Effect of solvents and oil content on direct transesterification of wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized lipase as the biocatalyst.

PubMed

Tran, Dang-Thuan; Chen, Ching-Lung; Chang, Jo-Shu

2013-05-01

In this work, a one-step extraction/transesterification process was developed to directly convert wet oil-bearing microalgal biomass of Chlorella vulgaris ESP-31 into biodiesel using immobilized Burkholderia lipase as the catalyst. The microalgal biomass (water content of 86-91%; oil content 14-63%) was pre-treated by sonication to disrupt the cell walls and then directly mixed with methanol and solvent to carry out the enzymatic transesterification. Addition of a sufficient amount of solvent (hexane is most preferable) is required for the direct transesterification of wet microalgal biomass, as a hexane-to-methanol mass ratio of 1.65 was found optimal for the biodiesel conversion. The amount of methanol and hexane required for the direct transesterification process was also found to correlate with the lipid content of the microalga. The biodiesel synthesis process was more efficient and economic when the lipid content of the microalgal biomass was higher. Therefore, using high-lipid-content microalgae as feedstock appears to be desirable. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

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.

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.

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.

Lipid extraction methods from microalgal biomass harvested by two different paths: screening studies toward biodiesel production.

PubMed

Ríos, Sergio D; Castañeda, Joandiet; Torras, Carles; Farriol, Xavier; Salvadó, Joan

2013-04-01

Microalgae can grow rapidly and capture CO2 from the atmosphere to convert it into complex organic molecules such as lipids (biodiesel feedstock). High scale economically feasible microalgae based oil depends on optimizing the entire process production. This process can be divided in three very different but directly related steps (production, concentration, lipid extraction and transesterification). The aim of this study is to identify the best method of lipid extraction to undergo the potentiality of some microalgal biomass obtained from two different harvesting paths. The first path used all physicals concentration steps, and the second path was a combination of chemical and physical concentration steps. Three microalgae species were tested: Phaeodactylum tricornutum, Nannochloropsis gaditana, and Chaetoceros calcitrans One step lipid extraction-transesterification reached the same fatty acid methyl ester yield as the Bligh and Dyer and soxhlet extraction with n-hexane methods with the corresponding time, cost and solvent saving. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enzymatic enrichment of egg-yolk phosphatidylcholine with alpha-linolenic acid.

PubMed

Chojnacka, A; Gładkowski, W; Kiełbowicz, G; Wawrzeńczyk, C

2009-05-01

alpha-Linolenic acid (ALA) was incorporated at 28% into the sn-1 position of egg-yolk phospatidylcholine using Novozyme 435 in one-step transesterification process. Using phospholipase A(2) in a two-step process gave 25% incorporation of ALA into the sn-2 position.

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.

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.

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.

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.

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.

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.

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.

A whole biodiesel conversion process combining isolation, cultivation and in situ supercritical methanol transesterification of native microalgae.

PubMed

Jazzar, Souhir; Quesada-Medina, Joaquín; Olivares-Carrillo, Pilar; Marzouki, Mohamed Néjib; Acién-Fernández, Francisco Gabriel; Fernández-Sevilla, José María; Molina-Grima, Emilio; Smaali, Issam

2015-08-01

A coupled process combining microalgae production with direct supercritical biodiesel conversion using a reduced number of operating steps is proposed in this work. Two newly isolated native microalgae strains, identified as Chlorella sp. and Nannochloris sp., were cultivated in both batch and continuous modes. Maximum productivities were achieved during continuous cultures with 318mg/lday and 256mg/lday for Chlorella sp. and Nannochloris sp., respectively. Microalgae were further characterized by determining their photosynthetic performance and nutrient removal efficiency. Biodiesel was produced by catalyst-free in situ supercritical methanol transesterification of wet unwashed algal biomass (75wt.% of moisture). Maximum biodiesel yields of 45.62wt.% and 21.79wt.% were reached for Chlorella sp. and Nannochloris sp., respectively. The analysis of polyunsaturated fatty acids of Chlorella sp. showed a decrease in their proportion when comparing conventional and supercritical transesterification processes (from 37.4% to 13.9%, respectively), thus improving the quality of the biodiesel. Copyright © 2015 Elsevier Ltd. All rights reserved.

Industrial wastes as a promising renewable source for production of microbial lipid and direct transesterification of the lipid into biodiesel.

PubMed

Cheirsilp, Benjamas; Louhasakul, Yasmi

2013-08-01

Two strategies of converting industrial wastes to microbial lipid and direct transesterification of obtained lipid into biodiesel were attempted. Several oleaginous yeasts were cultivated on industrial wastes. The yeasts grew well on the wastes with low C/N ratio (i.e. serum latex) but accumulated high lipid content only when the wastes had a high C/N ratio (i.e. palm oil mill effluent and crude glycerol). The yeast lipids have similar fatty acid composition to that of plant oil indicating their potential use as biodiesel feedstocks. The combination of these wastes and two-phase cultivation for cell growth and lipid accumulation improved lipid productivity of the selected yeast. The direct transesterification process that eliminates cell drying and lipid extraction steps, gave comparable yield of biodiesel (fatty acid methyl ester >70% within 1h) to that of conventional method. These two successful strategies may contribute greatly to industrializing oil production from microbes and industrial wastes. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

In situ Transesterification of Microalgal Oil to Produce Algal Biodiesel

DOT National Transportation Integrated Search

2012-06-01

This research was to process whole microalgae cells for biodiesel production without first extracting lipids. The ultimate : goal is develop a novel process for algal biodiesel production directly from microalgae cells in a single step, i.e., in situ...

Effect of sludge features and extraction-esterification technology on the synthesis of biodiesel from secondary wastewater treatment sludges.

PubMed

Patiño, Yolanda; Mantecón, Laura G; Polo, Sara; Faba, Laura; Díaz, Eva; Ordóñez, Salvador

2018-01-01

Secondary sludge from municipal wastewater treatment plant is proposed as a promising alternative lipid feedstock for biodiesel production. A deep study combining different type of raw materials (sludge coming from the oxic, anoxic and anaerobic steps of the biological treatment) with different technologies (liquid-liquid and solid-liquid extractions followed by acid catalysed transesterification and in situ extraction-transesterification procedure) allows a complete comparison of available technologies. Different parameters - contact time, catalyst concentration, pretreatments - were considered, obtaining more than 17% FAMEs yield after 50min of sonication with the in situ procedure and 5% of H 2 SO 4 . This result corresponds to an increment of more than 65% respect to the best results reported at typical conditions. Experimental data were used to propose a mathematical model for this process, demonstrating that the mass transfer of lipids from the sludge to the liquid is the limiting step. Copyright © 2017 Elsevier Ltd. All rights reserved.

Optimization of one-step in situ transesterification method for accurate quantification of EPA in Nannochloropsis gaditana

DOE PAGES

Tang, Yuting; Zhang, Yue; Rosenberg, Julian N.; ...

2016-11-08

Microalgae are a valuable source of lipid feedstocks for biodiesel and valuable omega-3 fatty acids. Nannochloropsis gaditana has emerged as a promising producer of eicosapentaenoic acid (EPA) due to its fast growth rate and high EPA content. In the present study, the fatty acid profile of Nannochloropsis gaditana was found to be naturally high in EPA and devoid of docosahexaenoic acid (DHA), thereby providing an opportunity to maximize the efficacy of EPA production. Using an optimized one-step in situ transesterification method (methanol:biomass = 90 mL/g; HCl 5% by vol.; 70 °C; 1.5 h), the maximum fatty acid methyl ester (FAME)more » yield of Nannochloropsis gaditana cultivated under rich condition was quantified as 10.04% ± 0.08% by weight with EPA-yields as high as 4.02% ± 0.17% based on dry biomass. The total FAME and EPA yields were 1.58- and 1.23-fold higher separately than that obtained using conventional two-step method (solvent system: methanol and chloroform). Furthermore, this one-step in situ method provides a fast and simple method to measure fatty acid methyl ester (FAME) yields and could serve as a promising method to generate eicosapentaenoic acid methyl ester from microalgae.« less

Optimization of one-step in situ transesterification method for accurate quantification of EPA in Nannochloropsis gaditana

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

Tang, Yuting; Zhang, Yue; Rosenberg, Julian N.

Microalgae are a valuable source of lipid feedstocks for biodiesel and valuable omega-3 fatty acids. Nannochloropsis gaditana has emerged as a promising producer of eicosapentaenoic acid (EPA) due to its fast growth rate and high EPA content. In the present study, the fatty acid profile of Nannochloropsis gaditana was found to be naturally high in EPA and devoid of docosahexaenoic acid (DHA), thereby providing an opportunity to maximize the efficacy of EPA production. Using an optimized one-step in situ transesterification method (methanol:biomass = 90 mL/g; HCl 5% by vol.; 70 °C; 1.5 h), the maximum fatty acid methyl ester (FAME)more » yield of Nannochloropsis gaditana cultivated under rich condition was quantified as 10.04% ± 0.08% by weight with EPA-yields as high as 4.02% ± 0.17% based on dry biomass. The total FAME and EPA yields were 1.58- and 1.23-fold higher separately than that obtained using conventional two-step method (solvent system: methanol and chloroform). Furthermore, this one-step in situ method provides a fast and simple method to measure fatty acid methyl ester (FAME) yields and could serve as a promising method to generate eicosapentaenoic acid methyl ester from microalgae.« less

Combinatorial life cycle assessment to inform process design of industrial production of algal biodiesel.

PubMed

Brentner, Laura B; Eckelman, Matthew J; Zimmerman, Julie B

2011-08-15

The use of algae as a feedstock for biodiesel production is a rapidly growing industry, in the United States and globally. A life cycle assessment (LCA) is presented that compares various methods, either proposed or under development, for algal biodiesel to inform the most promising pathways for sustainable full-scale production. For this analysis, the system is divided into five distinct process steps: (1) microalgae cultivation, (2) harvesting and/or dewatering, (3) lipid extraction, (4) conversion (transesterification) into biodiesel, and (5) byproduct management. A number of technology options are considered for each process step and various technology combinations are assessed for their life cycle environmental impacts. The optimal option for each process step is selected yielding a best case scenario, comprised of a flat panel enclosed photobioreactor and direct transesterification of algal cells with supercritical methanol. For a functional unit of 10 GJ biodiesel, the best case production system yields a cumulative energy demand savings of more than 65 GJ, reduces water consumption by 585 m(3) and decreases greenhouse gas emissions by 86% compared to a base case scenario typical of early industrial practices, highlighting the importance of technological innovation in algae processing and providing guidance on promising production pathways.

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.

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.

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.

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.

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%.

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.

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.

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.

Enzymatic transesterification of waste vegetable oil to produce biodiesel.

PubMed

Lopresto, C G; Naccarato, S; Albo, L; De Paola, M G; Chakraborty, S; Curcio, S; Calabrò, V

2015-11-01

An experimental study on enzymatic transesterification was performed to produce biodiesel from waste vegetable oils. Lipase from Pseudomonas cepacia was covalently immobilized on a epoxy-acrylic resin support. The immobilized enzyme exhibited high catalytic specific surface and allowed an easy recovery, regeneration and reutilisation of biocatalyst. Waste vegetable oils - such as frying oils, considered not competitive with food applications and wastes to be treated - were used as a source of glycerides. Ethanol was used as a short chain alcohol and was added in three steps with the aim to reduce its inhibitory effect on lipase activity. The effect of biocatalyst/substrate feed mass ratios and the waste oil quality have been investigated in order to estimate the process performances. Biocatalyst recovery and reuse have been also studied with the aim to verify the stability of the biocatalyst for its application in industrial scale. Copyright © 2015 Elsevier Inc. All rights reserved.

Lipase-catalyzed transesterification of soybean oil and phytosterol in supercritical CO2.

PubMed

Hu, Lizhi; Llibin, Sun; Li, Jun; Qi, Liangjun; Zhang, Xu; Yu, Dianyu; Walid, Elfalleh; Jiang, Lianzhou

2015-12-01

The transesterification of phytosterol and soybean oil was performed using Novozym 435 in supercritical carbon dioxide (SC-CO2). The transesterification reaction was conducted in soybean oil containing 5-25% phytosterol at 55-95 °C and free-water solvent. The effects of temperature, reaction time, phytosterol concentration, lipase dosage and reaction pressure on the conversion rate of transesterification were investigated. The optimal reaction conditions were the reaction temperature (85 °C), reaction time (1 h), phytosterol concentration (5%), reaction pressure (8 Mpa) and lipase dosage (1%). The highest conversion rate of 92% could be achieved under the optimum conditions. Compared with the method of lipase-catalyzed transesterification of phytosterol and soybean oil at normal pressure, the transesterification in SC-CO2 reduced significantly the reaction temperature and reaction time.

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.

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.

Structure-property studies of thermoplastic and thermosetting polyurethanes using palm and soya oils-based polyols.

PubMed

Mohammed, Issam Ahmed; Al-Mulla, Emad Abbas Jaffar; Kadar, Nurul Khizien Abdul; Ibrahim, Mazlan

2013-01-01

Palm and soya oils were converted to monoglycerides via transesterification of triglycerides with glycerol by one step process to produce renewable polyols. Thermoplastic polyurethanes (TPPUs) were prepared from the reaction of the monoglycerides which act as polyol with 4,4'-methylenediphenyldiisocyanate (MDI) whereas, thermosetting polyurethanes (TSPUs) were prepared from the reaction of glycerol, MDI and monoglycerides in one pot. Characterization of the polyurethanes was carried out by FT-IR, (1)H NMR, and iodine value and sol-gel fraction. The TSPUs showed good thermal properties compared to TPPUs as well as TSPUs exhibits good properties in pencil hardness and adhesion, however poorer in flexural and impact strength compared to TPPUs. The higher percentage of cross linked fraction, the higher degree of cross linking occurred, which is due to the higher number of double bond presents in the TSPUs. These were reflected in iodine value test as the highest iodine value of the soya-based thermosetting polyurethanes confirmed the highest degree of cross linking. Polyurethanes based on soya oil showed better properties compared to palm oil. This study is a breakthrough development of polyurethane resins using palm and soya oils as one of the raw materials.

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 %.

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.

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.

Biodiesel production by two-stage transesterification with ethanol by washing with neutral water and water saturated with carbon dioxide.

PubMed

Mendow, G; Veizaga, N S; Sánchez, B S; Querini, C A

2012-08-01

Industrial production of ethyl esters is impeded by difficulties in purifying the product due to high amounts of soap formed during transesterification. A simple biodiesel wash process was developed that allows successful purification of samples containing high amounts of soap. The key step was a first washing with neutral water, which removed the soaps without increasing the acidity or affecting the process yield. Afterward, the biodiesel was washed with water saturated with CO(2), a mild acid that neutralized the remaining soaps and extracted impurities. The acidity, free-glycerine, methanol and soaps concentrations were reduced to very low levels with high efficiency, and using non-corrosive acids. Independently of the initial acidity, it was possible to obtain biodiesel within EN14214 specifications. The process included the recovery of soaps by hydrolysis and esterification, making it possible to obtain the theoretical maximum amount of biodiesel. Copyright © 2012 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.

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

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.

Effect on the use of ultrasonic cavitation for biodiesel production from crued Jatropha curcas L. seed oil with a high content of free fatty acid

NASA Astrophysics Data System (ADS)

Worapun, Ittipon; Pianthong, Kulachate; Thaiyasuit, Prachasanti; Thinvongpituk, Chawalit

2010-03-01

A typical way to produce biodiesel is the transesterification of plant oils. This is commonly carried out by treating the pre-extracted oil with an appropriate alcohol in the presence of an acidic or alkaline catalyst over one or two hours in a batch reactor.Because oils and methanol are not completely miscible. It has been widely demonstrated that low-frequency ultrasonic irradiation is an effective tool for emulsifying immiscible liquids. The objective of this research is to investigate the optimum conditions for biodiesel production from crude Jatropha curcas oil with short chain alcohols by ultrasonic cavitation (at 40 kHz frequency and 400 Watt) assisted, using two step catalyst method. Usually, the crude Jatropha curcas oil has very high free fatty acid which obstructs the transesterification reaction. As a result it provides low yield of biodiesel production. In the first step, the reaction was carried out in the presence of sulfuric acid as an acid catalyst. The product was then further transesterified with potassium hydroxide in the second step. The effects of different operating parameters such as molar ratio of reactants, catalyst quantity, and operating temperature, have been studied with the aim of process optimization. It has been observed that the mass transfer and kinetic rate enhancements were due to the increase in interfacial area and activity of the microscopic and macroscopic bubbles formed. For example, the product yield levels of more than 90% have been observed with the use of ultrasonic cavitation in about 60 minutes under room temperature operating conditions.

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.

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.

Ionic liquids as transesterification catalysts: applications for the synthesis of linear and cyclic organic carbonates

PubMed Central

Perosa, Alvise; Guidi, Sandro; Cattelan, Lisa

2016-01-01

Summary The use of ionic liquids (ILs) as organocatalysts is reviewed for transesterification reactions, specifically for the conversion of nontoxic compounds such as dialkyl carbonates to both linear mono-transesterification products or alkylene carbonates. An introductory survey compares pros and cons of classic catalysts based on both acidic and basic systems, to ionic liquids. Then, innovative green syntheses of task-specific ILs and their representative applications are introduced to detail the efficiency and highly selective outcome of ILs-catalyzed transesterification reactions. A mechanistic hypothesis is discussed by the concept of cooperative catalysis based on the dual (electrophilic/nucleophilic) activation of reactants. PMID:27829898

Biodiesel production from wet microalgae feedstock using sequential wet extraction/transesterification and direct transesterification processes.

PubMed

Chen, Ching-Lung; Huang, Chien-Chang; Ho, Kao-Chia; Hsiao, Ping-Xuan; Wu, Meng-Shan; Chang, Jo-Shu

2015-10-01

Although producing biodiesel from microalgae seems promising, there is still a lack of technology for the quick and cost-effective conversion of biodiesel from wet microalgae. This study was aimed to develop a novel microalgal biodiesel producing method, consisting of an open system of microwave disruption, partial dewatering (via combination of methanol treatment and low-speed centrifugation), oil extraction, and transesterification without the pre-removal of the co-solvent, using Chlamydomonas sp. JSC4 with 68.7 wt% water content as the feedstock. Direct transesterification with the disrupted wet microalgae was also conducted. The biomass content of the wet microalgae increased to 56.6 and 60.5 wt%, respectively, after microwave disruption and partial dewatering. About 96.2% oil recovery was achieved under the conditions of: extraction temperature, 45°C; hexane/methanol ratio, 3:1; extraction time, 80 min. Transesterification of the extracted oil reached 97.2% conversion within 15 min at 45°C and 6:1 solvent/methanol ratio with simultaneous Chlorophyll removal during the process. Nearly 100% biodiesel conversion was also obtained while conducting direct transesterification of the disrupted oil-bearing microalgal biomass. Copyright © 2015 Elsevier Ltd. All rights reserved.

Pressure modulates the self-cleavage step of the hairpin ribozyme

NASA Astrophysics Data System (ADS)

Schuabb, Caroline; Kumar, Narendra; Pataraia, Salome; Marx, Dominik; Winter, Roland

2017-03-01

The ability of certain RNAs, denoted as ribozymes, to not only store genetic information but also catalyse chemical reactions gave support to the RNA world hypothesis as a putative step in the development of early life on Earth. This, however, might have evolved under extreme environmental conditions, including the deep sea with pressures in the kbar regime. Here we study pressure-induced effects on the self-cleavage of hairpin ribozyme by following structural changes in real-time. Our results suggest that compression of the ribozyme leads to an accelerated transesterification reaction, being the self-cleavage step, although the overall process is retarded in the high-pressure regime. The results reveal that favourable interactions between the reaction site and neighbouring nucleobases are strengthened under pressure, resulting therefore in an accelerated self-cleavage step upon compression. These results suggest that properly engineered ribozymes may also act as piezophilic biocatalysts in addition to their hitherto known properties.

Imperata cylindrica sp as Novel Silica-Based Heterogeneous Catalysts for Transesterification of Palm Oil Mill Sludge.

PubMed

Ngaini, Zainab; Shahrom, Farra Diana; Jamil, Nurfarahen; Wahi, Rafeah; Ahmad, Zainal Abiddin

2016-06-01

Biodiesel from palm oil mill sludge (POMS) was prepared in the presence of novel silica-based heterogeneous catalysts derived from Imperata cylindrica sp. Imperatacid and Imperatabase are two types of heterogeneous catalysts derived from Imperata cylindrica sp and characterized using scanning electron microscopy, Energy Dispersive X-ray, Brunauer-Emmett-Teller surface area and pore size measurement. Imperatacid has particle size of 43.1-83.9 µm while Imperatabase in the range of 89-193 µm. Imperatacid was conveniently applied in esterification step to afford > 90 wt% oil in 1:3 (oil/methanol) and 10 wt% catalyst, followed by transesterification with 1 wt% Imperatabase and 1:1 (oil/methanol) for 1 h at 65°C to afford 80% biodiesel with higher percentage of methyl palmitate (48.97%) and methyl oleate (34.14%) compare to conventional homogeneous catalyst. Reusability of the catalyst up to three times afforded biodiesel ranging from 78-80% w/w. The biodiesel was demonstrated onto alternative diesel engine (Megatech(®)-Mark III) and showed proportional increased of torque (ɽ) to biodiesel loading.

Conversion of solid organic wastes into oil via Boettcherisca peregrine (Diptera: Sarcophagidae) larvae and optimization of parameters for biodiesel production.

PubMed

Yang, Sen; Li, Qing; Zeng, Qinglan; Zhang, Jibin; Yu, Ziniu; Liu, Ziduo

2012-01-01

The feedstocks for biodiesel production are predominantly from edible oils and the high cost of the feedstocks prevents its large scale application. In this study, we evaluated the oil extracted from Boettcherisca peregrine larvae (BPL) grown on solid organic wastes for biodiesel production. The oil contents detected in the BPL converted from swine manure, fermentation residue and the degreased food waste, were 21.7%, 19.5% and 31.1%, respectively. The acid value of the oil is 19.02 mg KOH/g requiring a two-step transesterification process. The optimized process of 12∶1 methanol/oil (mol/mol) with 1.5% H(2)SO(4) reacted at 70°C for 120 min resulted in a 90.8% conversion rate of free fatty acid (FFA) by esterification, and a 92.3% conversion rate of triglycerides into esters by alkaline transesterification. Properties of the BPL oil-based biodiesel are within the specifications of ASTM D6751, suggesting that the solid organic waste-grown BPL could be a feasible non-food feedstock for biodiesel production.

Conversion of Solid Organic Wastes into Oil via Boettcherisca peregrine (Diptera: Sarcophagidae) Larvae and Optimization of Parameters for Biodiesel Production

PubMed Central

Yang, Sen; Li, Qing; Zeng, Qinglan; Zhang, Jibin; Yu, Ziniu; Liu, Ziduo

2012-01-01

The feedstocks for biodiesel production are predominantly from edible oils and the high cost of the feedstocks prevents its large scale application. In this study, we evaluated the oil extracted from Boettcherisca peregrine larvae (BPL) grown on solid organic wastes for biodiesel production. The oil contents detected in the BPL converted from swine manure, fermentation residue and the degreased food waste, were 21.7%, 19.5% and 31.1%, respectively. The acid value of the oil is 19.02 mg KOH/g requiring a two-step transesterification process. The optimized process of 12∶1 methanol/oil (mol/mol) with 1.5% H2SO4 reacted at 70°C for 120 min resulted in a 90.8% conversion rate of free fatty acid (FFA) by esterification, and a 92.3% conversion rate of triglycerides into esters by alkaline transesterification. Properties of the BPL oil-based biodiesel are within the specifications of ASTM D6751, suggesting that the solid organic waste-grown BPL could be a feasible non-food feedstock for biodiesel production. PMID:23029331

Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base difunctional catalysts for transesterification.

PubMed

Zeng, Ruijie; Sheng, Hongting; Zhang, Yongcang; Feng, Yan; Chen, Zhi; Wang, Junfeng; Chen, Man; Zhu, Manzhou; Guo, Qingxiang

2014-10-03

A practical lanthanide(III)-catalyzed transesterification of carboxylic esters, weakly reactive carbonates, and much less-reactive ethyl silicate with primary and secondary alcohols was developed. Heterobimetallic dinuclear lanthanide alkoxide complexes [Ln2Na8{(OCH2CH2NMe2)}12(OH)2] (Ln = Nd (I), Sm (II), and Yb (III)) were used as highly active catalysts for this reaction. The mild reaction conditions enabled the transesterification of various substrates to proceed in good to high yield. Efficient activation of transesterification may be endowed by the above complexes as cooperative acid-base difunctional catalysts, which is proposed to be responsible for the higher reactivity in comparison with simple acid/base catalysts.

Effect of metal ions on the hydrolytic and transesterification activities of Candida rugosa lipase.

PubMed

Katiyar, Madhu; Ali, Amjad

2013-01-01

In order to study the effect of metal ions on lipase activity, hydrolytic and transesterification activities of Candida rugosa lipase were investigated in presence of alkali (Na⁺ and K⁺), alkaline earth (Ca⁺² and Ba⁺²) and transition (Cr⁺³, Fe⁺³, Co⁺², Cu⁺² and Ni⁺²) metal ions. Maximum enhancement in hydrolytic activity of lipase was observed by Ca⁺², and in transesterification activity by Cr⁺³ and Co⁺². The kinetics of the lipase catalyzed transesterification (methanolysis and ethanolysis) reactions were also studied, and the activation energies of methanolysis and ethanolysis were reduced from 10.16 and 10.24 kcal mol⁻¹, respectively, to 5.41 and 7.55 kcal mol⁻¹, respectively, when reactions were performed in presence of Co⁺². Thus, in lipase catalyzed transesterification Cr⁺³ or Co⁺² could be added to the assay in order to produce the biodiesel in relatively shorter reaction duration.

In-situ pyrogenic production of biodiesel from swine fat.

PubMed

Lee, Jechan; Tsang, Yiu Fai; Jung, Jong-Min; Oh, Jeong-Ik; Kim, Hyung-Wook; Kwon, Eilhann E

2016-11-01

In-situ production of fatty acid methyl esters from swine fat via thermally induced pseudo-catalytic transesterification on silica was investigated in this study. Instead of methanol, dimethyl carbonate (DMC) was used as acyl acceptor to achieve environmental benefits and economic viability. Thermo-gravimetric analysis of swine fat reveals that swine fat contains 19.57wt.% of water and impurities. Moreover, the fatty acid profiles obtained under various conditions (extracted swine oil+methanol+NaOH, extracted swine oil+DMC+pseudo-catalytic, and swine fat+DMC+pseudo-catalytic) were compared. These profiles were identical, showing that the introduced in-situ transesterification is technically feasible. This also suggests that in-situ pseudo-catalytic transesterification has a high tolerance against impurities. This study also shows that FAME yield via in-situ pseudo-catalytic transesterification of swine fat reached up to 97.2% at 380°C. Therefore, in-situ pseudo-catalytic transesterification can be applicable to biodiesel production of other oil-bearing biomass feedstocks. Copyright © 2016 Elsevier Ltd. All rights reserved.

Wet in situ transesterification of microalgae using ethyl acetate as a co-solvent and reactant.

PubMed

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

2017-04-01

This study addresses wet in situ transesterification of microalgae for the production of biodiesel by introducing ethyl acetate as both reactant and co-solvent. Ethyl acetate and acid catalyst are mixed with wet microalgae in one pot and the mixture is heated for simultaneous lipid extraction and transesterification. As a single reactant and co-solvent, ethyl acetate can provide higher FAEE yield and more saccharification of carbohydrates than the case of binary ethanol and chloroform as a reactant and a co-solvent. The optimal yield was 97.8wt% at 114°C and 4.06M catalyst with 6.67mlEtOAC/g dried algae based on experimental results and response surface methodology (RSM). This wet in situ transesterification of microalgae using ethyl acetate doesn't require an additional co-solvent and it also promises more economic benefit as combining extraction and transesterification in a single process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Fast transmethylation of serum lipids using microwave irradiation.

PubMed

Lin, Yu Hong; Loewke, James D; Hyun, Duk Y; Leazer, Jay; Hibbeln, Joseph R

2012-11-01

Microwave irradiation as the energy source for one-step direct transesterification of fatty acids in human serum lipids was examined in a solvent system of methanol: hexane: acetyl chloride based on a Lepage & Roy assay. Innovative and explosion proof single-mode or multimode microwave accelerated reaction system was employed. Recoveries were calculated as the percentage of fatty acid concentrations measured by microwave assay to those by the reference method of the Lepage & Roy assay that utilized conductive heating at 100 °C for 60 min. Under conditions of 100 °C for 1 min in Single-mode (S4-100 × 1), or 125 °C for 5 min in Multimode (M5-125 × 5), the recoveries were 100-103 % for the total fatty acids and 96-106 % for each categorized fatty acid, including saturates, monounsaturates, n-6 PUFA, and n-3 PUFA. For individual PUFA, the mean recoveries were 102-105 % for 18:2n-6 and 18:3n-3; 99, 109, and 95 % for 20:4n-6, 20:5n-3, and 22:6n-3, respectively. Thus, fatty acid concentrations determined by microwave fatty acid assay were accurate to those results by the reference method, when the microwave conditions were optimal. In summary, the microwave irradiation could replace conductive heating in one-step direct transesterification, and reduce the duration from 60 min to 5 min or less. This methodology may be applied in both the absolute and relative quantification of serum total fatty acids.

Fast Transmethylation of Serum Lipids using Microwave Irradiation

PubMed Central

Lin, Yu Hong; Loewke, James D.; Hyun, Duk Y.; Leazer, Jay; Hibbeln, Joseph R.

2012-01-01

Microwave irradiation as the energy source for one–step direct transesterification of fatty acids in human serum lipids was examined in solvent system of methanol: hexane: acetyl chloride based on Lepage & Roy assay. Innovative and explosion proof single–mode or multimode microwave accelerate reaction system was employed. Recoveries were calculated as the percentage of fatty acid concentrations measured by microwave assay to those by reference method Lepage & Roy assay that utilized conductive heating at 100 °C for 60 min. At conditions of 100 °C for 1 min in Single–mode (S4–100×1), or 125 °C for 5 min in Multimode (M5–125×5), the recoveries were 100–103% for the total fatty acids and 96–106% for each categorized fatty acid, including saturates, monounsaturates, n-6 PUFA, and n-3 PUFA. For individual PUFA, the mean recoveries were 102–105% for 18:2n-6 and 18:3n-3; 99, 109, and 95% for 20:4n-6, 20:5n-3, and 22:6n-3, respectively. Thus, fatty acid concentrations determined by microwave fatty acid assay were accurate to those results by the reference method, when the microwave conditions were optimal. In summary, the microwave irradiation could replace conductive heating in one–step direct transesterification, and reduce duration from 60 min to 5 min or less. This methodology may be applied in both the absolute and relative quantification of serum total fatty acids. PMID:23015312

Determination of fatty acid methyl esters derived from algae Scenedesmus dimorphus biomass by GC-MS with one-step esterification of free fatty acids and transesterification of glycerolipids.

PubMed

Avula, Satya Girish Chandra; Belovich, Joanne M; Xu, Yan

2017-05-01

Algae can synthesize, accumulate and store large amounts of lipids in its cells, which holds immense potential as a renewable source of biodiesel. In this work, we have developed and validated a GC-MS method for quantitation of fatty acids and glycerolipids in forms of fatty acid methyl esters derived from algae biomass. Algae Scenedesmus dimorphus dry mass was pulverized by mortar and pestle, then extracted by the modified Folch method and fractionated into free fatty acids and glycerolipids on aminopropyl solid-phase extraction cartridges. Fatty acid methyl esters were produced by an optimized one-step esterification of fatty acids and transesterification of glycerolipids with boron trichloride/methanol. The matrix effect, recoveries and stability of fatty acids and glycerolipids in algal matrix were first evaluated by spiking stable isotopes of pentadecanoic-2,2-d 2 acid and glyceryl tri(hexadecanoate-2,2-d 2 ) as surrogate analytes and tridecanoic-2,2-d 2 acid as internal standard into algal matrix prior to sample extraction. Later, the method was validated in terms of lower limits of quantitation, linear calibration ranges, intra- and inter-assay precision and accuracy using tridecanoic-2,2-d 2 acid as internal standard. The method developed has been applied to the quantitation of fatty acid methyl esters from free fatty acid and glycerolipid fractions of algae Scenedesmus dimorphus. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Fluorescent microplate assay method for high-throughput detection of lipase transesterification activity.

