. All the synthesized catalysts were then applied to transesterification reaction of palm oil to produce biodiesel. The characterization by x-ray diffraction demonstrate CaO-1.0 was partially hydrated due to the incomplete reaction during synthesis. As a matter of fact, formation of H2O on the surface of CaO causes lower basic strength of the catalysts, thus responsible in lowering the catalytic activity. It is demonstrated that CaO-2.0 exhibits mesoporous structure with least chemisorb amount of H2O on the catalysts surface has a very active catalytic activity. It was found that 2.0M of calcium precursor has high catalytic activity and 81% FAME yield was obtained within 3h reaction.

Process optimization and kinetics of biodiesel production from neem oil using copper doped zinc oxide heterogeneous nanocatalyst.

PubMed

Gurunathan, Baskar; Ravi, Aiswarya

2015-08-01

Heterogeneous nanocatalyst has become the choice of researchers for better transesterification of vegetable oils to biodiesel. In the present study, transesterification reaction was optimized and kinetics was studied for biodiesel production from neem oil using CZO nanocatalyst. The highly porous and non-uniform surface of the CZO nanocatalyst was confirmed by AFM analysis, which leads to the aggregation of CZO nanoparticles in the form of multi layered nanostructures. The 97.18% biodiesel yield was obtained in 60min reaction time at 55°C using 10% (w/w) CZO nanocatalyst and 1:10 (v:v) oil:methanol ratio. Biodiesel yield of 73.95% was obtained using recycled nanocatalyst in sixth cycle. The obtained biodiesel was confirmed using GC-MS and (1)H NMR analysis. Reaction kinetic models were tested on biodiesel production, first order kinetic model was found fit with experimental data (R(2)=0.9452). The activation energy of 233.88kJ/mol was required for transesterification of neem oil into biodiesel using CZO nanocatalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

Preparation and characterizaton of CaO nanoparticle for biodiesel production

NASA Astrophysics Data System (ADS)

Gupta, Jharna; Agarwal, Madhu

2016-04-01

Nanoparticle of CaO from calcium Nitrate (CaO/CaN) and Snail shell (CaO/SS) are successfully synthesized by method as described in the literature and used as an active and stable catalyst for the biodiesel production. These catalysts are characterized by Fourier-transform infrared spectra (FT-IR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The average crystalline size in nanometer was also calculated by Debye-Scherrer equation. The performance of the CaO/CaN and CaO/SS were tested for their catalytic activity via transesterification process and it was found that biodiesel yield has been increased from 93 to 96%. The optimum conditions for the highest yield were 8wt% catalyst loading, 65°C temperature, 12:1 methanol/oil molar ratio, and 6 h for reaction time. The nano catalyst from snail shell exhibits excellent catalytic activity and stability for the transesterification reaction, which suggested that this catalyst would be potentially used as a solid base nano catalyst for biodiesel production. In order to examine the reusability of catalyst developed from snail shell, five transesterification reaction cycles were also performed.

Microwave Energy Increases Fatty Acid Methyl Ester Yield in Human Whole Blood Due to Increased Sphingomyelin Transesterification.

PubMed

Metherel, Adam H; Aristizabal Henao, Juan J; Ciobanu, Flaviu; Taha, Ameer Y; Stark, Ken D

2015-09-01

Dried blood spots (DBS) by fingertip prick collection for fatty acid profiling are becoming increasingly popular due to ease of collection, minimal invasiveness and its amenability to high-throughput analyses. Herein, we assess a microwave-assisted direct transesterification method for the production of fatty acid methyl esters (FAME) from DBS. Technical replicates of human whole blood were collected and 25-μL aliquots were applied to chromatography strips prior to analysis by a standard 3-h transesterification method or microwave-assisted direct transesterification method under various power (variable vs constant), time (1-5 min) and reagent (1-10% H2SO4 in methanol) conditions. In addition, a standard method was compared to a 5-min, 30-W power microwave in 1% H2SO4 method for FAME yield from whole blood sphingomyelin, and sphingomyelin standards alone and spiked in whole blood. Microwave-assisted direct transesterification yielded no significant differences in both quantitative (nmol/100 µL) and qualitative (mol%) fatty acid assessments after as little as 1.5- and 1-min reaction times, respectively, using the variable power method and 5% H2SO4 in methanol. However, 30-W power for 5 min increased total FAME yield of the technical replicates by 14%. This increase appears largely due to higher sphingomyelin-derived FAME yield of up to 109 and 399% compared to the standard method when determined from whole blood or pure standards, respectively. In conclusion, microwave-assisted direct transesterification of DBS achieved in as little as 1-min, and 5-min reaction times increase total fatty acids primarily by significantly improving sphingomyelin-derived fatty acid yield.

CaFeAl mixed oxide derived heterogeneous catalysts for transesterification of soybean oil to biodiesel.

PubMed

Lu, Yongsheng; Zhang, Zaiwu; Xu, Yunfeng; Liu, Qiang; Qian, Guangren

2015-08-01

CaAl layered double oxides (LDO) were prepared by co-precipitation and calcined at 750°C, and then applied to biodiesel production by transesterification reaction between methanol and soybean oil. Compared with characteristics of CaFe/LDO and CaAl/LDO, CaFeAl/LDO had the best performance based on prominent catalytic activity and stability, and achieved over 90% biodiesel yield, which stayed stable (over 85%) even after 8 cycles of reaction. The optimal catalytic reaction condition was 12:1M-ratio of methanol/oil, reaction temperatures of 60°C, 270rpm stirring rate, 60min reaction time, and 6% weight-ratio of catalyst/oil. In addition, the CaFeAl/LDO catalyst is insoluble in both methanol and methyl esters and can be easily separated for further reaction, turning it into an excellent alternative for biodiesel synthesis. Copyright © 2015 Elsevier Ltd. All rights reserved.

New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel†

PubMed Central

Zhao, Hua; Baker, Gary A.; Holmes, Shaletha

2012-01-01

The enzymatic preparation of biodiesel has been hampered by the lack of suitable solvents with desirable properties such as high lipase compatibility, low cost, low viscosity, high biodegradability, and ease of product separation. Recent interest in using ionic liquids (ILs) as advanced reaction media has led to fast reaction rates and high yields in the enzymatic synthesis of biodiesel. However, conventional (i.e., cation–anion paired) ILs based on imidazolium and other quaternary ammonium salts remain too expensive for wide application at industrial scales. In this study, we report on newly-synthesized eutectic ILs derived from choline acetate or choline chloride coupled with biocompatible hydrogen-bond donors, such as glycerol. These eutectic solvents have favorable properties including low viscosity, high biodegradability, and excellent compatibility with Novozym® 435, a commercial immobilized Candida antarctica lipase B. Furthermore, in a model biodiesel synthesis system, we demonstrate high reaction rates for the enzymatic transesterification of Miglyol® oil 812 with methanol, catalyzed by Novozym® 435 in choline acetate/glycerol (1 : 1.5 molar ratio). The high conversion (97%) of the triglyceride obtained within 3 h, under optimal conditions, suggests that these novel eutectic solvents warrant further exploration as potential media in the enzymatic production of biodiesel. PMID:21283901

Effect of alcohol on skin permeation and metabolism of an ester-type prodrug in Yucatan micropig skin.

PubMed

Fujii, Makiko; Ohara, Rieko; Matsumi, Azusa; Ohura, Kayoko; Koizumi, Naoya; Imai, Teruko; Watanabe, Yoshiteru

2017-11-15

We studied the effect that three alcohols, ethanol (EA), propanol (PA), and isopropanol (IPA), have on the skin permeation of p-hydroxy benzoic acid methyl ester (HBM), a model ester-type prodrug. HBM was applied to Yucatan micropig skin in a saturated phosphate buffered solution with or without 10% alcohol, and HBM and related materials in receptor fluid and skin were determined with HPLC. In the absence of alcohol, p-hydroxy benzoic acid (HBA), a metabolite of HBM, permeated the skin the most. The three alcohols enhanced the penetration of HBM at almost the same extent. The addition of 10% EA or PA to the HBM solution led to trans-esterification into the ethyl ester or propyl ester of HBA, and these esters permeated skin as well as HBA and HBM did. In contrast, the addition of 10% IPA promoted very little trans-esterification. Both hydrolysis and trans-esterification in the skin S9 fraction were inhibited by BNPP, an inhibitor of carboxylesterase (CES). Western blot and native PAGE showed the abundant expression of CES in micropig skin. Both hydrolysis and trans-esterification was simultaneously catalyzed by CES during skin permeation. Our data indicate that the alcohol used in dermal drug preparations should be selected not only for its ability to enhance the solubility and permeation of the drug, but also for the effect on metabolism of the drug in the skin. Copyright © 2017 Elsevier B.V. All rights reserved.

Recombinant Lipases and Phospholipases and Their Use as Biocatalysts for Industrial Applications

PubMed Central

Borrelli, Grazia M.; Trono, Daniela

2015-01-01

Lipases and phospholipases are interfacial enzymes that hydrolyze hydrophobic ester linkages of triacylglycerols and phospholipids, respectively. In addition to their role as esterases, these enzymes catalyze a plethora of other reactions; indeed, lipases also catalyze esterification, transesterification and interesterification reactions, and phospholipases also show acyltransferase, transacylase and transphosphatidylation activities. Thus, lipases and phospholipases represent versatile biocatalysts that are widely used in various industrial applications, such as for biodiesels, food, nutraceuticals, oil degumming and detergents; minor applications also include bioremediation, agriculture, cosmetics, leather and paper industries. These enzymes are ubiquitous in most living organisms, across animals, plants, yeasts, fungi and bacteria. For their greater availability and their ease of production, microbial lipases and phospholipases are preferred to those derived from animals and plants. Nevertheless, traditional purification strategies from microbe cultures have a number of disadvantages, which include non-reproducibility and low yields. Moreover, native microbial enzymes are not always suitable for biocatalytic processes. The development of molecular techniques for the production of recombinant heterologous proteins in a host system has overcome these constraints, as this allows high-level protein expression and production of new redesigned enzymes with improved catalytic properties. These can meet the requirements of specific industrial process better than the native enzymes. The purpose of this review is to give an overview of the structural and functional features of lipases and phospholipases, to describe the recent advances in optimization of the production of recombinant lipases and phospholipases, and to summarize the information available relating to their major applications in industrial processes. PMID:26340621

Recombinant Lipases and Phospholipases and Their Use as Biocatalysts for Industrial Applications.

PubMed

Borrelli, Grazia M; Trono, Daniela

2015-09-01

Lipases and phospholipases are interfacial enzymes that hydrolyze hydrophobic ester linkages of triacylglycerols and phospholipids, respectively. In addition to their role as esterases, these enzymes catalyze a plethora of other reactions; indeed, lipases also catalyze esterification, transesterification and interesterification reactions, and phospholipases also show acyltransferase, transacylase and transphosphatidylation activities. Thus, lipases and phospholipases represent versatile biocatalysts that are widely used in various industrial applications, such as for biodiesels, food, nutraceuticals, oil degumming and detergents; minor applications also include bioremediation, agriculture, cosmetics, leather and paper industries. These enzymes are ubiquitous in most living organisms, across animals, plants, yeasts, fungi and bacteria. For their greater availability and their ease of production, microbial lipases and phospholipases are preferred to those derived from animals and plants. Nevertheless, traditional purification strategies from microbe cultures have a number of disadvantages, which include non-reproducibility and low yields. Moreover, native microbial enzymes are not always suitable for biocatalytic processes. The development of molecular techniques for the production of recombinant heterologous proteins in a host system has overcome these constraints, as this allows high-level protein expression and production of new redesigned enzymes with improved catalytic properties. These can meet the requirements of specific industrial process better than the native enzymes. The purpose of this review is to give an overview of the structural and functional features of lipases and phospholipases, to describe the recent advances in optimization of the production of recombinant lipases and phospholipases, and to summarize the information available relating to their major applications in industrial processes.

"New" Compounds from Old Plastics: Recycling PET Plastics via Depolymerization. An Activity for the Undergraduate Organic Lab

NASA Astrophysics Data System (ADS)

Kaufman, Don; Wright, Geoff; Kroemer, Ryan; Engel, Josh

1999-11-01

This paper describes work done to develop a meaningful undergraduate organic lab activity that illustrates chemistry of the real world while utilizing reactions typically included in the organic lecture and lab. We show how a common plastic can be converted into several compounds using ester hydrolysis and SN2 reactions. Contributing to the critical shortage of landfill space faced by many communities is the large quantity of plastic refuse. Thus, there is a real need to recycle plastic products. One way to recycle plastics such as polyethyleneterephthalate (PET), the polyester from which numerous consumer products such as 2-liter soda bottles are made, is to depolymerize them and then to use the resulting monomers to produce new products. PET is industrially depolymerized via an acid-catalyzed transesterification reaction conducted under conditions of high temperature and pressure that are not feasible in the undergraduate lab. Despite literature reports that PET is remarkably resistant to hydrolysis, we found that PET can be readily hydrolyzed by refluxing with potassium hydroxide or potassium tert-butoxide in amyl alcohol to give terephthalic acid in high yield. It is then possible to readily synthesize terephthalate diesters via SN2 reactions of ammonium terephthalate salts with alkyl halides. Fischer esterification can also be used to prepare the diesters, but yields are significantly lower.

Kinetics of enzymatic trans-esterification of glycerides for biodiesel production.

PubMed

Calabrò, Vincenza; Ricca, Emanuele; De Paola, Maria Gabriela; Curcio, Stefano; Iorio, Gabriele

2010-08-01

In this paper, the reaction of enzymatic trans-esterification of glycerides with ethanol in a reaction medium containing hexane at a temperature of 37 degrees C has been studied. The enzyme was Lipase from Mucor miehei, immobilized on ionic exchange resin, aimed at achieving high catalytic specific surface and recovering, regenerating and reusing the biocatalyst. A kinetic analysis has been carried out to identify the reaction path; the rate equation and kinetic parameters have been also calculated. The kinetic model has been validated by comparison between predicted and experimental results. Mass transport resistances estimation was undertaken in order to verify that the kinetics found was intrinsic. Model potentialities in terms of reactors design and optimization are also shown.

21 CFR 172.270 - Sulfated butyl oleate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... transesterification of an edible vegetable oil using 1-butanol. Following sulfation, the reaction mixture is washed... oleate reaction mixture meets the following specifications: (1) Not less than 90 percent butyl oleate. (2...

Production of Omega-3 Fatty Acid Ethyl Esters from Menhaden Oil Using Proteus vulgaris Lipase-Mediated One-Step Transesterification and Urea Complexation.

PubMed

Kim, Soo-Jin; Kim, Hyung Kwoun

2016-05-01

An organic solvent-stable lipase from Proteus vulgaris K80 was used to produce the omega-3 polyunsaturated fatty acid ethyl esters (ω-3 PUFA EEs). First, the lyophilized recombinant lipase K80 (LyoK80) was used to perform the transesterification reaction of menhaden oil and ethanol. LyoK80 produced the ω-3 PUFA EEs with a conversion yield of 82 % in the presence of 20 % water content via a three-step ethanol-feeding process; however, in a non-aqueous condition, LyoK80 produced only a slight amount of the ω-3 PUFA EEs. To enhance its reaction properties, the lipase K80 was immobilized on a hydrophobic bead to derive ImmK80; the biochemical properties and substrate specificity of ImmK80 are similar to those of LyoK80. ImmK80 was then used to produce ω-3 PUFA EEs in accordance with the same transesterification reaction. Unlike LyoK80, ImmK80 achieved a high ω-3 PUFA EE conversion yield of 86 % under a non-aqueous system via a one-step ethanol-feeding reaction. The ω-3 PUFA EEs were purified up to 92 % using a urea complexation method.

Effect of reaction temperature on biodiesel production from waste cooking oil using lipase as biocatalyst

NASA Astrophysics Data System (ADS)

Istiningrum, Reni Banowati; Aprianto, Toni; Pamungkas, Febria Lutfi Udin

2017-12-01

This study aims to determine the effect of temperature on conversion of biodiesel from waste cooking oil enzymatically using lipase extracted from rice bran. The feedstock was simulated waste cooking oil and lipase enzyme was extracted with buffer pH variation. The enzyme activity was titrimetrically determined and the optimum pH buffer was used to study the effect of temperature on the transesterification reaction. Temperature effects were assessed in the range of 45-60 °C and the content of methyl esters in biodiesel was determined by GC-MS. The reaction temperature significantly influences the transesterification reaction with optimum biodiesel conversion occurred at 55 °C with methyl ester content of 81.19%. The methyl ester composition in the resulting biodiesel is methyl palmitate, methyl oleate and methyl stearate.

Efficient synthetic protocols in glycerol under heterogeneous catalysis.

PubMed

Cravotto, Giancarlo; Orio, Laura; Gaudino, Emanuela Calcio; Martina, Katia; Tavor, Dorith; Wolfson, Adi

2011-08-22

The massive increase in glycerol production from the transesterification of vegetable oils has stimulated a large effort to find novel uses for this compound. Hence, the use of glycerol as a solvent for organic synthesis has drawn particular interest. Drawbacks of this green and renewable solvent are a low solubility of highly hydrophobic molecules and a high viscosity, which often requires the use of a fluidifying co-solvent. These limitations can be easily overcome by performing reactions under high-intensity ultrasound and microwaves in a stand-alone or combined manner. These non-conventional techniques facilitate and widen the use of glycerol as a solvent in organic synthesis. Glycerol allows excellent acoustic cavitation even at high temperatures (70-100 °C), which is otherwise negligible in water. Herein, we describe three different types of applications: 1) the catalytic transfer hydrogenation of benzaldehyde to benzyl alcohol in which glycerol plays the dual role of the solvent and hydrogen donor; 2) the palladium-catalyzed Suzuki cross-coupling; and (3) the Barbier reaction. In all cases glycerol proved to be a greener, less expensive, and safer alternative to the classic volatile organic solvents. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Two-Stage Conversion of High Free Fatty Acid Jatropha curcas Oil to Biodiesel Using Brønsted Acidic Ionic Liquid and KOH as Catalysts

PubMed Central

Das, Subrata; Thakur, Ashim Jyoti; Deka, Dhanapati

2014-01-01

Biodiesel was produced from high free fatty acid (FFA) Jatropha curcas oil (JCO) by two-stage process in which esterification was performed by Brønsted acidic ionic liquid 1-(1-butylsulfonic)-3-methylimidazolium chloride ([BSMIM]Cl) followed by KOH catalyzed transesterification. Maximum FFA conversion of 93.9% was achieved and it reduced from 8.15 wt% to 0.49 wt% under the optimum reaction conditions of methanol oil molar ratio 12 : 1 and 10 wt% of ionic liquid catalyst at 70°C in 6 h. The ionic liquid catalyst was reusable up to four times of consecutive runs under the optimum reaction conditions. At the second stage, the esterified JCO was transesterified by using 1.3 wt% KOH and methanol oil molar ratio of 6 : 1 in 20 min at 64°C. The yield of the final biodiesel was found to be 98.6% as analyzed by NMR spectroscopy. Chemical composition of the final biodiesel was also determined by GC-MS analysis. PMID:24987726

Biodiesel production from microbial oil derived from wood isolate Trichoderma reesei.

PubMed

Bharathiraja, B; Sowmya, V; Sridharan, Sridevi; Yuvaraj, D; Jayamuthunagai, J; Praveenkumar, R

2017-09-01

In the present study Trichoderma reesei, a wood isolate can yield high biomass quantities up to 30g/L, yielding 32.4% of lipids of dry cell weight (DCW). Biodiesel production from Trichoderma reesei involved simple unit operations like filtration and ultrasonication, yet giving good lipid yield with desirable bio-diesel properties. Optimization of ultrasonication conditions was done to ensure maximum lipid extraction. SEM analysis of ultrasonicated samples showed distinct breakage of fungal hyphae. The lipids were found to contain 49.7% saturated fatty acids. Transesterification using chemical and biological catalysts were compared and 96.09% efficiency was observed for lipase-catalyzed transesterification. The bio-diesel properties satisfied ASTM and EN specifications with cetane number: 53.1, iodine value: 63.34g, saponification value: 235.07mg KOH/g, cold flow plugging point: 9.13°C. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of biodiesel production in a hydrodynamic cavitation reactor using used frying oil.

PubMed

Ghayal, Dyneshwar; Pandit, Aniruddha B; Rathod, Virendra K

2013-01-01

The present work demonstrates the application of a hydrodynamic cavitation reactor for the synthesis of biodiesel with used frying oil as a feedstock. The synthesis involved the transesterification of used frying oil (UFO) with methanol in the presence of potassium hydroxide as a catalyst. The effect of geometry and upstream pressure of a cavitating orifice plate on the rate of transesterification reaction has been studied. It is observed that the micro level turbulence created by hydrodynamic cavitation somewhat overcomes the mass transfer limitations for triphasic transesterification reaction. The significant effects of upstream pressure on the rate of formation of methyl esters have been seen. It has been observed that flow geometry of orifice plate plays a crucial role in process intensification. With an optimized plate geometry of 2mm hole diameter and 25 holes, more than 95% of triglycerides have been converted to methyl esters in 10 min of reaction time with cavitational yield of 1.28 × 10(-3) (Grams of methyl esters produced per Joule of energy supplied). The potential of UFO to produce good quality methyl esters has been demonstrated. Copyright © 2012 Elsevier B.V. All rights reserved.

Preparation and characterizaton of CaO nanoparticle for biodiesel production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gupta, Jharna, E-mail: onlinejharna@gmail.com; Agarwal, Madhu, E-mail: madhunaresh@gmail.com

Nanoparticle of CaO from calcium Nitrate (CaO/CaN) and Snail shell (CaO/SS) are successfully synthesized by method as described in the literature and used as an active and stable catalyst for the biodiesel production. These catalysts are characterized by Fourier-transform infrared spectra (FT-IR), X-ray diffraction (XRD), and thermal gravimetric analysis (TGA). The average crystalline size in nanometer was also calculated by Debye–Scherrer equation. The performance of the CaO/CaN and CaO/SS were tested for their catalytic activity via transesterification process and it was found that biodiesel yield has been increased from 93 to 96%. The optimum conditions for the highest yield weremore » 8wt% catalyst loading, 65°C temperature, 12:1 methanol/oil molar ratio, and 6 h for reaction time. The nano catalyst from snail shell exhibits excellent catalytic activity and stability for the transesterification reaction, which suggested that this catalyst would be potentially used as a solid base nano catalyst for biodiesel production. In order to examine the reusability of catalyst developed from snail shell, five transesterification reaction cycles were also performed.« less

Synthesis and emulsifying properties of carbohydrate fatty acid esters produced from Agave tequilana fructans by enzymatic acylation.

PubMed

Casas-Godoy, Leticia; Arrizon, Javier; Arrieta-Baez, Daniel; Plou, Francisco J; Sandoval, Georgina

2016-08-01

Carbohydrate fatty acid esters are non-ionic surfactants with a broad spectrum of applications. These molecules are generally synthesized using short carbohydrates or linear fructans; however in this research carbohydrate fatty acid esters were produced for the first time with branched fructans from Agave tequilana. Using immobilized lipases we successfully acylated A. tequilana fructans with vinyl laurate, obtaining products with different degrees of polymerization (DP). Lipozyme 435 was the most efficient lipase to catalyze the transesterification reaction. HPLC and ESI-MS analysis proved the presence of a mixture of acylated products as a result of the chemical complexity of fructans in the A. tequilana. The ESI-MS spectra showed a molecular mass shift between 183 and 366g/mol for fructooligosaccharides with a DP lower than 6, which indicated the presence of Agave fructans that had been mono- and diacylated with lauric acid. The carbohydrate fatty acid esters (CFAE) obtained showed good emulsifying properties in W/O emulsions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Enzymatic Production of Biodiesel: Strategies to Overcome Methanol Inactivation.

PubMed

Lotti, Marina; Pleiss, Jürgen; Valero, Francisco; Ferrer, Pau

2018-05-01

Lipase-catalyzed transesterification of triglycerides and alcohols to obtain biodiesel is an environmentally friendly and sustainable route for fuels production since, besides proceeding in mild reaction conditions, it allows for the use of low-cost feedstocks that contain water and free fatty acids, for example non-edible oils and waste oils. This review article reports recent advances in the field and focus in particular on a major issue in the enzymatic process, the inactivation of most lipases caused by methanol, the preferred acyl acceptor used for alcoholysis. The recent results about immobilization of enzymes on nano-materials and the use of whole-cell biocatalysts, as well as the use of cell-surface display technologies and metabolic engineering strategies for microbial production of biodiesel are described. It is discussed also insight into the effects of methanol on lipases obtained by modeling approaches and report on studies aimed at mining novel alcohol stable enzymes or at improving robustness in existing ones by protein engineering. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Utilization of Biodiesel By-Products for Biogas Production

PubMed Central

Kolesárová, Nina; Hutňan, Miroslav; Bodík, Igor; Špalková, Viera

2011-01-01

This contribution reviews the possibility of using the by-products from biodiesel production as substrates for anaerobic digestion and production of biogas. The process of biodiesel production is predominantly carried out by catalyzed transesterification. Besides desired methylesters, this reaction provides also few other products, including crude glycerol, oil-pressed cakes, and washing water. Crude glycerol or g-phase is heavier separate liquid phase, composed mainly by glycerol. A couple of studies have demonstrated the possibility of biogas production, using g-phase as a single substrate, and it has also shown a great potential as a cosubstrate by anaerobic treatment of different types of organic waste or energy crops. Oil cakes or oil meals are solid residues obtained after oil extraction from the seeds. Another possible by-product is the washing water from raw biodiesel purification, which is an oily and soapy liquid. All of these materials have been suggested as feasible substrates for anaerobic degradation, although some issues and inhibitory factors have to be considered. PMID:21403868

In-line near-infrared (NIR) and Raman spectroscopy coupled with principal component analysis (PCA) for in situ evaluation of the transesterification reaction.

PubMed

Fontalvo-Gómez, Miriam; Colucci, José A; Velez, Natasha; Romañach, Rodolfo J

2013-10-01

Biodiesel was synthesized from different commercially available oils while in-line Raman and near-infrared (NIR) spectra were obtained simultaneously, and the spectral changes that occurred during the reaction were evaluated with principal component analysis (PCA). Raman and NIR spectra were acquired every 30 s with fiber optic probes inserted into the reaction vessel. The reaction was performed at 60-70 °C using magnetic stirring. The time of reaction was 90 min, and during this time, 180 Raman and NIR spectra were collected. NIR spectra were collected using a transflectance probe and an optical path length of 1 mm at 8 cm(-1) spectral resolution and averaging 32 scans; for Raman spectra a 3 s exposure time and three accumulations were adequate for the analysis. Raman spectroscopy showed the ester conversion as evidenced by the displacement of the C=O band from 1747 to 1744 cm(-1) and the decrease in the intensity of the 1000-1050 cm(-1) band and the 1405 cm(-1) band as methanol was consumed in the reaction. NIR spectra also showed the decrease in methanol concentration with the band in the 4750-5000 cm(-1) region; this signal is present in the spectra of the transesterification reaction but not in the neat oils. The variations in the intensity of the methanol band were a main factor in the in-line monitoring of the transesterification reaction using Raman and NIR spectroscopy. The score plot of the first principal component showed the progress of the reaction. The final product was analyzed using (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy and using mid-infrared spectroscopy, confirming the conversion of the oils to biodiesel.

Transesterification of Waste Frying Oil and Soybean Oil by Combi-lipases Under Ultrasound-Assisted Reactions.

PubMed

Poppe, Jakeline Kathiele; Matte, Carla Roberta; Fernandez-Lafuente, Roberto; Rodrigues, Rafael C; Ayub, Marco Antônio Záchia

2018-04-21

This work describes the use of an ultrasound system for the enzymatic transesterification of oils using combi-lipases as biocatalyst. The reactions were carried out evaluating the individual use of waste oil and fresh soybean oil, and the immobilized lipases CALB, TLL, and RML were used as biocatalysts. It was performed in a mixture design of three factors to obtain the ideal mixture of lipases according to the composition of fatty acids present in each oil, and the main reaction variables were optimized. After 18 h of reaction, ultrasound provided a biodiesel yield of about 90% when using soybean oil and 70% using the waste oil. The results showed that ultrasound technology, in combination with the application of enzyme mixtures, known as combi-lipases, and the use of waste oil, could be a promising route to reduce the overall process costs of enzymatic production of biodiesel.

Lipase-catalyzed biodiesel production from waste activated bleaching earth as raw material in a pilot plant.

PubMed

Park, Enoch Y; Sato, Masayasu; Kojima, Seiji

2008-05-01

The production of fatty acid methyl esters (FAMEs) from waste activated bleaching earth (ABE) discarded by the crude oil refining industry using lipase from Candida cylindracea was investigated in a 50-L pilot plant. Diesel oil or kerosene was used as an organic solvent for the transesterification of triglycerides embedded in the waste ABE. When 1% (w/w) lipase was added to waste ABE, the FAME content reached 97% (w/w) after reaction for 12 h at 25 degrees C with an agitation rate of 30 rpm. The FAME production rate was strongly dependent upon the amount of enzyme added. Mixtures of FAME and diesel oil at ratios of 45:55 (BDF-45) and 35:65 (BDF-35) were assessed and compared with the European specifications for biodiesel as automotive diesel fuel, as defined by pr EN 14214. The biodiesel quality of BDF-45 met the EN 14214 standard. BDF-45 was used as generator fuel, and the exhaust emissions were compared with those of diesel oil. The CO and SO2 contents were reduced, but nitrogen oxide emission increased by 10%. This is the first report of a pilot plant study of lipase-catalyzed FAME production using waste ABE as a raw material. This result demonstrates a promising reutilization method for the production of FAME from industrial waste resources containing vegetable oils for use as a biodiesel fuel.

Characterization of bioimprinted tannase and its kinetic and thermodynamics properties in synthesis of propyl gallate by transesterification in anhydrous medium.

PubMed

Nie, Guangjun; Zheng, Zhiming; Gong, Guohong; Zhao, Genhai; Liu, Yan; Song, Junying; Dai, Jun

2012-08-01

Tannase has been extensively applied to synthesize gallic acid esters. Bioimprinting technique can evidently enhance transesterification-catalyzing performance of tannase. In order to promote the practical utilization of the modified tannase, a few enzymatic characteristics of the enzyme and its kinetic and thermodynamics properties in synthesis of propyl gallate by transesterification in anhydrous medium have been studied. The investigations of pH and temperature found that the imprinted tannase holds an optimum activity at pH 5.0 and 40 °C. On the other hand, the bioimprinting technique has a profound enhancing effect on the adapted tannase in substrate affinity and thermostability. The kinetic and thermodynamic analyses showed that the modified tannase has a longer half-time of 1,710 h at 40 °C; the kinetic constants, the activation energy of reversible thermal inactivation, and the activation energy of irreversible thermal inactivation, respectively, are 0.054 mM, 17.35 kJ mol(-1), and 85.54 kJ mol(-1) with tannic acid as a substrate at 40 °C; the free energy of Gibbs (ΔG) and enthalpy (ΔH) were found to be 97.1 and 82.9 kJ mol(-1) separately under the same conditions.

Regioselective lipase-catalyzed synthesis of 3-o-acyl derivatives of resveratrol and study of their antioxidant properties.

PubMed

Torres, Pamela; Poveda, Ana; Jimenez-Barbero, Jesús; Ballesteros, Antonio; Plou, Francisco J

2010-01-27

One of the approaches to increasing the bioavailability of resveratrol is to protect its 3-OH phenolic group. In this work, regioselective acylation of resveratrol at 3-OH was achieved by transesterification with vinyl acetate catalyzed by immobilized lipase from Alcaligenes sp. (lipase QLG). The maximum yield of 3-O-acetylresveratrol was approximately 75%, as the lipase also catalyzes its further acetylation affording the diester 3,4'-di-O-acetylresveratrol and finally the peracetylated derivative. Long saturated and unsaturated fatty acid vinyl esters were also effective as acyl donors with similar regioselectivity. In contrast, lipase B from Candida antarctica catalyzes the acylation of the phenolic group 4'-OH with 80% yield and negligible formation of higher esters. The analysis of the antioxidant properties showed that the Trolox equivalent antioxidant capability (TEAC) values for the acetyl and stearoyl derivatives at 3-OH were, respectively, 40% and 25% referred to resveratrol. The addition of an acyl chain in the 3-OH position caused a higher loss of activity compared with that at the 4'-OH.

Mechanistic analysis of cavitation assisted transesterification on biodiesel characteristics.

PubMed

Sajjadi, Baharak; Abdul Aziz, A R; Ibrahim, Shaliza

2015-01-01

The influence of sonoluminescence transesterification on biodiesel physicochemical properties was investigated and the results were compared to those of traditional mechanical stirring. This study was conducted to identify the mechanistic features of ultrasonication by coupling statistical analysis of the experiments into the simulation of cavitation bubble. Different combinations of operational variables were employed for alkali-catalysis transesterification of palm oil. The experimental results showed that transesterification with ultrasound irradiation could change the biodiesel density by about 0.3kg/m(3); the viscosity by 0.12mm(2)/s; the pour point by about 1-2°C and the flash point by 5°C compared to the traditional method. Furthermore, 93.84% of yield with alcohol to oil molar ratio of 6:1 could be achieved through ultrasound assisted transesterification within only 20min. However, only 89.09% of reaction yield was obtained by traditional macro mixing/heating under the same condition. Based on the simulated oscillation velocity value, the cavitation phenomenon significantly contributed to generation of fine micro emulsion and was able to overcome mass transfer restriction. It was found that the sonoluminescence bubbles reached the temperature of 758-713K, pressure of 235.5-159.55bar, oscillation velocity of 3.5-6.5cm/s, and equilibrium radius of 17.9-13.7 times greater than its initial size under the ambient temperature of 50-64°C at the moment of collapse. This showed that the sonoluminescence bubbles were in the condition in which the decomposition phenomena were activated and the reaction rate was accelerated together with a change in the biodiesel properties. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluating the effectiveness of various biochars as porous media for biodiesel synthesis via pseudo-catalytic transesterification.

PubMed

Lee, Jechan; Jung, Jong-Min; Oh, Jeong-Ik; Ok, Yong Sik; Lee, Sang-Ryong; Kwon, Eilhann E

2017-05-01

This study focuses on investigating the optimized chemical composition of biochar used as porous material for biodiesel synthesis via pseudo-catalytic transesterification. To this end, six biochars from different sources were prepared and biodiesel yield obtained from pseudo-catalytic transesterification of waste cooking oil using six biochars were measured. Biodiesel yield and optimal reaction temperature for pseudo-catalytic transesterification were strongly dependent on the raw material of biochar. For example, biochar generated from maize residue exhibited the best performance, which yield was reached ∼90% at 300°C; however, the maximum biodiesel yield with pine cone biochar was 43% at 380°C. The maximum achievable yield of biodiesel was sensitive to the lignin content of biomass source of biochar but not sensitive to the cellulose and hemicellulose content. This study provides an insight for screening the most effective biochar as pseudo-catalytic porous material, thereby helping develop more sustainable and economically viable biodiesel synthesis process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Biodiesel production from wet municipal sludge: evaluation of in situ transesterification using xylene as a cosolvent.

PubMed

Choi, O K; Song, J S; Cha, D K; Lee, J W

2014-08-01

This study proposes a method to produce biodiesel from wet wastewater sludge. Xylene was used as an alternative cosolvent to hexane for transesterification in order to enhance the biodiesel yield from wet wastewater sludge. The water present in the sludge could be separated during transesterification by employing xylene, which has a higher boiling point than water. Xylene enhanced the biodiesel yield up to 8.12%, which was 2.5 times higher than hexane. It was comparable to the maximum biodiesel yield of 9.68% obtained from dried sludge. Xylene could reduce either the reaction time or methanol consumption, when compared to hexane for a similar yield. The fatty acid methyl esters (FAMEs) content of the biodiesel increased approximately two fold by changing the cosolvent from hexane to xylene. The transesterification method using xylene as a cosolvent can be applied effectively and economically for biodiesel recovery from wet wastewater sludge without drying process. Copyright © 2014 Elsevier Ltd. All rights reserved.

Technical difficulties and solutions of direct transesterification process of microbial oil for biodiesel synthesis.

PubMed

Yousuf, Abu; Khan, Maksudur Rahman; Islam, M Amirul; Wahid, Zularisam Ab; Pirozzi, Domenico

2017-01-01

Microbial oils are considered as alternative to vegetable oils or animal fats as biodiesel feedstock. Microalgae and oleaginous yeast are the main candidates of microbial oil producers' community. However, biodiesel synthesis from these sources is associated with high cost and process complexity. The traditional transesterification method includes several steps such as biomass drying, cell disruption, oil extraction and solvent recovery. Therefore, direct transesterification or in situ transesterification, which combines all the steps in a single reactor, has been suggested to make the process cost effective. Nevertheless, the process is not applicable for large-scale biodiesel production having some difficulties such as high water content of biomass that makes the reaction rate slower and hurdles of cell disruption makes the efficiency of oil extraction lower. Additionally, it requires high heating energy in the solvent extraction and recovery stage. To resolve these difficulties, this review suggests the application of antimicrobial peptides and high electric fields to foster the microbial cell wall disruption.

[Column chromatography purification and analysis of biodiesel by transesterification].

PubMed

Liu, Yang; Yi, Huai-feng; Chen, Yu; Wu, Yu-long; Yang, Ming-de; Chen, Zeng; Tong, Jun-mao

2012-02-01

In the present paper, crude biodiesel prepared with sorbifolia oil as raw material by transesterification was purified by column chromatography, then the composition of biodiesel was analyzed by gas chromatography, FTIR, GC-MS and 1H NMR. Column chromatography can separate the crude biodiesel into two fractions: petroleum ether eluted fraction (A1) and methanol eluted fraction (A2). Petroleum ether eluted fraction was mainly biodiesel fraction, which was produced from sorbifolia oil by transesterification, including methyl linoleate, methyl cis-9-octadecenoate and so on; methanol eluted fraction was mainly glycerol fraction, which came from the side reaction of transesterification. The results show that the purity of refined biodiesel increased from 77.51% to 93.872, and the product recovery rate reached up to 91.04% after the purification by column chromatography. The results obtained by FTIR and 1H NMR further showed that the column chromatography can effectively improve the purity of biodiesel. This paper provides a basis for industrialization of purification of biodiesel.

Evolution of the feruloyl esterase MtFae1a from Myceliophthora thermophila towards improved catalysts for antioxidants synthesis.

PubMed

Varriale, Simona; Cerullo, Gabriella; Antonopoulou, Io; Christakopoulos, Paul; Rova, Ulrika; Tron, Thierry; Fauré, Régis; Jütten, Peter; Piechot, Alexander; Brás, Joana L A; Fontes, Carlos M G A; Faraco, Vincenza

2018-06-01

The chemical syntheses currently employed for industrial purposes, including in the manufacture of cosmetics, present limitations such as unwanted side reactions and the need for harsh chemical reaction conditions. In order to overcome these drawbacks, novel enzymes are developed to catalyze the targeted bioconversions. In the present study, a methodology for the construction and the automated screening of evolved variants library of a Type B feruloyl esterase from Myceliophthora thermophila (MtFae1a) was developed and applied to generation of 30,000 mutants and their screening for selecting the variants with higher activity than the wild-type enzyme. The library was generated by error-prone PCR of mtfae1a cDNA and expressed in Saccharomyces cerevisiae. Screening for extracellular enzymatic activity towards 4-nitrocatechol-1-yl ferulate, a new substrate developed ad hoc for high-throughput assays of feruloyl esterases, led to the selection of 30 improved enzyme variants. The best four variants and the wild-type MtFae1a were investigated in docking experiments with hydroxycinnamic acid esters using a model of 3D structure of MtFae1a. These variants were also used as biocatalysts in transesterification reactions leading to different target products in detergentless microemulsions and showed enhanced synthetic activities, although the screening strategy had been based on improved hydrolytic activity.

Ultrasound assisted transesterification of waste cooking oil using heterogeneous solid catalyst.

PubMed

Pukale, Dipak D; Maddikeri, Ganesh L; Gogate, Parag R; Pandit, Aniruddha B; Pratap, Amit P

2015-01-01

Transesterification based biodiesel production from waste cooking oil in the presence of heterogeneous solid catalyst has been investigated in the present work. The effect of different operating parameters such as type of catalyst, catalyst concentration, oil to methanol molar ratio and the reaction temperature on the progress of the reaction was studied. Some studies related to catalyst reusability have also been performed. The important physicochemical properties of the synthesized biodiesel have also been investigated. The results showed that tri-potassium phosphate exhibits high catalytic activity for the transesterification of waste cooking oil. Under the optimal conditions, viz. catalyst concentration of 3wt% K3PO4, oil to methanol molar ratio of 1:6 and temperature of 50°C, 92.0% of biodiesel yield was obtained in 90min of reaction time. Higher yield was obtained in the presence of ultrasound as compared to conventional approach under otherwise similar conditions, which can be attributed to the cavitational effects. Kinetic studies have been carried out to determine the rate constant at different operating temperatures. It was observed that the kinetic rate constant increased with an increase in the temperature and the activation energy was found to be 64.241kJ/mol. Copyright © 2014 Elsevier B.V. All rights reserved.

Ultrasound-enhanced rapid in situ transesterification of marine macroalgae Enteromorpha compressa for biodiesel production.

