The Knock-Limited Performance of Fuel Blends Containing Spiropentane, Methylenecyclobutane, Di-Tert-Butyl Ether, Methyl Tert-Butyl Ether, and Triptane

NASA Technical Reports Server (NTRS)

Meyer, Carl L.

1946-01-01

Tests show that at inlet-air temperatures of 250 deg F and 100 deg F the knock-limited performance of the base fuel of blends, leaded with 4 ml TEL per gallon and containing 20 percent spiropentane, was reduced at fuel/air ratios below 0.085. The 20 percent methylenecyclobutane reduced the knock-limited power of the base fuel at fuel/air ratios below 0.112. Di-tert-butyl ether, methyl-tert-butyl ether, and triptane increased the knock-limited power of the base fuel at all fuel/air ratios and at both temperatures.

Methyl tert-butyl ether (MTBE)

Integrated Risk Information System (IRIS)

Methyl tert - butyl ether ( MTBE ) ; CASRN 1634 - 04 - 4 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments f

IRIS Toxicological Review of Tert-Butyl Alcohol (Tert-Butanol) (Interagency Science Consultation Draft)

EPA Science Inventory

On April 29, 2016, the Toxicological Review of tert-Butyl Alcohol (tert-Butanol) (Public Comment Draft) was released for public comment. The draft Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and the Executive Office ...

The tert-butyl cation on zeolite Y: A theoretical and experimental study

NASA Astrophysics Data System (ADS)

Rosenbach, Nilton, Jr.; dos Santos, Alex P. A.; Franco, Marcelo; Mota, Claudio J. A.

2010-01-01

The structure and energy of the tert-butyl cation on zeolite Y were calculated at ONIOM(MP2(FULL)/6-31G( d, p):MNDO) level. The results indicated that the tert-butyl cation is a minimum and lies between 40 and 51 kJ mol -1 above in energy to the tert-butoxide, depending on the level of calculation. Both species are stabilized through hydrogen bonding interactions with the framework oxygen atoms. Experimental data of nucleophilic substitution of tert-butylchloride and bromide over NaY impregnated with NaCl or NaBr give additional support for the formation of the tert-butyl cation as a discrete intermediate on zeolite Y, in agreement with the calculations.

Neutral Lipid Biosynthesis in Engineered Escherichia coli: Jojoba Oil-Like Wax Esters and Fatty Acid Butyl Esters

PubMed Central

Kalscheuer, Rainer; Stöveken, Tim; Luftmann, Heinrich; Malkus, Ursula; Reichelt, Rudolf; Steinbüchel, Alexander

2006-01-01

Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms. PMID:16461689

Neutral lipid biosynthesis in engineered Escherichia coli: jojoba oil-like wax esters and fatty acid butyl esters.

PubMed

Kalscheuer, Rainer; Stöveken, Tim; Luftmann, Heinrich; Malkus, Ursula; Reichelt, Rudolf; Steinbüchel, Alexander

2006-02-01

Wax esters are esters of long-chain fatty acids and long-chain fatty alcohols which are of considerable commercial importance and are produced on a scale of 3 million tons per year. The oil from the jojoba plant (Simmondsia chinensis) is the main biological source of wax esters. Although it has a multitude of potential applications, the use of jojoba oil is restricted, due to its high price. In this study, we describe the establishment of heterologous wax ester biosynthesis in a recombinant Escherichia coli strain by coexpression of a fatty alcohol-producing bifunctional acyl-coenzyme A reductase from the jojoba plant and a bacterial wax ester synthase from Acinetobacter baylyi strain ADP1, catalyzing the esterification of fatty alcohols and coenzyme A thioesters of fatty acids. In the presence of oleate, jojoba oil-like wax esters such as palmityl oleate, palmityl palmitoleate, and oleyl oleate were produced, amounting to up to ca. 1% of the cellular dry weight. In addition to wax esters, fatty acid butyl esters were unexpectedly observed in the presence of oleate. The latter could be attributed to solvent residues of 1-butanol present in the medium component, Bacto tryptone. Neutral lipids produced in recombinant E. coli were accumulated as intracytoplasmic inclusions, demonstrating that the formation and structural integrity of bacterial lipid bodies do not require specific structural proteins. This is the first report on substantial biosynthesis and accumulation of neutral lipids in E. coli, which might open new perspectives for the biotechnological production of cheap jojoba oil equivalents from inexpensive resources employing recombinant microorganisms.

Process Intensification of Enzymatic Fatty Acid Butyl Ester Synthesis Using a Continuous Centrifugal Contactor Separator.

PubMed

Ilmi, Miftahul; Abduh, Muhammad Y; Hommes, Arne; Winkelman, Jozef G M; Hidayat, Chusnul; Heeres, Hero J

2018-01-17

Fatty acid butyl esters were synthesized from sunflower oil with 1-butanol using a homogeneous Rhizomucor miehei lipase in a biphasic organic (triglyceride, 1-butanol, hexane)- water (with enzyme) system in a continuous setup consisting of a cascade of a stirred tank reactor and a continuous centrifugal contactor separator (CCCS), the latter being used for integrated reaction and liquid-liquid separation. A fatty acid butyl ester yield up to 93% was obtained in the cascade when operated in a once-through mode. The cascade was run for 8 h without operational issues. Enzyme recycling was studied by reintroduction of the water phase from the CCCS outlet to the stirred tank reactor. Product yield decreased over time to an average of 50% of the initial value, likely due to accumulation of 1-butanol in water phase, loss of enzyme due to agglomeration, and the formation of a separate enzyme layer.

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric acid (H3BO3).

Code of Federal Regulations, 2013 CFR

2013-07-01

...-hydroxy, ester with boric acid (H3BO3). 721.1730 Section 721.1730 Protection of Environment ENVIRONMENTAL..., ester with boric acid (H3BO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric...

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric acid (H3BO3).

Code of Federal Regulations, 2014 CFR

2014-07-01

...-hydroxy, ester with boric acid (H3BO3). 721.1730 Section 721.1730 Protection of Environment ENVIRONMENTAL..., ester with boric acid (H3BO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric...

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric acid (H3BO3).

Code of Federal Regulations, 2012 CFR

2012-07-01

...-hydroxy, ester with boric acid (H3BO3). 721.1730 Section 721.1730 Protection of Environment ENVIRONMENTAL..., ester with boric acid (H3BO3). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric...

Process Intensification of Enzymatic Fatty Acid Butyl Ester Synthesis Using a Continuous Centrifugal Contactor Separator

PubMed Central

2017-01-01

Fatty acid butyl esters were synthesized from sunflower oil with 1-butanol using a homogeneous Rhizomucor miehei lipase in a biphasic organic (triglyceride, 1-butanol, hexane)– water (with enzyme) system in a continuous setup consisting of a cascade of a stirred tank reactor and a continuous centrifugal contactor separator (CCCS), the latter being used for integrated reaction and liquid–liquid separation. A fatty acid butyl ester yield up to 93% was obtained in the cascade when operated in a once-through mode. The cascade was run for 8 h without operational issues. Enzyme recycling was studied by reintroduction of the water phase from the CCCS outlet to the stirred tank reactor. Product yield decreased over time to an average of 50% of the initial value, likely due to accumulation of 1-butanol in water phase, loss of enzyme due to agglomeration, and the formation of a separate enzyme layer. PMID:29398779

Method for determination of methyl tert-butyl ether and its degradation products in water

USGS Publications Warehouse

Church, C.D.; Isabelle, L.M.; Pankow, J.F.; Rose, D.L.; Tratnyek, P.G.

1997-01-01

An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method can also give simultaneous identification of polar compounds that might occur as degradation products of gasoline oxygenates, such as TBA, TBF, TAA, methyl acetate, and acetone. When the method was applied to effluent from a column microcosm prepared with core material from an urban site in New Jersey, conversion of MTBE to TBA was observed after a lag period of 35 days. However, to date, analyses of water samples from six field sites using the DAI-GC/MS method have not produced evidence for the expected products of in situ degradation of MTBE.An analytical method is described that can detect the major alkyl ether compounds that are used as gasoline oxygenates (methyl tert-butyl ether, MTBE; ethyl tert-butyl ether, ETBE; and tert-amyl methyl ether, TAME) and their most characteristic degradation products (tert-butyl alcohol, TBA; tert-butyl formate, TBF; and tert-amyl alcohol, TAA) in water at sub-ppb concentrations. The new method involves gas chromatography (GC) with direct aqueous injection (DAI) onto a polar column via a splitless injector, coupled with detection by mass spectrometry (MS). DAI-GC/MS gives excellent agreement with conventional purge-and-trap methods for MTBE over a wide range of environmentally relevant concentrations. The new method

Synthesis and evaluation of L-cystathionine as a standard for amino acid analysis.

PubMed

Amino, Yusuke; Suzuki, Yumiko

2017-01-01

L-Cystathionine is a key nonprotein amino acid related to metabolic conditions. The quantitative determination of L-cystathionine in physiological fluids by amino acid analysis is important for clinical diagnosis; however, certified reference material for L-cystathionine with satisfactory purity, content, and quantity has been unavailable until recently. Consequently, a practical and simple method for the preparation of L-cystathionine was examined, which involves thioalkylation of N-tert-butoxycarbonyl-L-cysteine tert-butyl ester, derived from L-cystine, with (2S)-2-(tert-butoxycarbonyl)amino-4-iodobutanoic acid tert-butyl ester, derived from L-aspartic acid, to obtain L-cystathionine with protecting groups, followed by single-step deprotection under mild conditions. This method produces L-cystathionine in high purity (99.4%) and having sufficient percentage content according to amino acid analysis, which could be used as a standard for the amino acid analysis of physiological fluids.

Formal [4+2] cycloaddition of di-tert-butyl 2-ethoxycyclobutane-1,1-dicarboxylate with ketones or aldehydes and tandem lactonization.

PubMed

Okado, Ryohei; Nowaki, Aya; Matsuo, Jun-Ichi; Ishibashi, Hiroyuki

2012-01-01

A catalytic amount of tin(IV) chloride catalyzed formal [4+2] cycloaddition reaction of di-tert-butyl 2-ethoxycyclobutane-1,1-carboxylate with ketones or aldehydes to give diethyl 6-ethoxydihydro-2H-pyran-3,3(4H)-dicarboxylates, whereas two equivalents of trimethylsilyl triflate promoted tandem [4+2] cycloaddition and lactonization to afford 3-oxo-2,6-dioxabicyclo[2.2.2]octane-4-carboxylate esters.

Anaerobic degradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA).

PubMed

Finneran, K T; Lovley, D R

2001-05-01

The potential for anaerobic degradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) was investigated in laboratory incubations of sediments from a petroleum-contaminated aquifer and in aquatic sediments. The addition of humic substances (HS) stimulated the anaerobic degradation of MTBE in aquifer sediments in which Fe(III) was available as an electron acceptor. This is attributed to the fact that HS and other extracellular quinones can stimulate the activity of Fe(III)-reducing microorganisms by acting as an electron shuttle between Fe(III)-reducing microorganisms and insoluble Fe(III) oxides. MTBE was not degraded in aquifer sediments without Fe(III) and HS. [14C]-MTBE added to aquatic sediments adapted for anaerobic MTBE degradation was converted to 14CO2 in the presence or absence of HS or the HS analog, anthraquione-2,6-disulfonate. Unamended aquatic sediments produced 14CH4 as well as 14CO2 from [14C]-MTBE. The aquatic sediments also rapidly consumed TBA under anaerobic conditions and converted [14C]-TBA to 14CH4 and 14CO2. An adaptation period of ca. 250-300 days was required prior to the most rapid anaerobic MTBE degradation in both sediment types, whereas TBA was metabolized in the aquatic sediments without a lag. These results demonstrate that, under the appropriate conditions, MTBE and TBA can be degraded in the absence of oxygen. This suggests that it may be possible to design strategies for the anaerobic remediation of MTBE in petroleum-contaminated subsurface environments.

Reactivities of Substituted α-Phenyl-N-tert-butyl Nitrones

PubMed Central

2015-01-01

In this work, a series of α-phenyl-N-tert-butyl nitrones bearing one, two, or three substituents on the tert-butyl group was synthesized. Cyclic voltammetry (CV) was used to investigate their electrochemical properties and showed a more pronounced substituent effect for oxidation than for reduction. Rate constants of superoxide radical (O2•–) reactions with nitrones were determined using a UV–vis stopped-flow method, and phenyl radical (Ph•) trapping rate constants were measured by EPR spectroscopy. The effect of N-tert-butyl substitution on the charge density and electron density localization of the nitronyl carbon as well as on the free energies of nitrone reactivity with O2•– and HO2• were computationally rationalized at the PCM/B3LYP/6-31+G**//B3LYP/6-31G* level of theory. Theoretical and experimental data showed that the rates of the reaction correlate with the nitronyl carbon charge density, suggesting a nucleophilic nature of O2•– and Ph• addition to the nitronyl carbon atom. Finally, the substituent effect was investigated in cell cultures exposed to hydrogen peroxide and a correlation between the cell viability and the oxidation potential of the nitrones was observed. Through a combination of computational methodologies and experimental methods, new insights into the reactivity of free radicals with nitrone derivatives have been proposed. PMID:24968285

Vapor intrusion risk of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME) and ethyl tert-butyl ether (ETBE): A modeling study.

PubMed

Ma, Jie; Xiong, Desen; Li, Haiyan; Ding, Yi; Xia, Xiangcheng; Yang, Yongqi

2017-06-15

Vapor intrusion of synthetic fuel additives represents a critical yet still neglected problem at sites contaminated by petroleum fuel releases. This study used an advanced numerical model to investigate the vapor intrusion potential of fuel ether oxygenates methyl tert-butyl ether (MTBE), tert-amyl methyl ether (TAME), and ethyl tert-butyl ether (ETBE). Simulated indoor air concentration of these compounds can exceed USEPA indoor air screening level for MTBE (110μg/m 3 ). Our results also reveal that MTBE has much higher chance to cause vapor intrusion problems than TAME and ETBE. This study supports the statements made by USEPA in the Petroleum Vapor Intrusion (PVI) Guidance that the vertical screening criteria for petroleum hydrocarbons may not provide sufficient protectiveness for fuel additives, and ether oxygenates in particular. In addition to adverse impacts on human health, ether oxygenate vapor intrusion may also cause aesthetic problems (i.e., odour and flavour). Overall, this study points out that ether oxygenates can cause vapor intrusion problems. We recommend that USEPA consider including the field measurement data of synthetic fuel additives in the existing PVI database and possibly revising the PVI Guidance as necessary. Copyright © 2017 Elsevier B.V. All rights reserved.

Aerobic mineralization of MTBE and tert-butyl alcohol by stream-bed sediment microorganisms

USGS Publications Warehouse

Bradley, P.M.; Landmeyer, J.E.; Chapelle, F.H.

1999-01-01

Microorganisms indigenous to the stream-bed sediments at two gasoline- contaminated groundwater sites demonstrated significant mineralization of the fuel oxygenates, methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Up to 73% of [U-14C]-MTBE and 84% of [U-14C]-TBA were degraded to 14CO2 under mixed aerobic/anaerobic conditions. No significant mineralization was observed under strictly anaerobic conditions. The results indicate that, under the mixed aerobic/anaerobic conditions characteristic of stream-bed sediments, microbial processes may provide a significant environmental sink for MTBE and TBA delivered to surface water bodies by contaminated groundwater or by other sources.Microorganisms indigenous to the stream-bed sediments at two gasoline-contaminated groundwater sites demonstrated significant mineralization of the fuel oxygenates, methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Up to 73% of [U-14C]-MTBE and 84% of [U-14C]-TBA were degraded to 14CO2 under mixed aerobic/anaerobic conditions. No significant mineralization was observed under strictly anaerobic conditions. The results indicate that, under the mixed aerobic/anaerobic conditions characteristic of stream-bed sediments, microbial processes may provide a significant environmental sink for MTBE and TBA delivered to surface water bodies by contaminated groundwater or by other sources.

Phenyl 3,5-di-tert-butyl-2-hy­droxy­benzoate

PubMed Central

Carreño, Alexander; Preite, Marcelo; Manriquez, Juan Manuel; Vega, Andrés; Chavez, Ivonne

2010-01-01

The title mol­ecule, C21H26O3, has a six-membered planar carbon ring as the central core, substituted at position 1 with phen­oxy­carbonyl, at position 2 with hy­droxy and at positions 3 and 5 with tert-butyl groups. The structure shows two independent but very similar mol­ecules within the asymmetric unit. For both independent mol­ecules, the ester carboxyl­ate group is coplanar with the central core, as reflected by the small C—C—O—C torsion angles [179.95 (17) and 173.70 (17)°]. In contrast, the phenyl substituent is almost perpendicular to the carboxyl­ate –CO2 fragment, as reflected by C—O—C—C torsion angles, ranging from 74 to 80°. The coplanarity between the central aromatic ring and the ester carboxyl­ate –CO2– group allows the formation of an intra­molecular hydrogen bond, with O⋯O distances of 2.563 (2) and 2.604 (2) Å. PMID:21589569

The Synthesis and Isolation of N-Tert-Butyl-2-Phenylsuccinamic Acid and N-Tert-Butyl-3-Phenylsuccinamic Acid: An Undergraduate Organic Chemistry Laboratory Experiment

ERIC Educational Resources Information Center

Cesare, Victor; Sadarangani, Ishwar; Rollins, Janet; Costello, Dennis

2004-01-01

The facile, high yielding synthesis of phenylsuccinamic acids is described and one of these syntheses, the reaction of phenylsuccinic anhydride with tert-butylamine, is successfully modified and adapted for use in the second-semester organic chemistry laboratory at St. John's University. Succinamic acids are compounds that contain both the amide…

Temperature effect on tert-butyl alcohol (TBA) biodegradation kinetics in hyporheic zone soils.

PubMed

Greenwood, Mark H; Sims, Ronald C; McLean, Joan E; Doucette, William J

2007-09-19

Remediation of tert-butyl alcohol (TBA) in subsurface waters should be taken into consideration at reformulated gasoline contaminated sites since it is a biodegradation intermediate of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-butyl formate (TBF). The effect of temperature on TBA biodegradation has not been not been published in the literature. Biodegradation of [U 14C] TBA was determined using hyporheic zone soil microcosms. First order mineralization rate constants of TBA at 5 degrees C, 15 degrees C and 25 degrees C were 7.84 +/- 0.14 x 10-3, 9.07 +/- 0.09 x 10-3, and 15.3 +/- 0.3 x 10-3 days-1, respectively (or 2.86 +/- 0.05, 3.31 +/- 0.03, 5.60 +/- 0.14 years-1, respectively). Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A) and activation energy (Ea) of 154 day-1 and 23,006 mol/J, respectively. Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature.

Studies on the Conformational Landscape of Tert-Butyl Acetate Using Microwave Spectroscopy and Quantum Chemical Calculations

NASA Astrophysics Data System (ADS)

Zhao, YueYue; Mouhib, Halima; Li, Guohua; Stahl, Wolfgang; Kleiner, Isabelle

2014-06-01

The tert-Butyl acetate molecule was studied using a combination of quantum chemical calculations and molecular beam Fourier transform microwave spectroscopy in the 9 to 14 GHz range. Due to its rather rigid frame, the molecule possesses only two different conformers: one of Cs and one of C1 symmetry. According to ab initio calculations, the Cs conformer is 46 kJ/mol lower in energy and is the one observed in the supersonic jet. We report on the structure and dynamics of the most abundant conformer of tert-butyl acetate, with accurate rotational and centrifugal distortion constants. Additionally, the barrier to internal rotation of the acetyl methyl group was determined. Splittings due to the internal rotation of the methyl group of up to 1.3 GHz were observed in the spectrum. Using the programs XIAM and BELGI-Cs, we determine the barrier height to be about 113 cm-1 and compare the molecular parameters obtained from these two codes. Additionally, the experimental rotational constants were used to validate numerous quantum chemical calculations. This study is part of a larger project which aims at determining the lowest energy conformers of organic esters and ketones which are of interest for flavor or perfume synthetic applications Project partly supported by the PHC PROCOPE 25059YB.

IRIS Toxicological Review of Tert-Butyl Alcohol (Tert-Butanol) ...

EPA Pesticide Factsheets

EPA is developing an Integrated Risk Information System (IRIS) assessment of tert-butyl Alcohol (tert-butanol) and has released the public comment draft assessment for public comment and external peer review. When final, the assessment will appear on the IRIS database. This draft report is being released for public viewing and comment prior to a public meeting, providing an opportunity for the IRIS Program to engage in early discussions with stakeholders and the public on data that may be used to identify adverse health effects and characterize exposure-response relationships. EPA welcomes all comments on the draft literature search, preliminary evidence tables, and preliminary exposure-response arrays, such as remarks on the following: • the clarity and transparency of the materials; • the approach for identifying pertinent studies; • the selection of studies for data extraction to preliminary evidence tables and exposure-response arrays; • any methodological considerations that could affect the interpretation of or confidence in study results; and • any additional studies published or nearing publication that may provide data for the evaluation of human health hazard or dose-response relationships.

Temperature effect on tert-butyl alcohol (TBA) biodegradation kinetics in hyporheic zone soils

PubMed Central

Greenwood, Mark H; Sims, Ronald C; McLean, Joan E; Doucette, William J

2007-01-01

Background Remediation of tert-butyl alcohol (TBA) in subsurface waters should be taken into consideration at reformulated gasoline contaminated sites since it is a biodegradation intermediate of methyl tert-butyl ether (MTBE), ethyl tert-butyl ether (ETBE), and tert-butyl formate (TBF). The effect of temperature on TBA biodegradation has not been not been published in the literature. Methods Biodegradation of [U 14C] TBA was determined using hyporheic zone soil microcosms. Results First order mineralization rate constants of TBA at 5°C, 15°C and 25°C were 7.84 ± 0.14 × 10-3, 9.07 ± 0.09 × 10-3, and 15.3 ± 0.3 × 10-3 days-1, respectively (or 2.86 ± 0.05, 3.31 ± 0.03, 5.60 ± 0.14 years-1, respectively). Temperature had a statistically significant effect on the mineralization rates and was modelled using the Arrhenius equation with frequency factor (A) and activation energy (Ea) of 154 day-1 and 23,006 mol/J, respectively. Conclusion Results of this study are the first to determine mineralization rates of TBA for different temperatures. The kinetic rates determined in this study can be used in groundwater fate and transport modelling of TBA at the Ronan, MT site and provide an estimate for TBA removal at other similar shallow aquifer sites and hyporheic zones as a function of seasonal change in temperature. PMID:17877835

Sorption of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) to synthetic resins.

PubMed

Bi, Erping; Haderlein, Stefan B; Schmidt, Torsten C

2005-10-01

Methyl tert-butyl ether (MTBE) is a widely used gasoline oxygenate. Contamination of MTBE and its major degradation product tert-butyl alcohol (TBA) in groundwater and surface water has received great attention. However, sorption affinity and sorption mechanisms of MTBE and TBA to synthetic resins, which can be potentially used in removal of these contaminants from water, in passive sampling, or in enrichment of bacteria, have not been studied systemically. In this study, kinetic and equilibrium sorption experiments (single solute and binary mixtures) on four synthetic resins were conducted. The sorption affinity of the investigated sorbents for MTBE and TBA decreases in the order Ambersorb 563>Optipore L493>Amberlite XAD4>Amberlite XAD7, and all show higher sorption affinity for MTBE than for TBA. Binary experiments with o-xylene, a major compound of gasoline as co-contaminant, imply that all resins preferentially sorb o-xylene over MTBE or TBA, i.e., there is sorption competition. In the equilibrium aqueous concentration (Ceq) range (0.1-139.0 mg/L for MTBE, and 0.01-48.4 mg/L for TBA), experimental and modeling results as well as sorbent characteristics indicate that micropore filling and/or some other type of adsorption process (e.g., adsorption to specific sites of high sorption potential at low concentrations) rather than partitioning were the dominant sorption mechanisms. Optipore L493 has favourable sorption and desorption characteristics, and is a suitable sorbent, e.g., in bacteria enrichment or passive sampling for moderately polar compounds. However, for highly polar compounds such as TBA, Ambersorb 563 might be a better choice, especially in water treatment.

Synthesis, Anti-HCV, Antioxidant and Reduction of Intracellular Reactive Oxygen Species Generation of a Chlorogenic Acid Analogue with an Amide Bond Replacing the Ester Bond.

PubMed

Wang, Ling-Na; Wang, Wei; Hattori, Masao; Daneshtalab, Mohsen; Ma, Chao-Mei

2016-06-08

Chlorogenic acid is a well known natural product with important bioactivities. It contains an ester bond formed between the COOH of caffeic acid and the 3-OH of quinic acid. We synthesized a chlorogenic acid analogue, 3α-caffeoylquinic acid amide, using caffeic and quinic acids as starting materials. The caffeoylquinc acid amide was found to be much more stable than chlorogenic acid and showed anti-Hepatitis C virus (anti-HCV) activity with a potency similar to chlorogenic acid. The caffeoylquinc acid amide potently protected HepG2 cells against oxidative stress induced by tert-butyl hydroperoxide.

Absolute rate constants of alkoxyl radical reactions in aqueous solution. [Tert-butyl hydroperoxide

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

Erben-Russ, M.; Michel, C.; Bors, W.

1987-04-23

The pulse radiolysis technique was used to generate the alkoxyl radical derived from tert-butyl hydroperoxide (/sup t/BuOOH) in aqueous solution. The reactions of this radical with 2,2'-azinobis(3-ethyl-6-benzothiazolinesulfonate) (ABTS) and promethazine were monitored by kinetic spectroscopy. The unimolecular decay rate constant of the tert-butoxyl radical (/sup t/BuO) was determined to be 1.4 x 10/sup 6/ s/sup -1/. On the basis of this value, the rate constants for /sup t/BuO attack on quercetin, crocin, crocetin, ascorbate, isoascorbate, trolox c, glutathione, thymidine, adenosine, guanosine, and unsaturated fatty acids were determined. In addition, the reaction of /sup t/BuO with the polyunsaturated fatty acids (PUFA)more » was observed by directly monitoring the formation of the fatty acid pentadienyl radicals. Interestingly, the attack of /sup t/BuO on PUFA was found to be faster by about one order of magnitude as compared to the same reaction in a nonpolar solvent.« less

40 CFR 721.10072 - Benzene, 1,1′-methylenebis[4-isocyanato-, polymer with benzenedicarboxylic acid, butyl dialkyl...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-isocyanato-, polymer with benzenedicarboxylic acid, butyl dialkyl ester, poly[oxy(methyl-1,2-ethanediyl)], .alpha.-hydro-.omega.-hydroxy-, oxirane, alkyl-, polymer with oxirane, ether with propanepolyol and...-isocyanato-, polymer with benzenedicarboxylic acid, butyl dialkyl ester, poly[oxy(methyl-1,2-ethanediyl...

TREATMENT OF METHYL TERT-BUTYL ETHER CONTAMINATED WATER USING PHOTOCATALYSIS

EPA Science Inventory

The feasibility of photo-oxidation treatment of methyl tert-butyl ether (MTBE) in water was investigated in three ways, 1) using a slurry falling film photo-reactor, 2) a batch solar reactor system, and 3) a combination of air-stripping and gas phase photooxidation system. MTBE-c...

A new, direct analytical method using LC-MS/MS for fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible oils.

PubMed

Yamazaki, K; Ogiso, M; Isagawa, S; Urushiyama, T; Ukena, T; Kibune, N

2013-01-01

A new, direct analytical method for the determination of 3-chloro-1,2-propanediol fatty acid esters (3-MCPD esters) was developed. The targeted 3-MCPD esters included five types of monoester and 25 [corrected] types of diester. Samples (oils and fats) were dissolved in a mixture of tert-butyl methyl ether and ethyl acetate (4:1), purified using two solid-phase extraction (SPE) cartridges (C(18) and silica), then analysed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Five monoesters and five diesters with the same fatty acid group could be separated and quantified. Pairs of 3-MCPD diesters carrying the same two different fatty acid groups, but at reversed positions (sn-1 and sn-2), could not be separated and so were expressed as a sum of both compounds. The limits of quantification (LOQs) were estimated to be between 0.02 to 0.08 mg kg(-1), depending on the types of 3-MCPD ester. Repeatability expressed as relative standard deviation (RSD(r)%) varied from 5.5% to 25.5%. The new method was shown to be applicable to various commercial edible oils and showed levels of 3-MCPD esters varying from 0.58 to 25.35 mg kg(-1). The levels of mono- and diesters ranged from 0.10 to 0.69 mg kg(-1) and from 0.06 to 16 mg kg(-1), respectively.

40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2'-(1,2-diazenediyl)bis[2-methylbutanenitrile]- and 2,2'-(1,2-diazenediyl)bis[2-methylpropanenitrile]-initiated. 721.10326...

Effect of substrate interaction on the degradation of methyl tert-butyl ether, benzene, toluene, ethylbenzene, and xylene by Rhodococcus sp.

PubMed

Lee, Eun-Hee; Cho, Kyung-Suk

2009-08-15

It was examined the substrate interactions of benzene (B), tolulene (T), ethylbenzene (E), xylene (X), and methyl tert-butyl ether (M) in binary, ternary, quaternary, and quinary mixtures by Rhodococcus sp. EH831 that could aerobically degrade all of five single components. The specific degradation rates (SDRs) of B, T, E, X, and M were 234, 913, 131, 184 and 139 micromol g-dry cell weight (DCW)(-1)h(-1), respectively. In binary, ternary, quaternary, and quinary mixtures of them, ethylbenzene was the strongest inhibitor for the other substrates, and methyl tert-butyl ether was the weakest inhibitor. Interestingly, no degradation of benzene and methyl tert-butyl ether was found in the coexistence of ethylbenzene. The degradation of benzene followed only after toluene became exhausted when both was present. Ethylbenzene was least inhibited by methyl tert-butyl ether and most inhibited by toluene.

Peripheral substitution of pheophorbides and bacteriopheophorbides to promote inclusion into inert carrier systems for PDT

NASA Astrophysics Data System (ADS)

Roehrs, Susanne; Ruebner-Heuermann, Anja; Hartwich, G.; Scheer, H.; Moser, Joerg G.

1996-01-01

Pheophorbide a ethyl ester, pyropheophorbide a ethyl ester, and bacteriopheophorbide ethyl ester were substituted in 31-position with tert.butyl phenoxy or tert.butyl benzoic acid ester groups resp. in order to enhance affinity to (beta) -cyclodextrin dimers which form inclusion complexes with these photosensitizing drugs. This is a first step to construct inert transport complexes in order to photosensitize specifically cancer cells.

The Epoxidation of 2,5-Di-tert-butyl-1,4-benzoquinone: A Consecutive Reaction for the Physical Chemistry Laboratory.

ERIC Educational Resources Information Center

Hairfield, E. M.; And Others

1985-01-01

Reports a consecutive first-order reaction for which the concentrations of reactant, intermediate, and products can be determined simulataneously. This reaction is the epoxidation of 2,5-di-tert-butyl-1,4-benzoquinone (I) by alkaline hydroperoxidation using tert-butyl hydroperoxide and benzyltrimethylammonium hydroxide (Triton B) catalyst.…

Rotational Investigation of the Adducts of Formic Acid with Alcohols, Ethers and Esters

NASA Astrophysics Data System (ADS)

Evangelisti, Luca; Spada, Lorenzo; Li, Weixing; Caminati, Walther

2016-06-01

Mixtures of formic acid with methyl alcohol, with isopropyl alcohol, with tert-butyl alcohol, with dimethylether and with isopropylformiate have been supersonically expanded as pulsed jets. The obtained cool plumes have been analyzed by Fourier transform microwave spectroscopy. It has been possible to assign the rotational spectra of the 1:1 adducts of formic acid with tert-butyl alcohol, with dimethyl ether and with isopropylformiate. The conformational shapes and geometries of these adducts, as well as the topologies of their itermolecular hydrogen bonds will be presented. An explanation is given of the failure of the assignments of the rotational spectra of the adducts of formic acid with methyl alcohol and isopropyl alcohol.

PHOTOCATALYTIC OXIDATION OF METHYL-TERT-BUTYL ETHER FOR DRINKING WATER TREATMENT

EPA Science Inventory

The photo-oxidation of methyl tert-butyl ether (MTBE) in water was investigated to determine the feasibility of using photocatalysis for the treatment of MTBE-contaminated drinking water. The feasibility assessment was conducted using slurries of titanium dioxide in both a photo-...

40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2â²-(1,2-diazenediyl)bis[2-methylbutanenitrile]- and 2,2â²-(1,2-diazenediyl)bis[2-methylpropanenitrile]-initiated. 721.10326...

40 CFR 721.10326 - 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 2-Propenoic acid, 2-methyl-, methyl ester, polymer with butyl 2-propenoate, ethyl 2-propenoate, zinc 2-methyl-2-propenoate (1:2) and zinc 2-propenoate (1:2), 2,2â²-(1,2-diazenediyl)bis[2-methylbutanenitrile]- and 2,2â²-(1,2-diazenediyl)bis[2-methylpropanenitrile]-initiated. 721.10326...

Production of fatty acid butyl esters using the low cost naturally immobilized Carica papaya lipase.

PubMed

Su, Erzheng; Wei, Dongzhi

2014-07-09

In this work, the low cost naturally immobilized Carica papaya lipase (CPL) was investigated for production of fatty acid butyl esters (FABE) to fulfill the aim of reducing the lipase cost in the enzymatic butyl-biodiesel process. The CPL showed specificities to different alcohol acyl acceptors. Alcohols with more than three carbon atoms did not have negative effects on the CPL activity. The CPL catalyzed butanolysis for FABE production was systematically investigated. The reaction solvent, alcohol/oil molar ratio, enzyme amount, reaction temperature, and water activity all affected the butanolysis process. Under the optimized conditions, the highest conversion of 96% could be attained in 24 h. These optimal conditions were further applied to CPL catalyzed butanolysis of other vegetable oils. All of them showed very high conversion. The CPL packed-bed reactor was further developed, and could be operated continuously for more than 150 h. All of these results showed that the low cost Carica papaya lipase can be used as a promising lipase for biodiesel production.

STRUCTURES AND BINDING ENERGIES OF METHYL TERT-BUTYL ETHER-WATER COMPLEXES

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

INFLUENCE OF METHYL TERT-BUTYL ETHER (MTBE) ON LAKE WATER ALGAE

EPA Science Inventory

Methyl tert-butyl ether (MTBE) has been used as an octane booster in gasoline in the United States since the 1970s. MTBE use increased greatly in the 1990s with the implementation of the Clean Air Act Amendments of 1990. The MTBE enhanced a more complete combustion of fuel hydroc...

Lung toxicity and tumor promotion by hydroxylated derivatives of 2,6-di-tert-butyl-4-methylphenol (BHT) and 2-tert-butyl-4-methyl-6-iso-propylphenol: correlation with quinone methide reactivity.

PubMed

Kupfer, Rene; Dwyer-Nield, Lori D; Malkinson, Alvin M; Thompson, John A

2002-08-01

Acute pulmonary toxicity and tumor promotion by the food additive 2,6-di-tert-butyl-4-methylphenol (BHT) in mice are well documented. These effects have been attributed to either of two quinone methides, 2,6-di-tert-butyl-4-methylenecyclohexa-2,5-dienone (BHT-QM) formed through direct oxidation of BHT by pulmonary cytochrome P450 or a quinone methide formed by hydroxylation of a tert-butyl group of BHT (to form BHTOH) followed by oxidation of this metabolite to BHTOH-QM. BHTOH-QM is a more reactive electrophile compared to BHT-QM due to intramolecular interactions of the side-chain hydroxyl with the carbonyl oxygen. To further examine this bioactivation pathway, an analogue of BHTOH was prepared, 2-tert-butyl-6-(1'-hydroxy-1'-methyl)ethyl-4-methylphenol (BPPOH), that is structurally very similar to BHTOH but forms a quinone methide (BPPOH-QM) capable of more efficient intramolecular hydrogen bonding and, therefore, higher electrophilicity than BHTOH-QM. BPPOH-QM was synthesized and its reactivity with water, methanol, and glutathione determined to be >10-fold higher than that of BHTOH-QM. The conversions of BPPOH and BHTOH to quinone methides in lung microsomes from male BALB/cByJ mice were quantitatively similar, but in vivo the former was pneumotoxic at one-half of the dose required for the latter and one-eighth of the dose required for BHT, as determined by increased lung weight:body weight ratios following a single i.p. injection. Similar differences were found in the doses of BHT, BHTOH, or BPPOH required for tumor promotion after a single initiating dose of 3-methylcholanthrene followed by three weekly injections of the phenol. The downregulaton of calpain II, previously shown to accompany lung tumor promotion by BHT and BHTOH, also occurred with BPPOH. The correlation between biologic activities of these phenols and the reactivities of their corresponding quinone methides provides additional support for the role of BHTOH-QM as the principal metabolite

Bromine catalyzed conversion of S-tert-butyl groups into versatile and, for self-assembly processes accessible, acetyl-protected thiols.

PubMed

Blaszczyk, Alfred; Elbing, Mark; Mayor, Marcel

2004-10-07

The facile and efficient conversion of a tert-butyl protecting group to an acetyl protecting group for thiols by catalytic amounts of bromine in acetyl chloride and the presence of acetic acid has been developed. The fairly mild reaction conditions are of particular interest for new protecting group strategies for sulfur functionalised target structures. Copyright 2004 The Royal Society of Chemistry

Soluble, High Molecular Weight Polysilsesquioxanes with Carboxylate Functionalities

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

RAHIMIAN,KAMYAR; LOY,DOUGLAS A.; WHEELER,DAVID R.

2000-07-14

Trialkoxysilyl-containing monomers of the type (RO){sub 3}Si(CH{sub 2}){sub 3}C(O)OtBu (R = Me, Et) were prepared by hydrosilation of the corresponding vinylic tert-butyl esters CH{sub 3}CHCH{sub 2}C(O)OtBu. Acid- or base-catalyzed polymerization of the monomers leads to very high molecular weight polymers with relatively narrow polydispersities. The polymerization results in complete condensation of the alkoxy groups while the tert-butyl ester functionality remains fully intact. Partial or full deprotection of the tert-butyl group can easily be achieved to yield the corresponding carboxylic acid polymers. The ester and carboxylic acid functionalities of these new materials allow for their potential use in a variety ofmore » applications such as scavenging of heavy metals.« less

U.S. Geological Survey laboratory method for methyl tert-Butyl ether and other fuel oxygenates

USGS Publications Warehouse

Raese, Jon W.; Rose, Donna L.; Sandstrom, Mark W.

1995-01-01

Methyl tert-butyl ether (MTBE) was found in shallow ground-water samples in a study of 8 urban and 20 agricultural areas throughout the United States in 1993 and 1994 (Squillace and others, 1995, p. 1). The compound is added to gasoline either seasonally or year round in many parts of the United States to increase the octane level and to reduce carbon monoxide and ozone levels in the air. The U.S. Geological Survey (USGS) National Water Quality Laboratory (NWQL), near Denver, uses state-of-the-art technology to analyze samples for MTBE as part of the USGS water-quality studies. In addition, the NWQL offers custom analyses to determine two other fuel oxygenates--ethyl tert-butyl ether (ETBE) and tert-amyl methyl ether (TAME). The NWQL was not able to obtain a reference standard for tert-amyl ethyl ether (TAEE), another possible fuel oxygenate (Shelley and Fouhy, 1994, p. 63). The shallow ground-water samples were collected as part of the USGS National Water-Quality Assessment Program. These samples were collected from 211 urban wells or springs and 562 agricultural wells sampled by the USGS in 1993 and 1994. The wells were keyed to specific land-use areas to assess the effects of different uses on ground-water quality (Squillace and others, 1995, p. 2). Ground-water samples were preserved on site to pH less than or equal to 2 with a solution of 1:1 hydrochloric acid. All samples were analyzed at the NWQL within 2 weeks after collection. The purpose of this fact sheet is to explain briefly the analytical method implemented by the USGS for determining MTBE and other fuel oxygenates. The scope is necessarily limited to an overview of the analytical method (instrumentation, sample preparation, calibration and quantitation, identification, and preservation of samples) and method performance (reagent blanks, accuracy, and precision).

BIODEGRADATION OF METHYL TERT-BUTYL ETHER USING AN INNOVATIVE BIOMASS CONCENTRATOR REACTOR

EPA Science Inventory

The aerobic biodegradation of methyl tert-butyl ether (MTBE) was investigated using a pilot-scale Biomass Concentrator Reactor (BCR). The reactor was operated for a year at a flow rate of 2500 L/d of Cincinnati dechlorinated tap water and an influent MTBE concentration o...

BIODEGRADATION OF METHYL TERT-BUTYL ETHER AND BTEX AT VARYING HYDRAULIC RETENTION TIMES

EPA Science Inventory

The feasibility of biologically degrading methyl tert-butyl ether (MTBE) contaminated groundwater is dependent on the ability to degrade MTBE and its byproducts in the presence of other gasoline contaminants. This study investigates a mixed culture degrading both MTBE and benzene...

Thin PDMS Films Using Long Spin Times or Tert-Butyl Alcohol as a Solvent

PubMed Central

Koschwanez, John H.; Carlson, Robert H.; Meldrum, Deirdre R.

2009-01-01

Thin polydimethylsiloxane (PDMS) films are frequently used in “lab on a chip” devices as flexible membranes. The common solvent used to dilute the PDMS for thin films is hexane, but hexane can swell the underlying PDMS substrate. A better solvent would be one that dissolves uncured PDMS but doesn't swell the underlying substrate. Here, we present protocols and spin curves for two alternatives to hexane dilution: longer spin times and dilution in tert-butyl alcohol. The thickness of the PDMS membranes under different spin speeds, spin times, and PDMS concentrations was measured using an optical profilometer. The use of tert-butyl alcohol to spin thin PDMS films does not swell the underlying PDMS substrate, and we have used these films to construct multilayer PDMS devices. PMID:19238212

Correlation of the rates of solvolysis of tert-butyl chlorothioformate and observations concerning the reaction mechanism

PubMed Central

Kyong, Jin Burm; Lee, Yelin; D’Souza, Malcolm John; Kevill, Dennis Neil; Kevill, Dennis Neil

2012-01-01

The “parent” tertiary alkyl chloroformate, tert-butyl chloroformate, is unstable, but the tert-butyl chlorothioformate (1) is of increased stability and a kinetic investigation of the solvolyses is presented. Analyses in terms of the simple and extended Grunwald-Winstein equations are carried out. The original one-term equation satisfactorily correlates the data with a sensitivity towards changes in solvent ionizing power of 0.73 ±0.03. When the two-term equation is applied, the sensitivity towards changes in solvent nucleophilicity of 0.13 ± 0.09 is associated with a high (0.17) probability that the term that it governs is not statistically significant. PMID:23538747

Vibrational and reorientationl relaxation in liquid tert-butyl bromide and tert-butyl bromide- d9

NASA Astrophysics Data System (ADS)

Szostak, R.; Hawranek, J. P.

1992-12-01

The vibrational and reorientational correlation functions of the ν s(CBr) mode in liquid tert-butyl bromide (TBBr) and in its deuterated analogue (TBBr- d9) were determined from Raman bandshapes. The Kubo product δτ m obtained by fitting the Rothschild equation to experimental data amounts to 0.36-0.45 for the studied bands, which indicates a fairly fast modulation regime in these systems. The approximation of experimental rotational correlation functions with the help of the J-diffusion model yields values of 0.11-0.12ps for the angular momentum correlation time. The second-order rotational correlation times (1.7-2.0ps) agree well with the NMR results of D.W. Aksnes, K. Ramstad and O.P. Björlykke, Magn. Reson. Chem., 25 (1987) 1063. Selected bandshape parameters for δ(CCC) in both compounds, ϱ(CH 3) in TBBr and ν s(CC) in TBBR- d9 were also quoted.

Distribution of methyl tert-butyl ether (MTBE) and selected water-quality constituents in the surficial aquifer at the Dover National Test Site, Dover Air Force Base, Delaware, 2001

USGS Publications Warehouse

Stewart, Marie; Guertal, William R.; Barbaro, Jeffrey R.; McHale, Timothy J.

2004-01-01

A joint study by the Dover National Test Site, Dover Air Force Base, Delaware, and the U.S. Geological Survey was conducted from June 27 through July 18, 2001, to determine the spatial distribution of the gasoline oxygenate additive methyl tert-butyl ether and selected water-quality constituents in the surficial aquifer underlying the Dover National Test Site. This report provides a summary assessment of the distribution of methyl tert-butyl ether and a preliminary screening of selected constituents that may affect natural attenuation and remediation demonstrations at the Dover National Test Site. The information gathered during this study is designed to assist potential remedial investigators who are considering conducting a methyl tert-butyl ether remedial demonstration at the test site. In addition, the study supported a planned enhanced bioremediation demonstration and assisted the Dover National Test Site in identifying possible locations for future methyl tert-butyl ether remediation demonstrations. A direct-push drill rig was used to collect a total of 147 ground-water samples (115 VOC samples and 32 quality-assurance samples) at varying depths. Volatile organic compounds were above the method reporting limits in 59 of the 115 ground-water samples. The concentrations ranged from below detection limits to maximum values of 12.4 micrograms per liter of cis-1,2-dichloro-ethene, 1.14 micrograms per liter of trichloro-ethene, 2.65 micrograms per liter of tetrachloro-ethene, 1,070 micrograms per liter of methyl tert-butyl ether, 4.36 micrograms per liter of benzene, and 1.8 micrograms per liter of toluene. Vinyl chloride, ethylbenzene, p,m-xylene, and o-xylene were not detected in any of the samples collected during this investigation. Methyl tert-butyl ether was detected in 47 of the 115 ground-water samples. The highest concentrations of methyl tert-butyl ether were detected in the surficial aquifer from ?4.6 to 6.4 feet mean sea level; however, methyl tert-butyl

Novel syn intramolecular pathway in base-catalyzed 1,2-elimination reactions of beta-acetoxy esters.