PubMed

Zheng, Jianyong; Wei, Wei; Lan, Xing; Zhang, Yinjun; Wang, Zhao

2018-05-15

This study describes a sensitive and fluorescent microplate assay method to detect lipase transesterification activity. Lipase-catalyzed transesterification between butyryl 4-methyl umbelliferone (Bu-4-Mu) and methanol in tert-butanol was selected as the model reaction. The release of 4-methylumbelliferone (4-Mu) in the reaction was determined by detecting the fluorescence intensity at λ ex 330 nm and λ em 390 nm. Several lipases were used to investigate the accuracy and efficiency of the proposed method. Apparent Michaelis constant (Km) was calculated for transesterification between Bu-4-Mu and methanol by the lipases. The main advantages of the assay method include high sensitivity, inexpensive reagents, and simple detection process. Copyright © 2018 Elsevier Inc. All rights reserved.

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.

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).

RNA splicing process analysis for identifying antisense oligonucleotide inhibitors with padlock probe-based isothermal amplification.

PubMed

Ren, Xiaojun; Deng, Ruijie; Wang, Lida; Zhang, Kaixiang; Li, Jinghong

2017-08-01

RNA splicing, which mainly involves two transesterification steps, is a fundamental process of gene expression and its abnormal regulation contributes to serious genetic diseases. Antisense oligonucleotides (ASOs) are genetic control tools that can be used to specifically control genes through alteration of the RNA splicing pathway. Despite intensive research, how ASOs or various other factors influence the multiple processes of RNA splicing still remains obscure. This is largely due to an inability to analyze the splicing efficiency of each step in the RNA splicing process with high sensitivity. We addressed this limitation by introducing a padlock probe-based isothermal amplification assay to achieve quantification of the specific products in different splicing steps. With this amplified assay, the roles that ASOs play in RNA splicing inhibition in the first and second steps could be distinguished. We identified that 5'-ASO could block RNA splicing by inhibiting the first step, while 3'-ASO could block RNA splicing by inhibiting the second step. This method provides a versatile tool for assisting efficient ASO design and discovering new splicing modulators and therapeutic drugs.

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.

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

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

Escherichia coli as a fatty acid and biodiesel factory: current challenges and future directions.

PubMed

Rahman, Ziaur; Rashid, Naim; Nawab, Javed; Ilyas, Muhammad; Sung, Bong Hyun; Kim, Sun Chang

2016-06-01

Biodiesel has received widespread attention as a sustainable, environment-friendly, and alternative source of energy. It can be derived from plant, animal, and microbial organisms in the form of vegetable oil, fats, and lipids, respectively. However, biodiesel production from such sources is not economically feasible due to extensive downstream processes, such as trans-esterification and purification. To obtain cost-effective biodiesel, these bottlenecks need to be overcome. Escherichia coli, a model microorganism, has the potential to produce biodiesel directly from ligno-cellulosic sugars, bypassing trans-esterification. In this process, E. coli is engineered to produce biodiesel using metabolic engineering technology. The entire process of biodiesel production is carried out in a single microbial cell, bypassing the expensive downstream processing steps. This review focuses mainly on production of fatty acid and biodiesel in E. coli using metabolic engineering approaches. In the first part, we describe fatty acid biosynthesis in E. coli. In the second half, we discuss bottlenecks and strategies to enhance the production yield. A complete understanding of current developments in E. coli-based biodiesel production and pathway optimization strategies would reduce production costs for biofuels and plant-derived chemicals.

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.

Experimental assessment of non-edible candlenut biodiesel and its blend characteristics as diesel engine fuel.

PubMed

Imdadul, H K; Zulkifli, N W M; Masjuki, H H; Kalam, M A; Kamruzzaman, M; Rashed, M M; Rashedul, H K; Alwi, Azham

2017-01-01

Exploring new renewable energy sources as a substitute of petroleum reserves is necessary due to fulfilling the oncoming energy needs for industry and transportation systems. In this quest, a lot of research is going on to expose different kinds of new biodiesel sources. The non-edible oil from candlenut possesses the potential as a feedstock for biodiesel production. The present study aims to produce biodiesel from crude candlenut oil by using two-step transesterification process, and 10%, 20%, and 30% of biodiesel were mixed with diesel fuel as test blends for engine testing. Fourier transform infrared (FTIR) and gas chromatography (GC) were performed and analyzed to characterize the biodiesel. Also, the fuel properties of biodiesel and its blends were measured and compared with the specified standards. The thermal stability of the fuel blends was measured by thermogravimetric analysis (TGA) and differential scan calorimetry (DSC) analysis. Engine characteristics were measured in a Yanmar TF120M single cylinder direct injection (DI) diesel engine. Biodiesel produced from candlenut oil contained 15% free fatty acid (FFA), and two-step esterification and transesterification were used. FTIR and GC remarked the biodiesels' existing functional groups and fatty acid methyl ester (FAME) composition. The thermal analysis of the biodiesel blends certified about the blends' stability regarding thermal degradation, melting and crystallization temperature, oxidative temperature, and storage stability. The brake power (BP), brake specific fuel consumption (BSFC), and brake thermal efficiency (BTE) of the biodiesel blends decreased slightly with an increasing pattern of nitric oxide (NO) emission. However, the hydrocarbon (HC) and carbon monoxides (CO) of biodiesel blends were found decreased.

One-step synthesis of high-yield biodiesel from waste cooking oils by a novel and highly methanol-tolerant immobilized lipase.

PubMed

Wang, Xiumei; Qin, Xiaoli; Li, Daoming; Yang, Bo; Wang, Yonghua

2017-07-01

This study reported a novel immobilized MAS1 lipase from marine Streptomyces sp. strain W007 for synthesizing high-yield biodiesel from waste cooking oils (WCO) with one-step addition of methanol in a solvent-free system. Immobilized MAS1 lipase was selected for the transesterification reactions with one-step addition of methanol due to its much more higher biodiesel yield (89.50%) when compared with the other three commercial immobilized lipases (<10%). The highest biodiesel yield (95.45%) was acquired with one-step addition of methanol under the optimized conditions. Moreover, it was observed that immobilized MAS1 lipase retained approximately 70% of its initial activity after being used for four batch cycles. Finally, the obtained biodiesel was further characterized using FT-IR, 1 H and 13 C NMR spectroscopy. These findings indicated that immobilized MAS1 lipase is a promising catalyst for biodiesel production from WCO with one-step addition of methanol under high methanol concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Protein-DNA interactions define the mechanistic aspects of circle formation and insertion reactions in IS2 transposition.

PubMed

Lewis, Leslie A; Astatke, Mekbib; Umekubo, Peter T; Alvi, Shaheen; Saby, Robert; Afrose, Jehan; Oliveira, Pedro H; Monteiro, Gabriel A; Prazeres, Duarte Mf

2012-01-26

Transposition in IS3, IS30, IS21 and IS256 insertion sequence (IS) families utilizes an unconventional two-step pathway. A figure-of-eight intermediate in Step I, from asymmetric single-strand cleavage and joining reactions, is converted into a double-stranded minicircle whose junction (the abutted left and right ends) is the substrate for symmetrical transesterification attacks on target DNA in Step II, suggesting intrinsically different synaptic complexes (SC) for each step. Transposases of these ISs bind poorly to cognate DNA and comparative biophysical analyses of SC I and SC II have proven elusive. We have prepared a native, soluble, active, GFP-tagged fusion derivative of the IS2 transposase that creates fully formed complexes with single-end and minicircle junction (MCJ) substrates and used these successfully in hydroxyl radical footprinting experiments. In IS2, Step I reactions are physically and chemically asymmetric; the left imperfect, inverted repeat (IRL), the exclusive recipient end, lacks donor function. In SC I, different protection patterns of the cleavage domains (CDs) of the right imperfect inverted repeat (IRR; extensive in cis) and IRL (selective in trans) at the single active cognate IRR catalytic center (CC) are related to their donor and recipient functions. In SC II, extensive binding of the IRL CD in trans and of the abutted IRR CD in cis at this CC represents the first phase of the complex. An MCJ substrate precleaved at the 3' end of IRR revealed a temporary transition state with the IRL CD disengaged from the protein. We propose that in SC II, sequential 3' cleavages at the bound abutted CDs trigger a conformational change, allowing the IRL CD to complex to its cognate CC, producing the second phase. Corroborating data from enhanced residues and curvature propensity plots suggest that CD to CD interactions in SC I and SC II require IRL to assume a bent structure, to facilitate binding in trans. Different transpososomes are assembled in each step of the IS2 transposition pathway. Recipient versus donor end functions of the IRL CD in SC I and SC II and the conformational change in SC II that produces the phase needed for symmetrical IRL and IRR donor attacks on target DNA highlight the differences.

Protein-DNA interactions define the mechanistic aspects of circle formation and insertion reactions in IS2 transposition

PubMed Central

2012-01-01

Background Transposition in IS3, IS30, IS21 and IS256 insertion sequence (IS) families utilizes an unconventional two-step pathway. A figure-of-eight intermediate in Step I, from asymmetric single-strand cleavage and joining reactions, is converted into a double-stranded minicircle whose junction (the abutted left and right ends) is the substrate for symmetrical transesterification attacks on target DNA in Step II, suggesting intrinsically different synaptic complexes (SC) for each step. Transposases of these ISs bind poorly to cognate DNA and comparative biophysical analyses of SC I and SC II have proven elusive. We have prepared a native, soluble, active, GFP-tagged fusion derivative of the IS2 transposase that creates fully formed complexes with single-end and minicircle junction (MCJ) substrates and used these successfully in hydroxyl radical footprinting experiments. Results In IS2, Step I reactions are physically and chemically asymmetric; the left imperfect, inverted repeat (IRL), the exclusive recipient end, lacks donor function. In SC I, different protection patterns of the cleavage domains (CDs) of the right imperfect inverted repeat (IRR; extensive in cis) and IRL (selective in trans) at the single active cognate IRR catalytic center (CC) are related to their donor and recipient functions. In SC II, extensive binding of the IRL CD in trans and of the abutted IRR CD in cis at this CC represents the first phase of the complex. An MCJ substrate precleaved at the 3' end of IRR revealed a temporary transition state with the IRL CD disengaged from the protein. We propose that in SC II, sequential 3' cleavages at the bound abutted CDs trigger a conformational change, allowing the IRL CD to complex to its cognate CC, producing the second phase. Corroborating data from enhanced residues and curvature propensity plots suggest that CD to CD interactions in SC I and SC II require IRL to assume a bent structure, to facilitate binding in trans. Conclusions Different transpososomes are assembled in each step of the IS2 transposition pathway. Recipient versus donor end functions of the IRL CD in SC I and SC II and the conformational change in SC II that produces the phase needed for symmetrical IRL and IRR donor attacks on target DNA highlight the differences. PMID:22277150

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.

Diels-Alder cycloaddition in the synthesis of 1-azafagomine, analogs, and derivatives as glycosidase inhibitors.

PubMed

Salgueiro, Daniela A L; Sousa, Cristina E A; Fortes, A Gil; Alves, M José

2012-12-01

This comprehensive review deals with the synthesis of 1-azafagomine, analogs, and derivatives having the Diels-Alder cycloaddition as the key step. Most of the compounds referred are racemic or have been resolved by lipase transesterification. There are two asymmetric cycloadditions leading to 1-azafagomine or to an analog. In one case both enantiomers of 1-azafagomine were prepared together with a pair of derivatives. The study comprises glycosidase inhibition studies of the target compounds to a set of glycosidic enzymes, and evidenced molecular features that enhance or diminish their activity as glycosidase inhibitors.

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.

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.

Medium-chain alkyl esters of tyrosol and hydroxytyrosol antioxidants by cuphea oil transesterification

USDA-ARS?s Scientific Manuscript database

Effective lipophilic antioxidants were readily prepared by non-aqueous enzymatic transesterification of plant phenols with cuphea oil. Tyrosol (2-(4-hydroxyphenyl)ethanol) and hydroxytyrosol (2-(3,4-dihydroxyphenyl)ethanol), abundantly available phenols from olive oil processing byproduct, were foun...

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.

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.

In-situ transesterification of wet spent coffee grounds for sustainable biodiesel production.

PubMed

Park, Jeongseok; Kim, Bora; Lee, Jae W

2016-12-01

This work addresses in-situ transesterification of wet spent coffee grounds (SCGs) for the production of biodiesel. For in-situ transesterification process, the methanol, organic solvent and acid catalyst were mixed with wet SCG in one pot and the mixture was heated for simultaneous lipid extraction and transesterification. Maximum yield of fatty acid methyl esters (FAME) was 16.75wt.% based on the weight of dry SCG at 95°C. Comprehensive experiments were conducted with varying temperatures and various amounts of moisture, methanol, co-solvent and acid catalyst. Moderate polar and alcohol-miscible organic solvent is suitable for the high FAME yield. Unsaturated FAMEs are subject to oxidative cleavage by nitric acid and shorter chain (C6 and C10) FAMEs were mainly produced while sulfuric acid yielded long chain unsaturated FAMEs (C16 and C18). Utilization of wet SCGs as a biodiesel feedstock gives economic and environmental benefits by recycling the municipal waste. Copyright © 2016 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.

Process design of in situ esterification-transesterifica tion for biodiesel production from residual oil of spent bleaching earth (SBE)

NASA Astrophysics Data System (ADS)

Suryani, A.; Mubarok, Z.; Suprihatin; Romli, M.; Yunira, E. N.

2017-05-01

Indonesia is the largest producer of Crude Palm Oil (CPO) in the world. CPO refining process produces spent bleaching earth (SBE), which still contains 20-30% oil. This residual oil is very potential to be developed as a biodiesel feedstock. The purpose of this research was to develop an in situbiodiesel production process of residual oil of SBE, which covered stirring speed of esterification and transesterification and also transesterification time to produce biodiesel with the best characteristics. The production was conducted in a 100 L reactor. The stirring speeds applied were 650 rpm and 730 rpm, and the transesterification time varied at 60, 90 and 120 minutes. The combination of 730 rpm stirring speed for 90 minutes transesterification resulted in the best biodiesel characteristics with the yield of 85%, the specific energy of 6,738 kJ/kg and the heater efficiency of 48%. The physico-chemical properties of biodiesel was in conformity with the SNI of Biodiesel.

Enzymatic transesterification of microalgal oil from Chlorella vulgaris ESP-31 for biodiesel synthesis using immobilized Burkholderia lipase.

PubMed

Tran, Dang-Thuan; Yeh, Kuei-Ling; Chen, Ching-Lung; Chang, Jo-Shu

2012-03-01

An indigenous microalga Chlorella vulgaris ESP-31 grown in an outdoor tubular photobioreactor with CO(2) aeration obtained a high oil content of up to 63.2%. The microalgal oil was then converted to biodiesel by enzymatic transesterification using an immobilized lipase originating from Burkholderia sp. C20. The conversion of the microalgae oil to biodiesel was conducted by transesterification of the extracted microalgal oil (M-I) and by transesterification directly using disrupted microalgal biomass (M-II). The results show that M-II achieved higher biodiesel conversion (97.3 wt% oil) than M-I (72.1 wt% oil). The immobilized lipase worked well when using wet microalgal biomass (up to 71% water content) as the oil substrate. The immobilized lipase also tolerated a high methanol to oil molar ratio (>67.93) when using the M-II approach, and can be repeatedly used for six cycles (or 288 h) without significant loss of its original activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

[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.

Optimization of sodium loading on zeolite support for catalyzed transesterification of triolein with methanol.

PubMed

Wang, Yu-Yuan; Chou, Hsin-Yu; Chen, Bing-Hung; Lee, Duu-Jong

2013-10-01

Optimization of sodium loading on zeolite HY for catalyzed transesterification of triolein in excess methanol to biodiesel was studied. Zeolite HY catalyst was activated by loading sodium ions to their surface via an ion-exchange method. The effects of ion-exchange process parameters, including the temperature, the process time, the pH value, as well as concentrations and sources of Na(+) cations (NaOH, NaCl and Na2SO4), on the conversion yield of triolein to biodiesel were investigated. Most of these Na(+)-activated zeolite HY catalysts could really facilitate the catalyzed transesterification reaction of triolein to biodiesel at a lower temperature near 65°C. Consequently, a high conversion yield of triglycerides to biodiesel at 97.3% was obtained at 65°C. Moreover, the durability of zeolite catalysts was examined as well. Catalytic performance tests of these zeolite catalysts in transesterification did not show a significant decrease in catalysis at least for three batch cycles. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

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.

Step-doubling at Vicinal Ni(111) Surfaces Investigated with a Curved Crystal

DOE PAGES

Ilyn, Max; Magana, Ana; Walter, Andrew Leigh; ...

2017-01-25

Here, vicinal surfaces may undergo structural transformations as a function of temperature or in the presence of adsorbates. Step-doubling, in which monatomic steps pair up forming double-atom high staircases, is the simplest example. Here we investigate the case of Ni(111) using a curved crystal surface, which allows us to explore the occurrence of step-doubling as a function of temperature and vicinal plane (miscut α and step type). We find a striking A-type ({100}-like microfacets) versus B-type ({111}-like) asymmetry towards step-doubling. The terrace-width distribution analysis performed from Scanning Tunneling Microscopy data points to elastic step interactions overcoming entropic effects at verymore » small miscut α in A-type vicinals, as compared to B-type steps. For A-type vicinals, we elaborate the temperature/miscut phase diagram, on which we establish a critical miscut α c = 9.3° for step-doubling to take place.« less

Step-doubling at Vicinal Ni(111) Surfaces Investigated with a Curved Crystal

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

Ilyn, Max; Magana, Ana; Walter, Andrew Leigh

Here, vicinal surfaces may undergo structural transformations as a function of temperature or in the presence of adsorbates. Step-doubling, in which monatomic steps pair up forming double-atom high staircases, is the simplest example. Here we investigate the case of Ni(111) using a curved crystal surface, which allows us to explore the occurrence of step-doubling as a function of temperature and vicinal plane (miscut α and step type). We find a striking A-type ({100}-like microfacets) versus B-type ({111}-like) asymmetry towards step-doubling. The terrace-width distribution analysis performed from Scanning Tunneling Microscopy data points to elastic step interactions overcoming entropic effects at verymore » small miscut α in A-type vicinals, as compared to B-type steps. For A-type vicinals, we elaborate the temperature/miscut phase diagram, on which we establish a critical miscut α c = 9.3° for step-doubling to take place.« less

Quantification and characterisation of fatty acid methyl esters in microalgae: Comparison of pretreatment and purification methods.

PubMed

Lage, Sandra; Gentili, Francesco G

2018-06-01

A systematic qualitative and quantitative analysis of fatty acid methyl esters (FAMEs) is crucial for microalgae species selection for biodiesel production. The aim of this study is to identify the best method to assess microalgae FAMEs composition and content. A single-step method, was tested with and without purification steps-that is, separation of lipid classes by thin-layer chromatography (TLC) or solid-phase extraction (SPE). The efficiency of a direct transesterification method was also evaluated. Additionally, the yield of the FAMEs and the profiles of the microalgae samples with different pretreatments (boiled in isopropanol, freezing, oven-dried and freeze-dried) were compared. The application of a purification step after lipid extraction proved to be essential for an accurate FAMEs characterisation. The purification methods, which included TLC and SPE, provided superior results compared to not purifying the samples. Freeze-dried microalgae produced the lowest FAMEs yield. However, FAMEs profiles were generally equivalent among the pretreatments. Copyright © 2018 Elsevier Ltd. All rights reserved.

Unusual catalysts from molasses: synthesis, properties and application in obtaining biofuels from algae.

PubMed

Samorì, Chiara; Torri, Cristian; Fabbri, Daniele; Falini, Giuseppe; Faraloni, Cecilia; Galletti, Paola; Spera, Silvia; Tagliavini, Emilio; Torzillo, Giuseppe

2012-08-01

Acid catalysts were prepared by sulfonation of carbon materials obtained from the pyrolysis of sugar beet molasses, a cheap, viscous byproduct in the processing of sugar beets into sugar. Conditions for the pyrolysis of molasses (temperature and time) influenced catalyst performance; the best combination came from pyrolysis at low temperature (420 °C) for a relatively long time (8-15 h), which ensured better stability of the final material. The most effective molasses catalyst was highly active in the esterification of fatty acids with methanol (100 % yield after 3 h) and more active than common solid acidic catalysts in the transesterification of vegetable oils with 25-75 wt % of acid content (55-96 % yield after 8 h). A tandem process using a solid acid molasses catalyst and potassium hydroxide in methanol was developed to de-acidificate and transesterificate algal oils from Chlamydomonas reinhardtii, Nannochloropsis gaditana, and Phaeodactylum tricornutum, which contain high amounts of free fatty acids. The amount of catalyst required for the de-acidification step was influenced by the chemical composition of the algal oil, thus operational conditions were determined not only in relation to free fatty acids content in the oil, but according to the composition of the lipid extract of each algal species. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

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.

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.

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.

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.

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.

Production of biodiesel by transesterification of corn and soybean oils with ethanol or butanol using resin-bound truncated Candida antarctica lipase B

USDA-ARS?s Scientific Manuscript database

Enzymatic catalysts, such as lipases, have advantages over chemical catalysts for transesterification of triglycerides to produce biodiesel. A gene encoding a synthetic truncated Candida antarctica lipase B (CALB) was generated via automated PCR and expressed in Saccharomyces cerevisiae. Western b...

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.

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.

Biodiesel production with continuous supercritical process: non-catalytic transesterification and esterification with or without carbon dioxide.

PubMed

Tsai, Yu-Ting; Lin, Ho-mu; Lee, Ming-Jer

2013-10-01

The non-catalytic transesterification of refined sunflower oil with supercritical methanol, in the presence of carbon dioxide, was conducted in a tubular reactor at temperatures from 553.2 to 593.2K and pressures up to 25.0 MPa. The FAME yield can be achieved up to about 0.70 at 593.2 K and 10.0 MPa in 23 min with methanol:oil of 25:1 in molar ratio. The effect of adding CO2 on the FAME yield is insignificant. The kinetic behavior of the non-catalytic esterification and transesterification of oleic acid or waste cooking oil (WCO) with supercritical methanol was also investigated. By using the supercritical process, the presence of free fatty acid (FFA) in WCO gives positive contribution to FAME production. The FAME yield of 0.90 from WCO can be achieved in 13 min at 573.2K. The kinetic data of supercritical transesterification and esterifaication were correlated well with a power-law model. Copyright © 2012 Elsevier Ltd. All rights reserved.

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.

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.

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.

RNA splicing process analysis for identifying antisense oligonucleotide inhibitors with padlock probe-based isothermal amplification† †Electronic supplementary information (ESI) available: Additional experimental materials, methods, DNA sequences and supplementary figures and tables. See DOI: 10.1039/c7sc01336a Click here for additional data file.

PubMed Central

Ren, Xiaojun; Deng, Ruijie; Wang, Lida; Zhang, Kaixiang

2017-01-01

RNA splicing, which mainly involves two transesterification steps, is a fundamental process of gene expression and its abnormal regulation contributes to serious genetic diseases. Antisense oligonucleotides (ASOs) are genetic control tools that can be used to specifically control genes through alteration of the RNA splicing pathway. Despite intensive research, how ASOs or various other factors influence the multiple processes of RNA splicing still remains obscure. This is largely due to an inability to analyze the splicing efficiency of each step in the RNA splicing process with high sensitivity. We addressed this limitation by introducing a padlock probe-based isothermal amplification assay to achieve quantification of the specific products in different splicing steps. With this amplified assay, the roles that ASOs play in RNA splicing inhibition in the first and second steps could be distinguished. We identified that 5′-ASO could block RNA splicing by inhibiting the first step, while 3′-ASO could block RNA splicing by inhibiting the second step. This method provides a versatile tool for assisting efficient ASO design and discovering new splicing modulators and therapeutic drugs. PMID:28989608

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.

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...

Mixed alkyl esters from cottonseed oil: Improved biodiesel properties and blends with ultra-low sulfur diesel fuel

USDA-ARS?s Scientific Manuscript database

Transesterification of refined cottonseed oil was carried out with methanol, ethanol, 1-butanol, and various mixtures of these alcohols at constant volume ratio of alcohol to oil (1:2) using KOH (1 wt%) as catalyst to produce biodiesel. In the mixed alcohol transesterifications, the formation of met...

Single-step transesterification with simultaneous concentration and stable isotope analysis of fatty acid methyl esters by gas chromatography-combustion-isotope ratio mass spectrometry.

PubMed

Panetta, Robert J; Jahren, A Hope

2011-05-30

Gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) is increasingly applied to food and metabolic studies for stable isotope analysis (δ(13) C), with the quantification of analyte concentration often obtained via a second alternative method. We describe a rapid direct transesterification of triacylglycerides (TAGs) for fatty acid methyl ester (FAME) analysis by GC-C-IRMS demonstrating robust simultaneous quantification of amount of analyte (mean r(2) =0.99, accuracy ±2% for 37 FAMEs) and δ(13) C (±0.13‰) in a single analytical run. The maximum FAME yield and optimal δ(13) C values are obtained by derivatizing with 10% (v/v) acetyl chloride in methanol for 1 h, while lower levels of acetyl chloride and shorter reaction times skewed the δ(13) C values by as much as 0.80‰. A Bland-Altman evaluation of the GC-C-IRMS measurements resulted in excellent agreement for pure oils (±0.08‰) and oils extracted from French fries (±0.49‰), demonstrating reliable simultaneous quantification of FAME concentration and δ(13) C values. Thus, we conclude that for studies requiring both the quantification of analyte and δ(13) C data, such as authentication or metabolic flux studies, GC-C-IRMS can be used as the sole analytical method. Copyright © 2011 John Wiley & Sons, Ltd.

Determination of Total Lipids as Fatty Acid Methyl Esters (FAME) by in situ Transesterification: Laboratory Analytical Procedure (LAP)

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

Van Wychen, Stefanie; Ramirez, Kelsey; Laurens, Lieve M. L.

2016-01-13

This procedure is based on a whole biomass transesterification of lipids to fatty acid methyl esters to represent an accurate reflection of the potential of microalgal biofuels. Lipids are present in many forms and play various roles within an algal cell, from cell membrane phospholipids to energy stored as triacylglycerols.

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.

A simplified and efficient method for the analysis of fatty acid methyl esters suitable for large clinical studies.

PubMed

Masood, Athar; Stark, Ken D; Salem, Norman

2005-10-01

Conventional sample preparation for fatty acid analysis is a complicated, multiple-step process, and gas chromatography (GC) analysis alone can require >1 h per sample to resolve fatty acid methyl esters (FAMEs). Fast GC analysis was adapted to human plasma FAME analysis using a modified polyethylene glycol column with smaller internal diameters, thinner stationary phase films, increased carrier gas linear velocity, and faster temperature ramping. Our results indicated that fast GC analyses were comparable to conventional GC in peak resolution. A conventional transesterification method based on Lepage and Roy was simplified to a one-step method with the elimination of the neutralization and centrifugation steps. A robotics-amenable method was also developed, with lower methylation temperatures and in an open-tube format using multiple reagent additions. The simplified methods produced results that were quantitatively similar and with similar coefficients of variation as compared with the original Lepage and Roy method. The present streamlined methodology is suitable for the direct fatty acid analysis of human plasma, is appropriate for research studies, and will facilitate large clinical trials and make possible population studies.

Biodiesel from dewatered wastewater sludge: a two-step process for a more advantageous production.

PubMed

Pastore, Carlo; Lopez, Antonio; Lotito, Vincenzo; Mascolo, Giuseppe

2013-07-01

Alternative approaches for obtaining biodiesel from municipal sludge have been successfully investigated. In order to avoid the expensive conventional preliminary step of sludge drying, dewatered sludge (TSS: 15wt%) was used as starting material. The best performance in terms of yield of fatty acid methyl esters (18wt%) with the lowest energy demand (17MJkgFAME(-1)) was obtained by a new two-step approach based on hexane extraction carried out directly on dewatered acidified (H2SO4) sludge followed by methanolysis of extracted lipids. It was found that sulphuric acid plays a key role in the whole process not only for the transesterification of glycerides but also for the production of new free fatty acids from soaps and their esterification with methanol. In addition to biodiesel production, the investigated process allows valorization of primary sludge as it turns it into a valuable source of chemicals, namely sterols (2.5wt%), aliphatic alcohols (0.8wt%) and waxes (2.3wt%). Copyright © 2013 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.

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.

Base catalytic transesterification of vegetable oil.

PubMed

Mainali, Kalidas

2012-01-01

Sustainable economic and industrial growth requires safe, sustainable resources of energy. Biofuel is becoming increasingly important as an alternative fuel for the diesel engine. The use of non-edible vegetable oils for biofuel production is significant because of the increasing demand for edible oils as food. With the recent debate of food versus fuel, some non-edible oils like soapnut and Jatropha (Jatropha curcus. L) are being investigated as possible sources of biofuel. Recent research has focused on the application of heterogeneous catalysis. This review considers catalytic transesterification and the possibility of heterogeneous base catalysts. The process of transesterification, and the effect of parameters, mechanism and kinetics are reviewed. Although chromatography (GC and HPLC) are the analytical methods most often used for biofuel characterization, other techniques and some improvements to analytical methods are discussed.

Microwave assisted alkali-catalyzed transesterification of Pongamia pinnata seed oil for biodiesel production.

PubMed

Kumar, Ritesh; Kumar, G Ravi; Chandrashekar, N

2011-06-01

In this study, microwave assisted transesterification of Pongamia pinnata seed oil was carried out for the production of biodiesel. The experiments were carried out using methanol and two alkali catalysts i.e., sodium hydroxide (NaOH) and potassium hydroxide (KOH). The experiments were carried out at 6:1 alcohol/oil molar ratio and 60°C reaction temperature. The effect of catalyst concentration and reaction time on the yield and quality of biodiesel was studied. The result of the study suggested that 0.5% sodium hydroxide and 1.0% potassium hydroxide catalyst concentration were optimum for biodiesel production from P. pinnata oil under microwave heating. There was a significant reduction in reaction time for microwave induced transesterification as compared to conventional heating. Copyright © 2011 Elsevier Ltd. All rights reserved.

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.

Inductance Calculations of Variable Pitch Helical Inductors

DTIC Science & Technology

2015-08-01

8217 ’ Integral solution using Simpson’s Rule ’ Dim i As Integer Dim Pi As Double, uo As Double, kc As Double Dim a As Double, amax As Double, da As...Double Dim steps As Integer Dim func1a As Double, func1b As Double ’ On Error GoTo err_TorisV1 steps = 1000 Pi = 3.14159 uo = 4 * Pi * 0.0000001...As Double ’ ’ Integral solution using Simpson’s Rule ’ Dim i As Integer Dim Pi As Double, uo As Double, kc As Double Dim a As Double, amax As

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.

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.

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.

Morphological Study on Porous Silicon Carbide Membrane Fabricated by Double-Step Electrochemical Etching

NASA Astrophysics Data System (ADS)

Omiya, Takuma; Tanaka, Akira; Shimomura, Masaru

2012-07-01

The structure of porous silicon carbide membranes that peeled off spontaneously during electrochemical etching was studied. They were fabricated from n-type 6H SiC(0001) wafers by a double-step electrochemical etching process in a hydrofluoric electrolyte. Nanoporous membranes were obtained after double-step etching with current densities of 10-20 and 60-100 mA/cm2 in the first and second steps, respectively. Microporous membranes were also fabricated after double-step etching with current densities of 100 and 200 mA/cm2. It was found that the pore diameter is influenced by the etching current in step 1, and that a higher current is required in step 2 when the current in step 1 is increased. During the etching processes in steps 1 and 2, vertical nanopore and lateral crack formations proceed, respectively. The influx pathway of hydrofluoric solution, expansion of generated gases, and transfer limitation of positive holes to the pore surface are the key factors in the peeling-off mechanism of the membrane.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Conversion and recovery of saponifiable lipids from microalgae using a nonpolar solvent via lipase-assisted extraction.