PubMed

Suganya, Tamilarasan; Kasirajan, Ramachandran; Renganathan, Sahadevan

2014-03-01

In situ transesterification of Enteromorpha compressa algal biomass was carried out for the production of biodiesel. The maximum methyl esters (ME) yield of 98.89% was obtained using ultrasonic irradiation. Tetra hydro furan (THF) and acid catalyst (H2SO4) was found to be an appropriate co-solvent and catalyst for high free fatty acids (FFA) content E. compressa biomass to increase the efficiency of the reactive in situ process. The optimization study was conducted to obtain the maximum yield and it was determined as 30vol% of THF as a co-solvent, 10wt% of H2SO4, 5.5:1 ratio of methanol to algal biomass and 600rpm of mixing intensity at 65°C for 90min of ultrasonic irradiation time. The produced biodiesel was characterized by (1)H nuclear magnetic resonance spectroscopy ((1)H NMR) analysis. Kinetic studies revealed that the reaction followed the first-order reaction mechanism. Rapid in situ transesterification was found to be suitable technique to produce biodiesel from marine macroalgae feedstock. Copyright © 2014 Elsevier Ltd. All rights reserved.

Ester Cross-Link Profiling of the Cutin Polymer of Wild-Type and Cutin Synthase Tomato Mutants Highlights Different Mechanisms of Polymerization1

PubMed Central

Philippe, Glenn; Gaillard, Cédric; Petit, Johann; Geneix, Nathalie; Dalgalarrondo, Michèle; Bres, Cécile; Mauxion, Jean-Philippe; Franke, Rochus; Rothan, Christophe; Marion, Didier; Bakan, Bénédicte

2016-01-01

Cuticle function is closely related to the structure of the cutin polymer. However, the structure and formation of this hydrophobic polyester of glycerol and hydroxy/epoxy fatty acids has not been fully resolved. An apoplastic GDSL-lipase known as CUTIN SYNTHASE1 (CUS1) is required for cutin deposition in tomato (Solanum lycopersicum) fruit exocarp. In vitro, CUS1 catalyzes the self-transesterification of 2-monoacylglycerol of 9(10),16-dihydroxyhexadecanoic acid, the major tomato cutin monomer. This reaction releases glycerol and leads to the formation of oligomers with the secondary hydroxyl group remaining nonesterified. To check this mechanism in planta, a benzyl etherification of nonesterified hydroxyl groups of glycerol and hydroxy fatty acids was performed within cutin. Remarkably, in addition to a significant decrease in cutin deposition, mid-chain hydroxyl esterification of the dihydroxyhexadecanoic acid was affected in tomato RNA interference and ethyl methanesulfonate-cus1 mutants. Furthermore, in these mutants, the esterification of both sn-1,3 and sn-2 positions of glycerol was impacted, and their cutin contained a higher molar glycerol-to-dihydroxyhexadecanoic acid ratio. Therefore, in planta, CUS1 can catalyze the esterification of both primary and secondary alcohol groups of cutin monomers, and another enzymatic or nonenzymatic mechanism of polymerization may coexist with CUS1-catalyzed polymerization. This mechanism is poorly efficient with secondary alcohol groups and produces polyesters with lower molecular size. Confocal Raman imaging of benzyl etherified cutins showed that the polymerization is heterogenous at the fruit surface. Finally, by comparing tomato mutants either affected or not in cutin polymerization, we concluded that the level of cutin cross-linking had no significant impact on water permeance. PMID:26676255

Ester Cross-Link Profiling of the Cutin Polymer of Wild-Type and Cutin Synthase Tomato Mutants Highlights Different Mechanisms of Polymerization.

PubMed

Philippe, Glenn; Gaillard, Cédric; Petit, Johann; Geneix, Nathalie; Dalgalarrondo, Michèle; Bres, Cécile; Mauxion, Jean-Philippe; Franke, Rochus; Rothan, Christophe; Schreiber, Lukas; Marion, Didier; Bakan, Bénédicte

2016-02-01

Cuticle function is closely related to the structure of the cutin polymer. However, the structure and formation of this hydrophobic polyester of glycerol and hydroxy/epoxy fatty acids has not been fully resolved. An apoplastic GDSL-lipase known as CUTIN SYNTHASE1 (CUS1) is required for cutin deposition in tomato (Solanum lycopersicum) fruit exocarp. In vitro, CUS1 catalyzes the self-transesterification of 2-monoacylglycerol of 9(10),16-dihydroxyhexadecanoic acid, the major tomato cutin monomer. This reaction releases glycerol and leads to the formation of oligomers with the secondary hydroxyl group remaining nonesterified. To check this mechanism in planta, a benzyl etherification of nonesterified hydroxyl groups of glycerol and hydroxy fatty acids was performed within cutin. Remarkably, in addition to a significant decrease in cutin deposition, mid-chain hydroxyl esterification of the dihydroxyhexadecanoic acid was affected in tomato RNA interference and ethyl methanesulfonate-cus1 mutants. Furthermore, in these mutants, the esterification of both sn-1,3 and sn-2 positions of glycerol was impacted, and their cutin contained a higher molar glycerol-to-dihydroxyhexadecanoic acid ratio. Therefore, in planta, CUS1 can catalyze the esterification of both primary and secondary alcohol groups of cutin monomers, and another enzymatic or nonenzymatic mechanism of polymerization may coexist with CUS1-catalyzed polymerization. This mechanism is poorly efficient with secondary alcohol groups and produces polyesters with lower molecular size. Confocal Raman imaging of benzyl etherified cutins showed that the polymerization is heterogenous at the fruit surface. Finally, by comparing tomato mutants either affected or not in cutin polymerization, we concluded that the level of cutin cross-linking had no significant impact on water permeance. © 2016 American Society of Plant Biologists. All Rights Reserved.

Transesterification reaction for synthesis of palm-based ethylhexyl ester and formulation as base oil for synthetic drilling fluid.

PubMed

Abdul Habib, Nor Saiful Hafiz; Yunus, Robiah; Rashid, Umer; Taufiq-Yap, Yun H; Abidin, Zurina Zainal; Syam, Azhari Muhammad; Irawan, Sonny

2014-01-01

The use of vegetable oil-based ester as a base fluid in synthetic drilling fluid has become a trend in drilling operations due to its environmental advantages. The transesterification reaction of palm oil methyl ester (POME) with 2-ethylhexanol (2EH) produced 98% of palm oil-based ethylhexyl ester in less than 30 minutes. Since the transesterification reaction of POME with 2EH is a reversible reaction, its kinetics was studied in the presence of excess EH and under vacuum. The POME-to-EH molar ratio and vacuum pressure were held constant at 1:2 and 1.5 mbar respectively and the effects of temperature (70 to 110°C) were investigated. Using excess of EH and continual withdrawal of methanol via vacuum promoted the reaction to complete in less than 10 minutes. The rate constant of the reaction (k) obtained from the kinetics study was in the range of 0.44 to 0.66 s⁻¹ and the activation energy was 15.6 kJ.mol⁻¹. The preliminary investigations on the lubrication properties of drilling mud formulated with palm oil-based 2EH ester indicated that the base oil has a great potential to substitute the synthetic ester-based oil for drilling fluid. Its high kinematic viscosity provides better lubrication to the drilling fluid compared to other ester-based oils. The pour point (-15°C) and flash point (204°C) values are superior for the drilling fluid formulation. The plastic viscosity, HPHT filtrate loss and emulsion stability of the drilling fluid had given acceptable values, while gel strength and yield point could be improved by blending it with proper additives.

Etude des proprietes de surface et des proprietes rheologiques des melanges polymeres thermotropes

NASA Astrophysics Data System (ADS)

Tovar Hernandez, Maria Gabriela

We studied the surface and rheological properties of thermotropic liquid crystal polymers (TLCP) mixed with thermoplastics. We first investigated acid-base interactions in polymer component as a function of temperature, and could identified the many phase changes in TLCP. We found that acid-base interactions in TLCP decrease significantly with temperature, down to a point Tc where they become negligible. To our knowledge, it is the first time such observation is reported concerning TLCP. Acid-base interactions in the thermoplastics also vary with temperature, but they remain non-negligible, and reach a plateau at high temperature. In theory, one can obtain compatible blends between polymers A and B when their interaction parameters are both small and similar. The negligible acid-base parameter of TLCP at T > Tc should enhance the compatibility with thermoplastics. For that reason, we prepared the TLCP/thermoplastic blends at temperatures superior and inferior to Tc. We restricted our investigation to blends prepared in a Brabender Plasticorder in order to control the temperature in the mixing chamber and reduce the effects of TLCP domains deformation and reorientation. We prepared Vectra/polycarbonate blends, optimizing the drying conditions and the TLCP concentration. We optimized the drying conditions based on our previous results, finding that the transesterification reaction in presence of water happens at high temperature. Transesterification reaction was identified using infrared spectroscopy in the polymer components and in the blends. We found that this reaction occurring mainly between the ester groups in the polymer components. The product of this reaction, concentrated at the interfaces, has a remarkable effect on the blend morphology, similar to the one in compatible blend, and on its mechanical properties. To measure the effect of transesterification at the interfaces, we studied the linear viscoelasticity properties of Vectra/polycarbonate blend and their relation with their morphology. We found from the time variation of the elastic modulus at very low frequencies that the transesterification reaction was still occurring during rheological measurements. We observed coalescence of the dispersed phase droplets in all blends. Size of the droplets changed with the blend composition, the preparation temperature and the rheological characterization temperature. In addition, we compared Palierne (1990, 1991) and Lee-Park models when applied to Vectra/polycarbonate blends. We found that the Palierne model does not predict the rheological behavior of the blend, due to the mixture rule used in that model. Lee-Park model, using a different mixture rule, gives a good prediction of the linear viscoelastic properties. We succeeded in modeling the Vectra/polycarbonate rheological properties combining the characteristic relaxation times of the Palierne and Lee-Park models. Using this approach, we could clearly show that the decrease of the interfacial tension is due to the copolymer produced at the interface by transesterification reaction.

Kinetic Study on the CsXH3−X PW12O40/Fe-SiO2 Nanocatalyst for Biodiesel Production

PubMed Central

Feyzi, Mostafa; Norouzi, Leila; Rafiee, Hamid Reza

2013-01-01

The kinetic of the transesterification reaction over the CsXH3−XPW12O40/Fe-SiO2 catalyst prepared using sol-gel and impregnation procedures was investigated in different operational conditions. Experimental conditions were varied as follows: reaction temperature 323–333 K, methanol/oil molar ratio = 12/1, and the reaction time 0–240 min. The H3PW12O40 heteropolyacid has recently attracted significant attention due to its potential for application in the production of biodiesel, in either homogeneous or heterogeneous catalytic conditions. Although fatty acids esterification reaction has been known for some time, data is still scarce regarding kinetic and thermodynamic parameters, especially when catalyzed by nonconventional compounds such as H3PW12O40. Herein, a kinetic study utilizing Gc-Mas in situ allows for evaluating the effects of operation conditions on reaction rate and determining the activation energy along with thermodynamic constants including ΔG, ΔS, and ΔH. It indicated that the CsXH3−XPW12O40/Fe-SiO2 magnetic nanocatalyst can be easily recycled with a little loss by magnetic field and can maintain higher catalytic activity and higher recovery even after being used 5 times. Characterization of catalyst was carried out by using scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FT-IR), N2 adsorption-desorption measurements methods, thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC). PMID:24391465

Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

PubMed Central

2013-01-01

Background Biodiesel production has increased dramatically over the last decade, raising the need for new rapid and non-destructive analytical tools and technologies. 1H Low Field Nuclear Magnetic Resonance (LF-NMR) applications, which offer great potential to the field of biodiesel, have been developed by the Phyto Lipid Biotechnology Lab research team in the last few years. Results Supervised and un-supervised chemometric tools are suggested for screening new alternative biodiesel feedstocks according to oil content and viscosity. The tools allowed assignment into viscosity groups of biodiesel-petrodiesel samples whose viscosity is unknown, and uncovered biodiesel samples that have residues of unreacted acylglycerol and/or methanol, and poorly separated and cleaned glycerol and water. In the case of composite materials, relaxation time distribution, and cross-correlation methods were successfully applied to differentiate components. Continuous distributed methods were also applied to calculate the yield of the transesterification reaction, and thus monitor the progress of the common and in-situ transesterification reactions, offering a tool for optimization of reaction parameters. Conclusions Comprehensive applied tools are detailed for the characterization of new alternative biodiesel resources in their whole conformation, monitoring of the biodiesel transesterification reaction, and quality evaluation of the final product, using a non-invasive and non-destructive technology that is new to the biodiesel research area. A new integrated computational-experimental approach for analysis of 1H LF-NMR relaxometry data is also presented, suggesting improved solution stability and peak resolution. PMID:23590829

Transesterification of edible, non-edible and used cooking oils for biodiesel production using calcined layered double hydroxides as reusable base catalysts.

PubMed

Sankaranarayanan, Sivashunmugam; Antonyraj, Churchil A; Kannan, S

2012-04-01

Fatty acid methyl esters (FAME) were produced from edible, non-edible and used cooking oils with different fatty acid contents by transesterification with methanol using calcined layered double hydroxides (LDHs) as solid base catalysts. Among the catalysts, calcined CaAl2-LDH (hydrocalumite) showed the highest activity with >90% yield of FAME using low methanol:oil molar ratio (<6:1) at 65 °C in 5 h. The activity of the catalyst was attributed to its high basicity as supported by Hammett studies and CO(2)-TPD measurements. The catalyst was successfully reused in up to four cycles. Some of the properties such as density, viscosity, neutralization number and glycerol content of the obtained biodiesel matched well with the standard DIN values. It is concluded that a scalable heterogeneously catalyzed process for production of biodiesel in high yields from a wide variety of triglyceride oils including used oils is possible using optimized conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

In situ biodiesel production from greasy sewage sludge using acid and enzymatic catalysts.

PubMed

Sangaletti-Gerhard, Naiane; Cea, Mara; Risco, Vicky; Navia, Rodrigo

2015-03-01

This study proposes to select the most appropriate sewage sludge (greasy, primary and secondary) for in situ transesterification and to compare the technical, economic and energetic performance of an enzymatic catalyst (Novozym®435) with sulfuric acid. Greasy sludge was selected as feedstock for biodiesel production due to its high lipid content (44.4%) and low unsaponifiable matter. Maximum methyl esters yield (61%) was reached when processing the wet sludge using sulfuric acid as catalyst and n-hexane, followed by dried-greasy sludge catalyzed by Novozym®435 (57% methyl esters). Considering the economic point of view, the process using acid catalyst was more favorable compared to Novozym®435 catalyst due to the high cost of lipase. In general, greasy sludge (wet or dried) showed high potential to produce biodiesel. However, further technical adjustments are needed to make biodiesel production by in situ transesterification using acid and enzymatic catalyst feasible. Copyright © 2014 Elsevier Ltd. All rights reserved.

Production and optimization of biodiesel using mixed immobilized biocatalysts in packed bed reactor.

PubMed

Bakkiyaraj, S; Syed, Mahin Basha; Devanesan, M G; Thangavelu, Viruthagiri

2016-05-01

Vegetable oils are used as raw materials for biodiesel production using transesterification reaction. Several methods for the production of biodiesel were developed using chemical (alkali and acidic compounds) and biological catalysts (lipases). Biodiesel production catalyzed by lipases is energy and cost-saving processes and is carried out at normal temperature and pressure. The need for an efficient method for screening larger number of variables has led to the adoption of statistical experimental design. In the present study, packed bed reactor was designed to study with mixed immobilized biocatalysts to have higher productivity under optimum conditions. Contrary to the single-step acyl migration mechanism, a two-step stepwise reaction mechanism involving immobilized Candida rugosa lipase and immobilized Rhizopus oryzae cells was employed for the present work. This method was chosen because enzymatic hydrolysis followed by esterification can tolerate high free fatty acid containing oils. The effects of flow rate and bed height on biodiesel yield were studied using two factors five-level central composite design (CCD) and response surface methodology (RSM). Maximum biodiesel yield of 85 and 81 % was obtained for jatropha oil and karanja oil with the optimum bed height and optimum flow rate of 32.6 cm and 1.35 L/h, and 32.6 cm and 1.36 L/h, respectively.

Highly Productive and Enantioselective Enzyme Catalysis under Continuous Supported Liquid-Liquid Conditions Using a Hybrid Monolithic Bioreactor.

PubMed

Sandig, Bernhard; Buchmeiser, Michael R

2016-10-20

Enzyme-containing ionic liquids (ILs) were immobilized in cellulose-2.5-acetate microbeads particles embedded in a porous monolithic polyurethane matrix. This bioreactor was used under continuous liquid-liquid conditions by dissolving the substrates in a nonpolar organic phase immiscible with the ILs, thereby creating a biphasic system. Lipases (candida antarctica lipase B, CALB, candida rugosa lipase, CRL) were used to catalyze the enantioselective transesterification of racemic (R,S)-1-phenylethanol with vinyl butyrate and vinyl acetate, the esterification of (+/-)-2-isopropyl-5-methylcyclohexanol with propionic anhydride and the amidation of (R,S)-1-phenylethylamine with ethyl methoxyacetate. With this unique setup, very high productivities, that is, turnover numbers (TONs) up to 5.1×10 6 and space-time yields (STYs) up to 28 g product L -1  h -1 , exceeding the corresponding values for batch-type reactions by a factor of 3100 and 40, respectively, were achieved while maintaining or even enhancing enantioselectivity compared to batch reactions via kinetic resolution. To our best knowledge, this is the first continuously operated bioreactor using supported liquid-liquid conditions that shows these features in the synthesis of chiral esters and amides. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A green recyclable SO(3)H-carbon catalyst derived from glycerol for the production of biodiesel from FFA-containing karanja (Pongamia glabra) oil in a single step.

PubMed

Prabhavathi Devi, B L A; Vijai Kumar Reddy, T; Vijaya Lakshmi, K; Prasad, R B N

2014-02-01

Simultaneous esterification and transesterification method is employed for the preparation of biodiesel from 7.5% free fatty acid (FFA) containing karanja (Pongamia glabra) oil using water resistant and reusable carbon-based solid acid catalyst derived from glycerol in a single step. The optimum reaction parameters for obtaining biodiesel in >99% yield by simultaneous esterification and transesterification are: methanol (1:45 mole ratio of oil), catalyst 20wt.% of oil, temperature 160°C and reaction time of 4h. After the reaction, the catalyst was easily recovered by filtration and reused for five times with out any deactivation under optimized conditions. This single-step process could be a potential route for biodiesel production from high FFA containing oils by simplifying the procedure and reducing costs and effluent generation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Synthesis of CaO-CeO2 catalysts by soft template method for biodiesel production

NASA Astrophysics Data System (ADS)

Zheng, Y. C.; Yu, X. H.; Yang, J.

2017-06-01

Biodiesel has recently gained extensive attention. Catalysts play an important role in producing biodiesel by transesterification reaction. In this study, CaO-CeO2 catalysts are developed as the solid base catalyst. Using PDMS-PEO as a structure-directing agent, the prepared CaO-CeO2 catalysts have a three-dimensional interconnected porous structure, which benefits the transesterification reaction. While the added Ce slightly decreases the catalytic activity, the stability of the catalyst shows remarkable improvement. Considering the catalytic activity and stability, the best catalyst is determined to be catalyst 0.15-1073 (Ce/Ca molar ratio of 0.15 and calcination temperature of 1073 K). Under optimum reaction conditions, the biodiesel yield reaches to 97.5% and metal leaching is 117.7 ppm. For catalyst 0.15-1073 regenerated after four reaction cycles, the biodiesel yield is 94.1%. The results reveal that the CaO-CeO2 catalyst has good potential for application in large-scale biodiesel production in the future.

Behaviors of rice straw two-step liquefaction with sub/supercritical ethanol in carbon dioxide atmosphere.

PubMed

Yang, Tianhua; Wang, Jian; Li, Bingshuo; Kai, Xingping; Xing, Wanli; Li, Rundong

2018-06-01

This study extended previous work investigating two-step liquefaction by supercritical ethanol of rice straw under CO 2 atmosphere at temperatures of 270-345 °C. Subcritical CO 2 -subcritical ethanol (SubCO 2 -SubEtOH) pretreatment decreased the content of lignin in the rice stalk from 22.94 to 21.43 wt%. The results showed that although oxygen-transfer reaction, transesterification, carbonylation, and other reactions may occur with the supercritical CO 2 -supercritical ethanol (ScCO 2 -ScEtOH) liquefaction reactions, transesterification was the main reaction. The "de-oxygen-transfer" reaction mainly comprised de-oxygenation and decarboxylation. For temperatures exceeding 320 °C, the bio-oil yield decreased because the effects of esters decreased. The residence time affected the H/C and O/C ratios to a minor extent. It was shown that the nucleophilic and hydrolytic functions of ethanol might be strengthened, generating higher amounts of ester, phenolic, acidic, and hydrocarbon derivatives in the bio-oil fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization of calcium oxide catalysts from natural sources and their application in the transesterification of sunflower oil.

PubMed

Correia, Leandro Marques; Saboya, Rosana Maria Alves; Campelo, Natália de Sousa; Cecilia, Juan Antonio; Rodríguez-Castellón, Enrique; Cavalcante, Célio Loureiro; Vieira, Rodrigo Silveira

2014-01-01

The catalytic activities of calcium oxide obtained from natural sources (crab shell and eggshell) were characterized and evaluated in the transesterification of vegetable oil. These catalysts are mainly composed of calcium carbonate, which is partially converted into CaO after calcination (900°C for 2h). The catalysts have some advantages, such as abundant occurrence, low cost, porous structure, and nontoxic. The materials were characterized by XRD, FTIR, TG/DTG, CO2-TPD, XPS, SEM, and BET methods. The thermal treatment produces small particles of CaCO3 and CaO that are responsible for the catalytic activity. The conversion from triglycerides to methyl ester was not observed in transesterification carried out using natural crab shell and eggshell. Under optimized reaction conditions, the conversions to YFAME using the calcined catalysts were: crab shell (83.10±0.27 wt.%) and eggshell (97.75±0.02 wt.%). These results, showed that these materials have promising viability in transesterification for biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enhancement of biodiesel production from marine alga, Scenedesmus sp. through in situ transesterification process associated with acidic catalyst.

PubMed

Kim, Ga Vin; Choi, Woonyong; Kang, Dohyung; Lee, Shinyoung; Lee, Hyeonyong

2014-01-01

The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70 °C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp.

Enhancement of Biodiesel Production from Marine Alga, Scenedesmus sp. through In Situ Transesterification Process Associated with Acidic Catalyst

PubMed Central

Kim, Ga Vin; Choi, WoonYong; Kang, DoHyung; Lee, ShinYoung; Lee, HyeonYong

2014-01-01

The aim of this study was to increase the yield of biodiesel produced by Scenedesmus sp. through in situ transesterification by optimizing various process parameters. Based on the orthogonal matrix analysis for the acidic catalyst, the effects of the factors decreased in the order of reaction temperature (47.5%) > solvent quantity (26.7%) > reaction time (17.5%) > catalyst amount (8.3%). Based on a Taguchi analysis, the effects of the factors decreased in the order of solvent ratio (34.36%) > catalyst (28.62%) > time (19.72%) > temperature (17.32%). The overall biodiesel production appeared to be better using NaOH as an alkaline catalyst rather than using H2SO4 in an acidic process, at 55.07 ± 2.18% (based on lipid weight) versus 48.41 ± 0.21%. However, in considering the purified biodiesel, it was found that the acidic catalyst was approximately 2.5 times more efficient than the alkaline catalyst under the following optimal conditions: temperature of 70°C (level 2), reaction time of 10 hrs (level 2), catalyst amount of 5% (level 3), and biomass to solvent ratio of 1 : 15 (level 2), respectively. These results clearly demonstrated that the acidic solvent, which combined oil extraction with in situ transesterification, was an effective catalyst for the production of high-quantity, high-quality biodiesel from a Scenedesmus sp. PMID:24689039

Low-grade oils and fats: effect of several impurities on biodiesel production over sulfonic acid heterogeneous catalysts.

PubMed

Morales, Gabriel; Bautista, L Fernando; Melero, Juan A; Iglesias, Jose; Sánchez-Vázquez, Rebeca

2011-10-01

Different lipidic wastes and low-grade oils and fats have been characterized and evaluated as feedstocks for the acid-catalyzed production of FAME. The characterization of these materials has revealed significant contents of free fatty acids, Na, K, Ca, Mg, P, unsaponifiable matter and humidity. Arenesulfonic acid-functionalized SBA-15 silica catalyst has provided yields to FAME close to 80% in the simultaneous esterification-transesterification of the different feedstocks, regardless of their nature and properties, using methanol under the following reaction conditions: 160 °C, 2 h, methanol to oil molar ratio of 30, 8 wt.% catalyst loading, and 2000 rpm stirring rate. Nevertheless, reutilization of the catalyst is compromised by high levels of impurities, especially because of deactivation by strong interaction of unsaponifiable matter with the catalytic sites. The conditioning of these materials by aqueous washing in the presence of cationic-exchange resin Amberlyst-15, followed by a drying step, resulted in a lower deactivation of the catalyst. Copyright © 2011 Elsevier Ltd. All rights reserved.

Enhancement of lipase catalyzed-fatty acid methyl esters production from waste activated bleaching earth by nullification of lipase inhibitors.

PubMed

Dwiarti, Lies; Ali, Ehsan; Park, Enoch Y

2010-01-01

This study sought to identify inhibitory factors of lipase catalyzed-fatty acid methyl esters (FAME) production from waste activated bleaching earth (wABE). During the vegetable oil refinery process, activated bleaching earth (ABE) is used for removing the impure compounds, but adsorbs vegetable oil up to 35-40% as on a weight basis, and then the wABE is discarded as waste material. The impurities were extracted from the wABE with methanol and evaluated by infra-red (IR) spectroscopy, which revealed that some were chlorophyll-plant pigments. The chlorophylls inhibited the lipase during FAME conversion from wABE. The inhibition by a mixture of chlorophyll a and b was found to be competitive. The inhibition of the enzymatic hydrolysis of waste vegetable oil contained in wABE by chlorophyll a alone was competitive, while the inhibition by chlorophyll b alone was non-competitive. Furthermore, the addition of a small amount of alkali nullified this inhibitory effect and accelerated the FAME production rate. When 0.9% KOH (w/w wABE) was added to the transesterification reaction with only 0.05% lipase (w/w wABE), the maximum FAME production rate improved 120-fold, as compared to that without the addition of KOH. The alkali-combined lipase significantly enhanced the FAME production rate from wABE, in spite of the presence of the plant pigments, and even when a lower amount of lipase was used as a catalyst.

Developmentally programmed DNA deletion in Tetrahymena thermophila by a transposition-like reaction pathway.

PubMed Central

Saveliev, S V; Cox, M M

1996-01-01

We provide a molecular description of key intermediates in the deletion of two internal eliminated sequences (IES elements), the M and R regions, during macronuclear development in Tetrahymena thermophila. Using a variety of PCR-based methods in vivo, double-strand breaks are detected that are generated by hydrolytic cleavage and correspond closely to the observed chromosomal junctions left behind in the macronuclei. The breaks exhibit a temporal and structural relationship to the deletion reaction that provides strong evidence that they are intermediates in the deletion pathway. Breaks in the individual strands are staggered by 4 bp, producing a four nucleotide 5' extension. Evidence is presented that breaks do not occur simultaneously at both ends. The results are most consistent with a deletion mechanism featuring initiation by double-strand cleavage at one end of the deleted element, followed by transesterification to generate the macronuclear junction on one DNA strand. An adenosine residue is found at all the nucleophilic 3' ends used in the postulated transesterification step. Evidence for the transesterification step is provided by detection of a 3' hydroxyl that would be liberated by such a step at a deletion boundary where no other DNA strand ends are detected. Images PMID:8654384

Immobilization of Pseudomonas fluorescens lipase on hydrophobic supports and application in biodiesel synthesis by transesterification of vegetable oils in solvent-free systems.

PubMed

Lima, Lionete N; Oliveira, Gladson C; Rojas, Mayerlenis J; Castro, Heizir F; Da Rós, Patrícia C M; Mendes, Adriano A; Giordano, Raquel L C; Tardioli, Paulo W

2015-04-01

This work describes the preparation of biocatalysts for ethanolysis of soybean and babassu oils in solvent-free systems. Polystyrene, Amberlite (XAD-7HP), and octyl-silica were tested as supports for the immobilization of Pseudomonas fluorescens lipase (PFL). The use of octyl-silica resulted in a biocatalyst with high values of hydrolytic activity (650.0 ± 15.5 IU/g), immobilization yield (91.3 ± 0.3 %), and recovered activity (82.1 ± 1.5 %). PFL immobilized on octyl-silica was around 12-fold more stable than soluble PFL, at 45 °C and pH 8.0, in the presence of ethanol at 36 % (v/v). The biocatalyst provided high vegetable oil transesterification yields of around 97.5 % after 24 h of reaction using babassu oil and around 80 % after 48 h of reaction using soybean oil. The PFL-octyl-silica biocatalyst retained around 90 % of its initial activity after five cycles of transesterification of soybean oil. Octyl-silica is a promising support that can be used to immobilize PFL for subsequent application in biodiesel synthesis.

Purification of crude glycerol from transesterification reaction of palm oil using direct method and multistep method

NASA Astrophysics Data System (ADS)

Nasir, N. F.; Mirus, M. F.; Ismail, M.

2017-09-01

Crude glycerol which produced from transesterification reaction has limited usage if it does not undergo purification process. It also contains excess methanol, catalyst and soap. Conventionally, purification method of the crude glycerol involves high cost and complex processes. This study aimed to determine the effects of using different purification methods which are direct method (comprises of ion exchange and methanol removal steps) and multistep method (comprises of neutralization, filtration, ion exchange and methanol removal steps). Two crude glycerol samples were investigated; the self-produced sample through the transesterification process of palm oil and the sample obtained from biodiesel plant. Samples were analysed using Fourier Transform Infrared Spectroscopy, Gas Chromatography and High Performance Liquid Chromatography. The results of this study for both samples after purification have showed that the pure glycerol was successfully produced and fatty acid salts were eliminated. Also, the results indicated the absence of methanol in both samples after purification process. In short, the combination of 4 purification steps has contributed to a higher quality of glycerol. Multistep purification method gave a better result compared to the direct method as neutralization and filtration steps helped in removing most excess salt, fatty acid and catalyst.

Evaluation of in-situ fatty acid extraction protocols for the analysis of staphylococcal cell membrane associated fatty acids by gas chromatography.

PubMed

Crompton, Marcus J; Dunstan, R Hugh

2018-05-01

The composition and integrity of the bacterial cytoplasmic membrane is critical to the survival of staphylococci in dynamic environments and it is important to investigate how the cell membrane responds to changes in the environmental conditions. The staphylococcal membrane differs from eukaryotic and many other bacterial cell membranes by having a high abundance of branch fatty acids and relatively few unsaturated fatty acids. The range of available methods for extraction and efficient analyses of staphylococcal fatty acids was initially appraised to identify the best potential procedures for appraisal. Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213) was grown under optimal conditions to generate a cell biomass to compare the efficiencies of three approaches to extract and prepare methyl esters of the membrane fatty acids: (1) acidic direct transesterification of lipids, (2) modified basic direct transesterification of membrane lipids with adjusted reaction times and temperatures, and (3) base catalysed hydrolysis followed by acid catalysed esterification in two separate chemical reactions (MIDI process). All methods were able to extract fatty acids from the cell mass effectively where these lipids represented approximately 5% of the cellular dry mass. The acidic transesterification method had the least number of steps, the lowest coefficient of variation at 6.7% and good resistance to tolerating water. Basic transesterification was the least accurate method showing the highest coefficient of variation (26%). The MIDI method showed good recoveries, but had twice the number of steps and a coefficient of variation of 16%. It was also found that there was no need to use an anti-oxidant such as BHT for the protection of polyunsaturated fatty acids when the GC-MS injection liner was clean. It was concluded that the acidic transesterification procedures formed the most efficient and reproducible method for the analyses of staphylococcal membrane fatty acids. Crown Copyright © 2018. Published by Elsevier B.V. All rights reserved.

Biodiesel production from vegetable oil and waste animal fats in a pilot plant.

PubMed

Alptekin, Ertan; Canakci, Mustafa; Sanli, Huseyin

2014-11-01

In this study, corn oil as vegetable oil, chicken fat and fleshing oil as animal fats were used to produce methyl ester in a biodiesel pilot plant. The FFA level of the corn oil was below 1% while those of animal fats were too high to produce biodiesel via base catalyst. Therefore, it was needed to perform pretreatment reaction for the animal fats. For this aim, sulfuric acid was used as catalyst and methanol was used as alcohol in the pretreatment reactions. After reducing the FFA level of the animal fats to less than 1%, the transesterification reaction was completed with alkaline catalyst. Due to low FFA content of corn oil, it was directly subjected to transesterification. Potassium hydroxide was used as catalyst and methanol was used as alcohol for transesterification reactions. The fuel properties of methyl esters produced in the biodiesel pilot plant were characterized and compared to EN 14214 and ASTM D6751 biodiesel standards. According to the results, ester yield values of animal fat methyl esters were slightly lower than that of the corn oil methyl ester (COME). The production cost of COME was higher than those of animal fat methyl esters due to being high cost biodiesel feedstock. The fuel properties of produced methyl esters were close to each other. Especially, the sulfur content and cold flow properties of the COME were lower than those of animal fat methyl esters. The measured fuel properties of all produced methyl esters met ASTM D6751 (S500) biodiesel fuel standards. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biodiesel forming reactions using heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Liu, Yijun

Biodiesel synthesis from biomass provides a means for utilizing effectively renewable resources, a way to convert waste vegetable oils and animal fats to a useful product, a way to recycle carbon dioxide for a combustion fuel, and production of a fuel that is biodegradable, non-toxic, and has a lower emission profile than petroleum-diesel. Free fatty acid (FFA) esterification and triglyceride (TG) transesterification with low molecular weight alcohols constitute the synthetic routes to prepare biodiesel from lipid feedstocks. This project was aimed at developing a better understanding of important fundamental issues involved in heterogeneous catalyzed biodiesel forming reactions using mainly model compounds, representing part of on-going efforts to build up a rational base for assay, design, and performance optimization of solid acids/bases in biodiesel synthesis. As FFA esterification proceeds, water is continuously formed as a byproduct and affects reaction rates in a negative manner. Using sulfuric acid (as a catalyst) and acetic acid (as a model compound for FFA), the impact of increasing concentrations of water on acid catalysis was investigated. The order of the water effect on reaction rate was determined to be -0.83. Sulfuric acid lost up to 90% activity as the amount of water present increased. The nature of the negative effect of water on esterification was found to go beyond the scope of reverse hydrolysis and was associated with the diminished acid strength of sulfuric acid as a result of the preferential solvation by water molecules of its catalytic protons. The results indicate that as esterification progresses and byproduct water is produced, deactivation of a Bronsted acid catalyst like H2SO4 occurs. Using a solid composite acid (SAC-13) as an example of heterogeneous catalysts and sulfuric acid as a homogeneous reference, similar reaction inhibition by water was demonstrated for homogeneous and heterogeneous catalysis. This similarity together with other comparisons between the catalytic behaviors of liquid and solid acids suggests a common mode of operation of their Bronsted acid sites in carrying out esterification of a carboxylic acid with alcohol. The hypothesized Eley-Rideal type heterogeneous reaction mechanism involving a nucleophilic attack between adsorbed carboxylic acid and unadsorbed alcohol as the rate-limiting step was found to fit well the experimental observations and successfully predict the esterification rate obtained with SAC-13 as reaction progresses. The SAC-13 catalysis assay was also extended to carboxylic acids of higher molecular weights. A set of carboxylic acids with various alkyl chain lengths was used to investigate the structural effect of reacting carboxylic acids on heterogeneous catalyzed esterification. It was found that the reactivity of carboxylic acids was controlled by steric factors as the alkyl chain linearly lengthened. Despite their increased hydrophobicity, large carboxylic acids hardly impacted the deactivating effect of water on Bronsted acid sites. However, catalyst reusability and regeneration showed significant dependency on the size of the carboxylic acid used. With the use of larger reacting carboxylic acids, SAC-13 underwent more significant activity loss in consecutive reaction cycles due to stronger adsorption of the larger organics in the polymeric domains of the Nafion resin. In parallel to the research activity on acid catalyzed esterification, the use of strong solid bases with organic functionality (quarternary ammonium, QN+) was investigated from a fundamental perspective. Using triacetin as a model compound for TG molecules, the effectiveness of this Bronsted base functionality in transesterification was demonstrated even at mild reaction conditions. But its catalytic behavior including catalyst selectivity and deactivation was significantly affected by the nature of the adopted support. A purposive design of the immobilizing matrix is expected to optimize the activity, selectivity, and stability of the QN+ groups, thus enhancing their applicability in practical biodiesel synthesis from lipid feedstocks. As the solid organic base-matrix composite catalyst remains to be better designed to fit the need of TG methanolysis, inorganic solid bases composed of metal oxides appear to be a more feasible choice given that their thermal robustness generally allows the achievement of sufficient activity by increasing reaction temperature and potentially permits a convenient regeneration by recalcination. A study dealing with the methanolysis of real lipid feedstock (poultry fat) was carried out using Mg-Al hydrotalcite derived catalysts. From a practical standpoint, the impact of a variety of operational variables on reaction, such as catalyst pretreatments, temperature, reactants molar ratio, and usage of co-solvent were addressed. As a result, biodiesel synthesis from poultry fat was successfully conducted by appropriately adjusting these variables. However, many underlying aspects associated with catalyst performance remain unexamined and unexplained.

Integrated Energy System with Beneficial Carbon Dioxide (CO2) Use - Final Scientific/Technical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Xiaolei; Rink, Nancy T

2011-04-29

This report presents an integrated energy system that combines the production of substitute natural gas through coal hydrogasification with an algae process for beneficial carbon dioxide (CO2) use and biofuel production (funded under Department of Energy (DOE) contract DE-FE0001099). The project planned to develop, test, operate and evaluate a 2 ton-per-day coal hydrogasification plant and 25-acre algae farm at the Arizona Public Service (APS) 1000 Megawatt (MW) Cholla coal-fired power plant in Joseph City, Arizona. Conceptual design of the integrated system was undertaken with APS partners Air Liquide (AL) and Parsons. The process engineering was separated into five major areas:more » flue gas preparation and CO2 delivery, algae farming, water management, hydrogasification, and biofuel production. The process flow diagrams, energy and material balances, and preliminary major equipment needs for each major area were prepared to reflect integrated process considerations and site infrastructure design basis. The total project also included research and development on a bench-scale hydrogasifier, one-dimensional (1-D) kinetic-model simulation, extensive algae stressing, oil extraction, lipid analysis and a half-acre algae farm demonstration at APS?s Redhawk testing facility. During the project, a two-acre algae testing facility with a half-acre algae cultivation area was built at the APS Redhawk 1000 MW natural gas combined cycle power plant located 55 miles west of Phoenix. The test site integrated flue gas delivery, CO2 capture and distribution, algae cultivation, algae nursery, algae harvesting, dewatering and onsite storage as well as water treatment. The site environmental, engineering, and biological parameters for the cultivators were monitored remotely. Direct biodiesel production from biomass through an acid-catalyzed transesterification reaction and a supercritical methanol transesterification reaction were evaluated. The highest oil-to-biodiesel conversion of 79.9% was achieved with a stressed algae sample containing 40% algae oil. The effort concluded that producing biodiesel directly from the algae biomass could be an efficient, cost-effective and readily scalable way to produce biodiesel by eliminating the oil extraction process.« less

Mathematical modeling of methyl ester concentration distribution in a continuous membrane tubular reactor and comparison with conventional tubular reactor

NASA Astrophysics Data System (ADS)

Talaghat, M. R.; Jokar, S. M.; Modarres, E.

2017-10-01

The reduction of fossil fuel resources and environmental issues made researchers find alternative fuels include biodiesels. One of the most widely used methods for production of biodiesel on a commercial scale is transesterification method. In this work, the biodiesel production by a transesterification method was modeled. Sodium hydroxide was considered as a catalyst to produce biodiesel from canola oil and methanol in a continuous tubular ceramic membranes reactor. As the Biodiesel production reaction from triglycerides is an equilibrium reaction, the reaction rate constants depend on temperature and related linearly to catalyst concentration. By using the mass balance for a membrane tubular reactor and considering the variation of raw materials and products concentration with time, the set of governing equations were solved by numerical methods. The results clearly show the superiority of membrane reactor than conventional tubular reactors. Afterward, the influences of molar ratio of alcohol to oil, weight percentage of the catalyst, and residence time on the performance of biodiesel production reactor were investigated.

Transesterification reaction of the fat originated from solid waste of the leather industry.

PubMed

Işler, Asli; Sundu, Serap; Tüter, Melek; Karaosmanoğlu, Filiz

2010-12-01

The leather industry is an industry which generates a large amount of solid and liquid wastes. Most of the solid wastes originate from the pre-tanning processes while half of it comes from the fleshing step. Raw fleshing wastes which mainly consist of protein and fat have almost no recovery option and the disposal is costly. This study outlines the possibility of using the fleshing waste as an oil source for transesterification reaction. The effect of oil/alcohol molar ratio, the amount of catalyst and temperature on ester production was individually investigated and optimum reaction conditions were determined. The fuel properties of the ester product were also studied according to the EN 14214 standard. Cold filter plugging point and oxidation stability have to be improved in order to use the ester product as an alternative fuel candidate. Besides, this product can be used as a feedstock in lubricant production or cosmetic industry. Copyright © 2010 Elsevier Ltd. All rights reserved.