PubMed

Mohrig, Jerry R; Carlson, Hans K; Coughlin, Jane M; Hofmeister, Gretchen E; McMartin, Lea A; Rowley, Elizabeth G; Trimmer, Elizabeth E; Wild, Andrew J; Schultz, Steve C

2007-02-02

As part of a comprehensive investigation of electronic effects on the stereochemistry of base-catalyzed 1,2-elimination reactions, we observed a new syn intramolecular pathway in the elimination of acetic acid from beta-acetoxy esters and thioesters. 1H and 2H NMR investigation of reactions using stereospecifically labeled tert-butyl (2R*,3R*)-3-acetoxy-2,3-2H2-butanoate (1) and its (2R*,3S*) diastereomer (2) shows that 23 +/- 2% syn elimination occurs. The elimination reactions were catalyzed with KOH or (CH3)4NOH in ethanol/water under rigorously non-ion-pairing conditions. By contrast, the more sterically hindered beta-trimethylacetoxy ester produces only 6 +/- 1% syn elimination. These data strongly support an intramolecular (Ei) syn path for elimination of acetic acid, most likely through the oxyanion produced by nucleophilic attack at the carbonyl carbon of the beta-acetoxy group. The analogous thioesters, S-tert-butyl (2R*,3R*)-3-acetoxy-2,3-2H2-butanethioate (3) and its (2R*,3S*) diastereomer (4), showed 18 +/- 2% syn elimination, whereas the beta-trimethylacetoxy substrate gave 5 +/- 1% syn elimination. The more acidic thioester substrates do not produce an increased amount of syn stereoselectivity even though their elimination reactions are at the E1cb interface.

ATTENUATION OF METHYL TERT-BUTYL ETHER IN WATER USING SUNLIGHT AND A PHOTOCATALYST

EPA Science Inventory

The use of methyl tert-butyl ether (MTBE) as a gasoline additive has resulted in increasing pollution of ground water. Most of the conventional treatment technologies are inefficient or costly when the initial concentration of MTBE is low (<200 ug/L). In order to find an eco-frie...

OCCURRENCE OF METYL TERT-BUTYL ETHER (MTBE) AT FIVE MARINAS IN LAKE TEXOMA

EPA Science Inventory

Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at loc...

Synthetic phenolic antioxidants, including butylated hydroxytoluene (BHT), in resin-based dental sealants

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

Wang, Wei; Kannan, Pranav; Xue, Jingchuan

Resin-based dental sealants (also referred to as pit-and-fissure sealants) have been studied for their contribution to bisphenol A (BPA) exposure in children. Nevertheless, little attention has been paid to the occurrence of other potentially toxic chemicals in dental sealants. In this study, the occurrence of six synthetic phenolic antioxidants (SPAs), including 2,6-di-tert-butyl-4-hydroxytoluene (BHT), 2,6-di-tert-butyl-4-(hydroxyethyl)phenol (BHT-OH), 3,5-di-tert-butyl-4-hydroxy-benzaldehyde (BHT-CHO), 2,6-di-tert-butylcyclohexa-2,5-diene-1,4-dione (BHT-Q), 3,5-di-tert-butyl-4-hydroxybenzoic acid (BHT-COOH) and 2-tert-butyl-4-methoxyphenol (BHA), was examined in 63 dental sealant products purchased from the U.S. market. BHT was found in all dental sealants at median and maximum concentrations of 56.8 and 1020 µg/g, respectively. The metabolites of BHT andmore » BHA were detected in 39–67% of samples, at concentration ranges of« less

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric acid (H3BO3).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Poly(oxy-1,2-ethanediyl), α-butyl-Ï... Significant New Uses for Specific Chemical Substances § 721.1730 Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy...) The chemical substance identified as poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric...

40 CFR 721.1730 - Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric acid (H3BO3).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Poly(oxy-1,2-ethanediyl), α-butyl-Ï... Significant New Uses for Specific Chemical Substances § 721.1730 Poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy...) The chemical substance identified as poly(oxy-1,2-ethanediyl), α-butyl-ω-hydroxy, ester with boric...

n-Alkane assimilation and tert-butyl alcohol (TBA) oxidation capacity in Mycobacterium austroafricanum strains.

PubMed

Lopes Ferreira, Nicolas; Mathis, Hugues; Labbé, Diane; Monot, Frédéric; Greer, Charles W; Fayolle-Guichard, Françoise

2007-06-01

Mycobacterium austroafricanum IFP 2012, which grows on methyl tert-butyl ether (MTBE) and on tert-butyl alcohol (TBA), the main intermediate of MTBE degradation, also grows on a broad range of n-alkanes (C2 to C16). A single alkB gene copy, encoding a non-heme alkane monooxygenase, was partially amplified from the genome of this bacterium. Its expression was induced after growth on n-propane, n-hexane, n-hexadecane and on TBA but not after growth on LB. The capacity of other fast-growing mycobacteria to grow on n-alkanes (C1 to C16) and to degrade TBA after growth on n-alkanes was compared to that of M. austroafricanum IFP 2012. We studied M. austroafricanum IFP 2012 and IFP 2015 able to grow on MTBE, M. austroafricanum IFP 2173 able to grow on isooctane, Mycobacterium sp. IFP 2009 able to grow on ethyl tert-butyl ether (ETBE), M. vaccae JOB5 (M. austroaafricanum ATCC 29678) able to degrade MTBE and TBA and M. smegmatis mc2 155 with no known degradation capacity towards fuel oxygenates. The M. austroafricanum strains grew on a broad range of n-alkanes and three were able to degrade TBA after growth on propane, hexane and hexadecane. An alkB gene was partially amplified from the genome of all mycobacteria and a sequence comparison demonstrated a close relationship among the M. austroafricanum strains. This is the first report suggesting the involvement of an alkane hydroxylase in TBA oxidation, a key step during MTBE metabolism.

Simultaneous Clostridial fermentation, lipase-catalyzed esterification, and ester extraction to enrich diesel with butyl butyrate.

PubMed

van den Berg, Corjan; Heeres, Arjan S; van der Wielen, Luuk A M; Straathof, Adrie J J

2013-01-01

The recovery of 1-butanol from fermentation broth is energy-intensive since typical concentrations in fermentation broth are below 20 g L(-1). To prevent butanol inhibition and high downstream processing costs, we aimed at producing butyl esters instead of 1-butanol. It is shown that it is possible to perform simultaneously clostridial fermentation, esterification of the formed butanol to butyl butyrate, and extraction of this ester by hexadecane. The very high partition coefficient of butyl butyrate pulls the esterification towards the product side even at fermentation pH and relatively low butanol concentrations. The hexadecane extractant is a model diesel compound and is nontoxic to the cells. If butyl butyrate enriched diesel can directly be used as car fuel, no product recovery is required. A proof-of-principle experiment for the one-pot bio-ester production from glucose led to 5 g L(-1) butyl butyrate in the hexadecane phase. The principle may be extended to a wide range of esters, especially to longer chain ones. Copyright © 2012 Wiley Periodicals, Inc.

Protective effect of vanilloids against tert-butyl hydroperoxide-induced oxidative stress in vero cells culture.

PubMed

Rosa, Antonella; Atzeri, Angela; Deiana, Monica; Melis, M Paola; Incani, Alessandra; Corona, Giulia; Loru, Debora; Appendino, Giovanni; Dessì, M Assunta

2008-05-28

This study investigated the effect of synthetic capsiate, a simplified analogue of capsiate, and vanillyl alcohol on the oxidative stress induced by tert-butyl hydroperoxide (TBH) in a line of fibroblasts derived from monkey kidney (Vero cells). In response to the TBH-mediated oxidative stress, a reduction of the levels of total unsaturated fatty acids and cholesterol was observed, and a rise in the concentrations of conjugated dienes fatty acids hydroperoxides and 7-ketocholesterol. Pretreatment with both synthetic capsiate and vanillyl alcohol preserved Vero cells from oxidative damage and showed a remarkable protective effect on the reduction of the levels of total unsaturated fatty acids and cholesterol, inhibiting the increase of MDA, conjugated dienes fatty acids hydroperoxides, and 7-ketocholesterol. Both compounds were effective against peroxidation of cell membrane lipids induced by TBH, with synthetic capsiate essentially acting as a pro-drug of vanillyl alcohol, its hydrophilic hydrolytic derivative.

Di-tert-butyl-chlorido(N,N-dibenzyl-dithio-carbamato)tin(IV).

PubMed

Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R T

2011-02-26

The Sn(IV) atom in the title diorganotin dithio-carbamate, [Sn(C(4)H(9))(2)(C(15)H(14)NS(2))Cl], is penta-coordinated by an asymmetrically coordinating dithio-carbamate ligand, a Cl atom and two C atoms of the Sn-bound tert-butyl groups. The resulting C(2)ClS(2) donor set defines a coordination geometry inter-mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former.

40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

..., Calcium Salt Maleic Anhydride Methacrylic Acid *Methacrylic Acid Esters Methane Methyl Ethyl Ketone Methyl Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n... Acid Nylon Salt Oxalic Acid *Oxo Aldehydes—Alcohols Pentaerythritol Pentane *Pentenes *Petroleum...

40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

..., Calcium Salt Maleic Anhydride Methacrylic Acid *Methacrylic Acid Esters Methane Methyl Ethyl Ketone Methyl Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n... Acid Nylon Salt Oxalic Acid *Oxo Aldehydes—Alcohols Pentaerythritol Pentane *Pentenes *Petroleum...

40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

..., Calcium Salt Maleic Anhydride Methacrylic Acid *Methacrylic Acid Esters Methane Methyl Ethyl Ketone Methyl Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n... Acid Nylon Salt Oxalic Acid *Oxo Aldehydes—Alcohols Pentaerythritol Pentane *Pentenes *Petroleum...

40 CFR 414.70 - Applicability; description of the bulk organic chemicals subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

..., Calcium Salt Maleic Anhydride Methacrylic Acid *Methacrylic Acid Esters Methane Methyl Ethyl Ketone Methyl Methacrylate Methyl Tert-Butyl Ether Methylisobutyl Ketone *n-Alkanes n-Butyl Alcohol n-Butylacetate n... Acid Nylon Salt Oxalic Acid *Oxo Aldehydes—Alcohols Pentaerythritol Pentane *Pentenes *Petroleum...

EVALUATION OF METHYL TERT-BUTYL ETHER (MTBE) AS AN INTERFERENCE ON COMMERCIAL BREATH-ALCOHOL ANALYZERS

EPA Science Inventory

Anecdotal reports suggest that high environmental or occupational exposures to the fuel oxygenate methyl tert-butyl ether (MTBE) may result in breath concentrations that are sufficiently elevated to cause a false positive on commercial breath-alcohol analyzers. We evaluated th...

Influence of thermocleavable functionality on organic field-effect transistor performance of small molecules

NASA Astrophysics Data System (ADS)

Mahale, Rajashree Y.; Dharmapurikar, Satej S.; Chini, Mrinmoy Kumar; Venugopalan, Vijay

2017-06-01

Diketopyrrolopyrrole based donor-acceptor-donor conjugated small molecules using ethylene dioxythiophene as a donor was synthesized. Electron deficient diketopyrrolopyrrole unit was substituted with thermocleavable (tert-butyl acetate) side chains. The thermal treatment of the molecules at 160 °C eliminated the tert-butyl ester group results in the formation of corresponding acid. Optical and theoretical studies revealed that the molecules adopted a change in molecular arrangement after thermolysis. The conjugated small molecules possessed p-channel charge transport characteristics in organic field effect transistors. The charge carrier mobility was increased after thermolysis of tert-butyl ester group to 5.07 × 10-5 cm2/V s.

Synthesis and characterization of novel chiral ionic liquids and investigation of their enantiomeric recognition properties.

PubMed

Bwambok, David K; Marwani, Hadi M; Fernand, Vivian E; Fakayode, Sayo O; Lowry, Mark; Negulescu, Ioan; Strongin, Robert M; Warner, Isiah M

2008-02-01

We report the synthesis and characterization of amino acid ester based chiral ionic liquids, derived from L- and D-alanine tert butyl ester chloride. The synthesis was accomplished via an anion metathesis reaction between commercially available L- and D-alanine tert butyl ester chloride using a variety of counterions such as lithium bis (trifluoromethane) sulfonimide, silver nitrate, silver lactate, and silver tetrafluoroborate. Both enantiomeric forms were obtained as confirmed by bands of opposite sign in the circular dichroism spectra. The L- and D-alanine tert butyl ester bis (trifluoromethane) sulfonimide were obtained as liquids at room temperature and intriguingly exhibited the highest thermal stability (up to 263 degrees C). In addition, the ionic liquids demonstrated enantiomeric recognition ability as evidenced by splitting of racemic Mosher's sodium salt signal using a liquid state (19)F nuclear magnetic resonance (NMR) and fluorescence spectroscopy. The L- and D-alanine tert butyl ester chloride resulted in solid salts with nitrate, lactate, and tetrafluoroborate anions. This illustrates the previously observed tunability of ionic liquid synthesis, resulting in ionic liquids of varying properties as a function of varying the anion.

Formation of Germa-ketenimine on the Ge(100) Surface by Adsorption of tert-Butyl Isocyanide.

PubMed

Shong, Bonggeun; Yoo, Jong Suk; Sandoval, Tania E; Bent, Stacey F

2017-06-28

Reactions of the (100) surfaces of Ge and Si with organic molecules have been generally understood within the concept of "dimers" formed by the 2 × 1 surface reconstruction. In this work, the adsorption of tert-butyl isocyanide on the Ge(100)-2 × 1 surface at large exposures is investigated under ultrahigh vacuum conditions. A combination of infrared spectroscopy, X-ray photoelectron spectroscopy, and temperature-programmed desorption experiments along with dispersion-corrected density functional theory calculations is used to determine the surface products. Upon adsorption of a dense monolayer of tert-butyl isocyanide, a product whose structure resembles a germa-ketenimine (N=C=Ge) with σ donation toward and π back-donation from the Ge(100) surface appears. Formation of this structure involves divalent-type surface Ge atoms that arise from cleavage of the Ge(100)-2 × 1 surface dimers. Our results reveal an unprecedented class of reactions of organic molecules at the Ge(100) surface.

INHALATION EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) USING CONTINUOUS BREATH ANALYSIS

EPA Science Inventory

The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced haza...

Determination of arsenic species in solid matrices utilizing supercritical fluid extraction coupled with gas chromatography after derivatization with thioglycolic acid n-butyl ester.

PubMed

Wang, Zhifeng; Cui, Zhaojie

2016-12-01

A method using derivatization and supercritical fluid extraction coupled with gas chromatography was developed for the analysis of dimethylarsinate, monomethylarsonate and inorganic arsenic simultaneously in solid matrices. Thioglycolic acid n-butyl ester was used as a novel derivatizing reagent. A systematic discussion was made to investigate the effects of pressure, temperature, flow rate of the supercritical CO 2 , extraction time, concentration of the modifier, and microemulsion on extraction efficiency. The application for real environmental samples was also studied. Results showed that thioglycolic acid n-butyl ester was an effective derivatizing reagent that could be applied for arsenic speciation. Using methanol as modifier of the supercritical CO 2 can raise the extraction efficiency, which can be further enhanced by adding a microemulsion that contains Triton X-405. The optimum extraction conditions were: 25 MPa, 90°C, static extraction for 10 min, dynamic extraction for 25 min with a flow rate of 2.0 mL/min of supercritical CO 2 modified by 5% v/v methanol and microemulsion. The detection limits of dimethylarsinate, monomethylarsonate, and inorganic arsenic in solid matrices were 0.12, 0.26, and 1.1 mg/kg, respectively. The optimized method was sensitive, convenient, and reliable for the extraction and analysis of different arsenic species in solid samples. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In vitro study comparing the ability of mono-octanoin and mono-octanoin plus methyl tert-butyl ether to dissolve biliary stones.

PubMed

Tritapepe, R; Cesana, B

1996-01-01

This in vitro study compared the gallstone dissolution rates of mono-octanoin, mono-octanoin plus 10% distilled water, and mono-octanoin plus methyl tert-butyl ether 2:1. Sixteen stones were treated with each solvent at a slow perfusion rate of 3-4 ml/h and a rapid perfusion rate of 2.5 ml/30 min with 20-sec instillation/aspiration cycles, both with and without bile. The stones were weighed before, and 3, 6, 12 and 24 hrs after the start of treatment: the solvent was changed every 30 min. After 24 hrs of instillation/aspiration without bile, the mono-octanoin/methyl tert-butyl ether mixture reduced the weight of the stones by 93%, mono-octanoin plus water by 63%, and mono-octanoin alone by 52%; with bile, the figures were, respectively, 86%, 42% and 40%. The mono-octanoin/methyl tert-butyl ether mixture thus took approximately half the time needed by the other two preparations to dissolve the stones to the same extent, a finding which may be relevant for the clinical dissolution of bile duct stones.

Reaction of 1H-1-oxo-2,4,6,8-tetrakis(tert-butyl)phenoxazine with certain group II-IV metals

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

Karsanov, I.V.; Ivakhnenko, E.P.; Khandkarova, V.S.

1987-07-10

It has already been shown that 2-amino-4,6-di(tert-butyl)phenol reacts with 3,5-di(tert-butyl)-o-benzoquinone to form 1H-1-oxo-2,4,6,8-tetrakis(tert-butyl)phenoxazine (I), which is readily reduced by alkali metals to the corresponding semiquinone anion-radical (II), and further to the diamagnetic dianion (IIA). They made use of this ability of (I) to undergo reduction to prepare anion-radical salts with different group II-IV metals in the form of their amalgams. In the EPR spectrum of the anion-radical complex (III) formed in the reduction of (I) by a thallium amalgam, the HFI constants of the unpaired electron with magnetic nuclei of the organic ligand are close to those of the K-saltmore » (II), and a substantial HFI is observed with the /sup 203,205/Tl nuclei. This unequivocally proves that the complex has a semiquinone structure, since an HFI on the /sup 203,205/Tl nuclei of such an order of magnitude is characteristic of o-benzoquinone salts with a thallium cation.« less

Synchrotron Photoionization Investigation of the Oxidation of Ethyl tert-Butyl Ether.

PubMed

Winfough, Matthew; Yao, Rong; Ng, Martin; Catani, Katherine; Meloni, Giovanni

2017-02-23

The oxidation of ethyl tert-butyl ether (ETBE), a widely used fuel oxygenated additive, is investigated using Cl atoms as initiators in the presence of oxygen. The reaction is carried out at 293, 550, and 700 K. Reaction products are probed by a multiplexed chemical kinetics photoionization mass spectrometer coupled with the synchrotron radiation produced at the Advanced Light Source (ALS) of the Lawrence Berkeley National Laboratory. Products are identified on the basis of mass-to-charge ratio, ionization energies, and shape of photoionization spectra. Reaction pathways are proposed together with detected primary products.

(N-Benzyl-N-ethyl-dithio-carbamato)di-tert-butyl-chloridotin(IV).

PubMed

Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R T

2011-02-26

The Sn(IV) atom in the title diorganotin dithio-carbamate, [Sn(C(4)H(9))(2)Cl(C(10)H(12)NS(2))], is penta-coordinated by an asymmetrically coordinating dithio-carbamate ligand, a Cl and two C atoms of the Sn-bound tert-butyl groups. The resulting C(2)ClS(2) donor set defines a coordination geometry inter-mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. In the crystal structure, C-H⋯π contacts link centrosymmetrically related mol-ecules into dimeric aggregates.

Strontium (II)-Selective Potentiometric Sensor Based on Ester Derivative of 4-tert-butylcalix(8)arene in PVC Matrix

PubMed Central

Jain, Ajay K.; Gupta, Vinod K.; Raisoni, Jitendra R.

2004-01-01

Membranes of 4-tert-butylcalix(8)arene-octaacetic acid octaethyl ester (I) as an electroactive material, sodium tetraphenyl borate (NaTPB) as an anion excluder, and tri-n-butyl phosphate (TBP) as a solvent mediator in poly(vinyl chloride) (PVC) matrix have been tried for a strontium-selective sensor. The best performance was exhibited by the membrane having a composition 5:100:150:2 (I: PVC: TBP: NaTPB (w/w)). This sensor exhibits a good potentiometric response to Sr2+ over a wide concentration range (3.2 × 10 –5 –1.0 × 10 –1 M) with a Nernstian slope (30 mV/ decade). The response time of the sensor is 10 s and it has been used for a period of four months without any drift in potentials. The selectivity coefficient values are in the order of 0.01 for mono-, bi-, and trivalent cations which indicate a good selectivity for Sr2+ over a large number of cations. The useful pH range for the sensor was found to be 3-10 and it works well in mixtures with non-aqueous content up to 25 % (v/v). The sensor has been used as an indicator electrode in the potentiometric titration of Sr2+ against EDTA.

A series of (E)-5-(arylideneamino)-1-tert-butyl-1H-pyrrole-3-carbonitriles and their reduction products to secondary amines: syntheses and X-ray structural studies.

PubMed

Macías, Mario A; Castillo, Juan Carlos; Portilla, Jaime

2018-01-01

An efficent access to a series of N-(pyrrol-2-yl)amines, namely (E)-1-tert-butyl-5-[(4-chlorobenzylidene)amino]-1H-pyrrole-3-carbonitrile, C 16 H 16 ClN 3 , (7a), (E)-1-tert-butyl-5-[(2,4-dichlorobenzylidene)amino]-1H-pyrrole-3-carbonitrile, C 16 H 15 Cl 2 N 3 , (7b), (E)-1-tert-butyl-5-[(pyridin-4-ylmethylene)amino]-1H-pyrrole-3-carbonitrile, C 15 H 16 N 4 , (7c), 1-tert-butyl-5-[(4-chlorobenzyl)amino]-1H-pyrrole-3-carbonitrile, C 16 H 18 ClN 3 , (8a), and 1-tert-butyl-5-[(2,4-dichlorobenzyl)amino]-1H-pyrrole-3-carbonitrile, C 16 H 17 Cl 2 N 3 , (8b), by a two-step synthesis sequence (solvent-free condensation and reduction) starting from 5-amino-1-tert-butyl-1H-pyrrole-3-carbonitrile is described. The syntheses proceed via isolated N-(pyrrol-2-yl)imines, which are also key synthetic intermediates of other valuable compounds. The crystal structures of the reduced compounds showed a reduction in the symmetry compared with the corresponding precursors, viz. Pbcm to P-1 from compound (7a) to (8a) and P2 1 /c to P-1 from compound (7b) to (8b), probably due to a severe change in the molecular conformations, resulting in the loss of planarity observed in the nonreduced compounds. In all of the crystals, the supramolecular assembly is controlled mainly by strong (N,C)-H...N hydrogen bonds. However, in the case of (7a)-(7c), C-H...Cl interactions are strong enough to help in the three-dimensional architecture, as observed in Hirshfeld surface maps.

DERMAL EXPOSURE TO METHYL TERT-BUTYL ETHER (MTBE) AND DIBROMOCHLOROMETHANE (DBCM) WHILE BATHING WITH CONTAMINATED WATER

EPA Science Inventory

The oxygenate methyl tert-butyl ether (MTBE) has been added to gasoline to help meet national ambient air quality standards in those parts of the U.S. that are non-compliant for carbon monoxide. Although MTBE has provided important health benefits in terms of reduced hazardous a...

WATER QUALITY AT FIVE MARINAS IN LAKE TEXOMA AS RELATED TO METHYL TERT-BUTYL ETHER (MTBE)

EPA Science Inventory

Occurrence of methyl tert-butyl ether (MTBE) in five marinas was monitored between June 1999 and November 2000 in Lake Texoma located on the border of Oklahoma and Texas. MTBE is a commonly used gasoline additive and a suspected carcinogen. Lake water was collected at locations i...

Recovery of slaughterhouse Animal Fatty Wastewater Sludge by conversion into Fatty Acid Butyl Esters by acid-catalyzed esterification.

PubMed

Wallis, Christopher; Cerny, Muriel; Lacroux, Eric; Mouloungui, Zéphirin

2017-02-01

Two types of Animal Fatty Wastewater Sludges (AFWS 1 and 2) were analyzed and fully characterized to determine their suitability for conversion into biofuel. AFWS 1 was determined to be unsuitable as it contains 68.8wt.% water and only 32.3wt.% dry material, of which only around 80% is lipids to be converted. AFWS 2 has only 15.7wt.% water and 84.3wt.% dry material of which is assumed to 100% lipids as the protein and ash contents were determined to be negligible. The 4-dodecylbenzenesulfonic acid (DBSA) catalyzed esterification of AFWS with 1-butanol was performed in a novel batch reactor fitted with a drying chimney for the "in situ" removal of water and optimized using a non-conventional Doehlert surface response methodology. The optimized condition was found to be 1.66mol equivalent of 1-butanol (with respect to total fatty acid chains), 10wt.% of DBSA catalyst (with respect to AFWS) at 105°C for 3h. Fatty Acid Butyl Esters (FABEs) were isolated in good yields (95%+) as well as a blend of FABEs with 1-butanol (16%). The two potential biofuels were analyzed in comparison with current and analogous biofuels (FAME based biodiesel, and FABE products made from vegetable oils) and were found to exhibit high cetane numbers and flash point values. Copyright © 2016 Elsevier Ltd. All rights reserved.

Anaerobic Biodegradation Of Methyl tert-Butyl Ether Under Iron-Reducing Conditions In Batch And Continuous-Flow Cultures

EPA Science Inventory

The feasibility of biodegradation of the fuel oxygenate methyl tert-butyl ether (MTBE) under iron-reducing conditions was explored in batch and continuous-flow systems. A porous pot completely-mixed reactor was seeded with diverse cultures and operated under iron-reducing...

CO-OCCURRENCE OF METHYL- TERT-BUTYL ETHER (MTBE) AND BTEX COMPOUNDS AT MARINAS IN A LARGE RESEVOIR

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is released into the environment as one of some gasoline components, not as a pure compound. BTEX compounds (benzene, tolune, ethylbenzene, and xylenes) are major volatile constituents found in gasoline and are water soluble and mobile. This study...

Monitoring of BHT-quinone and BHT-CHO in the gas of capsules of Asclepias physocarpa.

PubMed

Ma, Bing-Ji; Peng, Hua; Liu, Ji-Kai

2006-01-01

Three volatile components, namely benzoic acid ethyl ester (1), 2,6-di-tert-butyl-p-benzoquinone (BHT-quinone) (2), and 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO) (3), were detected from the gas in the capsules of Asclepias physocarpa by means of GC/MS analysis. BHT-quinone and BHT-CHO as organic pollutants are the degradation products of the antioxidant 2,6-di-tert-butyl-4-methylphenol (BHT). Ground water, lake water and/or rain water are a source of BHT metabolites in the plant Asclepias physocarpa.

Salvianic acid A sodium protects HUVEC cells against tert-butyl hydroperoxide induced oxidative injury via mitochondria-dependent pathway.

PubMed

Jia, Dan; Li, Tian; Chen, Xiaofei; Ding, Xuan; Chai, Yifeng; Chen, Alex F; Zhu, Zhenyu; Zhang, Chuan

2018-01-05

Salvianic acid A (Danshensu) is a major water-soluble component extracted from Salvia miltiorrhiza (Danshen), which has been widely used in clinic in China for treatment of cardiovascular diseases (CVDs). This study aimed to investigate the protective effects of salvianic acid A sodium (SAAS) against tert-butyl hydroperoxide (t-BHP) induced human umbilical vein endothelial cell (HUVEC) oxidative injury and the underlying molecular mechanisms. In the antioxidant activity-assessing model, SAAS pretreatment significantly ameliorated the cell growth inhibition and apoptosis induced by t-BHP. An ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) based-metabolic profiling was developed to investigate the metabolic changes of HUVEC cells in response to t-BHP and SAAS. The results revealed that t-BHP injury upregulated 13 metabolites mainly involved in tryptophan metabolism and phenylalanine metabolism which were highly correlated with mitochondrial function and oxidative stress, and 50 μM SAAS pretreatment effectively reversed these metabolic changes. Further biomedical research indicated that SAAS pretreatment reduced the t-BHP induced increase of lactate dehydrogenase (LDH), intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and mitochondrial membrane potential (MMP), and the decrease of key antioxidant enzymes through mitochondria antioxidative pathways via JAK2/STAT3 and PI3K/Akt/GSK-3β signalings. Taken together, our results suggested that SAAS may protect HUVEC cells against t-BHP induced oxidative injury via mitochondrial antioxidative defense system. Copyright © 2017 Elsevier B.V. All rights reserved.

N-tert-Butyl-N'-(5,7-dimethyl-1,8-naphthyridin-2-yl)urea.

PubMed

Lüning, U; Kühl, C; Bolte, M

2001-08-01

The title compound, C(15)H(20)N(4)O, has been synthesized as an AADD recognition unit for quadruple hydrogen bonds. All non-H atoms of the molecule apart from two methyl groups of the tert-butyl group lie in a common plane. An intramolecular hydrogen bond is formed connecting two N atoms. In the solid state, the title compound crystallizes as a centrosymmetric dimer connected by N-H...O=C interactions with an N...O distance of 2.824 (2) A.

tert-Butyl 6-amino-5-cyano-2-(2-meth­oxy­eth­yl)nicotinate

PubMed Central

Chen, Yi-Ning; Zhao, Xing-Dong; Deng, Jie; Li, Qin-Geng

2012-01-01

The title compound, C14H19N3O3, was synthesized by the reaction of 3-meth­oxy­propionitrile, tert-butyl bromo­acetate and eth­oxy­methyl­enemalononitrile. In the crystal, N—H⋯O hydrogen bonds link the mol­ecules into chains propagating along the b axis. PMID:22737103

An efficient synthesis of the constrained peptidomimetic 2-oxo-3-(N-9-fluorenyloxycarbonylamino)-1-azabicyclo[4.3.0]nonane-9-carboxylic acid from pyroglutamic acid.

PubMed

Mandal, Pijus Kumar; Kaluarachchi, Kumar K; Ogrin, Douglas; Bott, Simon G; McMurray, John S

2005-11-25

[reaction: see text] Azabicyclo[X.Y.0]alkane amino acids are rigid dipeptide mimetics that are useful tools for structure-activity studies in peptide-based drug discovery. Herein, we report an efficient synthesis of three diastereomers of 9-tert-butoxycarbonyl-2-oxo-3-(N-tert-butoxycarbonylamino)-1-azabicyclo[4.3.0]nonane (3S,6S,9S, 3S,6R,9R, and 3S,6R,9S). Methyl N-Boc-pyroglutamate is cleaved with vinylmagnesium bromide to produce an acyclic gamma-vinyl ketone. Michael addition of N-diphenylmethyleneglycine tert-butyl ester produces the N-Boc-delta-oxo-alpha,omega-diaminoazelate intermediate, which, on hydrogenloysis, gives the fused ring system. Acidolytic deprotection followed by Fmoc-protection provided building blocks suitable for solid-phase synthesis.

INTERACTION OF METHYL-TERT BUTYL ETHER AND WATER STRESS ON SEED GERMINATION AND SEEDLING GROWTH IN SOIL MICROCOSMS

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is a widespread contaminant in surface and ground water in the United States. Frequently irrigation is used to water fields to germinate planted seeds and sustain plant growth. A likely possibility exists that water used may have some MTBE. Our s...

Analysis of Chemical Signatures of Alkaliphiles using Fatty Acid Methyl Ester Analysis

PubMed Central

Sreenivasulu, Basha; Paramageetham, Chinthala; Sreenivasulu, Dasari; Suman, Bukke; Umamahesh, Katike; Babu, Gundala Prasada

2017-01-01

Background: Fatty acids occur in nearly all living organisms as the important predominant constituents of lipids. While all fatty acids have essentially the same chemical nature, they are an extremely diverse group of compounds. Materials and Methods: To test the hypothesis, fatty acids of alkaliphiles isolates, Bacillus subtilis SVUNM4, Bacillus licheniformis SVUNM8, Bacillus methylotrohicus SVUNM9, and Paenibacillus dendritiformis SVUNM11, were characterized compared using gas chromatography-mass spectrometry (GC-MS) analysis. Results: The content of investigated ten fatty acids, 1, 2-benzenedicarboxylic acid butyl 2-methylpropyl ester, phthalic acid, isobutyl 2-pentyl ester, dibutyl phthalate, cyclotrisiloxane, hexamethyl, cyclotetrasiloxane, octamethyl, dodecamethyl, heptasiloxane 1,1,3,3,5,5,7,7,9,9,11,11,13,13-etradecamethyl, 7,15-dihydroxydehydroabietic acid, methyl ester, di (trimethylsilyl) ether, hentriacontane, 2-thiopheneacetic acid, undec-2-enyl ester, obviously varied among four species, suggesting each species has its own fatty acid pattern. Conclusions: These findings demonstrated that GC-MS-based fatty acid profiling analysis provides the reliable platform to classify these four species, which is helpful for ensuring their biotechnological interest and novel chemotaxonomic. PMID:28717333

Treatment Of Groundwater Contaminated With PAHs, Gasoline Hydrocarbons, And Methyl Tert-Butyl Ether In A Laboratory Biomass-Retaining Bioreactor

EPA Science Inventory

In this study, we investigated the treatability of co-mingled groundwater contaminated with polycyclic aromatic hydrocarbons (PAHs), gasoline hydrocarbons, and methyl tert-butyl ether (MtBE) using an ex-situ aerobic biotreatment system. The PAHs of interest were nap...

Spectroscopic investigation of H atom transfer in a gas-phase dissociation reaction: McLafferty rearrangement of model gas-phase peptide ions.

PubMed

Van Stipdonk, Michael J; Kerstetter, Dale R; Leavitt, Christopher M; Groenewold, Gary S; Steill, Jeffrey; Oomens, Jos

2008-06-14

Wavelength-selective infrared multiple-photon photodissociation (WS-IRMPD) was used to study isotopically-labeled ions generated by McLafferty rearrangement of nicotinyl-glycine-tert-butyl ester and betaine-glycine-tert-butyl ester. The tert-butyl esters were incubated in a mixture of D(2)O and CH(3)OD to induce solution-phase hydrogen-deuterium exchange and then converted to gas-phase ions using electrospray ionization. McLafferty rearrangement was used to generate the free-acid forms of the respective model peptides through transfer of an H atom and elimination of butene. The specific aim was to use vibrational spectra generated by WS-IRMPD to determine whether the H atom remains at the acid group, or migrates to one or more of the other exchangeable sites. Comparison of the IRMPD results in the region from 1200-1900 cm(-1) to theoretical spectra for different isotopically-labeled isomers clearly shows that the H atom is situated at the C-terminal acid group and migration to amide positions is negligible on the time scale of the experiment. The results of this study suggest that use of the McLafferty rearrangement for peptide esters could be an effective approach for generation of H-atom isotope tracers, in situ, for subsequent investigation of intramolecular proton migration during peptide fragmentation studies.

Overview of technologies for removal of methyl tert-butyl ether (MTBE) from water.

PubMed

Levchuk, Irina; Bhatnagar, Amit; Sillanpää, Mika

2014-04-01

Wide use of methyl tert-butyl ether (MTBE) as fuel oxygenates leads to worldwide environment contamination with this compound basically due to fuel leaks from storage or pipelines. Presence of MTBE in drinking water is of high environmental and social concern. Existing methods for MTBE removal from water have a number of limitations which can be possibly overcome in the future with use of emerging technologies. This work aims to provide an updated overview of recent developments in technologies for MTBE removal from water. Copyright © 2014. Published by Elsevier B.V.

Di-tert-butyl­chlorido(N,N-dibenzyl­dithio­carbamato)tin(IV)

PubMed Central

Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R. T.

2011-01-01

The SnIV atom in the title diorganotin dithio­carbamate, [Sn(C4H9)2(C15H14NS2)Cl], is penta­coordinated by an asymmetrically coordinating dithio­carbamate ligand, a Cl atom and two C atoms of the Sn-bound tert-butyl groups. The resulting C2ClS2 donor set defines a coordination geometry inter­mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. PMID:21522304

5,11,17,23-Tetra-tert-butyl-25,26,27,28-tetra­methoxy­calix[4]arene dichloro­methane hemisolvate

PubMed Central

Fischer, Conrad; Gruber, Tobias; Seichter, Wilhelm; Schindler, Diana; Weber, Edwin

2008-01-01

In the title compound, C48H64O4·0.5CH2Cl2, both crystallographically independent calixarene mol­ecules display a partial cone conformation. Their crystal packing is stabilized by C—H⋯π contacts involving the meth­oxy groups. The solvent mol­ecule is located inter­stitially between two calixarene units with C—H⋯Cl contacts to meth­oxy and tert-butyl groups. One tert-butyl residue of each calixarene mol­ecule is disordered over two positions (occupancies 0.60/0.40 and 0.63/0.37), resulting in bond distances that deviate from ideal values. The tetra­mer calixarene mol­ecules present models with approximate non-crystallographic Cs symmetry. PMID:21202066

Determination of selected fate and aquatic toxicity characteristics of acrylic acid and a series of acrylic esters.

PubMed

Staples, C A; Murphy, S R; McLaughlin, J E; Leung, H W; Cascieri, T C; Farr, C H

2000-01-01

Acrylic acid, methyl acrylate, ethyl acrylate, and butyl acrylate are commercially important and widely used materials. This paper reports the results of a series of fate and aquatic toxicity studies. The mobility in soil of acrylic acid and its esters ranged from 'medium' to 'very high'. Calculated bioconcentration factors ranged from 1 to 37, suggesting a low bioconcentration potential. Acrylic acid and methyl acrylate showed limited biodegradability in the five day biochemical oxygen demand (BOD5) test, while ethyl acrylate and butyl acrylate were degraded easily (77% and 56%, respectively). Using the OECD method 301D 28-d closed bottle test, degradability for acrylic acid was 81% at 28 days, while the acrylic esters ranged from 57% to 60%. Acrylic acid degraded rapidly to carbon dioxide in soil (t1/2 < 1 day). Toxicity tests were conducted using freshwater and marine fish, invertebrates, and algae. Acrylic acid effect concentrations for fish and invertebrates ranged from 27 to 236 mg/l. Effect concentrations (LC50 or EC50) for fish and invertebrates using methyl acrylate, ethyl acrylate, and butyl acrylate ranged from 1.1 to 8.2 mg/l. The chronic MATC for acrylic acid with Daphnia magna was 27 mg/l based on length and young produced per adult reproduction day and for ethyl acrylate was 0.29 mg/l based on both the reproductive and growth endpoints. Overall these studies show that acrylic acid and the acrylic esters studied can rapidly biodegrade, have a low potential for persistence or bioaccumulation in the environment, and have low to moderate toxicity.

Effect of benzene, toluene, ethylbenzene, and p-xylene (BTEX) mixture on biodegradation of methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA) by pure culture UC1.

PubMed

Pruden, Amy; Suidan, Makram

2004-08-01

The effect of a BTEX mixture on the biodegradation of methyl tert-butyl ether (MTBE) and its degradation intermediate, tert-butyl alcohol (TBA) was investigated in the pure bacterial culture UC1, which has been identified to be a strain of the known MTBE-degrader PM1 based on greater than 99% 16S rDNA similarity. Several degradation studies were carried out on UC1 at three initial concentration levels of MTBE or TBA: 6-7; 15-17; and 40-45 mg/l, both with and without BTEX present cumulatively at about half of the MTBE or TBA molar mass in the system. The BTEX mixture was observed not to affect either the rate or the degradation lag period of MTBE or TBA degradation, except that the TBA degradation rate actually increased when BTEX was present initially in the highest concentration studies. When serving as the sole substrate, the MTBE degradation rate ranged from 48 +/- 1.2 to 200 +/- 7.0 mg(MTBE)/g(dw) h, and the TBA degradation rate from 140 +/- 18 to 530 +/- 70 mg(TBA)/g(dw) h. When present with BTEX, MTBE and TBA rates ranged from 46 +/- 2.2 to 210 +/- 14 and 170 +/- 28 to 780 +/- 43 mg(TBA)/g(dw) h, respectively. In studies where varying concentrations of TBA were present with 5 mg/l MTBE, both compounds were degraded simultaneously with no obvious preference for either substrate. In the highest concentration study of TBA with 5 mg/l MTBE, BTEX was also observed to increase the ultimate rate of TBA degradation. In addition to exploring the affect of BTEX, this study also provides general insight into the metabolism of MTBE and TBA by pure culture UC1.

Design and Control of Glycerol-tert-Butyl Alcohol Etherification Process

PubMed Central

Vlad, Elena; Bozga, Grigore

2012-01-01

Design, economics, and plantwide control of a glycerol-tert-butyl alcohol (TBA) etherification plant are presented. The reaction takes place in liquid phase, in a plug flow reactor, using Amberlyst 15 as a catalyst. The products' separation is achieved by two distillation columns where high-purity ethers are obtained and a section involving extractive distillation with 1,4-butanediol as solvent, which separates TBA from the TBA/water azeotrope. Details of design performed in AspenPlus and an economic evaluation of the process are given. Three plantwide control structures are examined using a mass balance model of the plant. The preferred control structure fixes the fresh glycerol flow rate and the ratio glycerol + monoether : TBA at reactor-inlet. The stability and robustness in the operation are checked by rigorous dynamic simulation in AspenDynamics. PMID:23365512

Unexpected complexes from meta-phenylene bis(tert-butyl nitroxides) and gadolinium(III) 1,1,1,5,5,5-hexafluoropentane-2,4-dionate

NASA Astrophysics Data System (ADS)

Sekine, Hiroyasu; Ishida, Takayuki

2018-01-01

Coordination reaction of the stable ground triplet biradical biphenyl-3,5-diyl bis(tert-butyl nitroxide) and [Gd(hfac)3(H2O)2] unexpectedly gave complexes containing a dimerized diamagnetic ligand via a [3+3] cycloaddition of the benzene rings (hfac = 1,1,1,5,5,5-hexafluoropentane-2,4-dionate). To avoid such dimerization, we introduced a bulkier substituent into the ligand; namely, a new ground triplet biradical 5-mesityl-1,3-phenylene bis(tert-butyl nitroxide) was applied to this complexation scheme. However, an unexpected complex was again obtained in a different way, and the magnetic study revealed that the novel ligand involved was diamagnetic. The crystallographic analysis of the product clarified isomerization from the paramagnetic ligand to a diamagnetic N-tert-butylaminoquinone imine N-oxide ligand as a result of disproportionation from two open-shell nitroxide groups to closed-shell groups, an amine and a nitrone. The present paper reports the first structural evidence for a diamagnetic isomer of m-phenylene-bridged bisnitroxde compounds.

CONCENTRATIONS, SOURCES, AND FATE OF THE GASOLINE OXYGENATE METHYL TERT-BUTYL ETHER (MTBE) IN A MULTIPLE-USE LAKE. (R826282)

EPA Science Inventory

Discovery of the fuel additive methyl tert-butyl ether (MTBE) in
drinking water supplies is of concern to public health officials, water
suppliers, and the public. Despite recent policy decisions, few published
studies exist on the concentrations, sources, a...

Brucine diol-copper-catalyzed asymmetric synthesis of endo-pyrrolidines: the mechanistic dichotomy of imino esters.

PubMed

Li, Jian-Yuan; Kim, Hun Young; Oh, Kyungsoo

2015-03-06

Enantio- and diastereodivergent approaches to pyrrolidines are described by using catalyst- and substrate-controlled reaction pathways. A concerted endo-selective [3 + 2]-cycloaddition pathway is developed for the reaction of methyl imino ester, whereas endo-pyrrolidines with an opposite absolute stereochemical outcome are prepared by using the stepwise reaction pathway of tert-butyl imino ester. The development of catalyst- and substrate-controlled stereodivergent approaches highlights the inherent substrate-catalyst interactions in the [3 + 2]-cycloaddition reactions of metalated azomethine ylides.

Intriguing Morphology Evolution from Noncrosslinked Poly(tert-butyl acrylate) Seeds with Polar Functional Groups in Soap-Free Emulsion Polymerization of Styrene.

PubMed

Wang, Lu; Pan, Mingwang; Song, Shaofeng; Zhu, Lei; Yuan, Jinfeng; Liu, Gang

2016-08-09

Herein, we demonstrate a facile approach to prepare anisotropic poly(tert-butyl acrylate)/polystyrene (PtBA/PS) composite particles with controllable morphologies by soap-free seeded emulsion polymerization (SSEP). In the first step, noncrosslinked PtBA seeds with self-stabilizing polar functional groups (e.g., ester groups and radicals) are synthesized by soap-free emulsion polymerization. During the subsequent SSEP of styrene (St), PS bulges are nucleated on the PtBA seeds due to the microphase separation confined in the latex particles. The morphology evolution of PtBA/PS composite particles is tailored by varying the monomer/seed feed ratio, polymerization time, and polymerization temperature. Many intriguing morphologies, including hamburger-like, litchi-like, mushroom-like, strawberry-like, bowl-like, and snowman-like, have been acquired for PtBA/PS composite particles. The polar groups on the PtBA seed surface greatly influence the formation and further merging of PS/St bulges during the polymerization. A possible formation mechanism is proposed on the basis of experimental results. These complex composite particles are promising for applications in superhydrophobic coatings.

Expression of an alkane monooxygenase (alkB) gene and methyl tert-butyl ether co-metabolic oxidation in Pseudomonas citronellolis.