PubMed

Law, Sam Q K; Halim, Ronald; Scales, Peter J; Martin, Gregory J O

2018-07-01

A single-step method for transesterifying and recovering lipids in concentrated slurries (ca 20% w/w solids) of ruptured microalgae is presented. A soluble Rhizomucor miehei lipase (RML) was used to directly transesterify the lipids in the marine microalgae Nannochloropsis salina. This allowed both triglycerides (TAG) and polar saponifiable lipids to be recovered as fatty acid methyl esters (FAME) using a nonpolar solvent (hexane). Up to 90 wt% of the total saponifiable lipids (SL) were converted to FAME within 24 h, approximately 75% of which was recovered in the hexane by centrifugation. Two pathways for the conversion and recovery of polar lipids were identified. The water in the slurry buffered against potential lipase inhibition by methanol, but necessitated a high methanol dose for maximal FAME conversion. Nonetheless the method enables the recovery of polar lipids as FAME while avoiding the need for both drying of the biomass and a downstream transesterification step. Copyright © 2018 Elsevier Ltd. All rights reserved.

Transesterification of rapeseed oil for biodiesel production in trickle-bed reactors packed with heterogeneous Ca/Al composite oxide-based alkaline catalyst.

PubMed

Meng, Yong-Lu; Tian, Song-Jiang; Li, Shu-Fen; Wang, Bo-Yang; Zhang, Min-Hua

2013-05-01

A conventional trickle bed reactor and its modified type both packed with Ca/Al composite oxide-based alkaline catalysts were studied for biodiesel production by transesterification of rapeseed oil and methanol. The effects of the methanol usage and oil flow rate on the FAME yield were investigated under the normal pressure and methanol boiling state. The oil flow rate had a significant effect on the FAME yield for the both reactors. The modified trickle bed reactor kept over 94.5% FAME yield under 0.6 mL/min oil flow rate and 91 mL catalyst bed volume, showing a much higher conversion and operational stability than the conventional type. With the modified trickle bed reactor, both transesterification and methanol separation could be performed simultaneously, and glycerin and methyl esters were separated additionally by gravity separation. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

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.

Biodiesel Production from Citrillus colocynthis Oil Using Enzymatic Based Catalytic Reaction and Characterization Studies.

PubMed

Nehdi, Imededdine Arbi; Sbihi, Hassen Mohamed; Blidi, Lahssen El; Rashid, Umer; Tan, Chin Ping; Al-Resayes, Saud Ibrahim

2018-01-01

Biodiesel is a green fuel consisting of long chain fatty acid monoalkyl esters, which can be blended with diesel or used alone which is usually produced from vegetable oils/fats by either lipasecatalyzed transesterification. In this investigation, an enzyme (Novozym 435) catalyzed process was optimized to prepare methyl esters from crude Citrullus colocynthis oil (CCO) by transesterification of CCO with methanol. However, as per our knowledge, lipase-catalyzed transesterification have not been used for biodiesel production from Citrullus colocynthis. The purpose of this work was to transesterify the CCO in the presence of Candida antarctica lipase as catalyst and methanol. Additionally, the physicochemical parameters/fuel properties of the Citrullus colocynthis methyl ester (CCME) were assessed and compared. Lipase-catalyzed reactions were carried out in three necked flask (50 mL) attached with reflux condenser and thermometer, immersed in oil bath at constant stirring speed (400 rpm). The reaction mixture was consisted of CCO and varying the calculated amount of methanol, tert-butyl alcohol, and Novozym 435. The experimental parameters reaction time, methanol/oil molar ratio, reaction temperature, tert-butanol content, Novozym 435 content and water content were optimized for the transesterification reaction. The CCME yield was measured using gas chromatograph. The fuel properties of the produced CCME were determined as per American Society for Testing and Materials (ASTM) and European (EN) biodiesel standard methods. In this study, an enzymatic catalyst was employed to synthesize the CCME from CCO via transesterification. Several variables affecting the CCME yield were optimized as lipase quantity (4%), water content (0.5%), methanol/oil molar ratio (5:1), reaction temperature (43 °C), reaction medium composition (80% tertbutanol/ oil), and reaction time (3.7 h). A CCME yield of 97.8% was achieved using enzyme catalyzed transesterification of CCO under optimal conditions. The significant biodiesel fuel properties of CCME, i.e. cloud point (0.70 °C); cetane number (49.07); kinematic viscosity (2.27 mm2/s); flash point (143 °C); sulfur content (2 ppm) density (880 kg/m3) and acid value (0.076 mg KOH/g) were appraised. CCME also exhibited long-term storage stability (4.80 h) and all the biodiesel fuel properties were within the range of standards (ASTM D6751 and EN 14214). The lipase-catalyzed transesterification produced better conversion than the base-catalyzed reaction. The fuel properties of CCME were within the limits of the ASTM D6751 and EN14214 standards. Furthermore, CCME showed good oxidative stability and a long shelf life due its high natural antioxidant content. CCME showed better fuel properties and long-term storage stability due to which it can be used as a potential alternative fuel. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Efficient green methanol synthesis from glycerol

NASA Astrophysics Data System (ADS)

Haider, Muhammad H.; Dummer, Nicholas F.; Knight, David W.; Jenkins, Robert L.; Howard, Mark; Moulijn, Jacob; Taylor, Stuart H.; Hutchings, Graham J.

2015-12-01

The production of biodiesel from the transesterification of plant-derived triglycerides with methanol has been commercialized extensively. Impure glycerol is obtained as a by-product at roughly one-tenth the mass of the biodiesel. Utilization of this crude glycerol is important in improving the viability of the overall process. Here we show that crude glycerol can be reacted with water over very simple basic or redox oxide catalysts to produce methanol in high yields, together with other useful chemicals, in a one-step low-pressure process. Our discovery opens up the possibility of recycling the crude glycerol produced during biodiesel manufacture. Furthermore, we show that molecules containing at least two hydroxyl groups can be converted into methanol, which demonstrates some aspects of the generality of this new chemistry.

Synergetic effect of double-step blocking layer for the perovskite solar cell

NASA Astrophysics Data System (ADS)

Kim, Jinhyun; Hwang, Taehyun; Lee, Sangheon; Lee, Byungho; Kim, Jaewon; Kim, Jaewook; Gil, Bumjin; Park, Byungwoo

2017-10-01

In an organometallic CH3NH3PbI3 (MAPbI3) perovskite solar cell, we have demonstrated a vastly compact TiO2 layer synthesized by double-step deposition, through a combination of sputter and solution deposition to minimize the electron-hole recombination and boost the power conversion efficiency. As a result, the double-step strategy allowed outstanding transmittance of blocking layer. Additionally, crystallinity and morphology of the perovskite film were significantly modified, provoking enhanced photon absorption and solar cell performance with the reduced recombination rate. Thereby, this straightforward double-step strategy for the blocking layer exhibited 12.31% conversion efficiency through morphological improvements of each layer.

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.

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.

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.

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.

Corrosion-Related Consequences of Biodiesel in Contact with Natural Seawater

DTIC Science & Technology

2010-03-01

petroleum diesel, biodiesel contains no sulfur. In the U.S. the term “biodiesel” is standardized as fatty acid methyl ester ( FAME ). Biodiesel content is...Form 298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 to methyl (or ethyl) esters with a process known as transesterification.4 The transesterification...biodegradation of the vegetable methyl esters in agitated San Francisco Bay water was less than 4 days at 17 °C.4,22 The highest corrosion rates

Heterogeneous catalysis for sustainable biodiesel production via esterification and transesterification.

PubMed

Lee, Adam F; Bennett, James A; Manayil, Jinesh C; Wilson, Karen

2014-11-21

Concern over the economics of accessing fossil fuel reserves, and widespread acceptance of the anthropogenic origin of rising CO2 emissions and associated climate change from combusting such carbon sources, is driving academic and commercial research into new routes to sustainable fuels to meet the demands of a rapidly rising global population. Here we discuss catalytic esterification and transesterification solutions to the clean synthesis of biodiesel, the most readily implemented and low cost, alternative source of transportation fuels to meet future societal demands.

Atomic Resolution in Situ Imaging of a Double-Bilayer Multistep Growth Mode in Gallium Nitride Nanowires

DOE PAGES

Gamalski, A. D.; Tersoff, J.; Stach, E. A.

2016-04-13

We study the growth of GaN nanowires from liquid Au–Ga catalysts using environmental transmission electron microscopy. GaN wires grow in either (11¯20) or (11¯00) directions, by the addition of {11¯00} double bilayers via step flow with multiple steps. Step-train growth is not typically seen with liquid catalysts, and we suggest that it results from low step mobility related to the unusual double-height step structure. Finally, the results here illustrate the surprising dynamics of catalytic GaN wire growth at the nanoscale and highlight striking differences between the growth of GaN and other III–V semiconductor nanowires.

Ultrasound-assisted in-situ transesterification of wet Aurantiochytrium sp. KRS 101 using potassium carbonate.

PubMed

Sung, Mina; Han, Jong-In

2018-08-01

A new in-situ transesterification method was developed for wet biomass: K 2 CO 3 was used as an alkaline catalyst and, Aurantiochytrium sp. KRS 101 as oleaginous DHA-producing microalgae. It was found that the presence of water greatly impaired the overall efficiency even with the powerful catalyst that had worked surpassingly well with dry biomass, and thus a mechanical aid like ultrasonication was needed to make advantage of full potential of the alkaline catalyst. The total fatty acid ethyl ester (FAEE) recovery yield of 94.6% was achieved with sonication at 100 g/L of biomass (40% moisture), 3% of K 2 CO 3 , 70 °C and 30 min. All these suggest that the ultrasound assisted in-situ transesterification can offer a feasible means for FAEE recovery and it was so by way of overcoming the physical limitation of mass transfer caused the presence of water and providing effective contacts between reactants. Copyright © 2018. Published by Elsevier Ltd.

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.

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.

(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.

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.

Efficient production of biodiesel from waste grease: one-pot esterification and transesterification with tandem lipases.

PubMed

Yan, Jinyong; Li, Aitao; Xu, Yi; Ngo, Thao P N; Phua, Szechao; Li, Zhi

2012-11-01

A novel concept and efficient method for producing biodiesel (FAME) from grease (15-40wt% free fatty acid, FFA) were developed by using tandem lipases for one-pot esterification of FFA and transesterification of triglyceride with methanol in a solvent-free system. Combining immobilized Candida antarctica lipase B (CALB) (Novozyme 435) favoring the esterification and immobilized Thermomyces lanuginosus lipase (TLL) (Lipozyme TLIM) preferring the transesterification at 2:8 (wt/wt) gave FAME in 80% yield, being better than that with Novozyme 435 or Lipozyme TLIM. Recombinant Escherichia coli (Calb/Tll) co-expressing CALB and TLL was engineered as a more efficient tandem-lipases system. Using wet or dry cells (4wt%) gave FAME in 87% or 95% yield, which is much better than that with E. coli cells expressing either CALB or TLL alone. Cells of E. coli (Calb/Tll) were recycled for five times and retained 75% productivity, thus being practical for producing biodiesel from grease. Copyright © 2012 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.

One-pot process combining transesterification and selective hydrogenation for biodiesel production from starting material of high degree of unsaturation.

PubMed

Yang, Ru; Su, Mengxing; Li, Min; Zhang, Jianchun; Hao, Xinmin; Zhang, Hua

2010-08-01

A one-pot process combining transesterification and selective hydrogenation was established to produce biodiesel from hemp (Cannabis sativa L.) seed oil which is eliminated as a potential feedstock by a specification of iodine value (IV; 120 g I(2)/100g maximum) contained in EN 14214. A series of alkaline earth metal oxides and alkaline earth metal supported copper oxide were prepared and tested as catalysts. SrO supported 10 wt.% CuO showed the superior catalytic activity for transesterification with a biodiesel yield of 96% and hydrogenation with a reduced iodine value of 113 and also exhibited a promising selectivity for eliminating methyl linolenate and increasing methyl oleate without rising methyl stearate in the selective hydrogenation. The fuel properties of the selective hydrogenated methyl esters are within biodiesel specifications. Furthermore, cetane numbers and iodine values were well correlated with the compositions of the hydrogenated methyl esters according to degrees of unsaturation. (c) 2010 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.

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

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.

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.

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.

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

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.

Application of a 1,1,3,3-tetramethylguanidine (TMG)/MeOH-CO2 in situ derivatization procedure for the gas chromatographic characterization of the fatty acid profile in olive oil.

PubMed

Saliu, F; Anzano, M; Franzetti, A

2015-03-01

1,1,3,3-Tetramethylguanidine (TMG), methanol and carbon dioxide were investigated as switchable polarity solvents (SPS) in the simultaneous derivatization and extraction of triacylglycerols for the gas chromatographic (GC) characterization of olive oil. Three commercial olive oils were used as test samples. Results of the developed method did not differ statistically from those provided by reference derivatization procedures. The transesterification reaction was carried out under a very mild condition, one step and in situ, and no particular matrix interferences were evidenced. The method represented the first example of the use of a switchable polarity mixture for the preparation of methyl ester derivatives of fatty acids (FAME).

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.

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.

Designed Single-Step Synthesis, Structure, and Derivative Textural Properties of Well-Ordered Layered Penta-Coordinate Silicon Alcoholate Complexes

PubMed Central

Li, Xiansen; Michaelis, Vladimir K.; Ong, Ta-Chung; Smith, Stacey J.; Griffin, Robert G.; Wang, Evelyn N.

2014-01-01

The controllable synthesis of well-ordered layered materials with specific nanoarchitecture poses a grand challenge in materials chemistry. We report the solvothermal synthesis of two structurally analogous 5-coordinate organosilicate complexes via a novel transesterification mechanism. Since the polycrystalline nature of the intrinsic hypervalent Si complex thwarts the endeavor in determining its structure, a novel strategy concerning the elegant addition of a small fraction of B species as an effective crystal growth mediator and a sacrificial agent is proposed to directly prepare diffraction-quality single crystals without disrupting the intrinsic elemental type. In the determined crystal structure, two monomeric primary building units (PBUs) self-assemble into a dimeric asymmetric secondary BU via strong Na+-O2− ionic bonds. The designed one-pot synthesis is straightforward, robust, and efficient, leading to a well-ordered (10ī)-parallel layered Si complex with its principal interlayers intercalated with extensive van der Waals gaps in spite of the presence of substantial Na+ counterions as a result of unique atomic arrangement in its structure. On the other hand, upon fast pyrolysis, followed by acid leaching, both complexes are converted into two SiO2 composites bearing BET surface areas of 163.3 and 254.7 m2 g−1 for the pyrolyzed intrinsic and B-assisted Si complexes, respectively. The transesterification methodology merely involving alcoholysis but without any hydrolysis side reaction is designed to have generalized applicability for use in synthesizing new layered metal-organic compounds with tailored PBUs and corresponding metal oxide particles with hierarchical porosity. PMID:24737615

Effect of double-layer application on bond quality of adhesive systems.

PubMed

Fujiwara, Satoshi; Takamizawa, Toshiki; Barkmeier, Wayne W; Tsujimoto, Akimasa; Imai, Arisa; Watanabe, Hidehiko; Erickson, Robert L; Latta, Mark A; Nakatsuka, Toshiyuki; Miyazaki, Masashi

2018-01-01

The aim of this study was to determine the effect of double-layer application of universal adhesives on the bond quality and compare to other adhesive systems. Two universal adhesives used were in this study: Scotchbond Universal (SU), [3M ESPE] and Prime & Bond elect (PE), [Dentsply Caulk]. The conventional single-step self-etch adhesives G-ӕnial Bond (GB), [GC Corporation.] and BeautiBond (BB), [Shofu Inc.], and a two-step self-etch adhesive, Optibond XTR (OX), [Kerr Corporation], were used as comparison adhesives. Shear bond strengths (SBS) and shear fatigue strengths (SFS) to human enamel and dentin were measured in single application mode and double application mode. For each test condition, 15 specimens were prepared for SBS testing and 30 specimens for SFS testing. Enamel and dentin SBS of the universal adhesives in the double application mode were significantly higher than those of the single application mode. In addition, the universal adhesives in the double application mode had significantly higher dentin SFS values than those of the single application mode. The two-step self-etch adhesive OX tended to have lower bond strengths in the double application mode, regardless of the test method or adherent substrate. The double application mode is effective in enhancing SBS and SFS of universal adhesives, but not conventional two-step self-etch adhesives. These results suggest that, although the double application mode may enhance the bonding quality of a universal adhesive, it may be counter-productive for two-step self-etch adhesives in clinical use. Copyright © 2017 Elsevier Ltd. All rights reserved.

Theoretical aspects of methyl acetate and methanol activation on MgO(100) and (501) catalyst surfaces with application in FAME production

NASA Astrophysics Data System (ADS)

Man, Isabela-Costinela; Soriga, Stefan Gabriel; Parvulescu, Vasile

2017-01-01

Density functional theory (DFT) calculations were carried out to study the activation of methyl acetate and methanol on MgO(100) and MgO(501) surfaces and integrated in the context of transesterification, interesterification and glycerolysis reactions used in biodiesel industry. First results indicate the importance of including of dispersion forces in the calculations. On MgO(100) the reverse reactions steps of Csbnd O and Csbnd H dissociations and on MgO(501) the same reverse reaction step of Csbnd H dissociations of methyl acetate are energetically favorable, while the dissociation of Csbnd O bond into methoxide and acetate fragments on the edge of MgO(501) was found to be exothermic with a low activation energy. For methanol, the dissociation of Osbnd H bond on MgO(100) surface in the presence of the second coadsorbed methanol molecule becomes more energetically favoured compared to the isolated molecule, due to the fact that the methoxide fragment is stabilized by intermolecular hydrogen bonding. This is reflected by the decrease of the activation energy of the forward reaction step and the increase of the activation energy of the backward reaction step, increasing the probability to have dissociated molecules among the undissociated ones. These results represent a step forward for better understanding from atomistic point of view the paths of these reactions on these surfaces for the corresponding catalytic processes.

Diesel Fuel from Used Frying Oil

PubMed Central

Buczek, Bronislaw

2014-01-01

New conversion technologies of used edible oils and waste animal fats into a biofuel appropriate for use in standard diesel engines have been developed, taking into consideration environmental requirements and improvement in the economics of current trans-esterification technologies. The variation in the properties of substrates made from used rape oil after treatment with mixed adsorbents (active carbon, magnesium silicate) was studied in this work. The obtained results are compared with the quality requirements for the substrates used in Vogel & Noot GmbH technology for transesterification of oils and fats. PMID:24574908

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.

The Design and its Verification of the Double Rotor Double Cage Induction Motor

NASA Astrophysics Data System (ADS)

Sinha, Sumita; Deb, Nirmal K.; Biswas, Sujit K.

2017-02-01

The concept of a double rotor motor presented earlier and its equivalent circuit has been developed, showing a non-linear parameter content. The two rotors (which are recommended to be double cage type for development of high starting torque) can run with equal or unequal speed independently, depending on their individual loading. This paper presents the elaborate design procedure, step-by-step, for the double rotor double cage motor and verifies the designed data with that obtained from three separate tests (compared to two for conventional motor) on a prototype, such that optimum performance can be obtained from the motor.

Effect of supercritical carbon dioxide on the enzymatic production of biodiesel from waste animal fat using immobilized Candida antarctica lipase B variant.

PubMed

Pollardo, Aldricho Alpha; Lee, Hong-Shik; Lee, Dohoon; Kim, Sangyong; Kim, Jaehoon

2017-09-09

Waste animal fat is a promising feedstock to replace vegetable oil that widely used in commercial biodiesel process, however the high content of free fatty acid in waste fat makes it unfeasible to be processed with commercial base-catalytic process. Enzymatic process is preferable to convert waste fat into biodiesel since enzyme can catalyze both esterification of free fatty acid and transesterification of triglyceride. However, enzymatic reaction still has some drawbacks such as lower reaction rates than base-catalyzed transesterification and the limitation of reactant concentration due to the enzyme inhibition of methanol. Supercritical CO 2 is a promising reaction media for enzyme-catalyzed transesterification to overcome those drawbacks. The transesterification of waste animal fat was carried out in supercritical CO 2 with varied concentration of feedstock and methanol in CO 2 . The CO 2 to feedstock mass ratio of 10:1 showed the highest yield compared to other ratios, and the highest FAME yield obtained from waste animal fat was 78%. The methanol concentration effect was also observed with variation 12%, 14%, and 16% of methanol to feedstock ratio. The best yield was 87% obtained at the CO 2 to feedstock ratio of 10: 1 and at the methanol to feedstock ratio of 14% after 6 h of reaction. Enzymatic transesterification to produce biodiesel from waste animal fat in supercritical fluid media is a potential method for commercialization since it could enhance enzyme activity due to supercritical fluid properties to remove mass transfer limitation. The high yield of FAME when using high mass ratio of CO 2 to oil showed that supercritical CO 2 could increase the reaction and mass transfer rate while reducing methanol toxicity to enzyme activity. The increase of methanol concentration also increased the FAME yield because it might shift the reaction equilibrium to FAME production. This finding describes that the application of supercritical CO 2 in the enzymatic reaction enables the application of simple process such as a packed-bed reactor.

Double emulsion formation through hierarchical flow-focusing microchannel

NASA Astrophysics Data System (ADS)

Azarmanesh, Milad; Farhadi, Mousa; Azizian, Pooya

2016-03-01

A microfluidic device is presented for creating double emulsions, controlling their sizes and also manipulating encapsulation processes. As a result of three immiscible liquids' interaction using dripping instability, double emulsions can be produced elegantly. Effects of dimensionless numbers are investigated which are Weber number of the inner phase (Wein), Capillary number of the inner droplet (Cain), and Capillary number of the outer droplet (Caout). They affect the formation process, inner and outer droplet size, and separation frequency. Direct numerical simulation of governing equations was done using volume of fluid method and adaptive mesh refinement technique. Two kinds of double emulsion formation, the two-step and the one-step, were simulated in which the thickness of the sheath of double emulsions can be adjusted. Altering each dimensionless number will change detachment location, outer droplet size and droplet formation period. Moreover, the decussate regime of the double-emulsion/empty-droplet is observed in low Wein. This phenomenon can be obtained by adjusting the Wein in which the maximum size of the sheath is discovered. Also, the results show that Cain has significant influence on the outer droplet size in the two-step process, while Caout affects the sheath in the one-step formation considerably.

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

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.

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.

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.

Voluntary saccadic eye movements in humans studied with a double-cue paradigm.

PubMed

Sheliga, B M; Brown, V J; Miles, F A

2002-07-01

In the classic double-step paradigm, subjects are required to make a saccade to a visual target that is briefly presented at one location and then shifted to a new location before the subject has responded. The saccades in this situation are "reflexive" in that they are made in response to the appearance of the target itself. In the present experiments we adapted the double-step paradigm to study "voluntary" saccades. For this, several identical targets were always visible and subjects were given a cue to indicate that they should make a saccade to one of them. This cue was then changed to indicate another of the targets before the subject had responded: double-cue (DC) paradigm. The saccadic eye movements in our DC paradigm had many features in common with those in the double-step paradigm and we show that apparent differences can be attributed to the spatio-temporal arrangements of the cues/targets rather than to any intrinsic differences in the programming of these two kinds of eye movements. For example, a feature of our DC paradigm that is not seen in the usual double-step paradigm is that the second cue could cause transient delays of the initial saccade, and these delays still occurred when the second cue was reflexive--provided that it was at the fovea (as in our DC paradigm) and not in the periphery (as in the usual double-step paradigm). Thus, the critical factor for the delay was the retinal (foveal) location of the second cue/target--not whether it was cognitive or reflexive--and we argue that the second cue/target is here acting as a distractor. We conclude that the DC paradigm can be used to study the programming of voluntary saccades in the same way that the double-step paradigm can be used to study reflexive saccades.

Determination of physiochemical properties of palm oil methyl ester catalyzed by waste cockle shells

NASA Astrophysics Data System (ADS)

Nasir, Nurul Fitriah; Latif, Noradila Abdul; Bakar, Sharifah Adzila Syed Abu; Rahman, Mohd Nasrull Abdul; Selamat, Siti Norhidayah; Nasharudin, Nurul Nadirah

2017-04-01

Waste cockle shell can be used as a source of calcium oxide (CaO) in catalyzing a transesterification reaction to produce biodiesel or fatty acid methyl ester (FAME). This aim of this paper is to determine the physicochemical properties of (FAME) which utilize waste cockle shells in the transesterification reaction process. In this study, the catalyst was prepared using high temperature furnace (700°C) for 4 h. The molar ratio of methanol to oil was fixed at 9:1 and the reaction temperature and catalyst concentration were varied from 65 -70 °C, and 10-30 wt. %, respectively for transesterification reaction. The reaction time was also fixed at 3 h. The analyzed physicochemical properties were density, viscosity, flash point and net heat of combustion. The results obtained from the analysis found that reaction temperature 65°C with 30% of catalyst concentration has produced the physical properties of FAME that comply the biodiesel standards. The results suggest that reaction temperature and catalyst concentration have influence on the value of physicochemical properties of FAME produced.

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.

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.

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.

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.

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.

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.

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.

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.

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 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.

Paediatric nurses' adherence to the double-checking process during medication administration in a children's hospital: an observational study.

PubMed

Alsulami, Zayed; Choonara, Imti; Conroy, Sharon

2014-06-01

To evaluate how closely double-checking policies are followed by nurses in paediatric areas and also to identify the types, frequency and rates of medication administration errors that occur despite the double-checking process. Double-checking by two nurses is an intervention used in many UK hospitals to prevent or reduce medication administration errors. There is, however, insufficient evidence to either support or refute the practice of double-checking in terms of medication error risk reduction. Prospective observational study. This was a prospective observational study of paediatric nurses' adherence to the double-checking process for medication administration from April-July 2012. Drug dose administration events (n = 2000) were observed. Independent drug dose calculation, rate of administering intravenous bolus drugs and labelling of flush syringes were the steps with lowest adherence rates. Drug dose calculation was only double-checked independently in 591 (30%) drug administrations. There was a statistically significant difference in nurses' adherence rate to the double-checking steps between weekdays and weekends in nine of the 15 evaluated steps. Medication administration errors (n = 191) or deviations from policy were observed, at a rate of 9·6% of drug administrations. These included 64 drug doses, which were left for parents to administer without nurse observation. There was variation between paediatric nurses' adherence to double-checking steps during medication administration. The most frequent type of administration errors or deviation from policy involved the medicine being given to the parents to administer to the child when the nurse was not present. © 2013 John Wiley & Sons Ltd.

Catalysts of Cu(II) and Co(II) ions adsorbed in chitosan used in transesterification of soy bean and babassu oils - a new route for biodiesel syntheses.

PubMed

da Silva, Rondinelly Brandão; Lima Neto, Alcides Fernandes; Soares Dos Santos, Lucas Samuel; de Oliveira Lima, José Renato; Chaves, Mariana Helena; Dos Santos, José Ribeiro; de Lima, Geraldo Magela; de Moura, Edmilson Miranda; de Moura, Carla Verônica Rodarte

2008-10-01

Catalysts of Cu(II) and Co(II) adsorbed in chitosan was used in transesterification of soy bean and babassu oils. The catalysts were characterized by infrared, atomic absorption and TG, and biodiesels was characterized by infrared, NMR, CG, TG, physic chemistry analysis. The maximum adsorption values found for copper and cobalt cations were 1.584 and 1.260mgg(-1), respectively, in 180min. However, conversion of oils in biodiesel was better when used Co(II) adsorbed in chitosan.

Neural and hybrid modeling: an alternative route to efficiently predict the behavior of biotechnological processes aimed at biofuels obtainment.

PubMed

Curcio, Stefano; Saraceno, Alessandra; Calabrò, Vincenza; Iorio, Gabriele

2014-01-01

The present paper was aimed at showing that advanced modeling techniques, based either on artificial neural networks or on hybrid systems, might efficiently predict the behavior of two biotechnological processes designed for the obtainment of second-generation biofuels from waste biomasses. In particular, the enzymatic transesterification of waste-oil glycerides, the key step for the obtainment of biodiesel, and the anaerobic digestion of agroindustry wastes to produce biogas were modeled. It was proved that the proposed modeling approaches provided very accurate predictions of systems behavior. Both neural network and hybrid modeling definitely represented a valid alternative to traditional theoretical models, especially when comprehensive knowledge of the metabolic pathways, of the true kinetic mechanisms, and of the transport phenomena involved in biotechnological processes was difficult to be achieved.

Neural and Hybrid Modeling: An Alternative Route to Efficiently Predict the Behavior of Biotechnological Processes Aimed at Biofuels Obtainment

PubMed Central

Saraceno, Alessandra; Calabrò, Vincenza; Iorio, Gabriele

2014-01-01

The present paper was aimed at showing that advanced modeling techniques, based either on artificial neural networks or on hybrid systems, might efficiently predict the behavior of two biotechnological processes designed for the obtainment of second-generation biofuels from waste biomasses. In particular, the enzymatic transesterification of waste-oil glycerides, the key step for the obtainment of biodiesel, and the anaerobic digestion of agroindustry wastes to produce biogas were modeled. It was proved that the proposed modeling approaches provided very accurate predictions of systems behavior. Both neural network and hybrid modeling definitely represented a valid alternative to traditional theoretical models, especially when comprehensive knowledge of the metabolic pathways, of the true kinetic mechanisms, and of the transport phenomena involved in biotechnological processes was difficult to be achieved. PMID:24516363

Effects of Cerebellar Disease on Sequences of Rapid Eye Movements

PubMed Central

King, Susan; Chen, Athena L.; Joshi, Anand; Serra, Alessandro; Leigh, R. John

2011-01-01

Summary Studying saccades can illuminate the more complex decision-making processes required for everyday movements. The double-step task, in which a target jumps to two successive locations before the subject has time to react, has proven a powerful research tool to investigate the brain’s ability to program sequential responses. We asked how patients with a range of cerebellar disorders responded to the double-step task, specifically, whether the initial saccadic response made to a target is affected by the appearance of a second target jump. We also sought to determine whether cerebellar patients were able to make corrective saccades towards the remembered second target location, if it were turned off soon after presentation. We tested saccades to randomly interleaved single- and double-step target jumps to eight locations on a circle. Patient’s initial responses to double-step stimuli showed 50% more error than saccades to single target jumps, and often, they failed to make a saccade to the first target jump. The presence of a second target jump had similar, but smaller effects in control subjects (error increased by 18%). During memory-guided double-step trials, both patients and controls made corrective saccades in darkness to the remembered location of the second jump. We conclude that in cerebellar patients, the second target jump interferes with programming of the saccade to the first target jump of a double-step stimulus; this defect highlights patients’ impaired ability to respond appropriately to sudden, conflicting changes in their environment. Conversely, since cerebellar patients can make corrective memory-guided saccades in darkness, they retain the ability to remember spatial locations, possibly due to non-retinal neural signals (corollary discharge) from cerebral hemispheric areas concerned with spatial localization. PMID:21385592

The neural basis of parallel saccade programming: an fMRI study.