Selection of Lipases for the Synthesis of Biodiesel from Jatropha Oil and the Potential of Microwave Irradiation to Enhance the Reaction Rate

PubMed Central

2016-01-01

The present study deals with the enzymatic synthesis of biodiesel by transesterification of Jatropha oil (Jatropha curcas L.) with ethanol in a solvent-free system. Seven commercial lipase preparations immobilized by covalent attachment on epoxy-polysiloxane-polyvinyl alcohol composite (epoxy-SiO2-PVA) were tested as biocatalysts. Among them, immobilized lipases from Pseudomonas fluorescens (lipase AK) and Burkholderia cepacia (lipase PS) were the most active biocatalysts in biodiesel synthesis, reaching ethyl ester yields (FAEE) of 91.1 and 98.3% at 72 h of reaction, respectively. The latter biocatalyst exhibited similar performance compared to Novozym® 435. Purified biodiesel was characterized by different techniques. Transesterification reaction carried out under microwave irradiation exhibited higher yield and productivity than conventional heating. The operational stability of immobilized lipase PS was determined in repeated batch runs under conventional and microwave heating systems, revealing half-life times of 430.4 h and 23.5 h, respectively. PMID:27868060

Behavior of silica aerogel networks as highly porous solid solvent media for lipases in a model transesterification reaction.

PubMed

El Rassy, H; Perrard, A; Pierre, A C

2003-03-03

Highly porous silica aerogels with differing balances of hydrophobic and hydrophilic functionalities were studied as a new immobilization medium for enzymes. Two types of lipases from Candida rugosa and Burkholderia cepacia were homogeneously dispersed in wet gel precursors before gelation. The materials obtained were compared in a simple model reaction: transesterification of vinyl laurate by 1-octanol. To allow a better comparison of the hydrophobic/hydrophilic action of the solid, very open aerogel networks with traditional organic hydrophobic/hydrophilic liquid solvents, this reaction was studied in mixtures containing different proportions of 2-methyl-2-butanol, isooctane, and water. The results are discussed in relation to the porous and hydrophobic nature of aerogels, characterized by nitrogen adsorption. It was found that silica aerogels can be considered as "solid" solvents for the enzymes, able to provide hydrophobic/hydrophilic characteristics different from those prevailing in the liquid surrounding the aerogels. A simple mechanism of action for these aerogel networks is proposed.

Synthesis of methyl esters from waste cooking oil using construction waste material as solid base catalyst.

PubMed

Balakrishnan, K; Olutoye, M A; Hameed, B H

2013-01-01

The current research investigates synthesis of methyl esters by transesterification of waste cooking oil in a heterogeneous system, using barium meliorated construction site waste marble as solid base catalyst. The pretreated catalyst was calcined at 830 °C for 4h prior to its activity test to obtained solid oxide characterized by scanning electron microscopy/energy dispersive spectroscopy, BET surface area and pore size measurement. It was found that the as prepared catalyst has large pores which contributed to its high activity in transesterification reaction. The methyl ester yield of 88% was obtained when the methanol/oil molar ratio was 9:1, reaction temperature at 65 °C, reaction time 3h and catalyst/oil mass ratio of 3.0 wt.%. The catalyst can be reused over three cycles, offer low operating conditions, reduce energy consumption and waste generation in the production of biodiesel. Copyright © 2012 Elsevier Ltd. All rights reserved.

Data on calcium oxide and cow bone catalysts used for soybean biodiesel production.

PubMed

Ayodeji, Ayoola A; Blessing, Igho E; Sunday, Fayomi O

2018-06-01

Biodiesel was produced from soybean oil using calcium oxide and cow bone as heterogeneous catalysts, through transesterification process. The soybean oil used was characterized using gas chromatography mass spectrometer (GCMS) and the cow bone catalyst produced was characterized X-ray fluorescence (XRF) spectrometer. The effects of the variation of methanol/oil mole ratio, catalyst concentration and reaction temperature on biodiesel yield during the transesterification of soybean oil were investigated. Reaction time of 3 h and stirring rate of 500 rpm were kept constant. Using Response Optimizer (Minitab 17), the optimum conditions for biodiesel production were established. It was observed that the calcination of cow bone catalyst enhanced its conversion to apatite-CaOH. Also, the results obtained showed that the performance trends of calcined cow bone catalyst and the conventional CaO catalyst were similar.

Selection and Characterization of Biofuel-Producing Environmental Bacteria Isolated from Vegetable Oil-Rich Wastes

PubMed Central

Escobar-Niño, Almudena; Luna, Carlos; Luna, Diego; Marcos, Ana T.; Cánovas, David; Mellado, Encarnación

2014-01-01

Fossil fuels are consumed so rapidly that it is expected that the planet resources will be soon exhausted. Therefore, it is imperative to develop alternative and inexpensive new technologies to produce sustainable fuels, for example biodiesel. In addition to hydrolytic and esterification reactions, lipases are capable of performing transesterification reactions useful for the production of biodiesel. However selection of the lipases capable of performing transesterification reactions is not easy and consequently very few biodiesel producing lipases are currently available. In this work we first isolated 1,016 lipolytic microorganisms by a qualitative plate assay. In a second step, lipolytic bacteria were analyzed using a colorimetric assay to detect the transesterification activity. Thirty of the initial lipolytic strains were selected for further characterization. Phylogenetic analysis revealed that 23 of the bacterial isolates were Gram negative and 7 were Gram positive, belonging to different clades. Biofuel production was analyzed and quantified by gas chromatography and revealed that 5 of the isolates produced biofuel with yields higher than 80% at benchtop scale. Chemical and viscosity analysis of the produced biofuel revealed that it differed from biodiesel. This bacterial-derived biofuel does not require any further downstream processing and it can be used directly in engines. The freeze-dried bacterial culture supernatants could be used at least five times for biofuel production without diminishing their activity. Therefore, these 5 isolates represent excellent candidates for testing biofuel production at industrial scale. PMID:25099150

Synthesis of Transesterified Palm Olein-Based Polyol and Rigid Polyurethanes from this Polyol.

PubMed

Arniza, Mohd Zan; Hoong, Seng Soi; Idris, Zainab; Yeong, Shoot Kian; Hassan, Hazimah Abu; Din, Ahmad Kushairi; Choo, Yuen May

Transesterification of palm olein with glycerol can increase the functionality by introducing additional hydroxyl groups to the triglyceride structure, an advantage compared to using palm olein directly as feedstock for producing palm-based polyol. The objective of this study was to synthesize transesterified palm olein-based polyol via a three-step reaction: (1) transesterification of palm olein, (2) epoxidation and (3) epoxide ring opening. Transesterification of palm olein yielded approximately 78 % monoglyceride and has an hydroxyl value of approximately 164 mg KOH g -1 . The effect of formic acid and hydrogen peroxide concentrations on the epoxidation reaction was studied. The relationships between epoxide ring-opening reaction time and residual oxirane oxygen content and hydroxyl value were monitored. The synthesized transesterified palm olein-based polyol has hydroxyl value between 300 and 330 mg KOH g -1 and average molecular weight between 1,000 and 1,100 Da. On the basis of the hydroxyl value and average molecular weight of the polyol, the transesterified palm olein-based polyol is suitable for producing rigid polyurethane foam, which can be designed to exhibit desirable properties. Rigid polyurethane foams were synthesized by substituting a portion of petroleum-based polyol with the transesterified palm olein-based polyol. It was observed that by increasing the amount of transesterified palm olein-based polyol, the core density and compressive strength were reduced but at the same time the insulation properties of the rigid polyurethane foam were improved.

Application of kaolin-based catalysts in biodiesel production via transesterification of vegetable oils in excess methanol.

PubMed

Dang, Tan Hiep; Chen, Bing-Hung; Lee, Duu-Jong

2013-10-01

Biodiesel production from transesterification of vegetable oils in excess methanol was performed by using as-prepared catalyst from low-cost kaolin clay. This effective heterogeneous catalyst was successfully prepared from natural kaolin firstly by dehydroxylation at 800°C for 10h and, subsequently, by NaOH-activation hydrothermally at 90°C for 24h and calcined again at 500°C for 6h. The as-obtained catalytic material was characterized with instruments, including FT-IR, XRD, SEM, and porosimeter (BET/BJH analysis). The as-prepared catalyst was advantageous not only for its easy preparation, but also for its cost-efficiency and superior catalysis in transesterification of vegetable oils in excess methanol to produce fatty acid methyl esters (FAMEs). Conversion efficiencies of soybean and palm oils to biodiesel over the as-prepared catalysts reached 97.0±3.0% and 95.4±3.7%, respectively, under optimal conditions. Activation energies of transesterification reactions of soybean and palm oils in excess methanol using these catalysts are 14.09 kJ/mol and 48.87 kJ/mol, respectively. Copyright © 2012 Elsevier Ltd. All rights reserved.

Full-scale treatment of wastewater from a biodiesel fuel production plant with alkali-catalyzed transesterification.

PubMed

De Gisi, Sabino; Galasso, Maurizio; De Feo, Giovanni

2013-01-01

The treatment of wastewater derived from a biodiesel fuel (BDF) production plant with alkali-catalyzed transesterification was studied at full scale. The investigated wastewater treatment plant consisted of the following phases: primary adsorption/coagulation/flocculation/sedimentation processes, biological treatment with the combination of trickling filter and activated sludge systems, secondary flocculation/sedimentation processes, and reverse osmosis (RO) system with spiral membranes. All the processes were developed in a continuous mode, while the RO experiment was performed with batch tests. Two types of BDF wastewater were considered: the first wastewater (WW1) had an average total chemical oxygen demand (COD), pH and feed flow rate of 10,850.8 mg/L, 5.9 and 2946.7 L/h, respectively, while the second wastewater (WW2) had an average total COD, pH and feed flow rate of 43,898.9 mg/L, 3.3 and 2884.6 L/h, respectively. The obtained results from the continuous tests showed a COD removal percentage of more than 90% for the two types of wastewater considered. The removal of biorefractory COD and salts was obtained with a membrane technology in order to reuse the RO permeate in the factory production cycle. The rejections percentage of soluble COD, chlorides and sulphates were 92.8%, 95.0% and 99.5%, respectively. Because the spiral membranes required a high number of washing cycles, the use of plane membranes was preferable. Finally, the RO reject material should be evaporated using the large amount of inexpensive heat present in this type of industry.

Ethanesulfonic acid-based esterification of industrial acidic crude palm oil for biodiesel production.

PubMed

Hayyan, Adeeb; Mjalli, Farouq S; Hashim, Mohd Ali; Hayyan, Maan; AlNashef, Inas M; Al-Zahrani, Saeed M; Al-Saadi, Mohammed A

2011-10-01

An industrial grade acidic crude palm oil (ACPO) pre-treatment process was carried out using ethanesulfonic acid (ESA) as a catalyst in the esterification reaction. ESA was used in different dosages to reduce free fatty acid (FFA) to a minimum level for the second stage of biodiesel production via alkaline transesterification reaction. Different process operating conditions were optimized such as ESA dosage (0.25-3.5% wt/wt), methanol to ACPO molar ratio (1:1-20:1), reaction temperature (40-70 °C), and reaction time (3-150 min). This study revealed the potential use of abundant quantities of ACPO from oil palm mills for biodiesel production. The lab scale results showed the effectiveness of the pre-treatment process using ESA catalyst. Three consecutive catalyst recycling runs were achieved without significant degradation in its performance. Second and third reuse runs needed more reaction time to achieve the target level of FFA content. Esterification and transesterification using ESA and KOH respectively is proposed for biodiesel industrial scale production. The produced biodiesel meets the international standards specifications for biodiesel fuel (EN 14214 and ASTM D6751). Copyright © 2011 Elsevier Ltd. All rights reserved.

Implication of substrate-assisted catalysis on improving lipase activity or enantioselectivity in organic solvents.

PubMed

Tsai, Shau-Wei; Chen, Chun-Chi; Yang, Hung-Shien; Ng, I-Son; Chen, Teh-Liang

2006-08-01

In comparison with the biocatalyst engineering and medium engineering approaches, very few examples have been reported on using the substrate engineering approach such as substrate-assisted catalysis (SAC) for naturally occurring or engineered lipases and serine proteases to improve the enzyme activity and enantioselectivity. By employing lipase-catalyzed hydrolysis of (R,S)-naproxen esters in water-saturated isooctane as the model system, we demonstrate the proton shuttle device to the leaving alcohol of the substrate as a new means of SAC to effectively improve the lipase activity or enantioselectivity. The result cannot only provide a strong evidence for the rate-limiting proton transfer for the bond-breaking of tetrahedron intermediate of the acylation step, but also sheds light for performing the hydrolysis, transesterification or aminolysis in organic solvents for the ester substrate that originally lipases cannot catalyze, but now can after introducing the device.

Process development for scum to biodiesel conversion.

PubMed

Bi, Chong-hao; Min, Min; Nie, Yong; Xie, Qing-long; Lu, Qian; Deng, Xiang-yuan; Anderson, Erik; Li, Dong; Chen, Paul; Ruan, Roger

2015-06-01

A novel process was developed for converting scum, a waste material from wastewater treatment facilities, to biodiesel. Scum is an oily waste that was skimmed from the surface of primary and secondary settling tanks in wastewater treatment plants. Currently scum is treated either by anaerobic digestion or landfilling which raised several environmental issues. The newly developed process used a six-step method to convert scum to biodiesel, a higher value product. A combination of acid washing and acid catalyzed esterification was developed to remove soap and impurities while converting free fatty acids to methyl esters. A glycerol washing was used to facilitate the separation of biodiesel and glycerin after base catalyzed transesterification. As a result, 70% of dried and filtered scum was converted to biodiesel which is equivalent to about 134,000 gallon biodiesel per year for the Saint Paul waste water treatment plant in Minnesota. Copyright © 2015 Elsevier Ltd. All rights reserved.

Comparative assessment of various lipid extraction protocols and optimization of transesterification process for microalgal biodiesel production.

PubMed

Mandal, Shovon; Patnaik, Reeza; Singh, Amit Kumar; Mallick, Nirupama

2013-01-01

Biodiesel, using microalgae as feedstocks, is being explored as the most potent form of alternative diesel fuel for sustainable economic development. A comparative assessment of various protocols for microalgal lipid extraction was carried out using five green algae, six blue-green algae and two diatom species treated with different single and binary solvents both at room temperature and using a soxhlet. Lipid recovery was maximum with chloroform-methanol in the soxhlet extractor. Pretreatments ofbiomass, such as sonication, homogenization, bead-beating, lyophilization, autoclaving, microwave treatment and osmotic shock did not register any significant rise in lipid recovery. As lipid recovery using chloroform-methanol at room temperature demonstrated a marginally lower value than that obtained under the soxhlet extractor, on economical point of view, the former is recommended for microalgal total lipid extraction. Transesterification process enhances the quality of biodiesel. Experiments were designed to determine the effects of catalyst type and quantity, methanol to oil ratio, reaction temperature and time on the transesterification process using response surface methodology. Fatty acid methyl ester yield reached up to 91% with methanol:HCl:oil molar ratio of 82:4:1 at 65 degrees C for 6.4h reaction time. The biodiesel yield relative to the weight of the oil was found to be 69%.

Synthesis of methyl ester sulfonate surfactant from crude palm oil as an active substance of laundry liquid detergent

NASA Astrophysics Data System (ADS)

Slamet, Ibadurrohman, Muhammad; Wulandari, Pangiastika Putri

2017-11-01

Liquid detergent with combination of MES surfactant and TiO2 nanoparticles to remove and degrade the dirt in the form of methylene blue and produce waste with the lowest surfactant residual concentration has been done. The formation of MES is carried out by esterification and transesterification of crude palm oil, sulfonation, refining, and neutralization. The photocatalyst TiO2 nanoparticles is added as an additive to improve surfactant performance in removing dirt and degrading organic compounds. MES formation is performed by varying the mole ratio of the reactants in the esterification and transesterification reactions, and the mole ratios between methyl esters and NaHSO3 during the sulfonation reaction. Variations of MES surfactant and TiO2 nanoparticles compositions were performed to obtain detergent stability. Data analysis technique in this research is characterization of methyl ester, MES surfactant, and detergent using UV-Vis spectrophotometer instrument, FTIR, GC-MS, and LC-MS. The optimum conditions in the esterification and transesterification process were each mole ratio of 1: 6 between CPO and methanol based on the highest conversion, 99%. The optimum condition of the sulfonation process is the 1: 1.5 mole ratio between methyl ester and NaHSO3 based on the lowest surface tension value, which is about 36 dyne/cm.

Kinetic studies and thermodynamics of oil extraction and transesterification of Chlorella sp. for biodiesel production.

PubMed

Ahmad, A L; Yasin, N H Mat; Derek, C J C; Lim, J K

2014-01-01

In this work, a mixture of chloroform and methanol (1:1, v/v) was applied to oil extraction from Chlorella sp. at 30, 40, 50 and 60 degrees C for 150 min extraction times. Kinetic studies revealed that the values of n and the rate constants were found to depend strongly on temperature. The activation energy was Ea = 38.893 kJ/mol, and the activation thermodynamic parameters at 60 degrees C were ΔS≠ = -180.190 J/mol , ΔH≠ = 36.124k J/mol and ΔG≠ = 96.128k J/mol. Both ΔH and ΔS yielded positive values, whereas ΔG was negative at 60 degrees C, indicating that this process is endothermic, irreversible and spontaneous. The acidic transesterification process was also investigated by gas chromatographic analysis of the microalgae fatty acid methyl esters (biodiesel) at different temperatures and reaction times. The fatty acid profile indicated that the main components were palmitic, linoleic and linolenic acids. The concentration of linolenic acid increased and oleic acid decreased as the temperature increased. Two-hour transesterification is the best reaction time for biodiesel production because it produces the highest percentage of unsaturated fatty acids (74%). These results indicate the potential of Chlorella sp. to produce biodiesel of good quality.

Synthesis of decacationic [60]fullerene decaiodides giving photoinduced production of superoxide radicals and effective PDT-mediation on antimicrobial photoinactivation

PubMed Central

Wang, Min; Maragani, Satyanarayana; Huang, Liyi; Jeon, Seaho; Canteenwala, Taizoon; Hamblin, Michael R.; Chiang, Long Y.

2013-01-01

We report a novel class of highly water-soluble decacationic methano[60]fullerene decaiodides C60[>M(C3N6+C3)2]-(I−)10[1-(I−)10] capable of co-producing singlet oxygen (Type-II) and highly reactive hydroxyl radicals, formed from superoxide radicals in Type-I photosensitizing reactions, upon illumination at both UVA and white light wavelengths. The O2-·-production efficiency of 1-(I−)10 was confirmed by using an O2-·-reactive bis(2,4-dinitrobenzenesulfonyl)tetrafluorofluorescein probe and correlated to the photoinduced electron-transfer event going from iodide anions to C360∗[>M(C3N6+C3)2] leading to C60-·[>M(C3N6+C3)2]. Incorporation of a defined number (ten) of quaternary ammonium cationic charges per C60 in 1 was aimed to enhance its ability to target pathogenic Gram-positive and Gram-negative bacterial cells. We used the well-characterized malonato[60]fullerene diester mono-adduct C60[>M(t-Bu)2] as the starting fullerene derivative to provide a better synthetic route to C60[>M(C3N6+C3)2] via transesterification reaction under trifluoroacetic acid catalyzed conditions. These compounds may be used as effective photosensitizers and nano-PDT drugs for photoinactivation of pathogens. PMID:23474903

Thermodynamics of Enzyme-Catalyzed Reactions Database

National Institute of Standards and Technology Data Gateway

SRD 74 Thermodynamics of Enzyme-Catalyzed Reactions Database (Web, free access)   The Thermodynamics of Enzyme-Catalyzed Reactions Database contains thermodynamic data on enzyme-catalyzed reactions that have been recently published in the Journal of Physical and Chemical Reference Data (JPCRD). For each reaction the following information is provided: the reference for the data, the reaction studied, the name of the enzyme used and its Enzyme Commission number, the method of measurement, the data and an evaluation thereof.

Enzymatic synthesis of structured lipids.

PubMed

Iwasaki, Yugo; Yamane, Tsuneo

2004-01-01

Structured lipids (SLs) are defined as lipids that are modified chemically or enzymatically in order to change their structure. This review deals with structured triacylglycerols (STGs) and structured phospholipids (SPLs). The most typical STGs are MLM-type STGs, having medium chain fatty acids (FAs) at the 1- and 3-positions and a long chain fatty acid at the 2- position. MLM-type STGs are synthesized by: 1) 1,3-position-specific lipase-catalyzed acyl exchange of TG with FA or with FA ethylester (FAEt); 2) 1,3-position-specific lipase-catalyzed acylation of glycerol with FA, giving symmetric 1,3-diacyl-sn-glycerol, followed by chemical acylation at the sn-2 position, and; 3) 1,3-position-specific lipase-catalyzed deacylation of TG, giving 2-monoacylglycerol, followed by reacylation at the 1- and 3-positions with FA or with (FAEt). Enzymatic preparation of SPLs requires: 1) acyl group modification, and 2) head group modification of phospholipids. Acyl group modification is performed using lipases or phospholipase A2-mediated transesterification or ester synthesis to introduce arbitrary fatty acid to phospholipids. Head group modification is carried out by phospholipase D-catalyzed transphosphatidylation. A wide range of compounds can be introduced into the polar head of phospholipids, making it possible to prepare various SPLs.

Study on production of biodiesel from Jatropha oil and the performance and emission of a diesel engine

NASA Astrophysics Data System (ADS)

Nor, N. F. M.; Hafidzal, M. H. M.; Shamsuddin, S. A.; Ismail, M. S.; Hashim, A. H.

2015-05-01

The use of nonedible oil as a feedstock is needed to replace edible oil as an alternative fuel for diesel engine. This nonedible oils in diesel engine however leads to low performance and higher emission due to its high viscosity. The characteristics of the fuel can be improved through transesterification process. The yield of biodiesel from Jatropha oil using potassium hydroxide catalyst concentration of 1%, reaction temperature 60°C, reaction time 40 minutes and molar ratio methanol to oil 6:1 was 70.1% from the lab scale. The experimental study on the performances and emissions of a diesel engine is carried out using the Jatropha biodiesel produced from the transesterification process and compared with pure diesel. Results show that B20 has closer performance to diesel and lower emission compared to B5 and diesel in terms of CO2 and HC.

Trimethylsulfonium hydroxide as derivatization reagent for the chemical investigation of drying oils in works of art by gas chromatography.

PubMed

Dron, Julien; Linke, Robert; Rosenberg, Erwin; Schreiner, Manfred

2004-08-20

A procedure for the determination of fatty acids (FA) and glycerol in oils has been developed. The method includes a derivatization step of the FAs into their methyl esters or a transesterification of the triacylglycerols with trimethylsulfonium hydroxide (TMSH), respectively. The analysis is carried out by gas chromatography with parallel flame ionization and mass spectrometric detection. The parameters involved in the transesterification reaction were optimized. Only the stoichiometric ratio of TMSH:total FA amount showed a significant influence on the reaction yield. Relative standard deviations for 10 replicates were below 3% for all FAs studied and their linearity range was 0.5-50 mmol/L, when using heptadecanoic acid as an internal standard. The final procedure was rapid and required little sample handling. It was then tested on fresh oil samples and presented satisfying results, in agreement with previous works.

Functional Characterization of a Novel Marine Microbial GDSL Lipase and Its Utilization in the Resolution of (±)-1-Phenylethanol.

PubMed

Deng, Dun; Zhang, Yun; Sun, Aijun; Liang, Jiayuan; Hu, Yunfeng

2016-04-01

A novel GDSL lipase (MT6) was cloned from the genome of Marinactinospora thermotolerans SCSIO 00652 identified from the South China Sea. MT6 showed its maximum identity of 59 % with a putative lipase from Nocardiopsis dassonville. MT6 was heterologously expressed in E. coli BL21(DE3) and further functionally characterized. MT6 could efficiently resolve racemic 1-phenylethanol and generate (R)-1-phenylethanol with high enantiomeric excess (99 %) and conversion rate (54 %) through transesterification reactions after process optimization. Our report was the first one report about the utilization of one GDSL lipase in the preparation of chiral chemicals by transesterification reactions, and the optical selectivity of MT6 was interestingly opposite to those of other common lipases. GDSL lipases represented by MT6 possess great potential for the generation of valuable chiral chemicals in industry.

Production of Biodiesel from Thespesiapopulnea seed oil through rapid in situ transesterification - an optimization study and assay of fuel properties

NASA Astrophysics Data System (ADS)

Bhargavi, G.; Nageswara Rao, P.; Renganathan, S.

2018-03-01

Biodiesel production was carried out from Thespesia populnea seed oil through rapid insitu transesterification. Influence of reaction parameters such as catalyst type and concentration, methanol to biomass ratio, co-solvent volume, temperature and agitation speed on conversion of oil into methyl esters was investigated. The effect of different co-solvents on conversion was evaluated. Optimum methyl ester conversion of 97.80% was achieved at 1.5wt% of KOH catalyst, 5.5:1 (v/w) methanol to biomass ratio, 25vol%tetrahydrofuranco-solvent, 60°C and 500 rpm within 120min of reaction time. Fuel properties of produced methyl esters were well fitted within the limits of ASTMD 6751 standards. Considering the properties of produced biodiesel, Thespesia populnea seed derived biodiesel can be used as potential alternate to fossil diesel fuel.

Production of biodiesel by enzymatic transesterification of waste sardine oil and evaluation of its engine performance.

PubMed

Arumugam, A; Ponnusami, V

2017-12-01

Waste sardine oil, a byproduct of fish industry, was employed as a low cost feedstock for biodiesel production. It has relatively high free fatty acid (FFA) content (32 mg KOH/g of oil). Lipase enzyme immobilized on activated carbon was used as the catalyst for the transesterification reaction. Process variables viz. reaction temperature, water content and oil to methanol molar ratio were optimized. Optimum methanol to oil molar ratio, water content and temperature were found to be 9:1, 10 v/v% and 30 °C respectively. Reusability of immobilized lipase was studied and it was found after 5 cycles of reuse there was about 13% drop in FAME yield. Engine performance of the produced biodiesel was studied in a Variable Compression Engine and the results confirm that waste sardine oil is a potential alternate and low-cost feedstock for biodiesel production.

Ultrasonic-assisted continuous methanolysis of Jatropha curcas oil in the appearance of biodiesel used as an intermediate solvent.

PubMed

Kumar, Gajendra; Singh, Vidhi; Kumar, Dharmendra

2017-11-01

A environmental friendly system for fast transesterification of Jatropha curcas oil was developed for the production of biodiesel using an ultrasonic-assisted continuous tank reactor in the presence of fatty acid methyl ester (FAMEs) used as a green (intermediate) solvent with potassium hydroxide used as a catalyst. This research provide a new biodiesel production process, the optimal condition for the reaction were established: reaction temperature 25°C oil to methanol molar ratio was 1:5, catalyst concentration 0.75wt% of oil, solvent concentration 7.5%, flow rate 241.68±0.80ml/min, ultrasonic amplitude 60% and ultrasonic cycles 0.7s, transesterification was completed within 1.09min (residence time). The purity and conversion of biodiesel was 98.75±0.50% analyzed by the reverse phase HPLC method. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemoselective catalytic conversion of glycerol as a biorenewable source to valuable commodity chemicals.

PubMed

Zhou, Chun-Hui Clayton; Beltramini, Jorge N; Fan, Yong-Xian; Lu, G Q Max

2008-03-01

New opportunities for the conversion of glycerol into value-added chemicals have emerged in recent years as a result of glycerol's unique structure, properties, bioavailability, and renewability. Glycerol is currently produced in large amounts during the transesterification of fatty acids into biodiesel and as such represents a useful by-product. This paper provides a comprehensive review and critical analysis on the different reaction pathways for catalytic conversion of glycerol into commodity chemicals, including selective oxidation, selective hydrogenolysis, selective dehydration, pyrolysis and gasification, steam reforming, thermal reduction into syngas, selective transesterification, selective etherification, oligomerization and polymerization, and conversion of glycerol into glycerol carbonate.

Magnesium oxide prepared via metal-chitosan complexation method: Application as catalyst for transesterification of soybean oil and catalyst deactivation studies

NASA Astrophysics Data System (ADS)

Almerindo, Gizelle I.; Probst, Luiz F. D.; Campos, Carlos E. M.; de Almeida, Rusiene M.; Meneghetti, Simoni M. P.; Meneghetti, Mario R.; Clacens, Jean-Marc; Fajardo, Humberto V.

2011-10-01

A simple method to prepare magnesium oxide catalysts for biodiesel production by transesterification reaction of soybean oil with ethanol is proposed. The method was developed using a metal-chitosan complex. Compared to the commercial oxide, the proposed catalysts displayed higher surface area and basicity values, leading to higher yield in terms of fatty acid ethyl esters (biodiesel). The deactivation of the catalyst due to contact with CO2 and H2O present in the ambient air was verified. It was confirmed that the active catalytic site is a hydrogenocarbonate adsorption site.

Lipase immobilization for catalytic applications obtained using fumed silica deposited with MAPLE technique

NASA Astrophysics Data System (ADS)

Bloisi, Francesco; Califano, Valeria; Perretta, Giuseppe; Nasti, Libera; Aronne, Antonio; Di Girolamo, Rocco; Auriemma, Finizia; De Rosa, Claudio; Vicari, Luciano R. M.

2016-06-01

Lipases are enzymes used for catalyzing reactions of acylglycerides in biodiesel production from lipids, where enzyme immobilization on a substrate is required. Silica nanoparticles in different morphologies and configurations are currently used in conjunction with biological molecules for drug delivery and catalysis applications, but up to date their use for triglycerides has been limited by the large size of long-chain lipid molecules. Matrix assisted pulsed laser evaporation (MAPLE), a laser deposition technique using a frozen solution/suspension as a target, is widely used for deposition of biomaterials and other delicate molecules. We have carried out a MAPLE deposition starting from a frozen mixture containing fumed silica and lipase in water. Deposition parameters were chosen in order to increase surface roughness and to promote the formation of complex structures. Both the target (a frozen thickened mixture of nanoparticles/catalyst in water) and the deposition configuration (a small target to substrate distance) are unusual and have been adopted in order to increase surface contact of catalyst and to facilitate access to long-chain molecules. The resulting innovative film morphology (fumed silica/lipase cluster level aggregation) and the lipase functionality (for catalytic biodiesel production) have been studied by FESEM, FTIR and transesterification tests.

Optimization of experimental conditions for composite biodiesel production from transesterification of mixed oils of Jatropha and Pongamia

NASA Astrophysics Data System (ADS)

Yogish, H.; Chandrashekara, K.; Pramod Kumar, M. R.

2012-11-01

India is looking at the renewable alternative sources of energy to reduce its dependence on import of crude oil. As India imports 70 % of the crude oil, the country has been greatly affected by increasing cost and uncertainty. Biodiesel fuel derived by the two step acid transesterification of mixed non-edible oils from Jatropha curcas and Pongamia (karanja) can meet the requirements of diesel fuel in the coming years. In the present study, different proportions of Methanol, Sodium hydroxide, variation of Reaction time, Sulfuric acid and Reaction Temperature were adopted in order to optimize the experimental conditions for maximum biodiesel yield. The preliminary studies revealed that biodiesel yield varied widely in the range of 75-95 % using the laboratory scale reactor. The average yield of 95 % was obtained. The fuel and chemical properties of biodiesel, namely kinematic viscosity, specific gravity, density, flash point, fire point, calorific value, pH, acid value, iodine value, sulfur content, water content, glycerin content and sulfated ash values were found to be within the limits suggested by Bureau of Indian Standards (BIS 15607: 2005). The optimum combination of Methanol, Sodium hydroxide, Sulfuric acid, Reaction Time and Reaction Temperature are established.

Transesterification of PHA to oligomers covalently bonded with (bio)active compounds containing either carboxyl or hydroxyl functionalities.

PubMed

Kwiecień, Iwona; Radecka, Iza; Kowalczuk, Marek; Adamus, Grażyna

2015-01-01

This manuscript presents the synthesis and structural characterisation of novel biodegradable polymeric controlled-release systems of pesticides with potentially higher resistance to weather conditions in comparison to conventional forms of pesticides. Two methods for the preparation of pesticide-oligomer conjugates using the transesterification reaction were developed. The first method of obtaining conjugates, which consist of bioactive compounds with the carboxyl group and polyhydroxyalkanoates (PHAs) oligomers, is "one-pot" transesterification. In the second method, conjugates of bioactive compounds with hydroxyl group and polyhydroxyalkanoates oligomers were obtained in two-step method, through cyclic poly(3-hydroxybutyrate) oligomers. The obtained pesticide-PHA conjugates were comprehensively characterised using GPC, 1H NMR and mass spectrometry techniques. The structural characterisation of the obtained products at the molecular level with the aid of mass spectrometry confirmed that both of the synthetic strategies employed led to the formation of conjugates in which selected pesticides were covalently bonded to PHA oligomers via a hydrolysable ester bond.

Transesterification of waste cooking oil by an organic solvent-tolerant alkaline lipase from Streptomyces sp. CS273.

PubMed

Mander, Poonam; Yoo, Hah-Young; Kim, Seung Wook; Choi, Yun Hee; Cho, Seung Sik; Yoo, Jin Cheol

2014-02-01

The aim of this present study was to produce a microbial enzyme that can potentially be utilized for the enzymatic transesterification of waste cooking oil. To that end, an extracellular lipase was isolated and purified from the culture broth of Streptomyces sp. CS273. The molecular mass of purified lipase was estimated to be 36.55 kDa by SDS PAGE. The optimum lipolytic activity was obtained at alkaline pH 8.0 to 8.5 and temperature 40 °C, while the enzyme was stable in the pH range 7.0 ∼ 9.0 and at temperature ≤40 °C. The lipase showed highest hydrolytic activity towards p-nitrophenyl myristate (C14). The lipase activity was enhanced by several salts and detergents including NaCl, MnSo₄, and deoxy cholic acid, while phenylmethylsulfonyl fluoride at concentration 10 mM inhibited the activity. The lipase showed tolerance towards different organic solvents including ethanol and methanol which are commonly used in transesterification reactions to displace alcohol from triglycerides (ester) contained in renewable resources to yield fatty acid alkyl esters known as biodiesel. Applicability of the lipase in transesterification of waste cooking oil was confirmed by gas chromatography mass spectrometry analysis.

Ohmic heating pretreatment of algal slurry for production of biodiesel.

PubMed

Yodsuwan, Natthawut; Kamonpatana, Pitiya; Chisti, Yusuf; Sirisansaneeyakul, Sarote

2018-02-10

Suspensions of the model microalga Chlorella sp. TISTR 8990 were pretreated by ohmic heating to facilitate release of lipids from the cells in subsequent extraction and lipase-mediated transesterification to biodiesel. After ohmic pretreatment, the moist biomass was suspended in a system of water, hexane, methanol and immobilized lipase for extraction of lipids and simultaneous conversion to biodiesel. The ohmic pretreatment was optimized using an experimental design based on Taguchi method to provide treated biomass that maximized the biodiesel yield in subsequent extraction-transesterification operation. The experimental factors were the frequency of electric current (5-10 5  Hz), the processing temperature (50-70 °C), the algal biomass concentration in the slurry (algal fresh weight to water mass ratio of 1-3) and the incubation time (1-3 min). Extraction-transesterification of the pretreated biomass was carried out at 40 °C for 24 h using a reaction systems of a fixed composition (i.e. biomass, hexane, methanol, water and immobilized enzyme). Compared to control (i.e. untreated biomass), the ohmic pretreatment under optimal conditions (5 Hz current frequency, 70 °C, 1:2 mass ratio of biomass to water, incubation time of 2-min) increased the rate of subsequent transesterification by nearly 2-fold. Copyright © 2017 Elsevier B.V. All rights reserved.

Biodiesel Fuel Quality and the ASTM Biodiesel Standard

USDA-ARS?s Scientific Manuscript database

Biodiesel is usually produced from vegetable oils, animal fats and used cooking oils with alternative feedstocks such as algae receiving increasing interest. The transesterification reaction which produces biodiesel also produces glycerol and proceeds stepwise via mono- and diacylglycerol intermedi...

Biodiesel Fuel Quality and the ASTM Standard

USDA-ARS?s Scientific Manuscript database

Biodiesel is usually produced from vegetable oils, animal fats and used cooking oils with alternative feedstocks such as algae receiving increasing interest. The transesterification reaction which produces biodiesel also produces glycerol and proceeds stepwise via mono- and diacylglycerol intermedia...

The Production of Biodiesel and Bio-kerosene from Coconut Oil Using Microwave Assisted Reaction

NASA Astrophysics Data System (ADS)

SAIFUDDIN, N.; SITI FAZLILI, A.; KUMARAN, P.; PEI-JUA, N.; PRIATHASHINI, P.

2016-03-01

Biofuels including biodiesel, an alternative fuel, is renewable, environmentally friendly, non-toxic and low emissions. The raw material used in this work was coconut oil, which contained saturated fatty acids about 90% with high percentage of medium chain (C8-C12), especially lauric acid and myristic acid. The purpose of this research was to study the effect of power and NaOH catalyst in transesterification assisted by microwave for production of biofuels (biodiesel and bio-kerosene) derived from coconut oil. The reaction was performed with oil and methanol using mole ratio of 1:6, catalyst concentration of 0.6% with microwave power at 100W, 180W, 300W, 450W, 600W, and 850W. The reaction time was set at of 3, 5, 7, 10 and 15 min. The results showed that microwave could accelerate the transesterification process to produce biodiesel and bio-kerosene using NaOH catalyst. The highest yield of biodiesel was 97.17 %, or 99.05 % conversion at 5 min and 100W microwave power. Meanwhile, the bio-kerosene obtained was 65% after distillation.

Evaluation of Biodiesel Production, Engine Performance, and Emissions

NASA Astrophysics Data System (ADS)

Gürü, Metin; Keskïn, Ali

2016-08-01

Nowadays, to decrease environmental pollution and dependence on fossil-based fuels, research on alternative renewable energy sources has been increasing. One such renewable energy source is biodiesel, which is used as an alternative fuel for diesel engines. Biodiesel is renewable, nontoxic, biodegradable, and environmentally friendly. Biodiesel is domestically produced from vegetable oil (edible or nonedible), animal fat, and used cooking oils. In the biodiesel production process, oil or fat undergoes transesterification reaction through use of simple alcohols such as methanol, ethanol, propanol, butanol, etc. Use of methanol is most feasible because of its low cost, and physical and chemical advantages. Acid catalysis, alkali catalysis, and enzyme catalysis are usually used to improve the reaction rate and yield. Glycerol is a byproduct of the reaction and can be used as an industrial raw material. In this study, biodiesel production methods (direct use, pyrolysis, microemulsion, transesterification, supercritical processes, ultrasound- assisted, and microwave-assisted) and types of catalyst (homogeneous, heterogeneous, and enzyme) have been evaluated and compared. In addition, the effects of biodiesel and its blends on diesel engine performance and exhaust emissions are described and reviewed.

Fe(II)/Fe(III)-Catalyzed Intramolecular Didehydro-Diels-Alder Reaction of Styrene-ynes.

PubMed

Mun, Hyeon Jin; Seong, Eun Young; Ahn, Kwang-Hyun; Kang, Eun Joo

2018-02-02

The intramolecular didehydro-Diels-Alder reaction of styrene-ynes was catalyzed by Fe(II) and Fe(III) to produce various naphthalene derivatives under microwave heating conditions. Mechanistic calculations found that the Fe(II) catalyst activates the styrenyl diene in an inverse-electron-demand Diels-Alder reaction, and the consecutive dehydrogenation reaction can be promoted by either Fe(II)-catalyzed direct dehydrogenation or an Fe(III)-catalyzed rearomatization/dehydrogenation pathway.

Tailoring the Synergistic Bronsted-Lewis acidic effects in Heteropolyacid catalysts: Applied in Esterification and Transesterification Reactions.

PubMed

Tao, Meilin; Xue, Lifang; Sun, Zhong; Wang, Shengtian; Wang, Xiaohong; Shi, Junyou

2015-09-16

In order to investigate the influences of Lewis metals on acidic properties and catalytic activities, a series of Keggin heteropolyacid (HPA) catalysts, HnPW11MO39 (M = Ti(IV), Cu(II), Al(III), Sn(IV), Fe(III), Cr(III), Zr(IV) and Zn(II); for Ti and Zr, the number of oxygen is 40), were prepared and applied in the esterification and transesterification reactions. Only those cations with moderate Lewis acidity had a higher impact. Ti Substituted HPA, H5PW11TiO40, posse lower acid content compared with Ti(x)H(3-4x)PW12O40 (Ti partial exchanged protons in saturated H3PW12O40), which demonstrated that the Lewis metal as an addenda atom (H5PW11TiO40) was less efficient than those as counter cations (Ti(x)H(3-4x)PW12O40). On the other hand, the highest conversion reached 92.2% in transesterification and 97.4% in esterification. Meanwhile, a good result was achieved by H5PW11TiO40 in which the total selectivity of DAG and TGA was 96.7%. In addition, calcination treatment to H5PW11TiO40 make it insoluble in water which resulted in a heterogeneous catalyst feasible for reuse.