PubMed

Bravo, Ana Luisa; Sigala, Juan Carlos; Le Borgne, Sylvie; Morales, Marcia

2015-04-01

Pseudomonas citronellolis UAM-Ps1 co-metabolically transforms methyl tert-butyl ether (MTBE) to tert-butyl alcohol with n-pentane (2.6 mM), n-octane (1.5 mM) or dicyclopropylketone (DCPK) (4.4 mM), a gratuitous inducer of alkane hydroxylase (AlkB) activity. The reverse transcription quantitative real-time PCR was used to quantify the alkane monooxygenase (alkB) gene expression. The alkB gene was expressed in the presence of n-alkanes and DCPK and MTBE oxidation occurred only in cultures when alkB was transcribed. A correlation between the number of alkB transcripts and MTBE consumption was found (ΜΤΒΕ consumption in μmol = 1.44e(-13) x DNA copies, R(2) = 0.99) when MTBE (0.84 mM) was added. Furthermore, alkB was cloned and expressed into Escherichia coli and the recombinant AlkB had a molecular weight of 42 kDa. This is the first report where the expression of alkB is related to the co-metabolic oxidation of MTBE.

Antioxidant capacity of BO-653, 2,3-dihydro-5-hydroxy-4,6-di-tert-butyl-2,2-dipentylbenzofuran, and uric acid as evaluated by ORAC method and inhibition of lipid peroxidation.

PubMed

Niki, Etsuo; Fukuhara, Akiko; Omata, Yo; Saito, Yoshiro; Yoshida, Yasukazu

2008-04-01

The role of radical-scavenging antioxidant against oxidative stress has received much attention. The antioxidant capacity has been assessed by various methods. Above all, oxygen radical absorbance capacity (ORAC) has been frequently employed [Prior et.al., J. Agric. Food Chem.2005, 53, 4290]. In the present study, the antioxidant capacity of 2,3-dihydro-5-hydroxy-4,6-di-tert-butyl-2,2-dipentylbenzofuran (BO-653) and uric acid was assessed by ORAC method using pyranine as a reference probe and compared with that against lipid peroxidation of human plasma. It was found that BO-653 was assessed to be much less potent than uric acid by ORAC method, whereas BO-653 exerted much higher antioxidant activity than uric acid against plasma lipid peroxidation. The reason for such discrepancy is discussed. The results suggest that ORAC method is suitable for the assessment of free radical scavenging capacity, but not for the assessment of antioxidant capacity against lipid peroxidation in plasma.

(N-Benzyl-N-ethyl­dithio­carbamato)di-tert-butyl­chloridotin(IV)

PubMed Central

Abdul Muthalib, Amirah Faizah; Baba, Ibrahim; Mohamed Tahir, Mohamed Ibrahim; Tiekink, Edward R. T.

2011-01-01

The SnIV atom in the title diorganotin dithio­carbamate, [Sn(C4H9)2Cl(C10H12NS2)], is penta­coordinated by an asymmetrically coordinating dithio­carbamate ligand, a Cl and two C atoms of the Sn-bound tert-butyl groups. The resulting C2ClS2 donor set defines a coordination geometry inter­mediate between square pyramidal and trigonal bipyramidal with a slight tendency towards the former. In the crystal structure, C—H⋯π contacts link centrosymmetrically related mol­ecules into dimeric aggregates. PMID:21522295

Antioxidants Inhibit Formation of 3-Monochloropropane-1,2-diol Esters in Model Reactions.

PubMed

Li, Chang; Jia, Hanbing; Shen, Mingyue; Wang, Yuting; Nie, Shaoping; Chen, Yi; Zhou, Yongqiang; Wang, Yuanxing; Xie, Mingyong

2015-11-11

The capacities of six antioxidants to inhibit the formation of 3-monochloropropane-1,2 diol (3-MCPD) esters were examined in this study. Inhibitory capacities of the antioxidants were investigated both in chemical models containing the precursors (tripalmitoyl glycerol, 1,2-dipalmitoyl-sn-glycerol, monopalmitoyl glycerol, and sodium chloride) of 3-MCPD esters and in oil models (rapeseed oil and sodium chloride). Six antioxidants, butylated hydroxytoluene (BHT), butylated hydroxy anisole (BHA), tert-butyl hydroquinone (TBHQ), propyl gallate (PG), L-ascorbyl palmitate (AP), and α-tocopherol (VE), were found to exhibit inhibiting capacities on 3-MCPD ester formation both in chemical models and in oil models. TBHQ provided the highest inhibitory capacity both in chemical models and in oil models; 44% of 3-MCPD ester formation was inhibited in the presence of TBHQ (66 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min, followed by PG and AP. BHT, BHA, and VE appeared to have weaker inhibitory abilities in both models. VE exhibited the lowest inhibition rate; 22% of 3-MCPD esters were inhibited in the presence of VE (172 mg/kg of oil) after heating of rapeseed oil at 230 °C for 30 min. In addition, the inhibition rates of PG and VE decreased dramatically with an increase in temperature or heating time. The results suggested that some antioxidants, such as TBHQ, PG, and AP, could be the potential inhibitors of 3-MCPD esters in practice.

Microbial community composition during anaerobic mineralization of tert-butyl alcohol (TBA) in fuel-contaminated aquifer material.

PubMed

Wei, Na; Finneran, Kevin T

2011-04-01

Anaerobic mineralization of tert-butyl alcohol (TBA) and methyl tert-butyl ether (MTBE) were studied in sediment incubations prepared with fuel-contaminated aquifer material. Microbial community compositions in all incubations were characterized by amplified ribosomal DNA restriction analysis (ARDRA). The aquifer material mineralized 42.3±9.9% of [U-(14)C]-TBA to 14CO2 without electron acceptor amendment. Fe(III), sulfate, and Fe(III) plus anthraquinone-2,6-disulfonate addition also promoted U-[14C]-TBA mineralization at levels similar to those of the unamended controls. Nitrate actually inhibited TBA mineralization relative to unamended controls. In contrast to TBA, [U-(14)C]-MTBE was not significantly mineralized in 400 days regardless of electron acceptor amendment. Microbial community analysis indicated that the abundance of one dominant clone group correlated closely with anaerobic TBA mineralization. The clone was phylogenetically distinct from known aerobic TBA-degrading microorganisms, Fe(III)- or sulfate-reducing bacteria. It was most closely associated with organisms belonging to the alphaproteobacteria. Microbial communities were different in MTBE and TBA amended incubations. Shannon indices and Simpson indices (statistical community comparison tools) both demonstrated that microbial community diversity decreased in incubations actively mineralizing TBA, with distinct "dominant" clones developing. These data contribute to our understanding of anaerobic microbial transformation of fuel oxygenates in contaminated aquifer material and the organisms that may catalyze the reactions.

Sequestering ability of butylated hydroxytoluene, propyl gallate, resveratrol, and vitamins C and E against ABTS, DPPH, and hydroxyl free radicals in chemical and biological systems.

PubMed

Soares, Daniele G; Andreazza, Ana C; Salvador, Mirian

2003-02-12

The antioxidant capacity of butylated hydroxytoluene (BHT; 2,6-di-tert-butyl-p-cresol), propyl gallate (3,4,5-trihydroxybenzoic acid n-propyl ester), resveratrol (trans-3,4',5-trihydroxystilbene), and vitamins C (l-ascorbic acid) and E [(+)-alpha-tocopherol] was studied in chemical and biological systems. The chemical assays evaluated the capacity of these antioxidants to sequester 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS.) and 1,1 diphenyl-2-picrylhydrazyl (DPPH.). A new colorimetric method to determine hydroxyl radical scavenging is also described. The biological tests use the eucaryotic cells of Saccharomyces cerevisiae treated with the antioxidants in the presence of the stressing agents apomorphine, hydrogen peroxide, and paraquat dichloride (methylviologen; 1,1'-dimethyl-4,4'-bipyridinium dichloride). The results in chemical systems showed that all of the antioxidants were able to significantly inhibit the oxidation of beta-carotene by hydroxyl free radicals. The assays in yeast showed that the antioxidant activity of the tested compounds depended on the stressing agent used and the mechanism of action of the antioxidant.

Azobenzene versus 3,3',5,5'-tetra-tert-butyl-azobenzene (TBA) at Au(111): characterizing the role of spacer groups.

PubMed

McNellis, Erik R; Bronner, Christopher; Meyer, Jörg; Weinelt, Martin; Tegeder, Petra; Reuter, Karsten

2010-06-28

We present large-scale density-functional theory (DFT) calculations and temperature programmed desorption measurements to characterize the structural, energetic and vibrational properties of the functionalized molecular switch 3,3',5,5'-tetra-tert-butyl-azobenzene (TBA) adsorbed at Au(111). Particular emphasis is placed on exploring the accuracy of the semi-empirical dispersion correction approach to semi-local DFT (DFT-D) in accounting for the substantial van der Waals component in the surface bonding. In line with previous findings for benzene and pure azobenzene at coinage metal surfaces, DFT-D significantly overbinds the molecule, but seems to yield an accurate adsorption geometry as far as can be judged from the experimental data. Comparing the trans adsorption geometry of TBA and azobenzene at Au(111) reveals a remarkable insensitivity of the structural and vibrational properties of the -N[double bond, length as m-dash]N- moiety. This questions the established view of the role of the bulky tert-butyl-spacer groups for the switching of TBA in terms of a mere geometric decoupling of the photochemically active diazo-bridge from the gold substrate.

Enhanced cometabolic degradation of methyl tert-butyl ether by a Pseudomonas sp. strain grown on n-pentane

NASA Astrophysics Data System (ADS)

Li, S. S.; Wang, S.; Yan, W.

2016-08-01

When methyl tert-butyl ether (MTBE) is added as oxygenates it increases the octane number and decreases the release of nitric oxide from the incomplete combustion of reformulated gasoline. The extensive use of MTBE allowed it to be detectable as a pollutant in both ground-level and underground water worldwide. The present study focuses on the isolation and characterization of MTB-degrading microorganisms by cometabolism based on the results of growth on different carbon sources. It also focuses on the kinetic analysis and the continuous degradation of MTBE. A bacterial strain WL1 that can grow on both n-alkanes (C5-C8) and aromatics was isolated and named Pseudomonas sp. WL1 according to the 16S rDNA sequencing analysis. Strain WL1 could cometabolically degrade MTBE in the presence of n-alkanes with a desirable degradation rate. Diverse n-alkanes with different lengths of carbon chains showed significant influence on the degradation rate of MTBE and accumulation of tert-butyl alcohol (TBA). When strain WL1 cometabolically degraded MTBE in the presence of n-pentane, higher MTBE-degrading rate and lower TBA-accumulation were observed (Vmax = 38.1 nmol/min/mgprotei, Ks = 6.8 mmol/L). In the continuous degrading experiment, the removal efficiency of MTBE by Pseudomonas sp. WL1 did not show any obvious decrease after five subsequent additions.

Environmental behavior and fate of methyl tert-butyl ether (MTBE)

USGS Publications Warehouse

Squillace, Paul J.; Pankow, James F.; Korte, Nic E.; Zogorski, John S.

1996-01-01

When gasoline that has been oxygenated with methyl tert-butyl ether (MTBE) comes in contact with water, large amounts of MTBE can dissolve; at 25 degrees Celsius the water solubility of MTBE is about 5,000 milligrams per liter for a gasoline that is 10 percent MTBE by weight. In contrast, for a nonoxygenated gasoline, the total hydrocarbon solubility in water is typically about 120 milligrams per liter. MTBE sorbs only weakly to soil and aquifer materials; therefore, sorption will not significantly retard MTBE's transport by ground water. In addition, MTBE generally resists degradation in ground water. The half-life of MTBE in the atmosphere can be as short as 3 days in a regional airshed. MTBE in the air tends to partition into atmospheric water, including precipitation. However, washout of gas-phase MTBE by precipitation would not, by itself, greatly alter the gas-phase concentration of the compound in the air. The partitioning of MTBE to precipitation is nevertheless strong enough to allow for up to 3 micrograms per liter or more inputs of MTBE to surface and ground water.

Methyl tert-butyl ether (MTBE) in finished drinking water in Germany.

PubMed

Kolb, Axel; Püttmann, Wilhelm

2006-03-01

In the present study 83 finished drinking water samples from 50 cities in Germany were analyzed for methyl tert-butyl ether (MTBE) content with a detection limit of 10 ng/L. The detection frequency was 46% and the concentrations ranged between 17 and 712 ng/L. Highest concentrations were found in the community water systems (CWSs) of Leuna and Spergau in Saxony-Anhalt. These CWSs are supplied with water possibly affected by MTBE contaminated groundwater. MTBE was detected at concentrations lower than 100 ng/L in drinking water supplied by CWSs using bank filtered water from Rhine and Main Rivers. The results from Leuna and Spergau show that large groundwater contaminations in the vicinity of CWSs pose the highest risk for MTBE contamination in drinking water. CWSs using bank filtered water from Rhine and Main Rivers are susceptible to low MTBE contaminations in finished drinking water. All measured MTBE concentrations were below proposed limit values for drinking water.

Synthesis and low temperature characterization of iso-oleic ester derivatives

USDA-ARS?s Scientific Manuscript database

Three new iso-oleic ester derivatives (i.e., isopropyl esters (IOA-iPrE), n-butyl esters (IOA-n-BuE), and 2-ethylhexyl esters (IOA-2-EHE)) were synthesized from iso-oleic acid (IOA) using a standard esterification method. These esterified alcohols were chosen because of their bulky and branched-cha...

Amide and Ester-Functionalized Humic Acid for Fuel Combustion Enhancement

NASA Astrophysics Data System (ADS)

Riggs, Mark

Humic acid is a class of naturally occurring molecules composed of large sheet-like regions of cyclic aromatic hydrocarbon networks with surface and edge functional groups including phenols, carboxylic acids, and epoxides. These naturally occurring molecules are found in brown coal deposits near lignite formations. Humic acid has gained attention from the scientific community as a precursor for graphene. Graphene is a 2-dimensional honeycomb structure of fully unsaturated carbon atoms that has exceptional material properties and inherent aromaticity. Graphene's incredible properties are matched by the difficulty associated with reproducibly manufacturing it on a large scale. This issue has limited the use of graphene for commercial applications. The polar functional groups of humic acid contribute to the hydrophilic nature of the molecule, limiting its miscibility in any alkyl-based solvent. Surfactants containing long alkyl chains can affect the miscibility of the molecule in an organic solvent. Surfactants are often difficult to remove from the system. It is theorized that alkylation of the functional sites of humic acid can affect the hydrophilic nature of the molecule, and effectively enable its dispersion into organic solvents without simultaneous incorporation of surfactants. This dissertation investigated the amidation and esterification of humic acid molecules extracted from leonardite. The resulting change in the modified humic acid dispersibility in organic solvents and its potential usage as a fuel additive were evaluated. Butyl, hexyl, octyl, and decyl amide-modified and ester-modified humic acids were synthesized. These products were characterized to confirm successful chemical reaction through thermogravimetric analysis, Fourier-transform infrared spectroscopy, and scanning electron microscopy. The decyl-modified humic acids remained suspended in kerosene mixtures for longer than 1 week. Other organo-humic acids showed varying degrees of flocculation

Demethylation of 5,n-di-tert-butyl-8,n-dimethoxy[2.n]metacyclophane-1-ynes with BBr3 to afford novel [n]benzofuranophanes

NASA Astrophysics Data System (ADS)

Akther, Thamina; Islam, Md Monarul; Matsumoto, Taisuke; Tanaka, Junji; Feng, Xing; Redshaw, Carl; Yamato, Takehiko

2016-10-01

Novel [n]benzofuranophanes (n = 8 & 10) 2a-b have been prepared by successive intramolecular cyclization from 5,19-di-tert-butyl-8,22-dimethoxy[n]metacyclophane-1-yne (syn-1a-b) by treatment with BBr3 in CH2Cl2 at room temperature for 8h. [2.n]Benzofuranophanes 2a-b were also obtained by treatment of 1,2-di-endo-bromo-5,19-di-tert-butyl-8,22-dimethoxy[n]metacyclophane (meso-3a-b) with BBr3 in CH2Cl2 by using the same reaction conditions. 1H NMR spectra of 2a-b reveals the formation of intramolecular hydrogen bonding between hydroxyl proton with the oxygen of the furan moiety and X-ray analysis shows that the lengths between H (OH) and O (furan) are 1.981 and 1.823 Å̊, respectively. The conformation of [8]benzofuranophane 2a in solution is rigid with restricted rotation around the diaryl linkage rather than [10]benzofuranophane 2b because of weak intramolecular hydrogen bonding and the short length of the cross-linking chain.

Comparative transcriptome analysis of Methylibium petroleiphilum PM1 exposed to the fuel oxygenates methyl tert-butyl ether and ethanol.

PubMed

Hristova, Krassimira R; Schmidt, Radomir; Chakicherla, Anu Y; Legler, Tina C; Wu, Janice; Chain, Patrick S; Scow, Kate M; Kane, Staci R

2007-11-01

High-density whole-genome cDNA microarrays were used to investigate substrate-dependent gene expression of Methylibium petroleiphilum PM1, one of the best-characterized aerobic methyl tert-butyl ether (MTBE)-degrading bacteria. Differential gene expression profiling was conducted with PM1 grown on MTBE and ethanol as sole carbon sources. Based on microarray high scores and protein similarity analysis, an MTBE regulon located on the megaplasmid was identified for further investigation. Putative functions for enzymes encoded in this regulon are described with relevance to the predicted MTBE degradation pathway. A new unique dioxygenase enzyme system that carries out the hydroxylation of tert-butyl alcohol to 2-methyl-2-hydroxy-1-propanol in M. petroleiphilum PM1 was discovered. Hypotheses regarding the acquisition and evolution of MTBE genes as well as the involvement of IS elements in these complex processes were formulated. The pathways for toluene, phenol, and alkane oxidation via toluene monooxygenase, phenol hydroxylase, and propane monooxygenase, respectively, were upregulated in MTBE-grown cells compared to ethanol-grown cells. Four out of nine putative cyclohexanone monooxygenases were also upregulated in MTBE-grown cells. The expression data allowed prediction of several hitherto-unknown enzymes of the upper MTBE degradation pathway in M. petroleiphilum PM1 and aided our understanding of the regulation of metabolic processes that may occur in response to pollutant mixtures and perturbations in the environment.

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.

Occurrence of fatty acid short-chain-alkyl esters in fruits of Celastraceae plants.

PubMed

Sidorov, Roman A; Zhukov, Anatoly V; Pchelkin, Vasily P; Vereshchagin, Andrei G; Tsydendambaev, Vladimir D

2013-06-01

Small amounts of a mixture of fatty acid short-chain-alkyl esters (FASCAEs) were obtained from the fruits of twelve plant species of Celastraceae family, and in five of them the FASCAEs were present not only in the arils but also in the seeds. These mixtures contained 32 individual FASCAE species, which formed four separate fractions, viz. FA methyl, ethyl, isopropyl, and butyl esters (FAMEs, FAEEs, FAIPEs, and FABEs, resp.). The FASCAE acyl components included the residues of 16 individual C₁₄-C₂₄ saturated, mono-, di-, and trienoic FAs. Linoleic, oleic, and palmitic acids, and, in some cases, also α-linolenic acid predominated in FAMEs and FAEEs, while myristic acid was predominant in FAIPEs. It can be suggested that, in the fruit arils of some plant species, FAMEs and FAEEs were formed at the expense of a same FA pool characteristic of a given species and were strongly different from FAIPEs and FABEs esters regarding the mechanism of their biosynthesis. However, as a whole, the qualitative and quantitative composition of various FASCAE fractions, as well as their FA composition, varied considerably depending on various factors. Therefore, separate FASCAE fractions seem to be synthesized from different FA pools other than those used for triacylglycerol formation. Copyright © 2013 Verlag Helvetica Chimica Acta AG, Zürich.

The effect of sorbic acid and esters of p-hydroxybenzoic acid on the protonmotive force in Escherichia coli membrane vesicles.

PubMed

Eklund, T

1985-01-01

The effect of three food preservatives, sorbic acid and methyl and butyl esters of p-hydroxybenzoic acid, on the protonmotive force in Escherichia coli membrane vesicles was investigated. Radioactive chemical probes were used to determine the two components of the protonmotive force: delta pH (pH difference) and delta psi (membrane potential). Both types of compound selectively eliminated delta pH across the membrane, while leaving delta psi much less disturbed indicating that transport inhibition by neutralization of the protonmotive force cannot be the only mechanism of action for the food preservatives tested.

Aerobic biodegradation of tert-butyl alcohol (TBA) by psychro- and thermo-tolerant cultures derived from granular activated carbon (GAC).

PubMed

Reinauer, Kimberly M; Zhang, Yang; Yang, Xiaomin; Finneran, Kevin T

2008-04-01

Tert-butyl alcohol (TBA) is a metabolite of methyl tert-butyl ether and is itself possibly a fuel oxygenate. The goals of this study were to enrich and characterize TBA-degrading micro-organism(s) from a granular activated carbon (GAC) unit currently treating TBA. The results reported herein describe the first aerobic, TBA-degrading cultures derived from GAC. Strains KR1 and YZ1 were enriched from a GAC sample in a bicarbonate-buffered freshwater medium. TBA was degraded to 10% of the initial concentration (2-5 mM) within 5 days after initial inoculation and was continuously degraded within 1 day of each re-amendment. Resting cell suspensions mineralized 70 and 60% of the TBA within 24 h for KR1 and YZ1, respectively. Performance optimization with resting cells was conducted to investigate kinetics and the extent of TBA degradation as influenced by oxygen, pH and temperature. The most favorable temperature was 37 degrees C; however, TBA was degraded from 4 to 60 degrees C, indicating that the culture will sufficiently treat groundwater without heating. This is also the first report of psychrotolerant or thermotolerant TBA biodegradation. The pH range for TBA degradation ran from 5.0 to 9.0. Phylogenetic data using a partial 16S rRNA gene sequence (570 bases) suggest that the primary members of KR1 and YZ1 include uncharacterized organisms within the genera Hydrogenophaga, Caulobacter, and Pannonibacter.

Methyl tert-butyl ether biodegradation by microbial consortia obtained from soil samples of gasoline-polluted sites in Mexico.

PubMed

Morales, Marcia; Velázquez, Elia; Jan, Janet; Revah, Sergio; González, Uriel; Razo-Flores, Elías

2004-02-01

Microbial consortia obtained from soil samples of gasoline-polluted sites were individually enriched with pentane, hexane, isooctane and toluene. Cometabolism with methyl tert-butyl ether, (MTBE), gave maximum degradation rates of 49, 12, 32 and 0 mg g(-1)protein h(-1), respectively. MTBE was fully degraded even when pentane was completely depleted with a cometabolic coefficient of 1 mgMTBE mg(-1)pentane. The analysis of 16S rDNA from isolated microorganisms in the pentane-adapted consortia showed that microorganisms could be assigned to Pseudomonas. This is the first work reporting the cometabolic mineralization of MTBE by consortium of this genus.

Melanogenesis-inhibitory saccharide fatty acid esters and other constituents of the fruits of Morinda citrifolia (noni).

PubMed

Akihisa, Toshihiro; Tochizawa, Shun; Takahashi, Nami; Yamamoto, Ayako; Zhang, Jie; Kikuchi, Takashi; Fukatsu, Makoto; Tokuda, Harukuni; Suzuki, Nobutaka

2012-06-01

Five new saccharide fatty acid esters, named nonioside P (3), nonioside Q (4), nonioside R (8), nonioside S (10), and nonioside T (14), and one new succinic acid ester, butyl 2-hydroxysuccinate (=4-butoxy-3-hydroxy-4-oxobutanoic acid) (31), were isolated, along with 26 known compounds, including eight saccharide fatty acid esters, 1, 2, 5, 6, 7, 9, 12, and 13, three hemiterpene glycosides, 15, 17, and 18, six iridoid glycosides, 21-25, and 27, and nine other compounds, 20, 28, 29, and 32-37, from a MeOH extract of the fruit of Morinda citrifolia (noni). Upon evaluation of these and five other glycosidic compounds, 11, 16, 19, 26, and 30, from M. citrifolia fruit extract for their inhibitory activities against melanogenesis in B16 melanoma cells induced with α-melanocyte-stimulating hormone (α-MSH), most of the saccharide fatty acid esters, hemiterpene glycosides, and iridoid glycosides showed inhibitory effects with no or almost no toxicity to the cells. These compounds were further evaluated with respect to their cytotoxic activities against two human cancer cell lines (HL-60 and AZ521) and their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced with 12-O-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. Copyright © 2012 Verlag Helvetica Chimica Acta AG, Zürich.

Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1.

PubMed

Joshi, Geetika; Schmidt, Radomir; Scow, Kate M; Denison, Michael S; Hristova, Krassimira R

2016-09-01

Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds' impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1.

Effect of benzene and ethylbenzene on the transcription of methyl-tert-butyl ether degradation genes of Methylibium petroleiphilum PM1

PubMed Central

Joshi, Geetika; Schmidt, Radomir; Scow, Kate M.; Denison, Michael S.; Hristova, Krassimira R.

2016-01-01

Methyl-tert-butyl ether (MTBE) and its degradation by-product, tert-butyl alcohol (TBA), are widespread contaminants detected frequently in groundwater in California. Since MTBE was used as a fuel oxygenate for almost two decades, leaking underground fuel storage tanks are an important source of contamination. Gasoline components such as BTEX (benzene, toluene, ethylbenzene and xylenes) are often present in mixtures with MTBE and TBA. Investigations of interactions between BTEX and MTBE degradation have not yielded consistent trends, and the molecular mechanisms of BTEX compounds’ impact on MTBE degradation are not well understood. We investigated trends in transcription of biodegradation genes in the MTBE-degrading bacterium, Methylibium petroleiphilum PM1 upon exposure to MTBE, TBA, ethylbenzene and benzene as individual compounds or in mixtures. We designed real-time quantitative PCR assays to target functional genes of strain PM1 and provide evidence for induction of genes mdpA (MTBE monooxygenase), mdpJ (TBA hydroxylase) and bmoA (benzene monooxygenase) in response to MTBE, TBA and benzene, respectively. Delayed induction of mdpA and mdpJ transcription occurred with mixtures of benzene and MTBE or TBA, respectively. bmoA transcription was similar in the presence of MTBE or TBA with benzene as in their absence. Our results also indicate that ethylbenzene, previously proposed as an inhibitor of MTBE degradation in some bacteria, inhibits transcription of mdpA, mdpJ and bmoAgenes in strain PM1. PMID:27450417

Rigid Dipeptide Mimics: Synthesis of Enantiopure 5- and 7-Benzyl and 5,7-Dibenzyl Indolizidinone Amino Acids via Enolization and Alkylation of delta-Oxo alpha,omega-Di-[N-(9-(9-phenylfluorenyl))amino]azelate Esters.

PubMed

Polyak, Felix; Lubell, William D.

1998-08-21

Azabicyclo[X.Y.0]alkane amino acids are tools for constructing mimics of peptide structure and templates for generating combinatorial libraries for drug discovery. Our methodology for synthesizing these conformationally rigid dipeptides has been elaborated such that alkyl groups can be appended onto the heterocycle to generate mimics of peptide backbone and side-chain structure. Inexpensive glutamic acid was employed as chiral educt in a Claisen condensation/ketone alkylation/reductive amination/lactam cyclization sequence that furnished alkyl-branched azabicyclo[4.3.0]alkane amino acid. Enantiopure 5-benzyl-, 7-benzyl-, and 5,7-dibenzylindolizidinone amino acids 2-4 were stereoselectively synthesized via efficient reaction sequences featuring the alkylation of di-tert-butyl alpha,omega-di-[N-(PhF)amino]azelate delta-ketone 5. A variety of alkyl halides were readily added to the enolate of ketone 5 to provide mono- and dialkylated ketones 6 and 7. Hydride additions to 6 and 7, methanesulfonations, and intramolecular S(N)2 displacements by the PhF amine gave 5-alkylprolines that were converted by lactam cyclizations into 7- and 5-benzyl-, as well as 5,7-dibenzyl-2-oxo-3-N-(BOC)amino-1-azabicyclo[4.3.0]nonane-9-carboxylate methyl esters 10, 11, and 14. Epimerization of the alkyl-branched stereocenter via an iminium-enaminium equilibrium proved effective for controlling diastereoselectivity in reductive aminations with 6 and 7 in order to furnish 5-alkylprolines that were similarly converted to 7- benzyl- and 5,7-dibenzylindolizidinone N-(BOC)amino esters 10 and 14. Ester hydrolysis with hydroxide ion and potassium trimethylsilanolate then gave enantiopure indolizidinone amino acids 2-4. Epimerization at C-9 of benzylindolizidinone amino esters was also used to provide alternative diastereomers of 10, 11, and 14. This practical methodology for introducing side-chain groups onto the heterocycle with regioselective and diastereoselective control is designed to enhance

Cultivation of Aquincola tertiaricarbonis L108 on the fuel oxygenate intermediate tert-butyl alcohol induces aerobic anoxygenic photosynthesis at extremely low feeding rates.

PubMed

Rohwerder, Thore; Müller, Roland H; Weichler, M Teresa; Schuster, Judith; Hübschmann, Thomas; Müller, Susann; Harms, Hauke

2013-10-01

Aerobic anoxygenic photosynthesis (AAP) is found in an increasing number of proteobacterial strains thriving in ecosystems ranging from extremely oligotrophic to eutrophic. Here, we have investigated whether the fuel oxygenate-degrading betaproteobacterium Aquincola tertiaricarbonis L108 can use AAP to compensate kinetic limitations at low heterotrophic substrate fluxes. In a fermenter experiment with complete biomass retention and also during chemostat cultivation, strain L108 was challenged with extremely low substrate feeding rates of tert-butyl alcohol (TBA), an intermediate of methyl tert-butyl ether (MTBE). Interestingly, formation of photosynthetic pigments, identified as bacteriochlorophyll a and spirilloxanthin, was only induced in growing cells at TBA feeding rates less than or equal to maintenance requirements observed under energy excess conditions. Growth continued at rates between 0.001 and 0.002 h(-1) even when the TBA feed was decreased to values close to 30 % of this maintenance rate. Partial sequencing of genomic DNA of strain L108 revealed a bacteriochlorophyll synthesis gene cluster (bchFNBHL) and photosynthesis regulator genes (ppsR and ppaA) typically found in AAP and other photosynthetic proteobacteria. The usage of light as auxiliary energy source enabling evolution of efficient degradation pathways for kinetically limited heterotrophic substrates and for lowering the threshold substrate concentration Smin at which growth becomes zero is discussed.

On the competition between weak O-H···F and C-H···F hydrogen bonds, in cooperation with C-H···O contacts, in the difluoromethane – tert-butyl alcohol cluster

PubMed Central

Spada, Lorenzo; Tasinato, Nicola; Bosi, Giulio; Vazart, Fanny; Barone, Vincenzo; Puzzarini, Cristina

2017-01-01

The 1:1 complex of tert-butyl alcohol with difluoromethane has been characterized by means of a joint experimental-computational investigation. Its rotational spectrum has been recorded by using a pulsed-jet Fourier-Transform microwave spectrometer. The experimental work has been guided and supported by accurate quantum-chemical calculations. In particular, the computed potential energy landscape pointed out the formation of three stable isomers. However, the very low interconversion barriers explain why only one isomer, showing one O-H···F and two C-H···O weak hydrogen bonds, has been experimentally characterized. The effect of the H → tert-butyl- group substitution has been analyzed from the comparison to the difluoromethane-water adduct. PMID:28919646

Entanglement Dynamics in Miscible Polyisoprene / Poly(p-tert-butyl styrene) Blends

NASA Astrophysics Data System (ADS)

Watanabe, Hiroshi

2011-03-01

Viscoelastic and dielectric behavior was examined for well entangled, miscible blends of high- M cis-polyisoprene (PI) and poly(p-tert-butyl styrene) (PtBS). The dielectric data of the blends, reflecting the global motion of the PI chains having the type-A dipoles, indicated that PI and PtBS were the fast and slow components therein. At high temperatures T , the blends exhibited two-step entanglement plateau. The high frequency (ω) plateau height was well described by a simple mixing rule of the entanglement length based on the number fraction of the Kuhn segments. At low T , the blend exhibited the Rouse-like power-law behavior of storage and loss moduli, G ' = G ~ω0.5 , in the range of ω where the high- ω plateau was supposed to emerge. This lack of the high- ω plateau was attributed to retardation of the Rouse equilibration of the PI chain over the entanglement length due to the hindrance from the slow PtBS chains: The PI and PtBS chains were equilibrated cooperatively, and the retardation due to PtBS shortened the plateau for PI to a width not resolved experimentally. A simple model for this cooperative equilibration formulated on the basis of the dielectric data described the viscoelastic data surprisingly well.

Unambiguous detection of astaxanthin and astaxanthin fatty acid esters in krill (Euphausia superba Dana).

PubMed

Grynbaum, Marc David; Hentschel, Petra; Putzbach, Karsten; Rehbein, Jens; Krucker, Manfred; Nicholson, Graeme; Albert, Klaus

2005-09-01

HPLC atmospheric pressure chemical ionization (APCI)/MS, GC MS, HPLC diode array detection (DAD), and NMR were used for the identification of astaxanthin and astaxanthin fatty acid esters in krill (Euphausia superba Dana). Matrix solid phase dispersion was applied for the extraction of the carotenoids. This gentle and expeditious extraction technique for solid and viscous samples leads to distinct higher enrichment rates than the conventional liquid-liquid extraction. The chromatographic separation was achieved employing a C30 RP column that allows the separation of shape-constrained geometrical isomers. A methanol/tert-butylmethyl ether/water gradient was applied. (all-E) Astaxanthin and the geometrical isomers were identified by HPLC APCI/MS, by coelution with isomerized authentical standard, by UV spectroscopy (DAD), and three isomers were unambiguously assigned by microcoil NMR spectroscopy. In this method, microcoils are transversally aligned to the magnetic field and have an increased sensitivity compared to the conventional double-saddle Helmholtz coils, thus enabling the measurement on small samples. The carotenol fatty acid esters were saponified enzymatically with Lipase type VII from Candida rugosa. The fatty acids were detected by GC MS after transesterification, but also without previous derivatization by HPLC APCI/MS. C14:0, C16:0, C16:1, C18:1, C20:0, C20:5, and C22:6 were found in astaxanthin monoesters and in astaxanthin diesters. (all-E) Astaxanthin was identified as the main isomer in six fatty acid ester fractions by NMR. Quantitation was carried out by the method of internal standard. (13-cis) Astaxanthin (70 microg/g), 542 microg/g (all-E) astaxanthin, 36 microg/g unidentified astaxanthin isomer, 62 microg/g (9-cis) astaxanthin, and 7842 microg/g astaxanthin fatty acid esters were found.

[Occupational exposure to methyl tert-butyl ether (MTBE) at an oil refinery].

PubMed

Perbellini, L; Pasini, F; Prigioni, P; Rosina, A

2003-01-01

Methyl tert-butyl ether (MTBE) is widely used as an additive to gasoline, to increase oxygen content and reduce tailpipe emission of carbon monoxide. Our research dealt with 37 refinery workers in order to measure their occupational exposure to MTBE during two different seasonal periods. They provided blood and urine samples before and after a work shift during which they wore an active charcoal sampler for solvents. All samples were analysed by a gas-chromatograph equipped with a mass spectrometer detector. The concentration in air of MTBE was very low (median: 25 micrograms/m3 in spring and 5 micrograms/m3 in autumn). The blood and urine concentrations of MTBE at the end of the work shift were higher than those found before the shift. The increment in biological samples confirmed a small intake of MTBE by refinery workers: the biological monitoring of occupational exposure to this solvent yielded reliable results. Blood and urinary concentrations of MTBE obtained from workers split in relation to their smoking habit did not give a statistic significance to say that cigarette smoke is not a confusion factor in monitoring exposure to MTBE.

METHYL TERT-BUTYLETHER-WATER INTERACTION

EPA Science Inventory

Methyl tert-butyl ether (MTBE) is a well-known environmental contaminant owing to its high solubility in water. Since the early 1990s, MTBE has been added to gasoline to improve air quality in some metropolitan areas of the United States. Improved air quality was, however, achiev...

Biosynthesis of tert-butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate by carbonyl reductase from Rhodosporidium toruloides in mono and biphasic media.

PubMed

Liu, Zhi-Qiang; Wu, Lin; Zheng, Ling; Wang, Wen-Zhong; Zhang, Xiao-Jian; Jin, Li-Qun; Zheng, Yu-Guo

2018-02-01

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is the key intermediate for synthesis of atorvastatin and rosuvastatin. Carbonyl reductase exhibits excellent activity toward tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) to synthesize (3R,5S)-CDHH. In this study, a whole cell biosynthesis reaction system to produce (3R,5S)-CDHH was constructed in organic solvents. A solution of 10% (v/v) Tween-80 was introduced to the reaction system as a co-solvent, which greatly enhanced biotransformation process, giving 98.9% yield, >99% ee and 1.8-fold higher space time yield in 5 h bioconversion of 1 M (S)-CHOH, compared with 98.7% yield and >99% ee in 9 h bioconversion of a purely aqueous reaction system. Moreover, a water-octanol biphasic reaction system was built and 20% of octanol was added as reservoir of substrate resulting in 98% yield, >99% ee and 4.08 mmol L -1  h -1  g -1 (wet cell weight) space time yield. This study paved a way for the whole cell biosynthesis of (3R,5S)-CDHH in mono and biphasic media. Copyright © 2017 Elsevier Ltd. All rights reserved.

Directed Evolution of Carbonyl Reductase from Rhodosporidium toruloides and Its Application in Stereoselective Synthesis of tert-Butyl (3R,5S)-6-Chloro-3,5-dihydroxyhexanoate.

PubMed

Liu, Zhi-Qiang; Wu, Lin; Zhang, Xiao-Jian; Xue, Ya-Ping; Zheng, Yu-Guo

2017-05-10

tert-Butyl (3R,5S)-6-chloro-3,5-dihydroxyhexanoate ((3R,5S)-CDHH) is a key intermediate of atorvastatin and rosuvastatin synthesis. Carbonyl reductase RtSCR9 from Rhodosporidium toruloides exhibited excellent activity toward tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH). For the activity of RtSCR9 to be improved, random mutagenesis and site-saturation mutagenesis were performed. Three positive mutants were obtained (mut-Gln95Asp, mut-Ile144Lys, and mut-Phe156Gln). These mutants exhibited 1.94-, 3.03-, and 1.61-fold and 1.93-, 3.15-, and 1.97-fold improvement in the specific activity and k cat /K m , respectively. Asymmetric reduction of (S)-CHOH by mut-Ile144Lys coupled with glucose dehydrogenase was conducted. The yield and enantiomeric excess of (3R,5S)-CDHH reached 98 and 99%, respectively, after 8 h bioconversion in a single batch reaction with 1 M (S)-CHOH, and the space-time yield reached 542.83 mmol L -1 h -1 g -1 wet cell weight. This study presents a new carbonyl reductase for efficient synthesis of (3R,5S)-CDHH.

Evaluation of ethyl tert-butyl ether biodegradation in a contaminated aquifer by compound-specific isotope analysis and in situ microcosms.

PubMed

Bombach, Petra; Nägele, Norbert; Rosell, Mònica; Richnow, Hans H; Fischer, Anko

2015-04-09

Ethyl tert-butyl ether (ETBE) is an upcoming groundwater pollutant in Europe whose environmental fate has been less investigated, thus far. In the present study, we investigated the in situ biodegradation of ETBE in a fuel-contaminated aquifer using compound-specific stable isotope analysis (CSIA), and in situ microcosms in combination with total lipid fatty acid (TLFA)-stable isotope probing (SIP). In a first field investigation, CSIA revealed insignificant carbon isotope fractionation, but low hydrogen isotope fractionation of up to +14‰ along the prevailing anoxic ETBE plume suggesting biodegradation of ETBE. Ten months later, oxygen injection was conducted to enhance the biodegradation of petroleum hydrocarbons (PH) at the field site. Within the framework of this remediation measure, in situ microcosms loaded with [(13)C6]-ETBE (BACTRAP(®)s) were exposed for 119 days in selected groundwater wells to assess the biodegradation of ETBE by TLFA-SIP under the following conditions: (i) ETBE as main contaminant; (ii) ETBE as main contaminant subjected to oxygen injection; (iii) ETBE plus other PH; (iv) ETBE plus other PH subjected to oxygen injection. Under all conditions investigated, significant (13)C-incorporation into microbial total lipid fatty acids extracted from the in situ microcosms was found, providing clear evidence of ETBE biodegradation. Copyright © 2014 Elsevier B.V. All rights reserved.

Transformation of Unsaturated Fatty Acids/Esters to Corresponding Keto Fatty Acids/Esters by Aerobic Oxidation with Pd(II)/Lewis Acid Catalyst.

PubMed

Senan, Ahmed M; Zhang, Sicheng; Zeng, Miao; Chen, Zhuqi; Yin, Guochuan

2017-08-16

Utilization of renewable biomass to partly replace the fossil resources in industrial applications has attracted attention due to the limited fossil feedstock with the increased environmental concerns. This work introduced a modified Wacker-type oxidation for transformation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, in which Cu 2+ cation was replaced with common nonredox metal ions, that is, a novel Pd(II)/Lewis acid (LA) catalyst. It was found that adding nonredox metal ions can effectively promote Pd(II)-catalyzed oxidation of unsaturated fatty acids/esters to the corresponding keto fatty acids/esters, even much better than Cu 2+ , and the promotional effect is highly dependent on the Lewis acidity of added nonredox metal ions. The improved catalytic efficiency is attributed to the formation of heterobimetallic Pd(II)/LA species, and the oxidation mechanism of this Pd(II)/LA catalyst is also briefly discussed.

Catalytic performance of strong acid catalyst: Methyl modified SBA-15 loaded perfluorinated sulfonic acid obtained by the waste perfluorinated sulfonic acid ion exchange membrane

NASA Astrophysics Data System (ADS)

Jiang, Tingshun; Huang, Qiuyan; Li, Yingying; Fang, Minglan; Zhao, Qian

2018-02-01

Mesoporous molecular sieve (SBA-15) was modified using the trimethylchlorosilane as functional agent and the silylation SBA-15 mesoporous material was prepared in this work. The alcohol solution of perfluorinated sulfonic acid dissolved from the waste perfluorinated sulfonic acid ion exchange membrane (PFSIEM) was loaded onto the resulting mesoporous material by the impregnation method and their physicochemical properties were characterized by FT-IR, N2-physisorption, XRD, TG-DSC and TEM. The catalytic activities of these synthesized solid acid catalysts were evaluated by alkylation of phenol with tert-butyl alcohol. The influence of reaction temperature, weight hour space velocity (WHSV) and reaction time on the phenol conversion and product selectivity were assessed by means of a series of experiments. The results showed that with the increase of the active component of the catalyst, these catalysts still remained good mesoporous structure, but the mesoporous ordering decreased to some extent. These catalysts exhibited good catalytic performance for the alkylation of phenol with tert-butanol. The maximum phenol conversion of 89.3% with 70.9% selectivity to 4-t-butyl phenol (4-TBP) was achieved at 120 °C and the WHSV is 4 h-1. The methyl group was loaded on the surface of the catalyst by trimethylchlorosilane. This is beneficial to retard the deactivation of the catalyst. In this work, the alkylation of phenol with tert-butyl alcohol were carried out using the methyl modified SBA-15 mesoporous materials loaded perfluorinated sulfonic acid as catalysts. The results show that the resulting catalyst exhibited high catalytic activity.

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.

Isolation and Characterization of 4-tert-Butylphenol-Utilizing Sphingobium fuliginis Strains from Phragmites australis Rhizosphere Sediment▿ †

PubMed Central

Toyama, Tadashi; Momotani, Naonori; Ogata, Yuka; Miyamori, Yuji; Inoue, Daisuke; Sei, Kazunari; Mori, Kazuhiro; Kikuchi, Shintaro; Ike, Michihiko

2010-01-01

We isolated three Sphingobium fuliginis strains from Phragmites australis rhizosphere sediment that were capable of utilizing 4-tert-butylphenol as a sole carbon and energy source. These strains are the first 4-tert-butylphenol-utilizing bacteria. The strain designated TIK-1 completely degraded 1.0 mM 4-tert-butylphenol in basal salts medium within 12 h, with concomitant cell growth. We identified 4-tert-butylcatechol and 3,3-dimethyl-2-butanone as internal metabolites by gas chromatography-mass spectrometry. When 3-fluorocatechol was used as an inactivator of meta-cleavage enzymes, strain TIK-1 could not degrade 4-tert-butylcatechol and 3,3-dimethyl-2-butanone was not detected. We concluded that metabolism of 4-tert-butylphenol by strain TIK-1 is initiated by hydroxylation to 4-tert-butylcatechol, followed by a meta-cleavage pathway. Growth experiments with 20 other alkylphenols showed that 4-isopropylphenol, 4-sec-butylphenol, and 4-tert-pentylphenol, which have alkyl side chains of three to five carbon atoms with α-quaternary or α-tertiary carbons, supported cell growth but that 4-n-alkylphenols, 4-tert-octylphenol, technical nonylphenol, 2-alkylphenols, and 3-alkylphenols did not. The rate of growth on 4-tert-butylphenol was much higher than that of growth on the other alkylphenols. Degradation experiments with various alkylphenols showed that strain TIK-1 cells grown on 4-tert-butylphenol could degrade 4-alkylphenols with variously sized and branched side chains (ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, tert-pentyl, n-hexyl, n-heptyl, n-octyl, tert-octyl, n-nonyl, and branched nonyl) via a meta-cleavage pathway but not 2- or 3-alkylphenols. Along with the degradation of these alkylphenols, we detected methyl alkyl ketones that retained the structure of the original alkyl side chains. Strain TIK-1 may be useful in the bioremediation of environments polluted by 4-tert-butylphenol and various other 4-alkylphenols. PMID:20802076

Efficacy of Myricetin as an Antioxidant in Methyl Esters of Soybean Oil

USDA-ARS?s Scientific Manuscript database

The antioxidant activity of myricetin, a natural flavonol found in fruits and vegetables, was determined in soybean oil methyl esters (SME) and compared with alpha-tocopherol and tert-butylhydroquinone (TBHQ) over a 90 day period employing EN 14112, acid value, and kinematic viscosity methods. Myri...