PubMed

Hu, Yanbo; Walker, Robin

2011-11-01

The neural basis of parallel saccade programming was examined in an event-related fMRI study using a variation of the double-step saccade paradigm. Two double-step conditions were used: one enabled the second saccade to be partially programmed in parallel with the first saccade while in a second condition both saccades had to be prepared serially. The intersaccadic interval, observed in the parallel programming (PP) condition, was significantly reduced compared with latency in the serial programming (SP) condition and also to the latency of single saccades in control conditions. The fMRI analysis revealed greater activity (BOLD response) in the frontal and parietal eye fields for the PP condition compared with the SP double-step condition and when compared with the single-saccade control conditions. By contrast, activity in the supplementary eye fields was greater for the double-step condition than the single-step condition but did not distinguish between the PP and SP requirements. The role of the frontal eye fields in PP may be related to the advanced temporal preparation and increased salience of the second saccade goal that may mediate activity in other downstream structures, such as the superior colliculus. The parietal lobes may be involved in the preparation for spatial remapping, which is required in double-step conditions. The supplementary eye fields appear to have a more general role in planning saccade sequences that may be related to error monitoring and the control over the execution of the correct sequence of responses.

Doubled haploid production from Spanish onion (Allium cepa L.) germplasm: embryogenesis induction, plant regeneration and chromosome doubling.

PubMed

Fayos, Oreto; Vallés, María P; Garcés-Claver, Ana; Mallor, Cristina; Castillo, Ana M

2015-01-01

The use of doubled haploids in onion breeding is limited due to the low gynogenesis efficiency of this species. Gynogenesis capacity from Spanish germplasm, including the sweet cultivar Fuentes de Ebro, the highly pungent landrace BGHZ1354 and the two Valenciana type commercial varieties Recas and Rita, was evaluated and optimized in this study. The OH-1 population, characterized by a high gynogenesis induction, was used as control. Growing conditions of the donor plants were tested with a one-step protocol and field plants produced a slightly higher percentage of embryogenesis induction than growth chamber plants. A one-step protocol was compared with a two-step protocol for embryogenesis induction. Spanish germplasm produced a 2-3 times higher percentage of embryogenesis with the two-step protocol, Recas showing the highest percentage (2.09%) and Fuentes de Ebro the lowest (0.53%). These percentages were significantly lower than those from the OH-1 population, with an average of 15% independently of the protocol used. The effect of different containers on plant regeneration was tested using both protocols. The highest percentage of acclimated plants was obtained with the two-step protocol in combination with Eco2box (70%), whereas the lowest percentage was observed with glass tubes in the two protocols (20-23%). Different amiprofos-methyl (APM) treatments were applied to embryos for chromosome doubling. A similar number of doubled haploid plants were recovered with 25 or 50 μM APM in liquid medium. However, the application of 25 μM in solid medium for 24 h produced the highest number of doubled haploid plants. Somatic regeneration from flower buds of haploid and mixoploid plants proved to be a successful approach for chromosome doubling, since diploid plants were obtained from the four regenerated lines. In this study, doubled haploid plants were produced from the four Spanish cultivars, however further improvements are needed to increase their gynogenesis efficiency.

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.

Low cost heterogenous catalyst from (Achatina Fulica) snail shell and its application for biodiesel conversion via microwave irradiation

NASA Astrophysics Data System (ADS)

Fatimah, Is; Kurniastuti, E. A.; Basthiani, I. A.; Fakhri, A.

2017-11-01

Research on preparation of heterogenous catalyst from Achatina Fulica snail shell and its application biodiesel conversion has been investigation. Research aimed to obtain low cost and reusable catalyst for biodiesel production. The catalyst was prepared by grinding and calcining the snail shell at 900°C for 2 hours. The obtained solid was analysed by using XRD, SEM-EDX. FTIR, and also basicity measurement. Catalyst was used in the cenvertion of rice bran oil transesterification at varied volume of oil methanol ratio of 20-80 under microwave and reflux methode. The transesterification result were analyzed by using GCMS.

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.

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.

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.

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.

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

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.

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.

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.

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.

BBD Optimization of K-ZnO Catalyst Modification Process for Heterogeneous Transesterification of Rice Bran Oil to Biodiesel

NASA Astrophysics Data System (ADS)

Kabo, K. S.; Yacob, A. R.; Bakar, W. A. W. A.; Buang, N. A.; Bello, A. M.; Ruskam, A.

2016-07-01

Environmentally benign zinc oxide (ZnO) was modified with 0-15% (wt.) potassium through wet impregnation and used in transesterification of rice bran oil (RBO) to form biodiesel. The catalyst was characterized by X-Ray powder Diffraction (XRD), its basic sites determined by back titration and Response Surface Methodology (RSM) Box-Behnken Design (BBD) was used to optimize the modification process variables on the basic sites of the catalyst. The transesterification product, biodiesel was analyzed by Nuclear Magnetic Resonance (NMR) spectroscopy. The result reveals K-modified ZnO with highly increased basic sites. Quadratic model with high regression R2 = 0.9995 was obtained from the ANOVA of modification process, optimization at maximum basic sites criterion gave optimum modification conditions of K-loading = 8.5% (wt.), calcination temperature = 480 oC and time = 4 hours with response and basic sites = 8.14 mmol/g which is in close agreement with the experimental value of 7.64 mmol/g. The catalyst was used and a value of 95.53% biodiesel conversion was obtained and effect of potassium leaching was not significant in the process

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.

Discovery and characterizaton of a novel lipase with transesterification activity from hot spring metagenomic library.

PubMed

Yan, Wei; Li, Furong; Wang, Li; Zhu, Yaxin; Dong, Zhiyang; Bai, Linhan

2017-03-01

A new gene encoding a lipase (designated as Lip-1 ) was identified from a metagenomic bacterial artificial chromosome(BAC) library prepared from a concentrated water sample collected from a hot spring field in Niujie, Eryuan of Yunnan province in China. The open reading frame of this gene encoded 622 amino acid residues. It was cloned, fused with the oleosin gene and over expressed in Escherichia coli to prepare immobilized lipase artificial oil body AOB-sole-lip-1. The monomeric Sole-lip-1 fusion protein presented a molecular mass of 102.4 kDa. Enzyme assays using olive oil and methanol as the substrates in petroleum ether confirmed its transesterification activity. Hexadecanoic acid methyl ester, 8,11-Octadecadienoic acid methyl ester, 8-Octadecenoic acid methyl ester, and Octadecanoic acid methyl ester were detected. It showed favorable transesterification activity with optimal temperature 45 °C. Besides, the maximal biodiesel yield was obtained when the petroleum ether system as the organic solvent and the substrate methanol in 350 mmol/L (at a molar ratio of methanol of 10.5:1) and the water content was 1%. In light of these advantages, this lipase presents a promising resource for biodiesel production.

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.

Kinetic Evaluation of Lipid Oils Conversion to Biofuel Using Layered Double Hydroxide Doped with Triazabicyclodece Catalyst

NASA Astrophysics Data System (ADS)

Nato Lopez, Frank D.

Worldwide, there is an ever increasing need for sustainable, renewable fuels that will accommodate the rapidly increasing energy demand and provide independence from fossil fuels. The search for a sustainable alternative to petroleum based fuels has been a great challenge to the scientific community; therefore, great efforts are being made to overcome the fossil fuels dependence by exploring the prominent field of biofuels (bioethanol and biodiesel). Traditional biodiesel is produced from feedstocks such as vegetable oils and animal fats by converting the triglycerides with methanol in the presence of a homogeneous catalyst to produce fatty acid methyl esters (FAMEs). However, drawbacks of this process are the undesired glycerol byproduct and post reaction processing, including separation from reaction mixture, that results in high costs factors. In the present work, the reaction kinetics of a glycerol-free biodiesel method is studied. This method consists of the transesterification of a vegetable oil (i.e. canola oil) using dimethyl carbonate (DMC) as an alternative methylating agent in presence of layered double hydroxides doped with triazabicyclodecene catalyst (a basic organocatalyst). Furthermore, is theorized that this heterogeneous catalyst (TBD/LDH) simultaneously converts both FFAs and triglycerides due to acid sites formed by Al3+ active sites of the LDH structure. Additionally, the versatility of the Raman in situ technique was used as quantitative analysis tool to monitor the reaction kinetics and collect real time data.

Emissions of Jatropha oil-derived biodiesel blend fuels during combustion in a swirl burner

NASA Astrophysics Data System (ADS)

Norwazan, A. R.; Mohd. Jaafar, M. N.; Sapee, S.; Farouk, Hazir

2018-03-01

Experimental works on combustion of jatropha oil biodiesel blends of fuel with high swirling flow in swirl burner have been studied in various blends percentage. Jatropha oil biodiesel was produced using a two-step of esterification-transesterification process. The paper focuses on the emissions of biodiesel blends fuel using jatropha oil in lean through to rich air/fuel mixture combustion in swirl burner. The emissions performances were evaluated by using axial swirler amongst jatropha oil blends fuel including diesel fuel as baseline. The results show that the B25 has good emissions even though it has a higher emission of NOx than diesel fuel, while it emits as low as 42% of CO, 33% of SO2 and 50% of UHC emissions with high swirl number. These are due to the higher oxygen content in jatropha oil biodiesel.

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.

Improving Sorbents for Glycerol Capture in Biodiesel Refinement

PubMed Central

Johnson, Brandy J.; Melde, Brian J.; Moore, Martin H.; Malanoski, Anthony P.; Taft, Jenna R.

2017-01-01

Biodiesel is produced by transesterification of animal fat, vegetable oil, or waste cooking oil with alcohol. After production costs, the economic viability of biodiesel is dependent on what steps are necessary to remove impurities following synthesis and the effectiveness of quality control analysis. Solid-phase extraction offers a potentially advantageous approach in biodiesel processing applications. Nanoporous scaffolds were investigated for adsorption of glycerol, a side product of biodiesel synthesis that is detrimental to engine combustion when present. Materials were synthesized with varying pore wall composition, including ethane and diethylbenzene bridging groups, and sulfonated to promote hydrogen bonding interactions with glycerol. Materials bearing sulfonate groups throughout the scaffold walls as well as those post-synthetically grafted onto the surfaces show notably superior performance for uptake of glycerol. The sorbents are effective when used in biodiesel mixtures, removing greater than 90% of glycerol from a biodiesel preparation. PMID:28773042

Improving Sorbents for Glycerol Capture in Biodiesel Refinement.

PubMed

Johnson, Brandy J; Melde, Brian J; Moore, Martin H; Malanoski, Anthony P; Taft, Jenna R

2017-06-21

Biodiesel is produced by transesterification of animal fat, vegetable oil, or waste cooking oil with alcohol. After production costs, the economic viability of biodiesel is dependent on what steps are necessary to remove impurities following synthesis and the effectiveness of quality control analysis. Solid-phase extraction offers a potentially advantageous approach in biodiesel processing applications. Nanoporous scaffolds were investigated for adsorption of glycerol, a side product of biodiesel synthesis that is detrimental to engine combustion when present. Materials were synthesized with varying pore wall composition, including ethane and diethylbenzene bridging groups, and sulfonated to promote hydrogen bonding interactions with glycerol. Materials bearing sulfonate groups throughout the scaffold walls as well as those post-synthetically grafted onto the surfaces show notably superior performance for uptake of glycerol. The sorbents are effective when used in biodiesel mixtures, removing greater than 90% of glycerol from a biodiesel preparation.

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.

Dissecting Online Control in Developmental Coordination Disorder: A Kinematic Analysis of Double-Step Reaching

ERIC Educational Resources Information Center

Hyde, Christian; Wilson, Peter H.

2011-01-01

In a recent study, children with movement clumsiness (or Developmental Coordination Disorder--DCD) were shown to have difficulties making rapid online corrections when reaching, demonstrated by slower and less accurate movements to double-step targets (Hyde & Wilson, 2011). These results suggest that children with DCD have difficulty using…

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.

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.

Single-step electrochemical functionalization of double-walled carbon nanotube (DWCNT) membranes and the demonstration of ionic rectification

PubMed Central

2013-01-01

Carbon nanotube (CNT) membranes allow the mimicking of natural ion channels for applications in drug delivery and chemical separation. Double-walled carbon nanotube membranes were simply functionalized with dye in a single step instead of the previous two-step functionalization. Non-faradic electrochemical impedance spectra indicated that the functionalized gatekeeper by single-step modification can be actuated to mimic the protein channel under bias. This functional chemistry was proven by a highly efficient ion rectification, wherein the highest experimental rectification factor of ferricyanide was up to 14.4. One-step functionalization by electrooxidation of amine provides a simple and promising functionalization chemistry for the application of CNT membranes. PMID:23758999

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.

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.

Synthesis of zinc aluminate with high surface area by microwave hydrothermal method applied in the transesterification of soybean oil (biodiesel)

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

Quirino, M.R.; Oliveira, M.J.C.; Keyson, D.

Highlights: • ZnAl{sub 2}O{sub 4} spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min. • The powders show high specific surface area. • ZAT{sub b}15 showed activity of 52.22% for the conversion of soybean oil into biodiesel. - Abstract: Zinc aluminate is a material with high thermal stability and high mechanical strength that, owing to these properties, is used as a catalyst or support. In this work, zinc aluminate spinel was synthesized by the microwave hydrothermal method in only 15 or 30 min at a low temperature (150 °C) without templates, using only Al(NO{sub 3}){submore » 3}·9H{sub 2}O, Zn(NO{sub 3}){sub 2}·6H{sub 2}O, and urea as precursors and applied in the transesterification of soybean oil. X-ray diffraction analysis showed that ZnAl{sub 2}O{sub 4} had a cubic structure without secondary phases. The nitrogen adsorption measurements (BET) revealed a high surface area (266.57 m{sup 2} g{sup −1}) for the nanopowder synthesized in 15 min. This powder showed activity of 52.22% for the catalytic conversion of soybean oil into biodiesel by transesterification.« less

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.

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.

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%.

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.

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.

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.

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.

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

Facile fabrication of a stable and recyclable lipase@amine-functionalized ZIF-8 nanoparticles for esters hydrolysis and transesterification

NASA Astrophysics Data System (ADS)

Cheong, Ling-Zhi; Wei, Yayu; Wang, Hongbin; Wang, Zhiying; Su, Xiurong; Shen, Cai

2017-08-01

Zeolitic imidazolate frameworks (ZIF) represent one of the metal organic frameworks (MOF) with high potential for enzyme immobilization due to their exceptional chemical and thermal stability, negligible cytotoxicity, and easy synthesis under mild biocompatible conditions. Amine-functionalized ZIF-8 (An-ZIF-8) are capable of forming multipoint attachment via hydrogen bonding with lipase which will immobilize and further enhance stabilization of lipase. In addition, increased hydrophilicity of An-ZIF-8 will increase partitioning of An-ZIF-8 immobilized lipase at the aqueous/organic interface which enable lipase to expose its active site and retain its catalytic activity at its highest. Present study reports the use of ZIF-8 and An-ZIF-8 nanoparticles as carrier for Burkholderia cepacia lipase (BCL), compares the ester hydrolysis and transesterification activities of immobilized lipase with those of free lipase, and evaluates the reusability and recovery rate of the immobilized lipase. An-ZIF-8 nanoparticles (average 130.42 ± 0.55 nm) were facilely synthesized via mixing ZIF-8 nanoparticles with ammonia hydroxide solution. Despite having similar characteristics of high crystallinity and forming cuboid-like particles, An-ZIF-8 demonstrated significantly ( P < 0.05) lower Brunauer-Emmett-Teller (BET) surface area and higher thermal stability than ZIF-8. BCL were successfully immobilized on ZIF-8 (BCL@ZIF-8) and An-ZIF-8 (BCL@An-ZIF-8) nanoparticles with an average lipase loading rate of 8 mg/g MOF. The immobilized BCL demonstrated no significant differences in terms of esters hydrolysis and transesterification activities with those of free BCL. BCL@An-ZIF-8 demonstrated superior catalytic stability in comparison to BCL@ZIF-8 with retainment of more than 80% of its initial hydrolysis and transesterification activity for at least 10 repeated runs. In addition, more than 80% of the BCL@An-ZIF-8 can be easily recovered during each cycle of the reusability test through simple centrifugation.

Enzyme-catalyzed synthesis and kinetics of ultrasonic-assisted biodiesel production from waste tallow.

PubMed

Adewale, Peter; Dumont, Marie-Josée; Ngadi, Michael

2015-11-01

The use of ultrasonic processing was evaluated for its ability to achieve adequate mixing while providing sufficient activation energy for the enzymatic transesterification of waste tallow. The effects of ultrasonic parameters (amplitude, cycle and pulse) and major reaction factors (molar ratio and enzyme concentration) on the reaction kinetics of biodiesel generation from waste tallow bio-catalyzed by immobilized lipase [Candida antarctica lipase B (CALB)] were investigated. Three sets of experiments namely A, B, and C were conducted. In experiment set A, two factors (ultrasonic amplitude and cycle) were investigated at three levels; in experiment set B, two factors (molar ratio and enzyme concentration) were examined at three levels; and in experiment set C, two factors (ultrasonic amplitude and reaction time) were investigated at five levels. A Ping Pong Bi Bi kinetic model approach was employed to study the effect of ultrasonic amplitude on the enzymatic transesterification. Kinetic constants of transesterification reaction were determined at different ultrasonic amplitudes (30%, 35%, 40%, 45%, and 50%) and enzyme concentrations (4, 6, and 8 wt.% of fat) at constant molar ratio (fat:methanol); 1:6, and ultrasonic cycle; 5 Hz. Optimal conditions for ultrasound-assisted biodiesel production from waste tallow were fat:methanol molar ratio, 1:4; catalyst level 6% (w/w of fat); reaction time, 20 min (30 times less than conventional batch processes); ultrasonic amplitude 40% at 5 Hz. The kinetic model results revealed interesting features of ultrasound assisted enzyme-catalyzed transesterification (as compared to conventional system): at ultrasonic amplitude 40%, the reaction activities within the system seemed to be steady after 20 min which means the reaction could proceed with or without ultrasonic mixing. Reversed phase high performance liquid chromatography indicated the biodiesel yield to be 85.6±0.08%. Copyright © 2015 Elsevier B.V. All rights reserved.

Effect of double-layer application on dentin bond durability of one-step self-etch adhesives.

PubMed

Taschner, M; Kümmerling, M; Lohbauer, U; Breschi, L; Petschelt, A; Frankenberger, R

2014-01-01

The aim of this in vitro study was 1) to analyze the influence of a double-layer application technique of four one-step self-etch adhesive systems on dentin and 2) to determine its effect on the stability of the adhesive interfaces stored under different conditions. Four different one-step self-etch adhesives were selected for the study (iBondSE, Clearfil S(3) Bond, XenoV(+), and Scotchbond Universal). Adhesives were applied according to manufacturers' instructions or with a double-layer application technique (without light curing of the first layer). After bonding, resin-dentin specimens were sectioned for microtensile bond strength testing in accordance with the nontrimming technique and divided into 3 subgroups of storage: a) 24 hours (immediate bond strength, T0), b) six months (T6) in artificial saliva at 37°C, or c) five hours in 10 % NaOCl at room temperature. After storage, specimens were stressed to failure. Fracture mode was assessed under a light microscope. At T0, iBond SE showed a significant increase in microtensile bond strength when the double-application technique was applied. All adhesive systems showed reduced bond strengths after six months of storage in artificial saliva and after storage in 10% NaOCl for five hours; however at T6, iBond SE, Clearfil S(3) Bond, and XenoV(+) showed significantly higher microtensile bond strength results for the double-application technique compared with the single-application technique. Scotchbond Universal showed no difference between single- or double-application, irrespective of the storage conditions. The results of this study show that improvements in bond strength of one-step self-etch adhesives by using the double-application technique are adhesive dependent.

Physiological responses to single versus double stepping pattern of ascending the stairs.

PubMed

Aziz, Abdul Rashid; Teh, Kong Chuan

2005-07-01

The aim of this study was to compare the physiological responses and energy cost between two ascending patterns, the single-step (SS) and the double-step (DS), in climbing a public staircase. In the SS pattern, a person climbs one step at a time whilst in the double-step (DS) pattern, the individual traverses two steps in a single stride. Advocates of each stepping pattern claimed that their type of ascent is physically more taxing and expends more calories. Thirty subjects (10 males and 20 females) climbed a typical 11-storey flat (each step height of 0.15 m, a total of 180 steps and a vertical displacement of 27.0 m). The subjects climbed using either the SS pattern at a tempo of 100 steps x min(-1) or the DS pattern at 50 steps x min(-1). The prescribed stepping frequencies ensured that an equal amount of total work was performed between the SS and DS patterns. The climbing patterns were performed in random order. Physiological measures during the last 30 s of the climbs were used in the comparative analysis. The results showed that ventilation, oxygen uptake and heart rate values were significantly higher (all p < 0.01) in the SS as compared to the DS pattern. However, the caloric expenditure during the SS pattern was calculated to be only marginally higher than the DS pattern. In conclusion, ascending with the SS pattern led to significantly higher physiological responses compared to the DS pattern. The higher calorie expended with the SS compared to the DS pattern was deemed to be of little practical significance.

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.

Two-step rating-based 'double-faced applicability' test for sensory analysis of spread products as an alternative to descriptive analysis with trained panel.

PubMed

Kim, In-Ah; den-Hollander, Elyn; Lee, Hye-Seong

2018-03-01

Descriptive analysis with a trained sensory panel has thus far been the most well defined methodology to characterize various products. However, in practical terms, intensive training in descriptive analysis has been recognized as a serious defect. To overcome this limitation, various novel rapid sensory profiling methodologies have been suggested in the literature. Among these, attribute-based methodologies such as check-all-that-apply (CATA) questions showed results comparable to those of conventional sensory descriptive analysis. Kim, Hopkinson, van Hout, and Lee (2017a, 2017b) have proposed a novel attribute-based methodology termed the two-step rating-based 'double-faced applicability' test with a novel output measure of applicability magnitude (d' A ) for measuring consumers' product usage experience throughout various product usage stages. In this paper, the potential of the two-step rating-based 'double-faced applicability' test with d' A was investigated as an alternative to conventional sensory descriptive analysis in terms of sensory characterization and product discrimination. Twelve commercial spread products were evaluated using both conventional sensory descriptive analysis with a trained sensory panel and two-step rating-based 'double-faced applicability' test with an untrained sensory panel. The results demonstrated that the 'double-faced applicability' test can be used to provide a direct measure of the applicability magnitude of sensory attributes of the samples tested in terms of d' A for sensory characterization of individual samples and multiple sample comparisons. This suggests that when the appropriate list of attributes to be used in the questionnaire is already available, the two-step rating-based 'double-faced applicability' test with d' A can be used as a more efficient alternative to conventional descriptive analysis, without requiring any intensive training process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Spatiotemporal Parameters are not Substantially Influenced by Load Carriage or Inclination During Treadmill and Overground Walking

PubMed Central

Seay, Joseph F.; Gregorczyk, Karen N.; Hasselquist, Leif

2016-01-01

Abstract Influences of load carriage and inclination on spatiotemporal parameters were examined during treadmill and overground walking. Ten soldiers walked on a treadmill and overground with three load conditions (00 kg, 20 kg, 40 kg) during level, uphill (6% grade) and downhill (-6% grade) inclinations at self-selected speed, which was constant across conditions. Mean values and standard deviations for double support percentage, stride length and a step rate were compared across conditions. Double support percentage increased with load and inclination change from uphill to level walking, with a 0.4% stance greater increase at the 20 kg condition compared to 00 kg. As inclination changed from uphill to downhill, the step rate increased more overground (4.3 ± 3.5 steps/min) than during treadmill walking (1.7 ± 2.3 steps/min). For the 40 kg condition, the standard deviations were larger than the 00 kg condition for both the step rate and double support percentage. There was no change between modes for step rate standard deviation. For overground compared to treadmill walking, standard deviation for stride length and double support percentage increased and decreased, respectively. Changes in the load of up to 40 kg, inclination of 6% grade away from the level (i.e., uphill or downhill) and mode (treadmill and overground) produced small, yet statistically significant changes in spatiotemporal parameters. Variability, as assessed by standard deviation, was not systematically lower during treadmill walking compared to overground walking. Due to the small magnitude of changes, treadmill walking appears to replicate the spatiotemporal parameters of overground walking. PMID:28149338

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

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%.

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.

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

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.

Production of Biodiesel from Candlenut Oil Using a Two-step Co-solvent Method and Evaluation of Its Gaseous Emissions.

PubMed

Pham, Lan Ngoc; Luu, Boi Van; Phuoc, Hung Duong; Le, Hanh Ngoc Thi; Truong, Hoa Thi; Luu, Phuong Duc; Furuta, Masakazu; Imamura, Kiyoshi; Maeda, Yasuaki

2018-05-01

Candlenut oil (CNO) is a potentially new feedstock for biodiesel (BDF) production. In this paper, a two-step co-solvent method for BDF production from CNO was examined. Firstly, esterification of free fatty acids (FFAs) (7 wt%) present in CNO was carried out using a co-solvent of acetonitrile (30 wt%) and H 2 SO 4 as a catalyst. The content of FFAs was reduced to 0.8 wt% in 1 h at 65°C. Subsequent transesterification of the crude oil produced was carried out using a co-solvent of acetone (20 wt%) and 1 wt% potassium hydroxide (KOH). Ester content of 99.3% was obtained at 40°C in 45 min. The water content in BDF was 0.023% upon purification using vacuum distillation at 5 kPa. The components of CNO BDF were characterized using a Fourier-transform infrared spectrometry and gas chromatography-flame ionization detector. The physicochemical properties of BDF satisfied the ASTM D6751-02 standard. The gaseous exhaust emissions from the diesel engine upon combustion of the BDF blends (B0-B100) with petrodiesel were examined. The emissions of carbon monoxide and hydrocarbons were clearly lower, but that of nitrogen oxides was higher in comparison to those from petro-diesel.

Presidential Green Chemistry Challenge: 2003 Academic Award

EPA Pesticide Factsheets

Presidential Green Chemistry Challenge 2003 award winner, Professor Richard A. Gross, developed a transesterification to make polyol-containing polyesters using lipase, replacing heavy metal catalysts and hazardous solvents.

Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique.

PubMed

Mook, William R; Greenspoon, Joshua A; Millett, Peter J

2016-01-01

Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row. The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construct. The described technique includes the advantages of a double-row construct while also offering self reinforcement, decreased risk of suture cut through, decreased risk of medial row overtensioning and tissue strangulation, improved vascularity, the efficiency of a knotless system, and no increased risk for subacromial impingement from the burden of suture knots. Arthroscopic knotless double row rotator cuff repair is a safe and effective method to repair rotator cuff tears.

Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique

PubMed Central

Mook, William R.; Greenspoon, Joshua A.; Millett, Peter J.

2016-01-01

Background: Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row. Methods: The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construct. Results: The described technique includes the advantages of a double-row construct while also offering self reinforcement, decreased risk of suture cut through, decreased risk of medial row overtensioning and tissue strangulation, improved vascularity, the efficiency of a knotless system, and no increased risk for subacromial impingement from the burden of suture knots. Conclusion: Arthroscopic knotless double row rotator cuff repair is a safe and effective method to repair rotator cuff tears. PMID:27733881

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.

Transesterification of oil mixtures catalyzed by microencapsulated cutinase in reversed micelles.

PubMed

Badenes, Sara M; Lemos, Francisco; Cabral, Joaquim M S

2010-03-01

Recombinant cutinase from Fusarium solani pisi was used to catalyze the transesterification reaction between a mixture of triglycerides (oils) and methanol in reversed micelles of bis(2-ethylhexyl) sodium sulfosuccinate (AOT) in isooctane for the purposes of producing biodiesel. The use of a bi-phase lipase-catalyzed system brings advantages in terms of catalyst re-use and the control of water activity in the medium and around the enzyme micro-environment. Small-scale batch studies were performed to study the influence of the initial enzyme and alcohol concentrations, and the substrates molar ratio. Conversions in excess of 75 were obtained with reaction times under 24 h, which makes this enzymatic process highly competitive when compared to similar lipase catalyzed reactions for biodiesel production using methanol.

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.

High Glass Transition Temperature Renewable Polymers via Biginelli Multicomponent Polymerization.

PubMed

Boukis, Andreas C; Llevot, Audrey; Meier, Michael A R

2016-04-01

A novel and straightforward one-pot multicomponent polycondensation method was established in this work. The Biginelli reaction is a versatile multicomponent reaction of an aldehyde, a β-ketoester (acetoacetate) and urea, which can all be obtained from renewable resources, yielding diversely substituted 3,4-dihydropyrimidin-2(1H)-ones (DHMPs). In this study, renewable diacetoacetate monomers with different spacer chain lengths (C3, C6, C10, C20) were prepared via simple transesterification of renewable diols and commercial acetoacetates. The diacetoacetate monomers were then reacted with renewable dialdehydes, i.e., terephthalaldehyde and divanillin in a Biginelli type step-growth polymerization. The obtained DHMP polymers (polyDHMPs) displayed high molar masses, high glass transition temperatures (Tg) up to 203 °C and good thermal stability (Td5%) of 280 °C. The Tg of the polyDHMPs could be tuned by variation of the structure of the dialdehyde or the diacetoacetate component. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

An economically viable synthesis of biodiesel from a crude Millettia pinnata oil of Jharkhand, India as feedstock and crab shell derived catalyst.

PubMed

Madhu, Devarapaga; Chavan, Supriya B; Singh, Veena; Singh, Bhaskar; Sharma, Yogesh C

2016-08-01

Biodiesel has emerged as a prominent source to replace petroleum diesel. The cost incurred in the production of biodiesel is higher than that for refining of crude oil to obtain mineral diesel. The heterogeneous catalyst was prepared from crab shells by calcining the crushed mass at 800°C. The solid waste catalyst was characterized with XRD, XPS, BET, SEM-EDS, and FT-IR. Millettia pinnata (karanja) oil extracted from its seeds was used as a feedstock for the synthesis of biodiesel. Biodiesel was synthesized through esterification followed by transesterification in a two-step process. Characterization of biodiesel was done using proton NMR spectroscopy. Reaction parameters such as reaction time, reaction temperature, concentration of catalyst and stirrer speed were optimized. Reusability of catalyst was checked and found that there was no loss of catalytic activity up to five times. Copyright © 2016. Published by Elsevier Ltd.

Chemo-enzymatic synthesis of vinyl and l-ascorbyl phenolates and their inhibitory effects on advanced glycation end products.

PubMed

Hwang, Seung Hwan; Wang, Zhiqiang; Lim, Soon Sung

2017-01-01

This study successfully established the feasibility of a two-step chemo-enzymatic synthesis of l-ascorbyl phenolates. Intermediate vinyl phenolates were first chemically produced and then underwent trans-esterification with l-ascorbic acid in the presence of Novozyme 435® (Candida Antarctica lipase B) as a catalyst. Twenty vinyl phenolates and 11 ascorbyl phenolates were subjected to in vitro bioassays to investigate their inhibitory activity against advanced glycation end products (AGEs). Among them, vinyl 4-hydroxycinnamate (17VP), vinyl 4-hydroxy-3-methoxycinnamate (18VP), vinyl 4-hydroxy-3,5-dimethoxycinnamate (20VP), ascorbyl 4-hydroxy-3-methoxycinnamate (18AP) and ascorbyl 3,4-dimethoxycinnamate (19AP) showed 2-10 times stronger inhibitory activities than positive control (aminoguanidine and its precursors). These results indicated that chemo-enzymatically synthesized compounds have AGE inhibitory effect and thus are effective in either preventing or retarding glycation protein formation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Integration process of biodiesel production from filamentous oleaginous microalgae Tribonema minus.

PubMed

Wang, Hui; Gao, Lili; Chen, Lin; Guo, Fajin; Liu, Tianzhong

2013-08-01

Biodiesel production from microalgae has been receiving considerable attention. Past studies mainly relied on tiny sized single-cell oleaginous microalgal species, the biodiesel based on filamentous oleaginous microalgae was rarely reported. Thus, integrated process of biodiesel production from filamentous oleaginous microalgal strain Tribonema minus was studied in this work. The filamentous microalgae was cultivated for 21 days in 40 L glass panel, microalgae cells was harvested by DAF without any flocculants after the lipid content was 50.23%. After that, total lipid was extracted by subcritical ethanol from wet algal paste and 44.55% of crude lipid was triacylglycerols. Two-step catalytic conversion of pre-esterification and transesterification was adopted to convert the crude algal oil to biodiesel. The conversion rate of triacylglycerols reached 96.52% under the methanol to oil molar ratio of 12:1 during catalysis with 2% potassium hydroxide at 65°C for 30 min. The biodiesel product from T. minus conformed to Chinese National Standards. Copyright © 2013 Elsevier Ltd. All rights reserved.