Tailoring the Synergistic Bronsted-Lewis acidic effects in Heteropolyacid catalysts: Applied in Esterification and Transesterification Reactions

PubMed Central

Tao, Meilin; Xue, Lifang; Sun, Zhong; Wang, Shengtian; Wang, Xiaohong; Shi, Junyou

2015-01-01

In order to investigate the influences of Lewis metals on acidic properties and catalytic activities, a series of Keggin heteropolyacid (HPA) catalysts, HnPW11MO39 (M = TiIV, CuII, AlIII, SnIV, FeIII, CrIII, ZrIV and ZnII; for Ti and Zr, the number of oxygen is 40), were prepared and applied in the esterification and transesterification reactions. Only those cations with moderate Lewis acidity had a higher impact. Ti Substituted HPA, H5PW11TiO40, posse lower acid content compared with TixH3−4xPW12O40 (Ti partial exchanged protons in saturated H3PW12O40), which demonstrated that the Lewis metal as an addenda atom (H5PW11TiO40) was less efficient than those as counter cations (TixH3−4xPW12O40). On the other hand, the highest conversion reached 92.2% in transesterification and 97.4% in esterification. Meanwhile, a good result was achieved by H5PW11TiO40 in which the total selectivity of DAG and TGA was 96.7%. In addition, calcination treatment to H5PW11TiO40 make it insoluble in water which resulted in a heterogeneous catalyst feasible for reuse. PMID:26374393

Tailoring the Synergistic Bronsted-Lewis acidic effects in Heteropolyacid catalysts: Applied in Esterification and Transesterification Reactions

NASA Astrophysics Data System (ADS)

Tao, Meilin; Xue, Lifang; Sun, Zhong; Wang, Shengtian; Wang, Xiaohong; Shi, Junyou

2015-09-01

In order to investigate the influences of Lewis metals on acidic properties and catalytic activities, a series of Keggin heteropolyacid (HPA) catalysts, HnPW11MO39 (M = TiIV, CuII, AlIII, SnIV, FeIII, CrIII, ZrIV and ZnII; for Ti and Zr, the number of oxygen is 40), were prepared and applied in the esterification and transesterification reactions. Only those cations with moderate Lewis acidity had a higher impact. Ti Substituted HPA, H5PW11TiO40, posse lower acid content compared with TixH3-4xPW12O40 (Ti partial exchanged protons in saturated H3PW12O40), which demonstrated that the Lewis metal as an addenda atom (H5PW11TiO40) was less efficient than those as counter cations (TixH3-4xPW12O40). On the other hand, the highest conversion reached 92.2% in transesterification and 97.4% in esterification. Meanwhile, a good result was achieved by H5PW11TiO40 in which the total selectivity of DAG and TGA was 96.7%. In addition, calcination treatment to H5PW11TiO40 make it insoluble in water which resulted in a heterogeneous catalyst feasible for reuse.

Analysis of biodiesel

USDA-ARS?s Scientific Manuscript database

Biodiesel is a biogenic alternative to diesel fuel derived from petroleum. It is produced by a transesterification reaction from materials consisting largely of triacylglycerols such as vegetable and other plant oils, animal fats, used cooking oils, and “alternative” feedstocks such as algal oils. T...

Synthesis of 1-methyleneindenes via palladium-catalyzed tandem reactions.

PubMed

Ye, Shengqing; Gao, Ke; Zhou, Haibo; Yang, Xiaodi; Wu, Jie

2009-09-28

Palladium-catalyzed tandem reactions of 2-alkenylphenyl-acetylenes with CuCl2 or CuBr2 afforded 3-chloro- or 3-bromo-1-methyleneindenes in good yields; these compounds could be further elaborated via palladium-catalyzed coupling reactions.

Solid-phase organic synthesis of difluoroalkyl entities using a novel fluorinating cleavage strategy: part 2. Synthesis of three small gem-difluorinated compound libraries using a dithiane linker.

PubMed

Wiehn, Matthias S; Fürniss, Daniel; Bräse, Stefan

2009-01-01

Three small compound biaryl libraries featuring a novel fluorinating cleavage strategy for preparation of a difluoromethyl group were assembled on solid supports. The average reaction yield per step was up to 96% in a synthetic sequence over five to six steps. Key features were Suzuki coupling reactions, transesterification with potassium cyanide and amidation reaction with trimethyl aluminum on solid supports.

A highly efficient synthesis of the FGH ring of micrandilactone A. Application of thioureas as ligands in the Co-catalyzed Pauson-Khand reaction and Pd-catalyzed carbonylative annulation.

PubMed

Tang, Yefeng; Zhang, Yandong; Dai, Mingji; Luo, Tuoping; Deng, Lujiang; Chen, Jiahua; Yang, Zhen

2005-03-03

The functionalized FGH ring system of micrandilactone A was successfully constructed in high selectivity and good yields. The key reactions in our strategy are the Co-thiourea-catalyzed stereoselective, intramolecular Pauson-Khand reaction and Pd-thiourea-catalyzed stereoselective, intramolecular annulation. [structure: see text

Use of Ceramic Material (cement Clinker) for the Production of Biodiesel

NASA Astrophysics Data System (ADS)

Soni, Sunny; Agarwal, Madhu

Biodiesel is a renewable liquid fuel made from natural, renewable biological sources such as edible and non edible oils. Over the last years, biodiesel has gained more market due to its benefits and because it appears as the natural substitute for diesel. Reasons for growing interest in biodiesel include its potential for reducing noxious emissions, potential contributions to rural economic development, as an additional demand center for agricultural commodities, and as a way to reduce reliance on foreign oil. Biodiesel was prepared from soybean oil by transesterification with methanol in the presence of cement clinker. Cement clinker was examined as a catalyst for a conversion of soybean oil to fatty acid methyl esters (FAMEs). It can be a promising heterogeneous catalyst for the production of biodiesel fuels from soybean oil because of high activity in the conversion and no leaching in the transesterification reaction. The reaction conditions were optimized. A study for optimizing the reaction parameters such as the reaction temperature, and reaction time, was carried out. The catalyst cement clinker composition was characterized by XRF. The results demonstrate that the cement clinker shows high catalytic performance & it was found that the yield of biodiesel can reach as high as 84.52% after 1 h reaction at 65°C, with a 6:1 molar ratio of methanol to oil, 21 wt% KOH/cement clinker as catalyst.

Representing Rate Equations for Enzyme-Catalyzed Reactions

ERIC Educational Resources Information Center

Ault, Addison

2011-01-01

Rate equations for enzyme-catalyzed reactions are derived and presented in a way that makes it easier for the nonspecialist to see how the rate of an enzyme-catalyzed reaction depends upon kinetic constants and concentrations. This is done with distribution equations that show how the rate of the reaction depends upon the relative quantities of…

Acetyl diacylglycerol produced by modified camelina (Camelina sativa)

USDA-ARS?s Scientific Manuscript database

Acetyl diacylglyceride (Acetyl-TAG) is a component of a commercial product, ACETEM, manufactured by transesterification reaction of triglycerides, glycerol, and triacetin or by acetylation of mono- and diglycerides with acetic acid anhydride. ACETEM is commonly used as foaming agents and coatings in...

Georges Chavanne and the first biodiesel

USDA-ARS?s Scientific Manuscript database

This article discusses the first production and use of a fuel around 1937 now called biodiesel, which is obtained from a vegetable or plant oil through a straightforward chemical reaction called transesterification. Biodiesel has become an alternative or supplement to conventional diesel fuel derive...

Transesterification of diethyl oxalate with phenol over sol-gel MoO(3)/TiO(2) catalysts.

PubMed

Kotbagi, Trupti; Nguyen, Duy Luan; Lancelot, Christine; Lamonier, Carole; Thavornprasert, Kaew-Arpha; Wenli, Zhu; Capron, Mickaël; Jalowiecki-Duhamel, Louise; Umbarkar, Shubhangi; Dongare, Mohan; Dumeignil, Franck

2012-08-01

The transesterification of diethyl oxalate (DEO) with phenol to form diphenyl oxalate (DPO) has been carried out in the liquid phase over very efficient MoO(3)/TiO(2) solid-acid sol-gel catalysts. A selectivity of 100 % with a remarkable maximum yield of 88 % were obtained, which opens the route to downstream phosgene-free processes for the synthesis of polycarbonates. Interpretation of the results of various acidity measurements (NH(3) and pyridine desorption, methanol oxidation as a probe reaction) allowed us to identify the catalytic sites as Lewis acid sites. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Unexpected Reaction Pathway for butyrylcholinesterase-catalyzed inactivation of “hunger hormone” ghrelin

NASA Astrophysics Data System (ADS)

Yao, Jianzhuang; Yuan, Yaxia; Zheng, Fang; Zhan, Chang-Guo

2016-02-01

Extensive computational modeling and simulations have been carried out, in the present study, to uncover the fundamental reaction pathway for butyrylcholinesterase (BChE)-catalyzed hydrolysis of ghrelin, demonstrating that the acylation process of BChE-catalyzed hydrolysis of ghrelin follows an unprecedented single-step reaction pathway and the single-step acylation process is rate-determining. The free energy barrier (18.8 kcal/mol) calculated for the rate-determining step is reasonably close to the experimentally-derived free energy barrier (~19.4 kcal/mol), suggesting that the obtained mechanistic insights are reasonable. The single-step reaction pathway for the acylation is remarkably different from the well-known two-step acylation reaction pathway for numerous ester hydrolysis reactions catalyzed by a serine esterase. This is the first time demonstrating that a single-step reaction pathway is possible for an ester hydrolysis reaction catalyzed by a serine esterase and, therefore, one no longer can simply assume that the acylation process must follow the well-known two-step reaction pathway.

Hierarchical Na-doped cubic ZrO{sub 2} synthesis by a simple hydrothermal route and its application in biodiesel production

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lara-García, Hugo A.; Romero-Ibarra, Issis C.; Pfeiffer, Heriberto, E-mail: pfeiffer@iim.unam.mx

Hierarchical growth of cubic ZrO{sub 2} phase was successfully synthesized via a simple hydrothermal process in the presence of different surfactants (cationic, non-ionic and anionic) and sodium hydroxide. The structural and microstructural characterizations of different ZrO{sub 2} powders were performed using various techniques, such as X-ray diffraction, transmission electron microscopy, N{sub 2} adsorption–desorption, scanning electron microscopy and infrared. Results indicated that sodium addition stabilized the cubic ZrO{sub 2} phase by a Na-doping process, independently of the surfactant used. In contrast, microstructural characteristics varied as a function of the surfactant and sodium presence. In addition, water vapor (H{sub 2}O) and carbonmore » dioxide (CO{sub 2}) sorption properties were evaluated on ZrO{sub 2} samples. Results evidenced that sample surface reactivity changed as a function of the sodium content. Finally, this surface reactivity was evaluated on the biodiesel transesterification reaction using the different synthesized samples, obtaining yields of 93%. - Graphical abstract: Hierarchical growth of cubic Na-ZrO{sub 2} phase was synthesized by hydrothermal processes in the presence of surfactants and sodium. Sodium addition stabilized the cubic phase by a Na-doping process, while the microstructural characteristics varied with surfactants. Finally, this surface reactivity was evaluated on the biodiesel transesterification reaction. - Highlights: • Cubic-ZrO{sub 2} phase was synthesized via a simple hydrothermal process. • ZrO{sub 2} structure and microstructures changed as a function of the surfactant. • Cubic-ZrO{sub 2} phase was evaluated on the biodiesel transesterification reaction.« less

Bifunctional heterogeneous catalysts from oil palm empty fruit bunches ash and alum for biodiesel synthesis simultaneously

NASA Astrophysics Data System (ADS)

Astar, Ismail; Usman, Thamrin; Wahyuni, Nelly; Rudiyansyah, Alimuddin, Andi Hairil

2017-03-01

Free fatty acids (FFA) contained in crude palm oil (CPO) and sludge oil has been used as the base material of biodiesel with the aid of a catalyst in the transesterification and esterification reactions. This study aims to synthesize and characterize bifunctional catalysts were synthesized from the ashes of palm empty fruit bunches (EFB) and alum based on the analysis of XRD, XRF and acidity test. Bifunctional catalyst obtained was used as a catalyst to production of biodiesel with different levels of FFA. The optimum ratio alum added was 0.2 mol at 3 hours of reaction time and 3% of catalyst by the FFA samples were used 67,40%. The catalyst with optimum alum mole variations subsequently used on samples with varying levels of FFA, namely 1.29%, 4.98%, 29.21%, 67.40% and 74.47%. Optimum conversion of methyl ester in the esterification reaction occurs in the sample with 67.40% FFA content, which reached 86.17%, while the conversion of methyl ester transesterification process optimum amounted to 45.70% in the samples with 4.98% FFA content. Methyl ester produced has a refractive index of 1.448 (29.8 ° C), density of 0.883 g / mL (25 °C) and a viscosity of 8.933 cSt (25 ° C). The results of GC-MS analysis showed that the main composition of methyl ester result of esterification of sludge oil methyl palmitate (36.84%), while the CPO transesterification shows the main composition of methyl ester is methyl oleic (38.87%). Based on the research results, the catalyst synthesized from alum and EFB ash can be used as a Bifunctional catalysts for biodiesel synthesis.

Effect of reactive agent and transesterification catalyst on properties of PLA/PBAT blends

NASA Astrophysics Data System (ADS)

Pitivut, S.; Suttiruengwong, S.; Seadan, M.

2015-07-01

This research aimed to study the properties of poly (lactic acid) (PLA)/poly (butylene adipate-co-terephthalate) (PBAT) blends with two different reactive systems: free radical reaction through peroxide (Perkadox) and transesterification catalyst (tetrabutyl titanate; TBT). Two blends composed of PLA as a matrix phase with the composition of 80 and 70 percent by weight. PLA/PBAT blends with Perkadox were prepared in twin screw extruder, whereas PLA/PBAT blends with TBT were prepared in an internal mixer. The morphology of the blends was investigated by scanning electron microscope (SEM). Tensile and impact testingsof the blends were reported. In case of the blends with Perkadox, SEM micrographs revealed that the size of particles was substantially reduced when adding more Perkadox. Young's modulus and the tensile strength of all blend ratios were insignificantly changed, whereas the elongation at break was decreased when compared to non-reactive blends due to the possible crosslinking reaction as observed from melt flow index (MFI) values. When adding Perkadox, the impact strength of PLA/PBAT (80/20) remained almost unchanged. However, the impact strength of PLA/PBAT (70/30) was enhanced, increasing to 110% for 0.05 phr Perkadox. In case of the blends with TBT, SEM micrographs showed the decrease in the particle size of PBAT phase when adding TBT. Young's modulus and the tensile strength of all blend ratios were not different, but the elongation at break was improved when adding TBT owing to the transesterification reaction. For PLA/PBAT (80/20), the elongation at break was increased by 39%, whereas the elongation at break was increased by 15% for PLA/PLA (70/30). The impact strength of all blend ratios unaffected.

Tandem reactions initiated by copper-catalyzed cross-coupling: a new strategy towards heterocycle synthesis.

PubMed

Liu, Yunyun; Wan, Jie-Ping

2011-10-21

Copper-catalyzed cross-coupling reactions which lead to the formation of C-N, C-O, C-S and C-C bonds have been recognized as one of the most useful strategies in synthetic organic chemistry. During past decades, important breakthroughs in the study of Cu-catalyzed coupling processes demonstrated that Cu-catalyzed reactions are broadly applicable to a variety of research fields related to organic synthesis. Representatively, employing these coupling transformations as key steps, a large number of tandem reactions have been developed for the construction of various heterocyclic compounds. These tactics share the advantages of high atom economics of tandem reactions as well as the broad tolerance of Cu-catalyst systems. Therefore, Cu-catalyzed C-X (X = N, O, S, C) coupling transformation-initiated tandem reactions were quickly recognized as a strategy with great potential for synthesizing heterocyclic compounds and gained worldwide attention. In this review, recent research progress in heterocycle syntheses using tandem reactions initiated by copper-catalyzed coupling transformations, including C-N, C-O, C-S as well as C-C coupling processes are summarized.

CFD simulation of fatty acid methyl ester production in bubble column reactor

NASA Astrophysics Data System (ADS)

Salleh, N. S. Mohd; Nasir, N. F.

2017-09-01

Non-catalytic transesterification is one of the method that was used to produce the fatty acid methyl ester (FAME) by blowing superheated methanol bubbles continuously into the vegetable oil without using any catalyst. This research aimed to simulate the production of FAME from palm oil in a bubble column reactor. Computational Fluid Dynamic (CFD) simulation was used to predict the distribution of fatty acid methyl ester and other product in the reactor. The fluid flow and component of concentration along the reaction time was investigated and the effects of reaction temperature (523 K and 563 K) on the non-catalytic transesterification process has been examined. The study was carried out using ANSYS CFX 17.1. The finding from the study shows that increasing the temperature leads to higher amount of fatty acid methyl ester can be produced in shorter time. On the other hand, concentration of the component such as triglyceride (TG), glycerol (GL) and fatty acid methyl ester (FAME) can be known when reaching the optimum condition.

Soybean biodiesel methyl esters, free glycerin and acid number quantification by 1H nuclear magnetic resonance spectroscopy.

PubMed

Coral, Natasha; Rodrigues, Elizabeth; Rumjanek, Victor; Zamian, José Roberto; da Rocha Filho, Geraldo Narciso; da Costa, Carlos Emmerson Ferreira

2013-02-01

Production of alternative fuels, such as biodiesel, from transesterification of vegetable oil driven by heterogeneous catalysts is a promising alternative to fossil diesel. However, achieving a successful substitution for a new renewable fuel depends on several quality parameters. (1)H NMR spectroscopy was used to determine the amount of methyl esters, free glycerin and acid number in the transesterification of soybean oil with methanol in the presence of hydrotalcite-type catalyst to produce biodiesel. Reaction parameters, such as temperature and time, were used to evaluate soybean oil methyl esters rate conversion. Temperatures of 100 to 180 °C and times of 20 to 240 min were tested on a 1 : 12 molar ratio soybean oil/methanol reaction. At 180 °C/240 min conditions, a rate of 94.5 wt% of methyl esters was obtained, where free glycerin and free fatty acids were not detected. Copyright © 2012 John Wiley & Sons, Ltd.

Wet in situ transesterification of spent coffee grounds with supercritical methanol for the production of biodiesel.

PubMed

Son, Jeesung; Kim, Bora; Park, Jeongseok; Yang, Jeongwoo; Lee, Jae W

2018-07-01

This work introduces biodiesel production from wet spent coffee grounds (SCGs) with supercritical methanol without any pre-drying process. Supercritical methanol and subcritical water effectively produced biodiesel via in situ transesterification by inducing more porous SCG and enhancing the efficiency of lipid extraction and conversion. It was also found that space loading was one of the critical factors for biodiesel production. An optimal biodiesel yield of 10.17 wt% of dry SCG mass (86.33 w/w% of esterifiable lipids in SCG) was obtained at reaction conditions of 270 °C, 90 bars, methanol to wet SCG ratio 5:1, space loading 58.4 ml/g and reaction time 20 min. Direct use of wet SCG waste as feedstock for supercritical biodiesel production eliminates the conventional dying process and the need of catalyst and also reduces environmental problems caused by landfill accumulation. Copyright © 2018 Elsevier Ltd. All rights reserved.

Encapsulated heterogeneous base catalysts onto SBA-15 nanoporous material as highly active catalysts in the transesterification of sunflower oil to biodiesel

NASA Astrophysics Data System (ADS)

Albayati, Talib M.; Doyle, Aidan M.

2015-02-01

Alkali metals and their hydroxides, Na, NaOH, Li, and LiOH, were encapsulated onto SBA-15 nanoporous material as highly active catalysts for the production of biodiesel fuel from sunflower oil. The incipient wetness impregnation method was adopted for the prepared catalysts. The characterization properties of the catalysts and unmodified SBA-15 were determined using X-ray diffraction, scanning electron microscopy, EDAX, nitrogen adsorption-desorption porosimetry (Brunauer-Emmett-Teller), Fourier-transform infrared spectroscopy, and transmission electron microscopy. Transesterification was conducted in a batch reactor at atmospheric pressure and 65 °C. The catalysts were highly active with yields of fatty acid methyl ester (FAME) in the range 96-99 %. Na/SBA-15 catalyst was reused for seven consecutive cycles under the same reaction conditions; the yield to FAME on the final cycle was 96 %. This study shows that the alkali metals and their hydroxides supported on SBA-15-based catalyst are excellent catalysts for the biodiesel reaction.

Synthesis of biodiesel from pongamia oil using heterogeneous ion-exchange resin catalyst.

PubMed

Jaya, N; Selvan, B Karpanai; Vennison, S John

2015-11-01

Biodiesel is a clean-burning renewable substitute fuel for petroleum. Biodiesel could be effectively produced by transesterification reaction of triglycerides of vegetable oils with short-chain alcohols in the presence of homogeneous or heterogeneous catalysts. Conventionally, biodiesel manufacturing processes employ strong acids or bases as catalysts. But, separation of the catalyst and the by-product glycerol from the product ester is too expensive to justify the product use as an automobile fuel. Hence heterogeneous catalysts are preferred. In this study, transesterification of pongamia oil with ethanol was performed using a solid ion-exchange resin catalyst. It is a macro porous strongly basic anion exchange resin. The process parameters affecting the ethyl ester yield were investigated. The reaction conditions were optimized for the maximum yield of fatty acid ethyl ester (FAEE) of pongamia oil. The properties of FAEE were compared with accepted standards of biodiesel. Engine performance was also studied with pongamia oil diesel blend and engine emission characteristics were observed. Copyright © 2015 Elsevier Inc. All rights reserved.

Structural insights into methanol-stable variants of lipase T6 from Geobacillus stearothermophilus.

PubMed

Dror, Adi; Kanteev, Margarita; Kagan, Irit; Gihaz, Shalev; Shahar, Anat; Fishman, Ayelet

2015-11-01

Enzymatic production of biodiesel by transesterification of triglycerides and alcohol, catalyzed by lipases, offers an environmentally friendly and efficient alternative to the chemically catalyzed process while using low-grade feedstocks. Methanol is utilized frequently as the alcohol in the reaction due to its reactivity and low cost. However, one of the major drawbacks of the enzymatic system is the presence of high methanol concentrations which leads to methanol-induced unfolding and inactivation of the biocatalyst. Therefore, a methanol-stable lipase is of great interest for the biodiesel industry. In this study, protein engineering was applied to substitute charged surface residues with hydrophobic ones to enhance the stability in methanol of a lipase from Geobacillus stearothermophilus T6. We identified a methanol-stable variant, R374W, and combined it with a variant found previously, H86Y/A269T. The triple mutant, H86Y/A269T/R374W, had a half-life value at 70 % methanol of 324 min which reflects an 87-fold enhanced stability compared to the wild type together with elevated thermostability in buffer and in 50 % methanol. This variant also exhibited an improved biodiesel yield from waste chicken oil compared to commercial Lipolase 100L® and Novozyme® CALB. Crystal structures of the wild type and the methanol-stable variants provided insights regarding structure-stability correlations. The most prominent features were the extensive formation of new hydrogen bonds between surface residues directly or mediated by structural water molecules and the stabilization of Zn and Ca binding sites. Mutation sites were also characterized by lower B-factor values calculated from the X-ray structures indicating improved rigidity.

Mechanism of acetaldehyde-induced deactivation of microbial lipases

PubMed Central

2011-01-01

Background Microbial lipases represent the most important class of biocatalysts used for a wealth of applications in organic synthesis. An often applied reaction is the lipase-catalyzed transesterification of vinyl esters and alcohols resulting in the formation of acetaldehyde which is known to deactivate microbial lipases, presumably by structural changes caused by initial Schiff-base formation at solvent accessible lysine residues. Previous studies showed that several lipases were sensitive toward acetaldehyde deactivation whereas others were insensitive; however, a general explanation of the acetaldehyde-induced inactivation mechanism is missing. Results Based on five microbial lipases from Candida rugosa, Rhizopus oryzae, Pseudomonas fluorescens and Bacillus subtilis we demonstrate that the protonation state of lysine ε-amino groups is decisive for their sensitivity toward acetaldehyde. Analysis of the diverse modification products of Bacillus subtilis lipases in the presence of acetaldehyde revealed several stable products such as α,β-unsaturated polyenals, which result from base and/or amino acid catalyzed aldol condensation of acetaldehyde. Our studies indicate that these products induce the formation of stable Michael-adducts at solvent-accessible amino acids and thus lead to enzyme deactivation. Further, our results indicate Schiff-base formation with acetaldehyde to be involved in crosslinking of lipase molecules. Conclusions Differences in stability observed with various commercially available microbial lipases most probably result from different purification procedures carried out by the respective manufacturers. We observed that the pH of the buffer used prior to lyophilization of the enzyme sample is of utmost importance. The mechanism of acetaldehyde-induced deactivation of microbial lipases involves the generation of α,β-unsaturated polyenals from acetaldehyde which subsequently form stable Michael-adducts with the enzymes. Lyophilization of the enzymes from buffer at pH 6.0 can provide an easy and effective way to stabilize lipases toward inactivation by acetaldehyde. PMID:21342514

Resting State and Elementary Steps of the Coupling of Aryl Halides with Thiols Catalyzed by Alkylbisphosphine Complexes of Palladium

PubMed Central

Alvaro, Elsa

2010-01-01

Detailed mechanistic studies on the coupling of aryl halides with thiols catalyzed by palladium complexes of the alkylbisphosphine ligand CyPF-tBu (1-dicyclohexylphosphino-2-di-tert-butylphosphinoethylferrocene) are reported. The elementary steps that constitute the catalytic cycle, i.e. oxidative addition, transmetalation and reductive elimination, have been studied, and their relative rates are reported. Each of the steps of the catalytic process occurs at temperatures that are much lower than those required for the reactions catalyzed by a combination of palladium precursors and CyPF-tBu. To explain these differences in rates between the catalytic and stoichiometric reactions, studies were conducted to identify the resting state of the catalyst of the reactions catalyzed by a combination of Pd(OAc)2 and CyPF-tBu, a combination of Pd(dba)2 and CyPF-tBu, or the likely intermediate Pd(CyPF-tBu)(Ar)(Br). These show that the major palladium complex in each case lies off of the catalytic cycle. The resting state of the reactions catalyzed by Pd(OAc)2 and CyPF-tBu was the palladium bis-thiolate complex [Pd(CyPF-tBu)(SR)2] (R = alkyl or aryl). The resting state in reactions catalyzed by Pd2(dba)3 and CyPF-tBu was the binuclear complex [Pd(CyPF-tBu)]2(μ2, η2-dba) (9). The resting state of reactions of both aromatic and aliphatic thiols catalyzed by [Pd(CyPF-tBu)(p-tolyl)(Br)] (3a) was the hydridopalladium thiolate complex [Pd(CyPF-tBu)(H)(SR)] (R= alkyl and aryl). All these palladium species have been prepared independently, and the mechanisms by which they enter the catalytic cycle have been examined in detail. These features of the reaction catalyzed by palladium and CyPF-tBu have been compared with those of reactions catalyzed by the alkylbisphosphine DiPPF and Pd(OAc)2 or Pd(dba)2. Our data indicate that the resting states of these reactions are similar to each other and that our mechanistic conclusions about reactions catalyzed by palladium and CyPF-tBu can be extrapolated to reactions catalyzed by complexes of other electron-rich bisphosphines. PMID:19453106

Electro-catalytic biodiesel production from canola oil in methanolic and ethanolic solutions with low cost stainless steel and hybrid ion-exchange resin grafted electrodes

NASA Astrophysics Data System (ADS)

Allioux, Francois-Marie; Holland, Brendan J.; Kong, Lingxue; Dumée, Ludovic F.

2017-07-01

Biodiesel is a growing alternative to petroleum fuels and is produced by the catalysed transesterification of fats in presence of an alcohol base. Transesterification processes using homogeneous catalysts are considered to be amongst the most efficient methods but rely on the feedstock quality and low water content in order to avoid undesirable saponification reactions. In this work, the electro-catalytic conversion of canola oil to biodiesel in a 1% aqueous methanolic and ethanolic reaction mixture was performed without the addition of external catalyst or co-solvent. An inexpensive stainless steel electrode and a hybrid stainless steel electrode coated with an ion-exchange resin catalyst were used as cathode materials while the anode was composed of a plain carbon paper. The cell voltages were varied from 10 to 40 V and the reaction temperature maintained at 20 or 40°C. The canola oil conversion rates were found to be superior at 40°C without saponification reactions for cell voltages below 30 V. The conversion rates were as high as 87% for the hybrid electrode and 81% for the plain stainless steel electrode. This work could inspire new process development for the conversion of high water content feedstock for the production of second-generation biodiesel.

Inverse problem analysis for identification of reaction kinetics constants in microreactors for biodiesel synthesis

NASA Astrophysics Data System (ADS)

Pontes, P. C.; Naveira-Cotta, C. P.

2016-09-01

The theoretical analysis for the design of microreactors in biodiesel production is a complicated task due to the complex liquid-liquid flow and mass transfer processes, and the transesterification reaction that takes place within these microsystems. Thus, computational simulation is an important tool that aids in understanding the physical-chemical phenomenon and, consequently, in determining the suitable conditions that maximize the conversion of triglycerides during the biodiesel synthesis. A diffusive-convective-reactive coupled nonlinear mathematical model, that governs the mass transfer process during the transesterification reaction in parallel plates microreactors, under isothermal conditions, is here described. A hybrid numerical-analytical solution via the Generalized Integral Transform Technique (GITT) for this partial differential system is developed and the eigenfunction expansions convergence rates are extensively analyzed and illustrated. The heuristic method of Particle Swarm Optimization (PSO) is applied in the inverse analysis of the proposed direct problem, to estimate the reaction kinetics constants, which is a critical step in the design of such microsystems. The results present a good agreement with the limited experimental data in the literature, but indicate that the GITT methodology combined with the PSO approach provide a reliable computational algorithm for direct-inverse analysis in such reactive mass transfer problems.

Structural basis for Diels-Alder ribozyme-catalyzed carbon-carbon bond formation

PubMed Central

Serganov, Alexander; Keiper, Sonja; Malinina, Lucy; Tereshko, Valentina; Skripkin, Eugene; Höbartner, Claudia; Polonskaia, Anna; Phan, Anh Tuân; Wombacher, Richard; Micura, Ronald; Dauter, Zbigniew; Jäschke, Andres; Patel, Dinshaw J

2015-01-01

The majority of structural efforts addressing RNA’s catalytic function have focused on natural ribozymes, which catalyze phosphodiester transfer reactions. By contrast, little is known about how RNA catalyzes other types of chemical reactions. We report here the crystal structures of a ribozyme that catalyzes enantioselective carbon-carbon bond formation by the Diels-Alder reaction in the unbound state and in complex with a reaction product. The RNA adopts a λ-shaped nested pseudoknot architecture whose preformed hydrophobic pocket is precisely complementary in shape to the reaction product. RNA folding and product binding are dictated by extensive stacking and hydrogen bonding, whereas stereoselection is governed by the shape of the catalytic pocket. Catalysis is apparently achieved by a combination of proximity, complementarity and electronic effects. We observe structural parallels in the independently evolved catalytic pocket architectures for ribozyme- and antibody-catalyzed Diels-Alder carbon-carbon bond-forming reactions. PMID:15723077

Ultrasonic-assisted production of biodiesel from transesterification of palm oil over ostrich eggshell-derived CaO catalysts.

PubMed

Chen, Guanyi; Shan, Rui; Shi, Jiafu; Yan, Beibei

2014-11-01

In this study, waste ostrich eggshell-derived calcium oxide (denoted as CaO(OE)) particles were synthesized and explored as cost-effective catalysts for the ultrasonic-assisted transesterification of palm oil. The physicochemical properties of the resultant catalysts were characterized by XRD, N2 adsorption, XRF and Hammett indicator, while the catalytic activity was evaluated through transesterification of palm oil with methanol under ultrasonic conditions. More specifically, the CaO(OE) showed comparable catalytic activity to the one derived from commercial calcium carbonate (denoted as CaO(Lab)). Moreover, under ultrasonic conditions, the catalytic activity of CaO(OE) could be enhanced significantly. The maximum yield of fatty acid methyl esters could reach 92.7% under the optimal condition of reaction time of 60 min with ultrasonic power of 60% (120 W), methanol-to-oil ratio of 9:1, and catalyst loading of 8 wt.%. The results indicated that the CaO(OE) catalysts showed good catalytic performance and reusability, and may potentially reduce the cost of biodiesel production. Copyright © 2014 Elsevier Ltd. All rights reserved.

Cogeneration of biodiesel and nontoxic rapeseed meal from rapeseed through in-situ alkaline transesterification.

PubMed

Qian, Junfeng; Yang, Qiuhui; Sun, Fuan; He, Mingyang; Chen, Qun; Yun, Zhi; Qin, Lizhen

2013-01-01

In-situ alkaline transesterification of rapeseed oil with methanol for the production of biodiesel and nontoxic rapeseed meal was carried out. Water removal from milled rapeseed by methanol washing was more effective than vacuum drying. The conversion rate of rapeseed oil into FAME was 92%, FAME mass was 8.81 g, glucosinolates content in remaining rapeseed meal was 0.12% by methanol washing, while by vacuum drying the values were 46%, 4.44 g, 0.58%, respectively. In the presence of 0.10 mol/L NaOH in methanol, with methanol/oil molar ratio of 180:1 and a 3h reaction at 40 °C, a conversion rate of 98% was achieved, and the glucosinolates content was reduce to 0.07%, a value which below the GB/T 22514-2008 standard in China. Thus the rapeseed meal can be used as a source of protein in animal feed. The FAME prepared through in-situ alkaline transesterification met the ASTM specifications for biodiesel. Copyright © 2012 Elsevier Ltd. All rights reserved.

Determining the fatty acid composition in plasma and tissues as fatty acid methyl esters using gas chromatography – a comparison of different derivatization and extraction procedures.

PubMed

Ostermann, Annika I; Müller, Maike; Willenberg, Ina; Schebb, Nils Helge

2014-12-01

Analysis of the fatty acid (FA) composition in biological samples is commonly carried out using gas liquid chromatography (GC) after transesterification to volatile FA methyl esters (FAME). We compared the efficacy of six frequently used protocols for derivatization of different lipid classes as well as for plasma and tissue samples. Transesterification with trimethylsulfonium hydroxide (TMSH) led to insufficient derivatization efficacies for polyunsaturated FAs (PUFA, <50%). Derivatization in presence of potassium hydroxide (KOH) failed at derivatizing free FAs (FFAs). Boron trifluoride (BF3) 7% in hexane/MeOH (1:1) was insufficient for the transesterification of cholesterol ester (CE) as well as triacylglycerols (TGs). In contrast, methanolic hydrochloric acid (HCl) as well as a combination of BF3 with methanolic sodium hydroxide (NaOH+BF3) were suitable for the derivatization of FFAs, polar lipids, TGs, and CEs (derivatization rate >80% for all tested lipids). Regarding plasma samples, all methods led to an overall similar relative FA pattern. However, significant differences were observed, for example, for the relative amount of EPA+DHA (n3-index). Absolute FA plasma concentrations differed considerably among the methods, with low yields for KOH and BF3. We also demonstrate that lipid extraction with tert-butyl methyl ether/methanol (MTBE/MeOH) is as efficient as the classical method according to Bligh and Dyer, making it possible to replace (environmentally) toxic chloroform.We conclude that HCl-catalyzed derivatization in combination with MeOH/MTBE extraction is the most appropriate among the methods tested for the analysis of FA concentrations and FA pattern in small biological samples. A detailed protocol for the analysis of plasma and tissues is included in this article.

Biodiesel from Seeds: An Experiment for Organic Chemistry

ERIC Educational Resources Information Center

Goldstein, Steven W.

2014-01-01

Plants can store the chemical energy required by their developing offspring in the form of triglycerides. These lipids can be isolated from seeds and then converted into biodiesel through a transesterification reaction. This second-year undergraduate organic chemistry laboratory experiment exemplifies the conversion of an agricultural energy…

Direct conversion of wet algae to crude biodiesel under supercritical ethanol conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, Harvind K.; Muppaneni, Tapaswy; Patil, Prafulla D.

This paper presents a single-step, environmentally friendly approach for the direct conversion of wet algae to crude biodiesel under supercritical ethanol conditions. Ethanol was used for the simultaneous extraction and transesterification of lipids in algae to produce fatty acid ethyl esters at supercritical conditions. In this work the effects of process parameters dry algae to ethanol (wt./vol.) ratio (1:6-1:15), reaction temperature (245-270 C), and reaction time (2-30 min.) on the yield of fatty acid ethyl esters (FAEE) were studied. 67% conversion was achieved at 265 C and 20 min of reaction time. The calorific value of a purified biodiesel samplemore » produced at optimum conditions was measured to be 43 MJ/kg, which is higher than that of fatty acid methyl esters produced from the same biomass. The purified fatty acid ethyl esters were analyzed using GC-MS and FTIR. TGA analysis of algal biomass and purified FAEE was presented along with TEM images of the biomass captured before and after supercritical ethanol transesterification. This green conversion process has the potential to provide an energy-efficient and economical route for the production of renewable biodiesel production.« less

Synthesis of solid catalyst from egg shell waste and clay for biodiesel production

NASA Astrophysics Data System (ADS)

Setiadji, S.; Sundari, C. D. D.; Munir, M.; Fitriyah, S.

2018-05-01

Until now, energy consumption in Indonesia is almost entirely fulfilled by fossil fuels, thus, its availability will be limited and continue to decrease. To overcome these problems, development and utilization of renewable energy are required, one of which is biodiesel. Biodiesel can be prepared through transesterification reaction of vegetable oil using catalyst. In this research, a solid catalyst for biodiesel synthesis was prepared from chicken egg shell waste and clay. Optimization of the transesterification reaction of coconut (Cocos nucifera) oil to obtain biodiesel was also carried out. The formation of CaO/kaolin catalyst was confirmed based on the results of XRD and SEM-EDS. This catalyst is suitable for biodiesel synthesis from vegetable oils with lower FFA (free fatty acid) levels, i.e. coconut oil with FFA level of 0.18%. Based on FTIR result, FFA level and flame tests, it was found that biodiesel was successfully formed. Synthesis of biodiesel has the optimum conditions on reaction time of 16 hours and temperature of 64 °C, with oil: methanol ratio of 1: 15 and CaO/kaolin catalyst concentration of 0.9% in a reflux system.

Solid Catalyst Nanoparticles derived from Oil-Palm Empty Fruit Bunches (OP-EFB) as a Renewable Catalyst for Biodiesel Production

NASA Astrophysics Data System (ADS)

Husin, H.; Asnawi, T. M.; Firdaus, A.; Husaini, H.; Ibrahim, I.; Hasfita, F.

2018-05-01

Solid nanocatalyst derived from oil-palm empty fruit bunches (OP-EFB) fiber was successfully synthesized and its application for biodiesel production was investigated. The OPEFB was treated by burning, milling and heating methods to generate ashes in a nanoparticle size. The nanoparticle palm-bunch ash was characterized by scanning electron microscopy (SEM) and x-ray diffraction (XRD). The effects of the calcination temperature and catalyst amounts for transesterification reactions were investigated. XRD analysis of palm bunch ash exhibited that the highest composition of peaks characteristic were potassium oxide (K2O). SEM analysis showed that the nano palm bunch ash have a particle size ranging of 150-400 nm. The highest conversion of palm-oil to biodiesel reach to 97.90% was observed by using of palm bunch ash nanocatalyst which heated at 600°C, 3 h reaction time and 1% catalyst amount. Reusability of palm bunch ash catalysts was also examined. It was found that of its high active sites, reusable solid catalyst was obtained by just heating of palm bunch ash. It has a capability to reduce not only the amount of catalyst consumption but also reduce the reaction time of transesterification process.

Practical Iron- and Cobalt-Catalyzed Cross-Coupling Reactions between N-Heterocyclic Halides and Aryl or Heteroaryl Magnesium Reagents.

PubMed

Kuzmina, Olesya M; Steib, Andreas K; Fernandez, Sarah; Boudot, Willy; Markiewicz, John T; Knochel, Paul

2015-05-26

The reaction scope of iron- and cobalt-catalyzed cross-coupling reactions in the presence of isoquinoline (quinoline) in the solvent mixture tBuOMe/THF has been further investigated. Various 2-halogenated pyridine, pyrimidine, and triazine derivatives were arylated under these mild conditions in excellent yields. The presence of isoquinoline allows us to perform Fe-catalyzed cross-coupling reactions between 6-chloroquinoline and aryl magnesium reagents. Furthermore, it was found that the use of 10% N,N-dimethylquinoline-8-amine increases the yields of some Co-catalyzed cross-coupling reactions with chloropyridines bearing electron-withdrawing substituents. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chemical modification of nanocellulose with canola oil fatty acid methyl ester

Treesearch

Liqing Wei; Umesh P. Agarwal; Kolby C. Hirth; Laurent M. Matuana; Ronald C. Sabo; Nicole M. Stark

2017-01-01

Cellulose nanocrystals (CNCs), produced from dissolving wood pulp, were chemically functionalized by transesterification with canola oil fatty acid methyl ester (CME). CME performs as both the reaction reagent and solvent. Transesterified CNC (CNCFE) was characterized for their chemical structure, morphology, crystalline structure, thermal stability, and hydrophobicity...

The Depolymerization of Poly(Ethylene Terephthalate) (PET) Using N-Heterocyclic Carbenes from Ionic Liquids

ERIC Educational Resources Information Center

Kamber, Nahrain E.; Tsujii, Yasuhito; Keets, Kate; Waymouth, Robert M.; Pratt, Russell C.; Nyce, Gregory W.; Hedrick, James L.

2010-01-01

The depolymerization of the plastic polyethylene terephthalate (PET or PETE) is described in this laboratory procedure. The transesterification reaction used to depolymerize PET employs a highly efficient N-heterocyclic carbene catalyst derived from a commercially available imidazolium ionic liquid. N-heterocyclic carbenes are potent nucleophilic…

Existence of efficient divalent metal ion-catalyzed and inefficient divalent metal ion-independent channels in reactions catalyzed by a hammerhead ribozyme

PubMed Central

Zhou, Jing-Min; Zhou, De-Min; Takagi, Yasuomi; Kasai, Yasuhiro; Inoue, Atsushi; Baba, Tadashi; Taira, Kazunari

2002-01-01

The hammerhead ribozyme is generally accepted as a well characterized metalloenzyme. However, the precise nature of the interactions of the RNA with metal ions remains to be fully defined. Examination of metal ion-catalyzed hammerhead reactions at limited concentrations of metal ions is useful for evaluation of the role of metal ions, as demonstrated in this study. At concentrations of Mn2+ ions from 0.3 to 3 mM, addition of the ribozyme to the reaction mixture under single-turnover conditions enhances the reaction with the product reaching a fixed maximum level. Further addition of the ribozyme inhibits the reaction, demonstrating that a certain number of divalent metal ions is required for proper folding and also for catalysis. At extremely high concentrations, monovalent ions, such as Na+ ions, can also serve as cofactors in hammerhead ribozyme-catalyzed reactions. However, the catalytic efficiency of monovalent ions is extremely low and, thus, high concentrations are required. Furthermore, addition of monovalent ions to divalent metal ion-catalyzed hammerhead reactions inhibits the divalent metal ion-catalyzed reactions, suggesting that the more desirable divalent metal ion–ribozyme complexes are converted to less desirable monovalent metal ion–ribozyme complexes via removal of divalent metal ions, which serve as a structural support in the ribozyme complex. Even though two channels appear to exist, namely an efficient divalent metal ion-catalyzed channel and an inefficient monovalent metal ion-catalyzed channel, it is clear that, under physiological conditions, hammerhead ribozymes are metalloenzymes that act via the significantly more efficient divalent metal ion-dependent channel. Moreover, the observed kinetic data are consistent with Lilley’s and DeRose’s two-phase folding model that was based on ground state structure analyses. PMID:12034824

First Novozym 435 lipase-catalyzed Morita-Baylis-Hillman reaction in the presence of amides.