Synthesis, spectroscopy, magnetic and redox behaviors of copper(II) complexes with tert-butylated salen type ligands bearing bis(4-aminophenyl)ethane and bis(4-aminophenyl)amide backbones.

PubMed

Kasumov, Veli T; Yerli, Yusuf; Kutluay, Aysegul; Aslanoglu, Mehmet

2013-03-01

New salen type ligands, N,N'-bis(X-3-tert-butylsalicylidene)-4,4'-ethylenedianiline [(X=H (1), 5-tert-butyl (2)] and N,N'-bis(X-3-tert-butylsalicylidene)-4,4'-amidedianiline [X=H (3), 5-tert (4)] and their copper(II) complexes 5-8, have been synthesized. Their spectroscopic (IR, (1)H NMR, UV/vis, ESR) properties, as well as magnetic and redox-reactivity behavior are reported. IR spectra of 7 and 8 indicate the coordination of amide oxygen atoms of 3 and 4 ligands to Cu(II). The solid state ESR spectra of 5-8 exhibits less informative exchange narrowed isotropic or anisotropic signals with weak unresolved low field patterns. The magnetic moments of 5 (2.92 μ(B) per Cu(II)) and 6 (2.79 μ(B) per Cu(II)) are unusual for copper(II) complexes and considerably higher than those for complexes 7 and 8. Cryogenic measurements (300-10 K) show weak antiferromagnetic exchange interactions between the copper(II) centers in complexes 6 and 8. The results of electrochemical and chemical redox-reactivity studies are discussed. Copyright © 2012 Elsevier B.V. All rights reserved.

40 CFR 721.2950 - Carboxylic acid glycidyl esters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Carboxylic acid glycidyl esters. 721... Substances § 721.2950 Carboxylic acid glycidyl esters. (a) Chemical substances and significant new uses subject to reporting. (1) The chemical substance identified generically as carboxylic acid glycidyl ester...

2-(4-Bromo­benz­yl)-5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra­methoxy­calix[4]arene

PubMed Central

Fischer, Conrad; Lin, Guisheng; Seichter, Wilhelm; Weber, Edwin

2009-01-01

In the title compound, C55H69BrO4, the calixarene mol­ecule displays a ‘partial cone’ conformation bearing the lateral substituent in a sterically favorable equatorial arrangement between two syn-orientated arene units. The crystal packing is stabilized by weak C—H⋯π contacts, involving one tert-butyl group, and π–stacking inter­actions of the lateral bromo­benzene units [centroid–centroid distance = 3.706 (1) Å]. PMID:21582956

40 CFR 721.1732 - Nitrobenzoic acid octyl ester.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Nitrobenzoic acid octyl ester. 721... Substances § 721.1732 Nitrobenzoic acid octyl ester. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as nitrobenzoic acid octyl ester (PMN P-93-343...

Microbial toxicity of methyl tert-butyl ether (MTBE) determined with fluorescent and luminescent bioassays.

PubMed

Roslev, Peter; Lentz, Trine; Hesselsoe, Martin

2015-02-01

The inhibitory effects of the fuel additive methyl tert-butyl ether (MTBE) and potential degradation products tert-butanol (TBA) and formaldehyde was examined using mixed microbial biomass, and six strains of bioluminescent bacteria and yeast. The purpose was to assess microbial toxicity with quantitative bioluminescent and fluorescent endpoints, and to identify sensitive proxies suitable for monitoring MTBE contamination. Bioluminescent Aliivibrio fischeri DSM 7151 (formerly Vibrio fischeri) appeared highly sensitive to MTBE exposure, and was a superior test organisms compared to lux-tagged Escherichia coli DH5α, Pseudomonas fluorescens DF57-40E7 and Saccharomyces cerevisiae BLYR. EC10 and EC50 for acute MTBE toxicity in A. fischeri were 1.1 and 10.9 mg L(-1), respectively. Long term (24h) MTBE exposure resulted in EC10 values of 0.01 mg L(-1). TBA was significantly less toxic with EC10 and EC50 for acute and chronic toxicity >1000 mg L(-1). Inhibition of bioluminescence was generally a more sensitive endpoint for MTBE toxicity than measuring intracellular ATP levels and heterotrophic CO2 assimilation. A weak estrogenic response was detected for MTBE at concentrations ⩾ 3.7 g L(-1) using an estrogen inducible bioluminescent yeast strain (S. cerevisiae BLYES). Microbial hydrolytic enzyme activity in groundwater was affected by MTBE with EC10 values of 0.5-787 mg L(-1), and EC50 values of 59-3073 for alkaline phosphatase, arylsulfatase, beta-1,4-glucanase, N-acetyl-beta-d-glucosaminidase, and leucine-aminopeptidase. Microbial alkaline phosphatase and beta-1,4-glucanase activity were most sensitive to MTBE exposure with EC50 ⩽ 64.8 mg L(-1). The study suggests that bioassays with luminescent A. fischeri, and fluorescent assays targeting hydrolytic enzyme activity are good candidates for monitoring microbial MTBE toxicity in contaminated water. Copyright © 2014 Elsevier Ltd. All rights reserved.

Determining Phthalic Acid Esters Using Terahertz Time Domain Spectroscopy

NASA Astrophysics Data System (ADS)

Liu, L.; Shen, L.; Yang, F.; Han, F.; Hu, P.; Song, M.

2016-09-01

In this report terahertz time domain spectroscopy (THz-TDS) is applied for determining phthalic acid esters (PAEs) in standard materials. We reported the THz transmission spectrum in the frequency range of 0.2 to 2.0 THz for three PAEs: di-n-butyl phthalate (DBP), di-isononyl phthalate (DINP), and di-2-ethylhexyl phthalate ester (DEHP). The study provided the refractive indices and absorption features of these materials. The absorption spectra of three PAEs were simulated by using Gaussian software with Density Functional Theory (DFT) methods. For pure standard PAEs, the values of the refractive indices changed between 1.50 and 1.60. At 1.0 THz, the refractive indices were 1.524, 1.535, and 1.563 for DINP, DEHP, and DBP, respectively. In this experiment different concentrations of DBP were investigated using THz-TDS. Changes were measured in the low THz frequency range for refractive indices and characteristic absorption. The results indicated that THz-TDS is promising as a new method in determining PAEs in many materials. The results of this study could be used to support the practical application of THz-TDS in quality detection and food monitoring. In particular, this new technique could be used in detecting hazardous materials and other substances present in wine or foods.

21 CFR 172.854 - Polyglycerol esters of fatty acids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Polyglycerol esters of fatty acids. 172.854 Section... HUMAN CONSUMPTION Multipurpose Additives § 172.854 Polyglycerol esters of fatty acids. Polyglycerol esters of fatty acids, up to and including the decaglycerol esters, may be safely used in food in...

21 CFR 172.854 - Polyglycerol esters of fatty acids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Polyglycerol esters of fatty acids. 172.854... HUMAN CONSUMPTION Multipurpose Additives § 172.854 Polyglycerol esters of fatty acids. Polyglycerol esters of fatty acids, up to and including the decaglycerol esters, may be safely used in food in...

Microwave-assisted synthesis and crystal structure of oxo(diperoxo)(4,4'-di-tert-butyl-2,2'-bipyridine)-molybdenum(VI).

PubMed

Amarante, Tatiana R; Almeida Paz, Filipe A; Gago, Sandra; Gonçalves, Isabel S; Pillinger, Martyn; Rodrigues, Alírio E; Abrantes, Marta

2009-09-16

The oxodiperoxo complex MoO(O2)(2)(tbbpy) (tbbpy = 4,4'-di-tert-butyl-2,2'- bipyridine) was isolated from the reaction of MoO2Cl(2)(tbbpy) in water under microwaveassisted heating at 120 masculineC for 4 h. The structure of the oxodiperoxo complex was determined by single crystal X-ray diffraction. The Mo(VI) centre is seven-coordinated with a geometry which strongly resembles a highly distorted bipyramid. Individual MoO(O2)(2)(tbbpy) complexes are interdigitated along the [010] direction to form a column. The crystal structure is formed by the close packing of the columnar-stacked complexes. Interactions between neighbouring columns are essentially of van der Waals type mediated by the need to effectively fill the available space.

21 CFR 172.848 - Lactylic esters of fatty acids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactylic esters of fatty acids. 172.848 Section 172... CONSUMPTION Multipurpose Additives § 172.848 Lactylic esters of fatty acids. Lactylic esters of fatty acids... prepared from lactic acid and fatty acids meeting the requirements of § 172.860(b) and/or oleic acid...

Phenyl-alpha-tert-butyl nitrone reverses mitochondrial decay in acute Chagas' disease.

PubMed

Wen, Jian-Jun; Bhatia, Vandanajay; Popov, Vsevolod L; Garg, Nisha Jain

2006-12-01

In this study, we investigated the mechanism(s) of mitochondrial functional decline in acute Chagas' disease. Our data show a substantial decline in respiratory complex activities (39 to 58%) and ATP (38%) content in Trypanosoma cruzi-infected murine hearts compared with normal controls. These metabolic alterations were associated with an approximately fivefold increase in mitochondrial reactive oxygen species production rate, substantial oxidative insult of mitochondrial membranes and respiratory complex subunits, and >60% inhibition of mtDNA-encoded transcripts for respiratory complex subunits in infected myocardium. The antioxidant phenyl-alpha-tert-butyl nitrone (PBN) arrested the oxidative damage-mediated loss in mitochondrial membrane integrity, preserved redox potential-coupled mitochondrial gene expression, and improved respiratory complex activities (47 to 95% increase) and cardiac ATP level (>or=40% increase) in infected myocardium. Importantly, PBN resulted twofold decline in mitochondrial reactive oxygen species production rate in infected myocardium. Taken together, our data demonstrate the pathological significance of oxidative stress in metabolic decay and energy homeostasis in acute chagasic myocarditis and further suggest that oxidative injuries affecting mitochondrial integrity-dependent expression and activity of the respiratory complexes initiate a feedback cycle of electron transport chain inefficiency, increased reactive oxygen species production, and energy homeostasis in acute chagasic hearts. PBN and other mitochondria-targeted antioxidants may be useful in altering mitochondrial decay and oxidative pathology in Chagas' disease.

[Anaerobic biodegradation of phthalic acid esters (Paes) in municipal sludge].

PubMed

Liang, Zhi-Feng; Zhou, Wen; Lin, Qing-Qi; Yang, Xiu-Hong; Wang, Shi-Zhong; Cai, Xin-De; Qiu, Rong-Liang

2014-04-01

Phthalic acid esters (PAEs), a class of organic pollutants with potent endocrine-disrupting properties, are widely present in municipal sludge. Study of PAEs biodegradation under different anaerobic biological treatment processes of sludge is, therefore, essential for a safe use of sludge in agricultural practice. In this study, we selected two major sludge PAEs, i.e. di-n-butyl phthalate (DBP) and di-(2-enthylhexyl) phthalate (DEHP), to investigate their biodegradation behaviors in an anaerobic sludge digestion system and a fermentative hydrogen production system. The possible factors influencing PAEs biodegradation in relation to changes of sludge properties were also discussed. The results showed that the biodegradation of DBP reached 99.6% within 6 days, while that of DEHP was 46.1% during a 14-day incubation period in the anaerobic digestion system. By comparison, only 19.5% of DBP was degraded within 14 days in the fermentative hydrogen production system, while no degradation was detected for DEHP. The strong inhibition of the degradation of both PAEs in the fermentative hydrogen production system was ascribed to the decreases in microbial biomass and ratios of gram-positive bacteria/gram-negative bacteria and fungi/ bacteria, and the increase of concentrations of volatile fatty acids (e. g. acetic acid, propionic acid and butyric acid) during the fermentative hydrogen-producing process.

Application of AlkBGT and AlkL from Pseudomonas putida GPo1 for Selective Alkyl Ester ω-Oxyfunctionalization in Escherichia coli

PubMed Central

Eggink, Gerrit; Weusthuis, Ruud A.

2016-01-01

ABSTRACT The enzyme system AlkBGT from Pseudomonas putida GPo1 can efficiently ω-functionalize fatty acid methyl esters. Outer membrane protein AlkL boosts this ω-functionalization. In this report, it is shown that whole cells of Escherichia coli expressing the AlkBGT system can also ω-oxidize ethyl nonanoate (NAEE). Coexpression of AlkBGT and AlkL resulted in 1.7-fold-higher ω-oxidation activity on NAEE. With this strain, initial activity on NAEE was 70 U/g (dry weight) of cells (gcdw), 67% of the initial activity on methyl nonanoate. In time-lapse conversions with 5 mM NAEE the main product was 9-hydroxy NAEE (3.6 mM), but also 9-oxo NAEE (0.1 mM) and 9-carboxy NAEE (0.6 mM) were formed. AlkBGT also ω-oxidized ethyl, propyl, and butyl esters of fatty acids ranging from C6 to C10. Increasing the length of the alkyl chain improved the ω-oxidation activity of AlkBGT on esters of C6 and C7 fatty acids. From these esters, application of butyl hexanoate resulted in the highest ω-oxidation activity, 82 U/gcdw. Coexpression of AlkL only had a positive effect on ω-functionalization of substrates with a total length of C11 or longer. These findings indicate that AlkBGT(L) can be applied as a biocatalyst for ω-functionalization of ethyl, propyl, and butyl esters of medium-chain fatty acids. IMPORTANCE Fatty acid esters are promising renewable starting materials for the production of ω-hydroxy fatty acid esters (ω-HFAEs). ω-HFAEs can be used to produce sustainable polymers. Chemical conversion of the fatty acid esters to ω-HFAEs is challenging, as it generates by-products and needs harsh reaction conditions. Biocatalytic production is a promising alternative. In this study, biocatalytic conversion of fatty acid esters toward ω-HFAEs was investigated using whole cells. This was achieved with recombinant Escherichia coli cells that produce the AlkBGT enzymes. These enzymes can produce ω-HFAEs from a wide variety of fatty acid esters. Medium-chain-length acids (C

Reaction of alkylphenols with acetals. II. Reaction of 4methyl-2-tert-butylphenol with dimethoxymethane

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

Starikova, O.F.; Gurvich, Y.A.; Kumok, S.T.

1985-12-20

The authors explain how di(hydroxydialkylaryl) derivatives of methane play an important role in the inhibition of oxidation processes in polymers, oils, fuels, and other organic materials. They investigate the reaction of 4-methyl-2-tert-butylphenol with dimethoxymethane, and established that the reaction mass contained 2-methoxymethyl-4-6-tert-butylphenol. The formation and the transformations of 2-methoxymethyl-4-methyl-6-tert-butylphenol do not have a significant effect on the synthesis of di(2-hydroxy-5-methyl-3-tert-butylphenyl) methane from 4-methyl-2-tert-butyl-phenol and dimethoxymethane.

21 CFR 172.854 - Polyglycerol esters of fatty acids.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Polyglycerol esters of fatty acids. 172.854... § 172.854 Polyglycerol esters of fatty acids. Polyglycerol esters of fatty acids, up to and including..., safflower oil, sesame oil, soybean oil, and tallow and the fatty acids derived from these substances...

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Glyceryl-lacto esters of fatty acids. 172.852... HUMAN CONSUMPTION Multipurpose Additives § 172.852 Glyceryl-lacto esters of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in...

A comparative study of biodiesel production using methanol, ethanol, and tert-butyl methyl ether (MTBE) under supercritical conditions.

PubMed

Farobie, Obie; Matsumura, Yukihiko

2015-09-01

In this study, biodiesel production under supercritical conditions among methanol, ethanol, and tert-butyl methyl ether (MTBE) was compared in order to elucidate the differences in their reaction behavior. A continuous reactor was employed, and experiments were conducted at various reaction temperatures (270-400 °C) and reaction times (3-30 min) and at a fixed pressure of 20 MPa and an oil-to-reactant molar ratio of 1:40. The results showed that under the same reaction conditions, the supercritical methanol method provided the highest yield of biodiesel. At 350 °C and 20 MPa, canola oil was completely converted to biodiesel after 10, 30, and 30 min in the case of - supercritical methanol, ethanol, and MTBE, respectively. The reaction kinetics of biodiesel production was also compared for supercritical methanol, ethanol, and MTBE. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effect of drug lipophilicity on in vitro release rate from oil vehicles using nicotinic acid esters as model prodrug derivatives.

PubMed

Weng Larsen, S; Engelbrecht Thomsen, A E; Rinvar, E; Friis, G J; Larsen, C

2001-03-23

The rate constants for transfer of a homologous series of nicotinic acid esters from oil vehicles to aqueous buffer phases were determined using a rotating dialysis cell. The chemical stability of butyl nicotinate has been investigated at 60 degrees C over pH range 0.5--10. Maximum stability occurs at pH 4--5 and an inflection point was seen around the pK(a). For the nicotinic acid esters, a linear correlation was established between the first-order rate constant related to attainment of equilibrium, k(obs) and the apparent partition coefficient, P(app): log k(obs)=-0.83log P(app)+0.26 (k(obs) in h(-1), n=9). For hexyl nicotinate with a true partition coefficient of 4 it was possible to determine k(obs) by decreasing pH in the aqueous release medium to 2.05. Thus, under the latter experimental conditions estimation of the relative release rates for the esters were performed. The ratio between the specific rate constant k(ow), related to the transport from oil vehicle to aqueous phase, for ethyl and hexyl nicotinate was 139. The hydrophobic substituent constant for a methylene group, pi(CH(2)), was determined for nicotinic acid esters in different oil/buffer partitioning systems to 0.54--0.58. Addition of hydroxypropyl-beta-cyclodextrin to the aqueous release medium did not enhance the transport rate of the esters from the oil phase.

40 CFR 721.10685 - Phosphoric acid, mixed esters (generic).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphoric acid, mixed esters (generic... Specific Chemical Substances § 721.10685 Phosphoric acid, mixed esters (generic). (a) Chemical substance... phosphoric acid, mixed esters (PMN P-13-170) is subject to reporting under this section for the significant...

Synthesis and dynamic NMR study of ketenimines derived from tert-butyl isocyanide, alkyl 2-arylamino-2-oxo-acetates, and dialkyl acetylenedicarboxylates.

PubMed

Yavari, Issa; Nasiri, Farough; Djahaniani, Horieh

2004-01-01

The adduct produced in the reaction between tert-butyl isocyanide and dialkyl acetylenedicarboxylates was trapped by alkyl 2-arylamino-2-oxo-acetates. When the aryl group is 2-methyl-6-nitrophenyl or 2,6-di-isopropylphenyl, the product exists as two stable rotamers at room temperature as a result of restricted rotation around the Ar-N single bond. When the aryl group is 1-naphthyl or 8-quinolinyl, dynamic NMR effects are observed in the 1H NMR spectra. The calculated free-energy of activation for interconversion of the rotational isomers in 1-naphthyl and 8-quinolinyl derivatives amounts to about 99+/-2 and 68.5+/-2 kJ mol(-1), respectively.

Methods of refining and producing isomerized fatty acid esters and fatty acids from natural oil feedstocks

DOEpatents

Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.; Beltran, Leslie V.; Kunz, Linda A.; Pals, Tessa M.; Quinn, Jordan R; Behrends, Jr., Raymond T.; Bernhardt, Randal J.

2016-07-05

Methods are provided for refining natural oil feedstocks and producing isomerized esters and acids. The methods comprise providing a C4-C18 unsaturated fatty ester or acid, and isomerizing the fatty acid ester or acid in the presence of heat or an isomerization catalyst to form an isomerized fatty ester or acid. In some embodiments, the methods comprise forming a dibasic ester or dibasic acid prior to the isomerizing step. In certain embodiments, the methods further comprise hydrolyzing the dibasic ester to form a dibasic acid. In certain embodiments, the olefin is formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having unsaturated esters.

21 CFR 172.848 - Lactylic esters of fatty acids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Lactylic esters of fatty acids. 172.848 Section... HUMAN CONSUMPTION Multipurpose Additives § 172.848 Lactylic esters of fatty acids. Lactylic esters of fatty acids may be safely used in food in accordance with the following prescribed conditions: (a) They...

Mono-, di-, and tri- tert-butyl ethers of glycerol . A molecular spectroscopic study

NASA Astrophysics Data System (ADS)

Jamróz, Małgorzata E.; Jarosz, Małgorzata; Witowska-Jarosz, Janina; Bednarek, Elżbieta; Tęcza, Witold; Jamróz, Michał H.; Dobrowolski, Jan Cz.; Kijeński, Jacek

2007-07-01

MS, NMR, IR and Raman molecular spectroscopy techniques were applied to characterize 3- tert-butoxy-propane-1,2-diol, 1,3-di- tert-butoxy-propan-2-ol, and 1,2,3-tri- tert-butoxy-propane. These ethers are the main products of glycerol etherification reaction and are excellent oxygen additives for diesel fuel. Computational DFT/ B3LYP/6-31G ** studies were performed to support and rationalize both vibrational spectroscopy analysis and the isomer ratio.

Interactions of poly(tert-butyl acrylate)-poly(styrene) diblock copolymers with lipids at the air-water interface.

PubMed

Mudgil, Poonam; Dennis, Gary R; Millar, Thomas J

2006-08-29

Diblock copolymers with hydrophilic poly(tert-butyl acrylate) (PtBA) and hydrophobic poly(styrene) (PS) blocks were synthesized with a view to use them as a surfactant in tear film for increasing the ocular comfort in dry eye syndrome. Interactions of six PtBA-PS copolymers with four important lipids found in the tear film, namely cholesterol, cholesteryl palmitate, dipalmitoyl phosphatidylcholine, and phosphatidylinositol, were studied at the air-water interface using a Langmuir trough. Thermodynamics of mixing of the copolymers and the lipids in the mixed monolayers was determined by calculating excess free energy of mixing. The diblock copolymers showed repulsive interactions with cholesteol and cholesteryl palmitate, near neutral interactions with dipalmitoyl phosphatidylcholine, and attractive interactions with phosphatidylinositol. The lipids interacted with the PS component of the copolymer. The results indicate that a copolymer with a small hydrophilic group and a big hydrophobic group can be a likely candidate for forming stable interactions with the lipids present in the tear film and hence increase the ocular comfort.

Emulsion Polymerization of Butyl Acrylate: Spin Trapping and EPR Study

NASA Technical Reports Server (NTRS)

Kim, S.; Westmoreland, D.

1994-01-01

The propagating radical in the emulsion polymerization reaction of butyl acrylate was detected by Electron Paramagnetic Resonance spectroscopy using two spin trapping agents, 2-methyl-2nitrosopropane and alpha -N-tert-butylnitrone.

Highly efficient enzymatic synthesis of tert-butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate with a mutant alcohol dehydrogenase of Lactobacillus kefir.

PubMed

He, Xiu-Juan; Chen, Shao-Yun; Wu, Jian-Ping; Yang, Li-Rong; Xu, Gang

2015-11-01

tert-Butyl (S)-6-chloro-5-hydroxy-3-oxohexanoate ((S)-CHOH) is a valuable chiral synthon, which is used for the synthesis of the cholesterol-lowering drugs atorvastatin and rosuvastatin. To date, only the alcohol dehydrogenases from Lactobacillus brevis (LbADH) and Lactobacillus kefir (LkADH) have demonstrated catalytic activity toward the asymmetric reduction of tert-butyl 6-chloro-3,5-dioxohexanoate (CDOH) to (S)-CHOH. Herein, a tetrad mutant of LkADH (LkTADH), A94T/F147L/L199H/A202L, was screened to be more efficient in this bioreduction process, exhibiting a 3.7- and 42-fold improvement in specific activity toward CDOH (1.27 U/mg) over LbADH (0.34 U/mg) and wild-type LkADH (0.03 U/mg), respectively. The molecular basis for the improved catalytic activity of LkTADH toward CDOH was investigated using homology modeling and docking analysis. Two major issues had a significant impact on the biocatalytic efficiency of this process, including (i) the poor aqueous stability of the substrate and (ii) partial substrate inhibition. A fed-batch strategy was successfully developed to address these issues and maintain a suitably low substrate concentration throughout the entire process. Several other parameters were also optimized, including the pH, temperature, NADP(+) concentration and cell loading. A final CDOH concentration of 427 mM (100 g/L) gave (S)-CHOH in 94 % yield and 99.5 % e.e. after a reaction time of 38 h with whole cells expressing LkTADH. The space-time yield and turnover number of NADP(+) in this process were 10.6 mmol/L/h and 16,060 mol/mol, respectively, which were the highest values ever reported. This new approach therefore represents a promising alternative for the efficient synthesis of (S)-CHOH.

Protective effects of hesperidin against oxidative stress of tert-butyl hydroperoxide in human hepatocytes.

PubMed

Chen, Mingcang; Gu, Honggang; Ye, Yiyi; Lin, Bing; Sun, Lijuan; Deng, Weiping; Zhang, Jingzhe; Liu, Jianwen

2010-10-01

Increasing evidence regarding free radical generating agents and the inflammatory process suggest that accumulation of reactive oxygen species (ROS) could involve hepatotoxicity. Hesperidin, a naturally occurring flavonoid presents in fruits and vegetables, has been reported to exert a wide range of pharmacological effects that include antioxidant, anti-inflammatory, antihypercholesterolemic, and anticarcinogenic actions. However, the cytoprotection and mechanism of hesperidin to neutralize oxidative stress in human hepatic L02 cells remain unclear. In this work, we assessed the capability of hesperidin to prevent tert-butyl hydroperoxide (t-BuOOH)-induced cell damage by augmenting cellular antioxidant defense. Hesperidin significantly protected hepatocytes against t-BuOOH-induced cell cytotoxicity, such as mitochondrial membrane potential (MMP) deplete and lactate dehydrogenase (LDH) release. Hesperidin also remarkably prevented indicators of oxidative stress, such as the ROS and lipid peroxidation level in a dose-dependent manner. Western blot showed that hesperidin facilitated ERK/MAPK phosphorylation which appeared to be responsible for nuclear translocation of Nrf2, thereby inducing cytoprotective heme oxygenase-1 (HO-1) expression. Based on the results described above, it suggested that hesperidin has potential as a therapeutic agent in the treatment of oxidative stress-related hepatocytes injury and liver dysfunctions. Copyright © 2010 Elsevier Ltd. All rights reserved.

Anti-Aspergillus activity of green coffee 5-O-caffeoyl quinic acid and its alkyl esters.

PubMed

Suárez-Quiroz, M L; Alonso Campos, A; Valerio Alfaro, G; González-Ríos, O; Villeneuve, P; Figueroa-Espinoza, M C

2013-01-01

The antifungal activities of 5-O-caffeoyl quinic acid (5-CQA) and of methyl, butyl, octyl, and dodecyl esters or 5-CQA, were tested on five toxigenic moulds from the Aspergillus genus (Aspergillus flavus, Aspergillus nomius, Aspergillus ochraceus, Aspergillus parasiticus, Aspergillus westerdijkiae). These mycotoxin producers' moulds may contaminate many types of food crops throughout the food chain posing serious health hazard to animals and humans. The use of chemical methods to decrease mycotoxin producer moulds contamination on food crops in the field, during storage, and/or during processing, has been proved to be efficient. In this work, the antifungal effect of 5-CQA and a homologous series of 5-CQA esters (methyl, butyl, octyl, dodecyl), was investigated using the microdilution method and the minimum inhibitory concentrations (MIC50 and MIC80). All molecules presented antifungal activity, and two esters showed a MIC for all fungi: octyl (MIC50 ≤ 0.5-0.75 mg/mL, MIC80 = 1.0-1.5 mg/mL) and dodecyl (MIC50 = 0.75-1.25 mg/mL) chlorogenates. Dodecyl chlorogenate showed a MIC80 (1.5 mg/mL) only for A. parasiticus. The maximum percent of growth inhibition on aspergillii was observed with octyl (78.4-92.7%) and dodecyl (54.5-83.7%) chlorogenates, being octyl chlorogenate the most potent antifungal agent. It was thus concluded that lipophilization improved the antifungal properties of 5-CQA, which increased with the ester alkyl chain length, exhibiting a cut-off effect at 8 carbons. As far as we know, it is the first report demonstrating that lipophilization may improve the antifungal activity of 5-CQA on five toxigenic moulds from the Aspergillus genus. Lipophilization would be a novel way to synthesize a new kind of antifungal agents with a good therapeutic value or a potential use as preservative in food or cosmetics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Enantioselective synthesis of chiral oxazolines from unactivated ketones and isocyanoacetate esters by synergistic silver/organocatalysis.

PubMed

Martínez-Pardo, Pablo; Blay, Gonzalo; Muñoz, M Carmen; Pedro, José R; Sanz-Marco, Amparo; Vila, Carlos

2018-03-15

A multicatalytic approach that combines a bifunctional Brønsted base-squaramide organocatalyst and Ag + as Lewis acid has been applied in the reaction of unactivated ketones with tert-butyl isocyanoacetate to give chiral oxazolines bearing a quaternary stereocenter. The formal [3+2] cycloaddition provided high yields of the corresponding cis-oxazolines with good diastereoselectivity and excellent enantioselectivity, being applied to aryl-alkyl and alkyl-alkyl ketones.

40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

Code of Federal Regulations, 2010 CFR

2010-07-01

..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction...

40 CFR 721.10125 - Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and alkenoic acid...

Code of Federal Regulations, 2011 CFR

2011-07-01

..., reaction products with polyaminocarbomonocycle and alkenoic acid alkyl ester (generic). 721.10125 Section... Substances § 721.10125 Alkenedioic acid, dialkyl ester, reaction products with polyaminocarbomonocycle and.... (1) The chemical substances identified generically as alkenedioic acid, dialkyl ester, reaction...

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

Code of Federal Regulations, 2014 CFR

2014-04-01

... § 172.852 Glyceryl-lacto esters of fatty acids. Glyceryl-lacto esters of fatty acids (the lactic acid... conditions: (a) They are manufactured from glycerin, lactic acid, and fatty acids conforming with § 172.860...

Ground-State Distortion in N-Acyl-tert-butyl-carbamates (Boc) and N-Acyl-tosylamides (Ts): Twisted Amides of Relevance to Amide N-C Cross-Coupling.

PubMed

Szostak, Roman; Shi, Shicheng; Meng, Guangrong; Lalancette, Roger; Szostak, Michal

2016-09-02

Amide N-C(O) bonds are generally unreactive in cross-coupling reactions employing low-valent transition metals due to nN → π*C═O resonance. Herein we demonstrate that N-acyl-tert-butyl-carbamates (Boc) and N-acyl-tosylamides (Ts), two classes of acyclic amides that have recently enabled the development of elusive amide bond N-C cross-coupling reactions with organometallic reagents, are intrinsically twisted around the N-C(O) axis. The data have important implications for the design of new amide cross-coupling reactions with the N-C(O) amide bond cleavage as a key step.

Arbuscular mycorrhizal fungi in a wetland constructed for benzene-, methyl tert-butyl ether- and ammonia-contaminated groundwater bioremediation

PubMed Central

Fester, Thomas

2013-01-01

Arbuscular mycorrhizal fungi (AMF), which are present in most natural environments, have demonstrated capacity to promote biodegradation of organic pollutants in the greenhouse. However, it is not certain whether AMF can spontaneously establish in phytoremediation systems constructed to decontaminate groundwater, because of the unusual conditions during the construction and operation of such systems. To assess this possibility, root samples from a wetland constructed for the phytoremediation of groundwater contaminated with benzene, methyl tert-butyl ether and ammonia were analysed. Substantial AMF colonization was observed in plant roots sampled close to the inlet of a basin filled with fine gravel and planted with Phragmites australis. In addition, analysis of a fragment of the nuclear large ribosomal subunit, amplified by nested PCR, revealed the presence of AMF molecular operational taxonomic units closely related to Funneliformis mosseae and Rhizophagus irregularis in the samples. These findings demonstrate the capacity of generalist AMF strains to establish spontaneously, rapidly and extensively in groundwater bioremediation technical installations. PMID:22846140

LASERS IN MEDICINE: Quantum efficiency of the laser-excited singlet-oxygen-sensitised delayed fluorescence of the zinc complex of tetra(4-tert-butyl)phthalocyanine

NASA Astrophysics Data System (ADS)

Bashtanov, M. E.; Drozdova, N. N.; Krasnovskii, A. A.

1999-12-01

An investigation was made of the ratios of the intensity Idf of the singlet-oxygen(1O2)-sensitised delayed fluorescence of the zinc complex of tetra(4-tert-butyl)phthalocyanine (ZnTBPc), with the maximum at λ = 685 nm, to the intensity I1270 of the photosensitised phosphorescence of 1O2 with the maximum at λ = 1270 nm in deuterated benzene when excited with λ = 337 nm nitrogen-laser pulses. Depending on the energy density of the laser radiation (0.25 — 0.7 mJ cm-2) and on the concentration of ZnTBPc (0.06 — 3.4 μM), the ratio of the zero-time intensities of the delayed fluorescence of ZnTBPc and of the singlet-oxygen phosphorescence Idf0/I12700 varied from 0.01 to 0.2 in air-saturated solutions of ZnTBPc. The intensity Idf0 decreased fivefold as a result of saturation with oxygen of air-saturated solutions. The quantum efficiency of the delayed fluorescence was represented by the coefficient α =(Idf0/I12700)kr/(γf[1O2]0[ZnTBPc]), where [1O2]0 is the zero-time concentration of 1O2 after a laser shot; kr is the rate constant of radiative deactivation of 1O2 in the investigated solvent; γf is the quantum yield of the ZnTBPc fluorescence. It was established that in the case of air-saturated solutions of ZnTBPc this coefficient was approximately 200 times less than for metal-free tetra(4-tert-butyl)phthalocyanine and its absolute value was ~2 × 1011 M-2 s-1.

Preparation of Langmuir-Blodgett thin films of calix[6]arenes and p-tert butyl group effect on their gas sensing properties

NASA Astrophysics Data System (ADS)

Ozmen, Mustafa; Ozbek, Zikriye; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, Rifat

2015-12-01

Organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of p-tert-butyl calix[6]arene and calix[6]arene, and their certain characterization are reported in this work. LB films of these calixarenes have been characterized by contact angle measurement, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. Forming of stable monolayers was observed at the water surface using surface pressure-area isotherm graph. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Due to the adsorption of vapors into the LB film structures; they yield a response to all vapors as of large, fast, and reproducible.

Protective effect of Hibiscus anthocyanins against tert-butyl hydroperoxide-induced hepatic toxicity in rats.

PubMed

Wang, C J; Wang, J M; Lin, W L; Chu, C Y; Chou, F P; Tseng, T H

2000-05-01

Hibiscus anthocyanins (HAs), a group of natural pigments occurring in the dried flowers of Hibiscus sabdariffa L., which is a local soft drink material and medical herb, were studied for antioxidant bioactivity. The preliminary study showed that HAs were able to quench the free radicals of 1,1-diphenyl-2-picrylhydrazyl. This antioxidant bioactivitiy was further evaluated using the model of tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity in rat primary hepatocytes and hepatotoxicity in rats. The results demonstrated that HAs, at the concentrations of 0.10 and 0.20 mg/ml, significantly decreased the leakage of lactate dehydrogenase and the formation of malondialdehyde induced by a 30-min treatment of t-BHP (1.5 mM). The in vivo investigation showed that the oral pretreatment of HAs (100 and 200 mg/kg) for 5 days before a single dose of t-BHP (0.2 mmol/kg, ip) significantly lowered the serum levels of hepatic enzyme markers (alanine and aspartate aminotransferase) and reduced oxidative liver damage. The histopathological evaluation of the liver revealed that Hibiscus pigments reduced the incidence of liver lesions including inflammatory, leucocyte infiltration, and necrosis induced by t-BHP in rats. Based on the results described above, we speculate that Hibiscus pigments may play a role in the prevention of oxidative damage in living systems.

Naturally Occurring Cinnamic Acid Sugar Ester Derivatives.

PubMed

Tian, Yuxin; Liu, Weirui; Lu, Yi; Wang, Yan; Chen, Xiaoyi; Bai, Shaojuan; Zhao, Yicheng; He, Ting; Lao, Fengxue; Shang, Yinghui; Guo, Yu; She, Gaimei

2016-10-24

Cinnamic acid sugar ester derivatives (CASEDs) are a class of natural product with one or several phenylacrylic moieties linked with the non-anomeric carbon of a glycosyl skeleton part through ester bonds. Their notable anti-depressant and brains protective activities have made them a topic of great interest over the past several decades. In particular the compound 3',6-disinapoylsucrose, the index component of Yuanzhi (a well-known Traditional Chinese Medicine or TCM), presents antidepressant effects at a molecular level, and has become a hotspot of research on new lead drug compounds. Several other similar cinnamic acid sugar ester derivatives are reported in traditional medicine as compounds to calm the nerves and display anti-depression and neuroprotective activity. Interestingly, more than one third of CASEDs are distributed in the family Polygalaceae . This overview discusses the isolation of cinnamic acid sugar ester derivatives from plants, together with a systematic discussion of their distribution, chemical structures and properties and pharmacological activities, with the hope of providing references for natural product researchers and draw attention to these interesting compounds.

21 CFR 172.854 - Polyglycerol esters of fatty acids.

Code of Federal Regulations, 2012 CFR

2012-04-01

... approved emulsifiers in dry, whipped topping base. The fatty acids used in the production of the... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Polyglycerol esters of fatty acids. 172.854... HUMAN CONSUMPTION Multipurpose Additives § 172.854 Polyglycerol esters of fatty acids. Polyglycerol...

21 CFR 172.854 - Polyglycerol esters of fatty acids.

Code of Federal Regulations, 2013 CFR

2013-04-01

... approved emulsifiers in dry, whipped topping base. The fatty acids used in the production of the... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Polyglycerol esters of fatty acids. 172.854... HUMAN CONSUMPTION Multipurpose Additives § 172.854 Polyglycerol esters of fatty acids. Polyglycerol...

Structural, energetic, and UV-Vis spectral analysis of UVA filter 4-tert-butyl-4'-methoxydibenzoylmethane.

PubMed

Pinto da Silva, Luís; Ferreira, Paulo J O; Duarte, Darío J R; Miranda, Margarida S; Esteves da Silva, Joaquim C G

2014-02-27

The growing awareness of the harmful effects of ultraviolet (UV) solar radiation has increased the production and consumption of sunscreen products, which contain organic and inorganic molecules named UV filters that absorb, reflect, or scatter UV radiation, thus minimizing negative human health effects. 4-tert-Butyl-4'-methoxydibenzoylmethane (BMDBM) is one of the few organic UVA filters and the most commonly used. BMDBM exists in sunscreens in the enol form which absorbs strongly in the UVA range. However, under sunlight irradiation tautomerization occurs to the keto form, resulting in the loss of UV protection. In this study we have performed quantum chemical calculations to study the excited-state molecular structure and excitation spectra of the enol and keto tautomers of BMDBM. This knowledge is of the utmost importance as the starting point for studies aiming at the understanding of its activity when applied on human skin and also its fate once released into the aquatic environment. The efficiency of excitation transitions was rationalized based on the concept of molecular orbital superposition. The loss of UV protection was attributed to the enol → keto phototautomerism and subsequent photodegradation. Although this process is not energetically favorable in the singlet bright state, photodegradation is possible because of intersystem crossing to the first two triplet states.

Role of 6-shogaol in tert -butyl hydroperoxide-induced apoptosis of HepG2 cells.

PubMed

Kim, Sang Chan; Lee, Jong Rok; Park, Sook Jahr

2014-01-01

The aim of this study was to investigate the protective effects of 6-shogaol on tert-butyl hydroperoxide (tBHP)-induced oxidative stress leading to apoptosis in human hepatoma cell line HepG2. The cells were exposed to tBHP (100 μmol/l) after pretreatment with 6-shogaol (2.5 and 5 μmol/l), and then cell viability was measured. 6-Shogaol fully prevented HepG2 cell death caused by tBHP. Treatment of tBHP resulted in apoptotic cell death as assessed by TUNEL assay and the expression of apoptosis regulator proteins, Bcl-2 family, caspases and cytochrome c. Cells treated with 6-shogaol showed rapid reduction of apoptosis by restoring these markers of apoptotic cells. In addition, 6-shogaol significantly recovered disruption of mitochondrial membrane potential as a start sign of hepatic apoptosis induced by oxidative stress. In line with this observation, antioxidative 6-shogaol inhibited generation of reactive oxygen species and depletion of reduced glutathione in tBHP-stimulated HepG2 cells. Taken together, these results for the first time showed antioxidative and antiapoptotic activities of 6-shogaol in tBHP-treated hepatoma HepG2 cells, suggesting that 6-shogaol could be beneficial in hepatic disorders caused by oxidative stress. © 2014 S. Karger AG, Basel.

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

Code of Federal Regulations, 2012 CFR

2012-04-01

... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid...

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

Code of Federal Regulations, 2013 CFR

2013-04-01

... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid...

21 CFR 172.852 - Glyceryl-lacto esters of fatty acids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... esters of fatty acids (the lactic acid esters of mono- and diglycerides) may be safely used in food in accordance with the following prescribed conditions: (a) They are manufactured from glycerin, lactic acid...

Origin of estradiol fatty acid esters in human ovarian follicular fluid.

PubMed

Pahuja, S L; Kim, A H; Lee, G; Hochberg, R B

1995-03-01

The estradiol fatty acid esters are the most potent of the naturally occurring steroidal estrogens. These esters are present predominantly in fat, where they are sequestered until they are hydrolyzed by esterases. Thus they act as a preformed reservoir of estradiol. We have previously shown that ovarian follicular fluid from patients undergoing gonadotropin stimulation contains very high amounts of estradiol fatty acid esters (approximately 10(-7) M). The source of these esters is unknown. They can be formed by esterification of estradiol in the follicular fluid by lecithin:cholesterol acyltransferase (LCAT), or in the ovary by an acyl coenzyme A:acyltransferase. In order to determine which of these enzymatic processes is the source of the estradiol esters in the follicular fluid, we incubated [3H]estradiol with follicular fluid and cells isolated from human ovarian follicular fluid and characterized the fatty acid composition of the [3H]estradiol esters biosynthesized in each. In addition, we characterized the endogenous estradiol fatty acid esters in the follicular fluid and compared them to the biosynthetic esters. The fatty acid composition of the endogenous esters was different than those synthesized by the cellular acyl coenzyme A:acyltransferase, and the same as the esters synthesized by LCAT, demonstrating that the esters are produced in situ in the follicular fluid. Although the role of these estradiol esters in the ovary is not known, given their remarkable estrogenic potency it is highly probable that they have an important physiological role.

21 CFR 175.260 - Partial phosphoric acid esters of polyester resins.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Partial phosphoric acid esters of polyester resins... of polyester resins. Partial phosphoric acid esters of polyester resins identified in this section... prescribed conditions: (a) For the purpose of this section, partial phosphoric acid esters of polyester...

Four coordination polymers based on 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers: Synthesis, luminescence detection of acetone and optical properties

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

Arıcı, Mürsel, E-mail: marici@ogu.edu.tr; Zafer Yeşilel, Okan; Büyükgüngör, Orhan

dispersed in methanol could be used as a fluorescent sensor for the detection of acetone. Moreover, thermal and optical properties of the complexes were also studied. - Highlights: • Four new 2D and 3D coordination polymers with 5-tert-butyl isophthalic acid and rigid bis(imidazol-1yl)benzene linkers. • The structural diversity depending on ligands and coordination number of metal centers. • Fluorescent sensor for the detection of acetone.« less

(E)-2′-[(3,5-Di-tert-butyl-2-hy­droxy­benzyl­idene)amino]-1,1′-binaphthalen-2-ol methanol monosolvate

PubMed Central

He, Dian; Li, Chong; Wang, Xiaohong

2011-01-01

The title compound, C35H35NO2·CH4O, was obtained by the reaction of rac-2-amino-2-hy­droxy-1,1-binaphthyl and 3,5-di-tert-butyl-2-hy­droxy­benzaldehyde in absolute methanol. In the Schiff base mol­ecule, the two naphthyl bicycles are twisted by 71.15 (5)°. One hy­droxy group is involved in intra­molecular O—H⋯N hydrogen bond, while the methanol solvent mol­ecule is linked to another hy­droxy group via an inter­molecular O—H⋯O hydrogen bond. PMID:22219946

Protective Effects of Black Rice Extracts on Oxidative Stress Induced by tert-Butyl Hydroperoxide in HepG2 Cells

PubMed Central

Lee, Seon-Mi; Choi, Youngmin; Sung, Jeehye; Kim, Younghwa; Jeong, Heon-Sang; Lee, Junsoo

2014-01-01

Black rice contains many biologically active compounds. The aim of this study was to investigate the protective effects of black rice extracts (whole grain extract, WGE and rice bran extract, RBE) on tert-butyl hydroperoxide (TBHP)-induced oxidative injury in HepG2 cells. Cellular reactive oxygen species (ROS), antioxidant enzyme activities, malondialdehyde (MDA) and glutathione (GSH) concentrations were evaluated as biomarkers of cellular oxidative status. Cells pretreated with 50 and 100 μg/mL of WGE or RBE were more resistant to oxidative stress in a dose-dependent manner. The highest WGE and BRE concentrations enhanced GSH concentrations and modulated antioxidant enzyme activities (glutathione reductase, glutathione-S-transferase, catalase, and superoxide dismutase) compared to TBHP-treated cells. Cells treated with RBE showed higher protective effect compared to cells treated with WGE against oxidative insult. Black rice extracts attenuated oxidative insult by inhibiting cellular ROS and MDA increase and by modulating antioxidant enzyme activities in HepG2 cells. PMID:25580401

[18F]Fluorophenylazocarboxylates: Design and Synthesis of Potential Radioligands for Dopamine D3 and μ-Opioid Receptor

PubMed Central

2017-01-01

18F-Labeled building blocks from the type of [18F]fluorophenylazocarboxylic-tert-butyl esters offer a rapid, mild, and reliable method for the 18F-fluoroarylation of biomolecules. Two series of azocarboxamides were synthesized as potential radioligands for dopamine D3 and the μ-opioid receptor, revealing compounds 3d and 3e with single-digit and sub-nanomolar affinity for the D3 receptor and compound 4c with only micromolar affinity for the μ-opioid receptor, but enhanced selectivity for the μ-subtype in comparison to the lead compound AH-7921. A “minimalist procedure” without the use of a cryptand and base for the preparation of 4-[18F]fluorophenylazocarboxylic-tert-butyl ester [18F]2a was established, together with the radiosynthesis of methyl-, methoxy-, and phenyl-substituted derivatives ([18F]2b–f). With the substituted [18F]fluorophenylazocarbylates in hand, two prototype azocarboxylates radioligands were synthesized by 18F-fluoroarylation, namely the methoxy azocarboxamide [18F]3d as the D3 receptor radioligand and [18F]4a as a prototype structure of the μ-opioid receptor radioligand. By introducing the new series of [18F]fluorophenylazocarboxylic-tert-butyl esters, the method of 18F-fluoroarylation was significantly expanded, thereby demonstrating the versatility of 18F-labeled phenylazocarboxylates for the design of potential radiotracers for positron emission tomography . PMID:29479577

Some features of the oxidative conversion of Mo(CO)/sub 6/ in a medium of hydroperoxide or tert-butyl hydroperoxide and an aromatic hydrocarbon

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

Fomin, V.M.; Lunin, A.V.; Aleksandrov, Yu.A.