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 Lipid of Phytoplankton Chaetoceros calcitrans through Ultrasonic Method

PubMed Central

Kwangdinata, Raymond; Raya, Indah; Zakir, Muhammad

2014-01-01

A research on production of biodiesel from lipid of phytoplankton Chaetoceros calcitrans through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extraction method using ethanol 96%, while biodiesel synthesis was carried out by transesterification reaction using methanol and KOH catalyst under sonication. Weight of biodiesel yield per biomass Chaetoceros calcitrans is 35.35%. Characterization of biodiesel was well carried out in terms of physical properties which are density and viscosity and chemical properties which are FFA content, saponification value, and iodine value. These values meet the American Society for Testing and Materials (ASTM D6751) standard levels, except for the viscosity value which was 1.14 g·cm−3. PMID:24688372

An updated comprehensive techno-economic analysis of algae biodiesel.

PubMed

Nagarajan, Sanjay; Chou, Siaw Kiang; Cao, Shenyan; Wu, Chen; Zhou, Zhi

2013-10-01

Algae biodiesel is a promising but expensive alternative fuel to petro-diesel. To overcome cost barriers, detailed cost analyses are needed. A decade-old cost analysis by the U.S. National Renewable Energy Laboratory indicated that the costs of algae biodiesel were in the range of $0.53-0.85/L (2012 USD values). However, the cost of land and transesterification were just roughly estimated. In this study, an updated comprehensive techno-economic analysis was conducted with optimized processes and improved cost estimations. Latest process improvement, quotes from vendors, government databases, and other relevant data sources were used to calculate the updated algal biodiesel costs, and the final costs of biodiesel are in the range of $0.42-0.97/L. Additional improvements on cost-effective biodiesel production around the globe to cultivate algae was also recommended. Overall, the calculated costs seem promising, suggesting that a single step biodiesel production process is close to commercial reality. Copyright © 2012 Elsevier Ltd. All rights reserved.

Adhesive-bonded scarf and stepped-lap joints

NASA Technical Reports Server (NTRS)

Hart-Smith, L. J.

1973-01-01

Continuum mechanics solutions are derived for the static load-carrying capacity of scarf and stepped-lap adhesive-bonded joints. The analyses account for adhesive plasticity and adherend stiffness imbalance and thermal mismatch. The scarf joint solutions include a simple algebraic formula which serves as a close lower bound, within a small fraction of a per cent of the true answer for most practical geometries and materials. Digital computer programs were developed and, for the stepped-lap joints, the critical adherend and adhesive stresses are computed for each step. The scarf joint solutions exhibit grossly different behavior from that for double-lap joints for long overlaps inasmuch as that the potential bond shear strength continues to increase with indefinitely long overlaps on the scarf joints. The stepped-lap joint solutions exhibit some characteristics of both the scarf and double-lap joints. The stepped-lap computer program handles arbitrary (different) step lengths and thickness and the solutions obtained have clarified potentially weak design details and the remedies. The program has been used effectively to optimize the joint proportions.

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.

Age-related changes in the center of mass velocity control during walking.

PubMed

Chong, Raymond K Y; Chastan, Nathalie; Welter, Marie-Laure; Do, Manh-Cuong

2009-07-10

During walking, the body center of mass oscillates along the vertical plane. Its displacement is highest at mid-swing and lowest at terminal swing during the transition to double support. Its vertical velocity (CoMv) has been observed to increase as the center of mass falls between mid- and late swing but is reduced just before double support. This suggests that braking of the center of mass is achieved with active neural control. We tested whether this active control deteriorates with aging (Experiment 1) and during a concurrent cognitive task (Experiment 2). At short steps of <0.4m, CoMv control was low and similar among all age groups. All groups braked the CoMv at longer steps of >0.4m but older subjects did so to a lesser extent. During the cognitive task, young subjects increased CoMv control (i.e. increase in CoMv braking) while maintaining step length and walking speed. Older subjects on the other hand, did not increase CoMv control but rather maintain it by reducing both step length and walking speed. These results suggest that active braking of the CoM during the transition to double support predominates in steps >0.4m. It could be a manifestation of the balance control system, since the braking occurs at late stance where body weight is being shifted to the contralateral side. The active braking mechanism also appears to require some attentional resource. In aging, reducing step length and speed are strategic to maintaining effective center of mass control during the transition to double support. However, the lesser degree of control in older adults indicates a true age-related deficit.

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...

Advanced Polymer Network Structures

DTIC Science & Technology

2016-02-01

double networks in a single step was identified from coarse-grained molecular dynamics simulations of polymer solvents bearing rigid side chains dissolved...in a polymer network. Coarse-grained molecular dynamics simulations also explored the mechanical behavior of traditional double networks and...DRI), polymer networks, polymer gels, molecular dynamics simulations , double networks 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

Double emulsions from a capillary array injection microfluidic device.

PubMed

Shang, Luoran; Cheng, Yao; Wang, Jie; Ding, Haibo; Rong, Fei; Zhao, Yuanjin; Gu, Zhongze

2014-09-21

A facile microfluidic device was developed by inserting an annular capillary array into a collection channel for single-step emulsification of double emulsions. By inserting multiple inner-phase solutions into the capillary array, multicomponent double emulsions or microcapsules with inner droplets of different content could also be obtained from the device.

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.

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.

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.

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.

Synthesis and evaluation of odour-active methionyl esters of fatty acids via esterification and transesterification of butter oil.

PubMed

Li, Cheng; Sun, Jingcan; Fu, Caili; Yu, Bin; Liu, Shao Quan; Li, Tianhu; Huang, Dejian

2014-02-15

Methionol-derived fatty acid esters were synthesised by both chemical and lipase catalysed esterification between fatty acids and methionol. Beneficial effects of both methods were compared qualitatively and quantitatively by GC-MS/GC-FID results. And the high acid and heat stability of our designed methionyl esters meet the requirement of the food industry. Most importantly, the sensory test showed that fatty acid carbon-chain length had an important effect on the flavour attributes of methionyl esters. Moreover, through Lipozyme TL IM-mediated transesterification, valuable methionol-derived esters were synthesised from the readily available natural material butter oil as the fatty acid source. The conversion of methionol and yield of each methionyl ester were also elucidated by GC-MS-FID. Copyright © 2013 Elsevier Ltd. All rights reserved.

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.

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

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

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.

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.)

Targeted mutations and MD simulations of a methanol-stable lipase YLIP9 from Yarrowia lipolytica MSR80 to develop a biodiesel enzyme.

PubMed

Syal, Poonam; Verma, Ved Vrat; Gupta, Rani

2017-11-01

Biodiesel, an environment friendly alternative for fuels, contains methyl esters of long-chain fatty acids. Our group has reported a methanol-stable YLIP9 from Yarrowia lipolytica MSR80 that shows poor catalysis of long-chain fatty acids. To shift its substrate specificity, residues within lid and binding pocket were identified for sequential mutations using YLIP2 as the template. Of the two point mutations (Glu116Leu and Ser119Val) introduced in the lid, the former mutation (YLIP9L1) increased the catalytic rate by ∼2-fold without any change in substrate specificity. In this mutant, six binding pocket residues (Bp2-Bp7) were further mutated to obtain six double mutants. YLIP9L1Bp3 showed significant shift in substrate specificity towards long-chain pNPesters with 11-fold increase in catalytic efficiency than YLIP9. Double mutations also led to increased thermostability and lowered activation energy of YLIP9L1Bp3 thereby shifting its optimum temperature from 60°C to 50°C. In silico molecular dynamics simulations revealed improved lid flexibility and increased catalytic triad volume in YLIP9L1Bp3. The enzyme YLIP9L1Bp3 was methanol-stable having selectivity for long-chain fatty acids with improved catalytic efficiency. Its application as a biodiesel enzyme was validated by transesterification of palm oil in presence of methanol, where it showed 8-fold increase in conversion of oil to methyl esters. Copyright © 2017 Elsevier B.V. All rights reserved.

Method for double-sided processing of thin film transistors

DOEpatents

Yuan, Hao-Chih; Wang, Guogong; Eriksson, Mark A.; Evans, Paul G.; Lagally, Max G.; Ma, Zhenqiang

2008-04-08

This invention provides methods for fabricating thin film electronic devices with both front- and backside processing capabilities. Using these methods, high temperature processing steps may be carried out during both frontside and backside processing. The methods are well-suited for fabricating back-gate and double-gate field effect transistors, double-sided bipolar transistors and 3D integrated circuits.

Double C-NOT attack and counterattack on `Three-step semi-quantum secure direct communication protocol'

NASA Astrophysics Data System (ADS)

Gu, Jun; Lin, Po-hua; Hwang, Tzonelih

2018-07-01

Recently, Zou and Qiu (Sci China Phys Mech Astron 57:1696-1702, 2014) proposed a three-step semi-quantum secure direct communication protocol allowing a classical participant who does not have a quantum register to securely send his/her secret message to a quantum participant. However, this study points out that an eavesdropper can use the double C-NOT attack to obtain the secret message. To solve this problem, a modification is proposed.

A comparison between atmospheric/humidity and vacuum cyanoacrylate fuming of latent fingermarks.

PubMed

Farrugia, Kevin J; Fraser, Joanna; Friel, Lauren; Adams, Duncan; Attard-Montalto, Nicola; Deacon, Paul

2015-12-01

A number of pseudo-operational trials were set up to compare the atmospheric/humidity and vacuum cyanoacrylate fuming processes on plastic carrier bags. The fuming processes were compared using two-step cyanoacrylate fuming with basic yellow 40 (BY40) staining and a one-step fluorescent cyanoacrylate fuming, Lumicyano 4%. Preliminary work using planted fingermarks and split depletions were performed to identify the optimum vacuum fuming conditions. The first pseudo-operational trial compared the different fuming conditions (atmospheric/humidity vs. vacuum) for the two-step process where an additional 50% more marks were detected with the atmospheric/humidity process. None of the marks by the vacuum process could be observed visually; however, a significant number of marks were detected by fluorescence after BY40 staining. The second trial repeated the same work in trial 1 using the one-step cyanoacrylate process, Lumicyano at a concentration of 4%. Trial 2 provided comparable results to trial 1 and all the items were then re-treated with Lumicyano 4% at atmospheric/humidity conditions before dyeing with BY40 to provide the sequences of process A (Lumicyano 4% atmospheric-Lumicyano 4% atmospheric-BY40) and process B (Lumicyano 4% vacuum-Lumicyano 4% atmospheric-BY40). The number of marks (visual and fluorescent) was counted after each treatment with a substantial increase in the number of detected marks in the second and third treatments of the process. The increased detection rate after the double Lumicyano process was unexpected and may have important implications. Trial 3 was performed to investigate whether the amount of cyanoacrylate and/or fuming time had an impact on the results observed in trial 2 whereas trial 4 assessed if the double process using conventional cyanoacrylate, rather than Lumicyano 4%, provided an increased detection rate. Trials 3 and 4 confirmed that doubling the amount of Lumicyano 4% cyanoacrylate and fuming time produced a lower detection rate than the double process with Lumicyano 4%. Furthermore, the double process with conventional cyanoacrylate did not provide any benefit. Scanning electron microscopy was also performed to investigate the morphology of the cyanoacrylate polymer under different conditions. The atmospheric/humidity process appears to be superior to the vacuum process for both the two-step and one-step cyanoacrylate fuming, although the two-step process performed better in comparison to the one-step process under vacuum conditions. Nonetheless, the use of vacuum cyanoacrylate fuming may have certain operational advantages and its use does not adversely affect subsequent cyanoacrylate fuming with atmospheric/humidity conditions. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

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

Layered double hydroxide stability. 2. Formation of Cr(III)-containing layered double hydroxides directly from solution

NASA Technical Reports Server (NTRS)

Boclair, J. W.; Braterman, P. S.; Jiang, J.; Lou, S.; Yarberry, F.

1999-01-01

Solutions containing divalent metal [M(II) = Mg2+, Zn2+, Co2+, Ni2+, Mn2+] chlorides and CrCl3 6H2O were titrated with NaOH to yield, for M(II) = Zn, Co, and Ni, hydrotalcite-like layered double hydroxides (LDHs), [[M(II)]1-z[Cr(III)]z(OH)2][Cl]z yH2O, in a single step, without intermediate formation of chromium hydroxide. Analysis of the resultant titration curves yields solubility constants for these compounds. These are in the order Zn < Ni approximately Co, with a clear preference for formation of the phase with z = 1/3. With Mg2+ as chloride, titration gives a mixture of Cr(OH)3 and Mg(OH)2, but the metal sulfates give Mg2Cr(OH)6 1/2(SO4) by a two-step process. Titrimetric and spectroscopic evidence suggests short-range cation order in the one-step LDH systems.

Production of Renewable Diesel Fuel

DOT National Transportation Integrated Search

2012-06-01

Vegetable oils have been investigated as a way to provide a renewable source for diesel fuel. A successful approach to using : vegetable oils in diesel engines has been transesterification of the oils with simple alcohols to produce mono-alkyl esters...

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.

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

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.

Performance of structured lipids incorporating selected phenolic and ascorbic acids.

PubMed

Gruczynska, Eliza; Przybylski, Roman; Aladedunye, Felix

2015-04-15

Conditions applied during frying require antioxidant which is stable at these conditions and provides protection for frying oil and fried food. Novel structured lipids containing nutraceuticals and antioxidants were formed by enzymatic transesterification, exploring canola oil and naturally occurring antioxidants such as ascorbic and selected phenolic acids as substrates. Lipozyme RM IM lipase from Rhizomucor miehei was used as biocatalyst. Frying performance and oxidative stability of the final transesterification products were evaluated. The novel lipids showed significantly improved frying performance compared to canola oil. Oxidative stability assessment of the structured lipids showed significant improvement in resistance to oxidative deterioration compared to original canola oil. Interestingly, the presence of ascorbic acid in an acylglycerol structure protected α-tocopherol against thermal degradation, which was not observed for the phenolic acids. Developed structured lipids containing nutraceuticals and antioxidants may directly affect nutritional properties of lipids also offering nutraceutical ingredients for food formulation. Copyright © 2014 Elsevier Ltd. All rights reserved.

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.

Evaluation of hydrolysis-esterification biodiesel production from wet microalgae.

PubMed

Song, Chunfeng; Liu, Qingling; Ji, Na; Deng, Shuai; Zhao, Jun; Li, Shuhong; Kitamura, Yutaka

2016-08-01

Wet microalgae hydrolysis-esterification route has the advantage to avoid the energy-intensive units (e.g. drying and lipid extraction) in the biodiesel production process. In this study, techno-economic evaluation of hydrolysis-esterification biodiesel production process was carried out and compared with conventional (usually including drying, lipid extraction, esterification and transesterification) biodiesel production process. Energy and material balance of the conventional and hydrolysis-esterification processes was evaluated by Aspen Plus. The simulation results indicated that drying (2.36MJ/L biodiesel) and triolein transesterification (1.89MJ/L biodiesel) are the dominant energy-intensive stages in the conventional route (5.42MJ/L biodiesel). By contrast, the total energy consumption of hydrolysis-esterification route can be reduced to 1.81MJ/L biodiesel, and approximately 3.61MJ can be saved to produce per liter biodiesel. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

Biosynthesis of glycerol carbonate from glycerol by lipase in dimethyl carbonate as the solvent.

PubMed

Lee, Kyung Hwa; Park, Chang-Ho; Lee, Eun Yeol

2010-11-01

Glycerol carbonate was synthesized from renewable glycerol and dimethyl carbonate using lipase in solvent-free reaction system in which excess dimethyl carbonate played as the reaction medium. A variety of lipases have been tested for their abilities to catalyze transesterification reaction, and Candida antartica lipase B and Novozyme 435 exhibited higher catalytic activities. The silica-coated glycerol with a 1:1 ratio was supplied to prevent two-phase formation between hydrophobic dimethyl carbonate and hydrophilic glycerol. Glycerol carbonate was successfully synthesized with more than 90% conversion from dimethyl carbonate and glycerol with a molar ratio of 10 using Novozyme 435-catalyzed transesterification at 70 °C. The Novozyme 435 [5% (w/w) and 20% (w/w)] and silica gel were more than four times recycled with good stability in a repeated batch operation for the solvent-free synthesis of glycerol carbonate.

Prediction of normalized biodiesel properties by simulation of multiple feedstock blends.

PubMed

García, Manuel; Gonzalo, Alberto; Sánchez, José Luis; Arauzo, Jesús; Peña, José Angel

2010-06-01

A continuous process for biodiesel production has been simulated using Aspen HYSYS V7.0 software. As fresh feed, feedstocks with a mild acid content have been used. The process flowsheet follows a traditional alkaline transesterification scheme constituted by esterification, transesterification and purification stages. Kinetic models taking into account the concentration of the different species have been employed in order to simulate the behavior of the CSTR reactors and the product distribution within the process. The comparison between experimental data found in literature and the predicted normalized properties, has been discussed. Additionally, a comparison between different thermodynamic packages has been performed. NRTL activity model has been selected as the most reliable of them. The combination of these models allows the prediction of 13 out of 25 parameters included in standard EN-14214:2003, and confers simulators a great value as predictive as well as optimization tool. (c) 2010 Elsevier Ltd. All rights reserved.

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

Cellulose acetate fibers prepared from different raw materials with rapid synthesis method.

PubMed

Chen, Jinghuan; Xu, Jikun; Wang, Kun; Cao, Xuefei; Sun, Runcang

2016-02-10

Transesterification is a mild process to prepare cellulose acetate (CA) as compared with the traditional method. In this study, CA fibers were produced from six cellulose raw materials based on a simple and rapid transesterification method. The properties of the CA solutions and the obtained CA fibers were investigated in detail. Results showed that all of the cellulose raw materials were esterified within 15 min, and spinning dopes could be obtained by concentrating the CA solutions via vacuum distillation. The XRD, FT-IR, (1)H, (13)C and HSQC NMR analysis confirmed the successful synthesis of CA. The degree of substitution (DS) of the obtained CA was significantly affected by the degree of polymerization (DP) of cellulose raw materials, which further influenced the viscosity of CA solutions as well as the structural, thermal and mechanical properties of the CA fibers. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

Bio-diesel production directly from the microalgae biomass of Nannochloropsis by microwave and ultrasound radiation.

PubMed

Koberg, Miri; Cohen, Moshe; Ben-Amotz, Ami; Gedanken, Aharon

2011-03-01

This work offers an optimized method for the direct conversion of harvested Nannochloropsis algae into bio-diesel using two novel techniques. The first is a unique bio-technology-based environmental system utilizing flue gas from coal burning power stations for microalgae cultivation. This method reduces considerably the cost of algae production. The second technique is the direct transesterification (a one-stage method) of the Nannochloropsis biomass to bio-diesel production using microwave and ultrasound radiation with the aid of a SrO catalyst. These two techniques were tested and compared to identify the most effective bio-diesel production method. Based on our results, it is concluded that the microwave oven method appears to be the most simple and efficient method for the one-stage direct transesterification of the as-harvested Nannochloropsis algae. Copyright © 2010 Elsevier Ltd. All rights reserved.

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.

Evaluation of Method-Specific Extraction Variability for the Measurement of Fatty Acids in a Candidate Infant/Adult Nutritional Formula Reference Material.

PubMed

Place, Benjamin J

2017-05-01

To address community needs, the National Institute of Standards and Technology has developed a candidate Standard Reference Material (SRM) for infant/adult nutritional formula based on milk and whey protein concentrates with isolated soy protein called SRM 1869 Infant/Adult Nutritional Formula. One major component of this candidate SRM is the fatty acid content. In this study, multiple extraction techniques were evaluated to quantify the fatty acids in this new material. Extraction methods that were based on lipid extraction followed by transesterification resulted in lower mass fraction values for all fatty acids than the values measured by methods utilizing in situ transesterification followed by fatty acid methyl ester extraction (ISTE). An ISTE method, based on the identified optimal parameters, was used to determine the fatty acid content of the new infant/adult nutritional formula reference material.

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.

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.

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).

Butanolysis: Comparison of potassium hydroxide and potassium tert-butoxide as catalyst for biodiesel preparing from rapeseed oil.

PubMed

Musil, Martin; Skopal, Frantisek; Hájek, Martin; Vavra, Ales

2018-07-15

Biodiesel is a mixture of esters of fatty acids (most often palmitic, stearic and oleic) and lower alcohols (in our work butanol) produced by transesterification. It is a renewable source of energy, prepared from triacylglycerides, which are contained in vegetable oils and animal fats. This work focuses on alkaline catalyzed transesterification of rapeseed oil with butanol and comparison of two catalysts (potassium hydroxide and potassium tert-butoxide). In industry is usually transesterification of rapeseed oil carried out like reaction catalyzed by potassium hydroxide. Potassium hydroxide have high content of K 2 CO 3 , KHCO 3 and water. Moreover water is formed by neutralization of potassium hydroxide with free fatty acids contained in oil. In cause of tert-butoxide catalyzed reaction, it is not possible because tert-butoxide have not a OH - aniont, which is needed for water forming. The influence of various conditions (addition of water, temperature of separation, intensity of stirring and type of catalyst) on butanolysis process was studied for both catalysts. For both catalysts dependence of conversions on time were plotted. When tert-butoxide was used, satisfactory phase separation was not achieved. The only way was separation of hot crude reaction mixture without adding water. Ester formed by this method had high content of free glycerol and soaps, but reached higher conversion. The best results were obtained with KOH and subsequent separation of cold crude reaction mixture with the addition of water and slow stirring. The difference between reactions catalyzed by potassium hydroxide and potassium tert-butoxide was described. Copyright © 2018 Elsevier Ltd. All rights reserved.

Solvent Free Transesterification of Glycerol Into Glycerol Carbonate Over Nanostructured CaAl Hydrotalcite Catalyst.

PubMed

Devarajan, Arulselvan; Thiripuranthagan, Sivakumar; Radhakrishnan, Ramakrishnan; Kumaravel, Sakthivel

2018-07-01

Drastic increase in green house gases due to fossil fuels usage urges the mankind to look for alternative fuel resources. Biodiesel is one of the alternative fuels which attracted the attention of many researchers. In recent years, bio-diesel drags much attention as an alternative clean fuel. Glycerol is an unavoidable byproduct in the transesterification process of vegetable oils into bio diesel and therefore market is flooded with glycerol. So it is high time to find ways of utilizing the abundant glycerol into value added products. Herein we report the catalytic transesterification of glycerol using dimethyl carbonate over MgAl-hydrotalcite (MgAl-HT), CaAl-hydrotalcite (CaAl-HT) and nano structured CaAl-HT catalysts. All the catalysts were characterized by XRD, FT-IR, TPD-CO2, BET, SEM and HR-TEM techniques. Among them Ca4Al-HT was found to be best in terms of conversion of glycerol (82.4%) and selectivity (95.9%) towards glycerol carbonate. The effect of CTAB template concentration in the nano synthesis of Ca4Al-HT on conversion and selectivity was studied and Ca4Al-HT synthesized with 0.4 moles of CTAB showed the best conversion of glycerol (98.7%) and the highest selectivity towards glycerol carbonate (97.9%). The recyclability test performed with the best catalyst showed that the catalyst was recyclable even after 5 cycles. Valorization of glycerol yields glycerol carbonate (GC) which is a very good polar solvent with high boiling point, building block in several organic syntheses and used in the production of surfactants, poly urethanes etc.

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.

Supercritical water reformation of crude glycerol solution for hydrogen production.

DOT National Transportation Integrated Search

2009-12-01

Glycerol, also known as glycerin, is a less desirable byproduct formed in the production of biodiesel via the transesterification otriglycerides and presents a nontrivial issue in terms of developing other beneficial end uses. With an inflated glycer...

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...

Biodiesel

USDA-ARS?s Scientific Manuscript database

Biodiesel is a renewable alternative to petrodiesel that is prepared from plant oils or animal fats. Biodiesel is prepared via transesterification and the resulting fuel properties must be compliant with international fuel standards such as ASTM D6751 and EN 14214. Numerous catalysts, methods, and l...

Double layer mixed matrix membrane adsorbers improving capacity and safety hemodialysis

NASA Astrophysics Data System (ADS)

Saiful; Borneman, Z.; Wessling, M.

2018-05-01

Double layer mixed matrix membranes adsorbers have been developed for blood toxin removal by embedding activated carbon into cellulose acetate macroporous membranes. The membranes are prepared by phase inversion method via water vapor induced phase separation followed by an immersion precipitation step. Double layer MMM consisting of an active support and a separating layer. The active support layer consists of activated carbon particles embedded in macroporous cellulose acetate; the separating layer consists of particle free cellulose acetate. The double layer membrane possess an open and interconnected macroporous structure with a high loading of activated carbon available for blood toxins removal. The MMM AC has a swelling degree of 6.5 %, porosity of 53 % and clean water flux of 800 Lm-2h-1bar-1. The prepared membranes show a high dynamic Creatinine (Crt) removal during hemodilysis process. The Crt removal by adsorption contributes to amore than 83 % of the total removal. The double layer adsorptive membrane proves hemodialysis membrane can integrated with adsorption, in which blood toxins are removed in one step.

Double exposure using 193nm negative tone photoresist

NASA Astrophysics Data System (ADS)

Kim, Ryoung-han; Wallow, Tom; Kye, Jongwook; Levinson, Harry J.; White, Dave

2007-03-01

Double exposure is one of the promising methods for extending lithographic patterning into the low k I regime. In this paper, we demonstrate double patterning of k 1-effective=0.25 with improved process window using a negative resist. Negative resist (TOK N- series) in combination with a bright field mask is proven to provide a large process window in generating 1:3 = trench:line resist features. By incorporating two etch transfer steps into the hard mask material, frequency doubled patterns could be obtained.

Numerical calculation on a two-step subdiffusion behavior of lateral protein movement in plasma membranes

NASA Astrophysics Data System (ADS)

Sumi, Tomonari; Okumoto, Atsushi; Goto, Hitoshi; Sekino, Hideo

2017-10-01

A two-step subdiffusion behavior of lateral movement of transmembrane proteins in plasma membranes has been observed by using single-molecule experiments. A nested double-compartment model where large compartments are divided into several smaller ones has been proposed in order to explain this observation. These compartments are considered to be delimited by membrane-skeleton "fences" and membrane-protein "pickets" bound to the fences. We perform numerical simulations of a master equation using a simple two-dimensional lattice model to investigate the heterogeneous diffusion dynamics behavior of transmembrane proteins within plasma membranes. We show that the experimentally observed two-step subdiffusion process can be described using fence and picket models combined with decreased local diffusivity of transmembrane proteins in the vicinity of the pickets. This allows us to explain the two-step subdiffusion behavior without explicitly introducing nested double compartments.

Age-related changes in gait adaptability in response to unpredictable obstacles and stepping targets.

PubMed

Caetano, Maria Joana D; Lord, Stephen R; Schoene, Daniel; Pelicioni, Paulo H S; Sturnieks, Daina L; Menant, Jasmine C

2016-05-01

A large proportion of falls in older people occur when walking. Limitations in gait adaptability might contribute to tripping; a frequently reported cause of falls in this group. To evaluate age-related changes in gait adaptability in response to obstacles or stepping targets presented at short notice, i.e.: approximately two steps ahead. Fifty older adults (aged 74±7 years; 34 females) and 21 young adults (aged 26±4 years; 12 females) completed 3 usual gait speed (baseline) trials. They then completed the following randomly presented gait adaptability trials: obstacle avoidance, short stepping target, long stepping target and no target/obstacle (3 trials of each). Compared with the young, the older adults slowed significantly in no target/obstacle trials compared with the baseline trials. They took more steps and spent more time in double support while approaching the obstacle and stepping targets, demonstrated poorer stepping accuracy and made more stepping errors (failed to hit the stepping targets/avoid the obstacle). The older adults also reduced velocity of the two preceding steps and shortened the previous step in the long stepping target condition and in the obstacle avoidance condition. Compared with their younger counterparts, the older adults exhibited a more conservative adaptation strategy characterised by slow, short and multiple steps with longer time in double support. Even so, they demonstrated poorer stepping accuracy and made more stepping errors. This reduced gait adaptability may place older adults at increased risk of falling when negotiating unexpected hazards. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparative toxicity and mutagenicity of biodiesel exhaust

EPA Science Inventory

Biodiesel (BD) is commercially made from the transesterification of plant and animal derived oils. The composition of biodiesel exhaust (BE) depends on the type of fuel, the blend ratio and the engine and operating conditions. While numerous studies have characterized the health ...

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…

Natural wax organogels for cookies

USDA-ARS?s Scientific Manuscript database

Organogels formed from vegetable oil and an organogelator have drawn great interest as alternatives to trans fats. Unlike the current alternatives to trans fats such as tropical oils, fully hydrogenated oils and their transesterifed oils containing high contents of saturated fats, organogels can be ...

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 Novel Double-Layer Nanostructures of SiC–WOxby a Two Step Thermal Evaporation Process

PubMed Central

2009-01-01

A novel double-layer nanostructure of silicon carbide and tungsten oxide is synthesized by a two-step thermal evaporation process using NiO as the catalyst. First, SiC nanowires are grown on Si substrate and then high density W18O49nanorods are grown on these SiC nanowires to form a double-layer nanostructure. XRD and TEM analysis revealed that the synthesized nanostructures are well crystalline. The growth of W18O49nanorods on SiC nanowires is explained on the basis of vapor–solid (VS) mechanism. The reasonably better turn-on field (5.4 V/μm) measured from the field emission measurements suggest that the synthesized nanostructures could be used as potential field emitters. PMID:20596292

CryoEM structure of the spliceosome immediately after branching

PubMed Central

Galej, Wojciech P.; Wilkinson, Max E.; Fica, Sebastian M.; Oubridge, Chris; Newman, Andrew J.; Nagai, Kiyoshi

2016-01-01

Pre-mRNA splicing proceeds by two consecutive trans-esterification reactions via a lariat-intron intermediate. We present the 3.8Å cryoEM structure of the spliceosome immediately after lariat formation. The 5’-splice site is cleaved but remains close to the catalytic Mg2+ site in the U2/U6 snRNA triplex, and the 5’-phosphate of the intron nucleotide G(+1) is linked to the branch adenosine 2’OH. The 5’-exon is held between the Prp8 N-terminal and Linker domains, and base-pairs with U5 snRNA loop 1. Non-Watson-Crick interactions between the branch helix and 5’-splice site dock the branch adenosine into the active site, while intron nucleotides +3 to +6 base-pair with the U6 snRNA ACAGAGA sequence. Isy1 and the step one factors Yju2 and Cwc25 stabilise docking of the branch helix. The intron downstream of the branch site emerges between the Prp8 RT and Linker domains and extends towards Prp16 helicase, suggesting a plausible mechanism of remodelling before exon ligation. PMID:27459055

Conversion of polar and non-polar algae oil lipids to fatty acid methyl esters with solid acid catalysts--A model compound study.