PubMed

Tian, Xuemei; Zhang, Suoqin; Zheng, Liangyu

2016-03-01

The first Novozym 435 lipase-catalyzed Morita-Baylis-Hillman (MBH) reaction with amides as co-catalyst was realized. Results showed that neither Novozym 435 nor amide can independently catalyze the reaction. This co-catalytic system that used a catalytic amount of Novozym 435 with a corresponding amount of amide was established and optimized. The MBH reaction strongly depended on the structure of aldehyde substrate, amide co-catalyst, and reaction additives. The optimized reaction yield (43.4%) was achieved in the Novozym 435-catalyzed MBH reaction of 2, 4-dinitrobenzaldehyde and cyclohexenone with isonicotinamide as co-catalyst and β-cyclodextrin as additive only in 2 days. Although enantioselectivity of Novozym 435 was not found, the results were still significant because an MBH reaction using lipase as biocatalyst was realized for the first time. Copyright © 2015 Elsevier Inc. All rights reserved.

New finding and optimal production of a novel extracellular alkaline lipase from Yarrowia lipolytica NRRL Y-2178.

PubMed

Lee, Geon-Ho; Bae, Jae-Han; Suh, Min-Jung; Kim, In-Hwan; Hou, Ching T; Kim, Hak-Ryul

2007-06-01

Lipases are industrially useful versatile enzymes that catalyze numerous different reactions including hydrolysis of triglycerides, transesterification, and chiral synthesis of esters under natural conditions. Although lipases from various sources have been widely used in industrial applications, such as in food, chemical, pharmaceutical, and detergent industries, there are still substantial current interests in developing new microbial lipases, specifically those functioning in abnormal conditions. We screened 17 lipase-producing yeast strains, which were prescreened for substrate specificity of lipase from more than 500 yeast strains from the Agricultural Research Service Culture Collection (Peoria, IL, U.S.A.), and selected Yarrowia lipolytica NRRL Y-2178 as a best lipase producer. This report presents new finding and optimal production of a novel extracellular alkaline lipase from Y. lipolytica NRRL Y-2178. Optimal c ulture conditions f orlipase production by Y. lipolytica NRRL Y-2178 were 72 h incubation time, 27.5 degrees C, pH 9.0. Glycerol and glucose were efficiently used as the most efficient carbon sources, and a combination of yeast extract and peptone was a good nitrogen source for lipase production by Y. lipolytica NRRL Y-2178. These results suggested that Y. lipolytica NRRL Y-2178 showsgood industrial potential as a new alkaline lipase producer.

Nickel-Catalyzed Coupling of Alkenes, Aldehydes, and Silyl Triflates

PubMed Central

Ng, Sze-sze; Ho, Chun-Yu; Jamison, Timothy F.

2011-01-01

A full account of two recently developed nickel-catalyzed coupling reactions of alkenes, aldehydes and silyl triflates is presented. These reactions provide either allylic alcohol or homoallylic alcohol derivatives selectively, depending on the ligand employed. These processes are believed to be mechanistically distinct from Lewis acid-catalyzed carbonyl-ene reactions, and several lines of evidence supporting this hypothesis are discussed. PMID:16939275

Reaction pathways and free energy profiles for cholinesterase-catalyzed hydrolysis of 6-monoacetylmorphine

PubMed Central

Qiao, Yan; Han, Keli; Zhan, Chang-Guo

2014-01-01

As the most active metabolite of heroin, 6-monoacetylmorphine (6-MAM) can penetrate into the brain for the rapid onset of heroin effects. The primary enzymes responsible for the metabolism of 6-MAM to the less potent morphine in humans are acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The detailed reaction pathways for AChE- and BChE-catalyzed hydrolysis of 6-MAM to morphine have been explored, for the first time, in the present study by performing first-principles quantum mechanical/molecular mechanical free energy calculations. It has been demonstrated that the two enzymatic reaction processes follow the similar catalytic reaction mechanism, and the whole catalytic reaction pathway for each enzyme consists of four reaction steps. According to the calculated results, the second reaction step associated with the transition state TS2a/TS2b should be rate-determining for the AChE/BChE-catalyzed hydrolysis, and the free energy barrier calculated for the AChE-catalyzed hydrolysis (18.3 kcal/mol) is 2.5 kcal/mol lower than that for the BChE-catalyzed hydrolysis (20.8 kcal/mol). The free energy barriers calculated for the AChE- and BChE-catalyzed reactions are in good agreement with the experimentally derived activation free energies (17.5 and 20.7 kcal/mol for the AChE- and BChE-catalyzed reactions, respectively). Further structural analysis reveals that the aromatic residues Phe295 and Phe297 in the acyl pocket of AChE (corresponding to Leu286 and Val288 in BChE) contribute to the lower energy of TS2a relative to TS2b. The obtained structural and mechanistic insights could be valuable for use in future rational design of a novel therapeutic treatment of heroin abuse. PMID:24595354

Copper-Catalyzed Sulfonyl Azide-Alkyne Cycloaddition Reactions: Simultaneous Generation and Trapping of Copper-Triazoles and -Ketenimines for the Synthesis of Triazolopyrimidines.

PubMed

Nallagangula, Madhu; Namitharan, Kayambu

2017-07-07

First simultaneous generation and utilization of both copper-triazole and -ketenimine intermediates in copper-catalyzed sulfonyl azide-alkyne cycloaddition reactions is achieved for the one-pot synthesis of triazolopyrimidines via a novel copper-catalyzed multicomponent cascade of sulfonyl azides, alkynes, and azirines. Significantly, the reaction proceeds under very mild conditions in good yields.

Mechanistic diversity in the RuBisCO superfamily: RuBisCO from Rhodospirillum rubrum is not promiscuous for reactions catalyzed by RuBisCO-like proteins.

PubMed

Warlick, Benjamin P E; Imker, Heidi J; Sriram, Jaya; Tabita, F Robert; Gerlt, John A

2012-11-27

d-Ribulose 1,5-bisphosphate carboxylase/oxygenases (RuBisCOs) are promiscuous, catalyzing not only carboxylation and oxygenation of d-ribulose 1,5-bisphosphate but also other promiscuous, presumably nonphysiological, reactions initiated by abstraction of the 3-proton of d-ribulose 1,5-bisphosphate. Also, RuBisCO has homologues that do not catalyze carboxylation; these are designated RuBisCO-like proteins or RLPs. Members of the two families of RLPs catalyze reactions in the recycling of 5'-methylthioadenosine (MTA) generated by polyamine synthesis: (1) the 2,3-diketo-5-methylthiopentane 1-phosphate (DK-MTP 1-P) "enolase" reaction in the well-known "methionine salvage" pathway in Bacillus sp. and (2) the 5-methylthio-d-ribulose 1-phosphate (MTRu 1-P) 1,3-isomerase reaction in the recently discovered "MTA-isoprenoid shunt" that generates 1-deoxy-d-xylulose 5-phosphate for nonmevalonate isoprene synthesis in Rhodospirillum rubrum. We first studied the structure and reactivity of DK-MTP 1-P that was reported to decompose rapidly [Ashida, H., Saito, Y., Kojima, C., and Yokota, A. (2008) Biosci., Biotechnol., Biochem. 72, 959-967]. The 2-carbonyl group of DK-MTP 1-P is rapidly hydrated and can undergo enolization both nonenzymatically and enzymatically via the small amount of unhydrated material that is present. We then examined the ability of RuBisCO from R. rubrum to catalyze both of the RLP-catalyzed reactions. Contrary to a previous report [Ashida, H., Saito, Y., Kojima, C., Kobayashi, K., Ogasawara, N., and Yokota, A. (2003) Science 302, 286-290], we were unable to confirm that this RuBisCO catalyzes the DK-MTP 1-P "enolase" reaction either in vitro or in vivo. We also determined that this RuBisCO does not catalyze the MTRu 1-P 1,3-isomerase reaction in vitro. Thus, although RuBisCOs can be functionally promiscuous, RuBisCO from R. rubrum is not promiscuous for either of the known RLP-catalyzed reactions.

Bis(amino)cyclopropenylidene (BAC) catalyzed aza-benzoin reaction.

PubMed

Wilde, Myron M D; Gravel, Michel

2014-10-17

A bis(amino)cyclopropenylidene (BAC) catalyzed aza-benzoin reaction between aldehydes and phosphinoyl imines has been developed. The reaction is general with a wide range of aromatic aldehydes and aromatic imines. The reaction displays excellent chemoselectivity favoring aza-benzoin products over homobenzoin products.

Recent advances in copper-catalyzed asymmetric coupling reactions

PubMed Central

2015-01-01

Summary Copper-catalyzed (or -mediated) asymmetric coupling reactions have received significant attention over the past few years. Especially the coupling reactions of aryl or alkyl halides with nucleophiles became a very powerful tool for the formation of C–C, C–N, C–O and other carbon–heteroatom bonds as well as for the construction of heteroatom-containing ring systems. This review summarizes the recent progress in copper-catalyzed asymmetric coupling reactions for the formation of C–C and carbon–heteroatom bonds. PMID:26734106

A new route to methyl (R,E)-(-)-tetradeca-2,4,5-trienoate (pheromone of Acanthoscelides obtectus) utilizing a palladium-catalyzed asymmetric allene formation reaction.

PubMed

Ogasawara, Masamichi; Nagano, Takashi; Hayashi, Tamio

2005-07-08

[reaction: see text] A formal total synthesis of the sex attractant of male dried bean beetle, methyl (R,E)-(-)-tetradeca-2,4,5-trienoate, was achieved by a new efficient route utilizing the Pd-catalyzed asymmetric allene synthesis reaction. It was found that the atropisomeric biaryl bisphosphine (R)-segphos showed better enantioselectivity than (R)-binap in the Pd-catalyzed reaction for preparing alkyl-substituted axially chiral allenes.

Ring-Opening Polymerization of Lactide to Form a Biodegradable Polymer

ERIC Educational Resources Information Center

Robert, Jennifer L.; Aubrecht, Katherine B.

2008-01-01

In this laboratory activity for introductory organic chemistry, students carry out the tin(II) bis(2-ethylhexanoate)/benzyl alcohol mediated ring-opening polymerization of lactide to form the biodegradable polymer polylactide (PLA). As the mechanism of the polymerization is analogous to that of a transesterification reaction, the experiment can be…

Evaluating Sustainability: Soap versus Biodiesel Production from Plant Oils

ERIC Educational Resources Information Center

Pohl, Nicola L. B.; Streff, Jennifer M.; Brokman, Steve

2012-01-01

Herein we describe a series of experiments for the undergraduate organic laboratory curriculum in which various plant oils (soybean, rapeseed, and olive) are subjected to saponification and transesterification reactions to create a set of compounds that can function as soaps or as fuels. The experiments introduce students to and asks them to…

Utilization of eggshell waste as low-cost solid base catalyst for biodiesel production from used cooking oil

NASA Astrophysics Data System (ADS)

Asri, N. P.; Podjojono, B.; Fujiani, R.; Nuraini

2017-05-01

A solid CaO-based catalyst of waste eggshell was developed for biodiesel production from used cooking oil. The waste eggshell powder was calcined in air at 90° C for 4 h to convert calcium species in the eggshells into active CaO catalysts. The characterization of CaO catalyst was done by XRD and BET analysis. The CaO catalyst was then introduced for transesterification of used cooking oil (UCO) for testing of its catalytic activity. The experiment was conducted in batch type reactor that consists of three-neck glass equipped by reflux condenser and magnetic stirrer. Before tranesterification process, the UCO was treated by coconut coir powder in order to reduce the free fatty acid content. The result showed that the catalyst was potentially use for transesterification of used cooking oil into biodiesel with relatively high yield of 75.92% was achieved at reaction temperature, reaction time, molar ratio UCO to methanol and catalyst amount of 65° C, 7 h, 1:15 and 6%, respectively.

Biodiesel Derive Bio-oil of Hermetia illucens Pre-pupae Catalysed by Sulphonated Biochar

NASA Astrophysics Data System (ADS)

Yoong Leong, Siew; Chong, Soo Shin; Chin, Kah Seng

2018-03-01

This study investigates the development of biochar catalyst from bamboo applied for biodiesel synthesis. A non-conventional biodiesel feedstock was used in the in-situ transesterification reaction. This non-conventional feedstock is obtained from an insect's fly, the Hermetia illucens fly. Biochar derived from bamboo has been investigated as a promising catalyst for biodiesel synthesis. The biochar acid catalysts were prepared by sulphonation via impregnation with concentrated sulphuric acid. The prepared catalysts were investigated for their performance to catalyse in-situ transesterification via ultra-sonication of Hermetia illucens bio-oil. The effects of carbonisation time (1 hour and 2 hour) and temperature (400°C, 500°C and 600°C) as well as catalyst loading (5-20 wt% on oil basis) on the transesterification yield were studied. Result showed that the highest yield of FAME obtained was 95.6% with catalyst loading of 15 wt% carbonized at 500°C for 2 hours. Sharp band of methyl ester functional groups were observed in the FTIR spectra at 1735-1750cm-1. The composition of this methyl ester was further deduced using gas chromatography and the fatty acid was predominantly lauric acid.

Practical method for the confirmation of authentic flours of different types of cereals and pseudocereals.

PubMed

Ačanski, Marijana M; Vujić, Djura N; Psodorov, Djordje B

2015-04-01

Gas chromatography with mass spectrometry was used to perform a qualitative analysis of the liposoluble flour extract of different types of cereals (bread wheat and spelt) and pseudocereals (amaranth and buckwheat). In addition to major fatty acids, the liposoluble extract also contained minor fatty acids with more than 20 carbon atoms, higher hydrocarbons and phytosterols. TMSH (trimethylsulfonium hydroxide, 0.2 mol/l in methanol) was used as a trans-esterification reagent. In a trans-esterification reaction, triglycerides esterified from acilglycerols to methyl-esters. SIM (selected ion monitoring) was applied to isolate fatty acid methyl esters on TIC (total ion current) chromatograms, using the 74 Da fragment ion, which originated from McLafferty rearrangement, and is typical for methyl-esters. GC-MS system was used for the trans-esterification of triglycerides to fatty acid methyl esters in the gas chromatographic injector. This eliminated laboratory preparation for fatty acid methyl esters. Cluster analysis was applied to compare the liposoluble flour extract from different types of cereals and pseudocereals. Statistical data showed the liposoluble extract analysis enabled determination of flour origin and, because the results were unambiguous, this approach could be used for quality control. Copyright © 2014 Elsevier Ltd. All rights reserved.

Diazo compounds and N-tosylhydrazones: novel cross-coupling partners in transition-metal-catalyzed reactions.

PubMed

Xiao, Qing; Zhang, Yan; Wang, Jianbo

2013-02-19

Transition-metal-catalyzed carbene transformations and cross-couplings represent two major reaction types in organometallic chemistry and organic synthesis. However, for a long period of time, these two important areas have evolved separately, with essentially no overlap or integration. Thus, an intriguing question has emerged: can cross-coupling and metal carbene transformations be merged into a single reaction cycle? Such a combination could facilitate the development of novel carbon-carbon bond-forming methodologies. Although this concept was first explored about 10 years ago, rapid developments inthis area have been achieved recently. Palladium catalysts can be used to couple diazo compounds with a wide variety of organic halides. Under oxidative coupling conditions, diazo compounds can also react with arylboronic acids and terminal alkynes. Both of these coupling reactions form carbon-carbon double bonds. As the key step in these catalytic processes, Pd carbene migratory insertion plays a vital role in merging the elementary steps of Pd intermediates, leading to novel carbon-carbon bond formations. Because the diazo substrates can be generated in situ from N-tosylhydrazones in the presence of base, the N-tosylhydrazones can be used as reaction partners, making this type of cross-coupling reaction practical in organic synthesis. N-Tosylhydrazones are easily derived from the corresponding aldehydes or ketones. The Pd-catalyzed cross-coupling of N-tosylhydrazones is considered a complementary reaction to the classic Shapiro reaction for converting carbonyl functionalities into carbon-carbon double bonds. It can also serve as an alternative approach for the Pd-catalyzed cross-coupling of carbonyl compounds, which is usually achieved via triflates. The combination of carbene formation and cross-coupling in a single catalytic cycle is not limited to Pd-catalyzed reactions. Recent studies of Cu-, Rh-, Ni-, and Co-catalyzed cross-coupling reactions with diazo compounds or N-tosylhydrazones show that these transformations also work with other transition metals, demonstrating the generality of the diazo compounds as new cross-coupling partners in transition-metal-catalyzed coupling reactions.

Viscous Flow Behaviour of Karanja Oil Based Bio-lubricant Base Oil.

PubMed

Sharma, Umesh Chandra; Sachan, Sadhana; Trivedi, Rakesh Kumar

2018-01-01

Karanja oil (KO) is widely used for synthesis of bio-fuel karanja oil methyl ester (KOME) due to its competitive price, good energy values and environmentally friendly combustion properties. Bio-lubricant is another value added product that can be synthesized from KO via chemical modification. In this work karanja oil trimethylolpropane ester (KOTMPE) bio-lubricant was synthesized and evaluated for its viscous flow behaviour. A comparison of viscous flow behaviours of natural KO and synthesized bio-fuel KOME and bio-lubricant KOTMPE was also made. The aim of this comparison was to validate the superiority of KOTMPE bio-lubricant over its precursors KO and KOME in terms of stable viscous flow at high temperature and high shear rate conditions usually encountered in engine operations and industrial processes. The free fatty acid (FFA) content of KO was 5.76%. KOME was synthesized from KO in a two-step, acid catalyzed esterification followed by base catalyzed transesterification, process at 65°C for 5 hours with oil-methanol ratio 1:6, catalysts H 2 SO 4 and KOH (1 and 1.25% w/w KO, respectively). In the final step, KOTMPE was prepared from KOME via transesterification with trimethylolpropane (TMP) at 150°C for 3 hours with KOME-TMP ratio 4:1 and H 2 SO 4 (2% w/w KOME) as catalyst. The viscosity versus temperature studies were made at 0-80°C temperatures in shear rate ranges of 10-1000 s -1 using a Discovery Hybrid Rheometer, model HR-3 (TA instruments, USA). The study found that viscosities of all three samples decreased with increase in temperature, though KOTMPE was able to maintain a good enough viscosity at elevated temperatures due to chemical modifications in its molecular structure. The viscosity index (VI) value for KOTMPE was 206.72. The study confirmed that the synthesized bio-lubricant KOTMPE can be used at high temperatures as a good lubricant, though some additives may be required to improve properties other than viscosity.

Conformation Analysis of T1 Lipase on Alcohols Solvent using Molecular Dynamics Simulation

NASA Astrophysics Data System (ADS)

Putri, A. M.; Sumaryada, T.; Wahyudi, S. T.

2017-07-01

Biodiesel usually is produced commercially via a transesterification reaction of vegetable oil with alcohol and alkali catalyst. The alkali catalyst has some drawbacks, such as the soap formation during the reaction. T1 Lipase enzyme had been known as a thermostable biocatalyst which is able to produce biodiesel through a cleaner process. In this paper the performance of T1 lipase enzyme as catalyst for transesterification reaction in pure ethanol, methanol, and water solvents were studied using a Molecular Dynamics (MD) Simulation at temperature of 300 K for 10 nanoseconds. The results have shown that in general the conformation of T1 lipase enzyme in methanol is more dynamics as shown by the value of root mean square deviation (RMSD), root mean squared fluctuation (RMSF), and radius of gyration. The highest solvent accessible surface area (SASA) total was also found in methanol due to the contribution of non-polar amino acid in the interior of the protein. Analysis of MD simulation has also revealed that the enzyme structure tend to be more rigid in ethanol environment. The analysis of electrostatic interactions have shown that Glu359-Arg270 salt-bridge pair might hold the key of thermostability of T1 lipase enzyme as shown by its strong and stable binding in all three solvents.

NHC-Catalyzed Asymmetric Benzoin Reaction in Water.

PubMed

Yan, Jun; Sun, Rong; Shi, Kuangxi; Li, Kai; Yang, Limin; Zhong, Guofu

2018-06-11

A chiral NHC-catalyzed benzoin condensation reaction in water was developed, thereby affording α-hydroxy ketones in good to high yields and high enantioselectivities. Water was proposed as a proton shuttle in the aqueous asymmetric condensation reaction.

Sequential Aldol Condensation – Transition Metal-Catalyzed Addition Reactions of Aldehydes, Methyl Ketones and Arylboronic Acids

PubMed Central

Liao, Yuan-Xi; Xing, Chun-Hui; Israel, Matthew; Hu, Qiao-Sheng

2011-01-01

Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form β-substituted ketones is described. By using the 1,1′-spirobiindane-7,7′-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access β-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step. PMID:21417359

Sequential aldol condensation-transition metal-catalyzed addition reactions of aldehydes, methyl ketones, and arylboronic acids.

PubMed

Liao, Yuan-Xi; Xing, Chun-Hui; Israel, Matthew; Hu, Qiao-Sheng

2011-04-15

Sequential aldol condensation of aldehydes with methyl ketones followed by transition metal-catalyzed addition reactions of arylboronic acids to form β-substituted ketones is described. By using the 1,1'-spirobiindane-7,7'-diol (SPINOL)-based phosphite, an asymmetric version of this type of sequential reaction, with up to 92% ee, was also realized. Our study provided an efficient method to access β-substituted ketones and might lead to the development of other sequential/tandem reactions with transition metal-catalyzed addition reactions as the key step. © 2011 American Chemical Society

Functional diversity of 2-oxoglutarate/Fe(II)-dependent dioxygenases in plant metabolism

PubMed Central

Farrow, Scott C.; Facchini, Peter J.

2014-01-01

Oxidative enzymes catalyze many different reactions in plant metabolism. Among this suite of enzymes are the 2-oxoglutarate/Fe(II)-dependent dioxygenases (2-ODDs). Cytochromes P450 (CYPs) as often considered the most versatile oxidative enzymes in nature, but the diversity and complexity of reactions catalyzed by 2-ODDs is superior to the CYPs. The list of oxidative reactions catalyzed by 2-ODDs includes hydroxylations, demethylations, desaturations, ring closure, ring cleavage, epimerization, rearrangement, halogenation, and demethylenation. Furthermore, recent work, including the discovery of 2-ODDs involved in epigenetic regulation, and others catalyzing several characteristic steps in specialized metabolic pathways, support the argument that 2-ODDs are among the most versatile and important oxidizing biological catalysts. In this review, we survey and summarize the pertinent literature with a focus on several key reactions catalyzed by 2-ODDs, and discuss the significance and impact of these enzymes in plant metabolism. PMID:25346740

The Production of Biodiesel from Cottonseed Oil Using Rhizopus oryzae Whole Cell Biocatalysts

NASA Astrophysics Data System (ADS)

Athalye, Sneha Kishor

Biodiesel is an environmentally friendly alternative to fossil fuels which have become increasingly expensive in recent times. An alternate approach to alkaline biodiesel production is needed as catalyst miscibility with the glycerol by-product, generation of large amounts of waste water, and saponification of the feedstock are major disadvantages associated with the process. Lipases are water soluble enzymes which act as catalysts in many lipid based reactions. Reuse of lipases can significantly reduce cost of enzymatic biodiesel production; however retention of lipolytic activity still remains a challenge. Use of microbial cells immobilized on various surfaces like sponge, foam and plastics as biocatalysts instead of extracted enzyme could help overcome this problem. A novel, rigid biomass support with high surface area made from recyclable polyethylene (Bioblok(TM)) was used in this study. Several fungal and bacterial species have been reported to possess appreciable levels of lipase activity. The biomass production and immobilization as well as lipase activity of three different species; Candida rugosa (ATCC #38772), Aspergillus oryzae (ATCC #58299), and Rhizopus oryzae (ATTC #34612) were tested. C. rugosa did not attach well to the support particles while A.oryzae had lower biomass accumulation of 6.1 g (dry cell wt)/L compared to 11.8 g (dry cell wt)/L for R.oryzae. Hence Rhizopus oryzae, fungal specie with cell surface bound lipase was selected for the current study. The study investigated the influence of media composition and growth time of the R.oryzae whole cell biocatalysts, immobilized on the BSPs, for FAME production from cottonseed oil. R.oryzae BSPs grown in basal media supplemented with 1% (w/v) of glucose or oil or both for 48 h, 72 h or 90 h were used in a 36 h transesterification reaction with cottonseed oil and methanol. BSPs grown in both glucose and oil supplemented medium for 72 h had the highest conversion of 22.4% (wt/wt) and a biomass accumulation of 15.6 g (dry cell wt)/L. A reduction in dynamic viscosity of the reaction mixture from 47.3 centipoise to 30.6 centipoise was observed. The impact of moisture addition to the reaction mixture and use of ethanol as acylating agent on R.oryzae BSP fatty acid alkyl ester production was also tested. The presence of 10 wt % moisture in the reaction system had a significant effect (p ≤ 0.05) on the transesterification reaction with ethanol unlike methanol. Fatty acid ethyl ester concentration tripled from 39.3 to 129.1 g/L when moisture was added during transesterification .When oil to acyl acceptor ratio was increased from 1:3 and 1:6 to determine effect of excess alcohol on conversion, an ester conversion of 128.1 g/L for methanol and 129.1 g/L for ethanol were observed. Use of excess amount of acylating agent had a significant adverse effect (p ≤ 0.05) on the overall FAAE production due to deactivation of lipases on contact with large amounts of insoluble alcohol in the oil phase of the reaction. The effect of short chain alcohols on the enzymatic transesterification of cottonseed oil using freeze dried Rhizopus oryzae biomass was examined with and without water addition using methanol, ethanol, 1-Propanol and 1-Butanol at various molar ratios. 1- Butanol in the absence of water resulted in a significantly higher (p . 0.1) conversion of cottonseed oil to 12.5 % fatty acid butyl esters (FABEs). Addition of 10 % water to the reaction mixture significantly reduced (p ≤ 0.1) conversion. No significant difference (p > 0.1) between the conversions was observed for time points after 24 h for a 72 h reaction. 1- Butanol in ratios higher than 3:1 to cottonseed oil had a significant impact (p ≤ 0.1) on conversion. Increasing the amount of biomass used during the reaction lead to significantly higher conversion (p ≤ 0.1). The highest conversion of 27.9 % was observed for the transesterification reaction between cottonseed oil and 1-Butanol, in a 1:6 molar ratio, in the absence of water, when 100 mg of freeze dried R.oryzae biomass was used. The present study concluded that R.oryzae biomass attached better to the Bioblok. material and had highest lipase activity when grown in presence of oil and glucose for 72h. Addition of water to the reaction system gave higher fatty acid alkyl ester conversion when whole immobilized R.oryzae BSPs were used but absence of water promoted conversion with freeze dried biomass.

Copper-Catalyzed Tandem Reactions for Synthesis of Pyrazolo[5,1-a]isoquinolines with Heterocyclic Ketene Aminals as Ligands.

PubMed

Wen, Li-Rong; Jin, Xian-Jun; Niu, Xiao-Dong; Li, Ming

2015-01-02

A CuI-catalyzed tandem reaction of 5-(2-bromoaryl)-N-aryl-1H-pyrazol-3-amines with active acetonitrile derivatives to prepare pyrazolo[5,1-a]isoquinolines in good to excellent yields has been successfully developed under mild conditions with heterocyclic ketene aminals (HKAs) as new ligands. This is the first time HKAs have been used as ligands for copper-catalyzed coupling reactions.

Biodiesel synthesis via transesterification of lipid Chlorophyta cultivated in walne rich carbon medium using KOH/Zeolite catalyst

NASA Astrophysics Data System (ADS)

Dianursanti, Hayati, Siti Zahrotul; Putri, Dwini Normayulisa

2017-11-01

Microalgae from the Chlorophyta division such as Nannochloropsis oculata and Chlorella vulgaris are highly potential to be developed as biodiesel feedstocks because they have a high oil content up to 58%. Biodiesel is produced by transesterification of triglycerides and alcohols with the aid of homogeneous catalysts such as KOH. However, the use of KOH catalysts produces soaps in the biodiesel synthesis. Heterogeneous catalysts are known to solve this problem. One of them is natural zeolite. Zeolite can be used as a catalyst and as a support catalyst. Loading KOH on the zeolite surface is expected to increase alkalinity in KOH/Zeolite catalysts so as to increase the activity of KOH/Zeolite catalyst in transesterification of triglyceride with methanol. In this experimental lipid of microalgae will be used for produced biodiesel via transesterification reaction with methanol and KOH/Zeolite as a catalyst heterogeneous at 60 °C for 3h and utilized catalyst modificated KOH/Zeolite with variation 0.5 M, 1 M and 1.5 M KOH. The modified zeolite was then analyzed by XRF, XRD and BET. The result showed that the yield of biodiesel from lipid N.oculata was 81,09% by 0.5KOH/Zeolite catalyst, 86,53% by 1KOH/Zeolite catalyst, 1,5KOH/Zeolite and 88,13% by 1.5KOH/Zeolit, while the biodiesel produced from lipid C.vulgaris was 59.29% by 0.5KOH/Zeolite, 82.27% by 1KOH/Zeolite and 83.72% by 1.5KOH/Zeolite.

Recent advances in transition metal-catalyzed N -atom transfer reactions of azides

PubMed Central

Driver, Tom G.

2011-01-01

Transition metal-catalyzed N-atom transfer reactions of azides provide efficient ways to construct new carbon–nitrogen and sulfur–nitrogen bonds. These reactions are inherently green: no additive besides catalyst is needed to form the nitrenoid reactive intermediate, and the by-product of the reaction is environmentally benign N2 gas. As such, azides can be useful precursors for transition metal-catalyzed N-atom transfer to sulfides, olefins and C–H bonds. These methods offer competitive selectivities and comparable substrate scope as alternative processes to generate metal nitrenoids. PMID:20617243

Silica, Alumina and Clay Catalyzed Peptide Bond Formation: Enhanced Efficiency of Alumina Catalyst

NASA Astrophysics Data System (ADS)

Bujdák, Juraj; Rode, Bernd M.

1999-10-01

Catalytic efficiencies of clay (hectorite), silica and alumina were tested in peptide bond formation reactions of glycine (Gly), alanine (Ala), proline (Pro), valine (Val) and leucine (Leu). The reactions were performed as drying/wetting (hectorite) and temperature fluctuation (silica and alumina) experiments at 85 °C. The reactivity of amino acids decreased in order Gly > Ala > Pro ~ Val ~ Leu. The highest catalytic efficiency was observed for alumina, the only catalyst producing oligopeptides in all investigated reaction systems. The peptide bond formation on alumina is probably catalyzed by the same sites and via similar reaction mechanisms as some alumina-catalyzed dehydration reactions used in industrial chemistry.

In-Water and Neat Batch and Continuous-Flow Direct Esterification and Transesterification by a Porous Polymeric Acid Catalyst

NASA Astrophysics Data System (ADS)

Baek, Heeyoel; Minakawa, Maki; Yamada, Yoichi M. A.; Han, Jin Wook; Uozumi, Yasuhiro

2016-05-01

A porous phenolsulphonic acid—formaldehyde resin (PAFR) was developed. The heterogeneous catalyst PAFR was applied to the esterification of carboxylic acids and alcohols, affording the carboxylic acid esters in a yield of up to 95% where water was not removed from the reaction mixture. Surprisingly, the esterification in water as a solvent proceeded to afford the desired esters in high yield. PAFR provided the corresponding esters in higher yield than other homogeneous and heterogeneous catalysts. The transesterification of alcohols and esters was also investigated by using PAFR, giving the corresponding esters. PAFR was applied to the batch-wise and continuous-flow production of biodiesel fuel FAME. The PAFR-packed flow reactor that was developed for the synthesis of carboxylic acids and FAME worked for four days without loss of its catalytic activity.

Biodiesel production from heterotrophic microalgal oil.

PubMed

Miao, Xiaoling; Wu, Qingyu

2006-04-01

The present study introduced an integrated method for the production of biodiesel from microalgal oil. Heterotrophic growth of Chlorella protothecoides resulted in the accumulation of high lipid content (55%) in cells. Large amount of microalgal oil was efficiently extracted from these heterotrophic cells by using n-hexane. Biodiesel comparable to conventional diesel was obtained from heterotrophic microalgal oil by acidic transesterification. The best process combination was 100% catalyst quantity (based on oil weight) with 56:1 molar ratio of methanol to oil at temperature of 30 degrees C, which reduced product specific gravity from an initial value of 0.912 to a final value of 0.8637 in about 4h of reaction time. The results suggested that the new process, which combined bioengineering and transesterification, was a feasible and effective method for the production of high quality biodiesel from microalgal oil.

Study of KOH/Al2O3 as heterogeneous catalyst for biodiesel production via in situ transesterification from microalgae.

PubMed

Ma, Guixia; Hu, Wenrong; Pei, Haiyan; Jiang, Liqun; Ji, Yan; Mu, Ruimin

2015-01-01

Heterogeneous KOH/Al2O3 catalysts, synthesized by the wet impregnation method with different KOH loadings (20-40 wt%) and calcination temperatures from 400°C to 800°C, were used to produce biodiesel from Chlorella vulgaris biomass by in situ transesterification. The highest yield of biodiesel of 89.53±1.58% was achieved at calcination temperature of 700°C for 2 h and 35 wt% loading of KOH, and at the optimal reaction condition of 10 wt% of catalyst content, 8 mL/g of methanol to biomass ratio and at 60°C for 5 h. The characteristics of the catalysts were analysed by X-ray diffraction, scanning electron microscopy and Brunauer-Emmett-Teller.

Cu-catalyzed cross-coupling reactions of epoxides with organoboron compounds.

PubMed

Lu, Xiao-Yu; Yang, Chu-Ting; Liu, Jing-Hui; Zhang, Zheng-Qi; Lu, Xi; Lou, Xin; Xiao, Bin; Fu, Yao

2015-02-11

A copper-catalyzed cross-coupling reaction of epoxides with arylboronates is described. This reaction is not limited to aromatic epoxides, because aliphatic epoxides are also suitable substrates. In addition, N-sulfonyl aziridines can be successfully converted into the products. This reaction provides convenient access to β-phenethyl alcohols, which are valuable synthetic intermediates.

Pressure effects on enzyme-catalyzed quantum tunneling events arise from protein-specific structural and dynamic changes.

PubMed

Hay, Sam; Johannissen, Linus O; Hothi, Parvinder; Sutcliffe, Michael J; Scrutton, Nigel S

2012-06-13

The rate and kinetic isotope effect (KIE) on proton transfer during the aromatic amine dehydrogenase-catalyzed reaction with phenylethylamine shows complex pressure and temperature dependences. We are able to rationalize these effects within an environmentally coupled tunneling model based on constant pressure molecular dynamics (MD) simulations. As pressure appears to act anisotropically on the enzyme, perturbation of the reaction coordinate (donor-acceptor compression) is, in this case, marginal. Therefore, while we have previously demonstrated that pressure and temperature dependences can be used to infer H-tunneling and the involvement of promoting vibrations, these effects should not be used in the absence of atomistic insight, as they can vary greatly for different enzymes. We show that a pressure-dependent KIE is not a definitive hallmark of quantum mechanical H-tunneling during an enzyme-catalyzed reaction and that pressure-independent KIEs cannot be used to exclude tunneling contributions or a role for promoting vibrations in the enzyme-catalyzed reaction. We conclude that coupling of MD calculations with experimental rate and KIE studies is required to provide atomistic understanding of pressure effects in enzyme-catalyzed reactions.

Simultaneous production of oil enriched in ω-3 polyunsaturated fatty acids and biodiesel from fish wastes.

PubMed

Enascuta, Cristina Emanuela; Stepan, Emil; Bolocan, Ion; Bombos, Dorin; Calin, Catalina; Oprescu, Elena-Emilia; Lavric, Vasile

2018-05-01

The waste resulted from fish processing industries are discarded into the environment around the world, causing environmental pollution. The main problem of fish oil extracted from waste is the high content in free fatty acids (FFA) which decrease the yield in fatty acids esters during transesterification reactions. Therefore, to correct the fish-oil properties, a new environmentally friendly heterogeneous superacid catalyst (SO 4 2- /SnO 2 -ZrO 2 ) was tested in the esterification reaction of FFA with ethanol. The catalyst was characterized by different techniques (XRD, FT-IR, FT-IR of adsorbed pyridine, BET, SEM-EDX, TGA and acidity measurements). The reaction was found to follow a Langmuir-Hinshelwood (L-H) dual-site mechanism with the novelty that both Brönsted and Lewis acid centers participate equally in the esterification reaction. The pre-treated oil was subjected to transesterification reaction with ethanol over a heterogeneous base catalyst and then, the saturated and unsaturated fractions of fatty acid ethyl esters (FAEE) were separated using a vacuum rectification unit with falling film. The saturated content can be used as biofuel, while the unsaturated FAEE are further transesterified with glycerol in order to obtain oil with high content in polyunsaturated fatty acids (PUFA). A detailed study of the intrinsic kinetic process at the surface of the superacid catalyst and a thorough mathematical model of the fixed bed reactor were written and validated by an experimental program, designed according to the D-optimal methodology. Copyright © 2018 Elsevier Ltd. All rights reserved.

Iron-catalyzed intermolecular cycloaddition of diazo surrogates with hexahydro-1,3,5-triazines.

PubMed

Liu, Pei; Zhu, Chenghao; Xu, Guangyang; Sun, Jiangtao

2017-09-26

We report here an unprecedented iron-catalyzed cycloaddition reaction of diazo surrogates with hexahydro-1,3,5-triazines, providing five-membered heterocycles in moderate to high yields under mild reaction conditions. This cycloaddition features C-N and C-C bond formation using a cheap iron catalyst. Importantly, different to our former report on a gold-catalyzed system, both donor/donor and donor/acceptor diazo substrates are tolerated in this iron-catalyzed protocol.

Copper(II)-Catalyzed Conversion of Aryl/Heteroaryl Boronic Acids, Boronates, and Trifluoroborates into the Corresponding Azides: Substrate Scope and Limitations.

PubMed

Grimes, Kimberly D; Gupte, Amol; Aldrich, Courtney C

2010-05-01

We report the copper(II)-catalyzed conversion of organoboron compounds into the corresponding azide derivatives. A systematic series of phenylboronic acid derivatives is evaluated to examine the importance of steric and electronic effects of the substituents on reaction yield as well as functional group compatibility. Heterocyclic substrates are also shown to participate in this mild reaction while compounds incorporating B-C(sp(3)) bonds are unreactive under the reaction conditions. The copper(II)-catalyzed boronic acid-azide coupling reaction is further extended to both boronate esters and potassium organotrifluoroborate salts. The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and we expect that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the preparation of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3-triazoles derivatives.

Ligand-Controlled Regioselective Copper-Catalyzed Trifluoromethylation To Generate (Trifluoromethyl)allenes.

PubMed

Ambler, Brett R; Peddi, Santosh; Altman, Ryan A

2015-05-15

"Cu-CF3" species have been used historically for a broad spectrum of nucleophilic trifluoromethylation reactions. Although recent advancements have employed ligands to stabilize and harness the reactivity of this key organometallic intermediate, the ability of a ligand to differentiate a regiochemical outcome of a Cu-CF3-mediated or -catalyzed reaction has not been previously reported. Herein, we report the first example of a Cu-catalyzed trifluoromethylation reaction in which a ligand controls the regiochemical outcome. More specifically, we demonstrate the ability of bipyridyl-derived ligands to control the regioselectivity of the Cu-catalyzed nucleophilic trifluoromethylation reactions of propargyl electrophiles to generate (trifluoromethyl)allenes. This method provides a variety of di-, tri-, and tetrasubstituted (trifluoromethyl)allenes, which can be further modified to generate complex fluorinated substructures.

A study on production of biodiesel using a novel solid oxide catalyst derived from waste.

PubMed

Majhi, Samrat; Ray, Srimanta

2016-05-01

The issues of energy security, dwindling supply and inflating price of fossil fuel have shifted the global focus towards fuel of renewable origin. Biodiesel, having renewable origin, has exhibited great potential as substitute for fossil fuels. The most common route of biodiesel production is through transesterification of vegetable oil in presence of homogeneous acid or base or solid oxide catalyst. But, the economics of biodiesel is not competitive with respect to fossil fuel due to high cost of production. The vegetable oil waste is a potential alternative for biodiesel production, particularly when disposal of used vegetable oil has been restricted in several countries. The present study evaluates the efficacy of a low-cost solid oxide catalyst derived from eggshell (a food waste) in transesterification of vegetable oil and simulated waste vegetable oil (SWVO). The impact of thermal treatment of vegetable oil (to simulate frying operation) on transesterification using eggshell-derived solid oxide catalyst (ESSO catalyst) was also evaluated along with the effect of varying reaction parameters. The study reported that around 90 % biodiesel yield was obtained with vegetable oil at methanol/oil molar ratio of 18:1 in 3 h reaction time using 10 % ESSO catalyst. The biodiesel produced with ESSO catalyst from SWVO, thermally treated at 150 °C for 24 h, was found to conform with the biodiesel standard, but the yield was 5 % lower compared to that of the untreated oil. The utilization of waste vegetable oil along with waste eggshell as catalyst is significant for improving the overall economics of the biodiesel in the current market. The utilization of waste for societal benefit with the essence of sustainable development is the novelty of this work.