1988-03-10

Occurrence of the reaction under study was followed from the decrease in hydroperoxide or of Mo(CO)/sub 6/. The Mo(CO)/sub 6/ content of the reaction was found by determining either the concentration of this compound directly or by determining the concentration of the gaseous products from its transformations (CO + CO/sub 2/). Hydroperoxides (I) and (II) were determined iodometrically. Metal-containing products of the oxidation of Mo(CO)/sub 6/, molybdenum oxides and peroxides, were analyzed by IR and ESR spectroscopy, elemental analysis, and iodometry. Analysis of transformation products of the hydroperoxides (phenol, acetone, dimethylphenylcarbinol, acetophenone, tert-butyl alcohol, water, and oxygen) was performed usingmore » gas chromatography. Results are presented.« less

Method for separating mono- and di-octylphenyl phosphoric acid esters

DOEpatents

Arnold, Jr., Wesley D.

1977-01-01

A method for separating mono-octylphenyl phosphoric acid ester and di-octylphenyl phosphoric acid ester from a mixture thereof comprises reacting the ester mixture with a source of lithium or sodium ions to form a mixture of the phosphate salts; contacting the salt mixture with an organic solvent which causes the dioctylphenyl phosphate salt to be dissolved in the organic solvent phase and the mono-octylphenyl phosphate salt to exist in a solid phase; separating the phases; recovering the phosphate salts from their respective phases; and acidifying the recovered salts to form the original phosphoric acid esters.

21 CFR 178.3450 - Esters of stearic and palmitic acids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... SANITIZERS Certain Adjuvants and Production Aids § 178.3450 Esters of stearic and palmitic acids. The ester...

21 CFR 178.3450 - Esters of stearic and palmitic acids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... SANITIZERS Certain Adjuvants and Production Aids § 178.3450 Esters of stearic and palmitic acids. The ester...

40 CFR 721.10412 - Phosphonic acid ester (generic) (P-07-706).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Phosphonic acid ester (generic) (P-07... Specific Chemical Substances § 721.10412 Phosphonic acid ester (generic) (P-07-706). (a) Chemical substance... phosphonic acid ester (PMN P-07-706) is subject to reporting under this section for the significant new uses...

40 CFR 721.10412 - Phosphonic acid ester (generic) (P-07-706).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Phosphonic acid ester (generic) (P-07... Specific Chemical Substances § 721.10412 Phosphonic acid ester (generic) (P-07-706). (a) Chemical substance... phosphonic acid ester (PMN P-07-706) is subject to reporting under this section for the significant new uses...

40 CFR 721.10412 - Phosphonic acid ester (generic) (P-07-706).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Phosphonic acid ester (generic) (P-07... Specific Chemical Substances § 721.10412 Phosphonic acid ester (generic) (P-07-706). (a) Chemical substance... phosphonic acid ester (PMN P-07-706) is subject to reporting under this section for the significant new uses...

Application of ethyl esters and d3-methyl esters as internal standards for the gas chromatographic quantification of transesterified fatty acid methyl esters in food.

PubMed

Thurnhofer, Saskia; Vetter, Walter

2006-05-03

Ethyl esters (FAEE) and trideuterium-labeled methyl esters (d3-FAME) of fatty acids were prepared and investigated regarding their suitability as internal standards (IS) for the determination of fatty acids as methyl esters (FAME). On CP-Sil 88, ethyl esters of odd-numbered fatty acids eluted approximately 0.5 min after the respective FAME, and only coelutions with minor FAME were observed. Depending on the problem, one or even many FAEE can be added as IS for the quantification of FAME by both GC-FID and GC-MS. By contrast, d3-FAME coeluted with FAME on the polar GC column, and the use of the former as IS requires application of GC-MS. In the SIM mode, m/z 77 and 90 are suggested for d3-methyl esters of saturated fatty acids, whereas m/z 88 and 101 are recommended for ethyl esters of saturated fatty acids. These m/z values give either no or very low response for FAME and can thus be used for the analysis of FAME in food by GC-MS in the SIM mode. Fatty acids in sunflower oil and mozzarella cheese were quantified using five saturated FAEE as IS. Gravimetric studies showed that the transesterification procedure could be carried out without of loss of fatty acids. GC-EI/MS full scan analysis was suitable for the quantitative determination of all unsaturated fatty acids in both food samples, whereas GC-EI/MS in the SIM mode was particularly valuable for quantifying minor fatty acids. The novel GC-EI/MS/SIM method using fatty acid ethyl esters as internal standards can be used to quantify individual fatty acids only, that is, without determination of all fatty acids (the common 100% method), although this is present. This was demonstrated by the exclusive quantification of selected fatty acids including methyl-branched fatty acids, erucic acid (18:1n-9trans), and polyunsaturated fatty acids in cod liver oil and goat's milk fat.

Preparation of .alpha.,.beta.-unsaturated carboxylic acids and esters

DOEpatents

Gogate, Makarand Ratnakar; Spivey, James Jerry; Zoeller, Joseph Robert

1998-01-01

Disclosed is a process for the preparation of .alpha.,.beta.-unsaturated carboxylic acids and esters thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic acid, ester or anhydride in the presence of a catalyst comprising an oxide of niobium.

Preparation of {alpha},{beta}-unsaturated carboxylic acids and esters

DOEpatents

Gogate, M.R.; Spivey, J.J.; Zoeller, J.R.

1998-09-15

Disclosed is a process for the preparation of {alpha},{beta}-unsaturated carboxylic acids and esters thereof which comprises contacting formaldehyde or a source of formaldehyde with a carboxylic acid, ester or anhydride in the presence of a catalyst comprising an oxide of niobium.

Hydrolysis of the quinone methide of butylated hydroxytoluene in aqueous solutions.

PubMed

Willcockson, Maren Gulsrud; Toteva, Maria M; Stella, Valentino J

2013-10-01

Butylated hydroxytoluene or BHT is an antioxidant commonly used in pharmaceutical formulations. BHT upon oxidation forms a quinone methide (QM). QM is a highly reactive electrophilic species that can undergo nucleophilic addition. Here, the kinetic reactivity of QM with water at various apparent pH values in a 50% (v/v) water-acetonitrile solution at constant ionic strength of I = 0.5 (NaCl)4 , was studied. The hydrolysis of QM in the presence of added acid, base, sodium chloride, and phosphate buffer resulted in the formation of only one product--the corresponding 3,5-di-tert-butyl-4-hydroxybenzyl alcohol (BA). The rate of BA formation was catalyzed by the addition of acid and base, but not chloride and phosphate species. Nucleophilic excipients, used in the pharmaceutical formulation, or nucleophilic groups on active pharmaceutical ingredient molecule may form adducts with QM, the immediate oxidative product of BHT degradation, thus having implications for drug product impurity profiles. Because of these considerations, BHT should be used with caution in formulations containing drugs or excipients capable of acting as nucleophiles. © 2013 Wiley Periodicals, Inc. and the American Pharmacists Association.

The application of silicalite-1/fly ash cenosphere (S/FAC) zeolite composite for the adsorption of methyl tert-butyl ether (MTBE).

PubMed

Lu, Jia; Xu, Fang; Wang, Deju; Huang, Jue; Cai, Weimin

2009-06-15

Silicalite-1/fly ash cenosphere (S/FAC) zeolite composite has been applied for batch adsorption of methyl tert-butyl ether (MTBE) from water systems. Here the key experimental conditions, including the ratio of initial MTBE concentration to the amount weight of S/FAC, adsorption time and temperature, have been discussed in detail. The results show that approximately 93-95% MTBE could be adsorbed with initial concentration of MTBE solution 1000 microg l(-1). The column flow-through experiments also prove the high capacity of S/FAC composite for MTBE removal. The distinct advantages of S/FAC zeolite composite as adsorbent lie in (1) enhanced adsorption rate and capacity based on hierarchical micro and meso/macroporosity of S/FAC; (2) more easily operation and recycling process by assembly of nano-sized silicalite-1 zeolite on FAC support.

Ionic-liquid-mediated poly(dimethylsiloxane)- grafted carbon nanotube fiber prepared by the sol-gel technique for the head space solid-phase microextraction of methyl tert-butyl ether using GC.

PubMed

Vatani, Hossein; Yazdi, Ali Sarafraz

2014-01-01

A headspace solid-phase microextraction method was developed for the preconcentration and extraction of methyl tert-butyl ether. An ionic-liquid-mediated multiwalled carbon nanotube-poly(dimethylsiloxane) hybrid coating, which was prepared by covalent functionalization of multiwalled carbon nanotubes with hydroxyl-terminated poly(dimethylsiloxane) using the sol-gel technique, was used as solid-phase microextraction adsorbent. This innovative fiber exhibited a highly porous surface structure, high thermal stability (at least 320°C) and long lifespan (over 210 uses). Potential factors affecting the extraction efficiency were optimized. Under the optimum conditions, the method LOD (S/N = 3) was 0.007 ng/mL and the LOQ (S/N = 10) was 0.03 ng/mL. The calibration curve was linear in the range of 0.03-200 ng/mL. The RSDs for one fiber (repeatability, n = 5) at three different concentrations (0.05, 1, and 150 ng/mL) were 5.1, 4.2, and 4.6% and for the fibers obtained from different batches (reproducibility, n = 3) were 6.5, 5.9, and 6.3%, respectively. The developed method was successfully applied to the determination of methyl tert-butyl ether in different real water samples on three consecutive days. The relative recoveries for the spiked samples with 0.05, 1, and 150 ng/mL were between 94-104%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Depigmentation with tert-butyl hydroquinone using black guinea pigs.

PubMed

Patrick, E; Juberg, D R; O'Donoghue, J; Maibach, H I

1999-01-01

tert-Butyl hydroquinone (TBHQ) has important and functional uses in consumer and commercial applications, some of which involve human exposure primarily through dermal contact. To assist in the safety evaluation of TBHQ, this study was conducted to determine whether TBHQ would produce changes in skin pigmentation after repeated dermal application to black guinea pigs. Hydroquinone (HQ) and hydroquinone monomethyl ether (HQMME) were used as positive controls. TBHQ and HQ were tested at concentrations of 0.1, 1.0 and 5.0%, while HQMME was tested at a concentration of 10.0%. Groups of five males and five females were dosed with TBHQ, HQ, or the vehicle (hydrophilic ointment) daily (M-F) for 13 weeks. In addition, animals (five males, five females) treated with HQMME received 13 doses over a 3-week period. The application site was evaluated weekly for degree of pigmentation loss and irritation. Twenty-four hours after final application, sites were evaluated for depigmentation, irritation and hyperpigmentation. Subsequently, the application site was depilated and re-evaluated for the same endpoints. Repetitive exposure to concentrations of 1.0% and 5.0% TBHQ and HQ were slightly to moderately irritating, while 0.1% of each of these test materials produced only weak irritant responses. No irritant responses to hydrophilic ointment were observed and HQMME produced weak irritant responses after 2 weeks. Neither 0.1% TBHQ nor HQ produced depigmentation, while 20% of animals dosed with 1.0% TBHQ and 30% of animals dosed with 1.0% HQ had spotty or uniform loss of pigment at the site of treatment. Approximately 40% of animals dosed with 5% TBHQ or HQ were depigmented at the treatment site at the final evaluation. HQMME produced complete depigmentation of the skin and hair in all animals. Hyperpigmentation of the treatment site was observed in 80-100% of animals in all groups (with the exception of HQMME-treated animals, treated for only 3 weeks), which may be attributable to

Stereoselective Formation of Trisubstituted Vinyl Boronate Esters by the Acid-Mediated Elimination of α-Hydroxyboronate Esters

PubMed Central

2015-01-01

The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the (Z)-olefin isomer, which was established by subjecting the products to a Suzuki–Miyaura coupling reaction to obtain alkenes of known geometry. PMID:24915498

Gallic acid-based alkyl esters synthesis in a water-free system by celite-bound lipase of Bacillus licheniformis SCD11501.

PubMed

Sharma, Shivika; Kanwar, Shamsher S; Dogra, Priyanka; Chauhan, Ghanshyam S

2015-01-01

Gallic acid (3, 4, 5- trihydroxybenzoic acid) is an important antioxidant, anti-inflammatory, and radical scavenging agent. In the present study, a purified thermo-tolerant extra-cellular lipase of Bacillus licheniformis SCD11501 was successfully immobilized by adsorption on Celite 545 gel matrix followed by treatment with a cross-linking agent, glutaraldehyde. The celite-bound lipase treated with glutaraldehyde showed 94.8% binding/retention of enzyme activity (36 U/g; specific activity 16.8 U/g matrix; relative increase in enzyme activity 64.7%) while untreated matrix resulted in 88.1% binding/retention (28.0 U/g matrix; specific activity 8.5 U/g matrix) of lipase. The celite-bound lipase was successfully used to synthesis methyl gallate (58.2%), ethyl gallate (66.9%), n-propyl gallate (72.1%), and n-butyl gallate (63.8%) at 55(o) C in 10 h under shaking (150 g) in a water-free system by sequentially optimizing various reaction parameters. The low conversion of more polar alcohols such as methanol and ethanol into their respective gallate esters might be due to the ability of these alcohols to severely remove water from the protein hydration shell, leading to enzyme inactivation. Molecular sieves added to the reaction mixture resulted in enhanced yield of the alkyl ester(s). The characterization of synthesised esters was done through fourier transform infrared (FTIR) spectroscopy and (1) H NMR spectrum analysis. © 2015 American Institute of Chemical Engineers.

IRIS Toxicological Review of tert-Butyl Alcohol (tert-Butanol) ...

EPA Pesticide Factsheets

In August 2013, EPA released the draft literature searches and associated search strategies, evidence tables, and exposure response arrays for TBA to obtain input from stakeholders and the public prior to developing the draft IRIS assessment. Specifically, EPA was interested in comments on the following: Draft literature search strategies The approach for identifying studies The screening process for selecting pertinent studies The resulting list of pertinent studies Preliminary evidence tables The process for selecting studies to include in evidence tables The quality of the studies in the evidence tables The literature search strategy, which describes the processes for identifying scientific literature, contains the studies that EPA considered and selected to include in the evidence tables. The preliminary evidence tables and exposure-response arrays present the key study data in a standardized format. The evidence tables summarize the available critical scientific literature. The exposure-response figures provide a graphical representation of the responses at different levels of exposure for each study in the evidence table. EPA is undertaking a new health assessment for t-butyl alcohol (TBA) for the Integrated Risk Information System (IRIS). The outcome of this project will be a Toxicological Review and IRIS and IRIS Summary of TBA that will be entered on the IRIS database. IRIS is an EPA da

Antichaperone activity and heme degradation effect of methyl tert-butyl ether (MTBE) on normal and diabetic hemoglobins.

PubMed

Najdegerami, Ismaeil Hossein; Maghami, Parvaneh; Sheikh-Hasani, Vahid; Hosseinzadeh, Ghader; Sheibani, Nader; Moosavi-Movahedi, Ali A

2017-05-01

Because of the extensive use of methyl tert-butyl ether (MTBE) as an additive to increase the octane quality of gasoline, the environmental pollution by this compound has increased in recent decades. Environmental release of MTBE may lead to its entry to the blood stream through inhalation or drinking of contaminated water, and its interactions with biological molecules such as proteins. The present study was proposed to comparatively investigate the interactions of MTBE with hemoglobin (Hb) from diabetic and nondiabetic individuals using various spectroscopic methods including UV-visible, fluorescence, chemiluminescence, and circular dichroism. These results demonstrated the effects of MTBE on heme degradation of Hb and the reaction of these degradation products with water generating reactive oxygen species. Interaction of Hb with MTBE enhanced its aggregation rate and decreased lag time, indicating the antichaperone activity of MTBE upon interaction with Hb. Furthermore, the diabetic Hb showed more severe effects of MTBE, including heme degradation, reactive oxygen species production, unfolding, and antichaperone behavior than the nondiabetic Hb. The results from molecular docking suggested that the special interaction site of MTBE in the vicinity of Hb heme group is responsible for heme degradation. Copyright © 2016 John Wiley & Sons, Ltd.

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

40 CFR 721.6110 - Alkyldi(alkyloxyhydroxypropyl) derivative, phosphoric acid esters, potassium salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

...) derivative, phosphoric acid esters, potassium salts. 721.6110 Section 721.6110 Protection of Environment...) derivative, phosphoric acid esters, potassium salts. (a) Chemical substance and significant new uses subject...) derivative, phosphoric acid esters, potassium salts (PMN P-91-818) is subject to reporting under this section...

Cyclic cooperative intramolecular hydrogen bond in p-tert-butylcalix[6]arene according to FTIR spectroscopy and DFT studies

NASA Astrophysics Data System (ADS)

Furer, V. L.; Potapova, L. I.; Kovalenko, V. I.

2017-06-01

This article describes a comparative research of IR spectra and H-bonds in the p-tert-butylcalix[6]arene (TB6) and calix[6]arene (C6). IR spectra were computed for compressed cone conformation by DFT method. The assignment of the bands in the IR spectra of the TB6 and C6 was made. The effect of the bulky tert-butyl substituents on the structure and H-bonding in TB6 was established. Our research has shown that in TB6 and C6 the cyclic H-bond is realized, which ensures the existence of a compressed cone conformation. Introduction of tert-butyl substituents in TB6 leads to hardening of H-bonds. Examination of IR spectra showed that when heated TB6 remains in a compressed cone conformation. In a molecule of TB6 and C6 oxygen atoms are in a ;boat; conformation.

Crystal structure of 1-iodo-3-{[4-(tert-butyl­sulfan­yl)phen­yl]ethyn­yl}azulene

PubMed Central

Förster, Sebastian; Seichter, Wilhelm; Weber, Edwin

2015-01-01

The title compound, C20H19IS, features a 1,3-disubstituted azulene involving an ethynylene elongated 4-(tert-butyl­sulfanyl)­phenyl sidearm and an iodine atom as the substituents. The azulene ring system is almost planar (r.m.s. deviation = 0.012 Å) and subtends a dihedral angle of 35.7 (1)° with the benzene ring. As a result of the inherent dipole character of the azulene core, a supra­molecular π–π dimer [separation between the centroids of the five- and seven-membered rings = 3.7632 (10) Å] with anti­parallel orientated mol­ecules can be observed in the crystal. The packing is consolidated by an unusual I⋯π(acetyl­ene) contact [I⋯Cg = 3.34 Å, C—I⋯Cg = 173.3°], and a very weak C—H⋯π inter­action is also found in the structure, with the azulene five-membered ring as the acceptor. PMID:26396788

Improving the Safety of Lithium-Ion Battery via a Redox Shuttle Additive 2,5-Di- tert-butyl-1,4-bis(2-methoxyethoxy)benzene (DBBB).

PubMed

Leonet, Olatz; Colmenares, Luis C; Kvasha, Andriy; Oyarbide, Mikel; Mainar, Aroa R; Glossmann, Tobias; Blázquez, J Alberto; Zhang, Zhengcheng

2018-03-21

2,5-Di- tert-butyl-1,4-bis(2-methoxyethoxy)benzene (DBBB) is studied as a redox shuttle additive for overcharge protection for a 1.5 Ah graphite/C-LFP lithium-ion pouch cell for the first time. The electrochemical performance demonstrated that the protecting additive remains inert during the extended standard cycling for 4000 cycles. When a 100% overcharge is introduced in the charging protocol, the baseline cell fails rapidly during the first abusive event, whereas the cell containing DBBB additive withstands 700 overcharge cycles with 87% capacity retention and no gas evolution or cell swelling was observed. It is the first time the effectiveness of the DBBB as overcharge protection additive in a large pouch cell format is demonstrated.

Protective effect of ganodermanondiol isolated from the Lingzhi mushroom against tert-butyl hydroperoxide-induced hepatotoxicity through Nrf2-mediated antioxidant enzymes.

PubMed

Li, Bin; Lee, Dong-Sung; Kang, Yue; Yao, Nai-Qi; An, Ren-Bo; Kim, Youn-Chul

2013-03-01

Ganodermanondiol, a biologically active compound, was isolated from the Lingzhi mushroom (Ganoderma lucidum). The present study examined the protective effects of ganodermanondiol against tert-butyl hydroperoxide (t-BHP)-induced hepatotoxicity. Ganodermanondiol protected human liver-derived HepG2 cells through nuclear factor-E2-related factor 2 (Nrf2) pathway-dependent heme oxygenase-1 expressions. Moreover, ganodermanondiol increased cellular glutathione levels and the expression of the glutamine-cysteine ligase gene in a dose-dependent manner. Furthermore, ganodermanondiol exposure enhanced the phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and its upstream kinase activators, LKB1 and Ca(2+)/calmodulin-dependent protein kinase-II (CaMKII). This study indicates that ganodermanondiol exhibits potent cytoprotective effects on t-BHP-induced hepatotoxicity in human liver-derived HepG2 cells, presumably through Nrf2-mediated antioxidant enzymes and AMPK. Copyright © 2012 Elsevier Ltd. All rights reserved.

Catalytic Activity of μ-Carbido-Dimeric Iron(IV) Octapropylporphyrazinate in the 3,5,7,2',4'-Pentahydroxyflavone Oxidation Reaction with tert-Butyl Hydroperoxide

NASA Astrophysics Data System (ADS)

Tyurin, D. V.; Zaitseva, S. V.; Kudrik, E. V.

2018-05-01

It is found for the first time that μ-carbido-dimeric iron(IV) octapropylporphyrazinate displays catalytic activity in the oxidation reaction of natural flavonol morin with tert-butyl hydroperoxide, with the catalyst being stable under conditions of the reaction. The kinetics of this reaction are studied. It is shown the reaction proceeds via tentative formation of a complex between the catalyst and the oxidant, followed by O‒O bond homolytic cleavage. The kinetics of the reaction is described in the coordinates of the Michaelis-Menten equation. A linear dependence of the apparent reaction rate constant on the concentration of the catalyst is observed, testifying to its participation in the limiting reaction step. The equilibrium constants and rates of interaction are found. A mechanism is proposed for the reaction on the basis of the experimental data.

Environmental and Chemical Aging of Fatty-Acid-Based Vinyl Ester Composites

DTIC Science & Technology

2011-04-01

Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites by Steven E. Boyd and John J. La Scala ARL-TR-5523 April...2011 Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites Steven E. Boyd and John J. La Scala Weapons and Materials...COVERED (From - To) October 2009–September 2010 4. TITLE AND SUBTITLE Environmental and Chemical Aging of Fatty- Acid -Based Vinyl Ester Composites

Modular syntheses of H₄octapa and H₂dedpa, and yttrium coordination chemistry relevant to ⁸⁶Y/⁹⁰Y radiopharmaceuticals.

PubMed

Price, Eric W; Cawthray, Jacqueline F; Adam, Michael J; Orvig, Chris

2014-05-21

The ligands H2dedpa, H4octapa, p-SCN-Bn-H2dedpa, and p-SCN-Bn-H4octapa were synthesized using a new protection chemistry approach, with labile tert-butyl esters replacing the previously used methyl esters as protecting groups for picolinic acid moieties. Additionally, the ligands H2dedpa and p-SCN-Bn-H2dedpa were synthesized using nosyl protection chemistry for the first time. The use of tert-butyl esters allows for deprotection at room temperature in trifluoroacetic acid (TFA), which compares favorably to the harsh conditions of refluxing HCl (6 M) or LiOH that were previously required for methyl ester cleavage. H4octapa has recently been shown to be a very promising (111)In and (177)Lu ligand for radiopharmaceutical applications; therefore, coordination chemistry studies with Y(3+) are described to assess its potential for use with (86)Y/(90)Y. The solution chemistry of H4octapa with Y(3+) is shown to be suitable via solution NMR studies of the [Y(octapa)](-) complex and density functional theory (DFT) calculations of the predicted structure, suggesting properties similar to those of the analogous In(3+) and Lu(3+) complexes. The molecular electrostatic potential (MEP) was mapped onto the molecular surface of the DFT-calculated coordination structures, suggesting very similar and even charge distributions between both the Lu(3+) and Y(3+) complexes of octapa(4-), and coordinate structures between 8 (ligand only) and 9 (ligand and one H2O). Potentiometric titrations determined H4octapa to have a formation constant (log K(ML)) with Y(3+) of 18.3 ± 0.1, revealing high thermodynamic stability. This preliminary work suggests that H4octapa may be a competent ligand for future (86)Y/(90)Y radiopharmaceutical applications.

Carbodithioic acid esters of fluoxetine, a novel class of dual-function spermicides.

PubMed

Kiran Kumar, S T V S; Kumar, Lalit; Sharma, Vishnu L; Jain, Ashish; Jain, Rajeev K; Maikhuri, Jagdamba P; Kumar, Manish; Shukla, Praveen K; Gupta, Gopal

2008-10-01

Carbodithioic acid esters of fluoxetine have been prepared by replacing the methylamino function in aminopropane chain with carbodithioic acid ester group and by adding various S-2-hydroxypropyl ester of dialkyl carbodithioic acid at 3-methylamino group. Some of these compounds showed spermicidal, antifungal and anti-Trichomonas activities. The study revealed that incorporation of carbodithioic acid residue directly into fluoxetine structure leads to compounds with better antifungal and anti-Trichomonas activities, and N-methyl-[3-phenyl-3-(4-trifluoromethyl-phenoxy)-propyl]carbodithioic acid S-(2-pyrrolidino-ethyl) ester (14) has shown better profile than both fluoxetine and nonoxynol-9. Further lead optimization may yield a potent dual-function spermicide.

Gabapentin-base synthesis and theoretical studies of biologically active compounds: N-cyclohexyl-3-oxo-2-(3-oxo-2-azaspiro[4.5] decan-2-yl)-3-arylpropanamides and N-(tert-butyl)-2-(3-oxo-2-azaspiro[4.5]decan-2-yl)-2-arylacetamide derivatives

NASA Astrophysics Data System (ADS)

Amirani Poor, Mahboobe; Darehkordi, Ali; Anary-Abbasinejad, Mohammad; Mohammadi, Marziyeh

2018-01-01

An intermolecular Ugi reaction of 2-(1-(aminomethyl)cyclohexyl)acetic acid (gabapentin) with glyoxal and cyclohexyl isocyanide or aromatic aldehyde and tertbutyl isocyanide under mild conditions in ethanol have been developed to produce two novel class of N-cyclohexyl-3-(aryl)-3-oxo-2-(3-oxo-2-azaspiro[4.5]decan-2-yl)propanamideins and N-(tert-butyl)-2-(3-oxo-2-azaspiro[4.5]decan-2-yl)-2-arylacetamide derivatives in good to excellent yields. This presents the first report for the intermolecular Ugi three component reaction of gabapentin, glyoxal, and an isocyanide. Also according to the theoretical studies the electron-donating groups increase the strength of intramolecular hydrogen bond and electron-withdrawing groups decrease the strength of intramolecular hydrogen bond.

40 CFR 721.2900 - Substituted aminobenzoic acid ester (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Substituted aminobenzoic acid ester... Specific Chemical Substances § 721.2900 Substituted aminobenzoic acid ester (generic name). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance substituted aminobenzoic...

Complexes of polyadenylic acid and the methyl esters of amino acids

NASA Technical Reports Server (NTRS)

Khaled, M. A.; Mulins, D. W., Jr.; Swindle, M.; Lacey, J. C., Jr.

1983-01-01

A study of amino acid methyl esters binding to polyadenylic acid supports the theory that the genetic code originated through weak but selective affinities between amino acids and nucleotides. NMR, insoluble complex analysis, and ultraviolet spectroscopy are used to illustrate a correlation between the hydrophybicities of A amino acids and their binding constants, which, beginning with the largest, are in the order of Phe (having nominally a hydrophobic AAA anticodon), Ile, Leu, Val and Gly (having a hydrophilic anticodon with no A). In general, the binding constants are twice the values by Reuben and Polk (1980) for monomeric AMP, which suggests that polymer amino acids are interacting with only one base. No real differences are found betwen poly A binding for free Phe, Phe methyl ester or Phe amide, except that the amide value is slightly lower.

Affinity labelling enzymes with esters of aromatic sulfonic acids

DOEpatents

Wong, Show-Chu; Shaw, Elliott

1977-01-01

Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

Sugar fatty acid esters inhibit biofilm formation by food-borne pathogenic bacteria

PubMed Central

Furukawa, Soichi; Akiyoshi, Yuko; O’Toole, George A.; Ogihara, Hirokazu; Morinaga, Yasushi

2010-01-01

Effects of food additives on biofilm formation by food-borne pathogenic bacteria were investigated. Thirty-three potential food additives and 3 related compounds were added to the culture medium at concentrations from 0.001 to 0.1% (w/w), followed by inoculation and cultivation of five biofilm-forming bacterial strains for the evaluation of biofilm formation. Among the tested food additives, 21 showed inhibitory effects of biofilm formation by Staphylococcus aureus and Escherichia coli, and in particular, sugar fatty acid esters showed significant anti-biofilm activity. Sugar fatty acid esters with long chain fatty acid residues (C14-16) exerted their inhibitory effect at the concentration of 0.001%(w/w), but bacterial growth was not affected at this low concentration. Activities of the sugar fatty acid esters positively correlated with the increase of the chain length of the fatty acid residues. Sugar fatty acid esters inhibited the initial attachment of the Staphylococcus aureus cells to the abiotic surface. Sugar fatty acid esters with long chain fatty acid residues (C14-16) also inhibited biofilm formation by Streptococcus mutans and Listeria monocytogenes at 0.01%(w/w), while the inhibition of biofilm formation by Pseudomonas aeruginosa required the addition of a far higher concentration (0.1%(w/w)) of the sugar fatty acid esters. PMID:20089325

Simultaneous analysis of free phytosterols/phytostanols and intact phytosteryl/phytostanyl fatty acid and phenolic acid esters in cereals.

PubMed

Esche, Rebecca; Barnsteiner, Andreas; Scholz, Birgit; Engel, Karl-Heinz

2012-05-30

An approach based on solid-phase extraction for the effective separation of free phytosterols/phytostanols and phytosteryl/phytostanyl fatty acid and phenolic acid esters from cereal lipids was developed. The ester conjugates were analyzed in their intact form by means of capillary gas chromatography. Besides free sterols and stanols, up to 33 different fatty acid and phenolic acid esters were identified in four different cereal grains via gas chromatography-mass spectrometry. The majority (52-57%) of the sterols and stanols were present as fatty acid esters. The highest levels of all three sterol and stanol classes based on dry matter of ground kernels were determined in corn, whereas the oil extract of rye was 1.7 and 1.6 times richer in fatty acid esters and free sterols/stanols than the corn oil. The results showed that there are considerable differences in the sterols/stanols and their ester profiles and contents obtained from corn compared to rye, wheat, and spelt. The proposed method is useful for the quantification of a wide range of free phytosterols/phytostanols and intact phytosteryl/phytostanyl esters to characterize different types of grain.

Effects on temperature and acidic pre-treatment on Fenton-driven oxidation of MTBE-spent granular activated carbon

EPA Science Inventory

Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the p...

Bis[μ-N-(tert-butyl­dimethyl­silyl)-N-(pyridin-2-ylmeth­yl)amido]­bis­[methyl­cobalt(II)

PubMed Central

Malassa, Astrid; Agthe, Christine; Görls, Helmar; Westerhausen, Matthias

2012-01-01

The green title complex, [Co2(CH3)2(C12H21N2Si)2], was obtained from bis­{[μ-N-tert-butyl­dimethyl­silyl-N-(pyridin-2-ylmeth­yl)amido]­chloridocobalt(II)} and methyl­lithium in diethyl ether at 195 K via a metathesis reaction. The dimeric cobalt(II) complex exhibits a crystallographic center of inversion in the middle of the Co2N2 ring (average Co—N = 2.050 Å). The CoII atom shows a distorted tetra­hedral coordination sphere. The exocyclic Co—N bond length to the pyridyl group shows a similar value of 2.045 (4) Å. The exocyclic methyl group has a rather long Co—C bond length of 2.019 (5) Å. PMID:22969464

Synthesis, structural characterization and theoretical studies of a new Schiff base 4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl) imino)methyl)phenol

NASA Astrophysics Data System (ADS)

Cuenú, Fernando; Londoño-Salazar, Jennifer; Torres, John Eduard; Abonia, Rodrigo; D'Vries, Richard F.

2018-01-01

4-(((3-(tert-Butyl)-(1-phenyl)pyrazol-5-yl)imino)methyl)phenol (4-OHFPz) was synthesized and characterized by FT-IR, MS, NMR, and single-crystal X-ray diffraction. Optimization of molecular geometry, vibrational frequencies, and chemical shifts were calculated by using the methods of density functional theory (DFT) with B3LYP and B3PW91 as functionals and Hartree-Fock with 6-311G++(d,p) as basis set using the GAUSSIAN 09 program package. With the VEDA 4 software, the vibrational frequencies were assigned in terms of the potential energy distribution (PED). The equilibrium geometries calculated by all methods were compared with X-ray diffraction results, indicating that the theoretical results matches well with the experimental ones. The data obtained from the vibrational analysis and the calculated NMR are consistent with the experimental spectra.

Occurrence of phthalic acid esters in source waters: a nationwide survey in China during the period of 2009-2012.

PubMed

Liu, Xiaowei; Shi, Jianghong; Bo, Ting; Zhang, Hui; Wu, Wei; Chen, Qingcai; Zhan, Xinmin

2014-01-01

The first nationwide survey of six phthalic acid esters (PAEs) (diethyl phthalate (DEP); dimethyl phthalate (DMP); di-n-butyl phthalate (DBP); butyl benzyl phthalate (BBP); bis(2-ethylhexyl) phthalate (DEHP); di-n-octyl phthalate (DnOP)) in source waters was conducted in China. The results showed these PAEs were ubiquitous in source waters. DBP and DEHP were the most frequently detected with high concentrations ranging nd-1.52 μg/L and nd-6.35 μg/L, respectively. These PAEs concentrations (except DBP) in surface water (rivers, lakes and reservoirs) were generally higher than those in groundwater; DBP had high concentrations in groundwater in Northeast China (Liao River Basin) and North China (Hai River Basin). Their concentrations in the northern regions were generally higher than those in the southern and eastern regions; particularly, in North China. Three short-chain PAEs (DMP, DEP and DBP) were detected with high concentrations in Hai River Basin, Pearl River Basin and Yellow River Basin. Copyright © 2013 Elsevier Ltd. All rights reserved.

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Lactylated fatty acid esters of glycerol and... DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and...

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Lactylated fatty acid esters of glycerol and... DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and...

Methods of refining and producing dibasic esters and acids from natural oil feedstocks

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

Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

Methods and systems for making dibasic esters and/or dibasic acids using metathesis are generally disclosed. In some embodiments, the methods comprise reacting a terminal olefin ester with an internal olefin ester in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In some embodiments, the terminal olefin ester or the internal olefin ester are derived from a renewable feedstock, such as a natural oil feedstock. In some such embodiments, the natural oil feedstock, or a transesterified derivative thereof, is metathesized to make the terminal olefin ester or the internal olefin ester.

Poly(Acrylic Acid-b-Styrene) Amphiphilic Multiblock Copolymers as Building Blocks for the Assembly of Discrete Nanoparticles

PubMed Central

Greene, Anna C.; Zhu, Jiahua; Pochan, Darrin J.; Jia, Xinqiao; Kiick, Kristi L.

2011-01-01

In order to expand the utility of current polymeric micellar systems, we have developed amphiphilic multiblock copolymers containing alternating blocks of poly(acrylic acid) and poly(styrene). Heterotelechelic poly(tert-butyl acrylate-b-styrene) diblock copolymers containing an α-alkyne and an ω-azide were synthesized by atom transfer radical polymerization (ATRP), allowing control over the molecular weight while maintaining narrow polydispersity indices. The multiblock copolymers were constructed by copper-catalyzed azide-alkyne cycloaddition of azide-alkyne end functional diblock copolymers which were then characterized by 1H NMR, FT-IR and SEC. The tert-butyl moieties of the poly(tert-butyl acrylate-b-styrene) multiblock copolymers were easily removed to form the poly(acrylic acid-b-styrene) multiblock copolymer ((PAA-PS)9), which contained up to 9 diblock repeats. The amphiphilic multiblock (PAA-PS)9 (Mn = 73.3 kg/mol) was self-assembled by dissolution into tetrahydrofuran and extensive dialysis against deionized water for 4 days. The critical micelle concentration (CMC) for (PAA-PS)9 was determined by fluorescence spectroscopy using pyrene as a fluorescent probe and was found to be very low at 2 × 10-4 mg/mL. The (PAA-PS)9 multiblock was also analyzed by dynamic light scattering (DLS) and transmission electron microscopy (TEM). The hydrodynamic diameter of the particles was found to be 11 nm. Discrete spherical particles were observed by TEM with an average particle diameter of 14 nm. The poly(acrylic acid) periphery of the spherical particles should allow for future conjugation of biomolecules. PMID:21552373

Difunctionalization of alkenes with iodine and tert-butyl hydroperoxide (TBHP) at room temperature for the synthesis of 1-(tert-butylperoxy)-2-iodoethanes.

PubMed

Wang, Hao; Chen, Cui; Liu, Weibing; Zhu, Zhibo

2017-01-01

We developed a direct vicinal difunctionalization of alkenes with iodine and TBHP at room temperature. This iodination and peroxidation in a one-pot synthesis produces 1-( tert -butylperoxy)-2-iodoethanes, which are inaccessible through conventional synthetic methods. This method generates multiple radical intermediates in situ and has excellent regioselectivity, a broad substrate scope and mild conditions. The iodine and peroxide groups of 1-( tert -butylperoxy)-2-iodoethanes have several potential applications and allow further chemical modifications, enabling the preparation of synthetically valuable molecules.

Effects of Temperature and Acidic Pre-Treatment on Fenton-Driven Oxidation of MTBE-Spent Granular Activated Carbon

EPA Science Inventory

Temperature-dependent mechanisms in the Fenton-driven chemical oxidation of methyl tert-butyl ether (MTBE)-spent granular activated carbon (GAC) was investigated. Prior to iron (Fe) amendment to the GAC, acid-treatment altered the surface chemistry of the GAC and lowered the pH ...

40 CFR 721.3800 - Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

Code of Federal Regulations, 2010 CFR

2010-07-01

... polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. 721.3800 Section 721.3800... Formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene oxide adduct. (a... generically as formaldehyde, condensated polyoxyethylene fatty acid, ester with styrenated phenol, ethylene...

Vibrational frequency analysis, FT-IR, DFT and M06-2X studies on tert-Butyl N-(thiophen-2yl)carbamate

NASA Astrophysics Data System (ADS)

Sert, Yusuf; Singer, L. M.; Findlater, M.; Doğan, Hatice; Çırak, Ç.

2014-07-01

In this study, the experimental and theoretical vibrational frequencies of a newly synthesized tert-Butyl N-(thiophen-2yl)carbamate have been investigated. The experimental FT-IR (4000-400 cm-1) spectrum of the molecule in the solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and DFT/M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with the 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The vibrational frequencies have been assigned using potential energy distribution (PED) analysis by using VEDA 4 software. The computational optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with related literature results. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and are depicted.

Encapsulating fatty acid esters of bioactive compounds in starch

NASA Astrophysics Data System (ADS)

Lay Ma, Ursula Vanesa

Interest in the use of many bioactive compounds in foods is growing in large part because of the apparent health benefits of these molecules. However, many of these compounds can be easily degraded during processing, storage, or their passage through the gastrointestinal tract before reaching the target site. In addition, they can be bitter, acrid, or astringent, which may negatively affect the sensory properties of the product. Encapsulation of these molecules may increase their stability during processing, storage, and in the gastrointestinal tract, while providing controlled release properties. The ability of amylose to form inclusion complexes and spherulites while entrapping certain compounds has been suggested as a potential method for encapsulation of certain molecules. However, complex formation and spherulitic crystallization are greatly affected by the type of inclusion molecules, type of starch, and processing conditions. The objectives of the present investigation were to: (a) study the effect of amylose, amylopectin, and intermediate material on spherulite formation and its microstructure; (b) investigate the formation of amylose and high amylose starch inclusion complexes with ascorbyl palmitate, retinyl palmitate, and phytosterol esters; (c) evaluate the ability of spherulites to form in the presence of fatty acid esters and to entrap ascorbyl palmitate, retinyl palmitate, and phytosterol esters; and (d) evaluate the effect of processing conditions on spherulite formation and fatty acid ester entrapment. Higher ratios of linear to branched molecules resulted in the formation of more and rounder spherulites with higher heat stability. In addition to the presence of branches, it appears that spherulitic crystallization is also affected by other factors, such as degree of branching, chain length, and chain length distribution. Amylose and Hylon VII starch formed inclusion complexes with fatty acid esters of ascorbic acid, retinol, or phytosterols

Microbial Transformation of Esters of Chlorinated Carboxylic Acids

PubMed Central

Paris, D. F.; Wolfe, N. L.; Steen, W. C.

1984-01-01

Two groups of compounds were selected for microbial transformation studies. In the first group were carboxylic acid esters having a fixed aromatic moiety and an increasing length of the alkyl component. Ethyl esters of chlorine-substituted carboxylic acids were in the second group. Microorganisms from environmental waters and a pure culture of Pseudomonas putida U were used. The bacterial populations were monitored by plate counts, and disappearance of the parent compound was followed by gas-liquid chromatography as a function of time. The products of microbial hydrolysis were the respective carboxylic acids. Octanol-water partition coefficients (Kow) for the compounds were measured. These values spanned three orders of magnitude, whereas microbial transformation rate constants (kb) varied only 50-fold. The microbial rate constants of the carboxylic acid esters with a fixed aromatic moiety increased with an increasing length of alkyl substituents. The regression coefficient for the linear relationships between log kb and log Kow was high for group 1 compounds, indicating that these parameters correlated well. The regression coefficient for the linear relationships for group 2 compounds, however, was low, indicating that these parameters correlated poorly. PMID:16346459

Three new fatty acid esters from the mushroom Boletus pseudocalopus.

PubMed

Kim, Ki Hyun; Choi, Sang Un; Lee, Kang Ro

2012-06-01

A bioassay-guided fractionation and chemical investigation of a MeOH extract of the Korean wild mushroom Boletus pseudocalopus resulted in the identification of three new fatty acid esters, named calopusins A-C (1-3), along with two known fatty acid methyl esters (4-5). These new compounds are structurally unique fatty acid esters with a 2,3-butanediol moiety. Their structures were elucidated through 1D- and 2D-NMR spectroscopic data and GC-MS analysis as well as a modified Mosher's method. The new compounds 1-3 showed significant inhibitory activity against the proliferation of the tested cancer cell lines with IC(50) values in the range 2.77-12.51 μM.

Methods of refining and producing dibasic esters and acids from natural oil feedstocks

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

Snead, Thomas E; Cohen, Steven A; Gildon, Demond L

2015-04-07

Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

Methods of refining and producing dibasic esters and acids from natural oil feedstocks

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

Snead, Thomas E.; Cohen, Steven A.; Gildon, Demond L.

2016-03-15

Methods are provided for refining natural oil feedstocks and producing dibasic esters and/or dibasic acids. The methods comprise reacting a terminal olefin with an internal olefin in the presence of a metathesis catalyst to form a dibasic ester and/or dibasic acid. In certain embodiments, the olefin esters are formed by reacting the feedstock in the presence of a metathesis catalyst under conditions sufficient to form a metathesized product comprising olefins and esters, separating the olefins from the esters in the metathesized product, and transesterifying the esters in the presence of an alcohol to form a transesterified product having olefin esters.

Exposure to methyl tert-butyl ether and benzene among service station attendants and operators.