PubMed

Asikainen, Martta; Munter, Tony; Linnekoski, Juha

2015-09-01

Bio-based fuels are becoming more and more important due to the depleting fossil resources. The production of biodiesel from algae oil is challenging compared to terrestrial vegetable oils, as algae oil consists of polar fatty acids, such as phospholipids and glycolipids, as well as non-polar triglycerides and free fatty acids common in vegetable oils. It is shown that a single sulphonated solid acid catalyst can perform the esterification and transesterification reactions of both polar and non-polar lipids. In mild reaction conditions (60-70 °C) Nafion NR50 catalyst produces methyl palmitate (FAME) from the palmitic acid derivatives of di-, and tri-glyceride, free fatty acid, and phospholipid with over 80% yields, with the glycolipid derivative giving nearly 40% yields of FAME. These results demonstrate how the polar and non-polar lipid derivatives of algal oil can be utilised as feedstocks for biodiesel production with a single catalyst in one reaction step. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

Microalgae as a feedstock for biofuel precursors and value-added products: Green fuels and golden opportunities

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

Tang, Yuting; Rosenberg, Julian N.; Bohutskyi, Pavlo

In this study, the prospects of biofuel production from microalgal carbohydrates and lipids coupled with greenhouse gas mitigation due to photosynthetic assimilation of CO 2 have ushered in a renewed interest in algal feedstock. Furthermore, microalgae (including cyanobacteria) have become established as commercial sources of value-added biochemicals such as polyunsaturated fatty acids and carotenoid pigments used as antioxidants in nutritional supplements and cosmetics. This article presents a comprehensive synopsis of the metabolic basis for accumulating lipids as well as applicable methods of lipid and cellulose bioconversion and final applications of these natural or refined products from microalgal biomass. For lipids,more » one-step in situ transesterification offers a new and more accurate approach to quantify oil content. As a complement to microalgal oil fractions, the utilization of cellulosic biomass from microalgae to produce bioethanol by fermentation, biogas by anaerobic digestion, and bio-oil by hydrothermal liquefaction are discussed. Collectively, a compendium of information spanning green renewable fuels and value-added nutritional compounds is provided.« less

Microalgae as a feedstock for biofuel precursors and value-added products: Green fuels and golden opportunities

DOE PAGES

Tang, Yuting; Rosenberg, Julian N.; Bohutskyi, Pavlo; ...

2015-11-16

In this study, the prospects of biofuel production from microalgal carbohydrates and lipids coupled with greenhouse gas mitigation due to photosynthetic assimilation of CO 2 have ushered in a renewed interest in algal feedstock. Furthermore, microalgae (including cyanobacteria) have become established as commercial sources of value-added biochemicals such as polyunsaturated fatty acids and carotenoid pigments used as antioxidants in nutritional supplements and cosmetics. This article presents a comprehensive synopsis of the metabolic basis for accumulating lipids as well as applicable methods of lipid and cellulose bioconversion and final applications of these natural or refined products from microalgal biomass. For lipids,more » one-step in situ transesterification offers a new and more accurate approach to quantify oil content. As a complement to microalgal oil fractions, the utilization of cellulosic biomass from microalgae to produce bioethanol by fermentation, biogas by anaerobic digestion, and bio-oil by hydrothermal liquefaction are discussed. Collectively, a compendium of information spanning green renewable fuels and value-added nutritional compounds is provided.« less

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.

Intracorporeal Double-J stent placement during robot-assisted urinary tract reconstruction: technical considerations.

PubMed

Mufarrij, Patrick W; Rajamahanty, Srinivas; Krane, L Spencer; Hemal, Ashok K

2012-09-01

An integral component of many urologic reconstructive surgical procedures is the positioning of a Double-J stent to span the anastomosis. Some surgeons prefer to place a retrograde stent during cystoscopy, either during or after the reconstruction. In this communication, we describe our straightforward and effective approach of performing this critical step intracorporeally using robotic assistance in a variety of upper tract urologic reconstructive procedures. We examined our Institutional Review Board-approved database of robotic surgeries to identify reconstructive operations that included the intracorporeal placement of a Double-J stent since 2008. Our step-by-step method for stent placement during various robotic urologic reconstructions is detailed, including procedures involving the proximal, mid, and distal ureter. With the aid of a bedside assistant-surgeon, we delineate how the console surgeon is able to perform this step of the procedure completely intracorporeally, without the need for repositioning or cystoscopy. Since the inception of our robotic surgical program in 2008, we have used these robotic stent placement techniques in 150 patients. The average time of robotic intracorporeal stent placement across the anastomosis was 3.5 minutes. Three patients did experience proximal stent migration, as documented on postoperative radiographs, but all were treated with conservative measures, because their anastomosis was not affected and severe symptoms did not develop. No patient needed stent replacement, and each stent was subsequently removed ureteroscopically without sequelae. Our robotic intracorporeal Double-J stent placement approach is simple and effective, avoids the need for cystoscopy and fluoroscopy, and can be used in any type of upper urinary tract urologic reconstruction.

Theoretical and experimental study of a gas-coupled two-stage pulse tube cooler with stepped warm displacer as the phase shifter

NASA Astrophysics Data System (ADS)

Pang, Xiaomin; Wang, Xiaotao; Dai, Wei; Li, Haibing; Wu, Yinong; Luo, Ercang

2018-06-01

A compact and high efficiency cooler working at liquid hydrogen temperature has many important applications such as cooling superconductors and mid-infrared sensors. This paper presents a two-stage gas-coupled pulse tube cooler system with a completely co-axial configuration. A stepped warm displacer, working as the phase shifter for both stages, has been studied theoretically and experimentally in this paper. Comparisons with the traditional phase shifter (double inlet) are also made. Compared with the double inlet type, the stepped warm displacer has the advantages of recovering the expansion work from the pulse tube hot end (especially from the first stage) and easily realizing an appropriate phase relationship between the pressure wave and volume flow rate at the pulse tube hot end. Experiments are then carried out to investigate the performance. The pressure ratio at the compression space is maintained at 1.37, for the double inlet type, the system obtains 1.1 W cooling power at 20 K with 390 W acoustic power input and the relative Carnot efficiency is only 3.85%; while for the stepped warm displacer type, the system obtains 1.06 W cooling power at 20 K with only 224 W acoustic power input and the relative Carnot efficiency can reach 6.5%.

Impact of biodiesel source material and chemical structure on emissions of criteria pollutants from a heavy-duty engine.

PubMed

McCormick, R L; Graboski, M S; Alleman, T L; Herring, A M; Tyson, K S

2001-05-01

Biodiesel is an oxygenated diesel fuel made from vegetable oils and animal fats by conversion of the triglyceride fats to esters via transesterification. In this study we examined biodiesels produced from a variety of real-world feedstocks as well as pure (technical grade) fatty acid methyl and ethyl esters for emissions performance in a heavy-duty truck engine. The objective was to understand the impact of biodiesel chemical structure, specifically fatty acid chain length and number of double bonds, on emissions of NOx and particulate matter (PM). A group of seven biodiesels produced from real-world feedstocks and 14 produced from pure fatty acids were tested in a heavy-duty truck engine using the U.S. heavy-duty federal test procedure (transient test). It was found that the molecular structure of biodiesel can have a substantial impact on emissions. The properties of density, cetane number, and iodine number were found to be highly correlated with one another. For neat biodiesels, PM emissions were essentially constant at about 0.07 g/bhp-h for all biodiesels as long as density was less than 0.89 g/cm3 or cetane number was greater than about 45. NOx emissions increased with increasing fuel density or decreasing fuel cetane number. Increasing the number of double bonds, quantified as iodine number, correlated with increasing emissions of NOx. Thus the increased NOx observed for some fuels cannot be explained by the NOx/PM tradeoff and is therefore not driven by thermal NO formation. For fully saturated fatty acid chains the NOx emission increased with decreasing chain length for tests using 18, 16, and 12 carbon chain molecules. Additionally, there was no significant difference in NOx or PM emissions for the methyl and ethyl esters of identical fatty acids.

Sequential double photodetachment of He- in elliptically polarized laser fields

NASA Astrophysics Data System (ADS)

Génévriez, Matthieu; Dunseath, Kevin M.; Terao-Dunseath, Mariko; Urbain, Xavier

2018-02-01

Four-photon double detachment of the helium negative ion is investigated experimentally and theoretically for photon energies where the transient helium atom is in the 1 s 2 s 3S or 1 s 2 p P3o states, which subsequently ionize by absorption of three photons. Ionization is enhanced by intermediate resonances, giving rise to series of peaks in the He+ spectrum, which we study in detail. The He+ yield is measured in the wavelength ranges from 530 to 560 nm and from 685 to 730 nm and for various polarizations of the laser light. Double detachment is treated theoretically as a sequential process, within the framework of R -matrix theory for the first step and effective Hamiltonian theory for the second step. Experimental conditions are accurately modeled, and the measured and simulated yields are in good qualitative and, in some cases, quantitative agreement. Resonances in the double detachment spectra can be attributed to well-defined Rydberg states of the transient atom. The double detachment yield exhibits a strong dependence on the laser polarization which can be related to the magnetic quantum number of the intermediate atomic state. We also investigate the possibility of nonsequential double detachment with a two-color experiment but observe no evidence for it.

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...

Biodiesel: A fuel, a lubricant, and a solvent

USDA-ARS?s Scientific Manuscript database

Biodiesel is well-known as a biogenic alternative to conventional diesel fuel derived from petroleum. It is produced from feedstocks such as plant oils consisting largely of triacylglycerols through transesterification with an alcohol such as methanol. The properties of biodiesel are largely compet...

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...

Bill sets NSF on path to double its budget

NASA Astrophysics Data System (ADS)

Showstack, Randy

The US. National Science Foundation (NSF) is one step closer to having its budget more than doubled over the next five years, thanks to legislation approved 14 November by both houses of Congress.President George W. Bush is expected to sign the bill into law.

Effects of acute alcohol intoxication on automated processing: evidence from the double-step paradigm.

PubMed

Vorstius, Christian; Radach, Ralph; Lang, Alan R

2012-02-01

Reflexive and voluntary levels of processing have been studied extensively with respect to possible impairments due to alcohol intoxication. This study examined alcohol effects at the 'automated' level of processing essential to many complex visual processing tasks (e.g., reading, visual search) that involve ongoing modifications or reprogramming of well-practiced routines. Data from 30 participants (16 male) were collected in two counterbalanced sessions (alcohol vs. no-alcohol control; mean breath alcohol concentration = 68 mg/dL vs. 0 mg/dL). Eye movements were recorded during a double-step task where 75% of trials involved two target stimuli in rapid succession (inter-stimulus interval [ISI]=40, 70, or 100 ms) so that they could elicit two distinct saccades or eye movements (double steps). On 25% of trials a single target appeared. Results indicated that saccade latencies were longer under alcohol. In addition, the proportion of single-step responses and the mean saccade amplitude (length) of primary saccades decreased significantly with increasing ISI. The key novel finding, however, was that the reprogramming time needed to cancel the first saccade and adjust saccade amplitude was extended significantly by alcohol. The additional time made available by prolonged latencies due to alcohol was not utilized by the saccade programming system to decrease the number of two-step responses. These results represent the first demonstration of specific alcohol-induced programming deficits at the automated level of oculomotor processing.

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.

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

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.

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.

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.

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.

Propyl gallate synthesis using acidophilic tannase and simultaneous production of tannase and gallic acid by marine Aspergillus awamori BTMFW032.

PubMed

Beena, P S; Basheer, Soorej M; Bhat, Sarita G; Bahkali, Ali H; Chandrasekaran, M

2011-07-01

Marine Aspergillus awamori BTMFW032, recently reported by us, produce acidophilic tannase as extracellular enzyme. Here, we report the application of this enzyme for synthesis of propyl gallate by direct transesterification of tannic acid and in tea cream solubilisation besides the simultaneous production of gallic acid along with tannase under submerged fermentation by this fungus. This acidophilic tannase enabled synthesis of propyl gallate by direct transesterification of tannic acid using propanol as organic reaction media under low water conditions. The identity of the product was confirmed with thin layer chromatography and Fourier transform infrared spectroscopy. It was noted that 699 U/ml of enzyme could give 60% solubilisation of tea cream within 1 h. Enzyme production medium was optimized adopting Box-Behnken design for simultaneous synthesis of tannase and gallic acid. Process variables including tannic acid, sodium chloride, ferrous sulphate, dipotassium hydrogen phosphate, incubation period and agitation were recognized as the critical factors that influenced tannase and gallic acid production. The model obtained predicted 4,824.61 U/ml of tannase and 136.206 μg/ml gallic acid after 48 h of incubation, whereas optimized medium supported 5,085 U/ml tannase and 372.6 μg/ml of gallic acid production after 36 and 84 h of incubation, respectively, with a 15-fold increase in both enzyme and gallic acid production. Results indicated scope for utilization of this acidophilic tannase for transesterification of tannic acid into propyl gallate, tea cream solubilisation and simultaneous production of gallic acid along with tannase.

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.

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.

Thickness dependence of the levitation performance of double-layer high-temperature superconductor bulks above a magnetic rail

NASA Astrophysics Data System (ADS)

Sun, R. X.; Zheng, J.; Liao, X. L.; Che, T.; Gou, Y. F.; He, D. B.; Deng, Z. G.

2014-10-01

A double-layer high-temperature superconductor (HTSC) arrangement was proposed and proved to be able to bring improvements to both levitation force and guidance force compared with present single-layer HTSC arrangement. To fully exploit the applied magnetic field by a magnetic rail, the thickness dependence of a double-layer HTSC arrangement on the levitation performance was further investigated in the paper. In this study, the lower-layer bulk was polished step by step to different thicknesses, and the upper-layer bulk with constant thickness was directly superimposed on the lower-layer one. The levitation force and the force relaxation of the double-layer HTSC arrangement were measured above a Halbach magnetic rail. Experimental result shows that a bigger levitation force and a less levitation force decay could be achieved by optimizing the thickness of the lower-layer bulk HTSC. This thickness optimization method could be applied together with former reported double-layer HTSC arrangement method with aligned growth sector boundaries pattern. This series of study on the optimized combination method do bring a significant improvement on the levitation performance of present HTS maglev systems.

Anther Culture in Eggplant (Solanum melongena L.).

PubMed

Rotino, Giuseppe Leonardo

2016-01-01

The technique of in vitro anther culture is the most favorite to incite the production of plants from microspore through direct embryogenesis or regeneration from callus. Anther culture has been employed since 1980s in eggplant to obtain double-haploid plants from microspore derived embryos. From that time it has been refined and widely applied both at commercial level for a fast generation double-haploid parental lines of F1 hybrids, as well as for experimental studies as the complete homozygosis of the microspore-derived plants make more simply the genetic analysis. In this chapter, a step-by-step procedure is reported, taking into consideration all the aspects of the technique, including the growth condition of the anther donor plant, the in vitro regeneration of the androgenetic plantlets, their ploidy analysis, and the colchicine treatment to double the chromosome number of the haploids.

Facile synthesis of nickel-cobalt double hydroxide nanosheets with high rate capability for application in supercapacitor

NASA Astrophysics Data System (ADS)

Wang, Minmin; Xue, Junying; Zhang, Fangming; Ma, Wenle; Cui, Hongtao

2015-02-01

In this work, nickel-cobalt double hydroxide nanosheets with high rate capability are prepared by a facile epoxide precipitation route. The synthetic procedure includes an oxidization step using ammonium persulfate as oxidant and a precipitation step using propylene oxide as precipitation agent. As shown in the results of electrochemical characterization, high specific capacitance of 2548 F g-1 for this material can be obtained at current density of 0.9 A g-1 in aqueous solution of 3 mol L-1 KOH. It is surprising to notice that the capacitance of material still remains 1587 F g-1 at high current density of 35.7 A g-1. These results demonstrate that the as-prepared nickel-cobalt double hydroxide nanosheets are promising electrode material for supercapacitor application as a primary power source.

Transesterified tyrosol and hydroxytyrosol alkyl esters from cuphea oil – antioxidant behavior in Liposomes

USDA-ARS?s Scientific Manuscript database

Tyrosol and hydroxytyrosol are the antioxidant molecules abundantly found in olive oil. Transesterification of tyrosol and hydroxytyrosol with cuphea oil results in medium chain alkyl esters with antioxidant properties. Membrane partitioning, antioxidant capacity, and membrane location of these nove...

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Solvo-thermal in situ transesterification of wet spent coffee grounds for the production of biodiesel.

PubMed

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

2018-02-01

This work addresses non-catalytic biodiesel production from spent coffee ground (SCG) by integrating solvo-thermal effect of 1,2-dichloroethane (DCE) with in situ transesterification over 160 °C. The SCG water content has a positive effect on the DCE hydrolysis up to 60 wt% due to the bimolecular substitution mechanism. The hydrolysis gives an acidic environment favorable for cellulose decomposition, SCG particle size reduction and lipid conversion. The optimal fatty acid ethyl ester yield was 11.8 wt% based on the mass of dried SCG with 3.36 ml ethanol and 3.16 ml DCE at 196.8 °C through the response surface methodology. Using the solvo-thermal effect, direct utilization of wet SCG as a biodiesel feedstock provides not only economic feasibility without using drying process and additional acid catalyst but also environmental advantage of recycling the municipal waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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.

Biodiesel production from transesterification of palm oil with methanol over CaO supported on bimodal meso-macroporous silica catalyst.

PubMed

Witoon, Thongthai; Bumrungsalee, Sittisut; Vathavanichkul, Peerawut; Palitsakun, Supaphorn; Saisriyoot, Maythee; Faungnawakij, Kajornsak

2014-03-01

Calcium oxide-loaded porous materials have shown promise as catalysts in transesterification. However, the slow diffusion of bulky triglycerides through the pores limited the activity of calcium oxide (CaO). In this work, bimodal meso-macroporous silica was used as a support to enhance the accessibility of the CaO dispersed inside the pores. Unimodal porous silica having the identical mesopore diameter was employed for the purpose of comparison. Effects of CaO content and catalyst pellet size on the yield of fatty acid methyl esters (FAME) were investigated. The basic strength was found to increase with increasing the CaO content. The CaO-loaded bimodal porous silica catalyst with the pellet size of 325μm achieved a high %FAME of 94.15 in the first cycle, and retained an excellent %FAME of 88.87 after five consecutive cycles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Biodiesel production from Spirulina microalgae feedstock using direct transesterification near supercritical methanol condition.

PubMed

Mohamadzadeh Shirazi, Hamed; Karimi-Sabet, Javad; Ghotbi, Cyrus

2017-09-01

Microalgae as a candidate for production of biodiesel, possesses a hard cell wall that prevents intracellular lipids leaving out from the cells. Direct or in situ supercritical transesterification has the potential for destruction of microalgae hard cell wall and conversion of extracted lipids to biodiesel that consequently reduces the total energy consumption. Response surface methodology combined with central composite design was applied to investigate process parameters including: Temperature, Time, Methanol-to-dry algae, Hexane-to-dry algae, and Moisture content. Thirty-two experiments were designed and performed in a batch reactor, and biodiesel efficiency between 0.44% and 99.32% was obtained. According to fatty acid methyl ester yields, a quadratic experimental model was adjusted and the significance of parameters was evaluated using analysis of variance (ANOVA). Effects of single and interaction parameters were also interpreted. In addition, the effect of supercritical process on the ultrastructure of microalgae cell wall using scanning electron spectrometry (SEM) was surveyed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Physical Properties of Nyamplung Oil (Calophyllum inophyllum L) for Biodiesel Production

NASA Astrophysics Data System (ADS)

Dewang, Syamsir; Suriani; Hadriani, Siti; Bannu; Abdullah, B.

2017-05-01

Worldwide energy crisis due to the too high of energy consumption causes the people trying to find alternative energy to support energy requirements. The use of energy from environmentally friendly plant-based materials into an effort to assist communities in sufficient of national energy needs. Some processing of Nyamplung (Calophyllum inophyllum L) oil production is drying and pressing to produce crude oil. Degumming process is then performed to remove the sap contained in the oil. The next process is to remove free fatty acids (FFA) below 2% that can cause corrosion on the machine when in use. The results performed of the density properties quality to produce oil that appropriate with the international standards by time variation of catalyst. The result was obtained the density value of 0.92108 gr/cm3 at the time of 3 hours by trans-esterification process, and the best yield value was measured at 98.2% in 2 hours stirring of transesterification.

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

[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.

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.

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.

Effects of preparation steps on the physical parameters and electromechanical properties of IPMC actuators

NASA Astrophysics Data System (ADS)

Wang, Yanjie; Zhu, Zicai; Chen, Hualing; Luo, Bin; Chang, Longfei; Wang, Yongquan; Li, Dichen

2014-12-01

The electromechanical properties of ionic polymer-metal composites (IPMC) are affected by many factors, including resistivity of surface electrodes, bending stiffness and dielectric modulus, etc, which are closely related to physical and chemical preparation steps. This paper focuses on the effects of preparation steps on these physical parameters and electromechanical properties of IPMC actuators. The mechanisms of electrode formation in the preparation steps are also clarified and investigated. To obtain samples with different features, one or more of the crucial process steps, including pretreatment, impregnation-reduction and chemical plating, were selected to fabricate IPMC. The experimental observations revealed that the physical parameters of IPMC strongly depend on their electrode morphologies caused by different steps, which were reasonable from the standpoint of physics. IPMC with the characteristics of low surface resistance and low bending stiffness, and a large area of interface electrode exhibits a perfect performance. The improvements were considered to be attributed to the double-layer electrostatic effect, induced by the broad dispersion of penetrated electrode nanoparticles. An electrical component, consisting of an equivalent circuit of a parallel combination of the serial circuit of the resistance and the electric double-layer capacitance, is introduced to qualitatively explain the deformation behaviors of IPMC. This research helps to improve the preparation steps and promote the understanding of IPMC.

Dynamic Circuitry for Updating Spatial Representations: III. From Neurons to Behavior

PubMed Central

Berman, Rebecca A.; Heiser, Laura M.; Dunn, Catherine A.; Saunders, Richard C.; Colby, Carol L.

2008-01-01

Each time the eyes move, the visual system must adjust internal representations to account for the accompanying shift in the retinal image. In the lateral intraparietal cortex (LIP), neurons update the spatial representations of salient stimuli when the eyes move. In previous experiments, we found that split-brain monkeys were impaired on double-step saccade sequences that required updating across visual hemifields, as compared to within hemifield (Berman et al. 2005; Heiser et al. 2005). Here we describe a subsequent experiment to characterize the relationship between behavioral performance and neural activity in LIP in the split-brain monkey. We recorded from single LIP neurons while split-brain and intact monkeys performed two conditions of the double-step saccade task: one required across-hemifield updating and the other within-hemifield updating. We found that, despite extensive experience with the task, the split-brain monkeys were significantly more accurate for within-hemifield as compared to across-hemifield sequences. In parallel, we found that population activity in LIP of the split-brain monkeys was significantly stronger for within-hemifield as compared to across-hemifield conditions of the double-step task. In contrast, in the normal monkey, both the average behavioral performance and population activity showed no bias toward the within-hemifield condition. Finally, we found that the difference between within-hemifield and across-hemifield performance in the split-brain monkeys was reflected at the level of single neuron activity in LIP. These findings indicate that remapping activity in area LIP is present in the split-brain monkey for the double-step task and co-varies with spatial behavior on within-hemifield compared to across-hemifield sequences. PMID:17493922

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...

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…

Synthesis and tribological investigation of lipoyl glycerides

USDA-ARS?s Scientific Manuscript database

Lipoyl glycerides (LG) were synthesized by enzymatic transesterification of lipoic acid (LA) with high oleic sunflower oil (HOSuO) in 2-methyl-2-butanol solvent. The synthesis gave a crude product mixture (LGc) comprising unreacted LA, free fatty acids (FFA), and various LG structures with varying d...

Enzymatic monoesterification of symmetric diols: restriction of molecular conformations influences selectivity.

PubMed

Tomer, Sanjiv O; Soni, Hemant P

2017-10-31

We have experimentally demonstrated that by 'locking' the molecular conformation through the introduction of a double or triple bond in the center of a symmetric diol, enzymatic monoesterification can be achieved selectively. The enzyme Candida antarctica lipase B, generally used for the transesterification of diols, can be effectively used for the monoesterification of symmetrical diols in an unbuffered system also. By varying the chain length of a carboxylic acid moiety, we have established that optimum selectivity and efficiency can be achieved in the range of 4.8 to 5.0 pK a values. Selectivity can be improved up to 98.75% for a monoester in an overall 73% yield (mixture of a monoester and a diester) when but-2-yne-1,4-diol reacted with hexanoic acid. Water, a by-product, provides an interfacial environment for the enzyme to work in the organic reaction medium. The uniqueness of the reported monoesterification protocol is that it involves only the mechanical stirring of the reaction mixture at room temperature in the presence of the enzyme for 24 h. High percentage yield with selectivity for a monoester, easier product isolation and overall, environmental sustainability are added advantages. The synthesized monoesters are characterized by using HNMR and high resolution mass spectrometry (HRMS).

The effects of processing techniques on magnesium-based composite

NASA Astrophysics Data System (ADS)

Rodzi, Siti Nur Hazwani Mohamad; Zuhailawati, Hussain

2016-12-01

The aim of this study is to investigate the effect of processing techniques on the densification, hardness and compressive strength of Mg alloy and Mg-based composite for biomaterial application. The control sample (pure Mg) and Mg-based composite (Mg-Zn/HAp) were fabricated through mechanical alloying process using high energy planetary mill, whilst another Mg-Zn/HAp composite was fabricated through double step processing (the matrix Mg-Zn alloy was fabricated by planetary mill, subsequently HAp was dispersed by roll mill). As-milled powder was then consolidated by cold press into 10 mm diameter pellet under 400 MPa compaction pressure before being sintered at 300 °C for 1 hour under the flow of argon. The densification of the sintered pellets were then determined by Archimedes principle. Mechanical properties of the sintered pellets were characterized by microhardness and compression test. The results show that the density of the pellets was significantly increased by addition of HAp, but the most optimum density was observed when the sample was fabricated through double step processing (1.8046 g/cm3). Slight increment in hardness and ultimate compressive strength were observed for Mg-Zn/HAp composite that was fabricated through double step processing (58.09 HV, 132.19 MPa), as compared to Mg-Zn/HAp produced through single step processing (47.18 HV, 122.49 MPa).

Esterification and transesterification of greases to fatty acid methyl esters with highly active diphanylammonium salts

USDA-ARS?s Scientific Manuscript database

We have conducted an investigation designed to identify alternate catalysts for the production of fatty acid methyl esters (FAME) to be used as biodiesel. Diphenylammonium sulfate (DPAS) and diphenylammonium chloride (DPA-HCl) salts were found to be highly active homogeneous catalysts for the simu...

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...

Modeling the Crystallization Behavior of Biodiesel at Low Temperatures

USDA-ARS?s Scientific Manuscript database

The most common form of biodiesel is made by transesterification of vegetable oil or animal fat fatty acids with methanol (FAME). Biodiesel from feedstocks such as palm oil (PME), rapeseed oil (RME), soybean oil (SME) or used cooking oil (UCOME) is susceptible to performance issues during cold weat...

Effects of monoacylglycerols on kinematic viscosity and cold filter plugging point of methyl soyate

USDA-ARS?s Scientific Manuscript database

Biodiesel is an alternative fuel composed of mono-alkyl fatty acid esters made from the transesterification of plant oils or animal fats with methanol or ethanol. After conversion, biodiesel may contain trace concentrations of unconverted monoacylglycerols (MAG). These MAG have low solubility in bio...

Branched-chain fatty acid methyl esters as cold flow improvers for biodiesel

USDA-ARS?s Scientific Manuscript database

Biodiesel is an alternative diesel fuel derived mainly from the transesterification of plant oils with methanol or ethanol. This fuel is generally made from commodity oils such as canola, palm, or soybean and has a number of properties that make it compatible in compression-ignition engines. Despite...

Generation and characterization of diesel engine combustion emissions from petroleum diesel and soybean biodiesel fuels and application for inhalation exposure studies

EPA Science Inventory

Biodiesel made from the transesterification of plant- and anmal-derived oils is an important alternative fuel source for diesel engines. Although numerous studies have reported health effects associated with petroleum diesel emissions, information on biodiesel emissions are more ...

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…

Kl-impregnated Oyster Shells as a Solid Catalyst for Soybean Oil Transesterificaton

USDA-ARS?s Scientific Manuscript database

Research on inexpensive and green catalysts is needed for economical production of biodiesel. The goal of the research was to test KI-impregnated oyster shell as a solid catalyst for transesterification of soybean oil. Specific objectives were to characterize KI-impregnated oyster shell, determine t...

Scanning Shack-Hartmann wavefront sensor

NASA Astrophysics Data System (ADS)

Molebny, Vasyl V.

2004-09-01

Criss-crossing of focal images is the cause of a narrow dynamic range in Shack-Hartmann sensors. Practically, aberration range wider than +/-3 diopters can not be measured. A method has been proposed for ophthalmologic applications using a rarefied lenslet array through which a wave front is projected with the successive step-by-step changing of the global tilt. The data acquired in each step are accumulated and processed. In experimental setup, a doubled dynamic range was achieved with four steps of wave front tilting.

Precision Tests of a Quantum Hall Effect Device DC Equivalent Circuit Using Double-Series and Triple-Series Connections

PubMed Central

Jeffery, A.; Elmquist, R. E.; Cage, M. E.

1995-01-01

Precision tests verify the dc equivalent circuit used by Ricketts and Kemeny to describe a quantum Hall effect device in terms of electrical circuit elements. The tests employ the use of cryogenic current comparators and the double-series and triple-series connection techniques of Delahaye. Verification of the dc equivalent circuit in double-series and triple-series connections is a necessary step in developing the ac quantum Hall effect as an intrinsic standard of resistance. PMID:29151768

Front and backside processed thin film electronic devices

DOEpatents

Yuan, Hao-Chih; Wang, Guogong; Eriksson, Mark A.; Evans, Paul G.; Lagally, Max G.; Ma, Zhenqiang

2010-10-12

This invention provides methods for fabricating thin film electronic devices with both front- and backside processing capabilities. Using these methods, high temperature processing steps may be carried out during both frontside and backside processing. The methods are well-suited for fabricating back-gate and double-gate field effect transistors, double-sided bipolar transistors and 3D integrated circuits.

Challenges facing lithium batteries and electrical double-layer capacitors.

PubMed

Choi, Nam-Soon; Chen, Zonghai; Freunberger, Stefan A; Ji, Xiulei; Sun, Yang-Kook; Amine, Khalil; Yushin, Gleb; Nazar, Linda F; Cho, Jaephil; Bruce, Peter G

2012-10-01

Energy-storage technologies, including electrical double-layer capacitors and rechargeable batteries, have attracted significant attention for applications in portable electronic devices, electric vehicles, bulk electricity storage at power stations, and "load leveling" of renewable sources, such as solar energy and wind power. Transforming lithium batteries and electric double-layer capacitors requires a step change in the science underpinning these devices, including the discovery of new materials, new electrochemistry, and an increased understanding of the processes on which the devices depend. The Review will consider some of the current scientific issues underpinning lithium batteries and electric double-layer capacitors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Active site electrostatics protect genome integrity by blocking abortive hydrolysis during DNA recombination

PubMed Central

Ma, Chien-Hui; Rowley, Paul A; Macieszak, Anna; Guga, Piotr; Jayaram, Makkuni

2009-01-01

Water, acting as a rogue nucleophile, can disrupt transesterification steps of important phosphoryl transfer reactions in DNA and RNA. We have unveiled this risk, and identified safeguards instituted against it, during strand cleavage and joining by the tyrosine site-specific recombinase Flp. Strand joining is threatened by a latent Flp endonuclease activity (type I) towards the 3′-phosphotyrosyl intermediate resulting from strand cleavage. This risk is not alleviated by phosphate electrostatics; neutralizing the negative charge on the scissile phosphate through methylphosphonate (MeP) substitution does not stimulate type I endonuclease. Rather, protection derives from the architecture of the recombination synapse and conformational dynamics within it. Strand cleavage is protected against water by active site electrostatics. Replacement of the catalytic Arg-308 of Flp by alanine, along with MeP substitution, elicits a second Flp endonuclease activity (type II) that directly targets the scissile phosphodiester bond in DNA. MeP substitution, combined with appropriate active site mutations, will be useful in revealing anti-hydrolytic mechanisms engendered by systems that mediate DNA relaxation, DNA transposition, site-specific recombination, telomere resolution, RNA splicing and retrohoming of mobile introns. PMID:19440204

A Review of Enzymatic Transesterification of Microalgal Oil-Based Biodiesel Using Supercritical Technology

PubMed Central

Taher, Hanifa; Al-Zuhair, Sulaiman; Al-Marzouqi, Ali H.; Haik, Yousef; Farid, Mohammed M.