Thioureas as ligands in the pd-catalyzed intramolecular Pauson-Khand reaction.

PubMed

Tang, Yefeng; Deng, Lujiang; Zhang, Yangdong; Dong, Guangbin; Chen, Jiahua; Yang, Zhen

2005-04-14

[reaction: see text] The thiourea-Pd complex was established as a novel type of catalyst in the PKR of allylpropargylamine, and the demonstrated chemistry may prove to be valuable for developing thiuorea as a ligand for the Pd-catalyzed Pauson-Khand reaction.

Kinetics of the Reaction Between Alcohols and Isocyanates Catalyzed by Ferric Acetylacetonate

NASA Technical Reports Server (NTRS)

Schieler, Leroy

1961-01-01

The rate and temperature dependence of reaction for the ferric acetylacetonate catalyzed reaction between a-naphthyl, ortho-tolyl, and para-tolyl isocyanates and n-butyl alcohol are investigated. The effect of substituents on the reactivity of isocyanate and hydroxyl group are reported and for substituted isocyanates are correlated by means of the Hammett equation. Several metal chelates were studied and their catalytic activity was compared to that of ferric acetylacetonate. All rate data are interpreted in terms of a mechanism involving simultaneous second-order uncatalyzed and catalyzed reactions between alcohol and isocyanate.

Diastereo- and enantioselective iridium-catalyzed allylation of cyclic ketone enolates: synergetic effect of ligands and barium enolates.

PubMed

Chen, Wenyong; Chen, Ming; Hartwig, John F

2014-11-12

We report asymmetric allylic alkylation of barium enolates of cyclic ketones catalyzed by a metallacyclic iridium complex containing a phosphoramidite ligand derived from (R)-1-(2-naphthyl)ethylamine. The reaction products contain adjacent quaternary and tertiary stereocenters. This process demonstrates that unstabilized cyclic ketone enolates can undergo diastereo- and enantioselective Ir-catalyzed allylic substitution reactions with the proper choice of enolate countercation. The products of these reactions can be conveniently transformed to various useful polycarbocyclic structures.

Synthesis of isocoumarins through three-component couplings of arynes, terminal alkynes, and carbon dioxide catalyzed by an NHC-copper complex.

PubMed

Yoo, Woo-Jin; Nguyen, Thanh V Q; Kobayashi, Shū

2014-09-15

A copper-catalyzed multicomponent coupling reaction between in situ generated ortho-arynes, terminal alkynes, and carbon dioxide was developed to access isocoumarins in moderate to good yields. The key to this CO2-incorporating reaction was the use of a versatile N-heterocyclic carbene/copper complex that was able to catalyze multiple transformations within the three-component reaction. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Copper-catalyzed domino reactions for the synthesis of cyclic compounds.

PubMed

Liao, Qian; Yang, Xianghua; Xi, Chanjuan

2014-09-19

Copper-catalyzed domino reactions are one of the most useful strategies for the construction of various cyclic compounds. In this Synopsis, we mainly focus on the latest advances in copper-catalyzed cross-coupling or addition-initiated domino reactions in the synthesis of cyclic compounds, including double alkenylation of N- or S-nucleophiles, alkenylation or alkynlation followed by cyclization of amides or amines, addition and cyclization of heteroallenes affording heterocycles, and coupling and cyclization of 1,3-dicarbonyl compounds toward heterocycles.

Diastereo- and enantioselective iridium-catalyzed allylation of cyclic ketone enolates: Synergetic effect of ligands and barium enolates

DOE PAGES

Chen, Wenyong; Chen, Ming; Hartwig, John F.

2014-10-22

Here, we report asymmetric allylic alkylation of barium enolates of cyclic ketones catalyzed by a metallacyclic iridium complex containing a phosphoramidite ligand derived from ( R)-1-(2-naphthyl)ethylamine. The reaction products contain adjacent quaternary and tertiary stereocenters. This process demonstrates that unstabilized cyclic ketone enolates can undergo diastereo- and enantioselective Ir-catalyzed allylic substitution reactions with the proper choice of enolate countercation. The products of these reactions can be conveniently transformed to various useful polycarbocyclic structures.

Quantum chemical studies of a model for peptide bond formation. 3. Role of magnesium cation in formation of amide and water from ammonia and glycine

NASA Technical Reports Server (NTRS)

Oie, T.; Loew, G. H.; Burt, S. K.; MacElroy, R. D.

1984-01-01

The SN2 reaction between glycine and ammonia molecules with magnesium cation Mg2+ as a catalyst has been studied as a model reaction for Mg(2+)-catalyzed peptide bond formation using the ab initio Hartree-Fock molecular orbital method. As in previous studies of the uncatalyzed and amine-catalyzed reactions between glycine and ammonia, two reaction mechanisms have been examined, i.e., a two-step and a concerted reaction. The stationary points of each reaction including intermediate and transition states have been identified and free energies calculated for all geometry-optimized reaction species to determine the thermodynamics and kinetics of each reaction. Substantial decreases in free energies of activation were found for both reaction mechanisms in the Mg(2+)-catalyzed amide bond formation compared with those in the uncatalyzed and amine-catalyzed amide bond formation. The catalytic effect of the Mg2+ cation is to stabilize both the transition states and intermediate, and it is attributed to the neutralization of the developing negative charge on the electrophile and formation of a conformationally flexible nonplanar five-membered chelate ring structure.

Copper-Catalyzed SN2'-Selective Allylic Substitution Reaction of gem-Diborylalkanes.

PubMed

Zhang, Zhen-Qi; Zhang, Ben; Lu, Xi; Liu, Jing-Hui; Lu, Xiao-Yu; Xiao, Bin; Fu, Yao

2016-03-04

A Cu/(NHC)-catalyzed SN2'-selective substitution reaction of allylic electrophiles with gem-diborylalkanes is reported. Different substituted gem-diborylalkanes and allylic electrophiles can be employed in this reaction, and various synthetic valuable functional groups can be tolerated. The asymmetric version of this reaction was initially researched with chiral N-heterocyclic carbene (NHC) ligands.

Copper-catalyzed oxidative Heck reactions between alkyltrifluoroborates and vinyl arenes.

PubMed

Liwosz, Timothy W; Chemler, Sherry R

2013-06-21

We report herein that potassium alkyltrifluoroborates can be utilized in oxidative Heck-type reactions with vinyl arenes. The reaction is catalyzed by a Cu(OTf)2/1,10-phenanthroline with MnO2 as the stoichiometric oxidant. In addition to the alkyl Heck, amination, esterification, and dimerization reactions of alkyltrifluoroborates are demonstrated under analogous reaction conditions. Evidence for an alkyl radical intermediate is presented.

Gold-Catalyzed Formal C-C Bond Insertion Reaction of 2-Aryl-2-diazoesters with 1,3-Diketones.

PubMed

Ren, Yuan-Yuan; Chen, Mo; Li, Ke; Zhu, Shou-Fei

2018-06-29

The transition-metal-catalyzed formal C-C bond insertion reaction of diazo compounds with monocarbonyl compounds is well established, but the related reaction of 1,3-diketones instead gives C-H bond insertion products. Herein, we report a protocol for a gold-catalyzed formal C-C bond insertion reaction of 2-aryl-2-diazoesters with 1,3-diketones, which provides efficient access to polycarbonyl compounds with an all-carbon quaternary center. The aryl ester moiety plays a crucial role in the unusual chemoselectivity, and the addition of a Brønsted acid to the reaction mixture improves the yield of the C-C bond insertion product. A reaction mechanism involving cyclopropanation of a gold carbenoid with an enolate and ring-opening of the resulting donor-acceptor-type cyclopropane intermediate is proposed. This mechanism differs from that of the traditional Lewis-acid-catalyzed C-C bond insertion reaction of diazo compounds with monocarbonyl compounds, which involves a rearrangement of a zwitterion intermediate as a key step. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Production of Mahua Oil Ethyl Ester (MOEE) and its Performance test on four stroke single cylinder VCR engine

NASA Astrophysics Data System (ADS)

Soudagar, Manzoor Elahi M.; Kittur, Prasanna; Parmar, Fulchand; Batakatti, Sachin; Kulkarni, Prasad; Kallannavar, Vinayak

2017-08-01

Biodiesel is a substitute for gasoline that is produced from vegetable oils and animal fats. It has gained popularity due to depleting fossil fuel resources, its renewable character and comparable combustion properties to diesel fuel. Biodiesel is formed from non-edible oils, edible oils, tallow, animal fats and waste cooked oils. Biodiesels are monoalkyl esters of elongated chain fatty acids. Biodiesel can be a viable choice for satisfying long term energy requirements if they are managed proficiently. The method of the transesterification shows how the reaction occurs and advances. In this study, biodiesel is produced from Madhuca indica seeds commonly known as Mahua by using transesterification process using a low capacity pressure reactor and by-product of transesterification is glycerol, which is used in preparation of soaps. Mahua Oil Ethyl Ester (MOEE) was produced from the Mahua oil and is mixed with diesel to get different ratios of blends. MOEE was tested in a 4-stroke single cylinder VCR diesel engine. The study was extended to understand the effect of biodiesel blend magnitude on the performance of engine parameters like, brake thermal efficiency, brake power and fuel properties like flash point, cloud point, kinematic viscosity, calorific value, cetane number and density were studied.

Identification and electrophysiological studies of (4 S,5 S)-5-hydroxy-4-methyl-3-heptanone and 4-methyl-3,5-heptanedione in male lucerne weevils

NASA Astrophysics Data System (ADS)

Unelius, C. R.; Park, K.-C.; McNeill, M.; Wee, S. L.; Bohman, B.; Suckling, D. M.

2013-02-01

An investigation to identify a sex or aggregation pheromone of Sitona discoideus Gyllenhål (Coleoptera: Curculionidae) is presented. Antenna flicking and attraction behaviors evoked by conspecifics of both sexes were recorded in arena bioassays, where attraction of females to males was observed. Air entrainment of both males and females was conducted in separate chambers. Gas chromatographic-mass spectrometric analysis of headspace volatiles revealed that two male-specific compounds, 4-methyl-3,5-heptanedione (major) and (4 S,5 S)-5-hydroxy-4-methyl-3-heptanone (minor), were emitted during the autumnal post-aestivatory flight period. The stereoisomers of the minor component were separated by enantioselective gas chromatography and their absolute configurations assigned by NMR (diastereomers) and the known preference of enantioselective transesterification reactions catalyzed by Candida antarctica lipase B. Electroantennogram and single sensillum recording studies indicate that 4-methyl-3,5-heptanedione as well as all individual stereoisomers of 5-hydroxy-4-methyl-3-heptanone are detected by the antennae of male and female S. discoideus. Further, single sensillum recordings suggest that both sexes of S. discoideus have specialized olfactory receptor neurons (ORNs) for detecting 4-methyl-3,5-heptanedione and different populations of stereoselective ORNs for detecting the stereoisomers of 5-hydroxy-4-methyl-3-heptanone. Some of these stereoselective ORNs appear to be sex-specific in S. discoideus.

Immobilization of Yarrowia lipolytica Lipase on Macroporous Resin Using Different Methods: Characterization of the Biocatalysts in Hydrolysis Reaction.

PubMed

Sun, Jingjing; Chen, Yiling; Sheng, Jun; Sun, Mi

2015-01-01

To improve the reusability and organic solvent tolerance of microbial lipase and expand the application of lipase (hydrolysis, esterification, and transesterification), we immobilized marine microbial lipase using different methods and determined the properties of immobilized lipases. Considering the activity and cost of immobilized lipase, the concentration of lipase was fixed at 2 mg/mL. The optimal temperature of immobilized lipases was 40°C and 5°C higher than free lipase. The activities of immobilized lipases were much higher than free lipase at alkaline pH (more than 50% at pH 12). The free lipase lost most activity (35.3%) and immobilized lipases retained more than 46.4% of their initial activity after 3 h heat treatment at 70°C. At alkaline pH, immobilized lipases were more stable than free lipase (more than 60% residue activity at pH 11 for 3 h). Immobilized lipases retained 80% of their activity after 5 cycles and increased enzyme activity (more than 108.7%) after 3 h treatment in tert-butanol. Immobilization of lipase which improved reusability of lipase and provided a chance to expand the application of marine microbial lipase in organic system expanded the application range of lipase to catalyze hydrolysis and esterification in harsh condition.

Spectroscopic Investigation of the Electrosynthesis of Diphenyl Carbonate from CO and Phenol on Gold Electrodes

PubMed Central

2018-01-01

In this work, we study the synthesis of diphenyl carbonate (DPC) from phenol and CO on gold electrodes studied by means of in situ Fourier transform infrared spectroscopy (FTIR). The results show that, on gold electrodes, the formation of DPC is observed at potentials as low as 0.4 V vs Ag/AgCl, together with the formation of dimethyl carbonate (DMC) from the carbonylation of methanol that was used as a solvent. The spectroelectrochemical results also suggest that the formation of DPC occurs via the replacement of the methoxy groups from DMC with phenoxy groups from phenol and not directly by the carbonylation of phenol. Although this transesterification process is known to occur with heterogeneous catalysts, it has not been reported under electrochemical conditions. These are interesting findings, since the direct DPC production by carbonylation of phenol to DPC is usually performed with Pd-based catalysts. With this reaction scheme of transesterification happening under electrochemical conditions, other non-Pd catalysts could be used as well for one-step DPC production from phenol and CO. These findings give important mechanistic insights into this reaction and open up possibilities to an alternative process for the production of DPC. PMID:29657886

Investigation of acyl migration in mono- and dicaffeoylquinic acids under aqueous basic, aqueous acidic, and dry roasting conditions.

PubMed

Deshpande, Sagar; Jaiswal, Rakesh; Matei, Marius Febi; Kuhnert, Nikolai

2014-09-17

Acyl migration in chlorogenic acids describes the process of migration of cinnamoyl moieties from one quinic acid alcohol group to another, thus interconverting chlorogenic acid regioisomers. It therefore constitutes a special case of transesterification reaction. Acyl migration constitutes an important reaction pathway in both coffee roasting and brewing, altering the structure of chlorogenic acid initially present in the green coffee bean. In this contribution we describe detailed and comprehensive mechanistic studies comparing inter- and intramolecular acyl migration involving the seven most common chlorogenic acids in coffee. We employe aqueous acidic and basic conditions mimicking the brewing of coffee along with dry roasting conditions. We show that under aqueous basic conditions intramolecular acyl migration is fully reversible with basic hydrolysis competing with acyl migration. 3-Caffeoylquinic acid was shown to be most labile to basic hydrolysis. We additionally show that the acyl migration process is strongly pH dependent with increased transesterification taking place at basic pH. Under dry roasting conditions acyl migration competes with dehydration to form lactones. We argue that acyl migration precedes lactonization, with 3-caffeoylquinic acid lactone being the predominant product.

Metal-catalyzed Decarboxylative Fluoroalkylation Reactions.

PubMed

Ambler, Brett R; Yang, Ming-Hsiu; Altman, Ryan A

2016-12-01

Metal-catalyzed decarboxylative fluoroalkylation reactions enable the conversion of simple O-based substrates into biologically relevant fluorinated analogs. Herein, we present decarboxylative methods that facilitate the synthesis of trifluoromethyl- and difluoroketone-containing products. We highlight key mechanistic aspects that are critical for efficient catalysis, and that inspired our thinking while developing the reactions.

Computational Elucidation of Selectivities and Mechanisms Performed by Organometallic and Bioinorganic Catalysts

NASA Astrophysics Data System (ADS)

Grandner, Jessica Marie

Computational methods were used to determine the mechanisms and selectivities of organometallic-catalyzed reactions. The first half of the dissertation focuses on the study of metathesis catalysts in collaboration with the Grubbs group at CalTech. Chapter 1 describes the studies of the decomposition modes of several ruthenium-based metathesis catalysts. These studies were performed to better understand the decomposition of such catalysts in order to prevent decomposition (Chapter 1.2) or utilize decomposed catalysts for alternative reactions (Chapter 1.1). Chapter 2.1 describes the computational investigation of the origins of stereoretentive metathesis with ruthenium-based metathesis catalysts. These findings were then used to computationally design E-selective metathesis catalysts (Chapter 2.2). While the first half of the dissertation was centered around ruthenium catalysts, the second half of the dissertation pertains to iron-catalyzed reaction, in particular, iron-catalyzed reactions by P450 enzymes. The elements of Chapter 3 concentrate on the stereo- and chemo-selectivity of P450-catalyzed C-H hydroxylations. By combining multiple computational methods, the inherent activity of the iron-oxo catalyst and the influence of the active site on such reactions were illuminated. These discoveries allow for the engineering of new substrates and mutant enzymes for tailored C-H hydroxylation. While the mechanism of C-H hydroxylations catalyzed by P450 enzymes has been well studied, there are several P450-catalyzed transformations for which the mechanism is unknown. The components of Chapter 4 describe the use of computations to determine the mechanisms of complex, multi-step reactions catalyzed by P450s. The determination of these mechanisms elucidates how these enzymes react with various functional groups and substrate architectures and allows for a better understanding of how drug-like compounds may be broken down by human P450s.

Base catalyzed synthesis of bicyclo[3.2.1]octane scaffolds.

PubMed

Boehringer, Régis; Geoffroy, Philippe; Miesch, Michel

2015-07-07

The base-catalyzed reaction of achiral 1,3-cyclopentanediones tethered to activated olefins afforded in high yields bicyclo[3.2.1]octane-6,8-dione or bicyclo[3.2.1]octane-6-carboxylate derivatives bearing respectively three or five stereogenic centers. The course of the reaction is closely related to the reaction time and to the base involved in the reaction.

Protease activation in glycerol-based deep eutectic solvents.

PubMed

Zhao, Hua; Baker, Gary A; Holmes, Shaletha

2011-11-01

Deep eutectic solvents (DESs) consisting of mixtures of a choline salt (chloride or acetate form) and glycerol are prepared as easily accessible, biodegradable, and inexpensive alternatives to conventional aprotic cation-anion paired ionic liquids. These DES systems display excellent fluidity coupled with thermal stability to nearly 200 °C. In this work, the transesterification activities of cross-linked proteases (subtilisin and α-chymotrypsin), immobilized on chitosan, were individually examined in these novel DESs. In the 1:2 molar ratio mixture of choline chloride/glycerol containing 3% (v/v) water, cross-linked subtilisin exhibited an excellent activity (2.9 μmo l min(-1) g(-1)) in conjunction with a selectivity of 98% in the transesterification reaction of N-acetyl-L-phenylalanine ethyl ester with 1-propanol. These highly encouraging results advocate more extensive exploration of DESs in protease-mediated biotransformations of additional polar substrates and use of DESs in biocatalysis more generally.

Synthesis of fatty acid methyl ester from palm oil (Elaeis guineensis) with Ky(MgCa)2xO3 as heterogeneous catalyst.

PubMed

Olutoye, M A; Lee, S C; Hameed, B H

2011-12-01

Fatty acid methyl esters (FAME) were produced from palm oil using eggshell modified with magnesium and potassium nitrates to form a composite, low-cost heterogeneous catalyst for transesterification. The catalyst, prepared by the combination of impregnation/co-precipitation was calcined at 830 °C for 4 h. Transesterification was conducted at a constant temperature of 65 °C in a batch reactor. Design of experiment (DOE) was used to optimize the reaction parameters, and the conditions that gave highest yield of FAME (85.8%) was 5.35 wt.% catalyst loading at 4.5 h with 16:1 methanol/oil molar ratio. The results revealed that eggshell, a solid waste, can be utilized as low-cost catalyst after modification with magnesium and potassium nitrates for biodiesel production. Copyright © 2011 Elsevier Ltd. All rights reserved.

In-Water and Neat Batch and Continuous-Flow Direct Esterification and Transesterification by a Porous Polymeric Acid Catalyst

PubMed Central

Baek, Heeyoel; Minakawa, Maki; Yamada, Yoichi M. A.; Han, Jin Wook; Uozumi, Yasuhiro

2016-01-01

A porous phenolsulphonic acid—formaldehyde resin (PAFR) was developed. The heterogeneous catalyst PAFR was applied to the esterification of carboxylic acids and alcohols, affording the carboxylic acid esters in a yield of up to 95% where water was not removed from the reaction mixture. Surprisingly, the esterification in water as a solvent proceeded to afford the desired esters in high yield. PAFR provided the corresponding esters in higher yield than other homogeneous and heterogeneous catalysts. The transesterification of alcohols and esters was also investigated by using PAFR, giving the corresponding esters. PAFR was applied to the batch-wise and continuous-flow production of biodiesel fuel FAME. The PAFR-packed flow reactor that was developed for the synthesis of carboxylic acids and FAME worked for four days without loss of its catalytic activity. PMID:27189631

Subcritical ethylic biodiesel production from wet animal fat and vegetable oils: A net energy ratio analysis

DOE PAGES

Sales, Emerson A.; Ghirardi, Maria L.; Jorquera, Orlando

2016-08-23

Ethylic transesterification process for biodiesel production without any chemical or biochemical catalysts at different subcritical thermodynamic conditions was performed using wet animal fat, soybean and palm oils as feedstock. The results indicate that 2 h of reaction at 240 °C with pressures varying from 20 to 45 bar was sufficient to transform almost all lipid fraction of the samples to biodiesel, depending on the reactor dead volume and proportions between reactants. Conversions of 100%, 84% and 98.5% were obtained for animal fat, soybean oil and palm oil, respectively, in the presence of water, with a net energy ration values ofmore » 2.6, 2.1 and 2.5 respectively. Finally, these results indicate that the process is energetically favorable, and thus represents a cleaner technology with environmental advantages when compared to traditional esterification or transesterification processes.« less

Subcritical ethylic biodiesel production from wet animal fat and vegetable oils: A net energy ratio analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sales, Emerson A.; Ghirardi, Maria L.; Jorquera, Orlando

Ethylic transesterification process for biodiesel production without any chemical or biochemical catalysts at different subcritical thermodynamic conditions was performed using wet animal fat, soybean and palm oils as feedstock. The results indicate that 2 h of reaction at 240 °C with pressures varying from 20 to 45 bar was sufficient to transform almost all lipid fraction of the samples to biodiesel, depending on the reactor dead volume and proportions between reactants. Conversions of 100%, 84% and 98.5% were obtained for animal fat, soybean oil and palm oil, respectively, in the presence of water, with a net energy ration values ofmore » 2.6, 2.1 and 2.5 respectively. Finally, these results indicate that the process is energetically favorable, and thus represents a cleaner technology with environmental advantages when compared to traditional esterification or transesterification processes.« less

Ultrasonic assisted biodiesel production of microalgae by direct transesterification

NASA Astrophysics Data System (ADS)

Kalsum, Ummu; Mahfud, Mahfud; Roesyadi, Achmad

2017-03-01

Microalgae are considered as the third generation source of biofuel and an excellent candidate for biofuel production to replace the fossil energy. The use of ultrasonic in producing biodiesel by direct transesterification of Nannochloropsis occulata using KOH as catalyst and methanol as a solvent was investigated. The following condition were determined as an optimum by experimental evaluates:: 1: 15 microalga to methanol (molar ratio); 3% catalyst concentration at temperature 40°C after 30 minute of ultrasonication. The highest yield of biodiesel produced was 30.3%. The main components of methyl ester from Nannochloropsis occulata were palmitic (C16 :0),, oleic (C18:1), stearic (C18;0), arahidic (C20:0) and myristic (C14:0). This stated that the application of ultrasounic for direct transesterificaiton of microalgae effectively reduced the reaction time compared to the reported values of conventional heating systems.

Biodiesel production from palm oil using calcined waste animal bone as catalyst.

PubMed

Obadiah, Asir; Swaroopa, Gnanadurai Ajji; Kumar, Samuel Vasanth; Jeganathan, Kenthorai Raman; Ramasubbu, Alagunambi

2012-07-01

Waste animal bones was employed as a cost effective catalyst for the transesterification of palm oil. The catalyst was calcined at different temperatures to transform the calcium phosphate in the bones to hydroxyapatite and 800 °C was found to give the best yield of biodiesel. The catalyst was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometry (EDS) and Fourier transform infrared spectrometry (FT-IR). Under the optimal reaction conditions of 20 wt.% of catalyst, 1:18 oil to methanol molar ratio, 200 rpm of stirring of reactants and at a temperature of 65 °C, the methyl ester conversion was 96.78% and it was achieved in 4h. The catalyst performed equally well as the laboratory-grade CaO. Animal bone is therefore a useful raw material for the production of a cheap catalyst for transesterification. Copyright © 2012 Elsevier Ltd. All rights reserved.

Scale-up of industrial biodiesel production to 40 m(3) using a liquid lipase formulation.

PubMed

Price, Jason; Nordblad, Mathias; Martel, Hannah H; Chrabas, Brent; Wang, Huali; Nielsen, Per Munk; Woodley, John M

2016-08-01

In this work, we demonstrate the scale-up from an 80 L fed-batch scale to 40 m(3) along with the design of a 4 m(3) continuous process for enzymatic biodiesel production catalyzed by NS-40116 (a liquid formulation of a modified Thermomyces lanuginosus lipase). Based on the analysis of actual pilot plant data for the transesterification of used cooking oil and brown grease, we propose a method applying first order integral analysis to fed-batch data based on either the bound glycerol or free fatty acid content in the oil. This method greatly simplifies the modeling process and gives an indication of the effect of mixing at the various scales (80 L to 40 m(3) ) along with the prediction of the residence time needed to reach a desired conversion in a CSTR. Suitable process metrics reflecting commercial performance such as the reaction time, enzyme efficiency, and reactor productivity were evaluated for both the fed-batch and CSTR cases. Given similar operating conditions, the CSTR operation on average, has a reaction time which is 1.3 times greater than the fed-batch operation. We also showed how the process metrics can be used to quickly estimate the selling price of the enzyme. Assuming a biodiesel selling price of 0.6 USD/kg and a one-time use of the enzyme (0.1% (w/woil ) enzyme dosage); the enzyme can then be sold for 30 USD/kg which ensures that that the enzyme cost is not more than 5% of the biodiesel revenue. Biotechnol. Bioeng. 2016;113: 1719-1728. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Gold-nanoparticle-catalyzed synthesis of propargylamines: the traditional A3-multicomponent reaction performed as a two-step flow process.

PubMed

Abahmane, Lahbib; Köhler, J Michael; Gross, G Alexander

2011-03-01

The alkyne, aldehyde, amine A(3)-coupling reaction, a traditional multicomponent reaction (MCR), has been investigated as a two-step flow process. The implicated aminoalkylation reaction of phenylacetylene with appropriate aldimine intermediates was catalyzed by gold nanoparticles impregnated on alumina. The aldimine formation was catalyzed by Montmorillonite K10 beforehand. The performance of the process has been investigated with respect to different reaction regimes. Usually, the A(3)-multicomponent reaction is performed as a "one-pot" process. Diversity-oriented syntheses using MCRs often have the shortcoming that only low selectivity and low yields are achieved. We have used a flow-chemistry approach to perform the A(3)-MCR in a sequential manner. In this way, the reaction performance was significantly enhanced in terms of shortened reaction time, and the desired propargylamines were obtained in high yields. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

1,1,1-tris(hydroxymethyl)ethane as a new, efficient, and versatile tripod ligand for copper-catalyzed cross-coupling reactions of aryl iodides with amides, thiols, and phenols.

PubMed

Chen, Yao-Jung; Chen, Hsin-Hung

2006-11-23

1,1,1-tris(hydroxymethyl)ethane was presented as a new, efficient, and versatile tridentate O-donor ligand suitable for the copper-catalyzed formation of C-N, C-S, and C-O bonds. This inexpensive and commercially available tripod ligand has been demonstrated to facilitate the copper-catalyzed cross-coupling reactions of aryl iodides with amides, thiols, and phenols to afford the corresponding desired products in good to excellent yields. [reaction: see text].

Formation of polycyclic lactones through a ruthenium-catalyzed ring-closing metathesis/hetero-Pauson-Khand reaction sequence.

PubMed

Finnegan, David F; Snapper, Marc L

2011-05-20

Processes that form multiple carbon-carbon bonds in one operation can generate molecular complexity quickly and therefore be used to shorten syntheses of desirable molecules. We selected the hetero-Pauson-Khand (HPK) cycloaddition and ring-closing metathesis (RCM) as two unique carbon-carbon bond-forming reactions that could be united in a tandem ruthenium-catalyzed process. In doing so, complex polycyclic products can be obtained in one reaction vessel from acyclic precursors using a single ruthenium additive that can catalyze sequentially two mechanistically distinct transformations.

N-heterocyclic carbene-catalyzed tandem aza-benzoin/Michael reactions: on site reversal of the reactivity of N-Boc imines.

PubMed

Wu, Ke-Jia; Li, Gong-Qiang; Li, Yi; Dai, Li-Xin; You, Shu-Li

2011-01-07

A tandem NHC-catalyzed aza-benzoin/Michael reaction has been developed as a method to efficiently produce dihydroindenones and pyrrolidinone-containing tricycles. The novel reaction pattern involves tert-butyl aryl(tosyl)methylcarbamates reacting as both electrophile and nucleophile on the same carbon.

Regioselective and enantiospecific rhodium-catalyzed allylic alkylation reactions using copper(I) enolates: synthesis of (-)-sugiresinol dimethyl ether.

PubMed

Evans, P Andrew; Leahy, David K

2003-07-30

The transition metal-catalyzed allylic alkylation represents a fundamentally important cross-coupling reaction for the construction of ternary carbon stereogenic centers. We have developed a regioselective and enantiospecific rhodium-catalyzed allylic alkylation of acyclic unsymmetrical allylic alcohol derivatives using copper(I) enolates to prepare beta-substituted ketones. This protocol represents a convenient asymmetric Claisen rearrangement surrogate in which alpha-substituted enolates permit the introduction of an additional stereogenic center. The synthetic utility of this transformation was highlighted in the construction of a trans-1,2-disubstituted cyclohexene and the total synthesis of (-)-sugiresinol dimethyl ether. Finally, we anticipate that copper(I) enolates may prove useful nucleophiles in related metal-catalyzed reactions.

A cis-prenyltransferase from Methanosarcina acetivorans catalyzes both head-to-tail and nonhead-to-tail prenyl condensation.

PubMed

Ogawa, Takuya; Emi, Koh-Ichi; Koga, Kazushi; Yoshimura, Tohru; Hemmi, Hisashi

2016-06-01

Cis-prenyltransferase usually consecutively catalyzes the head-to-tail condensation reactions of isopentenyl diphosphate to allylic prenyl diphosphate in the production of (E,Z-mixed) polyprenyl diphosphate, which is the precursor of glycosyl carrier lipids. Some recently discovered homologs of the enzyme, however, catalyze the nonhead-to-tail condensation reactions between allylic prenyl diphosphates. In this study, we characterize a cis-prenyltransferase homolog from a methanogenic archaeon, Methanosarcina acetivorans, to obtain information on the biosynthesis of the glycosyl carrier lipids within it. This enzyme catalyzes both head-to-tail and nonhead-to-tail condensation reactions. The kinetic analysis shows that the main reaction of the enzyme is consecutive head-to-tail prenyl condensation reactions yielding polyprenyl diphosphates, while the chain lengths of the major products seem shorter than expected for the precursor of glycosyl carrier lipids. On the other hand, a subsidiary reaction of the enzyme, i.e., nonhead-to-tail condensation between dimethylallyl diphosphate and farnesyl diphosphate, gives a novel diterpenoid compound, geranyllavandulyl diphosphate. © 2016 Federation of European Biochemical Societies.

Continuous In Vitro Evolution of a Ribozyme that Catalyzes Three Successive Nucleotidyl Addition Reactions

NASA Technical Reports Server (NTRS)

McGinness, Kathleen E.; Wright, Martin C.; Joyce, Gerald F.

2002-01-01

Variants of the class I ligase ribozyme, which catalyzes joining of the 3' end of a template bound oligonucleotide to its own 5' end, have been made to evolve in a continuous manner by a simple serial transfer procedure that can be carried out indefinitely. This process was expanded to allow the evolution of ribozymes that catalyze three successive nucleotidyl addition reactions, two template-directed mononucleotide additions followed by RNA ligation. During the development of this behavior, a population of ribozymes was maintained against an overall dilution of more than 10(exp 406). The resulting ribozymes were capable of catalyzing the three-step reaction pathway, with nucleotide addition occurring in either a 5' yieldig 3' or a 3' yielding 5' direction. This purely chemical system provides a functional model of a multi-step reaction pathway that is undergoing Darwinian evolution.

Copper-catalyzed oxidative homo- and cross-coupling of Grignard reagents using diaziridinone.

PubMed

Zhu, Yingguang; Xiong, Tao; Han, Wenyong; Shi, Yian

2014-12-05

Transition-metal-catalyzed cross-coupling reactions are among the most powerful synthetic transformations. This paper describes an efficient copper-catalyzed homo- and cross-coupling of Grignard reagents with di-tert-butyldiaziridinone as oxidant under mild conditions, giving the coupling products in good to excellent yields. The reaction process has a broad substrate scope and is also effective for the C(sp)-C(sp(3)) coupling.

Theoretical studies on the Mo-catalyzed asymmetric intramolecular Pauson-Khand-type [2+2+1] cycloadditions of 3-allyloxy-1-propynylphosphonates.

PubMed

Meng, Qingxi; Li, Ming

2012-08-01

Density functional theory (DFT) was used to investigate the Mo-catalyzed intramolecular Pauson-Khand reaction of 3-allyloxy-1-propynylphosphonates. All intermediates and transition states were optimized completely at the B3LYP/6-31 G(d,p) level [LANL2DZ(f) for Mo]. In the Mo-catalyzed intramolecular Pauson-Khand reaction, the C–C oxidative cyclization reaction was the chirality-determining step, and the reductive elimination reaction was the rate-determining step. The carbonyl insertion reaction into the Mo–C(sp(3)) bondwas easier than into the Mo–C=C bond. And the dominant product predicted theoretically was of (S)-chirality, which agreed with experimental data. This reaction was solventd ependent, and toluene was the best among the three solvents toluene, CH3CN, and THF.

Applications of Palladium-Catalyzed C-N Cross-Coupling Reactions.

PubMed

Ruiz-Castillo, Paula; Buchwald, Stephen L

2016-10-12

Pd-catalyzed cross-coupling reactions that form C-N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C-N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts.

Applications of Palladium-Catalyzed C–N Cross-Coupling Reactions

PubMed Central

2016-01-01

Pd-catalyzed cross-coupling reactions that form C–N bonds have become useful methods to synthesize anilines and aniline derivatives, an important class of compounds throughout chemical research. A key factor in the widespread adoption of these methods has been the continued development of reliable and versatile catalysts that function under operationally simple, user-friendly conditions. This review provides an overview of Pd-catalyzed N-arylation reactions found in both basic and applied chemical research from 2008 to the present. Selected examples of C–N cross-coupling reactions between nine classes of nitrogen-based coupling partners and (pseudo)aryl halides are described for the synthesis of heterocycles, medicinally relevant compounds, natural products, organic materials, and catalysts. PMID:27689804

Studies on the oxidation reaction of tyrosine (Tyr) with H2O2 catalyzed by horseradish peroxidase (HRP) in alcohol-water medium by spectrofluorimetry and differential spectrophotometry.

PubMed

Tang, Bo; Wang, Yan; Liang, Huiling; Chen, Zhenzhen; He, Xiwen; Shen, Hanxi

2006-03-01

An oxidation reaction of tyrosine (Tyr) with H(2)O(2) catalyzed by horseradish peroxidase (HRP) was studied by spectrofluorimetry and differential spectrophotometry in the alcohol(methanol, ethanol, 1-propanol and isopropanol)-water mutual solubility system. Compared with the enzymatic-catalyzed reaction in the water medium, the fluorescence intensities of the product weakened, even extinguished. Because the addition of alcohols made the conformation of HRP change, the catalytic reaction shifted to the side of polymerization and the polymer (A(n)H(2), n>or=3) exhibited no fluorescence. The four alcohols cannot deactivate HRP. Moreover isopropanol activated HRP remarkably.

Kinetic Parameters for the Noncatalyzed and Enzyme-Catalyzed Mutarotation of Glucose Using a Blood Glucometer

ERIC Educational Resources Information Center

Hardee, John R.; Delgado, Bryan; Jones, Wray

2011-01-01

The kinetic parameters for the conversion of alpha-D-glucose to beta-D-glucose were measured using a blood glucometer. The reaction order, rate constant, and Arrhenius activation energy are reported for the noncatalyzed reaction and turnover number and Michaelis constant are reported for the reaction catalyzed by porcine kidney mutarotase. The…

The rhodium catalyzed three-component reaction of diazoacetates, titanium(IV) alkoxides and aldehydes.

PubMed

Lu, Chong-Dao; Liu, Hui; Chen, Zhi-Yong; Hu, Wen-Hao; Mi, Ai-Qiao

2005-05-28

The rhodium(II)-catalyzed three-component reaction of diazoacetates, titanium alkoxides and aldehydes is shown to give alpha-alkoxyl-beta-hydroxyl acid derivatives; the novel C-C bond formation reaction is proposed to occur through oxonium ylides derived from diazo compounds and titanium alkoxides, and followed by intermolecular trapping by aldehydes.

Construction of Benzene Rings by Copper-Catalyzed Cycloaddition Reactions of Oximes and Maleimides: An Access to Fused Phthalimides.

PubMed

Yang, Jie; Zhao, Bo; Xi, Yue; Sun, Si; Yang, Zhen; Ye, Ying; Jiang, Kun; Wei, Ye

2018-02-16

A useful Cu-catalyzed cycloaddition protocol for the construction of benzene rings has been achieved. The reactions, utilizing readily available oximes and maleimides as starting materials, proceed under mild reaction conditions to generate a series of structurally interesting fused-phthalimides that are difficult to be prepared by conventional methods.

Recent Development in Chemical Depolymerization of Lignin: A Review

DOE PAGES

Wang, Hai; Tucker, Melvin; Ji, Yun

2013-01-01

This article reviewed recent development of chemical depolymerization of lignins. There were five types of treatment discussed, including base-catalyzed, acid-catalyzed, metallic catalyzed, ionic liquids-assisted, and supercritical fluids-assisted lignin depolymerizations. The methods employed in this research were described, and the important results were marked. Generally, base-catalyzed and acid-catalyzed methods were straightforward, but the selectivity was low. The severe reaction conditions (high pressure, high temperature, and extreme pH) resulted in requirement of specially designed reactors, which led to high costs of facility and handling. Ionic liquids, and supercritical fluids-assisted lignin depolymerizations had high selectivity, but the high costs of ionic liquids recyclingmore » and supercritical fluid facility limited their applications on commercial scale biomass treatment. Metallic catalyzed depolymerization had great advantages because of its high selectivity to certain monomeric compounds and much milder reaction condition than base-catalyzed or acid-catalyzed depolymerizations. It would be a great contribution to lignin conversion if appropriate catalysts were synthesized.« less

Copper-Catalyzed Oxidative Reaction of β-Keto Sulfones with Alcohols via C-S Bond Cleavage: Reaction Development and Mechanism Study.

PubMed

Du, Bingnan; Wang, Wenmin; Wang, Yang; Qi, Zhenghang; Tian, Jiaqi; Zhou, Jie; Wang, Xiaochen; Han, Jianlin; Ma, Jing; Pan, Yi

2018-02-16

A Cu-catalyzed cascade oxidative radical process of β-keto sulfones with alcohols has been achieved by using oxygen as an oxidant. In this reaction, β-keto sulfones were converted into sulfinate esters under the oxidative conditions via cleavage of C-S bond. Experimental and computational studies demonstrate that a new pathway is involved in this reaction, which proceeds through the formation of the key four-coordinated Cu II intermediate, O-O bond homolysis induced C-S bond cleavage and Cu-catalyzed esterification to form the final products. This reaction provides a new strategy to sulfonate esters and enriches the research content of C-S bond cleavage and transformations. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Method for converting UF5 to UF4 in a molten fluoride salt

DOEpatents

Bennett, Melvin R.; Bamberger, Carlos E.; Kelmers, A. Donald

1977-01-01

The reduction of UF.sub.5 to UF.sub.4 in a molten fluoride salt by sparging with hydrogen is catalyzed by metallic platinum. The reaction is also catalyzed by platinum alloyed with gold reaction equipment.

The Phase Behavior Effect on the Reaction Engineering of Transesterification Reactions and Reactor Design for Continuous Biodiesel Production

NASA Astrophysics Data System (ADS)

Csernica, Stephen N.