PubMed Central

Hartle, R

1993-01-01

Concerns for atmospheric pollution from auto exhaust have led to the blending of "oxygenates" with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: a) service stations that do not use MTBE or use it only as an octane enhancer, b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). At the two sampled service stations that use only minimal amounts of MTBE (less than 1%), only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the analytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8020445

Exposure to methyl tert-butyl ether and benzene among service station attendants and operators.

PubMed

Hartle, R

1993-12-01

Concerns for atmospheric pollution from auto exhaust have led to the blending of "oxygenates" with motor fuels. The most common oxygenate, methyl tert-butyl ether (MTBE) is currently required within several metropolitan areas (Denver and Phoenix) in the range of 12% of the motor fuel. Amendments to the Clean Air Act may expand this requirement to as many as 44 other areas of the United States in the near future. In consideration of the magnitude of potential uncontrolled exposures from its extensive use and a related concern involving the potential influence of MTBE blending on exposures to other constituents of gasoline (particularly benzene), an evaluation of exposures among service station attendants and operators was undertaken at the request, and in cooperation with, the American Petroleum Institute during the latter part of 1990. For application of the survey results to a broad audience, three categories or types of service stations were identified with regard to MTBE use and exposure potential: a) service stations that do not use MTBE or use it only as an octane enhancer, b) service stations with seasonal requirements to use 12-15% MTBE (the Denver, Colorado, and Phoenix, Arizona, metropolitan areas), and c) service stations equipped with stage II (active) vapor recovery systems (several coastal areas, most notably Southern California). At the two sampled service stations that use only minimal amounts of MTBE (less than 1%), only 1 of 32 personal breathing zone (PBZ) samples from attendants was above the analytical limit of detection, reported at 0.16 ppm. The geometric mean concentration of benzene among this same population (n = 32) was 0.04 ppm.(ABSTRACT TRUNCATED AT 250 WORDS)

40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acid polyamine condensate... New Uses for Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric acid... substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and P-90-1985...

40 CFR 721.6200 - Fatty acid polyamine condensate, phosphoric acid ester salts.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty acid polyamine condensate... New Uses for Specific Chemical Substances § 721.6200 Fatty acid polyamine condensate, phosphoric acid... substances identified as fatty acid polyamine condensate, phosphate ester salts (PMNs P-90-1984 and P-90-1985...

Convenient synthesis of 6-nor-9,10-dihydrolysergic acid methyl ester.

PubMed

Crider, A M; Grubb, R; Bachmann, K A; Rawat, A K

1981-12-01

6-Nor-9,10-dihydrolysergic acid methyl ester (IV) was prepared by demethylation of 9,10-dihydrolysergic acid methyl ester (II) with 2,2,2-trichloroethyl chloroformate, followed by reduction of the intermediate carbamate (III) with zinc in acetic acid. The 6-ethyl-V and 6-n-propyl-VI derivatives were prepared by alkylation of IV with the appropriate halide. All of the ergoline derivatives were evaluated for stereotyped behavior in rats, with 6-nor-6-ethyl-9,10-dihydrolysergic acid methyl ester (V) being active but much less potent than apomorphine. Compound VI was evaluated for its effect on blood pressure; at a dose of 30 mg/kg ip, it significantly lowered, diastolic pressure in normotensive rats.

Novel fluoro copolymers for 157-nm photoresists: a progress report

NASA Astrophysics Data System (ADS)

Hohle, Christoph; Hien, Stefan; Eschbaumer, Christian; Rottstegge, Joerg; Sebald, Michael

2002-07-01

Several fluoro-substituted polymers consisting of acid cleavable methacryoic or cinnamic acid tert.-butyl ester compounds copolymerized with maleic acid anhydride derivatives were synthesized by radical copolymerization. Vacuum ultraviolet transmission measurements of the samples reveal absorbances down to 5micrometers -1 despite of the strongly absorbing anhydride moiety which serves as silylation anchor for the application of the Chemical Amplification of Resist Lines (CARL) process, one of the promising approaches for sub-90nm pattern fabrication. Some of the samples exhibit resolutions down to 110nm dense at 157nm exposure using an alternating phase shift mask. The feasibility of the CARL principle including the silylation reaction after development has been demonstrated with selected fluorinated polymer samples.

Amino acid analyses of Apollo 14 samples.

NASA Technical Reports Server (NTRS)

Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Aue, W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

1972-01-01

Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

Simultaneous determination of seven phthalic acid esters in beverages using ultrasound and vortex-assisted dispersive liquid-liquid microextraction followed by high-performance liquid chromatography.

PubMed

Yılmaz, Pelin Köseoğlu; Ertaş, Abdulselam; Kolak, Ufuk

2014-08-01

A sensitive, rapid, and simple high-performance liquid chromatography with UV detection method was developed for the simultaneous determination of seven phthalic acid esters (dimethyl phthalate, dipropyl phthalate, di-n-butyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate, di-(2-ethylhexyl) phthalate, and di-n-octyl phthalate) in several kinds of beverage samples. Ultrasound and vortex-assisted dispersive liquid-liquid microextraction method was used. The separation was performed using an Intersil ODS-3 column (C18 , 250 × 4.6 mm, 5.0 μm) and a gradient elution with a mobile phase consisting of MeOH/ACN (50:50) and 0.2 M KH2 PO4 buffer. Analytes were detected by a UV detector at 230 nm. The developed method was validated in terms of linearity, limit of detection, limit of quantification, repeatability, accuracy, and recovery. Calibration equations and correlation coefficients (> 0.99) were calculated by least squares method with weighting factor. The limit of detection and quantification were in the range of 0.019-0.208 and 0.072-0.483 μg/L. The repeatability and intermediate precision were determined in terms of relative standard deviation to be within 0.03-3.93 and 0.02-4.74%, respectively. The accuracy was found to be in the range of -14.55 to 15.57% in terms of relative error. Seventeen different beverage samples in plastic bottles were successfully analyzed, and ten of them were found to be contaminated by different phthalic acid esters. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Study of the Curing and Flammability Properties of Bisphenol A Epoxy Diacrylate Resin Utilizing a Novel Flame Retardant Monomer, bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl Phosphate

PubMed Central

Rwei, Syang-Peng; Chen, Yu-Ming; Chiang, Whe-Yi; Ting, Yi-Tien

2017-01-01

A UV-curable, flame-retardant monomer, DAPP (bis[di-acryloyloxyethyl]-p-tert-butyl-phenyl-phosphate), was synthesized based on BPDCP (4-tert-butylphenyl-dichloro phosphate) and HEA (2-hydroxy ethyl acrylate). DAPP was blended with regular bisphenol A epoxy acrylate (BAEA) in various ratios to yield various phosphorus contents. The TGA-IR (thermogravimetric analyzer interface with an infrared spectrometer) results demonstrate that compounding 30 mol % DAPP with BAEA significantly reduced the amount of released CO gas. In contrast, the peak intensity of CO2 is independent of phosphorus content. The limiting oxygen index (LOI), reaching the saturated value of 26, and the heat release rate (HRR) measured using a cone-calorimeter, 156.43 KW/m2, confirm the saturation point when 30 mol % DAPP was compounded into BAEA. A study of the kinetics of pyrolysis reveals that Ea decreases as the phosphorus content increases. Both the TGA-IR and pyrolysis results reveal that the phosphorus compound DAPP is easily decomposed during the initial stage of burning to form an insulating layer, which inhibits further burning of the resin and the consequent release of other flammable gases. PMID:28772562

Impact of tert-butyl alcohol on crystallization kinetics of gemcitabine hydrochloride in frozen aqueous solutions.

PubMed

Munjal, Bhushan; Bansal, Arvind K

2015-01-01

The effect of tert-butyl alcohol (TBA) on isothermal crystallization kinetics of gemcitabine hydrochloride (GHCl) in frozen aqueous solutions was assessed by cold-stage microscopy. Addition of TBA (0%-5%, w/w) increased the value of Johnson-Mehl-Avrami rate constant (1.3-33.3 h⁻¹) and reduced the Avrami exponent (2.5-1.0). Thermodynamic parameters [enthalpy (ΔH(‡)), entropy (ΔS(‡)), and free energy (ΔG(‡)) of activation], calculated using Arrhenius and Eyring-Polanyi equations, established that TBA (2%, w/w) accelerated GHCl crystallization by reducing its ΔH(‡) (53.9 cf. 96.5 kJ/mol⁻¹) and ΔG(‡) (68.5 cf. 74.9 kJ/mol⁻¹). Further, to explore insights into the effect of TBA on nucleation and crystal growth of GHCl, crystallization kinetics data were deconvolved using Finke-Watzky model. This revealed that addition of TBA decreased ΔH(‡) of nucleation and increased ΔS(‡) of crystal growth, thereby reducing ΔG(‡) of nucleation and crystal growth by 11.7% and 4.2%, respectively. Finkey-Watzky model also predicted a reduction in the crystal size upon TBA addition, which was confirmed by comparing particle size of GHCl lyophilized in the presence and absence of TBA. In conclusion, TBA reduces ΔG(‡) of nucleation and crystal growth in a differential manner, thereby enhancing the crystallization kinetics of GHCl and affecting its morphological features. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.

Isolation, Solubility, and Characterization of D-Mannitol Esters of 4-Methoxybenzeneboronic Acid.

PubMed

Lopalco, Antonio; Marinaro, William A; Day, Victor W; Stella, Valentino J

2017-02-01

The purpose of this study was to determine the aqueous solubility of a model phenyl boronic acid, 4-methoxybenzeneboronic acid, as a function of pH both in the absence and in the presence of varying D-mannitol concentration. Solid isolated D-mannitol esters were characterized by differential scanning calorimetry, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray studies, and the boronic acid-to-D-mannitol ratio was quantified by HPLC. Hydrolysis of the monoester was studied using UV spectral differences between the monoester and the parent boronic acid. Two D-mannitol esters of 4-methoxybenzeneboronic acid were isolated. The triboronate ester was very insoluble whereas a symmetrical monoboronate monohydrate was also less soluble than the parent. Both esters were crystalline. The monoboronate monohydrate was, however, more soluble than the parent at alkaline pH values due to its lower pKa value (6.53) compared to the parent acid (9.41). Hydrolysis of the monoboronate was extremely fast when even small amount of water was added to dry acetonitrile solutions of the ester. The hydrolysis was buffer concentration dependent and apparent pH sensitive with hydrolysis accelerated by acid. Implications affecting the formulation of future boronic acid drugs are discussed. Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Stability of fluctuating and transient aggregates of amphiphilic solutes in aqueous binary mixtures: Studies of dimethylsulfoxide, ethanol, and tert-butyl alcohol

NASA Astrophysics Data System (ADS)

Banerjee, Saikat; Bagchi, Biman

2013-10-01

In aqueous binary mixtures, amphiphilic solutes such as dimethylsulfoxide (DMSO), ethanol, tert-butyl alcohol (TBA), etc., are known to form aggregates (or large clusters) at small to intermediate solute concentrations. These aggregates are transient in nature. Although the system remains homogeneous on macroscopic length and time scales, the microheterogeneous aggregation may profoundly affect the properties of the mixture in several distinct ways, particularly if the survival times of the aggregates are longer than density relaxation times of the binary liquid. Here we propose a theoretical scheme to quantify the lifetime and thus the stability of these microheterogeneous clusters, and apply the scheme to calculate the same for water-ethanol, water-DMSO, and water-TBA mixtures. We show that the lifetime of these clusters can range from less than a picosecond (ps) for ethanol clusters to few tens of ps for DMSO and TBA clusters. This helps explaining the absence of a strong composition dependent anomaly in water-ethanol mixtures but the presence of the same in water-DMSO and water-TBA mixtures.

Separation of chlorogenic acid and concentration of trace caffeic acid from natural products by pH-zone-refining countercurrent chromatography.

PubMed

Lu, Yuanyuan; Dong, Genlai; Gu, Yanxiang; Ito, Yoichiro; Wei, Yun

2013-07-01

Chlorogenic acid and caffeic acid were selected as test samples for separation by the pH-zone-refining countercurrent chromatography (CCC). The separation of these test samples was performed with a two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/water at a volume ratio of 4:1:5 v/v/v where trifluoroacetic acid (TFA; 8 mM) was added to the organic stationary phase as a retainer and NH4 OH (10 mM) to the aqueous mobile phase as an eluter. Chlorogenic acid was successfully separated from Flaveria bidentis (L.) Kuntze (F. bidentis) and Lonicerae Flos by pH-zone-refining CCC, a slightly polar two-phase solvent system composed of methyl-tert-butyl-ether/acetonitrile/n-butanol/water at a volume ratio of 4:1:1:5 v/v/v/v was selected where TFA (3 mM) was added to the organic stationary phase as a retainer and NH4 OH (3 mM) to the aqueous mobile phase as an eluter. A 16.2 mg amount of chlorogenic acid with the purity of 92% from 1.4 g of F. bidentis, and 134 mg of chlorogenic acid at the purity of 99% from 1.3 g of crude extract of Lonicerae Flos have been obtained. These results suggest that pH-zone-refining CCC is suitable for the isolation of the chlorogenic acid from the crude extracts of F. bidentis and Lonicerae Flos. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

High Performance Fatty Acid-Based Vinyl Ester Resin for Liquid Molding

DTIC Science & Technology

2007-07-01

High Performance Fatty Acid -Based Vinyl Ester Resin for Liquid Molding by Xing Geng, John J. La Scala, James M. Sands, and Giuseppe R...it to the originator. Army Research Laboratory Aberdeen Proving Ground, MD 21005-5069 ARL-RP-184 July 2007 High Performance Fatty Acid ...CONTRACT NUMBER 5b. GRANT NUMBER 4. TITLE AND SUBTITLE High Performance Fatty Acid -Based Vinyl Ester Resin for Liquid Molding 5c. PROGRAM

FT-IR, FT-Raman spectra, density functional computations of the vibrational spectra and molecular conformational analysis of 2,5-di-tert-butyl-hydroquinone

NASA Astrophysics Data System (ADS)

Subramanian, N.; Sundaraganesan, N.; Dereli, Ö.; Türkkan, E.

2011-12-01

The purpose of finding conformer among six different possible conformers of 2,5-di-tert-butyl-hydroquinone (DTBHQ), its equilibrium geometry and harmonic wavenumbers were calculated by the B3LYP/6-31G(d,p) method. The infrared and Raman spectra of DTBHQ were recorded in the region 400-4000 cm -1 and 50-3500 cm -1, respectively. In addition, the IR spectra in CCl 4 at various concentrations of DTBHQ are also recorded. The computed vibrational wavenumbers were compared with the IR and Raman experimental data. Computational calculations at B3LYP level with two different basis sets 6-31G(d,p) and 6-311++G(d,p) are also employed in the study of the possible conformer of DTBHQ. The complete assignments were performed on the basis of the potential energy distribution (PED) of the vibrational modes, calculated using VEDA 4 program. The general agreement between the observed and calculated frequencies was established.

Theoretical and Kinetic Tools for Selecting Effective Antioxidants: Application to the Protection of Omega-3 Oils with Natural and Synthetic Phenols

PubMed Central

Guitard, Romain; Nardello-Rataj, Véronique; Aubry, Jean-Marie

2016-01-01

Radical-scavenging antioxidants play crucial roles in the protection of unsaturated oils against autoxidation and, especially, edible oils rich in omega-3 because of their high sensitivity to oxygen. Two complementary tools are employed to select, among a large set of natural and synthetic phenols, the most promising antioxidants. On the one hand, density functional theory (DFT) calculations provide bond dissociation enthalpies (BDEs) of 70 natural (i.e., tocopherols, hydroxybenzoic and cinnamic acids, flavonoids, stilbenes, lignans, and coumarins) and synthetic (i.e., 2,6-di-tert-butyl-4-methylphenol (BHT), 3-tert-butyl-4-hydroxyanisol (BHA), and tert-butylhydroquinone (TBHQ)) phenols. These BDEs are discussed on the basis of structure–activity relationships with regard to their potential antioxidant activities. On the other hand, the kinetic rate constants and number of hydrogen atoms released per phenol molecule are measured by monitoring the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (DPPH•) radical. The comparison of the results obtained with these two complementary methods allows highlighting the most promising antioxidants. Finally, the antioxidant effectiveness of the best candidates is assessed by following the absorption of oxygen by methyl esters of linseed oil containing 0.5 mmol L−1 of antioxidant and warmed at 90 °C under oxygen atmosphere. Under these conditions, some natural phenols namely epigallocatechin gallate, myricetin, rosmarinic and carnosic acids were found to be more effective antioxidants than α-tocopherol. PMID:27483242

Theoretical and Kinetic Tools for Selecting Effective Antioxidants: Application to the Protection of Omega-3 Oils with Natural and Synthetic Phenols.

PubMed

Guitard, Romain; Nardello-Rataj, Véronique; Aubry, Jean-Marie

2016-07-29

Radical-scavenging antioxidants play crucial roles in the protection of unsaturated oils against autoxidation and, especially, edible oils rich in omega-3 because of their high sensitivity to oxygen. Two complementary tools are employed to select, among a large set of natural and synthetic phenols, the most promising antioxidants. On the one hand, density functional theory (DFT) calculations provide bond dissociation enthalpies (BDEs) of 70 natural (i.e., tocopherols, hydroxybenzoic and cinnamic acids, flavonoids, stilbenes, lignans, and coumarins) and synthetic (i.e., 2,6-di-tert-butyl-4-methylphenol (BHT), 3-tert-butyl-4-hydroxyanisol (BHA), and tert-butylhydroquinone (TBHQ)) phenols. These BDEs are discussed on the basis of structure-activity relationships with regard to their potential antioxidant activities. On the other hand, the kinetic rate constants and number of hydrogen atoms released per phenol molecule are measured by monitoring the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (DPPH(•)) radical. The comparison of the results obtained with these two complementary methods allows highlighting the most promising antioxidants. Finally, the antioxidant effectiveness of the best candidates is assessed by following the absorption of oxygen by methyl esters of linseed oil containing 0.5 mmol L(-1) of antioxidant and warmed at 90 °C under oxygen atmosphere. Under these conditions, some natural phenols namely epigallocatechin gallate, myricetin, rosmarinic and carnosic acids were found to be more effective antioxidants than α-tocopherol.

Widespread occurrence of phthalic acid esters in raw oilseeds in China used for edible vegetable oil production.

PubMed

Hu, Ai-Peng; Liu, Yu-Lan; Shi, Long-Kai

2016-09-01

Seven different phthalic acid esters (PAEs) were quantified in 124 samples of 16 types of oilseeds from China using a simplified GC-MS method. Di-2-ethylhexyl phthalate and di-n-butyl phthalate were found in all tested oilseed samples. Each made a high contribution to the summed total PAEs. Total PAE concentrations in 124 oilseeds ranged from 0.14 to 3.05 mg kg(-1), and the mean was 0.99 mg kg(-1). Mandulapalka (Cyperus esculentus) samples were the most severely contaminated among all the tested specimens; maize germ samples were least contaminated. Di-n-octyl phthalate and butylbenzyl phthalate were not detected in 12 and five types of oilseeds, respectively. Only eight samples contained all seven analytes. No difference was observed between woody oil-bearing plant and herbaceous oil-bearing plant in terms of PAEs content.

Formation of Alkenes via Degradation of tert-Alkyl Ethers and Alcohols by Aquincola tertiaricarbonis L108 and Methylibium spp. ▿†

PubMed Central

Schäfer, Franziska; Muzica, Liudmila; Schuster, Judith; Treuter, Naemi; Rosell, Mònica; Harms, Hauke; Müller, Roland H.; Rohwerder, Thore

2011-01-01

Bacterial degradation pathways of fuel oxygenates such as methyl tert-butyl and tert-amyl methyl ether (MTBE and TAME, respectively) have already been studied in some detail. However, many of the involved enzymes are still unknown, and possible side reactions have not yet been considered. In Aquincola tertiaricarbonis L108, Methylibium petroleiphilum PM1, and Methylibium sp. strain R8, we have now detected volatile hydrocarbons as by-products of the degradation of the tert-alkyl ether metabolites tert-butyl and tert-amyl alcohol (TBA and TAA, respectively). The alkene isobutene was formed only during TBA catabolism, while the beta and gamma isomers of isoamylene were produced only during TAA conversion. Both tert-alkyl alcohol degradation and alkene production were strictly oxygen dependent. However, the relative contribution of the dehydration reaction to total alcohol conversion increased with decreasing oxygen concentrations. In resting-cell experiments where the headspace oxygen content was adjusted to less than 2%, more than 50% of the TAA was converted to isoamylene. Isobutene formation from TBA was about 20-fold lower, reaching up to 4% alcohol turnover at low oxygen concentrations. It is likely that the putative tert-alkyl alcohol monooxygenase MdpJ, belonging to the Rieske nonheme mononuclear iron enzymes and found in all three strains tested, or an associated enzymatic step catalyzed the unusual elimination reaction. This was also supported by the detection of mdpJK genes in MTBE-degrading and isobutene-emitting enrichment cultures obtained from two treatment ponds operating at Leuna, Germany. The possible use of alkene formation as an easy-to-measure indicator of aerobic fuel oxygenate biodegradation in contaminated aquifers is discussed. PMID:21742915

Vibrational frequency analysis, FT-IR, DFT and M06-2X studies on tert-Butyl N-(thiophen-2yl)carbamate.

PubMed

Sert, Yusuf; Singer, L M; Findlater, M; Doğan, Hatice; Çırak, Ç

2014-07-15

In this study, the experimental and theoretical vibrational frequencies of a newly synthesized tert-Butyl N-(thiophen-2yl)carbamate have been investigated. The experimental FT-IR (4000-400 cm(-1)) spectrum of the molecule in the solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters (bond lengths and bond angles) have been calculated by using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr) and DFT/M06-2X (the highly parametrized, empirical exchange correlation function) quantum chemical methods with the 6-311++G(d,p) basis set by Gaussian 09W software, for the first time. The vibrational frequencies have been assigned using potential energy distribution (PED) analysis by using VEDA 4 software. The computational optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data, and with related literature results. In addition, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies and the other related molecular energy values have been calculated and are depicted. Copyright © 2014 Elsevier B.V. All rights reserved.

Polypyrrole-Grafted Coconut Shell Biological Carbon as a Potential Adsorbent for Methyl Tert-Butyl Ether Removal: Characterization and Adsorption Capability

PubMed Central

Li, Shanshan; Qian, Keke; Wang, Shan; Liang, Kaiqiang; Yan, Wei

2017-01-01

Methyl tert-butyl ether (MTBE) has been used as a common gasoline additive worldwide since the late twentieth century, and it has become the most frequently detected groundwater pollutant in many countries. This study aimed to synthesize a novel microbial carrier to improve its adsorptive capacity for MTBE and biofilm formation, compared to the traditional granular activated carbon (GAC). A polypyrrole (PPy)-modified GAC composite (PPy/GAC) was synthesized, and characterized by Fourier transform infrared spectroscopy (FT-IR) and Brunauer-Emmett-Teller (BET) surface area analysis. The adsorption behaviors of MTBE were well described by the pseudo-second-order and Langmuir isotherm models. Furthermore, three biofilm reactors were established with PPy/GAC, PPy, and GAC as the carriers, respectively, and the degradation of MTBE under continuous flow was investigated. Compared to the biofilm reactors with PPy or GAC (which both broke after a period of operation), the PPy/GAC biofilm column produced stable effluents under variable treatment conditions with a long-term effluent MTBE concentration <20 μg/L. Pseudomonas aeruginosa and Acinetobacter pittii may be the predominant bacteria responsible for MTBE degradation in these biofilm reactors. PMID:28125030

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

PubMed

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

2018-04-11

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

Development of solvent-free offset ink using vegetable oil esters and high molecular-weight resin.

PubMed

Park, Jung Min; Kim, Young Han; Kim, Sung Bin

2013-01-01

In the development of solvent-free offset ink, the roles of resin molecular weight and used solvent on the ink performance were evaluated by examining the relationship between the various properties of resin and solvent and print quality. To find the best performing resin, the soy-oil fatty acid methyl ester (FAME) was applied to the five modified-phenolic resins having different molecular weights. It is found from the experimental results that the ink made of higher molecular weight and better solubility resin gives better printability and print quality. It is because larger molecular weight resin with better solubility gives higher rate of ink transfer. From the ink application of different esters to high molecular weight resin, the best printing performance was yielded from the soy-oil fatty acid butyl ester (FABE). It is due to its high kinematic viscosity resulting in the smallest change of ink transfer weight upon multiple number of printing, which improves the stability of ink quality.

Lipase-catalyzed synthesis of fatty acid amide (erucamide) using fatty acid and urea.

PubMed

Awasthi, Neeraj Praphulla; Singh, R P

2007-01-01

Ammonolysis of fatty acids to the corresponding fatty acid amides is efficiently catalysed by Candida antartica lipase (Novozym 435). In the present paper lipase-catalysed synthesis of erucamide by ammonolysis of erucic acid and urea in organic solvent medium was studied and optimal conditions for fatty amides synthesis were established. In this process erucic acid gave 88.74 % pure erucamide after 48 hour and 250 rpm at 60 degrees C with 1:4 molar ratio of erucic acid and urea, the organic solvent media is 50 ml tert-butyl alcohol (2-methyl-2-propanol). This process for synthesis is economical as we used urea in place of ammonia or other amidation reactant at atmospheric pressure. The amount of catalyst used is 3 %.

Methyl tert-butyl ether biodegradation by indigenous aquifer microorganisms under natural and artificial oxic conditions

USGS Publications Warehouse

Landmeyer, J.E.; Chapelle, F.H.; Herlong, H.H.; Bradley, P.M.

2001-01-01

Microbial communities indigenous to a shallow groundwater system near Beaufort, SC, degraded milligram per liter concentrations of methyl tert-butyl ether (MTBE) under natural and artificial oxic conditions. Significant MTBE biodegradation was observed where anoxic, MTBE-contaminated groundwater discharged to a concrete-lined ditch. In the anoxic groundwater adjacent to the ditch, concentrations of MTBE were > 1 mg/L. Where groundwater discharge occurs, dissolved oxygen (DO) concentrations beneath the ditch exceeded 1.0 mg/L to a depth of 1.5 m, and MTBE concentrations decreased to <1 ??g/L prior to discharge. MTBE mass flux calculations indicate that 96% of MTBE mass loss occurs in the relatively small oxic zone prior to discharge. Samples of a natural microbial biofilm present in the oxic zone beneath the ditch completely degraded [U-14C]MTBE to [14C]CO2 in laboratory liquid culture studies, with no accumulation of intermediate compounds. Upgradient of the ditch in the anoxic, MTBE and BTEX-contaminated aquifer, addition of a soluble oxygen release compound resulted in oxic conditions and rapid MTBE biodegradation by indigenous microorganisms. In an observation well located closest to the oxygen addition area, DO concentrations increased from 0.4 to 12 mg/L in <60 days and MTBE concentrations decreased from 20 to 3 mg/L. In the same time period at a downgradient observation well, DO increased from <0.2 to 2 mg/L and MTBE concentrations decreased from 30 to <5 mg/L. These results indicate that microorganisms indigenous to the groundwater system at this site can degrade milligram per liter concentrations of MTBE under natural and artificial oxic conditions.

Determination of asparagine, glutamine and pyrrolidonecarboxylic acid in total enzymic hydrolysates of peptides and glycopeptides by gas–liquid chromatography

PubMed Central

Hediger, Hedy; Stevens, Richard L.; Brandenberger, Hans; Schmid, Karl

1973-01-01

A new procedure for the qualitative and quantitative determination of asparagine, glutamine and pyrrolidonecarboxylic acid in total enzymic hydrolysates of peptides and glycopeptides based on g.l.c. has been developed. Under the conditions of esterification and trifluoroacetylation N-trifluoroacetylaspartic acid mono-n-butyl ester was formed from asparagine and N-trifluoroacetylglutamic acid mono-n-butyl ester from both glutamine and pyrrolidonecarboxylic acid. To distinguish between the latter two compounds, the esterification was carried out at room temperature yielding 30% of esterified pyrrolidonecarboxylic acid but less than 1% of esterified glutamine. In extending the g.l.c. of amino acids, the previously unknown positions in the g.l.c. elution pattern of the following amino acids could also be reproducibly determined: carboxymethylcysteine, homoserine, hydroxylysine and ∈-methyl-lysine. Further, certain glycopeptides were investigated and the artifacts due to their carbohydrate moieties were determined. PMID:4733240

TOXICITY OF METHYL-TERT BYTYL ETHER (MTBE) TO PLANTS (AVENA SATIVA, ZEA MAYS, TRITICUM AESTIVUM, AND LACTUCA SATIVA)

EPA Science Inventory

Effects of Methyl tert-butyl ether (MTBE) on the germination of seeds and growth of the plant were studied in some laboratory experiments. Test plants were wild oat (Avena sative), sweet corn (Zea mays), wheat (Triticum aestivum), and lettuce (Lactuca sativa). Seed germination,...

Methyl tert-butyl ether (MTBE) in public and private wells in New Hampshire: Occurrence, factors, and possible implications

USGS Publications Warehouse

Ayotte, J.D.; Argue, D.M.; McGarry, F.J.; Degnan, J.R.; Hayes, L.; Flanagan, S.M.; Helsel, D.R.

2008-01-01

Methyl tert-butyl ether (MTBE) concentrations ???0.2 ??g/L were found in samples of untreated water in 18% of public-supply wells (n = 284) and 9.1% of private domestic wells (n = 264) sampled in 2005 and 2006 in New Hampshire. In counties that used reformulated gasoline (RFG), MTBE occurred at or above 0.2 ??g/L in 30% of public- and 17% of private-supply wells. Additionally, 52% of public-supply wells collocated with fuel storage and 71% of mobile home park wells had MTBE. MTBE occurrence in public-supply wells was predicted by factors such as proximity to sources of fuel, land use, and population density, as well as low pH and distance from mapped lineaments. RFG use, land-use variables, and pH were important predictors of private-well MTBE occurrence. Variables representing sources of MTBE, such as the distance to known fuel sources, were not significant predictors of MTBE occurrence in private-supply wells. It is hypothesized that private wells may become contaminated from the collective effects of sources in high population areas and from undocumented incidental releases from onsite or proximal gasoline use. From 2003 to 2005, MTBE occurrence decreased in 63 public-supply wells and increased in 60 private-supply wells, but neither trend was statistically significant. ?? 2008 American Chemical Society.

Methyl tert-butyl ether occurrence and related factors in public and private wells in southeast New Hampshire.

PubMed

Ayotte, Joseph D; Argue, Denise M; McGarry, Frederick J

2005-01-01

The occurrence of methyl tert-butyl ether (MTBE) in water from public wells in New Hampshire has increased steadily over the past several years. Using a laboratory reporting level of 0.2 microg/L, 40% of samples from public wells and 21% from private wells in southeast New Hampshire have measurable concentrations of MTBE. The rate of occurrence of MTBE varied significantly for public wells by establishmenttype; for example, 63% of public wells serving residential properties have MTBE concentrations above 0.2 microg/L, whereas lower rates were found for schools (21%). MTBE concentrations correlate strongly with urban factors, such as population density. Surprisingly, MTBE was correlated positively with well depth for public supply wells. Well depth is inversely related to yield in New Hampshire bedrock wells, which may mean that there is less opportunity for dilution of MTBE captured by deep wells. Another possibility is that the source(s) of water to low-yield wells may be dominated by leakage from potentially contaminated shallow groundwater through near-surface fractures or along the well casing. These wells may also have relatively large contributing areas (due to low recharge at the bedrock surface) and therefore have a greater chance of intersecting MTBE sources. This finding is significant because deep bedrock wells are often considered to be less vulnerable to contamination than shallow wells, and in southeast New Hampshire, wells are being drilled deeper in search of increased supply.

40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442) is...

40 CFR 721.3680 - Ethylene oxide adduct of fatty acid ester with pentaerythritol.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Ethylene oxide adduct of fatty acid... New Uses for Specific Chemical Substances § 721.3680 Ethylene oxide adduct of fatty acid ester with... identified generically as ethylene oxide adduct of fatty acid ester with pentaerythritol (PMN P-91-442) is...

Polyphenol fatty acid esters as serine protease inhibitors: a quantum-chemical QSAR analysis.

PubMed

Viskupicova, Jana; Danihelova, Martina; Majekova, Magdalena; Liptaj, Tibor; Sturdik, Ernest

2012-12-01

We investigated the ability of polyphenol fatty acid esters to inhibit the activity of serine proteases trypsin, thrombin, elastase and urokinase. Potent protease inhibition in micromolar range was displayed by rutin and rutin derivatives esterified with medium and long chain, mono- and polyunsaturated fatty acids (1e-m), followed by phloridzin and esculin esters with medium and long fatty acid chain length (2a-d, 3a-d), while unmodified compounds showed only little or no effect. QSAR study of the compounds tested provided the most significant parameters for individual inhibition activities, i.e. number of hydrogen bond donors for urokinase, molecular volume for thrombin, and solvation energy for elastase. According to the statistical analysis, the action of elastase inhibitors is opposed to those of urokinase and thrombin. Cluster analysis showed two groups of compounds: original polyphenols together with rutin esters with short fatty acid chain length and rutin esters with long fatty acid chain length.

Metabolic engineering of Saccharomyces cerevisiae for production of fatty acid short- and branched-chain alkyl esters biodiesel.

PubMed

Teo, Wei Suong; Ling, Hua; Yu, Ai-Qun; Chang, Matthew Wook

2015-01-01

Biodiesel is a mixture of fatty acid short-chain alkyl esters of different fatty acid carbon chain lengths. However, while fatty acid methyl or ethyl esters are useful biodiesel produced commercially, fatty acid esters with branched-chain alcohol moieties have superior fuel properties. Crucially, this includes improved cold flow characteristics, as one of the major problems associated with biodiesel use is poor low-temperature flow properties. Hence, microbial production as a renewable, nontoxic and scalable method to produce fatty acid esters with branched-chain alcohol moieties from biomass is critical. We engineered Saccharomyces cerevisiae to produce fatty acid short- and branched-chain alkyl esters, including ethyl, isobutyl, isoamyl and active amyl esters using endogenously synthesized fatty acids and alcohols. Two wax ester synthase genes (ws2 and Maqu_0168 from Marinobacter sp.) were cloned and expressed. Both enzymes were found to catalyze the formation of fatty acid esters, with different alcohol preferences. To boost the ability of S. cerevisiae to produce the aforementioned esters, negative regulators of the INO1 gene in phospholipid metabolism, Rpd3 and Opi1, were deleted to increase flux towards fatty acyl-CoAs. In addition, five isobutanol pathway enzymes (Ilv2, Ilv5, Ilv3, Aro10, and Adh7) targeted into the mitochondria were overexpressed to enhance production of alcohol precursors. By combining these engineering strategies with high-cell-density fermentation, over 230 mg/L fatty acid short- and branched-chain alkyl esters were produced, which is the highest titer reported in yeast to date. In this work, we engineered the metabolism of S. cerevisiae to produce biodiesels in the form of fatty acid short- and branched-chain alkyl esters, including ethyl, isobutyl, isoamyl and active amyl esters. To our knowledge, this is the first report of the production of fatty acid isobutyl and active amyl esters in S. cerevisiae. Our findings will be useful for

Safety and tolerance of ester-C compared with regular ascorbic acid.

PubMed

Gruenwald, Joerg; Graubaum, Hans-Joachim; Busch, Regina; Bentley, Christine

2006-01-01

The goal of this randomized, double-blind crossover clinical trial in 50 healthy volunteers sensitive to acidic foods was to evaluate whether Ester-C calcium ascorbate causes fewer epigastric adverse effects than are produced by regular ascorbic acid (AA). Volunteers were randomly separated into 2 groups of 25. The study comprised an observation period of 9 days (phase 1 medication for 3 consecutive days, washout phase for 3 consecutive days, phase 2 medication for 3 consecutive days). Participants took 1000 mg vitamin C as Ester-C during phase 1 of the study followed by 1000 mg of vitamin C as AA during phase 2, or vice versa. During the course of the study, 3 examinations for the evaluation of epigastric adverse effects were performed (on days 0, 3, and 9). Participants used a diary to record epigastric adverse effects on a daily basis. In total, 28 (56%) of 50 participants reported 88 epigastric adverse effects of mild to moderate intensity. Of these 88 adverse effects, 33 (37.5%) occurred after intake of Ester-C and 55 (62.5%) were noted after intake of AA. The tolerability of Ester-C was rated "very good" by 72% of participants, whereas AA was rated "very good" by only 54%. This difference is statistically significant (P<.05). Investigators concluded that Ester-C compared with AA caused significantly fewer epigastric adverse effects in participants sensitive to acidic foods and that Ester-C is much better tolerated.

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.

Effect of sugar fatty acid esters on rumen fermentation in vitro.

PubMed

Wakita, M; Hoshino, S

1987-11-01

1. The effect of sugar fatty acid esters (SFEs; currently used as food additives for human consumption) on rumen volatile fatty acids (VFA) and gas production was studied with sheep rumen contents in vitro. 2. Some SFEs having monoester contents of more than 70% increased the molar proportion of propionate in conjunction with reduction in the acetate:propionate ratio when the individual SFE was added to rumen contents in a final concentration of 4 g/l. Laurate sugar ester was the most potent propionate enhancer and rumen gas depressor, the effective dose being as low as 1 g/l in a final concentration. Fatty acid esters other than SFEs had little, if any, effect on rumen VFA production and their molar proportions. 3. Approximately 50% of laurate sugar ester was hydrolysed by in vitro incubation with rumen fluid for 2 h. The addition of fatty acids and sucrose was also effective in the alterations of rumen VFA and gas production. However, the effect of SFEs on in vitro rumen fermentation was significantly greater than that of their constituent fatty acids or sucrose, or both. Accordingly, the effect appeared to be ascribed to the complex action of SFE itself and to its constituents, free fatty acids and sucrose. 4. SFEs, at the level of 4 g/l, reduced substantially the froth formation (ingesta volume increase) and seemed to be effective for the prevention of bloat.

Enzyme-synthesized Poly(amine-co-esters) as Non-viral Vectors for Gene Delivery

PubMed Central

Liu, Jie; Jiang, Zhaozhong; Zhou, Jiangbing; Zhang, Shengmin; Saltzman, W. Mark

2010-01-01

A family of biodegradable poly(amine-co-esters) was synthesized in one step via enzymatic copolymerization of diesters with amino-substituted diols. Diesters of length C4–C12 (i.e., from succinate to dodecanedioate) were successfully copolymerized with diethanolamines with either an alkyl (methyl, ethyl, n-butyl, t-butyl) or an aryl (phenyl) substituent on the nitrogen. Upon protonation at slightly acidic conditions, these poly(amine-co-esters) readily turned to cationic polyelectrolytes, which were capable of condensing with polyanionic DNA to form nanometer-sized polyplexes. In vitro screening with pLucDNA revealed that two of the copolymers, poly(N-methyldiethyleneamine sebacate) (PMSC) and poly(N-ethyldiethyleneamine sebacate) (PESC), possessed comparable or higher transfection efficiencies compared to Lipofectamine 2000. PMSC/pLucDNA and PESC/pLucDNA nanoparticles had desirable particle sizes (40–70 nm) for cellular uptake and were capable of functioning as proton sponges to facilitate endosomal escape after cellular uptake. These polyplex nanoparticles exhibited extremely low cytotoxicity. Furthermore, in vivo gene transfection experiments revealed that PMSC is a substantially more effective gene carrier than PEI in delivering pLucDNAto cells in tumors in mice. All these properties suggest that poly(amine-co-esters) are promising non-viral vectors for safe and efficient DNA delivery in gene therapy. PMID:21171165

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Methyl and ethyl esters of fatty acids produced... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in food, subject to the...

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Methyl and ethyl esters of fatty acids produced... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in food, subject to the...

Novel surface-active oligofructose fatty acid mono-esters by enzymatic esterification.

PubMed

van Kempen, Silvia E H J; Boeriu, Carmen G; Schols, Henk A; de Waard, Pieter; van der Linden, Erik; Sagis, Leonard M C

2013-06-01

This article describes the synthesis of a series of oligofructose monoesters with fatty acids of different chain length (C8, C12, C16 and C18) to obtain food-grade surfactants with a range of amphiphilicity. Reactions were performed in a mixture of DMSO/Bu(t)OH (10/90 v/v) at 60°C and catalysed by immobilised Candida antarctica lipase B. MALDI-TOF-MS analysis showed that the crude reaction products were mixtures of unmodified oligofructose and mostly mono-esters. The conversion into mono-esters increased with the length of the fatty acid chain, reflecting the specificity of the lipase towards more lipophilic substrates. Reverse phase solid phase extraction was used to fractionate the products, which lead to sufficient purity (>93%) of the fatty acid esters for functionality testing. It was shown that derivatives of longer (C16 and C18) fatty acids were more efficient in lowering surface tension and gave a much higher dilatational modulus than derivatives of the shorter (C8 and C12) fatty acids. Copyright © 2012 Elsevier Ltd. All rights reserved.

Inert Reassessment Document for PEG Fatty Acid Esters

EPA Pesticide Factsheets

The tolerance reassessment decision document and action memorandum for the PEG fatty acid ester date September 28, 2005, included two tolerance exemptions (under 40 CFR 180.910 and $) CFR 180.930, respectively)

Two related lithium calixarene complexes, [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN and {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, determined using synchrotron radiation.

PubMed

Lee, Darren S; Elsegood, Mark R J; Redshaw, Carl; Zhan, Shuzhong

2009-08-01

The crystal structures of acetonitrile solvates of two related lithium calixarene complexes have been determined by low-temperature single-crystal X-ray diffraction using synchrotron radiation. Bis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25-methoxy-27-oxidocalix[4]arene)dilithium(I) acetonitrile tetrasolvate, [Li2(C45H57O4)2].4C2H3N or [p-tert-butylcalix[4]arene(OMe)(OH)2(OLi)](2).4MeCN, (I), crystallizes with the complex across a centre of symmetry and with four molecules of unbound acetonitrile of crystallization per complex. Tetraacetonitrilebis(mu-5,11,17,23-tetra-tert-butyl-26,28-dihydroxy-25,27-dioxidocalix[4]arene)tetralithium(I) acetonitrile octasolvate, [Li4(C44H54O4)2(C2H3N)4].8C2H3N or {p-tert-butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}(2).8MeCN, (II), also crystallizes with the complex lying across a centre of symmetry and contains eight molecules of unbound acetonitrile per complex plus four more directly bound to two of the lithium ions, two on each ion. The cores of both complexes are partially supported by O-H...O hydrogen bonds. The methoxy methyl groups in (I) prevent the binding of any more than two Li+ ions, while the corresponding two O-atom sites in (II) bind an extra Li(+) ion each, making four in total. The calixarene cone adopts an undistorted cone conformation in (I), but an elliptical one in (II).

New bis(alkythio) fatty acid methyl esters

USDA-ARS?s Scientific Manuscript database

The addition reaction of dimethyl disulfide (DMDS) to mono-unsaturated fatty acid methyl esters is well-known for analytical purposes to determine the position of double bonds by mass spectrometry. In this work, the classical iodine-catalyzed reaction is expanded to other dialkyl disulfides (RSSR), ...

Pb, Sr and Ba calix[6]arene hexacarboxylic acid octahedral complexation: a dramatic effect of dealkylation

PubMed Central

Adhikari, Birendra Babu; To, Cuong-Alexander; Iwasawa, Tetsuo; Schramm, Michael P.

2015-01-01

Calix[6]arene hexacarboxylic acid binds instantly and with low symmetry to Pb, Sr and Ba. Later a highly symmetric up-down alternating conformation emerges. The solution structures are identical to their p-tert-butylcalix[6]arene hexacarboxylic acid counterparts. With either receptor an octahedral cage is formed around the metal. The transformation from low to high symmetry however proceeds at significantly faster rates for the de-t-butylated host. PMID:26752941

Biodegradation tests of mercaptocarboxylic acids, their esters, related divalent sulfur compounds and mercaptans.

PubMed

Rücker, Christoph; Mahmoud, Waleed M M; Schwartz, Dirk; Kümmerer, Klaus

2018-04-17

Mercaptocarboxylic acids and their esters, a class of difunctional compounds bearing both a mercapto and a carboxylic acid or ester functional group, are industrial chemicals of potential environmental concern. Biodegradation of such compounds was systematically investigated here, both by literature search and by experiments (Closed Bottle Test OECD 301D and Manometric Respirometry Test OECD 301F). These compounds were found either readily biodegradable or at least biodegradable to a significant extent. Some related compounds of divalent sulfur were tested for comparison (mercaptans, sulfides, disulfides). For the two relevant monofunctional compound classes, carboxylic acids/esters and mercaptans, literature data were compiled, and by comparison with structurally similar compounds without these functional groups, the influence of COOH/COOR' and SH groups on biodegradability was evaluated. Thereby, an existing rule of thumb for biodegradation of carboxylic acids/esters was supported by experimental data, and a rule of thumb could be formulated for mercaptans. Concurrent to biodegradation, abiotic processes were observed in the experiments, rapid oxidative formation of disulfides (dimerisation of monomercaptans and cyclisation of dimercaptans) and hydrolysis of esters. Some problems that compromise the reproducibility of biodegradation test results were discussed.

The optical nature of methylsuccinic acid in human urine

NASA Technical Reports Server (NTRS)

Zeitman, B.; Lawless, J. G.

1975-01-01

Methylsuccinic acid was isolated from human urine, derivatized as the di-S-(+)-2-butyl ester, and analyzed using a gas chromatographic system capable of separating the enantiomers of the derivative. The R-(+)-isomer was found to be present. Methylsuccinic acid is potentially important as a criterion for abiogenicity, having been obtained as a racemic mixture from sources known to be abiotic.