2011-01-01

Biodiesel is considered a promising replacement to petroleum-derived diesel. Using oils extracted from agricultural crops competes with their use as food and cannot realistically satisfy the global demand of diesel-fuel requirements. On the other hand, microalgae, which have a much higher oil yield per hectare, compared to oil crops, appear to be a source that has the potential to completely replace fossil diesel. Microalgae oil extraction is a major step in the overall biodiesel production process. Recently, supercritical carbon dioxide (SC-CO2) has been proposed to replace conventional solvent extraction techniques because it is nontoxic, nonhazardous, chemically stable, and inexpensive. It uses environmentally acceptable solvent, which can easily be separated from the products. In addition, the use of SC-CO2 as a reaction media has also been proposed to eliminate the inhibition limitations that encounter biodiesel production reaction using immobilized enzyme as a catalyst. Furthermore, using SC-CO2 allows easy separation of the product. In this paper, conventional biodiesel production with first generation feedstock, using chemical catalysts and solvent-extraction, is compared to new technologies with an emphasis on using microalgae, immobilized lipase, and SC-CO2 as an extraction solvent and reaction media. PMID:21915372

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…

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...

Effects of monoacylglycerols on low-temperature viscosity and cold filter plugging point of biodiesel

USDA-ARS?s Scientific Manuscript database

Biodiesel is composed of mono-alkyl fatty acid esters made from the transesterification of vegetable oil or animal fat with methanol or ethanol. Biodiesel must meet rigorous standard fuel specifications (ASTM D 6751; CEN EN 14214) to be classified as an alternative fuel. Nevertheless, biodiesel that...

Preparation of fatty acid methyl esters from Osage orange (Maclura pomifera) oil and evaluation as biodiesel

USDA-ARS?s Scientific Manuscript database

Fatty acid methyl esters were prepared in high yield by transesterification of Osage orange (Maclura pomifera) oil. Extracted using supercritical CO2, the crude oil was initially treated with mineral acid and methanol to lower its content of free fatty acids, thus rendering it amenable to homogeneou...

Preparation and characterization of the nanocomposites from chemically modified nanocellulose and poly(lactic acid)

Treesearch

Liqing Wei; Shupin Luo; Armando G. McDonald; Umesh P. Agarwal; Kolby C. Hirth; Laurent M. Matuana; Ronald C. Sabo; Nicole M. Stark

2017-01-01

Cellulose nanocrystals (CNCs) are renewable and sustainable filler for polymeric nanocomposites. However, their high hydrophilicity limits their use with hydrophobic polymer for composite materials. In this study, freeze-dried CNCs were modified by transesterification with canola oil fatty acid methyl ester to reduce the hydrophilicity. The transesterified CNCs (CNCFE...

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…

A Teaching Laboratory for Comprehensive Lipid Characterization from Food Samples

ERIC Educational Resources Information Center

Bendinskas, Kestutis; Weber, Benjamin; Nsouli, Tamara; Nguyen, Hoangvy V.; Joyce, Carolyn; Niri, Vadoud; Jaskolla, Thorsten W.

2014-01-01

Traditional and state-of-the-art techniques were combined to probe for various lipid classes from egg yolk and avocado qualitatively and quantitatively. A total lipid extract was isolated using liquid-liquid extraction. An aliquot of the total lipid extract was subjected to transesterification to form volatile fatty acid methyl esters suitable for…

Preparation of Oil of Wintergreen from Commercial Aspirin Tablets: A Microscale Experiment Highlighting Acyl Substitutions

ERIC Educational Resources Information Center

Hartel, Aaron M.; Hanna, James M., Jr.

2009-01-01

A single-pot procedure for the preparation of methyl salicylate (oil of wintergreen) from commercial aspirin tablets has been developed. The synthesis proceeds via a tandem transesterification-Fischer esterification using acidic methanol and can be carried out using either conventional or microwave heating. The experiment helps demonstrate acyl…

Utilization of waste crab shell (Scylla serrata) as a catalyst in palm olein transesterification.

PubMed

Boey, Peng-Lim; Maniam, Gaanty Pragas; Hamid, Shafida Abd

2009-01-01

Aquaculture activity has increased the population of crab, hence increasing the generation of related wastes, particularly the shell. In addition, the number of molting process in crabs compounds further the amount of waste shell generated. As such, in the present work, the application of the waste crab shell as a source of CaO in transesterification of palm olein to biodiesel (methyl ester) was investigated. Preliminary XRD results revealed that thermally activated crab shell contains mainly CaO. Parametric study has been investigated and optimal conditions were found to be methanol/oil mass ratio, 0.5:1; catalyst amount, 4 wt. %; and reaction temperature, 338 K. As compared to laboratory CaO, the catalyst from waste crab shell performs well, thus creating another low-cost catalyst source for producing biodiesel as well as adding value to the waste crab shell. Reusability of crab shell CaO has also been studied and the outcome confirmed that the catalyst is capable to be reutilized up to 11 times, without any major deterioration.

Biodiesel fuel production from waste cooking oil by the inclusion complex of heteropoly acid with bridged bis-cyclodextrin.

PubMed

Zou, Changjun; Zhao, Pinwen; Shi, Lihong; Huang, Shaobing; Luo, Pingya

2013-10-01

The inclusion complex of Cs2.5H0.5PW12O40 with bridged bis-cyclodextrin (CsPW/B) is prepared as a highly efficient catalyst for the direct production of biodiesel via the transesterification of waste cooking oil. CsPW/B is characterized by X-ray diffraction, and the biodiesel is analyzed by Gas Chromatography-Mass Spectrometer. The conversion rate of waste cooking oil is up to 94.2% under the optimum experimental conditions that are methanol/oil molar ratio of 9:1, catalyst dosage of 3 wt%, temperature of 65 °C and reaction time of 180 min. The physical properties of biodiesel sample satisfy the requirement of ASTM D6751 standards. The novel CsPW/B catalyst used for the transesterification can lead to 96.9% fatty acid methyl esters and 86.5% of the biodiesel product can serve as the ideal substitute for diesel fuel, indicating its excellent potential application in biodiesel production. Copyright © 2013 Elsevier Ltd. All rights reserved.

Waste cooking oil as source for renewable fuel in Romania

NASA Astrophysics Data System (ADS)

Allah, F. Um Min; Alexandru, G.

2016-08-01

Biodiesel is non-toxic renewable fuel which has the potential to replace diesel fuel with little or no modifications in diesel engine. Waste cooking oil can be used as source to produce biodiesel. It has environmental and economic advantages over other alternative fuels. Biodiesel production from transesterification is affected by water content, type f alcohol, catalyst type and concentration, alcohol to oil ratio, temperature, reaction rate, pH, free fatty acid (FFA) and stirrer speed. These parameters and their effect on transesterification are discussed in this paper. Properties of biodiesel obtained from waste cooking oil are measured according to local standards by distributor and their comparison with European biodiesel standard is also given in this paper. Comparison has shown that these properties lie within the limits of the EN 14214 standard. Furthermore emission performance of diesel engine for biodiesel-diesel blends has resulted in reduction of greenhouse gas emissions. Romanian fuel market can ensure energy security by mixing fuel share with biodiesel produced from waste cooking oil. Life cycle assessment of biodiesel produced from waste cooking oil has shown its viability economically and environmentally.

Enhancing Biodiesel from Kemiri Sunan Oil Manufacturing using Ultrasonics

NASA Astrophysics Data System (ADS)

Supriyadi, Slamet; Purwanto; Anggoro, Didi Dwi; Hermawan

2018-02-01

Kemiri Sunan (Reutalis trisperma (Blanco) Airy Shaw) is a potential plant to be developed as biodiesel feedstock. The advantage of Kemiri Sunan seeds when compared to other biodiesel raw materials is their high oil content. This plant is also very good for land conservation. Due the increasingly demand for biodiesel, research and new methods to increase its biodiesel production continue to be undertaken. The weakness of conventional biodiesel manufacturing process is in the mixing process in which mechanical stirring and heating in the trans-esterification process require more energy and a longer time. A higher and stronger mixing process is required to increase the contact area between the two phases of the mixed substance to produce the emulsion. Ultrasonic is a tool that can be useful for a liquid mixing process that tends to be separated. Ultrasonic waves can cause mixing intensity at the micro level and increase mass transfer, so the reaction can be performed at a much faster rate. This study is to figure out the effect of ultrasonic irradiation on the transesterification process of biodiesel from Kemiri Sunan Oil.

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.

Transesterification of sago starch and waste palm cooking oil in densified CO2

NASA Astrophysics Data System (ADS)

Muljana, H.; Sugih, A. K.; Christina, N.; Fangdinata, K.; Renaldo, J.; Rudy; Heeres, H. J.; Picchioni, F.

2017-07-01

In this work, the synthesis of biodegradable and yet renewable thermoplastics materials through a transesterification reaction of sago starch and waste palm cooking oil (WPO) in densified CO2 as the solvent is reported. The aim of this research is to investigate the potential used of sago starch and WPO as raw materials in the thermoplastics starch synthesis. The starch esters was successfully synthesized using sago starch and WPO as reagent in densified CO2 as shown from the presence of carbonyl group (C=O, 1743 cm-1) in the FT-IR spectra coupled with the presence of the proton (1H-NMR) of the fatty acid in the starch backbone (0.8 - 2 ppm). The product crystallinity decreases as shown in XRD results and resulting with a change in the thermal properties (melting and crystalline temperature) of the products. In addition, the products show a different granular morphology and a higher hydrophobicity compared with native sago starch. This research shows the potential used of sago starch and WPO in the thermoplastics starch synthesis and opens a new perspective on the product application.

Biosynthesis, characterization and enzymatic transesterification of single cell oil of Mucor circinelloides--a sustainable pathway for biofuel production.

PubMed

Carvalho, Ana K F; Rivaldi, Juan D; Barbosa, Jayne C; de Castro, Heizir F

2015-04-01

The filamentous fungus Mucor circinelloides URM 4182 was tested to determine its ability to produce single-cell oil suitable for obtaining biodiesel. Cell growth and lipid accumulation were investigated in a medium containing glucose as the main carbon source. A microwave-assisted ethanol extraction technique (microwave power ⩽200 W, 50-60 °C) was established and applied to lipid extraction from the fungal hyphae to obtain high lipid concentration (44%wt) of the dry biomass, which was considerably higher than the quantity obtained by classical solvent methods. The lipid profile showed a considerable amount of oleic acid (39.3%wt), palmitic acid (22.2%wt) and γ-linoleic acid (10.8%wt). Biodiesel was produced by transesterification of the single-cell oil with ethanol using a immobilized lipase from Candida antarctica (Novozym® 435) as the catalyst. (1)H NMR and HPLC analyses confirmed conversion of 93% of the single-cell oil from M. circinelloides into ethyl esters (FAEE). Copyright © 2015 Elsevier Ltd. All rights reserved.

Selective preparation of zeolite X and A from flyash and its use as catalyst for biodiesel production.

PubMed

Volli, Vikranth; Purkait, M K

2015-10-30

This work discusses the utilization of flyash for synthesis of heterogeneous catalyst for transesterification. Different types of zeolites were synthesized from alkali fusion followed by hydrothermal treatment of coal flyash as source material. The synthesis conditions were optimized to obtain highly crystalline zeolite based on degree of crystallinity and cation exchange capacity (CEC). The effect of CEC, acid treatment, Si/Al ratio and calcination temperature (800, 900 and 1000 °C) on zeolite formation was also studied. Pure, single phase and highly crystalline zeolite was obtained at flyash/NaOH ratio (1:1.2), fusion temperature (550 °C), fusion time (1 h), hydrothermal temperature (110 °C) and hydrothermal time (12h). The synthesized zeolite was ion-exchanged with potassium and was used as catalyst for transesterification of mustard oil to obtain a maximum conversion of 84.6% with 5 wt% catalyst concentration, 12:1 methanol to oil molar ratio, reaction time of 7 h at 65 °C. The catalyst was reused for 3 times with marginal reduction in activity. Copyright © 2015 Elsevier B.V. All rights reserved.

Improved biomass and lipid production in Synechocystis sp. NN using industrial wastes and nano-catalyst coupled transesterification for biodiesel production.

PubMed

Jawaharraj, Kalimuthu; Karpagam, Rathinasamy; Ashokkumar, Balasubramaniem; Kathiresan, Shanmugam; Moorthy, Innasi Muthu Ganesh; Arumugam, Muthu; Varalakshmi, Perumal

2017-10-01

In this study, the improved biomass (1.6 folds) and lipid (1.3 folds) productivities in Synechocystis sp. NN using agro-industrial wastes supplementation through hybrid response surface methodology-genetic algorithm (RSM-GA) for cost-effective methodologies for biodiesel production was achieved. Besides, efficient harvesting in Synechocystis sp. NN was achieved by electroflocculation (flocculation efficiency 97.8±1.2%) in 10min when compared to other methods. Furthermore, different pretreatment methods were employed for lipid extraction and maximum lipid content of 19.3±0.2% by Synechocystis sp. NN was attained by ultrasonication than microwave and liquid nitrogen assisted pretreatment methods. The highest FAME (fatty acid methyl ester) conversion of 36.5±8.3mg FAME/g biomass was obtained using titanium oxide as heterogeneous nano-catalyst coupled whole-cell transesterification based method. Conclusively, Synechocystis sp. NN may be used as a biodiesel feedstock and its fuel production can be enriched by hybrid RSM-GA and nano-catalyst technologies. Copyright © 2017 Elsevier Ltd. All rights reserved.

Glymes as benign co-solvents for CaO-catalyzed transesterification of soybean oil to biodiesel.

PubMed

Tang, Shaokun; Zhao, Hua; Song, Zhiyan; Olubajo, Olarongbe

2013-07-01

The base (such as CaO)-catalyzed heterogeneous preparation of biodiesel encounters a number of obstacles including the need for CaO pretreatment and the reactions being incomplete (typically 90-95% yields). In this study, a number of glymes were investigated as benign solvents for the CaO-catalyzed transesterification of soybean oil into biodiesel with a high substrate loading (typically soybean oil >50% v/v). The triglyceride-dissolving capability of glymes led to a much faster reaction rate (>98% conversions in 4h) than in methanol alone (typically 24h) and minimized the saponification reaction when catalyzed by anhydrous CaO or commercial lime without pre-activation. The use of glyme (e.g. P2) as co-solvent also activates commercial lime to become an effective catalyst without calcination pretreatment. The SEM images suggest a dissolution-agglomeration process of CaO surface in the presence of P2, which could remove the CaCO3 and Ca(OH)2 layer coated on the surface of lime. Copyright © 2013 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.

Enantiomeric separation of pharmaceutically important drug intermediates using a Metagenomic lipase and optimization of its large scale production.

PubMed

Kumar, Rakesh; Banoth, Linga; Banerjee, Uttam Chand; Kaur, Jagdeep

2017-02-01

In the present study, efficient enzymatic methods were developed using a recombinant metagenomic lipase (LipR1) for the synthesis of corresponding esters by the transesterification of five different pharmaceutically important secondary alcohols. The recombinant lipase (specific activity=87m6U/mg) showed maximum conversion in presence of ionic liquid with Naphthyl-ethanol (eeP=99%), Indanol and Methyl-4 pyridine methanol (eeS of 98% and 99%) respectively in 1h. Vinyl acetate was found as suitable acyl donor in transesterification reactions. It was interesting to observe that maximum eeP of 85% was observed in just 15min with 1-indanol. As this enzyme demonstrated pharmaceutical applications, attempts were made to scale up the enzyme production on a pilot scale in a 5litre bioreactor. Different physical parameters affecting enzyme production and biomass concentration such as agitation rate, aeration rate and inoculum concentration were evaluated. Maximum lipase activity of 8463U/ml was obtained at 7h of cultivation at 1 lpm, 300rpm and 1.5% inoculum. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

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.

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.

Genetic Interaction Mapping in Schizosaccharomyces pombe Using the Pombe Epistasis Mapper (PEM) System and a ROTOR HDA Colony Replicating Robot in a 1536 Array Format.

PubMed

Roguev, Assen; Xu, Jiewei; Krogan, Nevan

2018-02-01

This protocol describes an optimized high-throughput procedure for generating double deletion mutants in Schizosaccharomyces pombe using the colony replicating robot ROTOR HDA and the PEM (pombe epistasis mapper) system. The method is based on generating high-density colony arrays (1536 colonies per agar plate) and passaging them through a series of antidiploid and mating-type selection (ADS-MTS) and double-mutant selection (DMS) steps. Detailed program parameters for each individual replication step are provided. Using this procedure, batches of 25 or more screens can be routinely performed. © 2018 Cold Spring Harbor Laboratory Press.

Coupling Admissions and Curricular Data to Predict Medical Student Outcomes

ERIC Educational Resources Information Center

Sesate, Diana B.; Milem, Jeffrey F.; McIntosh, Kadian L.; Bryan, W. Patrick

2017-01-01

The relative impact of admissions factors and curricular measures on the first medical licensing exam (United States Medical Licensing Exam [USMLE] Step 1) scores is examined. The inclusion of first-year and second-year curricular measures nearly doubled the variance explained in Step 1 scores from the amount explained by the combination of…

DNA purification by triplex-affinity capture and affinity capture electrophoresis

DOEpatents

Cantor, Charles R.; Ito, Takashi; Smith, Cassandra L.

1996-01-01

The invention provides a method for purifying or isolating double stranded DNA intact using triple helix formation. The method includes the steps of complexing an oligonucleotide and double stranded DNA to generate a triple helix and immobilization of the triple helix on a solid phase by means of a molecular recognition system such as avidin/biotin. The purified DNA is then recovered intact by treating the solid phase with a reagent that breaks the bonds between the oligonucleotide and the intact double stranded DNA while not affecting the Watson-Crick base pairs of the double helix. The present invention also provides a method for purifying or isolating double stranded DNA intact by complexing the double stranded DNA with a specific binding partner and recovering the complex during electrophoresis by immobilizing it on a solid phase trap imbedded in an electrophoretic gel.

Kinetics of acyl transfer reactions in organic media catalysed by Candida antarctica lipase B.

PubMed

Martinelle, M; Hult, K

1995-09-06

The acyl transfer reactions catalysed by Candida antartica lipase B in organic media followed a bi-bi ping-pong mechanism, with competitive substrate inhibition by the alcohols used as acyl acceptors. The effect of organic solvents on Vm and Km was investigated. The Vm values in acetonitrile was 40-50% of those in heptane. High Km values in acetonitrile compared to those in heptane could partly be explained by an increased solvation of the substrates in acetonitrile. Substrate solvation caused a 10-fold change in substrate specificity, defined as (Vm/Km)ethyl octanoate/(Vm/Km)octanoic acid, going from heptane to acetonitrile. Deacylation was the rate determining step for the acyl transfer in heptane with vinyl- and ethyl octanoate as acyl donors and (R)-2-octanol as acyl acceptor. With 1-octanol, a rate determining deacylation step in heptane was indicated using the same acyl donors. Using 1-octanol as acceptor in heptane, S-ethyl thiooctanoate had a 25- to 30-fold lower Vm/Km value and vinyl octanoate a 4-fold higher Vm/Km value than that for ethyl octanoate. The difference showed to be a Km effect for vinyl octanoate and mainly a Km effect for S-ethyl thiooctanoate. The Vm values of the esterification of octanoic acid with different alcohols was 10-30-times lower than those for the corresponding transesterification of ethyl octanoate. The low activity could be explained by a low pH around the enzyme caused by the acid or a withdrawing of active enzyme by nonproductive binding by the acid.

The oscillatory behavior of the CoM facilitates mechanical energy balance between push-off and heel strike.

PubMed

Kim, Seyoung; Park, Sukyung

2012-01-10

Humans use equal push-off and heel strike work during the double support phase to minimize the mechanical work done on the center of mass (CoM) during the gait. Recently, a step-to-step transition was reported to occur over a period of time greater than that of the double support phase, which brings into question whether the energetic optimality is sensitive to the definition of the step-to-step transition. To answer this question, the ground reaction forces (GRFs) of seven normal human subjects walking at four different speeds (1.1-2.4 m/s) were measured, and the push-off and heel strike work for three differently defined step-to-step transitions were computed based on the force, work, and velocity. To examine the optimality of the work and the impulse data, a hybrid theoretical-empirical analysis is presented using a dynamic walking model that allows finite time for step-to-step transitions and incorporates the effects of gravity within this period. The changes in the work and impulse were examined parametrically across a range of speeds. The results showed that the push-off work on the CoM was well balanced by the heel strike work for all three definitions of the step-to-step transition. The impulse data were well matched by the optimal impulse predictions (R(2)>0.7) that minimized the mechanical work done on the CoM during the gait. The results suggest that the balance of push-off and heel strike energy is a consistent property arising from the overall gait dynamics, which implies an inherited oscillatory behavior of the CoM, possibly by spring-like leg mechanics. Copyright © 2011 Elsevier Ltd. All rights reserved.

Absence of equifinality of hand position in a double-step unloading task.

PubMed

Norouzi-Gheidari, Nahid; Archambault, Philippe

2010-08-01

Equifinality, during arm reaching movements, relates to the capacity of the neuromuscular system to attain the same final position in the presence or absence of transient perturbations. There have been several controversies regarding equifinality in the literature. A brief elastic perturbation, applied during a fast arm movement or just before its initiation, typically does not affect final arm position. On the other hand, several experiments have shown that velocity-dependent perturbations, such as Coriolis force or negative damping, while transient in nature, have a significant effect on final arm position when compared to unperturbed movements. In this study, an unloading paradigm was used to study the role of reflexes with respect to equifinality. The effects on final arm position of suddenly decreasing a static load maintained by fourteen subjects were analyzed. Subjects maintained an initial load produced by a double-joint manipulandum moving in the horizontal plane. The load was suddenly decreased, either in one or in two successive steps with different time intervals, resulting in a rapid reflex-mediated change in arm position. Unloading led to short-latency changes in the activity of shoulder and elbow muscles and significant variations in tonic activity. It was found that the final hand position was shorter for double- versus single-step unloading if the time between two successive changes in load was greater than 100 ms. With a shorter time interval, the final hand positions were the same. This difference in final hand positions was inversely proportional to the hand velocity at the time of the second change in load. Further, agonist/antagonist co-activation increased in double-step unloading. Thus, the change in both the load and the movement velocity may influence the magnitude of the unloading reflex. This may be indicative of a dependence of stretch reflexes on velocity. Perturbation may cause a reflex-mediated increase in joint stiffness, which could explain why equifinality is not preserved after some perturbations, such as velocity-dependant external forces.

A Comparative Evaluation of the Linear Dimensional Accuracy of Four Impression Techniques using Polyether Impression Material.

PubMed

Manoj, Smita Sara; Cherian, K P; Chitre, Vidya; Aras, Meena

2013-12-01

There is much discussion in the dental literature regarding the superiority of one impression technique over the other using addition silicone impression material. However, there is inadequate information available on the accuracy of different impression techniques using polyether. The purpose of this study was to assess the linear dimensional accuracy of four impression techniques using polyether on a laboratory model that simulates clinical practice. The impression material used was Impregum Soft™, 3 M ESPE and the four impression techniques used were (1) Monophase impression technique using medium body impression material. (2) One step double mix impression technique using heavy body and light body impression materials simultaneously. (3) Two step double mix impression technique using a cellophane spacer (heavy body material used as a preliminary impression to create a wash space with a cellophane spacer, followed by the use of light body material). (4) Matrix impression using a matrix of polyether occlusal registration material. The matrix is loaded with heavy body material followed by a pick-up impression in medium body material. For each technique, thirty impressions were made of a stainless steel master model that contained three complete crown abutment preparations, which were used as the positive control. Accuracy was assessed by measuring eight dimensions (mesiodistal, faciolingual and inter-abutment) on stone dies poured from impressions of the master model. A two-tailed t test was carried out to test the significance in difference of the distances between the master model and the stone models. One way analysis of variance (ANOVA) was used for multiple group comparison followed by the Bonferroni's test for pair wise comparison. The accuracy was tested at α = 0.05. In general, polyether impression material produced stone dies that were smaller except for the dies produced from the one step double mix impression technique. The ANOVA revealed a highly significant difference for each dimension measured (except for the inter-abutment distance between the first and the second die) between any two groups of stone models obtained from the four impression techniques. Pair wise comparison for each measurement did not reveal any significant difference (except for the faciolingual distance of the third die) between the casts produced using the two step double mix impression technique and the matrix impression system. The two step double mix impression technique produced stone dies that showed the least dimensional variation. During fabrication of a cast restoration, laboratory procedures should not only compensate for the cement thickness, but also for the increase or decrease in die dimensions.

1,3-Diferuloyl-sn-glycerol from the biocatalytic transesterification of ethyl 4-hydroxy-3-methoxy cinnamic acid (ethyl ferulate) and soybean oil

USDA-ARS?s Scientific Manuscript database

1,3-Diferuloyl-sn-glycerol is a natural plant component found ubiquitously throughout the plant kingdom, possessing ultraviolet adsorbing and antioxidant properties. Diferuloyl glycerol was synthesized and isolated as a byproduct in up to 5% yield from the pilot plant scale packed-bed, biocatalytic...

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…

Determination of the Heat of Combustion of Biodiesel Using Bomb Calorimetry: A Multidisciplinary Undergraduate Chemistry Experiment

ERIC Educational Resources Information Center

Akers, Stephen M.; Conkle, Jeremy L.; Thomas, Stephanie N.; Rider, Keith B.

2006-01-01

Biodiesel was synthesized by transesterification of waste vegetable oil using common glassware and reagents, and characterized by measuring heat of combustion, cloud point, density and measuring the heat of combustion and density together allows the student the energy density of the fuel. Analyzing the biodiesel can serve as a challenging and…

Studies on the InAlN/InGaN/InAlN/InGaN double channel heterostructures with low sheet resistance

NASA Astrophysics Data System (ADS)

Zhang, Yachao; Wang, Zhizhe; Xu, Shengrui; Chen, Dazheng; Bao, Weimin; Zhang, Jinfeng; Zhang, Jincheng; Hao, Yue

2017-11-01

High quality InAlN/InGaN/InAlN/InGaN double channel heterostructures were proposed and grown by metal organic chemical vapor deposition. Benefiting from the adoption of the pulsed growth method and Two-Step AlN interlayer, the material quality and interface characteristics of the double channel heterostructures are satisfactory. The results of the temperature-dependent Hall effect measurement indicated that the transport properties of the double channel heterostructures were superior to those of the traditional single channel heterostructures in the whole test temperature range. Meanwhile, the sheet resistance of the double channel heterostructures reached 218.5 Ω/□ at 300 K, which is the record of InGaN-based heterostructures. The good transport properties of the InGaN double channel heterostructures are beneficial to improve the performance of the microwave power devices based on nitride semiconductors.

Self-assembly of a double-helical complex of sodium.

PubMed

Bell, T W; Jousselin, H

1994-02-03

Spontaneous self-organization of helical and multiple-helical molecular structures occurs on several levels in living organisms. Key examples are alpha-helical polypeptides, double-helical nucleic acids and helical protein structures, including F-actin, microtubules and the protein sheath of the tobacco mosaic virus. Although the self-assembly of double-helical transition-metal complexes bears some resemblance to the molecular organization of double-stranded DNA, selection between monohelical, double-helical and triple-helical structures is determined largely by the size and geometrical preference of the tightly bound metal. Here we present an example of double-helical assembly induced by the weaker and non-directional interactions of an alkali-metal ion with an organic ligand that is pre-organized into a coil. We have characterized the resulting complex by two-dimensional NMR and fast-atom-bombardment mass spectrometry. These results provide a step toward the creation of molecular tubes or ion channels consisting of intertwined coils.

DNA purification by triplex-affinity capture and affinity capture electrophoresis

DOEpatents

Cantor, C.R.; Ito, Takashi; Smith, C.L.

1996-01-09

The invention provides a method for purifying or isolating double stranded DNA intact using triple helix formation. The method includes the steps of complexing an oligonucleotide and double stranded DNA to generate a triple helix and immobilization of the triple helix on a solid phase by means of a molecular recognition system such as avidin/biotin. The purified DNA is then recovered intact by treating the solid phase with a reagent that breaks the bonds between the oligonucleotide and the intact double stranded DNA while not affecting the Watson-Crick base pairs of the double helix. The present invention also provides a method for purifying or isolating double stranded DNA intact by complexing the double stranded DNA with a specific binding partner and recovering the complex during electrophoresis by immobilizing it on a solid phase trap imbedded in an electrophoretic gel. 6 figs.

Palladium-catalyzed double carbonylation using near stoichiometric carbon monoxide: expedient access to substituted 13C2-labeled phenethylamines.

PubMed

Nielsen, Dennis U; Neumann, Karoline; Taaning, Rolf H; Lindhardt, Anders T; Modvig, Amalie; Skrydstrup, Troels

2012-07-20

A novel and general approach for (13)C(2)- and (2)H-labeled phenethylamine derivatives has been developed, based on a highly convergent single-step assembly of the carbon skeleton. The efficient incorporation of two carbon-13 isotopes into phenethylamines was accomplished using a palladium-catalyzed double carbonylation of aryl iodides with near stoichiometric carbon monoxide.

[Simultaneous double prosthesis implant more artificial urinary sphincter via transscrotal: surgical technique].

PubMed

Martínez-Salamanca, Juan Ignacio; Moncada, Ignacio; del Portillo, Luis; Sola, Ignacio; Martínez-Ballesteros, Claudio; Carballido, Joaquín

2011-04-01

Moderate-severe urinary incontinence and refractory-to-treatment erectile dysfunction after radical prostatectomy are two entities causing an important loss of quality of life to patients. The double implant of penile prosthesis and artificial urinary sphincter is a safe and effective option in these cases. This article describes preoperative considerations and the most important technical steps to do it satisfactorily.

Linear-scaling generation of potential energy surfaces using a double incremental expansion

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

König, Carolin, E-mail: carolink@kth.se; Christiansen, Ove, E-mail: ove@chem.au.dk

We present a combination of the incremental expansion of potential energy surfaces (PESs), known as n-mode expansion, with the incremental evaluation of the electronic energy in a many-body approach. The application of semi-local coordinates in this context allows the generation of PESs in a very cost-efficient way. For this, we employ the recently introduced flexible adaptation of local coordinates of nuclei (FALCON) coordinates. By introducing an additional transformation step, concerning only a fraction of the vibrational degrees of freedom, we can achieve linear scaling of the accumulated cost of the single point calculations required in the PES generation. Numerical examplesmore » of these double incremental approaches for oligo-phenyl examples show fast convergence with respect to the maximum number of simultaneously treated fragments and only a modest error introduced by the additional transformation step. The approach, presented here, represents a major step towards the applicability of vibrational wave function methods to sizable, covalently bound systems.« less

Attosecond twin-pulse control by generalized kinetic heterodyne mixing.

PubMed

Raith, Philipp; Ott, Christian; Pfeifer, Thomas

2011-01-15

Attosecond double-pulse (twin-pulse) production in high-order harmonic generation is manipulated by a combination of two-color and carrier-envelope phase-control methods. As we show in numerical simulations, both relative amplitude and phase of the double pulse can be independently set by making use of multidimensional parameter control. Two technical implementation routes are discussed: kinetic heterodyning using second-harmonic generation and split-spectrum phase-step control.

Impact of SCBA size and fatigue from different firefighting work cycles on firefighter gait.