The demand for renewable forms of energy has increased tremendously over the past two decades. Of all the different forms of renewable energy, biodiesel, a liquid fuel, has emerged as one of the more viable possibilities. This is in large part due to the fact that biodiesel can readily be used in modern day diesel engines with nearly no engine modifications. It is commonly blended with conventional petroleum-derived diesel but it can also be used neat. As a result of the continued growth of the industry, there has been a correspondingly large increase in the scientific and technical research conducted on the subject. Much of the research has been conducted on the feasibility of using different types of feedstocks, which generally vary with respect to geographic locale, as well as different types of catalysts. Much of the work of the present study was involved with the investigation of the binary liquid-liquid nature of the system and its effects on the reaction kinetics. Initially, the development of an analytical method for the analysis of the compounds present in transesterification reaction mixtures using high performance liquid chromatography (HPLC) was developed. The use of UV(205 nm) as well as refractive index detection (RID) were shown capable to detect the various different types of components associated with transesterification reactions. Reversed-phase chromatography with isocratic elution was primarily used. Using a unique experimental apparatus enabling the simultaneous analysis of both liquid phases throughout the reaction, an experimental method was developed for measuring the reaction rate under both mass transfer control and reaction control. The transesterification reaction rate under each controlling mechanism was subsequently evaluated and compared. It was determined that the reaction rate is directly proportional to the concentration of triglycerides in the methanol phase. Furthermore, the reaction rate accelerates rapidly as the system transitions from two phases to a single phase, or pseudo-single phase. The transition to a single phase or pseudo-single phase is a function of the methanol content. Regardless, the maximum observed reaction rate occurs at the point of the phase transition, when the concentration of triglycerides in the methanol phase is largest. The phase transition occurs due to the accumulation of the primary product, biodiesel methyl esters. Through various experiments, it was determined that the rate of the triglyceride mass transfer into the methanol phase, as well as the solubility of triglycerides in methanol, increases with increasing methyl ester concentration. Thus, there exists some critical methyl ester concentration which favors the formation of a single or pseudo-single phase system. The effect of the by-product glycerol on the reaction kinetics was also investigated. It was determined that at low methanol to triglyceride molar ratios, glycerol acts to inhibit the reaction rate and limit the overall triglyceride conversion. This occurs because glycerol accumulates in the methanol phase, i.e. the primary reaction volume. When glycerol is at relatively high concentrations within the methanol phase, triglycerides become excluded from the reaction volume. This greatly reduces the reaction rate and limits the overall conversion. As the concentration of methanol is increased, glycerol becomes diluted and the inhibitory effects become dampened. Assuming pseudo-homogeneous phase behavior, a simple kinetic model incorporating the inhibitory effects of glycerol was proposed based on batch reactor data. The kinetic model was primarily used to theoretically compare the performance of different types of continuous flow reactors for continuous biodiesel production. It was determined that the inhibitory effects of glycerol result in the requirement of very large reactor volumes when using continuous stirred tank reactors (CSTR). The reactor volume can be greatly reduced using tubular style plug flow reactors (PFR). Despite this fact, the use of CSTRs is more common than the use of PFRs. This is mostly due to the fact that the two initial reactant phases are relatively immiscible and significant agitation is generally supplied to initiate the reaction. Based on the theoretical results, however, the use of a packed-bed tubular flow reactor was investigated experimentally. A series of two tubular flow reactors was built in the laboratory. The first reactor was of the shell and tube variety and also functioned as a preheater. The second reactor was larger and contained a packed-bed. Two different flow configurations were invested, upflow-upflow and downflow-downflow. It was determined that the downflow-downflow configuration provided significantly better triglyceride conversions that the upflow-upflow configuration.

Copper-Catalyzed Oxidative Homo- and Cross-Coupling of Grignard Reagents Using Diaziridinone

PubMed Central

2015-01-01

Transition-metal-catalyzed cross-coupling reactions are among the most powerful synthetic transformations. This paper describes an efficient copper-catalyzed homo- and cross-coupling of Grignard reagents with di-tert-butyldiaziridinone as oxidant under mild conditions, giving the coupling products in good to excellent yields. The reaction process has a broad substrate scope and is also effective for the C(sp)–C(sp3) coupling. PMID:25420218

Effect of Lanthanum-Natural Zeolite, La/NZA catalyst on biodiesel production from crude palm oil

NASA Astrophysics Data System (ADS)

Setianingsih, A.; Wisrayetti; Khairat; Bahri, S.

2018-04-01

Biodiesel can be produced from vegetable oils through the trans-esterification process. In this study, potential vegetable oil of Crude Palm Oil (CPO) was used as sample. The purposes of this research were to produce biodiesel from CPO as an alternative fuel, having study the ratio of impregnation of Lanthanum on NZA, and its catalyst weight to the biodiesel yield. The La/NZA catalyst is made as followed, first the natural zeolite size was reduced using grinding, then activated using HCl 6 N and NH4Cl 1 N, followed with the drying process. La is impregnated into NZA as solution having variations of 1 and 3% (w/w) of NZA, then it was followed with dried in an oven, calcination, oxidation and reduction. Production of biodiesel is carried out through two stages of esterification and transesterification processes. In the trans-esterification process conducted with the various variation of catalyst weight i.e. 1, 2 and 3% of La/NZA (w/w) for a total weight of 80 grams of CPO sample, having the ratio of oil : methanol 1 : 9. Reaction was lasted for 60 minutes at 60°C having 400 rpm stirring speed. From the result, the conversion of 85.37% is given by the run on using 3% La/NZA catalyst having catalyst weight 1%.

Green Reductive Homocoupling of Bromobenzene

ERIC Educational Resources Information Center

Ballard, C. Eric

2011-01-01

Although transition-metal-catalyzed reactions are important in contemporary organic chemistry, relatively few resources for the second-year organic chemistry curriculum discuss the subject. The inquiry-based experiment described here, an iron-catalyzed preparation of biphenyl from bromobenzene, introduces this topic. The reaction uses an…

Synthesis of disulfides and diselenides by copper-catalyzed coupling reactions in water.

PubMed

Li, Zhengkai; Ke, Fang; Deng, Hang; Xu, Hualong; Xiang, Haifeng; Zhou, Xiangge

2013-05-14

A simple and efficient protocol for copper-catalyzed coupling reactions between aryl halides and elemental sulfur or selenium has been developed. A variety of disulfides and diselenides can be obtained in moderate to excellent yields up to 96%.

Chemoselective N-heterocyclic carbene-catalyzed cross-benzoin reactions: importance of the fused ring in triazolium salts.

PubMed

Langdon, Steven M; Wilde, Myron M D; Thai, Karen; Gravel, Michel

2014-05-28

Morpholinone- and piperidinone-derived triazolium salts are shown to catalyze highly chemoselective cross-benzoin reactions between aliphatic and aromatic aldehydes. The reaction scope includes ortho-, meta-, and para-substituted benzaldehyde derivatives with a range of electron-donating and -withdrawing groups as well as branched and unbranched aliphatic aldehydes. Catalytic loadings as low as 5 mol % give excellent yields in these reactions (up to 99%).

Iron-catalyzed cross-coupling of imidoyl chlorides with Grignard reagents.

PubMed

Ottesen, Lars K; Ek, Fredrik; Olsson, Roger

2006-04-27

[reaction: see text] A general, high yielding rapid iron-catalyzed cross-coupling reaction between Grignard reagents and imidoyl chlorides is described. These reactions are typically completed within 5 min, resulting in high yields of 71-96% using 5% iron catalyst in a THF-NMP solvent mixture. Functionalized imidoyl chlorides (e.g., R = CO(2)Me) gave excellent yields (89%).

Copper-catalyzed tandem reactions of 1-(2-iodoary)-2-yn-1-ones with isocyanides for the synthesis of 4-oxo-indeno[1,2-b]pyrroles.

PubMed

Cai, Qian; Zhou, Fengtao; Xu, Tianfeng; Fu, Liangbing; Ding, Ke

2011-01-21

A novel copper-catalyzed tandem reaction of 1-(2-iodoaryl)-2-yn-1-ones with isocyanides is described. The reaction is through a formal [3 + 2] cycloaddition/coupling tandem process and leads to efficient formation of 4-oxo-indeno[1,2-b]pyrroles.

Copper-catalyzed cross-coupling reactions of epoxides with gem-diborylmethane: access to γ-hydroxyl boronic esters.

PubMed

Ebrahim-Alkhalil, Ahmed; Zhang, Zhen-Qi; Gong, Tian-Jun; Su, Wei; Lu, Xiao-Yu; Xiao, Bin; Fu, Yao

2016-04-07

Herein, we describe a novel copper-catalyzed epoxide opening reaction with gem-diborylmethane. Aliphatic, aromatic epoxides as well as aziridines are converted to the corresponding γ-pinacolboronate alcohols or amines in moderate to excellent yields. This new reaction provides beneficial applications for classic epoxide substrates as well as interesting gem-diborylalkane reagents.

All kinds of reactivity: recent breakthroughs in metal-catalyzed alkyne chemistry.

PubMed

Anaya de Parrodi, Cecilia; Walsh, Patrick J

2009-01-01

Alkynes of reactions: Recent breakthroughs in metal-catalyzed alkyne reactions, which expand the synthetic utility of alkynes, have been achieved. These approaches broaden the range of alkynes that are accessible by C--N and C--C bond-forming reactions and demonstrate that the use of bifunctional heterobimetallic catalysts can lead to new reactivity and excellent enantioselectivity (see scheme).

Study of the techniques feasible for food synthesis aboard a spacecraft

NASA Technical Reports Server (NTRS)

Weiss, A. H.

1972-01-01

Synthesis of sugars by Ca(OH)2 catalyzed formaldehyde condensation (the formose reaction) has produced branched carbohydrates that do not occur in nature. The kinetics and mechanisms of the homogeneously catalyzed autocatalytic condensation were studied and analogies between homogeneous and heterogeneous rate laws have been found. Aldol condensations proceed simultaneously with Cannizzaro and crossed-Cannizzaro reactions and Lobry de Bruyn-Van Eckenstein rearrangements. The separate steps as well as the interactions of this highly complex reaction system were elucidated. The system exhibits instabilities, competitive catalytic, mass action, and equilibrium phenomena, complexing, and parallel and consecutive reactions. Specific finding that have been made on the problem will be of interest for synthesizing sugars, both for sustained space flight and for large scale food manufacture. A contribution to methodology for studying complex catalyzed reactions and to understanding control of reaction selectivity was a broad goal of the project.

Desaturation reactions catalyzed by soluble methane monooxygenase.

PubMed

Jin, Y; Lipscomb, J D

2001-09-01

Soluble methane monooxygenase (MMO) is shown to be capable of catalyzing desaturation reactions in addition to the usual hydroxylation and epoxidation reactions. Dehydrogenated products are generated from MMO-catalyzed oxidation of certain substrates including ethylbenzene and cyclohexadienes. In the reaction of ethylbenzene, desaturation of ethyl C-H occurred along with the conventional hydroxvlations of ethyl and phenyl C-Hs. As a result, styrene is formed together with ethylphenols and phenylethanols. Similarly, when 1,3- and 1,4-cyclohexadienes were used as substrates, benzene was detected as a product in addition to the corresponding alcohols and epoxides. In all cases, reaction conditions were found to significantly affect the distribution among the different products. This new activity of MMO is postulated to be associated with the chemical properties of the substrates rather than fundamental changes in the nature of the oxygen and C-H activation chemistries. The formation of the desaturated products is rationalized by formation of a substrate cationic intermediate, possibly via a radical precursor. The cationic species is then proposed to partition between recombination (alcohol formation) and elimination (alkene production) pathways. This novel function of MMO indicates close mechanistic kinship between the hydroxylation and desaturation reactions catalyzed by the nonheme diiron clusters.

Rh-Catalyzed Annulations of N-Methoxybenzamides and Ketenimines: Sterically and Electronically Controlled Synthesis of Isoquinolinones and Isoindolinones.

PubMed

Zhou, Xiaorong; Zhang, Zhiyin; Zhao, Hongyang; Lu, Ping; Wang, Yanguang

2017-04-07

Rhodium-catalyzed C-H activation/annulation reactions of ketenimines with N-methoxybenzamides are reported. The outcome of reactions is dependent on the structure of ketenimines. The β-alkyl-substituted ketenimines furnish 3-iminoisoquinolin-1(2H)-ones in a formal [4 + 2] annulation manner, while the β-ester substituted ketenimines afford 3-aminoisoindolin-1-ones in a formal [4 + 1] annulation manner. The synthesized [4 + 2] products undergo an intramolecular Cu-catalyzed C-N coupling to be converted to benzo[4,5]imidazo[1,2-b]isoquinolin-11-ones, which can be directly prepared from ketenimines and N-methoxybenzamides by a one-pot Rh-catalyzed annulation/Cu-catalyzed C-N coupling sequence.

Effect of Hydrothermal Treatment on Structural and Catalytic Properties of [CTA]-MCM-41 Silica.

PubMed

Zapelini, Iago W; Silva, Laura L; Cardoso, Dilson

2018-05-21

The [CTA]-MCM-41 hybrid silica is a useful and simply prepared heterogeneous basic catalyst for the transesterification reaction. Here, the effect of hydrothermal treatment during catalyst preparation was investigated, with the aim of improving the structural stability of this catalyst during the reaction. It was observed that the hydrothermal step led to the formation of a material with a higher degree of organization and a greater wall thickness, which improved its structural stability. However, the catalyst prepared using this treatment presented lower catalytic activity, due to the presence of fewer active sites.

Expanding P450 catalytic reaction space through evolution and engineering

PubMed Central

McIntosh, John A.; Farwell, Christopher C.; Arnold, Frances H.

2014-01-01

Advances in protein and metabolic engineering have led to wider use of enzymes to synthesize important molecules. However, many desirable transformations are not catalyzed by any known enzyme, driving interest in understanding how new enzymes can be created. The cytochrome P450 enzyme family, whose members participate in xenobiotic metabolism and natural products biosynthesis, catalyzes an impressive range of difficult chemical reactions that continues to grow as new enzymes are characterized. Recent work has revealed that P450-derived enzymes can also catalyze useful reactions previously accessible only to synthetic chemistry. The evolution and engineering of these enzymes provides an excellent case study for how to genetically encode new chemistry and expand biology’s reaction space. PMID:24658056

Alkanes from Bioderived Furans by using Metal Triflates and Palladium-Catalyzed Hydrodeoxygenation of Cyclic Ethers.

PubMed

Song, Hai-Jie; Deng, Jin; Cui, Min-Shu; Li, Xing-Long; Liu, Xin-Xin; Zhu, Rui; Wu, Wei-Peng; Fu, Yao

2015-12-21

Using a metal triflate and Pd/C as catalysts, alkanes were prepared from bioderived furans in a one-pot hydrodeoxygenation (HDO) process. During the reaction, the metal triflate plays a crucial role in the ring-opening HDO of furan compounds. The entire reaction process has goes through two major phases: at low temperatures, saturation of the exocyclic double bond and furan ring are catalyzed by Pd/C; at high temperatures, the HDO of saturated furan compounds is catalyzed by the metal triflate. The reaction mechanism was verified by analyzing the changes of the intermediates during the reaction. In addition, different metal triflates, solvents, and catalyst recycling were also investigated. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Gold(I)-catalyzed tandem cyclization approach to tetracyclic indolines.

PubMed

Liu, Yongxiang; Xu, Wenqing; Wang, Xiang

2010-04-02

Two highly stereoselective cationic gold(I)-catalyzed tandem cyclization reactions of alkynylindoles are described. These reactions demonstrated a novel and general strategy to rapidly construct highly functionalized polycyclic indolines. This approach was successfully employed for a formal synthesis of the akuammiline alkaloid minfiensine.

PALLADIUM-CATALYZED OXIDATION OF STYRENE AND ALKENES IN PRESENCE OF IONIC LIQUIDS (WACKER REACTION)

EPA Science Inventory

The use of ionic liquids in various synthetic transformations is gaining significance due to the enhanced reaction rates, potential for recycling and compatibility with various organic compounds and organometallic catalysts. Palladium-catalyzed oxidation of styrene and other alk...

Catalytic total hydrodeoxygenation of biomass-derived polyfunctionalized substrates to alkanes.

PubMed

Nakagawa, Yoshinao; Liu, Sibao; Tamura, Masazumi; Tomishige, Keiichi

2015-04-13

The total hydrodeoxygenation of carbohydrate-derived molecules to alkanes, a key reaction in the production of biofuel, was reviewed from the aspect of catalysis. Noble metals (or Ni) and acid are the main components of the catalysts, and group 6 or 7 metals such as Re are sometimes added as modifiers of the noble metal. The main reaction route is acid-catalyzed dehydration plus metal-catalyzed hydrogenation, and in some systems metal-catalyzed direct CO dissociation is involved. The appropriate active metal, acid strength, and reaction conditions depend strongly on the reactivity of the substrate. Reactions that use Pt or Pd catalysts supported on Nb-based acids or relatively weak acids are suitable for furanic substrates. Carbohydrates themselves and sugar alcohols undergo CC dissociation easily. The systems that use metal-catalyzed direct CO dissociations can give a higher yield of the corresponding alkane from carbohydrates and sugar alcohols. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Theoretical Study of the Effects of Di-Muonic Molecules on Muon-Catalyzed Fusion

DTIC Science & Technology

2012-03-01

For example, synthetic zeolites could be used to separate molecular isotopes of hydrogen [12; 10] as could thermal diffusion and gas chromatography... thermal muon flux is large (see Chapter 8). Reactions which have the potential of increasing the muon-catalyzed fusion rate and reactions that could...the remainder of this document. Changes to the muon-catalyzed fusion cycle, that are expected to occur when the thermal muon flux is high, are

Intramolecular Benzoin Reaction Catalyzed by Benzaldehyde Lyase from Pseudomonas Fluorescens Biovar I.

PubMed

Hernández, Karel; Parella, Teodor; Petrillo, Giovanna; Usón, Isabel; Wandtke, Claudia M; Joglar, Jesús; Bujons, Jordi; Clapés, Pere

2017-05-02

Intramolecular benzoin reactions catalyzed by benzaldehyde lyase from Pseudomonas fluorescens biovar I (BAL) are reported. The structure of the substrates envisaged for this reaction consists of two benzaldehyde derivatives linked by an alkyl chain. The structural requirements needed to achieve the intramolecular carbon-carbon bond reaction catalyzed by BAL were established. Thus, a linker consisting of a linear alkyl chain of three carbon atoms connected through ether-type bonds to the 2 and 2' positions of two benzaldehyde moieties, which could be substituted with either Cl, Br, or OCH 3 at either the 3 and 3' or 5 and 5' positions, were suitable substrates for BAL. Reactions with 61-84 % yields of the intramolecular product and ee values between 64 and 98 %, were achieved. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transesterification process to manufacture ethyl ester of rape oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Korus, R.A.; Hoffman, D.S.; Bam, N.

1993-12-31

A process for the production of the ethyl ester of winter rape [EEWR] for use as a biodiesel fuel has been studied. The essential part of the process is the transesterification of rape oil with ethanol, in the presence of a catalyst, to yield the ethyl ester of rape oil as a product and glycerin as a by-product. Experiments have been performed to determine the optimum conditions for the preparation of EEWR. The process variables were: (1) temperature, (2) catalyst, (3) rate of agitation, (4) water content of the alcohol used, and (5) the amount of excess alcohol used. Themore » optimum conditions were: (1) room temperature, (2) 0.5% sodium methoxide or 1% potassium hydroxide catalyst by weight of rapeseed oil, (3) extremely vigorous agitation with some splashing during the initial phase of the reaction and agitation was not necessary after the reaction mixture became homogeneous, (4) absolute ethanol was necessary for high conversion, and (5) 50% excess ethanol with NaOCH{sub 3} or 100% excess with KOH gave a maximum conversion. Viscosity, cloud point and pour point of the EEWR were measured. A preliminary break-even cost for the commercial production of EEWR was found to be $0.55/liter [$2.08/US gallon].« less

Data on PKO biodiesel production using CaO catalyst from Turkey bones.

PubMed

Ayoola, A A; Fayomi, O S I; Usoro, I F

2018-08-01

In this research paper the production of biodiesel from palm kernel oil (PKO) using CaO obtained from waste turkey bones (WTB) and analytical grade calcium oxide was investigated. Treated WTB was reduced to fine particulate size of <150 µm and then calcinated at 800 °C for 3 h to increase its catalytic activity by its conversion from Calcium phosphate hydroxide (Ca 10 P 6 O 26 H 2 ) to CaO. X-ray diffraction (XRD) and X-ray fluorescent (XRF) analysis of the analytical grade CaO, uncalcined and calcined WTB were carried out to establish their elemental chemical composition. The transesterification reaction between the triglyceride of palm kernel oil (PKO) and methanol was carried out at a constant agitation speed of 600 rpm and temperature of 65 °C, with varied methanol to oil molar ratio (8-14), catalyst concentration (1-7 wt/wt%) and the reaction time (1-3 h). Minitab 17 software (using response surface method) was employed for the design of experiment and statistical analysis required in the transesterification process of biodiesel production. The qualities of the biodiesel produced were assessed and the results obtained showed conformity of the biodiesel produced to the ASTM standard for biodiesel.

Effect of one step KOH activation and CaO modified carbon in transesterification reaction

NASA Astrophysics Data System (ADS)

Yacob, Abd Rahim; Zaki, Muhammad Azam Muhammad

2017-11-01

In this work, one step activation was introduced using potassium hydroxide (KOH) and calcium oxide (CaO) modified palm kernel shells. Various concentration of calcium oxide was used as catalyst while maintaining the same concentration of potassium hydroxide to activate and impregnate the palm kernel shell before calcined at 500°C for 5 hours. All the prepared samples were characterized using Fourier Transform Infrared (FTIR) and Field Emission Scanning Electron Microscope (FESEM). FTIR analysis of raw palm kernel shell showed the presence of various functional groups. However, after activation, most of the functional groups were eliminated. The basic strength of the prepared samples were determined using back titration method. The samples were then used as base heterogeneous catalyst for the transesterification reaction of rice bran oil with methanol. Analysis of the products were performed using Gas Chromatography Flame Ionization Detector (GC-FID) to calculate the percentage conversion of the biodiesel products. This study shows, as the percentage of one step activation potassium and calcium oxide doped carbon increases thus, the basic strength also increases followed by the increase in biodiesel production. Optimization study shows that the optimum biodiesel production was at 8 wt% catalyst loading, 9:1 methanol: oil molar ratio at 65°C and 6 hours which gives a conversion up to 95%.

Formation of ethyl ferulate from feruloylated oligosaccharide by transesterification of rice koji enzyme under sake mash conditions.

PubMed

Suzuki, Nobukazu; Ito, Toshihiko; Hiroshima, Kai; Tokiwano, Tetsuo; Hashizume, Katsumi

2016-03-01

Formation of ethyl ferulate (EF) and ferulic acid (FA) under sake mash conditions was studied using feruloylated oligosaccharide (FO), prepared from rice grains, as the substrate for rice koji enzyme. EF and FA were produced from FO over six times faster than from alkyl ferulates however, under the same ethanol concentration, only small differences were observed between the EF/FA ratios when either FO or methyl ferulate were used as substrates. Esterification and hydrolysis of FO or methyl ferulate showed similar pH dependencies and similar EF/FA ratios for each substrate in all of the pH ranges tested. Ethanol concentration clearly affected the EF/FA ratio; the ratio increased as ethanol concentration increased. Formation of EF and FA in the sake mash simulated rice digest was accelerated by addition of exogenous FO. These results indicated that supply of FO to sake mash is a crucial step for EF and FA formation, and ethanol is an influencing factor in the EF/FA ratio. The rice koji enzyme reaction suggested that EF and FA are formed through a common feruloylated enzyme intermediate complex by transesterification or hydrolysis, and these reactions occur competitively. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Solvent-dependent reactions for the synthesis of β-keto-benzo-δ-sultone scaffolds via DBU-catalyzed O-sulfonylation/intramolecular Baylis-Hillman/1,3-H shift or dehydration tandem sequences.

PubMed

Ghandi, Mehdi; Bozcheloei, Abolfazl Hasani; Nazari, Seyed Hadi; Sadeghzadeh, Masoud

2011-12-16

We have developed a solvent-dependent method for the synthesis of novel benzo-δ-sultone scaffolds. A variety of benzylbenzo[e][1,2]oxathiin-4(3H)-one-2,2-dioxides were obtained in high yields in DMF using a one-pot, DBU-catalyzed condensation of 2-hydroxybenzaldehydes with a number of (E)-2-phenylethenesulfonyl chlorides. On the other hand, the initially prepared 2-formylphenyl-(E)-2-phenylethenesulfonate derivatives underwent DBU-catalyzed reactions to a series of 3-[methoxy(phenyl)methyl]benzo[e][1,2]oxathiine-2,2-dioxides in moderate to good yields in MeOH. These reactions presumably proceed via DBU-catalyzed O-sulfonylation/intramolecular Baylis-Hillman/1,3-H shift or dehydration tandem sequences, respectively.

Rh(I)-catalyzed [(3 + 2) + 1] cycloaddition of 1-yne/ene-vinylcyclopropanes and CO: homologous Pauson-Khand reaction and total synthesis of (+/-)-alpha-agarofuran.

PubMed

Jiao, Lei; Lin, Mu; Zhuo, Lian-Gang; Yu, Zhi-Xiang

2010-06-04

A novel Rh(I)-catalyzed [(3 + 2) + 1] cycloaddition, which can be regarded as a homologous Pauson-Khand reaction, was developed to synthesize bicyclic cyclohexenones and cyclohexanones, enabling a new approach for synthesis of six-membered carbocycles ubiquitously found in natural products and pharmaceutics. The significance of the Rh-catalyzed [(3 + 2) + 1] cycloaddition has been demonstrated by the total synthesis of a furanoid sesquiterpene natural product, alpha-agarofuran, in which the bicyclic skeleton was constructed by the [(3 + 2) + 1] reaction of 1-yne-VCP and CO.

Water Oxidation by a Cytochrome P450: Mechanism and Function of the Reaction

PubMed Central

Prasad, Brinda; Mah, Derrick J.; Lewis, Andrew R.; Plettner, Erika

2013-01-01

P450cam (CYP101A1) is a bacterial monooxygenase that is known to catalyze the oxidation of camphor, the first committed step in camphor degradation, with simultaneous reduction of oxygen (O2). We report that P450cam catalysis is controlled by oxygen levels: at high O2 concentration, P450cam catalyzes the known oxidation reaction, whereas at low O2 concentration the enzyme catalyzes the reduction of camphor to borneol. We confirmed, using 17O and 2H NMR, that the hydrogen atom added to camphor comes from water, which is oxidized to hydrogen peroxide (H2O2). This is the first time a cytochrome P450 has been observed to catalyze oxidation of water to H2O2, a difficult reaction to catalyze due to its high barrier. The reduction of camphor and simultaneous oxidation of water are likely catalyzed by the iron-oxo intermediate of P450cam, and we present a plausible mechanism that accounts for the 1∶1 borneol:H2O2 stoichiometry we observed. This reaction has an adaptive value to bacteria that express this camphor catabolism pathway, which requires O2, for two reasons: 1) the borneol and H2O2 mixture generated is toxic to other bacteria and 2) borneol down-regulates the expression of P450cam and its electron transfer partners. Since the reaction described here only occurs under low O2 conditions, the down-regulation only occurs when O2 is scarce. PMID:23634216

Initiator and Photocatalyst-Free Visible Light Induced One-Pot Reaction: Concurrent RAFT Polymerization and CuAAC Click Reaction.

PubMed

Wang, Jie; Wang, Xinbo; Xue, Wentao; Chen, Gaojian; Zhang, Weidong; Zhu, Xiulin

2016-05-01

A new, visible light-catalyzed, one-pot and one-step reaction is successfully employed to design well-controlled side-chain functionalized polymers, by the combination of ambient temperature revisible addtion-fragmentation chain transfer (RAFT) polymerization and click chemistry. Polymerizations are well controlled in a living way under the irradiation of visible light-emitting diode (LED) light without photocatalyst and initiator, using the trithiocarbonate agent as iniferter (initiator-transfer agent-terminator) agent at ambient temperature. Fourier transfer infrared spectroscopy (FT-IR), NMR, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) data confirm the successful one-pot reaction. Compared to the reported zero-valent metal-catalyzed one-pot reaction, the polymerization rate is much faster than that of the click reaction, and the visible light-catalyzed one-pot reaction can be freely and easily regulated by turning on and off the light. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Palladium-catalyzed domino C,N-coupling/carbonylation/Suzuki coupling reaction: an efficient synthesis of 2-aroyl-/heteroaroylindoles.

PubMed

Arthuis, Martin; Pontikis, Renée; Florent, Jean-Claude

2009-10-15

A convenient one-pot synthesis of 2-aroylindoles using a domino palladium-catalyzed C,N-coupling/carbonylation/C,C-coupling sequence is described. The reaction involved easily prepared 2-gem-dibromovinylanilines and boronic acids under carbon monoxide. Optimized reaction conditions allowed the construction of a wide variety of highly functionalized 2-aroyl-/heteroaroylindoles in satisfactory yields.

Room-temperature Pd-catalyzed C-H chlorination by weak coordination: one-pot synthesis of 2-chlorophenols with excellent regioselectivity.

PubMed

Sun, Xiuyun; Sun, Yonghui; Zhang, Chao; Rao, Yu

2014-02-07

A room-temperature Pd(II)-catalyzed regioselective chlorination reaction has been developed for a facile one-pot synthesis of a broad range of 2-chlorophenols. The reaction demonstrates an excellent regioselectivity and reactivity for C-H chlorination. This reaction represents one of the rare examples of mild C-H functionalization at ambient temperature.

Computationally designed and experimentally confirmed diastereoselective rhodium-catalyzed Pauson-Khand reaction at room temperature.

PubMed

Baik, Mu-Hyun; Mazumder, Shivnath; Ricci, Paolo; Sawyer, James R; Song, Ye-Geun; Wang, Huijun; Evans, P Andrew

2011-05-25

The computational analysis of the rhodium-catalyzed Pauson-Khand reaction indicates that the key transition state is highly charge-polarized, wherein different diastereoisomers have distinctively different charge polarization patterns. Experimental studies demonstrate that chloro-enynes provide the optimal σ-electron-withdrawing group to promote polarization and thereby reduce the activation barrier to provide a highly diastereoselective reaction at room temperature.

Aryl Ketone Synthesis via Tandem Orthoplatinated Triarylphosphite-Catalyzed Addition Reactions of Arylboronic Acids with Aldehydes Followed by Oxidation

PubMed Central

Liao, Yuan-Xi; Hu, Qiao-Sheng

2010-01-01

Tandem orthoplatinated triarylphosphite-catalyzed addition reactions of arylboronic acids with aldehydes followed by oxidation to yield aryl ketones is described. 3-Pentanone was identified as a suitable oxidant for the tandem aryl ketone formation reaction. By using microwave energy, aryl ketones were obtained in high yields with the catalyst loading as low as 0.01%. PMID:20849092

Nafion®-catalyzed microwave-assisted Ritter reaction: An atom-economic solvent-free synthesis of amides

EPA Science Inventory

An atom-economic solvent-free synthesis of amides by the Ritter reaction of alcohols and nitriles under microwave irradiation is reported. This green protocol is catalyzed by solid supported Nafion®NR50 with improved efficiency and reduced waste production.

Method to upgrade bio-oils to fuel and bio-crude

DOEpatents

Steele, Philip H; Pittman, Jr., Charles U; Ingram, Jr., Leonard L; Gajjela, Sanjeev; Zhang, Zhijun; Bhattacharya, Priyanka

2013-12-10

This invention relates to a method and device to produce esterified, olefinated/esterified, or thermochemolytic reacted bio-oils as fuels. The olefinated/esterified product may be utilized as a biocrude for input to a refinery, either alone or in combination with petroleum crude oils. The bio-oil esterification reaction is catalyzed by addition of alcohol and acid catalyst. The olefination/esterification reaction is catalyzed by addition of resin acid or other heterogeneous catalyst to catalyze olefins added to previously etherified bio-oil; the olefins and alcohol may also be simultaneously combined and catalyzed by addition of resin acid or other heterogeneous catalyst to produce the olefinated/esterified product.

RNA-Catalyzed RNA Ligation on an External RNA Template

NASA Technical Reports Server (NTRS)

McGinness, Kathleen E.; Joyce, Gerald F.

2002-01-01

Variants of the hc ligase ribozyme, which catalyzes ligation of the 3' end of an RNA substrate to the 5' end of the ribozyme, were utilized to evolve a ribozyme that catalyzes ligation reactions on an external RNA template. The evolved ribozyme catalyzes the joining of an oligonucleotide 3'-hydroxyl to the 5'-triphosphate of an RNA hairpin molecule. The ribozyme can also utilize various substrate sequences, demonstrating a largely sequence-independent mechanism for substrate recognition. The ribozyme also carries out the ligation of two oligonucleotides that are bound at adjacent positions on a complementary template. Finally, it catalyzes addition of mononucleoside '5-triphosphates onto the '3 end of an oligonucleotide primer in a template-dependent manner. The development of ribozymes that catalyze polymerase-type reactions contributes to the notion that an RNA world could have existed during the early history of life on Earth.

Two step esterification-transesterification process of wet greasy sewage sludge for biodiesel production.

PubMed

Urrutia, C; Sangaletti-Gerhard, N; Cea, M; Suazo, A; Aliberti, A; Navia, R

2016-01-01

Sewage sludge generated in municipal wastewater treatment plants was used as a feedstock for biodiesel production via esterification/transesterification in a two-step process. In the first esterification step, greasy and secondary sludge were tested using acid and enzymatic catalysts. The results indicate that both catalysts performed the esterification of free fatty acids (FFA) simultaneously with the transesterification of triacylglycerols (TAG). Acid catalyst demonstrated better performance in FFA esterification compared to TAG transesterification, while enzymatic catalyst showed the ability to first hydrolyze TAG in FFA, which were esterified to methyl esters. In addition, FAME concentration using greasy sludge were higher (63.9% and 58.7%), compared with those of secondary sludge (11% and 16%), using acid and enzymatic catalysts, respectively. Therefore, only greasy sludge was used in the second step of alkaline transesterification. The alkaline transesterification of the previously esterified greasy sludge reached a maximum FAME concentration of 65.4% when using acid catalyst. Copyright © 2015 Elsevier Ltd. All rights reserved.

Transesterification of Waste Activated Sludge for Biosolids Reduction and Biodiesel Production.

PubMed

Maeng, Min Ho; Cha, Daniel K

2018-02-01

  Transesterification of waste activated sludge (WAS) was evaluated as a cost-effective technique to reduce excess biosolids and recover biodiesel feedstock from activated sludge treatment processes. A laboratory-scale sequencing batch reactor (SBR) was operated with recycling transesterification-treated WAS back to the aeration basin. Seventy percent recycling of WAS resulted in a 48% reduction of excess biosolids in comparison with a conventional SBR, which was operated in parallel as the control SBR. Biodiesel recovery of 8.0% (dried weight basis) was achieved at an optimum transesterification condition using acidic methanol and xylene as cosolvent. Average effluent soluble chemical oxygen demand (COD) and total suspended solids (TSS) concentrations from the test SBR and control SBR were comparable, indicating that the recycling of transesterification-treated WAS did not have detrimental effect on the effluent quality. This study demonstrated that transesterification and recycling of WAS may be a feasible technique for reducing excess biosolids, while producing valuable biodiesel feedstock from the activated sludge process.

Development of a Lewis Base Catalyzed Selenocyclization Reaction

ERIC Educational Resources Information Center

Collins, William

2009-01-01

The concept of Lewis base activation of selenium Lewis acids has been effectively reduced to practice in the Lewis base catalyzed selenofunctionalization of unactivated olefins. In this reaction, the weakly acidic species, "N"-phenylselenyl succinimide, is cooperatively activated by the addition of a "soft" Lewis base donor (phosphine sulfides,…

Pd-Catalyzed Cross-Coupling Reactions of Amides and Aryl Mesylates

PubMed Central

Dooleweerdt, Karin; Fors, Brett P.; Buchwald, Stephen L.

2010-01-01

A catalyst, based on a biarylphosphine ligand, for the Pd-catalyzed cross-coupling reactions of amides and aryl mesylates is described. This system allows an array of aryl and heteroaryl mesylates to be transformed into the corresponding N-arylamides in moderate to excellent yields. PMID:20420379

Enzyme Catalysis and the Gibbs Energy

ERIC Educational Resources Information Center

Ault, Addison

2009-01-01

Gibbs-energy profiles are often introduced during the first semester of organic chemistry, but are less often presented in connection with enzyme-catalyzed reactions. In this article I show how the Gibbs-energy profile corresponds to the characteristic kinetics of a simple enzyme-catalyzed reaction. (Contains 1 figure and 1 note.)

LEWIS ACID-CATALYZED REACTIONS IN PROTIC MEDIA - LANTHANIDE-CATALYZED REACTIONS OF INDOLES WITH ALDEHYDES OR KETONES. (R826123)

EPA Science Inventory

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

Egg shell waste as heterogeneous nanocatalyst for biodiesel production: Optimized by response surface methodology.

PubMed

Pandit, Priti R; Fulekar, M H

2017-08-01

Worldwide consumption of hen eggs results in availability of large amount of discarded egg waste particularly egg shells. In the present study, the waste shells were utilized for the synthesis of highly active heterogeneous calcium oxide (CaO) nanocatalyst to transesterify dry biomass into methyl esters (biodiesel). The CaO nanocatalyst was synthesied by calcination-hydration-dehydration technique and fully characterized by infrared spectroscopy, X-ray powder diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), brunauer-emmett-teller (BET) elemental and thermogravimetric analysis. TEM image showed that the nano catalyst had spherical shape with average particle size of 75 nm. BET analysis indicated that the catalyst specific surface area was 16.4 m 2  g -1 with average pore diameter of 5.07 nm. The effect of nano CaO catalyst was investigated by direct transesterification of dry biomass into biodiesel along with other reaction parameters such as catalyst ratio, reaction time and stirring rate. The impact of the transesterification reaction parameters and microalgal biodiesel yield were analyzed by response surface methodology based on a full factorial, central composite design. The significance of the predicted mode was verified and 86.41% microalgal biodiesel yield was reported at optimal parameter conditions 1.7% (w/w), catalyst ratio, 3.6 h reaction time and stirring rate of 140.6 rpm. The biodiesel conversion was determined by 1 H nuclear magnetic resonance spectroscopy (NMR). The fuel properties of prepared biodiesel were found to be highly comply with the biodiesel standard ASTMD6751 and EN14214. Copyright © 2017 Elsevier Ltd. All rights reserved.

Two Palladium-Catalyzed Domino Reactions from One Set of Substrates/Reagents: Efficient Synthesis of Substituted Indenes and cis-Stilbenoid Hydrocarbons from the Same Internal Alkynes and Hindered Grignard Reagents

PubMed Central

Dong, Cheng-Guo; Yeung, Pik; Hu, Qiao-Sheng

2008-01-01

Two types of domino reactions from the same internal alkynes and hindered Grignard reagents based on carbopalladation, Pd-catalyzed cross-coupling reaction and C-H activation strategy are described. The realization of these domino reactions relied on the control of the use of the ligand and the reaction temperature. Our study provides an efficient access to useful polysubstituted indenes and cis-substituted stilbenes, and may offer new means to the development of tandem/domino reactions in a more efficient way. PMID:17217305

Kinetics of non-catalyzed hydrolysis of tannin in high temperature liquid water*

PubMed Central

Lu, Li-li; Lu, Xiu-yang; Ma, Nan

2008-01-01

High temperature liquid water (HTLW) has drawn increasing attention as an environmentally benign medium for organic chemical reactions, especially acid-/base-catalyzed reactions. Non-catalyzed hydrolyses of gallotannin and tara tannin in HTLW for the simultaneous preparation of gallic acid (GA) and pyrogallol (PY) are under investigation in our laboratory. In this study, the hydrolysis kinetics of gallotannin and tara tannin were determined. The reaction is indicated to be a typical consecutive first-order one in which GA has formed as a main intermediate and PY as the final product. Selective decomposition of tannin in HTLW was proved to be possible by adjusting reaction temperature and time. The present results provide an important basic data and reference for the green preparation of GA and PY. PMID:18500780

Co2(CO)8-catalyzed intramolecular hetero-Pauson-Khand reaction of alkynecarbodiimide: synthesis of (+/-)-physostigmine.

PubMed

Mukai, Chisato; Yoshida, Tatsunori; Sorimachi, Mao; Odani, Akira

2006-01-05

[reaction: see text] Herein we describe a novel Co(2)(CO)(8)-catalyzed intramolecular aza-Pauson-Khand-type reaction of alkynecarbodiimide derivatives affords pyrrolo[2,3-b]indol-2-one ring systems in reasonable yields. This is the first reported Co(2)(CO)(8) successfully applied in the hetero-Pauson-Khand reaction. Significantly, the transformation of one of our pyrrolo[2,3-b]indol-2-one derivatives into the indole alkaloid, (+/-)-physostigmine, was completed in a highly stereoselective manner.

A simple, multidimensional approach to high-throughput discovery of catalytic reactions.

PubMed

Robbins, Daniel W; Hartwig, John F

2011-09-09

Transition metal complexes catalyze many important reactions that are employed in medicine, materials science, and energy production. Although high-throughput methods for the discovery of catalysts that would mirror related approaches for the discovery of medicinally active compounds have been the focus of much attention, these methods have not been sufficiently general or accessible to typical synthetic laboratories to be adopted widely. We report a method to evaluate a broad range of catalysts for potential coupling reactions with the use of simple laboratory equipment. Specifically, we screen an array of catalysts and ligands with a diverse mixture of substrates and then use mass spectrometry to identify reaction products that, by design, exceed the mass of any single substrate. With this method, we discovered a copper-catalyzed alkyne hydroamination and two nickel-catalyzed hydroarylation reactions, each of which displays excellent functional-group tolerance.

Influence of hydroxylamine conformation on stereocontrol in Pd-catalyzed isoxazolidine-forming reactions.

PubMed

Lemen, Georgia S; Giampietro, Natalie C; Hay, Michael B; Wolfe, John P

2009-03-20

Palladium-catalyzed carboamination reactions between N-Boc-O-(but-3-enyl)hydroxylamine derivatives and aryl or alkenyl bromides afford cis-3,5- and trans-4,5-disubstituted isoxazolidines in good yield with up to >20:1 dr. The diastereoselectivity observed in the formation of cis-3,5-disubstituted isoxazolidines is superior to selectivities typically obtained in other transformations, such as 1,3-dipolar cycloaddition reactions, that provide these products. In addition, the stereocontrol in the C-N bond-forming Pd-catalyzed carboamination reactions of N-Boc-O-(but-3-enyl)hydroxylamines is significantly higher than that of related C-O bond-forming carboetherification reactions of N-benzyl-N-(but-3-enyl)hydroxylamine derivatives. This is likely due to a stereoelectronic preference for cyclization via transition states in which the Boc group is placed in a perpendicular orientation relative to the plane of the developing ring, which derives from the conformational equilibria of substituted hydroxylamines.

Acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicyclo[2.2.1]hept-5-ene with alcohols.

PubMed

Tait, Katrina; Horvath, Alysia; Blanchard, Nicolas; Tam, William

2017-01-01

The acid-catalyzed ring-opening reactions of a cyclopropanated 3-aza-2-oxabicylic alkene using alcohol nucleophiles were investigated. Although this acid-catalyzed ring-opening reaction did not cleave the cyclopropane unit as planned, this represent the first examples of ring-openings of cyclopropanated 3-aza-2-oxabicyclo[2.2.1]alkenes that lead to the cleavage of the C-O bond instead of the N-O bond. Different acid catalysts were tested and it was found that pyridinium toluenesulfonate in methanol gave the best yields in the ring-opening reactions. The scope of the reaction was successfully expanded to include primary, secondary, and tertiary alcohol nucleophiles. Through X-ray crystallography, the stereochemistry of the product was determined which confirmed an S N 2-like mechanism to form the ring-opened product.

Biodiesel synthesis using chicken manure biochar and waste cooking oil.

PubMed

Jung, Jong-Min; Lee, Sang-Ryong; Lee, Jechan; Lee, Taewoo; Tsang, Daniel C W; Kwon, Eilhann E

2017-11-01

This study laid an emphasis on the possible employment of biochar generated from pyrolysis of chicken manure to establish a green platform for producing biodiesel. To this end, the pseudo-catalytic transesterification reaction using chicken manure biochar and waste cooking oil was investigated. Compared with a commercial porous material (SiO 2 ), chicken manure biochar generated from 350°C showed better performance, resulting in 95.6% of the FAME yield at 350°C. The Ca species in chicken manure biochar imparted strong catalytic capability by providing the basicity for transesterification. The identified catalytic effect also led to the thermal cracking of unsaturated FAMEs, which decreased the overall FAME yield. For example, 40-60% of converted FAMEs were thermally degraded. To avoid undesirable thermal cracking arising from the high content of the Ca species in chicken manure biochar, the fabrication of chicken manure biochar at temperatures ≥350°C was highly recommended. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hyperbaric hyperoxia reversibly inhibits erythrocyte phospholipid fatty acid turnover

NASA Technical Reports Server (NTRS)

Dise, Craig A.; Clark, James M.; Lambersten, Christian J.; Goodman, David B. P.

1987-01-01

The effect of hyperbaric hyperoxia on the acylation of membrane phospholipid was studied by measuring the rates of activation of exogenous tritiated oleic acid to acyl thioester and of transesterification of the thioester into membrane phospholipids in intact human erythrocytes obtained 1 h after an exposure of the subjects to a hyperbaric oxygen atmosphere (3.5 h, 100 pct O2, 3 ATA). Exposure to pure oxygen was found to inhibit both the acylation and transesterification reactions by more than 30 percent, with partial recovery detected 24 h later. On the other hand, no rate changes were observed when isolated membranes from the same batches of cells were used in similar experiments. It is suggested that the decrease in the incorporation of tritiated oleic acid after hyperbaric hyperoxia may reflect an early event in the pathogenesis of oxygen-induced cellular injury and that it may be a useful index for the assessment of the tolerance of tissues to hyperoxia.

Concurrent production of biodiesel and chemicals through wet in situ transesterification of microalgae.

PubMed

Im, Hanjin; Kim, Bora; Lee, Jae W

2015-10-01

This work addresses an unprecedented way of co-producing biodiesel (FAEE) and valuable chemicals of ethyl levulinate (EL), ethyl formate (EF) and diethyl ether (DEE) from wet in situ transesterification of microalgae. EL, EF, and DEE were significantly produced up to 23.1%, 10.3%, and 52.1% of the maximum FAEE mass with the FAEE yield higher than 90% at 125 °C. Experiments to elucidate a detailed route of EL and EF synthesis were fulfilled and it was found that its main route to the production of EL and EF was the acid hydrolysis of algal cells and esterification with ethanol. To investigate the effect of reaction variables on the products yields, comprehensive experiments were carried out with varying temperatures, solvent and alcohol volumes, moisture contents and catalyst amounts. Coproduction of DEE, EL, EF and FAEE can contribute to elevating the economic feasibility of microalgae-based biodiesel supply chain. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Comparative assessment of Cladophora, Spirogyra and Oedogonium biomass for the production of fatty acid methyl esters].

PubMed

Haq, I; Muhammad, A; Hameed, U

2014-01-01

The use of alternative fuels for the mitigation of ecological impacts by use of diesel has been focus of intensive research. In the present work, algal oils extracted from cultivated biomass of Cladophora sp., Spirogyra sp. and Oedogonium sp. were evaluated for the lipase-mediated synthesis of fatty acid monoalkyl esters (FAME, biodiesel). To optimize the transesterification of these oils, different parameters such as the alkyl group donor, reaction temperature, stirring time and oil to alcohol ratio were investigated. Four different alcohols i.e. methanol, ethanol, n-propanol and n-butanol were tested as alkyl group donor for the biosynthesis FAME and methanol was found to be the best. Similarly, temperature 50 C and stirring time of 6 h were optimized for the transesterification of oils with methanol. The maximum biodiesel conversions from Cladophora (75.0%), Spirogyra (87.5%) and Oedogonium (92.0%) were obtained when oil to alcohol ratio was 1 : 8.

Cu-catalyzed aerobic oxidative cyclizations of 3-N-hydroxyamino-1,2-propadienes with alcohols, thiols, and amines to form α-O-, S-, and N-substituted 4-methylquinoline derivatives.

PubMed

Sharma, Pankaj; Liu, Rai-Shung

2015-03-16

A one-pot, two-step synthesis of α-O-, S-, and N-substituted 4-methylquinoline derivatives through Cu-catalyzed aerobic oxidations of N-hydroxyaminoallenes with alcohols, thiols, and amines is described. This reaction sequence involves an initial oxidation of N-hydroxyaminoallenes with NuH (Nu = OH, OR, NHR, and SR) to form 3-substituted 2-en-1-ones, followed by Brønsted acid catalyzed intramolecular cyclizations of the resulting products. Our mechanistic analysis suggests that the reactions proceed through a radical-type mechanism rather than a typical nitrone-intermediate route. The utility of this new Cu-catalyzed reaction is shown by its applicability to the synthesis of several 2-amino-4-methylquinoline derivatives, which are known to be key precursors to several bioactive molecules. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A: The Progression of a Catalytic Immune Response. B: Molecular Recognition of Anions by Silica Bound Sapphyrin

DTIC Science & Technology

1994-08-01

Diels - Alder reactions (58-60), Claisen rearrangements (43-45), olefin isomerization (73), a O-elimination (74), an asymmetric ketone reduction (54...phosphorothioate hapten3 ........ 19 Figure 5. Carboxylic acid hydrolysis .................... 21 Figure 6. Reaction coordinates for antibody catalyzed ...and catalyze the reaction. Thus, it is important to design transition analogs that closely mimic the transition state in every possible chemical

Two palladium-catalyzed domino reactions from one set of substrates/reagents: efficient synthesis of substituted indenes and cis-stilbenoid hydrocarbons from the same internal alkynes and hindered Grignard reagents.

PubMed

Dong, Cheng-Guo; Yeung, Pik; Hu, Qiao-Sheng

2007-01-18

Two types of domino reactions from the same internal alkynes and hindered Grignard reagents based on carbopalladation, Pd-catalyzed cross-coupling reaction, and a C-H activation strategy are described. The realization of these domino reactions relied on the control of the use of the ligand and the reaction temperature. Our study provides efficient access to useful polysubstituted indenes and cis-substituted stilbenes and may offer a new means of development of tandem/domino reactions in a more efficient way. [reaction: see text].

OXALOACETATE DECARBOXYLATION AND OXALOACETATE-CARBON DIOXIDE EXCHANGE IN ACETOBACTER XYLINUM

PubMed Central

Benziman, Moshe; Heller, N.

1964-01-01

Benziman, Moshe (The Hebrew University of Jerusalem, Jerusalem, Israel), and N. Heller. Oxaloacetate decarboxylation and oxaloacetate-carbon dioxide exchange in Acetobacter xylinum. J. Bacteriol. 88:1678–1687. 1964.—Extracts of Acetobacter xylinum, prepared by sonic treatment, were shown to catalyze the decarboxylation of oxaloacetate (OAA) to pyruvate and CO2, and the exchange of C14-carbon dioxide into the β-carboxyl of OAA. Fractionation of the extracts with ammonium sulfate resulted in a 10-fold increase of the specific activity of the enzyme system catalyzing the CO2 exchange and OAA decarboxylation reactions. The purified preparation catalyzed the exchange of pyruvate-3-C14 into OAA. Similar pH curves with a pH optimum of 5.6 were obtained for the CO2 exchange and OAA decarboxylation reactions. Both reactions require the presence of Mn2+ or Mg2+ ions. OAA decarboxylation was more strongly inhibited than the exchange of CO2 by dialysis or metal-chelating agents. Avidin did not inhibit either reaction. Adenosine triphosphate (ATP), adenosine diphosphate (ADP), guanosine triphosphate (GTP), guanosine diphosphate (GDP), pyrophosphate, or inorganic phosphate did not promote OAA decarboxylation and the CO2-exchange reaction catalyzed by the purified preparation. The purified preparation failed to catalyze the carboxylation of phosphoenolpyruvate in the presence of GDP, ADP, or inorganic phosphate, and that of pyruvate in the presence of ATP or GTP, even when supplemented with an OAA-trapping system. A scheme for OAA decarboxylation which could account for the observed exchange reactions and for the failure to obtain net fixation of CO2 is proposed. The relation between the exchange reaction and the synthesis of cellulose from pyruvate by A. xylinum is discussed. PMID:14240957

Applicability of PM3 to transphosphorylation reaction path: Toward designing a minimal ribozyme

NASA Technical Reports Server (NTRS)

Manchester, John I.; Shibata, Masayuki; Setlik, Robert F.; Ornstein, Rick L.; Rein, Robert

1993-01-01

A growing body of evidence shows that RNA can catalyze many of the reactions necessary both for replication of genetic material and the possible transition into the modern protein-based world. However, contemporary ribozymes are too large to have self-assembled from a prebiotic oligonucleotide pool. Still, it is likely that the major features of the earliest ribozymes have been preserved as molecular fossils in the catalytic RNA of today. Therefore, the search for a minimal ribozyme has been aimed at finding the necessary structural features of a modern ribozyme (Beaudry and Joyce, 1990). Both a three-dimensional model and quantum chemical calculations are required to quantitatively determine the effects of structural features of the ribozyme on the reaction it catalyzes. Using this model, quantum chemical calculations must be performed to determine quantitatively the effects of structural features on catalysis. Previous studies of the reaction path have been conducted at the ab initio level, but these methods are limited to small models due to enormous computational requirements. Semiempirical methods have been applied to large systems in the past; however, the accuracy of these methods depends largely on a simple model of the ribozyme-catalyzed reaction, or hydrolysis of phosphoric acid. We find that the results are qualitatively similar to ab initio results using large basis sets. Therefore, PM3 is suitable for studying the reaction path of the ribozyme-catalyzed reaction.

Spatial and temporal control of microwave triggered chemiluminescence: a protein detection platform.

PubMed

Previte, Michael J R; Aslan, Kadir; Geddes, Chris D

2007-09-15

We have combined the principles of microwave circuitry and antenna design and our recent work in microwave-triggered metal-enhanced chemiluminescence to now "trigger" chemically and enzyme-catalyzed chemiluminescent reactions with spatial and temporal control. With this technology platform, we achieve spatial and temporal control of enzyme and chemically catalyzed chemiluminescence reactions to achieve more than 500-fold increases in "on-demand" photon flux from chemically catalyzed chemiluminescent reactions. We also report a 6-fold increase in photon flux from HRP-catalyzed assays on disposable coverslips functionalized with HRP and placed proximal to the substrates modified with thin-film aluminum triangle disjointed "bow-tie" structures. In addition, we demonstrate the applicability of this technology to develop multiplexed or high-throughput chemiluminescent assays. We also demonstrate the clinical and biological relevance of this technology platform by affixing aluminum structures in proximity to HRP protein immobilized on nitrocellulose to improve the sensitivity for this model Western blot scheme by 50-fold. We believe analytical applications that rely on enzyme-catalyzed chemiluminescence, such as immunoassays, may greatly benefit from this new platform technology.

A new family of nucleophiles for photoinduced, copper-catalyzed cross-couplings via single-electron transfer: reactions of thiols with aryl halides under mild conditions (O °C).

PubMed

Uyeda, Christopher; Tan, Yichen; Fu, Gregory C; Peters, Jonas C

2013-06-26

Building on the known photophysical properties of well-defined copper-carbazolide complexes, we have recently described photoinduced, copper-catalyzed N-arylations and N-alkylations of carbazoles. Until now, there have been no examples of the use of other families of heteroatom nucleophiles in such photoinduced processes. Herein, we report a versatile photoinduced, copper-catalyzed method for coupling aryl thiols with aryl halides, wherein a single set of reaction conditions, using inexpensive CuI as a precatalyst without the need for an added ligand, is effective for a wide range of coupling partners. As far as we are aware, copper-catalyzed C-S cross-couplings at 0 °C have not previously been achieved, which renders our observation of efficient reaction of an unactivated aryl iodide at -40 °C especially striking. Mechanistic investigations are consistent with these photoinduced C-S cross-couplings following a SET/radical pathway for C-X bond cleavage (via a Cu(I)-thiolate), which contrasts with nonphotoinduced, copper-catalyzed processes wherein a concerted mechanism is believed to occur.

First application of an efficient and versatile ligand for copper-catalyzed cross-coupling reactions of vinyl halides with N-heterocycles and phenols.

PubMed

Kabir, M Shahjahan; Lorenz, Michael; Namjoshi, Ojas A; Cook, James M

2010-02-05

2-Pyridin-2-yl-1H-benzoimidazole L3 is presented as a new, efficient, and versatile bidentate N-donor ligand suitable for the copper-catalyzed formation of vinyl C-N and C-O bonds. This inexpensive and easily prepared ligand facilitates copper-catalyzed cross-coupling reactions of alkenyl bromides and iodides with N-heterocycles and phenols to afford the desired cross-coupled products in good to excellent yields with full retention of stereochemistry. This method is particularly noteworthy given its efficiency, that is, mild reaction conditions, low catalyst loading, simplicity, versatility, and exceptional level of functional group tolerance.

First Application of An Efficient and Versatile Ligand for Copper-Catalyzed Cross-Coupling Reactions of Vinyl Halides with N-Heterocycles and Phenols

PubMed Central

Kabir, M. Shahjahan; Lorenz, Michael; Namjoshi, Ojas A.; Cook, James M.

2010-01-01

2-Pyridin-2-yl-1H-benzoimidazole L3 is presented as a new, efficient, and versatile bidentate N-donor ligand suitable for the copper-catalyzed formation of vinyl C-N and C-O bonds. This inexpensive and easily prepared ligand facilitates copper-catalyzed cross-coupling reactions of alkenyl bromides and iodides with N-heterocycles and phenols to afford the desired cross-coupled products in good to excellent yields with full retention of stereochemistry. This method is particularly noteworthy given its efficiency i.e., mild reaction conditions, low catalyst loading, simplicity, versatility, and exceptional level of functional group tolerance. PMID:20039699

Osmium (VI) complexes of the 3', 5'-dinucleoside monophosphates, ApU and UpA.

PubMed

Daniel, F B; Behrman, E J

1976-02-10

The dinucleoside monophosphates, ApU and UpA, react with potassium osmate (VI) and 2,2'-bipyridyl to form the corresponding oxo-osmium (VI) bipyridyl sugar ester in which the osmate group is bonded to the terminal 2',3'-glycol. Osmium (VIII) tetroxide and 2,2'-bipyridyl react with the dinucleosides to form the corresponding oxo-osmium (VI) bipyridyl heterocyclic esters which result from addition of the tetroxide to the 5,6-double bond of the uracil residue. Although capable of transesterification reactions, these heterocyclic esters are exceptionally stable toward exchange reactions in solution. No apparent exchange was observed after 1 month. This reaction thus seems promising for single-site osmium labeling in polynucleotides.

Pyrimidine Nucleosides with a Reactive (β-Chlorovinyl)sulfone or (β-Keto)sulfone Group at the C5 Position, Their Reactions with Nucleophiles and Electrophiles, and Their Polymerase-Catalyzed Incorporation into DNA

PubMed Central

2018-01-01

Transition-metal-catalyzed chlorosulfonylation of 5-ethynylpyrimidine nucleosides provided (E)-5-(β-chlorovinyl)sulfones A, which undergo nucleophilic substitution with amines or thiols affording B. The treatment of vinyl sulfones A with ammonia followed by acid-catalyzed hydrolysis of the intermediary β-sulfonylvinylamines gave 5-(β-keto)sulfones C. The latter reacts with electrophiles, yielding α-carbon-alkylated or -sulfanylated analogues D. The 5′-triphosphates of A and C were incorporated into double-stranded DNA, using open and one-nucleotide gap substrates, by human or Escherichia coli DNA-polymerase-catalyzed reactions. PMID:29732453

Statistical optimization and operational stability of Rhizomucor miehei lipase supported on magnetic chitosan/chitin nanoparticles for synthesis of pentyl valerate.

PubMed

Rahman, Ida Nurhazwani Abdul; Attan, Nursyafreena; Mahat, Naji Arafat; Jamalis, Joazaizulfazli; Abdul Keyon, Aemi S; Kurniawan, Cepi; Wahab, Roswanira Abdul

2018-04-24

The chemical-catalyzed transesterification process to produce biofuels i.e. pentyl valerate (PeVa) is environmentally unfriendly, energy-intensive with tedious downstream treatment. The present work reports the use of Rhizomucor miehei lipase (RML) crosslinked onto magnetic chitosan/chitin nanoparticles (RML-CS/CH/MNPs). The approach used to immobilize RML onto the CS/CH/MNPs yielded RML-CS/CH/MNPs with an immobilized protein loading and specific activity of 7.6 mg/g and 5.0 U·g -1 , respectively. This was confirmed by assessing data of field emission scanning electron microscopy, X-ray diffraction, thermal gravimetric analysis and Fourier transform infrared spectroscopy. A three-level-four-factor Box-Behnken design (incubation time, temperature, substrate molar ratio, and enzyme loading) was used to optimize the RML-CS/CH/MNP-catalyzed esterification synthesis of PeVa. Under optimum condition, the maximum yield of PeVa (97.8%) can be achieved in 5 h at 50 °C using molar ratio valeric acid:pentanol (1:2) and an enzyme load of 2 mg/mL. Consequently, operational stability experiments showed that the protocol adopted to prepare the CS/CH/MNP nanoparticles had increased the durability of RML. The RML-CS/CH/MNP could catalyze up to eight successive esterification cycles to produce PeVa. The study also demonstrated the functionality of CS/CH/MNP nanoparticles as an eco-friendly support matrix for improving enzymatic activity and operational stability of RML to produce PeVa. Copyright © 2018. Published by Elsevier B.V.

Enzymatic synthesis of chiral amino‐alcohols by coupling transketolase and transaminase‐catalyzed reactions in a cascading continuous‐flow microreactor system

PubMed Central

Gruber, Pia; Carvalho, Filipe; Marques, Marco P. C.; O'Sullivan, Brian; Subrizi, Fabiana; Dobrijevic, Dragana; Ward, John; Hailes, Helen C.; Fernandes, Pedro; Wohlgemuth, Roland; Baganz, Frank

2017-01-01

Abstract Rapid biocatalytic process development and intensification continues to be challenging with currently available methods. Chiral amino‐alcohols are of particular interest as they represent key industrial synthons for the production of complex molecules and optically pure pharmaceuticals. (2S,3R)‐2‐amino‐1,3,4‐butanetriol (ABT), a building block for the synthesis of protease inhibitors and detoxifying agents, can be synthesized from simple, non‐chiral starting materials, by coupling a transketolase‐ and a transaminase‐catalyzed reaction. However, until today, full conversion has not been shown and, typically, long reaction times are reported, making process modifications and improvement challenging. In this contribution, we present a novel microreactor‐based approach based on free enzymes, and we report for the first time full conversion of ABT in a coupled enzyme cascade for both batch and continuous‐flow systems. Using the compartmentalization of the reactions afforded by the microreactor cascade, we overcame inhibitory effects, increased the activity per unit volume, and optimized individual reaction conditions. The transketolase‐catalyzed reaction was completed in under 10 min with a volumetric activity of 3.25 U ml−1. Following optimization of the transaminase‐catalyzed reaction, a volumetric activity of 10.8 U ml−1 was attained which led to full conversion of the coupled reaction in 2 hr. The presented approach illustrates how continuous‐flow microreactors can be applied for the design and optimization of biocatalytic processes. PMID:28986983

Cu-catalyzed C(sp³)-H bond activation reaction for direct preparation of cycloallyl esters from cycloalkanes and aromatic aldehydes.

PubMed

Zhao, Jincan; Fang, Hong; Han, Jianlin; Pan, Yi

2014-05-02

Cu-catalyzed dehydrogenation-olefination and esterification of C(sp(3))-H bonds of cycloalkanes with TBHP as an oxidant has been developed. The reaction involves four C-H bond activations and gives cycloallyl ester products directly from cycloalkanes and aromatic aldehydes.

Rhodium-catalyzed kinetic resolution of tertiary homoallyl alcohols via stereoselective carbon-carbon bond cleavage.

PubMed

Shintani, Ryo; Takatsu, Keishi; Hayashi, Tamio

2008-03-20

A nonenzymatic kinetic resolution of tertiary homoallyl alcohols has been developed through a rhodium-catalyzed retro-allylation reaction under simple conditions. Selectivity factors of up to 12 have been achieved by employing (R)-H8-binap as the ligand, and the reaction can be conducted on a preparative scale.

The effect of Mg/2+/ and Ca/2+/ on urea-catalyzed phosphorylation reactions

NASA Technical Reports Server (NTRS)

Handschuk, G. J.; Lohrmann, R.; Orgel, L. E.

1973-01-01

The effect of Mg(2+) and Ca(2+) on phosphorylation reactions catalyzed by urea is investigated, showing that Mg(2+) improves markedly the yield of products containing pyrophosphate bonds. Yields of up to 25% of uridine diphosphate can be obtained with struvite at temperatures as low as 65 C.

Pd-catalyzed one-pot synthesis of polysubstituted acrylamidines from isocyanides, diazo compounds, and imines.

PubMed

Yan, Xu; Liao, Jinxi; Lu, Yongzhi; Liu, Jinsong; Zeng, Youlin; Cai, Qian

2013-05-17

A novel and efficient Pd-catalyzed one-pot reaction of ethyl diazoacetate, isocyanides, and imines for the synthesis of acrylamidines was developed. The multicomponent reaction may have occurred through an unpredicted ring-opening process of the ketenimine-imine [2 + 2] intermediate to form the acrylamidine products.

A facile synthesis of pyrrolo[2,3-b]quinolines via a Rh(I)-catalyzed carbodiimide-Pauson-Khand-type reaction.

PubMed

Saito, Takao; Furukawa, Naoki; Otani, Takashi

2010-03-07

A new straightforward synthetic method for 2,3-dihydro-1H-pyrrolo[2,3-b]quinolin-2-ones via a [RhCl(CO)(2)](2)-dppp catalyzed Pauson-Khand-type reaction of N-[2-(2-alkyn-1-yl)phenyl]carbodiimides is reported.

Cu-catalyzed formal methylative and hydrogenative carboxylation of alkynes with carbon dioxide: efficient synthesis of α,β-unsaturated carboxylic acids.

PubMed

Takimoto, Masanori; Hou, Zhaomin

2013-08-19

The sequential hydroalumination or methylalumination of various alkynes catalyzed by different catalyst systems, such those based on Sc, Zr, and Ni complexes, and the subsequent carboxylation of the resulting alkenylaluminum species with CO2 catalyzed by an N-heterocyclic carbene (NHC)-copper catalyst have been examined in detail. The regio- and stereoselectivity of the overall reaction relied largely on the hydroalumination or methylalumination reactions, which significantly depended on the catalyst and alkyne substrates. The subsequent Cu-catalyzed carboxylation proceeded with retention of the stereoconfiguration of the alkenylaluminum species. All the reactions could be carried out in one-pot to afford efficiently a variety of α,β-unsaturated carboxylic acids with well-controlled configurations, which are difficult to construct by previously reported methods. This protocol could be practically useful and attractive because of its high regio- and stereoselectivity, simple one-pot reaction operation, and the use of CO2 as a starting material. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Reactivity of a Carbon-Supported Single-Site Molybdenum Dioxo Catalyst for Biodiesel Synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mouat, Aidan R.; Lohr, Tracy L.; Wegener, Evan C.

2016-08-23

A single-site molybdenum dioxo catalyst, (O c) 2Mo(=O) 2@C, was prepared via direct grafting of MoO 2Cl 2(dme) (dme = 1,2-dimethoxyethane) on high-surface- area activated carbon. The physicochemical and chemical properties of this catalyst were fully characterized by N 2 physisorption, ICP-AES/OES, PXRD, STEM, XPS, XAS, temperature-programmed reduction with H 2 (TPR-H 2), and temperature-programmed NH 3 desorption (TPD-NH 3). The single-site nature of the Mo species is corroborated by XPS and TPR-H 2 data, and it exhibits the lowest reported MoO x Tmax of reduction reported to date, suggesting a highly reactive MoVI center. (O c) 2Mo(=O) 2@C catalyzesmore » the transesterification of a variety of esters and triglycerides with ethanol, exhibiting high activity at moderate temperatures (60-90 °C) and with negligible deactivation. (O c) 2Mo(=O) 2@C is resistant to water and can be recycled at least three times with no loss of activity. The transesterification reaction is determined experimentally to be first order in [ethanol] and first order in [Mo] with ΔH = 10.5(8) kcal mol -1 and ΔS = -32(2) eu. The low energy of activation is consistent with the moderate conditions needed to achieve rapid turnover. This highly active carbon-supported single-site molybdenum dioxo species is thus an efficient, robust, and lowcost catalyst with significant potential for transesterification processes.« less

Elucidation of the Pathway to Astaxanthin in the Flowers of Adonis aestivalis[C][W

PubMed Central

Cunningham, Francis X.; Gantt, Elisabeth

2011-01-01

A few species in the genus Adonis are the only land plants known to produce the valuable red ketocarotenoid astaxanthin in abundance. Here, we ascertain the pathway that leads from the β-rings of β-carotene, a carotenoid ubiquitous in plants, to the 3-hydroxy-4-keto-β-rings of astaxanthin (3,3′-dihydroxy-β,β-carotene-4,4’-dione) in the blood-red flowers of Adonis aestivalis, an ornamental and medicinal plant commonly known as summer pheasant’s eye. Two gene products were found to catalyze three distinct reactions, with the first and third reactions of the pathway catalyzed by the same enzyme. The pathway commences with the activation of the number 4 carbon of a β-ring in a reaction catalyzed by a carotenoid β-ring 4-dehydrogenase (CBFD), continues with the further dehydrogenation of this carbon to yield a carbonyl in a reaction catalyzed by a carotenoid 4-hydroxy-β-ring 4-dehydrogenase, and concludes with the addition of an hydroxyl group at the number 3 carbon in a reaction catalyzed by the erstwhile CBFD enzyme. The A. aestivalis pathway is both portable and robust, functioning efficiently in a simple bacterial host. Our elucidation of the pathway to astaxanthin in A. aestivalis provides enabling technology for development of a biological production process and reveals the evolutionary origin of this unusual plant pathway, one unrelated to and distinctly different from those used by bacteria, green algae, and fungi to synthesize astaxanthin. PMID:21862704

Carbon Isotope Measurements of Experimentally-Derived Hydrothermal Mineral-Catalyzed Organic Products by Pyrolysis-Isotope Ratio Mass Spectrometry

NASA Technical Reports Server (NTRS)

Socki, Richard A.; Fu, Qi; Niles, Paul B.

2011-01-01

We report results of experiments to measure the C isotope composition of mineral catalyzed organic compounds derived from high temperature and high pressure synthesis. These experiments make use of an innovative pyrolysis technique designed to extract and measure C isotopes. To date, our experiments have focused on the pyrolysis and C isotope ratio measurements of low-molecular weight intermediary hydrocarbons (organic acids and alcohols) and serve as a proof of concept for making C and H isotope measurements on more complicated mixtures of solid-phase hydrocarbons and intermediary products produced during high temperature and high pressure synthesis on mineral-catalyzed surfaces. The impetus for this work stems from recently reported observations of methane detected within the Martian atmosphere [1-4], coupled with evidence showing extensive water-rock interaction during Martian history [5-7]. Methane production on Mars could be the result of synthesis by mineral surface-catalyzed reduction of CO2 and/or CO by Fischer-Tropsch Type (FTT) reactions during serpentization reactions [8,9]. Others have conducted experimental studies to show that FTT reactions are plausible mechanisms for low-molecular weight hydrocarbon formation in hydrothermal systems at mid-ocean ridges [10-12]. Further, recent experiments by Fu et al. [13] focus on examining detailed C isotope measurements of hydrocarbons produced by surface-catalyzed mineral reactions. Work described in this paper details the experimental techniques used to measure intermediary organic reaction products (alcohols and organic acids).

Wash Bottle Laboratory Exercises: Iodide-Catalyzed H[subscript 2]O[subscript 2] Decomposition Reaction Kinetics Using the Initial Rate Approach

ERIC Educational Resources Information Center

Barlag, Rebecca; Nyasulu, Frazier

2010-01-01

A wash bottle water displacement scheme is used to determine the kinetics of the iodide-catalyzed H[subscript 2]O[subscript 2] decomposition reaction. The reagents (total volume 5.00 mL) are added to a test tube that is placed in a wash bottle containing water. The mass of the water displaced in [approximately]60 s is measured. The reaction is…

Copper-Catalyzed γ-Selective and Stereospecific Allylic Cross-Coupling with Secondary Alkylboranes.

PubMed

Yasuda, Yuto; Nagao, Kazunori; Shido, Yoshinori; Mori, Seiji; Ohmiya, Hirohisa; Sawamura, Masaya

2015-06-26

The scope of the copper-catalyzed coupling reactions between organoboron compounds and allylic phosphates is expanded significantly by employing triphenylphosphine as a ligand for copper, allowing the use of secondary alkylboron compounds. The reaction proceeds with complete γ-E-selectivity and preferential 1,3-syn stereoselectivity. The reaction of γ-silicon-substituted allylic phosphates affords enantioenriched α-stereogenic allylsilanes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Copper(I)-Catalyzed Chemoselective Coupling of Cyclopropanols with Diazoesters: Ring-Opening C-C Bond Formations.

PubMed

Zhang, Hang; Wu, Guojiao; Yi, Heng; Sun, Tong; Wang, Bo; Zhang, Yan; Dong, Guangbin; Wang, Jianbo

2017-03-27

Reported herein is an exceptional chemoselective ring-opening/C(sp 3 )-C(sp 3 ) bond formation in the copper(I)-catalyzed reaction of cyclopropanols with diazo esters. The conventional O-H insertion product is essentially suppressed by judicious choice of reaction conditions. DFT calculations provide insights into the reaction mechanism and the rationale for this unusual chemoselectivity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Glycerol triacetate as solvent and acyl donor in the production of isoamyl acetate with Candida antarctica lipase B.

PubMed

Wolfson, Adi; Atyya, Aviad; Dlugy, Christina; Tavor, Dorith

2010-03-01

Glycerol triacetate was successfully used as a green solvent and as the acyl donor in the transesterification of isoamyl alcohol to produce isoamyl acetate using free and immobilized Candida antarctica lipase B. Immobilized lipase was more catalytically active than free lipase and could be easily separated from the reaction mixture by filtration. In addition, it was found that increasing either the reaction temperature or the enzyme to substrate ratio increased the conversion of isoamyl alcohol. Using triacetin as the solvent also enabled the separation of product by simple extraction with petroleum ether and catalyst recycling.

Rational approaches for engineering novel functionalities in carbon-carbon bond forming enzymes

PubMed Central

Baker, Perrin; Seah, Stephen Y. K.

2012-01-01

Enzymes that catalyze carbon-carbon bond formation can be exploited as biocatalyst for synthetic organic chemistry. However, natural enzymes frequently do not possess the required properties or specificities to catalyze industrially useful transformations. This mini-review describes recent work using knowledge-guided site-specific mutagenesis of key active site residues to alter substrate specificity, stereospecificity and reaction specificity of these enzymes. In addition, examples of de novo designed enzymes that catalyze C-C bond reactions not found in nature will be discussed. PMID:24688644

Chemoselective chromium(II)-catalyzed cross-coupling reactions of dichlorinated heteroaromatics with functionalized aryl grignard reagents.

PubMed

Steib, Andreas K; Kuzmina, Olesya M; Fernandez, Sarah; Malhotra, Sushant; Knochel, Paul

2015-01-26

Chromium(II) chloride catalyzes the chemoselective cross-coupling reaction of dichloropyridines with a range of functionalized (hetero)aromatic Grignard reagents at room temperature. Functional groups, such as esters and acetals, are well tolerated in this transformation. Previously challenging substrates, quinolines and isoquinolines, participate in the selective Cr-catalyzed cross-coupling in cyclopentyl methyl ether (CPME) as the solvent. The effective purging of Cr salts is demonstrated by using various solid supports. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Direct asymmetric aldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral BINOL-derived zincate catalyst.

PubMed

Li, Hong; Da, Chao-Shan; Xiao, Yu-Hua; Li, Xiao; Su, Ya-Ning

2008-09-19

Direct asymmetric aldol reaction of aryl ketones with aryl aldehydes catalyzed by chiral metal complex is reported for the first time herein. Two novel semicrown chiral ligands 1a and 1b were synthesized from (S)- and (R)-BINOL, respectively, and then employed to catalyze the direct asymmetric aldol addition of aryl ketones to aryl aldehydes. Introduced with 2.0 equiv of diethylzinc, 1b had higher enantioselectivity than 1a. Up to 97% yield and up to 80% enantioselectivity were achieved.

Effect of Reaction Temperature on Biodiesel Production from Chlorella vulgaris using CuO/Zeolite as Heterogeneous Catalyst

NASA Astrophysics Data System (ADS)

Dianursanti; Delaamira, M.; Bismo, S.; Muharam, Y.

2017-02-01

Human needs for fossil energy increase every year. Biodiesel is the main way to resolve this world problem. Biodiesel produces from vegetable oil. But then, the alternative way came from the uses of microalgae in Chlorella vulgaris type causes by its simplicity of growing. In the other hand, this microalgae known for its high lipid content by considering several parameter such as light intensity, medium nutrition, pH and also salinity. Lipid content will be extracted by using Bligh-Dryer method which will be reacted with methanol along transesterification. Beside, there come another matter which is the utilization of homogeny catalyst. The difficulty of separation is the main matter so then biodiesel need to be washed in case normalizing the pH and this process will decrease the quality of biodiesel. To resolve this problem, we’ll be using a heterogeneous catalyst, zeolite, with ability to catalyst the process. Zeolite is easier to separate from the biodiesel so there will not be needed washing process. Heterogeneous catalyst work as well as homogeneous. Variation implemented on transesterification included reaction temperature of 40°C, 60°C, and 80°C. Reaction time, catalyst percentage and the solvent amount remain steady on 4 hours, 3% and 1:400. Complete best result obtained at 60°C with the yield of 36,78%. Through this, heterogeneous catalyst CuO/Zeolite proved to have a capability for replacing homogeneous catalyst and simplify the production of biodiesel particularly in separation step.

KF-loaded mesoporous Mg-Fe bi-metal oxides: high performance transesterification catalysts for biodiesel production.

PubMed

Tao, Guiju; Hua, Zile; Gao, Zhe; Zhu, Yan; Zhu, Yan; Chen, Yu; Shu, Zhu; Zhang, Lingxia; Shi, Jianlin

2013-09-21

Using newly developed mesoporous Mg-Fe bi-metal oxides as supports, a novel kind of high performance transesterification catalysts for biodiesel production has been synthesized. More importantly, the impregnation solvent was for the first time found to substantially affect the structures and catalytic performances of the resultant transesterification catalysts.

Insights into the Competing Mechanisms and Origin of Enantioselectivity for N-Heterocyclic Carbene-Catalyzed Reaction of Aldehyde with Enamide

NASA Astrophysics Data System (ADS)

Qiao, Yan; Chen, Xinhuan; Wei, Donghui; Chang, Junbiao

2016-12-01

Hydroacylation reactions and aza-benzoin reactions have attracted considerable attention from experimental chemists. Recently, Wang et al. reported an interesting reaction of N-heterocyclic carbene (NHC)-catalyzed addition of aldehyde to enamide, in which both hydroacylation and aza-benzoin reactions may be involved. Thus, understanding the competing relationship between them is of great interest. Now, density functional theory (DFT) investigation was performed to elucidate this issue. Our results reveal that enamide can tautomerize to its imine isomer with the assistance of HCO3-. The addition of NHC to aldehydes formed Breslow intermediate, which can go through cross-coupling with enamide via hydroacylation reaction or its imine isomer via aza-benzoin reaction. The aza-benzoin reaction requires relatively lower free energy barrier than the hydroacylation reaction. The more polar characteristic of C=N group in the imine isomers, and the more advantageous stereoelectronic effect in the carbon-carbon bond forming transition states in aza-benzoin pathway were identified to determine that the imine isomer can react with the Breslow intermediate more easily. Furthermore, the origin of enantioselectivities for the reaction was explored and reasonably explained by structural analyses on key transition states. The work should provide valuable insights for rational design of switchable NHC-catalyzed hydroacylation and aza-benzoin reactions with high stereoselectivity.

Nature's Strategy for Catalyzing Diels-Alder Reaction.

PubMed

Oikawa, Hideaki

2016-04-21

The enzymes catalyzing a Diels-Alder-type reaction have been attractive targets for organic chemists for years. Recently, Zheng et al. (2016) reported the structure of a formal monofunctional Diels-Alderase PyrI4 complexed with the product and unveiled a detailed catalytic mechanism of a highly important enzyme. Copyright © 2016 Elsevier Ltd. All rights reserved.

Method for facilitating catalyzed oxidation reactions, device for facilitating catalyzed oxidation reactions

DOEpatents

Beuhler, Robert J [East Moriches, NY; White, Michael G [Blue Point, NY; Hrbek, Jan [Rocky Point, NY

2006-08-15

A catalytic process for the oxidation of organic. Oxygen is loaded into a metal foil by heating the foil while in contact with an oxygen-containing fluid. After cooling the oxygen-activated foil to room temperature, oxygen diffuses through the foil and oxidizes reactants exposed to the other side of the foil.

Palladium-catalyzed three-component reaction of N-tosyl hydrazones, isonitriles and amines leading to amidines.

PubMed

Dai, Qiang; Jiang, Yan; Yu, Jin-Tao; Cheng, Jiang

2015-12-04

A palladium-catalyzed three-component reaction between N-tosyl hydrazones, aryl isonitriles and amines was developed, leading to amidines in moderate to good yields. This procedure features the rapid construction of amidine frameworks with high diversity and complexity. Ketenimines serve as intermediates, which encounter nucleophilic attack by amines to produce amidines.

Copper-Catalyzed C(sp2)-S Coupling Reactions for the Synthesis of Aryl Dithiocarbamates with Thiuram Disulfide Reagents.

PubMed

Dong, Zhi-Bing; Liu, Xing; Bolm, Carsten

2017-11-03

An efficient protocol for the copper-catalyzed preparation of aryl dithiocarbamates from aryl iodides and inexpensive, environmentally benign tetraalkylthiuram disulfides was developed. The features of mild reaction conditions, high yields, and broad substrate scope render this new approach synthetically attractive for the preparation of potentially biologically active compounds.

Efficient Method for the Determination of the Activation Energy of the Iodide-Catalyzed Decomposition of Hydrogen Peroxide

ERIC Educational Resources Information Center

Sweeney, William; Lee, James; Abid, Nauman; DeMeo, Stephen

2014-01-01

An experiment is described that determines the activation energy (E[subscript a]) of the iodide-catalyzed decomposition reaction of hydrogen peroxide in a much more efficient manner than previously reported in the literature. Hydrogen peroxide, spontaneously or with a catalyst, decomposes to oxygen and water. Because the decomposition reaction is…

Vanadium-Catalyzed C(sp3)–H Fluorination Reactions†

PubMed Central

Xia, Ji-Bao; Ma, Yuyong; Chen, Chuo

2014-01-01

Vanadium(III) oxide catalyzes the direct fluorination of C(sp3)–H groups with Selectfluor. This reaction is operationally simple. The catalyst and the reaction byproduct can be removed easily by filtration. Using this method, a fluorine atom can be introduced to the tertiary position of 1,4-cineole and L-menthone selectively. PMID:24976971

Gold-catalyzed synthesis of benzil derivatives and α-keto imides via oxidation of alkynes.

PubMed

Xu, Cheng-Fu; Xu, Mei; Jia, Yi-Xia; Li, Chuan-Ying

2011-03-18

An efficient process based on the gold-catalyzed redox reaction has been developed to oxidize 1,2-diarylacetylene or ynamide to 1,2-diaryldiketone or α-keto imide respectively. This process can tolerate a variety of functional groups and affords 1,2-dicarbonyl compounds in excellent yields under mild reaction conditions.