Separation and determination of methyl tert-butyl ether and its degradation products by a laboratory-constructed micro-cryogenic chromatographic oven.

PubMed

Liu, Jiemin; Jiang, Guibin; Zhou, Qunfang; Liu, Jingfu; Wen, Meijuan

2003-10-01

A laboratory-made micro-cryogenic chromatographic oven was mainly improved in size, which was controlled at 6 x 6 x 2.5 cm. A thermoelectric system was used to cool the capillary column instead of the traditional liquid cryogen. A cold block connected to the cryogenic module was directly solidified at room temperature with thermally conductive adhesive so that the uniformity of transferring heat was greatly improved, and the size of the system was reduced. Moreover, this system was inexpensive and convenient for both operation and control. The newly developed device coupled with headspace solid-phase microextraction (SPME) was successfully applied to the determination of methyl tert-butyl ether (MTBE) and its degradation products. During the analysis procedure, a 65 microm polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber was used to extract MTBE and its degradation products. The extraction was controlled at 50 degrees C for 30 min and the NaCl content in the sample was maintained at 35%. The limits of detection (LODs) ranged from 0.006 microg mL(-1) (for MTBE) to 0.206 microg mL(-1) (for methyl acetate) and the relative standard deviations (RSD%) were below 4%. The spiked recoveries for the developed method were evaluated using various water samples as a matrix.

Polyelectrolyte brushes grafted from cellulose nanocrystals using Cu-mediated surface-initiated controlled radical polymerization.

PubMed

Majoinen, Johanna; Walther, Andreas; McKee, Jason R; Kontturi, Eero; Aseyev, Vladimir; Malho, Jani Markus; Ruokolainen, Janne; Ikkala, Olli

2011-08-08

Herein we report the synthesis of cellulose nanocrystals (CNCs) grafted with poly(acrylic acid) (PAA) chains of different lengths using Cu-mediated surface initiated-controlled radical polymerization (SI-CRP). First, poly(tert-butylacrylate) (PtBA) brushes were synthesized; then, subsequent acid hydrolysis was used to furnish PAA brushes tethered onto the CNC surfaces. The CNCs were chemically modified to create initiator moieties on the CNC surfaces using chemical vapor deposition (CVD) and continued in solvent phase in DMF. A density of initiator groups of 4.6 bromine ester groups/nm(2) on the CNC surface was reached, suggesting a dense functionalization and a promising starting point for the controlled/living radical polymerization. The SI-CRP of tert-butylacrylate proceeded in a well-controlled manner with the aid of added sacrificial initiator, yielding polymer brushes with polydispersity values typically well below 1.12. We calculated the polymer brush grafting density to almost 0.3 chains/nm(2), corresponding to high grafting densities and dense polymer brush formation on the nanocrystals. Successful rapid acid hydrolysis to remove the tert-butyl groups yielded pH-responsive PAA-polyelectrolyte brushes bound to the CNC surface. Individually dispersed rod-like nanoparticles with brushes of PtBA or PAA were clearly visualized by AFM and TEM imaging.

Organophosphazenes. 15. Reactions of Hexafluorocyclotriphosphazene with Tert- and n-Butyl Lithium Reagents

DTIC Science & Technology

1981-12-04

H ECU’ITY CLASSIFICATION OF THIS PAGE (When frl,* IFnfered) REPORT DOCUMENTATION PAGE - RE INSTRUCTIONSBEFORE COMPLETING FORM 1. REPORT NUMBER 2...GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER 10 _ _ _ _V11 * 4. TITLE (and Subtitle) S. TYPE OF REPORT I PERIOD COVERED Organoohosphazenes. 15...Reactions of Hexafluro- Technical Report cvclotriphosDhazene with Tert- and n-Butvl Lithium Reagents . PERFORMING ORG. REPORT NUMSER 7. AUTHOR•,) S

Rotational Spectroscopy and Quantum Chemical Calculations of a Fruit Ester: the Microwave Spectrum of n-BUTYL Acetate

NASA Astrophysics Data System (ADS)

Attig, T.; Sutikdja, L. W.; Kannengiesser, R.; Stahl, W.; Kleiner, I.

2013-06-01

In the course of our studies on a number of aliphatic ester molecules and natural substances, the rotational spectrum of n-butyl acetate (CH_{3}-COO-C_4H_9) has been recorded for the first time in the 10-13.5 GHz frequency range, using the MB-FTMW spectrometer in Aachen, with an instrumental uncertainty of a few kHz for unblended lines. Three conformers were observed. The main conformer with C_{1} symmetry has a strong spectrum. The other two conformers have C_{s} and C_{1} symmetries. Their intensities are considerably weaker. The quantum chemical calculations of specific conformers were carried out at the MP2/6-311++G(d,p) level, and for the main conformer different levels of theory were calculated. To analyze the internal rotation of the acetyl methyl groups the codes XIAM (based on the Combined Axis Method) and BELGI (based on the Rho-Axis-Method) were used to model the large amplitude motion. The molecular structures of the three conformers were determined and the values of the experimental rotational constants were compared with those obtained by ab initio methods. For all conformers torsional barriers of approximately 100 cm^{-1} were found. This study is part of a larger project which aims at determining the lowest energy conformers and their structures of organic esters and ketones which are of interest for flavour or perfume synthetic applications. Project partly supported by the PHC PROCOPE 25059YB

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

Code of Federal Regulations, 2014 CFR

2014-04-01

... propylene glycol. 172.850 Section 172.850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... CONSUMPTION Multipurpose Additives § 172.850 Lactylated fatty acid esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be safely used in...

Comparison of stabilization by Vitamin E and 2,6-di-tert-butylphenols during polyethylene radio-thermal-oxidation

NASA Astrophysics Data System (ADS)

Richaud, Emmanuel

2014-10-01

This paper reports a compilation of data for PE+Vitamin E and 2,6-di-tert-butylphenols oxidation in radio-thermal ageing. Data unambiguously show that Vitamin E reacts with Prad and POOrad whereas 2,6-di-tert-butyl phenols only react with POOrad. Kinetic parameters of the stabilization reactions for both kinds of antioxidants were tentatively extracted from phenol depletion curves, and discussed regarding the structure of the stabilizer. They were also used for completing an existing kinetic model used for predicting the stabilization by antioxidants. This one permits to compare the efficiency of stabilizer with dose rate or sample thickness.

Crystal structure of (2,2′-bi­pyridine-κ2 N,N′)bis­(3,5-di-tert-butyl-o-benzo­quinonato-κ2 O,O′)ruthenium(II)

PubMed Central

Ali, Akram; Potaskalov, Vadim A.

2017-01-01

In the title mononuclear complex, [Ru(C14H20O2)2(C10H8N2)], the RuII ion has a distorted octa­hedral coordination environment defined by two N atoms of the chelating 2,2′-bi­pyridine ligand and four O atoms from two 3,5-di-tert-butyl-o-benzo­quinone ligands. In the crystal, the complex mol­ecules are linked by inter­molecular C—H⋯O hydrogen bonds and π–π stacking inter­actions between the 2,2′-bi­pyridine ligands [centroid–centroid distance = 3.538 (3) Å], resulting in a layer structure extending parallel to the ab plane. PMID:28316832

Luminescent silver(I) tert-butylethynide compounds with nicotinic/isonicotinic acid as ligands

NASA Astrophysics Data System (ADS)

Xie, Yi-Ming; Fan, Yue-Yue; Lin, Fu-Lin; Hu, Ting; Liu, Jia; Lu, Can-Zhong

2017-12-01

Solvothermal reaction of tBuC≡CAg, AgBF4 and nicotinic/isonicotinic acid in acetonitrile afforded two new silver(I) tert-butylethynide double salts, namely [(tBuC≡CAg)(AgL1)3] (HL1 = nicotinic acid) (1) and [(tBuC≡CAg)(AgL1)2] (HL2 = isonicotinic acid) (2). These compounds have been characterized by elemental analysis, infrared spectra, single-crystal X-ray analysis, X-ray powder diffraction, thermogravimetric analysis, UV-visible absorption spectra, and luminescent measurement. 1 exhibits a two-dimensional coordination network, and 2 features a three-dimensional coordination architecture. Luminescence measurements indicate that 1 shows a fluorescent emission band centered at 568 nm, and 2 exhibits an intense emission maximum at 550 nm and a shoulder peak at 436 nm.

A COMPARISON OF LIQUID AND GAS-PHASE PHOTOOXIDATION TREATMENT OF METHYL TERTIARY BUTYL ETHER: SYNTHETIC AND FIELD SAMPLES

EPA Science Inventory

The feasibility of photo-oxidation treatment of metyl tert-butyl either (MTBE) in water was investigated using two systems, 1) a slurry falling film photo-reactor, and 2) an integrated air-stripping with gas phase photooxidation system. MTBE-contaminated synthetic water and field...

Biofiltration and inhibitory interactions of gaseous benzene, toluene, xylene, and methyl tert-butyl ether.

PubMed

Shim, Eun-Hwa; Kim, Jaisoo; Cho, Kyung-Suk; Ryu, Hee Wook

2006-05-01

This study evaluated the individual and combined removal capacities of benzene, toluene, and xylene (B, T, and X) in the presence and absence of methyl tert-butyl ether (MTBE) in a polyurethane biofilter inoculated with a BTX-degrading microbial consortium, and further examined their interactive effects in various mixtures. In addition, Polymerase chain reaction-denaturing gradient gel electrophoresis and phylogenetic analysis of 16S rRNA gene sequences were used to compare the microbial community structures found in biofilters exposed to the various gases and gas mixtures. The maximum individual elimination capacities (MECs) of B, T, and X were 200, 238, and 400 g m(-3) h(-1), respectively. There was no significant elimination of MTBE alone. Addition of MTBE decreased the MECs of B,T, and X to 75, 100, and 300 g m(-3) h(-1), respectively, indicating that benzene was most strongly inhibited by MTBE. When the three gases were mixed (B + T + X), the removal capacities of individual B, T, and X were 50, 90, and 200 g m(-3) h(-1), respectively. These capacities decreased to 40, 50, and 100 g m(-3) h(-1) when MTBE was added to the mix. The MEC of the three-gas mixture (B + T + X) was 340 g m(-3) h(-1), and that of the four-gas mixture was 200 g m(-3) h(-1). Although MTBE alone was not degraded by the biofilter, it could be co-metabolically degraded in the presence of toluene, benzene, or xylene with the MECs of 34, 23, and 14 g m(-3) h(-1), respectively. The microbial community structure analysis revealed that two large groups could be distinguished based on the presence or absence of MTBE, and many of the dominant bacteria in the consortia were closely related to bacteria isolated from aromatic hydrocarbon-contaminated sites and/ or oil wastewaters. These findings provide important new insights into biofiltration and may be used to improve the rational design of biofilters for remediation of petroleum gas-contaminated airstreams according to composition types of mixed

Trends in Methyl tert-Butyl Ether Concentrations in Private Wells in Southeast New Hampshire: 2005 to 2015.

PubMed

Flanagan, Sarah M; Levitt, Joseph P; Ayotte, Joseph D

2017-02-07

In southeast New Hampshire, where reformulated gasoline was used from the 1990s to 2007, methyl tert-butyl ether (MtBE) concentrations ≥0.2 μg/L were found in water from 26.7% of 195 domestic wells sampled in 2005. Ten years later in 2015, and eight years after MtBE was banned, 10.3% continue to have MtBE. Most wells (140 of 195) had no MtBE detections (concentrations <0.2 μg/L) in 2005 and 2015. Of the remaining wells, MtBE concentrations increased in 4 wells, decreased in 47 wells, and did not change in 4 wells. On average, MtBE concentrations decreased 65% among 47 wells whereas MtBE concentrations increased 17% among 4 wells between 2005 and 2015. The percent change in detection frequency from 2005 to 2015 (the decontamination rate) was lowest (45.5%) in high-population-density areas and in wells completed in the Berwick Formation geologic units. The decontamination rate was the highest (78.6%) where population densities were low and wells were completed in bedrock composed of granite, metamorphic, and mafic rocks. Wells in the Berwick Formation are characteristically deeper and have lower yields than wells in other rock types and have shallower overburden cover, which may allow for more rapid transport of MtBE from land-surface releases. Low-yielding, deep bedrock wells may require large contributing areas to achieve adequate well yield, and thus have a greater chance of intercepting MtBE, in addition to diluting contaminants at a slower rate and thus requiring more time to decontaminate.

Rapid screening of fatty acid alkyl esters in olive oils by time domain reflectometry.

PubMed

Berardinelli, Annachiara; Ragni, Luigi; Bendini, Alessandra; Valli, Enrico; Conte, Lanfranco; Guarnieri, Adriano; Toschi, Tullia Gallina

2013-11-20

The main aim of the present research is to assess the possibility of quickly screening fatty acid alkyl esters (FAAE) in olive oils using time domain reflectometry (TDR) and partial least-squares (PLS) multivariate statistical analysis. Eighteen virgin olive oil samples with fatty acid alkyl ester contents and fatty acid ethyl ester/methyl ester ratios (FAEE/FAME) ranging from 3 to 100 mg kg(-1) and from 0.3 to 2.6, respectively, were submitted to tests with time domain resolution of 1 ps. The results obtained in test set validation demonstrated that this new and fast analytical approach is able to predict FAME, FAEE, and FAME + FAEE contents with R(2) values of 0.905, 0.923, and 0.927, respectively. Further measurements on mixtures between olive oil and FAAE standards confirmed that the prediction is based on a direct influence of fatty acid alkyl esters on the TDR signal. The suggested technique appeared potentially suitable for monitoring one of the most important quality attribute of the olive oil in the extraction process.

In vitro growth inhibition of mastitis causing bacteria by phenolics and metal chelators

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

Chew, B.P.; Tjoelker, L.W.; Tanaka, T.S.

1985-11-01

Antimicrobial activities of three phenolic compounds and four metal chelators were tested at 0, 250, 500, and 1000 ppm in vitro against four major mastitis-causing bacteria, Streptococcus agalactiae, Staphylococcus aureus, Klebsiella pnuemoniae, and Escherichia coli. Overall, butylated hydroxyanisole and tert-butylhydroquinone showed the greatest antimicrobial activity. These phenolics were bactericidal at 250 to 500 ppm against all four bacteria tested. The butylated hydroxytoluene was bactericidal against the gram-positive bacteria but was ineffective against the coliforms. At 250 ppm, disodium ethylenediaminetetraacetic acid was bactericidal against the gram-positive bacteria but much less effective against the gram-negatives. However, diethylene-triaminepentaacetic acid was more growth inhibitorymore » than ethylenediaminetetraacetic acid against the gram-negative bacteria and especially against Escherichia coli. All other compounds were generally much less effective or ineffective against all four microorganisms. Therefore, butylated hydroxyanisole, butylated hydroxytoluene, tert-butylhydroquinone, ethylenediaminetetraacetic acid, and diethylenetriaminepentaacetic acid may have practical implications in the prevention or treatment of bovine mastitis.« less

Preparation of the very acid-sensitive Fmoc-Lys(Mtt)-OH. Application in the synthesis of side-chain to side-chain cyclic peptides and oligolysine cores suitable for the solid-phase assembly of MAPs and TASPs.

PubMed

Aletras, A; Barlos, K; Gatos, D; Koutsogianni, S; Mamos, P

1995-05-01

N alpha-9-Fluorenylmethoxycarbonyl-N epsilon-4=methyltrityl-lysine, [Fmoc-Lys(Mtt)-OH], was prepared in two steps from lysine, in 42% overall yield. The N epsilon-Mtt function can be quantitatively removed upon treatment with 1% TFA in dichloromethane or with a 1:2:7 mixture of acetic acid/trifluoroethanol/dichloromethane for 30 min and 1 h at room temperature, respectively. Under these conditions, groups of the tert-butyl type and peptide ester bonds to TFA-labile resins, such as the 2-chlorodiphenylmethyl- and the Wang-resin, remained intact. The utility of the new derivative in peptide synthesis has been exemplified with the synthesis of a cyclic cholecystokinin analog. As an example of further application, five types of lysine cores suitable for the solid-phase synthesis of one, two or three epitopes containing antigenic peptides or template-assembled synthetic proteins have been synthesized on Merrifield, Wang and 2-chlorodiphenylmethyl resin.

Stable carbon and hydrogen isotope analysis of methyl tert-butyl ether and tert-amyl methyl ether by purge and trap-gas chromatography-isotope ratio mass spectrometry: method evaluation and application.

PubMed

Kujawinski, Dorothea M; Stephan, Manuel; Jochmann, Maik A; Krajenke, Karen; Haas, Joe; Schmidt, Torsten C

2010-01-01

In order to monitor the behaviour of contaminants in the aqueous environment effective enrichment techniques often have to be employed due to their low concentrations. In this work a robust and sensitive purge and trap-gas chromatography-isotope ratio mass spectrometry method for carbon and hydrogen isotope analysis of fuel oxygenates in water is presented. The method evaluation included the determination of method detection limits, accuracy and reproducibility of deltaD and delta(13)C values. Lowest concentrations at which reliable delta(13)C values could be determined were 5 microg L(-1) and 28 microg L(-1) for TAME and MTBE, respectively. Stable deltaD values for MTBE and TAME could be achieved for concentrations as low as 25 and 50 microg L(-1). Good long-term reproducibility of delta(13)C and deltaD values was obtained for all target compounds. But deltaD values varying more than 5 per thousand were observed using different thermal conversion tubes. Thus, a correction of deltaD values in the analysis of groundwater samples was necessary to guarantee comparability of the results. The applicability of this method was shown by the analysis of groundwater samples from a gasoline contaminated site. By two dimensional isotope analysis two locations within this site were identified at which anaerobic and aerobic degradation of methyl tert-butyl ether occurred.

ESTIMATION OF HYDROLYSIS RATE CONSTANTS OF CARBOXYLIC ACID ESTER AND PHOSPHATE ESTER COMPOUNDS IN AQUEOUS SYSTEMS FROM MOLECULAR STRUCTURE BY SPARC

EPA Science Inventory

SPARC (SPARC Performs Automated Reasoning in Chemistry) chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid ester and phosphate ester compounds in aqueous non- aqueous and systems strictly from molecular structure. The energy diffe...

ESTIMATION OF CARBOXYLIC ACID ESTER HYDROLYSIS RATE CONSTANTS

EPA Science Inventory

SPARC chemical reactivity models were extended to calculate hydrolysis rate constants for carboxylic acid esters from molecular structure. The energy differences between the initial state and the transition state for a molecule of interest are factored into internal and external...

Esterification Reaction of Glycerol and Palm Oil Oleic Acid Using Methyl Ester Sulfonate Acid Catalyst as Drilling Fluid Formulation

NASA Astrophysics Data System (ADS)

Sari, V. I.; Hambali, E.; Suryani, A.; Permadi, P.

2017-02-01

Esterification reaction between glycerol with palm oil oleic acid to produce glycerol ester and one of the utilization of glycerol esters is as ingredients of drilling fluids formula for oil drilling needs. The purpose of this research is to get the best conditions of the esterification process. The esterification reaction does with the reactants is glycerol with purity of 97.6%, palm oil oleic acid with the molar ratio is 1:1, Methyl Ester Sulfonate Acid (MESA) catalyst 0.5%, and stirring speed 400 rpm. The temperature range of 180°C to 240°C and the processing time between 120 to 180 minutes. The results showed that the best conditions of the esterification reaction at the temperature 240°C and time process are 180 minute. The increasing temperature resulted that the acid number decreases and causing the conversion increased. The maximum conversion is 99.24%, density 0.93 g/cm3, flash point 241°C, pour point -3°C, the boiling point of 244 °C, the acid value of 1.90 mg KOH/g sample, kinematic viscosity 31.51 cSt (40°C), surface tension 37.0526 dyne/cm and GCMS identification, glycerol ester at 22,256 retention time (minutes) and wide area 73.75 (%). From the research results obtained glycerol ester with characteristics suitable for drilling fluid formulations.

Gas chromatography-vacuum ultraviolet spectroscopy for analysis of fatty acid methyl esters.

PubMed

Fan, Hui; Smuts, Jonathan; Bai, Ling; Walsh, Phillip; Armstrong, Daniel W; Schug, Kevin A

2016-03-01

A new vacuum ultraviolet (VUV) detector for gas chromatography was recently developed and applied to fatty acid methyl ester (FAME) analysis. VUV detection features full spectral acquisition in a wavelength range of 115-240nm, where virtually all chemical species absorb. VUV absorption spectra of 37 FAMEs, including saturated, monounsaturated, and polyunsaturated types were recorded. Unsaturated FAMEs show significantly different gas phase absorption profiles than saturated ones, and these classes can be easily distinguished with the VUV detector. Another advantage includes differentiating cis/trans-isomeric FAMEs (e.g. oleic acid methyl ester and linoleic acid methyl ester isomers) and the ability to use VUV data analysis software for deconvolution of co-eluting signals. As a universal detector, VUV also provides high specificity, sensitivity, and a fast data acquisition rate, making it a powerful tool for fatty acid screening when combined with gas chromatography. The fatty acid profile of several food oil samples (olive, canola, vegetable, corn, sunflower and peanut oils) were analyzed in this study to demonstrate applicability to real world samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

Synthesis of TMP-ester biolubricant basestock from palm stearin fatty acids

NASA Astrophysics Data System (ADS)

Fadzel, Fatimatuzzahraa Mohd; Salimon, Jumat; Derawi, Darfizzi

2018-04-01

A potential biolubricant; TMP-ester was produced via esterification of fatty acids (FA) from palm stearin (PS) with trimethylolpropane (TMP). The synthesis was conducted at four conditions; temperature, time, molar ratio of FA:TMP and H2SO4 as catalyst (by percent based on the weight of FA and TMP) that are 150 °C, 2 hours, 4:1 and 1% of H2SO4 respectively. The composition of ester produced was determined using gas chromatography (GC-FID). The presence of ester group was confirmed by the means of FTIR by the existence of strong carboxyl band of ester, v(C=O) at 1746cm-1 and 1H and 13C NMR spectroscopy shows the chemical shift, δ of ester, C=O at 2.27-2.31 ppm and 173.45 ppm accordingly. From the esterification reaction, 95% product of TMP-ester was formed. The thermal and oxidative stability of TMP-ester is 200°C.

[Antihistaminic and antiserotonin properties of new complex tropine esters].

PubMed

Mashkovskiĭ, M D; Shvarts, G Ia

1979-01-01

The antihistaminic and antiserotonin properties of 16 new tropine esters, analogues of atropine, tropacin and tropaphen, were studied. All of them were found to lessen the spasmogenic effects of histamine and serotonin. The intensity of the antihistaminic and antiserotonin action of the drugs varied depending upon the structure of the radical at the alpha-carbon atom in the acidic part of the molecule. Both types of the activity are most marked in the desoxymethyl propyl and butyl analogues of atropine. The absence of the oxymethyl group at alpha-carbon in the series of atropine analogues is shown to facilitate the manifestation of the antihistaminic activity.

Tandem Carbocupration/Oxygenation of Terminal Alkynes

PubMed Central

Zhang, Donghui; Ready, Joseph M.

2008-01-01

A direct and general synthesis of α-branched aldehydes and their enol derivatives is described. Carbocupration of terminal alkynes and subsequent oxygenation with lithium tert-butyl peroxide generates a metallo-enolate. Trapping with various electrophiles provides α-branched aldehydes or stereo-defined trisubstituted enol esters or silyl ethers. The tandem carbocupration/oxygenation tolerates alkyl and silyl ethers, esters and tertiary amines. The reaction is effective with organocopper complexes derived from primary, secondary and tertiary Grignard reagents and from n-butyllithium. PMID:16321021

75 FR 70254 - Typographical Error in Summary Notice of Filing in Docket for Polymerized Fatty Acid Esters With...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-17

... Notice of Filing in Docket for Polymerized Fatty Acid Esters With Aminoalcohol Alkoxylates; Correction... (NOF) for Pesticide Petition (PP) 0E7699 for polymerized fatty acid esters with aminoalcohol... Pesticide Petition (PP) 0E7699 for polymerized fatty acid esters with aminoalcohol alkoxylates submitted by...

A 13C NMR study of the structure of four cinnamic acids and their methyl esters

NASA Astrophysics Data System (ADS)

Silva, A. M. S.; Alkorta, I.; Elguero, J.; Silva, V. L. M.

2001-09-01

The 13C NMR spectra, both in DMSO solution and in the solid state of four cinnamic acids (p-methoxy, p-hydroxy, p-methyl, p-chloro) and their corresponding methyl esters have been recorded. The two main results in the solid state are: (i) the only significant difference between acids and esters chemical shifts concerns the Cdbnd O group which, on average, appears at 173 ppm in the acids and 168 ppm in the esters; (ii) the signals of the ortho and meta carbons both in the acids and the esters are splitted. The two 'anomalies' disappear in DMSO solution. These observations can be rationalized using simple GIAO/B3LYP/6-31G∗ calculations.

40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

Code of Federal Regulations, 2010 CFR

2010-07-01

...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products...

40 CFR 721.10136 - 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl...

Code of Federal Regulations, 2011 CFR

2011-07-01

...-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl)melamine (generic). 721.10136 Section 721.10136... 2-Propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products with hexakis(alkoxyalkyl... substance identified generically as 2-propenoic acid, 2-methyl-, 2-hydroxyethyl ester, reaction products...

Effects of Fatty Acid Addition to Oil-in-water Emulsions Stabilized with Sucrose Fatty Acid Ester.

PubMed

Watanabe, Takamasa; Kawai, Takahiro; Nonomura, Yoshimune

2018-03-01

Adding fatty acids to an oil-in-water (O/W) emulsion changes the stability of the emulsion. In this study, we prepared a series of O/W emulsions consisting of oil (triolein/fatty acid mixture), water and a range of surfactants (sucrose fatty acid esters) with varying hydrophilic-lipophilic balance (HLB) in order to determine the effects of alkyl chain length and the degree of unsaturation of the fatty acid molecules on the stability of the emulsions. As a result, sucrose fatty acid esters with HLB = 5-7 were suitable for obtaining O/W emulsions. In addition, the creaming phenomenon was inhibited for 30 days or more when fatty acids having a linear saturated alkyl chain with 14 or more carbon atoms were added. These findings are useful for designing stable O/W emulsions for food and cosmetic products.

Metabolism of hydroxycinnamic acids and esters by Brettanomyces in different red wines

USDA-ARS?s Scientific Manuscript database

Depending on the cultivars and other factors, differing concentrations of hydroxycinnamic acids (caffeic, p-coumaric, and ferulic acids) and their corresponding tartaric acid esters (caftaric, coutaric, and fertaric acid, respectively) are found in red wines. Hydroxycinnamic acids are metabolized by...

Reductive Etherification of Fatty Acids or Esters with Alcohols using Molecular Hydrogen.

PubMed

Erb, Benjamin; Risto, Eugen; Wendling, Timo; Gooßen, Lukas J

2016-06-22

In the presence of a catalyst system consisting of a ruthenium/triphos complex and the Brønsted acid trifluoromethanesulfonimide, mixtures of fatty acids and aliphatic alcohols are converted into the corresponding ethers at 70 bar H2 . The protocol allows the sustainable one-step synthesis of valuable long-chain ether fragrances, lubricants, and surfactants from renewable sources. The reaction protocol is extended to various fatty acids and esters both in pure form and as mixtures, for example, tall oil acids or rapeseed methyl ester (RME). Even the mixed triglyceride rapeseed oil was converted in one step. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of an acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters

DOEpatents

Moens, Luc

1999-01-01

A process of preparing an acid addition salt of delta-aminolevulinic acid comprising: dissolving a lower alkyl 5-bromolevulinate and an alkali metal diformylamide in an organic solvent selected from the group consisting of acetonitrile, methanol, tetrahydrofuran, 2-methyltetrahydrofuran and methylformate or mixtures thereof to form a suspension of an alkyl 5-(N,N-diformylamino) levulinate ester; and hydrolyzing said alkyl 5-(N,N-diformylamino) levulinate with an inorganic acid to form an acid addition salt of delta-amino levulinic acid.

Synthesis, characterization, and properties of peroxo-based oxygen-rich compounds for potential use as greener high energy density materials

NASA Astrophysics Data System (ADS)

Gamage, Nipuni-Dhanesha Horadugoda

One main aspect of high energy density material (HEDM) design is to obtain greener alternatives for HEDMs that produce toxic byproducts. Primary explosives lead azide, lead styphnate, and mercury fulminate contain heavy metals that cause heavy metal poisoning. Leaching of the widely used tertiary explosive NH4ClO4 into groundwater has resulted in human exposure to ClO4-- ions, which cause disruptions of thyroid related metabolic pathways and even thyroid cancer. Many research efforts to find replacements have gained little success. Thus, there is a need for greener HEDMs. Peroxo-based oxygen-rich compounds are proposed as a potential new class of greener HEDMs due to the evolution of CO2 and/or CO, H2O, and O 2 as the main decomposition products. Currently, triacetone triperoxide (TATP), diacetone diperoxide (DADP), hexamethylene triperoxide diamine (HMTD), and methyl ethyl ketone peroxide (MEKP) are the only well-studied highly energetic peroxides. However, due to their high impact and friction sensitivities, low thermal stabilities, and low detonation velocities they have not found any civil or military HEDM applications. In this dissertation research, we have synthesized and fully characterized four categories of peroxo-based compounds: tert-butyl peroxides, tert-butyl peroxy esters, hydroperoxides, and peroxy acids to perform a systematic study of their sensitivities and the energetic properties for potential use as greener HEDMs. tert-Butyl peroxides were not sensitive to impact, friction, or electrostatic spark. Hence, tert-butyl peroxides can be described as fairly safe peroxo-based compounds to handle. tert-Butyl peroxy esters were all surprisingly energetic (4896--6003 m/s), despite the low oxygen and nitrogen contents. Aromatic tert -butyl peroxy esters were much lower in impact and friction sensitivities with respect to the known peroxo-based explosives. These are among the first low sensitivity peroxo-based compounds that can be categorized as secondary

40 CFR 721.10369 - Carbonic acid, diphenyl ester, polymer with diphenyl P-methylphosphonate and 4,4′-(1...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Carbonic acid, diphenyl ester, polymer... Carbonic acid, diphenyl ester, polymer with diphenyl P-methylphosphonate and 4,4′-(1-methylethylidene) bis... identified as carbonic acid, diphenyl ester, polymer with diphenyl P-methylphosphonate and 4,4′-(1...

Molecular assembly, interfacial rheology and foaming properties of oligofructose fatty acid esters.

PubMed

van Kempen, Silvia E H J; Schols, Henk A; van der Linden, Erik; Sagis, Leonard M C

2014-01-01

Two major types of food-grade surfactants used to stabilize foams are proteins and low molecular weight (LMW) surfactants. Proteins lower the surface tension of interfaces and tend to unfold and stabilize the interface by the formation of a visco-elastic network, which leads to high surface moduli. In contrast, LMW surfactants lower the surface tension more than proteins, but do not form interfaces with a high modulus. Instead, they stabilize the interface through the Gibbs-Marangoni mechanism that relies on rapid diffusion of surfactants, when surface tension gradients develop as a result of deformations of the interface. A molecule than can lower the surface tension considerably, like a LMW surfactant, but also provide the interface with a high modulus, like a protein, would be an excellent foam stabilizer. In this article we will discuss molecules with those properties: oligofructose fatty acid esters, both in pure and mixed systems. First, we will address the synthesis and structural characterization of the esters. Next, we will address self-assembly and rheological properties of air/water interfaces stabilized by the esters. Subsequently, this paper will deal with mixed systems of mono-esters with either di-esters and lauric acid, or proteins. Then, the foaming functionality of the esters is discussed.

Carbon Conversion Efficiency and Limits of Productive Bacterial Degradation of Methyl tert-Butyl Ether and Related Compounds▿

PubMed Central

Müller, Roland H.; Rohwerder, Thore; Harms, Hauke

2007-01-01

The utilization of the fuel oxygenate methyl tert-butyl ether (MTBE) and related compounds by microorganisms was investigated in a mainly theoretical study based on the YATP concept. Experiments were conducted to derive realistic maintenance coefficients and Ks values needed to calculate substrate fluxes available for biomass production. Aerobic substrate conversion and biomass synthesis were calculated for different putative pathways. The results suggest that MTBE is an effective heterotrophic substrate that can sustain growth yields of up to 0.87 g g−1, which contradicts previous calculation results (N. Fortin et al., Environ. Microbiol. 3:407-416, 2001). Sufficient energy equivalents were generated in several of the potential assimilatory routes to incorporate carbon into biomass without the necessity to dissimilate additional substrate, efficient energy transduction provided. However, when a growth-related kinetic model was included, the limits of productive degradation became obvious. Depending on the maintenance coefficient ms and its associated biomass decay term b, growth-associated carbon conversion became strongly dependent on substrate fluxes. Due to slow degradation kinetics, the calculations predicted relatively high threshold concentrations, Smin, below which growth would not further be supported. Smin strongly depended on the maximum growth rate μmax, and b and was directly correlated with the half maximum rate-associated substrate concentration Ks, meaning that any effect impacting this parameter would also change Smin. The primary metabolic step, catalyzing the cleavage of the ether bond in MTBE, is likely to control the substrate flux in various strains. In addition, deficits in oxygen as an external factor and in reduction equivalents as a cellular variable in this reaction should further increase Ks and Smin for MTBE. PMID:17220260

Trends in methyl tert-butyl ether concentrations in private wells in southeast New Hampshire: 2005 to 2015

USGS Publications Warehouse

Flanagan, Sarah; Levitt, Joseph; Ayotte, Joseph

2017-01-01

In southeast New Hampshire, where reformulated gasoline was used from the 1990s to 2007, methyl tert-butyl ether (MtBE) concentrations ≥0.2 μg/L were found in water from 26.7% of 195 domestic wells sampled in 2005. Ten years later in 2015, and eight years after MtBE was banned, 10.3% continue to have MtBE. Most wells (140 of 195) had no MtBE detections (concentrations <0.2 μg/L) in 2005 and 2015. Of the remaining wells, MtBE concentrations increased in 4 wells, decreased in 47 wells, and did not change in 4 wells. On average, MtBE concentrations decreased 65% among 47 wells whereas MtBE concentrations increased 17% among 4 wells between 2005 and 2015. The percent change in detection frequency from 2005 to 2015 (the decontamination rate) was lowest (45.5%) in high-population-density areas and in wells completed in the Berwick Formation geologic units. The decontamination rate was the highest (78.6%) where population densities were low and wells were completed in bedrock composed of granite, metamorphic, and mafic rocks. Wells in the Berwick Formation are characteristically deeper and have lower yields than wells in other rock types and have shallower overburden cover, which may allow for more rapid transport of MtBE from land-surface releases. Low-yielding, deep bedrock wells may require large contributing areas to achieve adequate well yield, and thus have a greater chance of intercepting MtBE, in addition to diluting contaminants at a slower rate and thus requiring more time to decontaminate.

Metabolism of hydroxycinnamic acids and their tartaric acid esters by Brettanomyces and Pediococcus in red wines.

USDA-ARS?s Scientific Manuscript database

Caffeic, p-coumaric, and ferulic acids and their corresponding tartaric acid esters (caftaric, coutaric, and fertaric, respectively) are found in wines in varying concentrations. While Brettanomyces and Pediococcus can utilize the free acids, it is not known whether they can metabolize the correspon...

27 CFR 21.100 - n-Butyl alcohol.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false n-Butyl alcohol. 21.100 Section 21.100 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT....100 n-Butyl alcohol. (a) Acidity (as acetic acid). 0.03 percent by weight maximum. (b) Color...

27 CFR 21.100 - n-Butyl alcohol.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false n-Butyl alcohol. 21.100 Section 21.100 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT....100 n-Butyl alcohol. (a) Acidity (as acetic acid). 0.03 percent by weight maximum. (b) Color...

Synthesis of an acid addition salt of delta-aminolevulinic acid from 5-bromo levulinic acid esters

DOEpatents

Moens, L.

1999-05-25

A process is disclosed for preparing an acid addition salt of delta-aminolevulinic acid comprising. The process involves dissolving a lower alkyl 5-bromolevulinate and an alkali metal diformylamide in an organic solvent selected from the group consisting of acetonitrile, methanol, tetrahydrofuran, 2-methyltetrahydrofuran and methylformate or mixtures to form a suspension of an alkyl 5-(N,N-diformylamino) levulinate ester; and hydrolyzing the alkyl 5-(N,N-diformylamino) levulinate with an inorganic acid to form an acid addition salt of delta-amino levulinic acid.

Disposition of 2,6-di-tert-butyl-4-nitrophenol (DBNP), a submarine atmosphere contaminant, in male Sprague-Dawley rats.

PubMed

Still, Kenneth R; Jung, Anne E; Ritchie, Glenn D; Jederberg, Warren W; Wilfong, Erin R; Briggs, G Bruce; Arfsten, Darryl P

2005-07-01

The phenol 2,6-di-tert-butyl-4-nitrophenol (DBNP) is a contaminant found onboard submarines and is formed by the nitration of an antioxidant present in turbine lubricating oil TEP 2190. DBNP has been found on submarine interior surfaces, on eating utensils and dishes, and on the skin of submariners. DBNP exposure is a potential health concern because it is an uncoupler of mitochondrial oxidative phosphorylation. Adult male rats were dosed once by oral gavage with 15 or 40 mg/kg DBNP mixed with 14C-DBNP in kanola oil and 0.8% v/v DMSO (n = 16/group). The distribution of 14C in major tissues was measured over time for up to 240 h post-dose. Unexpectedly, 6/16 (40%) of the rats gavaged with 40 mg/kg DBNP died within 24 h of dosing. Prostration, no auditory startle response, reduced locomotor activity, and muscular rigidity persisted in survivors for up to 8 days after dosing. For animals dosed with 15 mg/kg DBNP, radioactivity levels were significantly elevated in the following tissues 24h after dosing: fat>liver>kidneys>heart>lungs>brain>striated muscle>spleen. Radioactivity levels were elevated for fat, liver, kidney, heart, and lungs of animals euthanized 144 h post-dosing and in the liver of animals euthanized 240 h post-dosing. These findings suggest that DBNP may accumulate in the body as a result of continuous or repeat exposures of short interval to DBNP.

Bacopa monnieri protects SH-SY5Y cells against tert-Butyl hydroperoxide-induced cell death via the ERK and PI3K pathways

PubMed Central

Petcharat, Kanoktip; Singh, Meharvan; Ingkaninan, Kornkanok; Attarat, Jongrak; Yasothornsrikul, Sukkid

2017-01-01

Objective Oxidative stress plays an important role in the pathological processes of various neurodegenerative diseases. Bacopa monnieri (BM) has a potent antioxidant property. Therefore, the purpose of this study was to evaluate the neuroprotective potential of BM against SH-SY5Y neuroblastoma cell death induced by the pro-oxidant insult, tert-Butyl hydroperoxide (TBHP), and to identify possible mechanisms related to its neuroprotective action. Methods The neuroprotective effect of BM was evaluated by the degree of protection against TBHP-induced cell death in human SH-SY5Y cells that was measured by calcein-AM assay. ERK1/2 and Akt phosphorylation was evaluated by immunoblotting. Results We found that BM exhibited protection against TBHP-mediated cytotoxicity. The neuroprotective effect of BM was abolished in the presence of either ERK1/2 or PI3K inhibitors. In addition, western blotting with anti-phospho-ERK1/2 and anti-phospho-Akt antibodies showed that BM increased both ERK1/2 and Akt phosphorylation. Conclusion These results suggest that BM by activation of ERK/MAPK and PI3K/Akt signaling pathways protects SH-SY5Y cells from TBHP-induced cell death. PMID:29152617

Bacopa monnieri protects SH-SY5Y cells against tert-Butyl hydroperoxide-induced cell death via the ERK and PI3K pathways.

PubMed

Petcharat, Kanoktip; Singh, Meharvan; Ingkaninan, Kornkanok; Attarat, Jongrak; Yasothornsrikul, Sukkid

2015-01-01

Oxidative stress plays an important role in the pathological processes of various neurodegenerative diseases. Bacopa monnieri (BM) has a potent antioxidant property. Therefore, the purpose of this study was to evaluate the neuroprotective potential of BM against SH-SY5Y neuroblastoma cell death induced by the pro-oxidant insult, tert -Butyl hydroperoxide (TBHP), and to identify possible mechanisms related to its neuroprotective action. The neuroprotective effect of BM was evaluated by the degree of protection against TBHP-induced cell death in human SH-SY5Y cells that was measured by calcein-AM assay. ERK1/2 and Akt phosphorylation was evaluated by immunoblotting. We found that BM exhibited protection against TBHP-mediated cytotoxicity. The neuroprotective effect of BM was abolished in the presence of either ERK1/2 or PI3K inhibitors. In addition, western blotting with anti-phospho-ERK1/2 and anti-phospho-Akt antibodies showed that BM increased both ERK1/2 and Akt phosphorylation. These results suggest that BM by activation of ERK/MAPK and PI3K/Akt signaling pathways protects SH-SY5Y cells from TBHP-induced cell death.

Evaluation of salicylic acid fatty ester prodrugs for UV protection.

PubMed

Im, Jong Seob; Balakrishnan, Prabagar; Oh, Dong Hoon; Kim, Jung Sun; Jeon, Eun-Mi; Kim, Dae-Duk; Yong, Chul Soon; Choi, Han-Gon

2011-07-01

The purpose of this study was to investigate the physicochemical properties and in vitro evaluation of fatty ester prodrugs of salicylic acid for ultraviolet (UV) protection. The physicochemical properties such as lipophilicity, chemical stability and enzymatic hydrolysis were investigated with the following fatty ester prodrugs of salicylic acid: octanoyl (C8SA), nonanoyl (C9SA), decanoyl (C10SA), lauroyl (C12SA), myristoyl (C14SA) and palmitoyl oxysalicylate (C16SA). Furthermore, their skin permeation and accumulation were evaluated using a combination of common permeation enhancing techniques such as the use of a lipophilic receptor solution, removal of stratum corneum and delipidization of skin. Their k' values were proportional to the degree of carbon-carbon saturation in the side chain. All these fatty esters were highly stable in 2-propanol, acetonitrile and glycerin, but unstable in methanol and ethanol. They were relatively unstable in liver and skin homogenates. In particular, C16SA was mostly hydrolyzed to its parent compound in hairless mouse liver and skin homogenates, suggesting that it might be converted to salicylic acid after its topical administration. In the skin permeation and accumulation study, C16SA showed the poorest permeation in all skins, suggesting that it could not be permeated in the skin. Furthermore, C14SA and C16SA were less accumulated in delipidized skin compared with normal skin or stripped skin, suggesting that these esters had relatively strong affinities for lipids compared with the other prodrugs in the skin. C16SA showed significantly higher dermal accumulation in all skins compared with its parent salicylic acid. Thus, the palmitoyl oxysalicylate (C16SA) might be a potential candidate for UV protection due to its absence of skin permeation, smaller uptake in the lipid phase and relatively lower skin accumulation.

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.

Optimization of headspace solid-phase microextraction by means of an experimental design for the determination of methyl tert.-butyl ether in water by gas chromatography-flame ionization detection.

PubMed

Dron, Julien; Garcia, Rosa; Millán, Esmeralda

2002-07-19

A procedure for determination of methyl tert.-butyl ether (MTBE) in water by headspace solid-phase microextraction (HS-SPME) has been developed. The analysis was carried out by gas chromatography with flame ionization detection. The extraction procedure, using a 65-microm poly(dimethylsiloxane)-divinylbenzene SPME fiber, was optimized following experimental design. A fractional factorial design for screening and a central composite design for optimizing the significant variables were applied. Extraction temperature and sodium chloride concentration were significant variables, and 20 degrees C and 300 g/l were, respectively chosen for the best extraction response. With these conditions, an extraction time of 5 min was sufficient to extract MTBE. The calibration linear range for MTBE was 5-500 microg/l and the detection limit 0.45 microg/l. The relative standard deviation, for seven replicates of 250 microg/l MTBE in water, was 6.3%.

Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity.

PubMed

Vaisali, C; Belur, Prasanna D; Regupathi, Iyyaswami

2017-10-01

Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents. Copyright © 2017 Elsevier Ltd. All rights reserved.

Antioxidant action of 3-mercapto-5H-1,2,4-triazino[5,6-b]indole-5-acetic acid, an efficient aldose reductase inhibitor, in a 1,1'-diphenyl-2-picrylhydrazyl assay and in the cellular system of isolated erythrocytes exposed to tert-butyl hydroperoxide.

PubMed

Prnova, Marta Soltesova; Ballekova, Jana; Majekova, Magdalena; Stefek, Milan

2015-01-01

The subject of this study was 3-mercapto-5H-1,2,4-triazino[5,6-b]indole-5-acetic acid (compound 1), an efficient aldose reductase inhibitor of high selectivity. The antioxidant action of 1 was investigated in greater detail by employing a 1,1'-diphenyl-2-picrylhydrazyl (DPPH) test and in the system of isolated rat erythrocytes. First, the compound was subjected to the DPPH test. Second, the overall antioxidant action of the compound was studied in the cellular system of isolated rat erythrocytes oxidatively stressed by free radicals derived from the lipophilic tert-butyl hydroperoxide. The uptake kinetics of 1 was studied and osmotic fragility of the erythrocytes was evaluated. The DPPH test revealed significant antiradical activity of 1. One molecule of 1 was found to quench 1.48 ± 0.06 DPPH radicals. In the system of isolated erythrocytes, the compound was readily taken up by the cells followed by their protection against free radical-initiated hemolysis. Osmotic fragility of the erythrocytes was not affected by 1. The results demonstrated the ability of 1 to scavenge DPPH and to protect intact erythrocytes against oxidative damage induced by peroxyl radicals. By affecting both the polyol pathway and oxidative stress, the compound represents an example of a promising agent for multi-target pharmacology of diabetic complications.