PubMed

Kesler, Richard M; Bradley, Faith F; Deetjen, Grace S; Angelini, Michael J; Petrucci, Matthew N; Rosengren, Karl S; Horn, Gavin P; Hsiao-Wecksler, Elizabeth T

2018-04-04

Risk of slips, trips and falls in firefighters maybe influenced by the firefighter's equipment and duration of firefighting. This study examined the impact of a four self-contained breathing apparatus (SCBA) three SCBA of increasing size and a prototype design and three work cycles one bout (1B), two bouts with a five-minute break (2B) and two bouts back-to-back (BB) on gait in 30 firefighters. Five gait parameters (double support time, single support time, stride length, step width and stride velocity) were examined pre- and post-firefighting activity. The two largest SCBA resulted in longer double support times relative to the smallest SCBA. Multiple bouts of firefighting activity resulted in increased single and double support time and decreased stride length, step width and stride velocity. These results suggest that with larger SCBA or longer durations of activity, firefighters may adopt more conservative gait patterns to minimise fall risk. Practitioner Summary: The effects of four self-contained breathing apparatus (SCBA) and three work cycles on five gait parameters were examined pre- and post-firefighting activity. Both SCBA size and work cycle affected gait. The two largest SCBA resulted in longer double support times. Multiple bouts of activity resulted in more conservative gait patterns.

Preparation of Biofuel Using Acetylatation of Jojoba Fatty Alcohols and Assessment as a Blend Component in Ultra Low Sulfur Diesel Fuel

USDA-ARS?s Scientific Manuscript database

The majority of biodiesel fuels are produced from vegetable oils or animal fats by transesterification of oil with alcohol in the presence of a catalyst. In this study, a new class of biofuel is explored by acetylation of fatty alcohols from Jojoba oil. Recently, we reported Jojoba oil methyl este...

40 CFR 80.1426 - How are RINs generated and assigned to batches of renewable fuel by renewable fuel producers or...

Code of Federal Regulations, 2014 CFR

2014-07-01

... process energy 6 F Biodiesel, renewable diesel, jet fuel and heating oil Soy bean oil; Oil from annual... biomass and petroleum 4 G Biodiesel, heating oil Canola/Rapeseed oil Trans-Esterification using natural gas or biomass for process energy 4 H Biodiesel, renewable diesel, jet fuel and heating oil Soy bean...

40 CFR 80.1426 - How are RINs generated and assigned to batches of renewable fuel by renewable fuel producers or...

Code of Federal Regulations, 2012 CFR

2012-07-01

... Fermentation using natural gas, biomass, or biogas for process energy 6 Biodiesel, and renewable diesel Soy... renewable biomass and petroleum 4 Biodiesel Canola oil Trans-Esterification using natural gas or biomass for process energy 4 Biodiesel, and renewable diesel Soy bean oil;Oil from annual covercrops; Algal oil...

40 CFR 80.1426 - How are RINs generated and assigned to batches of renewable fuel by renewable fuel producers or...

Code of Federal Regulations, 2011 CFR

2011-07-01

... Fermentation using natural gas, biomass, or biogas for process energy 6 Biodiesel, and renewable diesel Soy... renewable biomass and petroleum 4 Biodiesel Canola oil Trans-Esterification using natural gas or biomass for process energy 4 Biodiesel, and renewable diesel Soy bean oil;Oil from annual covercrops; Algal oil...

Organic Chemistry and the Native Plants of the Sonoran Desert: Conversion of Jojoba Oil to Biodiesel

ERIC Educational Resources Information Center

Daconta, Lisa V.; Minger, Timothy; Nedelkova, Valentina; Zikopoulos, John N.

2015-01-01

A new, general approach to the organic chemistry laboratory is introduced that is based on learning about organic chemistry techniques and research methods by exploring the natural products found in local native plants. As an example of this approach for the Sonoran desert region, the extraction of jojoba oil and its transesterification to…

Production of Truncated Candida antarctica Lipase B Gene Using Automated PCR Gene Assembly Protocol and Expression in Yeast for use in Ethanol and Biodiesel Production.

USDA-ARS?s Scientific Manuscript database

An improved column-based process for production of biodiesel was developed using a column containing a strongly basic anion-exchange resin in sequence with a column containing a resin to which a lipase biocatalyst is bound. Currently most biodiesel is produced by transesterification of triglyceride...

Biodiesel From waste cooking oil for heating, lighting, or running diesel engines

Treesearch

Rico O. Cruz

2009-01-01

Biodiesel and its byproducts and blends can be used as alternative fuel in diesel engines and for heating, cooking, and lighting. A simple process of biodiesel production can utilize waste cooking oil as the main feedstock to the transesterification and cruzesterification processes. I currently make my own biodiesel for applications related to my nursery and greenhouse...

Deuterium Exchange in Ethyl Acetoacetate: An Undergraduate GC-MS [Gas Chromatography-Mass Spectroscopy] Experiment

ERIC Educational Resources Information Center

Heinson, C. D.; Williams, J. M.; Tinnerman, W. N.; Malloy, T. B.

2005-01-01

The role of ethanol O-d in nullifying the deuterolysis may be demonstrated by determining that transesterification of methyl acetoacetate of the ethyl ester occurs as well as deuterium exchange of the five acetoacetate hydrogens. The significant acidity of the methylene protons in the acetoacetate group, the efficacy of base catalysis, the role of…

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.

Biodiesel Production: Utilization of Loofah Sponge to Immobilize Rhizopus chinensis CGMCC #3.0232 Cells as a Whole-Cell Biocatalyst.

PubMed

He, Qiyang; Xia, Qianjun; Wang, Yuejiao; Li, Xun; Zhang, Yu; Hu, Bo; Wang, Fei

2016-07-28

Rhizopus chinensis cells immobilized on loofah (Luffa cylindrica) sponges were used to produce biodiesel via the transesterification of soybean oil. In whole-cell immobilization, loofah sponge is considered to be a superior alternative to conventional biomass carriers because of its biodegradable and renewable properties. During cell cultivation, Rhizopus chinensis mycelia can spontaneously and firmly adhere to the surface of loofah sponge particles. The optimal conditions for processing 9.65 g soybean oil at 40°C and 180 rpm using a 3:1 methanol-to-oil molar ratio were found to be 8% cell addition and 3-10% water content (depending on the oil's weight). Under optimal conditions, an over 90% methyl ester yield was achieved after the first reaction batch. The operational stability of immobilized Rhizopus chinensis cells was assayed utilizing a 1:1 methanol-to-oil molar ratio, thus resulting in a 16.5-fold increase in half-life when compared with immobilized cells of the widely studied Rhizopus oryzae. These results suggest that transesterification of vegetable oil using Rhizopus chinensis whole cells immobilized onto loofah sponge is an effective approach for biodiesel production.

Synthesis of biodiesel from waste cooking oil using sonochemical reactors.

PubMed

Hingu, Shishir M; Gogate, Parag R; Rathod, Virendra K

2010-06-01

Investigation into newer routes of biodiesel synthesis is a key research area especially due to the fluctuations in the conventional fuel prices and the environmental advantages of biodiesel. The present work illustrates the use of sonochemical reactors for the synthesis of biodiesel from waste cooking oil. Transesterification of used frying oil with methanol, in the presence of potassium hydroxide as a catalyst has been investigated using low frequency ultrasonic reactor (20 kHz). Effect of different operating parameters such as alcohol-oil molar ratio, catalyst concentration, temperature, power, pulse and horn position on the extent of conversion of oil have been investigated. The optimum conditions for the transesterification process have been obtained as molar ratio of alcohol to oil as 6:1, catalyst concentration of 1 wt.%, temperature as 45 degrees C and ultrasound power as 200 W with an irradiation time of 40 min. The efficacy of using ultrasound has been compared with the conventional stirring approach based on the use of a six blade turbine with diameter of 1.5 cm operating at 1000 rpm. Also the purification aspects of the final product have been investigated. (c) 2010 Elsevier B.V. All rights reserved.

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.

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.

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.

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.

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.

Gold Nanoparticles Supported on a Layered Double Hydroxide as Efficient Catalysts for the One-Pot Synthesis of Flavones.

PubMed

Yatabe, Takafumi; Jin, Xiongjie; Yamaguchi, Kazuya; Mizuno, Noritaka

2015-11-02

Flavones are a class of natural products with diverse biological activities and have frequently been synthesized by step-by-step procedures using stoichiometric amounts of reagents. Herein, a catalytic one-pot procedure for the synthesis of flavone and its derivatives is developed. In the presence of gold nanoparticles supported on a Mg-Al layered double hydroxide (Au/LDH), various kinds of flavones can be synthesized starting from 2'-hydroxyacetophenones and benzaldehydes (or benzyl alcohols). The present one-pot procedure consists of a sequence of several reactions, and Au/LDH can catalyze all these different types of reactions. The catalysis is shown to be truly heterogeneous, and Au/LDH can be readily recovered and reused. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Laboratory layered latte.

PubMed

Xue, Nan; Khodaparast, Sepideh; Zhu, Lailai; Nunes, Janine K; Kim, Hyoungsoo; Stone, Howard A

2017-12-12

Inducing thermal gradients in fluid systems with initial, well-defined density gradients results in the formation of distinct layered patterns, such as those observed in the ocean due to double-diffusive convection. In contrast, layered composite fluids are sometimes observed in confined systems of rather chaotic initial states, for example, lattes formed by pouring espresso into a glass of warm milk. Here, we report controlled experiments injecting a fluid into a miscible phase and show that, above a critical injection velocity, layering emerges over a time scale of minutes. We identify critical conditions to produce the layering, and relate the results quantitatively to double-diffusive convection. Based on this understanding, we show how to employ this single-step process to produce layered structures in soft materials, where the local elastic properties vary step-wise along the length of the material.

Interactions of double patterning technology with wafer processing, OPC and design flows

NASA Astrophysics Data System (ADS)

Lucas, Kevin; Cork, Chris; Miloslavsky, Alex; Luk-Pat, Gerry; Barnes, Levi; Hapli, John; Lewellen, John; Rollins, Greg; Wiaux, Vincent; Verhaegen, Staf

2008-03-01

Double patterning technology (DPT) is one of the main options for printing logic devices with half-pitch less than 45nm; and flash and DRAM memory devices with half-pitch less than 40nm. DPT methods decompose the original design intent into two individual masking layers which are each patterned using single exposures and existing 193nm lithography tools. The results of the individual patterning layers combine to re-create the design intent pattern on the wafer. In this paper we study interactions of DPT with lithography, masks synthesis and physical design flows. Double exposure and etch patterning steps create complexity for both process and design flows. DPT decomposition is a critical software step which will be performed in physical design and also in mask synthesis. Decomposition includes cutting (splitting) of original design intent polygons into multiple polygons where required; and coloring of the resulting polygons. We evaluate the ability to meet key physical design goals such as: reduce circuit area; minimize rework; ensure DPT compliance; guarantee patterning robustness on individual layer targets; ensure symmetric wafer results; and create uniform wafer density for the individual patterning layers.

Gait parameter control timing with dynamic manual contact or visual cues

PubMed Central

Shi, Peter; Werner, William

2016-01-01

We investigated the timing of gait parameter changes (stride length, peak toe velocity, and double-, single-support, and complete step duration) to control gait speed. Eleven healthy participants adjusted their gait speed on a treadmill to maintain a constant distance between them and a fore-aft oscillating cue (a place on a conveyor belt surface). The experimental design balanced conditions of cue modality (vision: eyes-open; manual contact: eyes-closed while touching the cue); treadmill speed (0.2, 0.4, 0.85, and 1.3 m/s); and cue motion (none, ±10 cm at 0.09, 0.11, and 0.18 Hz). Correlation analyses revealed a number of temporal relationships between gait parameters and cue speed. The results suggest that neural control ranged from feedforward to feedback. Specifically, step length preceded cue velocity during double-support duration suggesting anticipatory control. Peak toe velocity nearly coincided with its most-correlated cue velocity during single-support duration. The toe-off concluding step and double-support durations followed their most-correlated cue velocity, suggesting feedback control. Cue-tracking accuracy and cue velocity correlations with timing parameters were higher with the manual contact cue than visual cue. The cue/gait timing relationships generalized across cue modalities, albeit with greater delays of step-cycle events relative to manual contact cue velocity. We conclude that individual kinematic parameters of gait are controlled to achieve a desired velocity at different specific times during the gait cycle. The overall timing pattern of instantaneous cue velocities associated with different gait parameters is conserved across cues that afford different performance accuracies. This timing pattern may be temporally shifted to optimize control. Different cue/gait parameter latencies in our nonadaptation paradigm provide general-case evidence of the independent control of gait parameters previously demonstrated in gait adaptation paradigms. PMID:26936979

Double-Vacuum-Bag Process for Making Resin-Matrix Composites

NASA Technical Reports Server (NTRS)

Bradford, Larry J.

2007-01-01

A double-vacuum-bag process has been devised as a superior alternative to a single-vacuum-bag process used heretofore in making laminated fiber-reinforced resin-matrix composite-material structural components. This process is applicable to broad classes of high-performance matrix resins including polyimides and phenolics that emit volatile compounds (solvents and volatile by-products of resin-curing chemical reactions) during processing. The superiority of the double-vacuum-bag process lies in enhanced management of the volatile compounds. Proper management of volatiles is necessary for making composite-material components of high quality: if not removed and otherwise properly managed, volatiles can accumulate in interior pockets as resins cure, thereby forming undesired voids in the finished products. The curing cycle for manufacturing a composite laminate containing a reactive resin matrix usually consists of a two-step ramp-and-hold temperature profile and an associated single-step pressure profile as shown in Figure 1. The lower-temperature ramp-and-hold step is known in the art as the B stage. During the B stage, prepregs are heated and volatiles are generated. Because pressure is not applied at this stage, volatiles are free to escape. Pressure is applied during the higher-temperature ramp-and-hold step to consolidate the laminate and impart desired physical properties to the resin matrix. The residual volatile content and fluidity of the resin at the beginning of application of consolidation pressure are determined by the temperature and time parameters of the B stage. Once the consolidation pressure is applied, residual volatiles are locked in. In order to produce a void-free, high-quality laminate, it is necessary to design the curing cycle to obtain the required residual fluidity and the required temperature at the time of application of the consolidation pressure.

Efficient and simpler method to construct normalized cDNA libraries with improved representations of full-length cDNAs

DOEpatents

Soares, Marcelo Bento; Bonaldo, Maria de Fatima

1998-01-01

This invention provides a method to normalize a cDNA library comprising: (a) constructing a directionally cloned library containing cDNA inserts wherein the insert is capable of being amplified by polymerase chain reaction; (b) converting a double-stranded cDNA library into single-stranded DNA circles; (c) generating single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) by polymerase chain reaction with appropriate primers; (d) hybridizing the single-stranded DNA circles converted in step (b) with the complementary single-stranded nucleic acid molecules generated in step (c) to produce partial duplexes to an appropriate Cot; and (e) separating the unhybridized single-stranded DNA circles from the hybridized DNA circles, thereby generating a normalized cDNA library. This invention also provides a method to normalize a cDNA library wherein the generating of single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) is by excising cDNA inserts from the double-stranded cDNA library; purifying the cDNA inserts from cloning vectors; and digesting the cDNA inserts with an exonuclease. This invention further provides a method to construct a subtractive cDNA library following the steps described above. This invention further provides normalized and/or subtractive cDNA libraries generated by the above methods.

Efficient and simpler method to construct normalized cDNA libraries with improved representations of full-length cDNAs

DOEpatents

Soares, M.B.; Fatima Bonaldo, M. de

1998-12-08

This invention provides a method to normalize a cDNA library comprising: (a) constructing a directionally cloned library containing cDNA inserts wherein the insert is capable of being amplified by polymerase chain reaction; (b) converting a double-stranded cDNA library into single-stranded DNA circles; (c) generating single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) by polymerase chain reaction with appropriate primers; (d) hybridizing the single-stranded DNA circles converted in step (b) with the complementary single-stranded nucleic acid molecules generated in step (c) to produce partial duplexes to an appropriate Cot; and (e) separating the unhybridized single-stranded DNA circles from the hybridized DNA circles, thereby generating a normalized cDNA library. This invention also provides a method to normalize a cDNA library wherein the generating of single-stranded nucleic acid molecules complementary to the single-stranded DNA circles converted in step (b) is by excising cDNA inserts from the double-stranded cDNA library; purifying the cDNA inserts from cloning vectors; and digesting the cDNA inserts with an exonuclease. This invention further provides a method to construct a subtractive cDNA library following the steps described above. This invention further provides normalized and/or subtractive cDNA libraries generated by the above methods. 25 figs.

Development of Turbulence Models for Shear Flows by a Double Expansion technique.

DTIC Science & Technology

1991-07-01

Let us introduce the dimensionless variables 7 = -; I -_o E ~ Ko where S = (2Sij Sij)112 and K0 is the initial turbulent kinetic energy. In...simulation of Bardina eta 1 4 for co/ SKo = 0.296 Figure 2 19 IlI H- L -1 y x Turbulent flow over a backward facing step Figure 3 20 BACKWARD-FACING STEP

Novel technologies in doubled haploid line development.

PubMed

Ren, Jiaojiao; Wu, Penghao; Trampe, Benjamin; Tian, Xiaolong; Lübberstedt, Thomas; Chen, Shaojiang

2017-11-01

haploid inducer line can be transferred (DH) technology can not only shorten the breeding process but also increase genetic gain. Haploid induction and subsequent genome doubling are the two main steps required for DH technology. Haploids have been generated through the culture of immature male and female gametophytes, and through inter- and intraspecific via chromosome elimination. Here, we focus on haploidization via chromosome elimination, especially the recent advances in centromere-mediated haploidization. Once haploids have been induced, genome doubling is needed to produce DH lines. This study has proposed a new strategy to improve haploid genome doubling by combing haploids and minichromosome technology. With the progress in haploid induction and genome doubling methods, DH technology can facilitate reverse breeding, cytoplasmic male sterile (CMS) line production, gene stacking and a variety of other genetic analysis. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

STM/STS Study of the Sb (111) Surface

NASA Astrophysics Data System (ADS)

Chekmazov, S. V.; Bozhko, S. I.; Smirnov, A. A.; Ionov, A. M.; Kapustin, A. A.

An Sb crystal is a Peierls insulator. Formation of double layers in the Sb structure is due to the shift of atomic planes (111) next but one along the C3 axis. Atomic layers inside the double layer are connected by covalent bonds. The interaction between double layers is determined mainly by Van der Waals forces. The cleave of an Sb single crystal used to be via break of Van der Waals bonds. However, using scanning tunneling microscopy (STM) and spectroscopy (STS) we demonstrated that apart from islands equal in thickness to the double layer, steps of one atomic layer in height also exist on the cleaved Sb (111) surface. Formation of "unpaired" (111) planes on the surface leads to a local break of conditions of Peierls transition. STS experiment reveals higher local density of states (LDOS) measured for "unpaired" (111) planes in comparison with those for the double layer.

Fast and economic immobilization methods described for non-commercial Pseudomonas lipases

PubMed Central

2014-01-01

Background There is an increasing interest to seek new enzyme preparations for the development of new products derived from bioprocesses to obtain alternative bio-based materials. In this context, four non-commercial lipases from Pseudomonas species were prepared, immobilized on different low-cost supports, and examined for potential biotechnological applications. Results To reduce costs of eventual scaling-up, the new lipases were obtained directly from crude cell extracts or from growth culture supernatants, and immobilized by simple adsorption on Accurel EP100, Accurel MP1000 and Celite®545. The enzymes evaluated were LipA and LipC from Pseudomonas sp. 42A2, a thermostable mutant of LipC, and LipI.3 from Pseudomonas CR611, which were produced in either homologous or heterologous hosts. Best immobilization results were obtained on Accurel EP100 for LipA and on Accurel MP1000 for LipC and its thermostable variant. Lip I.3, requiring a refolding step, was poorly immobilized on all supports tested (best results for Accurel MP1000). To test the behavior of immobilized lipases, they were assayed in triolein transesterification, where the best results were observed for lipases immobilized on Accurel MP1000. Conclusions The suggested protocol does not require protein purification and uses crude enzymes immobilized by a fast adsorption technique on low-cost supports, which makes the method suitable for an eventual scaling up aimed at biotechnological applications. Therefore, a fast, simple and economic method for lipase preparation and immobilization has been set up. The low price of the supports tested and the simplicity of the procedure, skipping the tedious and expensive purification steps, will contribute to cost reduction in biotechnological lipase-catalyzed processes. PMID:24755191

Thermochemical valorization and characterization of household biowaste.

PubMed

Vakalis, S; Sotiropoulos, A; Moustakas, K; Malamis, D; Vekkos, K; Baratieri, M

2017-12-01

Valorization of municipal solid waste (MSW), by means of energy and material recovery, is considered to be a crucial step for sustainable waste management. A significant fraction of MSW is comprised from food waste, the treatment of which is still a challenge. Therefore, the conventional disposal of food waste in landfills is being gradually replaced by recycling aerobic treatment, anaerobic digestion and waste-to-energy. In principle, thermal processes like combustion and gasification are preferred for the recovery of energy due to the higher electrical efficiency and the significantly less time required for the process to be completed when compared to biological process, i.e. composting, anaerobic digestion and transesterification. Nonetheless, the high water content and the molecular structure of biowaste are constraining factors in regard to the application of thermal conversion pathways. Investigating alternative solutions for the pre-treatment and more energy efficient handling of this waste fraction may provide pathways for the optimization of the whole process. In this study, by means of utilizing drying/milling as an intermediate step, thermal treatment of household biowaste has become possible. Household biowaste has been thermally processed in a bench scale reactor by means of torrefaction, carbonization and high temperature pyrolysis. According to the operational conditions, fluctuating fractions of biochar, bio-oil (tar) and syngas were recovered. The thermochemical properties of the feedstock and products were analyzed by means of Simultaneous Thermal Analysis (STA), Ultimate and Proximate analysis and Attenuated Total Reflectance (ATR). The analysis of the products shows that torrefaction of dried household biowaste produces an energy dense fuel and high temperature pyrolysis produces a graphite-like material with relatively high yield. Copyright © 2016 Elsevier Ltd. All rights reserved.

New Biofuel Integrating Glycerol into Its Composition Through the Use of Covalent Immobilized Pig Pancreatic Lipase

PubMed Central

Luna, Diego; Posadillo, Alejandro; Caballero, Verónica; Verdugo, Cristóbal; Bautista, Felipa M.; Romero, Antonio A.; Sancho, Enrique D.; Luna, Carlos; Calero, Juan

2012-01-01

By using 1,3-specific Pig Pancreatic lipase (EC 3.1.1.3 or PPL), covalently immobilized on AlPO4/Sepiolite support as biocatalyst, a new second-generation biodiesel was obtained in the transesterification reaction of sunflower oil with ethanol and other alcohols of low molecular weight. The resulting biofuel is composed of fatty acid ethyl esters and monoglycerides (FAEE/MG) blended in a molar relation 2/1. This novel product, which integrates glycerol as monoacylglycerols (MG) into the biofuel composition, has similar physicochemical properties compared to those of conventional biodiesel and also avoids the removal step of this by-product. The biocatalyst was found to be strongly fixed to the inorganic support (75%). Nevertheless, the efficiency of the immobilized enzyme was reduced to half (49.1%) compared to that of the free PPL. The immobilized enzyme showed a remarkable stability as well as a great reusability (more than 40 successive reuses) without a significant loss of its initial catalytic activity. Immobilized and free enzymes exhibited different reaction mechanisms, according to the different results in the Arrhenius parameters (Ln A and Ea). However, the use of supported PPL was found to be very suitable for the repetitive production of biofuel due to its facile recyclability from the reaction mixture. PMID:22949849

Cationic hemicellulose-based hydrogels for arsenic and chromium removal from aqueous solutions.

PubMed

Dax, Daniel; Chávez, María Soledad; Xu, Chunlin; Willför, Stefan; Mendonça, Regis Teixeira; Sánchez, Julio

2014-10-13

In this work the synthesis of hemicellulose-based hydrogels and their application for the removal of arsenic and chromium ions is described. In a first step O-acetyl galactoglucomannan (GGM) was subjected to a transesterification applying glycidyl methacrylate (GMA) for the synthesis of novel GGM macromonomers. Two distinguished and purified GGM fractions with molar mass of 7.1 and 28 kDa were used as starting materials. The resulting GGM macromonomers (GGM-MA) contained well-defined amounts of methacrylate groups as determined by (1)H NMR spectroscopy. Selected GGM-MA derivatives were consecutively applied as a crosslinker in the synthesis of tailored hydrogels using [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MeDMA) as monomer. The swelling rate of the hydrogels was determined and the coherence between the swelling rate and the hydrogel composition was examined. The morphology of the GGM-based hydrogels was analysed by SEM and the hydrogels revealed a high surface area and were assessed in respect to their ability to remove arsenate and chromate ions from aqueous solutions. The presented bio-based hydrogels are of high interest especially for the mining industries as a sustainable material for the treatment of their highly contaminated wastewaters. Copyright © 2014 Elsevier Ltd. All rights reserved.

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging.

PubMed

McDonald, A D; Jones, B J P; Nygren, D R; Adams, C; Álvarez, V; Azevedo, C D R; Benlloch-Rodríguez, J M; Borges, F I G M; Botas, A; Cárcel, S; Carrión, J V; Cebrián, S; Conde, C A N; Díaz, J; Diesburg, M; Escada, J; Esteve, R; Felkai, R; Fernandes, L M P; Ferrario, P; Ferreira, A L; Freitas, E D C; Goldschmidt, A; Gómez-Cadenas, J J; González-Díaz, D; Gutiérrez, R M; Guenette, R; Hafidi, K; Hauptman, J; Henriques, C A O; Hernandez, A I; Hernando Morata, J A; Herrero, V; Johnston, S; Labarga, L; Laing, A; Lebrun, P; Liubarsky, I; López-March, N; Losada, M; Martín-Albo, J; Martínez-Lema, G; Martínez, A; Monrabal, F; Monteiro, C M B; Mora, F J; Moutinho, L M; Muñoz Vidal, J; Musti, M; Nebot-Guinot, M; Novella, P; Palmeiro, B; Para, A; Pérez, J; Querol, M; Repond, J; Renner, J; Riordan, S; Ripoll, L; Rodríguez, J; Rogers, L; Santos, F P; Dos Santos, J M F; Simón, A; Sofka, C; Sorel, M; Stiegler, T; Toledo, J F; Torrent, J; Tsamalaidze, Z; Veloso, J F C A; Webb, R; White, J T; Yahlali, N

2018-03-30

A new method to tag the barium daughter in the double-beta decay of ^{136}Xe is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba^{++}) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (∼2  nm), and detected with a statistical significance of 12.9σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Demonstration of Single-Barium-Ion Sensitivity for Neutrinoless Double-Beta Decay Using Single-Molecule Fluorescence Imaging

NASA Astrophysics Data System (ADS)

McDonald, A. D.; Jones, B. J. P.; Nygren, D. R.; Adams, C.; Álvarez, V.; Azevedo, C. D. R.; Benlloch-Rodríguez, J. M.; Borges, F. I. G. M.; Botas, A.; Cárcel, S.; Carrión, J. V.; Cebrián, S.; Conde, C. A. N.; Díaz, J.; Diesburg, M.; Escada, J.; Esteve, R.; Felkai, R.; Fernandes, L. M. P.; Ferrario, P.; Ferreira, A. L.; Freitas, E. D. C.; Goldschmidt, A.; Gómez-Cadenas, J. J.; González-Díaz, D.; Gutiérrez, R. M.; Guenette, R.; Hafidi, K.; Hauptman, J.; Henriques, C. A. O.; Hernandez, A. I.; Hernando Morata, J. A.; Herrero, V.; Johnston, S.; Labarga, L.; Laing, A.; Lebrun, P.; Liubarsky, I.; López-March, N.; Losada, M.; Martín-Albo, J.; Martínez-Lema, G.; Martínez, A.; Monrabal, F.; Monteiro, C. M. B.; Mora, F. J.; Moutinho, L. M.; Muñoz Vidal, J.; Musti, M.; Nebot-Guinot, M.; Novella, P.; Palmeiro, B.; Para, A.; Pérez, J.; Querol, M.; Repond, J.; Renner, J.; Riordan, S.; Ripoll, L.; Rodríguez, J.; Rogers, L.; Santos, F. P.; dos Santos, J. M. F.; Simón, A.; Sofka, C.; Sorel, M.; Stiegler, T.; Toledo, J. F.; Torrent, J.; Tsamalaidze, Z.; Veloso, J. F. C. A.; Webb, R.; White, J. T.; Yahlali, N.; NEXT Collaboration

2018-03-01

A new method to tag the barium daughter in the double-beta decay of Xe 136 is reported. Using the technique of single molecule fluorescent imaging (SMFI), individual barium dication (Ba++ ) resolution at a transparent scanning surface is demonstrated. A single-step photobleach confirms the single ion interpretation. Individual ions are localized with superresolution (˜2 nm ), and detected with a statistical significance of 12.9 σ over backgrounds. This lays the foundation for a new and potentially background-free neutrinoless double-beta decay technology, based on SMFI coupled to high pressure xenon gas time projection chambers.

Femtosecond laser-induced periodic structure adjustments based on electron dynamics control: from subwavelength ripples to double-grating structures.

PubMed

Shi, Xuesong; Jiang, Lan; Li, Xin; Wang, Sumei; Yuan, Yanping; Lu, Yongfeng

2013-10-01

This study proposes a method for adjusting subwavelength ripple periods and the corresponding double-grating structures formed on fused silica by designing femtosecond laser pulse trains based on localized transient electron density control. Four near-constant period ranges of 190-490 nm of ripples perpendicular to the polarization are obtained by designing pulse trains to excite and modulate the surface plasmon waves. In the period range of 350-490 nm, the double-grating structure is fabricated in one step, which is probably attributable to the grating-assisted enhanced energy deposition and subsequent thermal effects.

Experimental Study of Combustion and Emissions Characteristics of Methyl Oleate, as a Surrogate for Biodiesel, in a Direct injection Diesel Engine

USDA-ARS?s Scientific Manuscript database

This study evaluates the combustion and emissions characteristics of methyl oleate (C19H36O2 CAS# 112-62) produced by transesterification from oleic acid, one of the main fatty acid components of biodiesel. The ignition delay of ultra-low sulfur diesel#2 (ULSD) and its blends with methyl oleate (O20...

Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples

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

Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije

Here, we describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. Moreover, the method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We also compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with evenmore » insulation layers produced by stepped anvils.« less

Using stepped anvils to make even insulation layers in laser-heated diamond-anvil cell samples

DOE PAGES

Du, Zhixue; Gu, Tingting; Dobrosavljevic, Vasilije; ...

2015-09-01

Here, we describe a method to make even insulation layers for high-pressure laser-heated diamond-anvil cell samples using stepped anvils. Moreover, the method works for both single-sided and double-sided laser heating using solid or fluid insulation. The stepped anvils are used as matched pairs or paired with a flat culet anvil to make gasket insulation layers and not actually used at high pressures; thus, their longevity is ensured. We also compare the radial temperature gradients and Soret diffusion of iron between self-insulating samples and samples produced with stepped anvils and find that less pronounced Soret diffusion occurs in samples with evenmore » insulation layers produced by stepped anvils.« less

Influence of the charge double layer on solid oxide fuel cell stack behavior

NASA Astrophysics Data System (ADS)

Whiston, Michael M.; Bilec, Melissa M.; Schaefer, Laura A.

2015-10-01

While the charge double layer effect has traditionally been characterized as a millisecond phenomenon, longer timescales may be possible under certain operating conditions. This study simulates the dynamic response of a previously developed solid oxide fuel cell (SOFC) stack model that incorporates the charge double layer via an equivalent circuit. The model is simulated under step load changes. Baseline conditions are first defined, followed by consideration of minor and major deviations from the baseline case. This study also investigates the behavior of the SOFC stack with a relatively large double layer capacitance value, as well as operation of the SOFC stack under proportional-integral (PI) control. Results indicate that the presence of the charge double layer influences the SOFC stack's settling time significantly under the following conditions: (i) activation and concentration polarizations are significantly increased, or (ii) a large value of the double layer capacitance is assumed. Under normal (baseline) operation, on the other hand, the charge double layer effect diminishes within milliseconds, as expected. It seems reasonable, then, to neglect the charge double layer under normal operation. However, careful consideration should be given to potential variations in operation or material properties that may give rise to longer electrochemical settling times.