Methyl tert-butyl ether (MTBE) detected in abnormally high concentrations in postmortem blood and urine from two persons found dead inside a car containing a gasoline spill.

PubMed

Karinen, Ritva; Vindenes, Vigdis; Morild, Inge; Johnsen, Lene; Le Nygaard, Ilah; Christophersen, Asbjørg S

2013-09-01

Two deep frozen persons, a female and a male, were found dead in a car. There had been an explosive fire inside the car which had extinguished itself. On the floor inside the car were large pools of liquid which smelled of gasoline. The autopsy findings and routine toxicological analyses could not explain the cause of death. Carboxyhemoglobin levels in the blood samples were <10%. Analysis with a headspace gas chromatography revealed methyl tert-butyl ether (MTBE) concentrations of 185 mg/L (female victim) and 115 mg/L (male victim) in peripheral blood. The urine MTBE concentrations were 150 mg/L and 256 mg/L, respectively. MTBE is a synthetic chemical which is added to gasoline as a fuel oxygenate. Gasoline poisoning is likely to be the cause of the death in these two cases, and MTBE can be a suitable marker of gasoline exposure, when other volatile components have vaporized. © 2013 American Academy of Forensic Sciences.

40 CFR 721.10289 - Hexanedioic acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Hexanedioic acid polymer with... polymer with aliphatic polyol dihydrogen phosphate aromatic ester (generic). (a) Chemical substance and... acid polymer with aliphatic polyol dihydrogen phosphate aromatic ester (PMN P-11-333) is subject to...

Removal of the endocrine disrupter butyl benzyl phthalate from the environment

PubMed Central

Karlovsky, Petr

2010-01-01

Butyl benzyl phthalate (BBP), an aryl alkyl ester of 1,2-benzene dicarboxylic acid, is extensively used in vinyl tiles and as a plasticizer in PVC in many commonly used products. BBP, which readily leaches from these products, is one of the most important environmental contaminants, and the increased awareness of its adverse effects on human health has led to a dramatic increase in research aimed at removing BBP from the environment via bioremediation. This review highlights recent progress in the degradation of BBP by pure and mixed bacterial cultures, fungi, and in sludge, sediment, and wastewater. Sonochemical degradation, a unique abiotic remediation technique, and photocatalytic degradation are also discussed. The degradation pathways for BBP are described, and future research directions are considered. PMID:20396882

α,β-Unsaturated monoterpene acid glucose esters: structural diversity, bioactivities and functional roles.

PubMed

Goodger, Jason Q D; Woodrow, Ian E

2011-12-01

The glycosylation of lipophilic small molecules produces many important plant secondary metabolites. The majority of these are O-glycosides with relatively fewer occurring as glucose esters of aromatic or aliphatic acids. In particular, monoterpene acid glucose esters have much lower structural diversity and distribution compared to monoterpene glycosides. Nevertheless, there have been over 20 monoterpene acid glucose esters described from trees in the genus Eucalyptus (Myrtaceae) in recent years, all based on oleuropeic acid, menthiafolic acid or both. Here we review all of the glucose esters containing these monoterpenoids identified in plants to date. Many of the compounds contain phenolic aglycones and all contain at least one α,β-unsaturated carbonyl, affording a number of important potential therapeutic reactivities such as anti-tumor promotion, carcinogenesis suppression, and anti-oxidant and anti-inflammatory activities. Additional properties such as cytotoxicity, bitterness, and repellency are suggestive of a role in plant defence, but we also discuss their localization to the exterior of foliar secretory cavity lumina, and suggest they may also protect secretory cells from toxic terpenes housed within these structures. Finally we discuss how the use of a recently developed protocol to isolate secretory cavities in a functional state could be used in conjunction with systems biology approaches to help characterize their biosynthesis and roles in plants. Copyright © 2011 Elsevier Ltd. All rights reserved.

Substituent effects and pH profiles for stability constants of arylboronic acid diol esters.

PubMed

Martínez-Aguirre, Mayte A; Villamil-Ramos, Raul; Guerrero-Alvarez, Jorge A; Yatsimirsky, Anatoly K

2013-05-17

Stability constants of boronic acid diol esters in aqueous solution have been determined potentiometrically for a series of meta-, para-substituted phenylboronic acids and diols of variable acidity. The constants β(11-1) for reactions between neutral forms of reactants producing the anionic ester plus proton follow the Hammett equation with ρ depending on pKa of diol and varying from 2.0 for glucose to 1.29 for 4-nitrocatechol. Observed stability constants (K(obs)) measured by UV-vis and fluorometric titrations at variable pH for esters of 4,5-dihydroxy-1,3-benzenedisulfonate (Tiron) generally agree with those expected on the basis of β(11-1) values, but the direct fitting of K(obs) vs pH profiles gives shifted pKa values both for boronic acids and diol as a result of significant interdependence of fitting parameters. The subsituent effects on absorption and fluorescence spectra of Tiron arylboronate esters are characterized. The K(obs) for Tiron determined by (11)B NMR titrations are approximately 1 order of magnitude smaller than those determined by UV-vis titrations under identical conditions. A general equation, which makes possible an estimate of β(11-1) for any pair of boronic acid and diol from their pKa values, is proposed on the basis of established Brönsted-type correlation of Hammett parameters for β(11-1) with acidity of diols. The equation allows one to calculate stability constants expected only on basis of acid-base properties of the components, thus permitting more strict evaluation of contributions of additional factors such as steric or charge effects to the ester stability.

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

Code of Federal Regulations, 2013 CFR

2013-04-01

... from edible fats and oils. 172.225 Section 172.225 Food and Drugs FOOD AND DRUG ADMINISTRATION... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in food, subject to the...

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

Code of Federal Regulations, 2012 CFR

2012-04-01

... from edible fats and oils. 172.225 Section 172.225 Food and Drugs FOOD AND DRUG ADMINISTRATION... Methyl and ethyl esters of fatty acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in food, subject to the...

Glycidyl fatty acid esters in food by LC-MS/MS: method development.

PubMed

Becalski, A; Feng, S Y; Lau, B P-Y; Zhao, T

2012-07-01

An improved method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the analysis of glycidyl fatty acid esters in oils was developed. The method incorporates stable isotope dilution analysis (SIDA) for quantifying the five target analytes: glycidyl esters of palmitic (C16:0), stearic (C18:0), oleic (C18:1), linoleic (C18:2) and linolenic acid (C18:3). For the analysis, 10 mg sample of edible oil or fat is dissolved in acetone, spiked with deuterium labelled analogs of glycidyl esters and purified by a two-step chromatography on C18 and normal silica solid phase extraction (SPE) cartridges using methanol and 5% ethyl acetate in hexane, respectively. If the concentration of analytes is expected to be below 0.5 mg/kg, 0.5 g sample of oil is pre-concentrated first using a silica column. The dried final extract is re-dissolved in 250 μL of a mixture of methanol/isopropanol (1:1, v/v), 15 μL is injected on the analytical C18 LC column and analytes are eluted with 100% methanol. Detection of target glycidyl fatty acid esters is accomplished by LC-MS/MS using positive ion atmospheric pressure chemical ionization operating in Multiple Reaction Monitoring mode monitoring 2 ion transitions for each analyte. The method was tested on replicates of a virgin olive oil which was free of glycidyl esters. The method detection limit was calculated to be in the range of 70-150 μg/kg for each analyte using 10 mg sample and 1-3 μg/kg using 0.5 g sample of oil. Average recoveries of 5 glycidyl esters spiked at 10, 1 and 0.1 mg/kg were in the range 84% to 108%. The major advantage of our method is use of SIDA for all analytes using commercially available internal standards and detection limits that are lower by a factor of 5-10 from published methods when 0.5 g sample of oil is used. Additionally, MS/MS mass chromatograms offer greater specificity than liquid chromatography-mass spectrometry operated in selected ion monitoring mode. The method will be applied to

Enzymatic production of monoacylglycerols containing polyunsaturated fatty acids through an efficient glycerolysis system.

PubMed

Yang, Tiankui; Rebsdorf, Morten; Engelrud, Ulrik; Xu, Xuebing

2005-03-09

The aim of the study was to develop an efficient glycerolysis system for the enzymatic production of monoacylglycerols (MAGs) containing polyunsaturated fatty acids. Glycerolysis has been widely applied in industry for the chemical production of food MAGs under high temperature. The enzymatic glycerolysis system at 40-70 degrees C is unfortunately a multiphase system, which leads to the lower reaction efficiency. A tert-butyl alcohol system was developed after careful evaluation and more than 20-fold of the reaction efficiency from this system was obtained compared to the solvent-free system. Novozym 435 was employed as a catalyst in the glycerolysis from the screening. In the batch reaction system with tert-butyl alcohol, temperature higher than 40 degrees C was favored. The glycerol/oil ratio was best in the study with 4.5 while the solvent weight ratio from 1 to 3 had little effect. In general, 60-70% yield can be obtained at 2 h in the stirred tank reactor. The continuous glycerolysis was conducted in a packed bed reactor. MAG yield up to 70% was reached at 30-40 min residence time. The continuous glycerolysis was more sensitive to the amount of tert-butyl alcohol, and in the weight ratio to oil more than 2 was favored. The continuous process was optimized with the assistance of response surface methodology. Optimal conditions for the packed bed reactor after all considerations were recommended as glycerol/oil 4:1 (mol/mol), temperature 40 degrees C, and residence time 45 min. The operation stability study showed that there was no slight reduction of reaction performance at more than 30 days, implying a high feasibility in practical applications.

Effects of high-melting methyl esters on crystallization properties of fatty acid methyl ester mixtures

USDA-ARS?s Scientific Manuscript database

Biodiesel is a renewable alternative diesel fuel made from vegetable oils and animal fats. The most common form of biodiesel in the United States are fatty acid methyl esters (FAME) from soybean, canola, and used cooking oils, waste greases, and tallow. Cold flow properties of biodiesel depend on th...

40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

Code of Federal Regulations, 2011 CFR

2011-07-01

... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic... identified generically as alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction...

40 CFR 721.6477 - Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic...

Code of Federal Regulations, 2010 CFR

2010-07-01

... with ethoxylated fatty alcohols, reaction products with maleic anhydride. 721.6477 Section 721.6477... Alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction products with maleic... identified generically as alkyl polycarboxylic acids, esters with ethoxylated fatty alcohols, reaction...

21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

Code of Federal Regulations, 2013 CFR

2013-04-01

... chloride copolymer articles complying with § 177.1980 of this chapter that contact food of Types I, II, IV... 1,050 to 1,700. The esters are produced by the reaction of either ethylene glycol or glycerol with... chain alpha-olefins, the unreacted carboxylic acids in the formation of the glycerol esters being...

21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... chloride copolymer articles complying with § 177.1980 of this chapter that contact food of Types I, II, IV... 1,050 to 1,700. The esters are produced by the reaction of either ethylene glycol or glycerol with... chain alpha-olefins, the unreacted carboxylic acids in the formation of the glycerol esters being...

21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

Code of Federal Regulations, 2012 CFR

2012-04-01

... chloride copolymer articles complying with § 177.1980 of this chapter that contact food of Types I, II, IV... 1,050 to 1,700. The esters are produced by the reaction of either ethylene glycol or glycerol with... chain alpha-olefins, the unreacted carboxylic acids in the formation of the glycerol esters being...

21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... chloride copolymer articles complying with § 177.1980 of this chapter that contact food of Types I, II, IV... 1,050 to 1,700. The esters are produced by the reaction of either ethylene glycol or glycerol with... chain alpha-olefins, the unreacted carboxylic acids in the formation of the glycerol esters being...

Isolation and characterization of esters of indole-3-acetic acid from the liquid endosperm of the horse chestnut (Aesculus species)

NASA Technical Reports Server (NTRS)

Domagalski, W.; Schulze, A.; Bandurski, R. S.

1987-01-01

Esters of indole-3-acetic acid were extracted and purified from the liquid endosperm of immature fruits of various species of the horse chestnut (Aesculus parviflora, A. baumanni, A. pavia rubra, and A. pavia humulis). The liquid endosperm contained, at least 12 chromatographically distinct esters. One of these compounds was purified and characterized as an ester of indole-3-acetic acid and myo-inositol. A second compound was found to be an ester of indole-3-acetic acid and the disaccharide rutinose (glucosyl-rhamnose). A third compound was partially characterized as an ester of indole-3-acetic acid and a desoxyaminohexose.

Selective Formation of Secondary Amides via the Copper-Catalyzed Cross-Coupling of Alkylboronic Acids with Primary Amides

PubMed Central

Rossi, Steven A.; Shimkin, Kirk W.; Xu, Qun; Mori-Quiroz, Luis M.; Watson, Donald A.

2014-01-01

For the first time, a general catalytic procedure for the cross coupling of primary amides and alkylboronic acids is demonstrated. The key to the success of this reaction was the identification of a mild base (NaOSiMe3) and oxidant (di-tert-butyl peroxide) to promote the copper-catalyzed reaction in high yield. This transformation provides a facile, high-yielding method for the mono-alkylation of amides. PMID:23611591

Lipase-catalyzed production of short-chain acids terpenyl esters of interest to the food industry.

PubMed

Laboret, F; Perraud, R

1999-12-01

The production of low molecular weight esters as flavor compounds by biotechnological processes has a potential interest for the food industry. The use of natural available substrates and enzymes is an essential part of the process design, because the products may obtain natural label. In this study, direct esterification of citronellol and geraniol with short-chain fatty acids catalyzed by free lipase from Mucor miehei was performed with high yields in n-hexane. The effects of the acid:alcohol ratio on the bioconversion rate of increasing chain length esters was investigated. To reach the optimum yield, substrates and enzyme concentration were determined. The inhibiting effects of acid are strongly attenuated by reducing the quantity of acid and increasing the amount of enzyme in media following the optimum values. Improvements have been made to increase the ester purity. The consumption of excess substrate by adding calculated amounts of acid gives a 10% yield enhancement, and leads to 100% pure terpenyl esters. The first steps to a scale-up application were attempted using a reactor that allowed us to produce ester quantities up to 100 cm3. Separation and purification of the products were treated with success, underlining the lipase stability and efficiency under the conditions of this study. The ability to recover the enzyme, and reusing it in bioconversions, plays a major role in reducing the cost of the overall process.

Gastroprotective Activity of Ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylidene) Amino]benzoate against Ethanol-Induced Gastric Mucosal Ulcer in Rats

PubMed Central

Halabi, Mohammed Farouq; Shakir, Raied Mustafa; Bardi, Daleya Abdulaziz; Al-Wajeeh, Nahla Saeed; Ablat, Abdulwali; Hassandarvish, Pouya; Hajrezaie, Maryam; Norazit, Anwar; Abdulla, Mahmood Ameen

2014-01-01

Background The study was carried out to determine the cytotoxic, antioxidant and gastro-protective effect of ethyl-4-[(3,5-di-tert-butyl-2-hydroxybenzylid ene)amino] benzoate (ETHAB) in rats. Methodology/Principal Findings The cytotoxic effect of ETHAB was assessed using a MTT cleavage assay on a WRL68 cell line, while its antioxidant activity was evaluated in vitro. In the anti-ulcer study, rats were divided into six groups. Group 1 and group 2 received 10% Tween 20 (vehicle). Group 3 received 20 mg/kg Omeprazole. Groups 4, 5 and 6 received ETHAB at doses of 5, 10, and 20 mg/kg, respectively. After an hour, group 1 received the vehicle. Groups 2–6 received absolute ethanol to induce gastric mucosal lesions. In the WRL68 cell line, an IC50 of more than 100 µg/mL was observed. ETHAB results showed antioxidant activity in the DPPH, FRAP, nitric oxide and metal chelating assays. There was no acute toxicity even at the highest dosage (1000 mg/kg). Microscopy showed that rats pretreated with ETHAB revealed protection of gastric mucosa as ascertained by significant increases in superoxide dismutase (SOD), pH level, mucus secretion, reduced gastric lesions, malondialdehyde (MDA) level and remarkable flattened gastric mucosa. Histologically, pretreatment with ETHAB resulted in comparatively better gastric protection, due to reduction of submucosal edema with leucocyte infiltration. PAS staining showed increased intensity in uptake of Alcian blue. In terms of immunohistochemistry, ETHAB showed down-expression of Bax proteins and over-expression of Hsp70 proteins. Conclusion/Significance The gastroprotective effect of ETHAB may be attributed to antioxidant activity, increased gastric wall mucus, pH level of gastric contents, SOD activity, decrease in MDA level, ulcer area, flattening of gastric mucosa, reduction of edema and leucocyte infiltration of the submucosal layer, increased PAS staining, up-regulation of Hsp70 protein and suppressed expression of Bax. Key words

Effect of antioxidants on the performance and emission characteristics of a diesel engine fuelled by waste cooking sunflower methyl ester

NASA Astrophysics Data System (ADS)

Reddy, V. Puneeth Kumar; Senthil Kumar, D.; Thirumalini, S.

2018-02-01

Biodiesel is a renewable, biodegradable fuel produced from vegetable oils and animal fats. Nonetheless, its extensive utilization is impeded by the auto-oxidation resulting in degradation of the fuel. Adding antioxidants to the biodiesel is a potential solution, but it might have an effect on the clean-burning characteristics of the fuel. This paper investigates the effect of antioxidants on the performance and emission characteristics of a diesel engine fuelled by the waste cooking sunflower methyl ester. The fuel samples tested include B10, B20, B30 and B40, among which B20 produced the best possible results. Antioxidants 2, 6-ditert-butyl-4-methylphenol (BHA) and 2(3)-tert-butyl-4-methoxy phenol (BHT) of two concentrations 1000 ppm, 2000 ppm were added to B20 to evaluate the effectiveness. B20BHA1000 had the best effect with an average decrease of 5.035%, 2.02% in brake specific fuel consumption (BSFC) and exhaust gas temperature (EGT) compared to B20. Regarding the emission characteristics it was observed that B20BHA1000 had produced an increase of 7.21%, 27.79% in NOx and smoke emissions and a decrease of 33.33% in HC emissions when compared to B20. On the whole, without any requirement of alteration in the diesel engines, B20 blends with antioxidant can be utilized as fuel.

Synthesis, characterization and application of lipase-conjugated citric acid-coated magnetic nanoparticles for ester synthesis using waste frying oil.

PubMed

Patel, Unisha; Chauhan, Kishor; Gupte, Shilpa

2018-04-01

In the present work, magnetic nanoparticles (MNPs) were prepared by chemical precipitation of trivalent and divalent iron ions which were functionalized using citric acid. The bacterial isolate Staphylococcus epidermidis KX781317 was isolated from oil-contaminated site. The isolate produced lipase, which was purified and immobilized on magnetic nanoparticles (MNPs) for ester synthesis from waste frying oil (WFO). The characterization of MNPs employed conventional TEM, XRD and FTIR techniques. TEM analysis of MNPs showed the particle size in the range of 20-50 nm. FTIR spectra revealed the binding of citric acid to Fe 3 O 4 and lipase on citric acid-coated MNPs. The citric acid-coated MNPs and lipase-conjugated citric acid-coated MNPs had similar XRD patterns which indicate MNPs could preserve their magnetic properties. The maximum immobilization efficiency 98.21% of lipase-containing citric acid-coated MNPs was observed at ratio 10:1 of Cit-MNPs:lipase. The pH and temperature optima for lipase conjugated with Cit-MNPs were 7 and 35 °C, respectively. Isobutanol was found to be an effective solvent for ester synthesis and 1:2 ratio of oil:alcohol observed significant for ester formation. The ester formation was determined using TLC and the % yield of ester conversion was calculated. The rate of ester formation is directly proportional to the enzyme load. Formed esters were identified as isobutyl laurate ester and isobutyl myristate ester through GC-MS analysis.

27 CFR 21.118 - Methyl n-butyl ketone.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Methyl n-butyl ketone. 21.118 Section 21.118 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....118 Methyl n-butyl ketone. (a) Acidity (as acetic acid). 0.02 percent by weight, maximum. (b) Color...

27 CFR 21.118 - Methyl n-butyl ketone.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Methyl n-butyl ketone. 21.118 Section 21.118 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE BUREAU....118 Methyl n-butyl ketone. (a) Acidity (as acetic acid). 0.02 percent by weight, maximum. (b) Color...

Method of making alkyl esters

DOEpatents

Elliott, Brian

2010-09-14

Methods of making alkyl esters are described herein. The methods are capable of using raw, unprocessed, low-cost feedstocks and waste grease. Generally, the method involves converting a glyceride source to a fatty acid composition and esterifying the fatty acid composition to make alkyl esters. In an embodiment, a method of making alkyl esters comprises providing a glyceride source. The method further comprises converting the glyceride source to a fatty acid composition comprising free fatty acids and less than about 1% glyceride by mass. Moreover, the method comprises esterifying the fatty acid composition in the presence of a solid acid catalyst at a temperature ranging firm about 70.degree. C. to about 120.degree. C. to produce alkyl esters, such that at least 85% of the free fatty acids are converted to alkyl esters. The method also incorporates the use of packed bed reactors for glyceride conversion and/or fatty acid esterification to make alkyl esters.

Impact of thermooxidation of phytosteryl and phytostanyl fatty acid esters on cholesterol micellarization in vitro.

PubMed

Scholz, Birgit; Weiherer, Renate; Engel, Karl-Heinz

2017-09-01

The effects of thermooxidation of a phytosteryl/-stanyl and a phytostanyl fatty acid ester mixture on cholesterol micellarization were investigated using an in vitro digestion model simulating enzymatic hydrolysis by cholesterol esterase and subsequent competition of the liberated phytosterols/-stanols with cholesterol for incorporation into mixed micelles. As a first step, relationships between different doses of the ester mixtures and the resulting micellarized cholesterol were established. Subsequent subjection of the thermooxidized ester mixtures to the in vitro digestion model resulted in three principal observations: (i) thermal treatment of the ester mixtures led to substantial decreases of the intact esters, (ii) in vitro digestion of cholesterol in the presence of the thermooxidized ester mixtures resulted in significant increases of cholesterol micellarization, and (iii) the extents of the observed effects on cholesterol micellarization were strongly associated to the remaining contents of intact esters. The loss of efficacy to inhibit cholesterol micellarization due to thermally induced losses of intact esters corresponded to a loss of efficacy that would have been induced by an actual removal of these amounts of esters prior to the in vitro digestion. The obtained results suggest that in particular oxidative modifications of the fatty acid moieties might be responsible for the observed increases of cholesterol micellarization. Copyright © 2017 Elsevier Inc. All rights reserved.

Gas chromatographic-mass spectrometric determination of alkylphosphonic acids from aqueous samples by ion-pair solid-phase extraction on activated charcoal and methylation.

PubMed

Vijaya Saradhi, U V R; Prabhakar, S; Jagadeshwar Reddy, T; Murty, M R V S

2007-07-20

In the present paper, we report an improved ion-pair solid-phase extraction (IP-SPE) method for the analysis of alkylphosphonic acids, namely, methyl, ethyl and propylphosphonic acids, present in the aqueous sample. The aqueous sample was mixed with an ion-pair reagent, phenyltrimethylammonium hydroxide (PTMAH) and passed through activated charcoal SPE cartridge. The retained chemicals in the cartridge were extracted with methanol and analysed by gas chromatography-mass spectrometry (GC-MS) under the electron impact ionization (EI) mode. The analytes were converted to their methyl esters by pyrolytic methylation in the hot GC injection port. The recoveries of alkylphosphonic acids were above 95% and the minimum detection limits were as low as 10 ng/mL. The recovery of the test chemicals was tested with solvents, dichloromethane, n-hexane, ethyl acetate, acetone, acetonitrile and methanol. The chemicals could be efficiently extracted by the hydrophilic solvents. The method did not work at the highly acidic pH (when acidified with dilute HCl) but worked well from pH 4.0 to 14.0. The present method was also tested with other tetra-(methyl, ethyl, propyl and n-butyl)ammonium hydroxides. The test chemicals were not converted to their methyl and ethyl esters with tetramethyl and tetraethylammonium hydroxides, whereas they were converted to their corresponding propyl and n-butyl esters with tetrapropyl and tetra(n-butyl)ammonium hydroxides. The method was also applied to two highly cross-linked polymeric sorbents DSC-6S and Oasis HLB. The recovery of the chemicals on these sorbents was observed to be poor. Methylation using phenyltrimethylammonium hydroxide is non-hazardous and advantageous over methylation using diazomethane. The method was applied to the analysis of aqueous samples given in one of the official proficiency tests conducted by the Organization for the Prohibition of Chemical Weapons and all the spiked chemicals were identified as methyl esters.

Synthesis of palm oil fatty acid and trimethylolpropane based ester for biolubricant base stocks

NASA Astrophysics Data System (ADS)

Nor, Nurazira Mohd; Derawi, Darfizzi; Salimon, Jumat

2018-04-01

RBD palm oil become one of the interesting renewable resources in biolubricant application. However, palm oil cannot be used directly as lubricant due to some performance limitations such as thermal and oxidative stability. This drawback can be overcome by chemical modification through esterification with polyhydric alcohol such as trimethylolpropane (TMP). The synthesis of ester was carried out via esterification of palm oil fatty acid (POFA) with TMP in the presence of 2% sulphuric acid as catalyst at 150 °C for 5 hours. Gas Chromatography equipped with a Flame Ionization Detector (GC-FID) was used to determine the percentage composition of POTMP ester. The structure confirmation of POTMP ester was proven by Fourier Transformation Infra-Red (FTIR), proton and carbon Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) spectroscopy analysis. The result showed that POTMP ester has successfully synthesized with 97.7% composition of triesters (TE), proved by GC chromatogram. Presence of ester group also evidenced by 1H NMR at 2.27-2.30 ppm and 13C NMR at 173.52-173.54 ppm. The percentage yield of POTMP ester produced was 82% and exist in liquid form at room temperature.

Chemical aspects of silicon-containing bilayer resists

NASA Astrophysics Data System (ADS)

Boardman, Larry D.; Kessel, Carl R.; Rhyner, Steven J.

1999-06-01

We have prepare several novel silicon-containing polymers containing both low Ea and high Ea protecting groups, and we have evaluated these materials at both 193 nm. Low Ea acetal-containing polymers were prepared by reacting poly(4-vinylphenol) with novel silyl enol ethers. The ease of protecting group cleavage in these materials is manifested in the immediate formation of a strong latent image after exposure. High Ea polymers were prepared by introducing tertiary esters which contain the tris(trimethylsilyl)silyl group, and both methacrylate copolymers and norbornene-maleic anhydride copolymers containing this group have been synthesized. Both of these materials show good oxygen plasma etch resistance, with the latter demonstrating superior adhesion to poly(4- vinylphenol) planarizing layers. The tris(trimethylsilyl)silyl group imparts a high degree of hydrophobicity to coatings of many of these materials. Acid- catalyzed deprotection of these tertiary esters affords the corresponding carboxylic acids and 1-silyl-3-methylbutenes, and the liberation of these olefins is significantly faster than the loss of isobutylene from the tert-butyl analogs.

Combined prenatal and postnatal butyl paraben exposure produces autism-like symptoms in offspring: comparison with valproic acid autistic model.

PubMed

Ali, Elham H A; Elgoly, Amany H Mahmoud

2013-10-01

The aim of this work is to evaluate the impact of butyl paraben (BP) in brain of the pups developed for mothers administered BP from early pregnancy till weaning and its effect on studying the behavior, brain neurotransmitters and brain derived neurotrophic factor BDNF via comparing the results with valproic acid (VA) autistic-rat model preparing by a single oral injection dose of VA (800 mg/kg b.wt) at the 12.5 days of gestation. Butyl paraben was orally and subcutaneously administered (200 mg/kg b.wt) to pregnant rats from gestation day 1 to lactation day 21. The offspring male rats were subjected at the last 3 days of lactation to Morris water maze and three chamber sociability test then decapitated and the brain was excised and dissected to the cortex, hippocampus, cerebellum, midbrain and pons for the determination of norepinephrine, dopamine and serotonin (NE, DA and 5-HT) and cortex amino acids and whole brain BDNF. The results showed similar social and learning and memory behavioral deficits in VA rat model and the butyl paraben offspring in comparison with the controls. Also, some similar alterations were observed in monoamine content, amino acids and BDNF factor in the autistic-like model and butyl paraben offspring in comparison with the controls. The alterations were recorded notably in hippocampus and pons NE, midbrain DA, hippocampus and midbrain 5-HT, and frontal cortex GABA and asparagine. These data suggest that prenatal exposure to butyl paraben induced neuro-developmental disorders similar to some of the neurodevelopmental disorders observed in the VA model of autism. © 2013 Elsevier Inc. All rights reserved.

40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

Code of Federal Regulations, 2011 CFR

2011-07-01

... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 2-(3-phenylbutylidene...

40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

Code of Federal Regulations, 2010 CFR

2010-07-01

... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 2-(3-phenylbutylidene...

Myo-inositol esters of indole-3-acetic acid are endogenous components of Zea mays L. shoot tissue

NASA Technical Reports Server (NTRS)

Chisnell, J. R.

1984-01-01

Indole-3-acetyl-myo-inositol esters have been demonstrated to be endogenous components of etiolated Zea mays shoots tissue. This was accomplished by comparison of the putative compounds with authentic, synthetic esters. The properties compared were liquid and gas-liquid chromatographic retention times and the 70-ev mass spectral fragmentation pattern of the pentaacetyl derivative. The amount of indole-3-acetyl-myo-inositol esters in the shoots was determined to be 74 nanomoles per kilogram fresh weight as measured by isotope dilution, accounting for 19% of the ester indole-3-acetic acid of the shoot. This work is the first characterization of an ester conjugate of indole-3-acetate acid from vegetative shoot tissue using multiple chromatographic properties and mass spectral identification. The kernel and the seedling shoot both contain indole-3-acetyl-myo-inositol esters, and these esters comprise approximately the same percentage of the total ester content of the kernel and of the shoot.

Isolation and Characterization of Esters of Indole-3-Acetic Acid from the Liquid Endosperm of the Horse Chestnut (Aesculus species) 1

PubMed Central

Domagalski, Wojciech; Schulze, Aga; Bandurski, Robert S.

1987-01-01

Esters of indole-3-acetic acid were extracted and purified from the liquid endosperm of immature fruits of various species of the horse chestnut (Aesculus parviflora, A. baumanni, A.pavia rubra, and A. pavia humulis). The liquid endosperm contained, at least 12 chromatographically distinct esters. One of these compounds was purified and characterized as an ester of indole-3-acetic acid and myo-inositol. A second compound was found to be an ester of indole-3-acetic acid and the disaccharide rutinose (glucosyl-rhamnose). A third compound was partially characterized as an ester of indole-3-acetic acid and a desoxyaminohexose. PMID:11539676

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

Code of Federal Regulations, 2012 CFR

2012-04-01

... propylene glycol. 172.850 Section 172.850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be safely used in food in accordance with the following prescribed conditions: (a) The...

21 CFR 172.850 - Lactylated fatty acid esters of glycerol and propylene glycol.

Code of Federal Regulations, 2013 CFR

2013-04-01

... propylene glycol. 172.850 Section 172.850 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... esters of glycerol and propylene glycol. The food additive lactylated fatty acid esters of glycerol and propylene glycol may be safely used in food in accordance with the following prescribed conditions: (a) The...

Lysis of Bacillus subtilis Cells by Glycerol and Sucrose Esters of Fatty Acids

PubMed Central

Tsuchido, Tetsuaki; Ahn, Yung-Hoon; Takano, Mitsuo

1987-01-01

The lytic action of glycerol and sucrose esters of fatty acids with different carbon chain lengths on the exponentially growing cells of Bacillus subtilis 168 was investigated. Of each series of esters, glycerol dodecanoate and sucrose hexadecanoate were the most active. Lysis at 1 h after the addition of 0.1 mM glycerol dodecanoate or 20 μg of sucrose hexadecanoate per ml was 81 or 79%, respectively, as evaluated by the reduction in optical density. During this treatment a great loss of viability occurred that preceded lysis. The results that were obtained suggest that autolysis is induced by these esters. The esters caused morphological changes in the cells, but a seeming adaptation of the cells to esters was seen. Images PMID:16347300

A PHYSIOLOGICALLY-BASED PHARMACOKINETIC MODEL FOR INTRAVENOUS AND INHALATION-ROUTE PHARMACOKINETICS OF BUTYL ACETATE AND METABOLITES N-BUTANOL AND N-BUTYRIC ACID

EPA Science Inventory

Risk assessment for n-butyl acetate and metabolites n-butanol and n-butyric acid (the butyl series) can be accomplished with limited toxicity data and pharmacokinetic data for each compound through application of the "family approach" (Barton et al., 2000). The necessary quantita...

Lewis base activation of Lewis acids: catalytic, enantioselective addition of glycolate-derived silyl ketene acetals to aldehydes.

PubMed

Denmark, Scott E; Chung, Won-Jin

2008-06-20

A catalytic system involving silicon tetrachloride and a chiral, Lewis basic bisphosphoramide catalyst is effective for the addition of glycolate-derived silyl ketene acetals to aldehydes. It was found that the sense of diastereoselectivity could be modulated by changing the size of the substituents on the silyl ketene acetals. In general, the trimethylsilyl ketene acetals derived from methyl glycolates with a large protecting group on the alpha-oxygen provide enantiomerically enriched alpha,beta-dihydroxy esters with high syn-diastereoselectivity, whereas the tert-butyldimethylsilyl ketene acetals derived from bulky esters of alpha-methoxyacetic acid provide enantiomerically enriched alpha,beta-dihydroxy esters with high anti-diastereoselecitvity.

The synthesis and structure of a potential immunosuppressant: N-mycophenoyl malonic acid dimethyl ester

NASA Astrophysics Data System (ADS)

Siebert, Agnieszka; Cholewiński, Grzegorz; Garwolińska, Dorota; Olejnik, Adrian; Rachoń, Janusz; Chojnacki, Jarosław

2018-01-01

The synthesis of a potential immunosuppressant, i.e. dimethyl ester of N-mycophenoyl malonic acid was optimized in the reaction of mycophenolic acid (MPA) with amino malonic dimethyl ester in the presence of propanephosphonic anhydride (T3P) as a coupling reagent. The structural properties of the obtained MPA derivative were investigated by NMR, MS and single crystal X-ray diffraction methods. Theoretical considerations of conformational flexibility based on DFT calculations are presented.

Characterizing Effects of Nitric Oxide Sterilization on tert-Butyl Acrylate Shape Memory Polymers

NASA Astrophysics Data System (ADS)

Phillippi, Ben

As research into the potential uses of shape memory polymers (SMPs) as implantable medical devices continues to grow and expand, so does the need for an accurate and reliable sterilization mechanism. The ability of an SMP to precisely undergo a programmed shape change will define its ability to accomplish a therapeutic task. To ensure proper execution of the in vivo shape change, the sterilization process must not negatively affect the shape memory behavior of the material. To address this need, this thesis investigates the effectiveness of a benchtop nitric oxide (NOx) sterilization process and the extent to which the process affects the shape memory behavior of a well-studied tert-Butyl Acrylate (tBA) SMP. Quantifying the effects on shape memory behavior was performed using a two-tiered analysis. A two-tiered study design was used to determine if the sterilization process induced any premature shape recovery and to identify any effects that NOx has on the overall shape memory behavior of the foams. Determining the effectiveness of the NOx system--specially, whether the treated samples are more sterile/less contaminated than untreated--was also performed with a two-tiered analysis. In this case, the two-tiered analysis was employed to have a secondary check for contamination. To elaborate, all of the samples that were deemed not contaminated from the initial test were put through a second sterility test to check for contamination a second time. The results of these tests indicated the NOx system is an effective sterilization mechanism and the current protocol does not negatively impact the shape memory behavior of the tBA SMP. The samples held their compressed shape throughout the entirety of the sterilization process. Additionally, there were no observable impacts on the shape memory behavior induced by NOx. Lastly, the treated samples demonstrated lower contamination than the untreated. This thesis demonstrates the effectiveness of NOx as a laboratory scale

Fatty acid methyl ester profiles of bat wing surface lipids.

PubMed

Pannkuk, Evan L; Fuller, Nathan W; Moore, Patrick R; Gilmore, David F; Savary, Brett J; Risch, Thomas S

2014-11-01

Sebocytes are specialized epithelial cells that rupture to secrete sebaceous lipids (sebum) across the mammalian integument. Sebum protects the integument from UV radiation, and maintains host microbial communities among other functions. Native glandular sebum is composed primarily of triacylglycerides (TAG) and wax esters (WE). Upon secretion (mature sebum), these lipids combine with minor cellular membrane components comprising total surface lipids. TAG and WE are further cleaved to smaller molecules through oxidation or host enzymatic digestion, resulting in a complex mixture of glycerolipids (e.g., TAG), sterols, unesterified fatty acids (FFA), WE, cholesteryl esters, and squalene comprising surface lipid. We are interested if fatty acid methyl ester (FAME) profiling of bat surface lipid could predict species specificity to the cutaneous fungal disease, white nose syndrome (WNS). We collected sebaceous secretions from 13 bat spp. using Sebutape(®) and converted them to FAME with an acid catalyzed transesterification. We found that Sebutape(®) adhesive patches removed ~6× more total lipid than Sebutape(®) indicator strips. Juvenile eastern red bats (Lasiurus borealis) had significantly higher 18:1 than adults, but 14:0, 16:1, and 20:0 were higher in adults. FAME profiles among several bat species were similar. We concluded that bat surface lipid FAME profiling does not provide a robust model predicting species susceptibility to WNS. However, these results provide baseline data that can be used for lipid roles in future ecological studies, such as life history, diet, or migration.

p-tert-Butylcalix[6]arene hexacarboxylic acid as host for Pb(ii), Sr(ii) and Ba(ii)†

PubMed Central

Adhikari, Birendra Babu; Zhao, Xiang; Derakhshan, Shahab

2015-01-01

p-tert-Butylcalixarene hexacarboxylic acid initially binds with low symmetry, to later adopt a highly symmetric up-down alternating conformation in the presence of Pb, Sr or Ba. The conformational dynamics for the three ions are distinct, from 15 hours, to 20 days, to 38 days, respectively. PMID:25198172

Phytyl Fatty Acid Esters in the Pulp of Bell Pepper (Capsicum annuum).

PubMed

Krauß, Stephanie; Hammann, Simon; Vetter, Walter

2016-08-17

Phytyl fatty acid esters (PFAE) are esters of fatty acids with the isoprenoid alcohol phytol (3,7R,11R,15-tetramethylhexadec-2E-enol). In this study, PFAE were identified and quantified in bell pepper using gas chromatography with mass spectrometry (GC-MS). All red (n = 14) and yellow (n = 6) samples contained six or seven PFAE at 0.9-11.2 mg/100 g fresh weight. By contrast, PFAE were not detected in green bell pepper samples (n = 3). PFAE might eventually be a source for bioavailable phytol, which can be transformed into phytanic acid by humans. Phytanic acid cannot be properly degraded by patients who suffer from Refsum's disease (tolerable daily intake (TDI) ≤ 10 mg of phytanic acid). The phytol moiety of the PFAE (0.4-5.4 mg/100 g fresh weight) would contribute up to ∼50% to the TDI with the consumption of only one portion of bell pepper fruit pulp.

21 CFR 176.200 - Defoaming agents used in coatings.

Code of Federal Regulations, 2011 CFR

2011-04-01

... alcohol tert-Butyl alcohol Butyl stearate Castor oil, sulfated, ammonium, potassium, or sodium salt Cetyl... palmitate Mineral oil Mustardseed oil, sulfated, ammonium, potassium, or sodium salt Myristyl alcohol... hydrocarbons As defined in § 178.3650 of this chapter. Oleic acid, sulfated, ammonium, potassium, or sodium...

21 CFR 176.200 - Defoaming agents used in coatings.

Code of Federal Regulations, 2010 CFR

2010-04-01

... alcohol tert-Butyl alcohol Butyl stearate Castor oil, sulfated, ammonium, potassium, or sodium salt Cetyl... palmitate Mineral oil Mustardseed oil, sulfated, ammonium, potassium, or sodium salt Myristyl alcohol... hydrocarbons As defined in § 178.3650 of this chapter. Oleic acid, sulfated, ammonium, potassium, or sodium...

Synthesis of t-Butyl (2R)-Hydroxyisovalerate, A Precursor of Aureobasidin B

NASA Astrophysics Data System (ADS)

Maharani, R.; Puspitasari, D.; Taufiqqurahman; Huspa, D. H. P.; Hidayat, A. T.; Sumiarsa, D.; Hidayat, I. W.

2017-02-01

Aureobasidins are a family of cyclodepsipeptides have antifungal properties. They were isolated from the black yeast Aureobasidium pullulans R106 and over 30 derivatives have been successfully characterized. There are few publications reporting the total synthesis of aureobasidins. The limited reports of the synthesis of the aureobasidin derivatives are due to the difficult access to the preparations of precursors. The aim of this research is to synthesise a precursor of aureobasidin B, t-butyl (2R)-hydroxyisovalerate (t-Bu-Hiv), that is prepared for the total synthesis of aureobasidin B. The synthesis of AbB is planned to be undertaken by using a solid phase method, so the ester formation between t-Bu-Hiv and the Fmoc-β-hydroxymethylvaline will be carried out in solution phase to form depsidipeptide. The t-butyl group was used as protecting agent that is due to the straightforward elimination of the protecting group from the Fmoc-depsidipeptide. The t-Bu-Hiv acid was prepared from D-valine through diazotisation to form (2R)-acetyloxyisovaleric acid in 62.7% yield. Product of the first step was then protected by t-butyl group by using Boc-anhydride in t-butanol to give t-butil (2R)-acetyloxyisovalerate in 44% yield. In the last step, the acetyloxy group was eliminated by using potassium carbonate in methanol/water to give the desired product, t-Bu-Hiv in 33.5% yield. The t-Bu-Hiv is ready to be combined with Fmoc-β-hydroxymethylvaline to result in depsidipeptide that will be attached to the resin in the total synthesis of AbB. Each stage of this synthesis was controlled by thin layer chromatography and all products were purified by open column chromatography. All the synthesized products were characterized by various spectroscopic techniques, including infrared spectrophotometer, mass spectroscopy (ESI-MS), 1H-NMR and 13C-NMR.

Novel sustained-release dosage forms of proteins using polyglycerol esters of fatty acids.

PubMed

Yamagata, Y; Iga, K; Ogawa, Y

2000-02-03

In order to develop a novel delivery system for proteins based on polyglycerol esters of fatty acids (PGEFs), we studied a model system using interferon-alpha (IFN-alpha) as the test protein. A cylindrical matrix was prepared by a heat extrusion technique using a lyophilized powder of the protein and 11 different types of synthetic PGEFs, which varied in degree of glycerol polymerization (di- and tetra-), chain length of fatty acids (myristate, palmitate and stearate) and degree of fatty acid esterification (mono-, di- and tri-). In an in-vitro release study using an enzyme-linked immunosorbent assay (ELISA) as a detection method, the matrices prepared from a monoglyceride (used for comparison) and from diglycerol esters exhibited a biphasic release pattern with a large initial burst followed by slow release. In contrast, the matrices prepared from tetraglycerol esters showed a steady rate of release without a large initial burst. In an in vivo release study, initial bursts of IFN-alpha release were, also, dramatically reduced when the matrices were prepared from the tetraglycerol esters of palmitate and stearate, and the mean residence time (MRT) of IFN-alpha was prolonged, whereas the matrices prepared from monoglyceride and from diglycerol esters showed large initial bursts of IFN-alpha release. Since the release rates from the matrices prepared from the tetraglycerol esters of palmitate and stearate were governed by Jander's equation modified for a cylindrical matrix, the release from those matrices was concluded to be a diffusion-controlled process. The bioavailability of IFN-alpha after implantation of the matrix formulation prepared using all types of PGEFs, except for tetraglycerol triesters, was almost equivalent to that after injection of IFN-alpha solution; consequently, IFN-alpha in these matrices appears to remain stable during the release period.

Direct Determination of MCPD Fatty Acid Esters and Glycidyl Fatty Acid Esters in Vegetable Oils by LC–TOFMS

PubMed Central

Haines, Troy D.; Adlaf, Kevin J.; Pierceall, Robert M.; Lee, Inmok; Venkitasubramanian, Padmesh

2010-01-01

Analysis of MCPD esters and glycidyl esters in vegetable oils using the indirect method proposed by the DGF gave inconsistent results when salting out conditions were varied. Subsequent investigation showed that the method was destroying and reforming MCPD during the analysis. An LC time of flight MS method was developed for direct analysis of both MCPD esters and glycidyl esters in vegetable oils. The results of the LC–TOFMS method were compared with the DGF method. The DGF method consistently gave results that were greater than the LC–TOFMS method. The levels of MCPD esters and glycidyl esters found in a variety of vegetable oils are reported. MCPD monoesters were not found in any oil samples. MCPD diesters were found only in samples containing palm oil, and were not present in all palm oil samples. Glycidyl esters were found in a wide variety of oils. Some processing conditions that influence the concentration of MCPD esters and glycidyl esters are discussed. PMID:21350591

Molecular Basis of Prodrug Activation by Human Valacyclovirase, an [alpha]-Amino Acid Ester Hydrolase

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

Lai, Longsheng; Xu, Zhaohui; Zhou, Jiahai

2008-07-08

Chemical modification to improve biopharmaceutical properties, especially oral absorption and bioavailability, is a common strategy employed by pharmaceutical chemists. The approach often employs a simple structural modification and utilizes ubiquitous endogenous esterases as activation enzymes, although such enzymes are often unidentified. This report describes the crystal structure and specificity of a novel activating enzyme for valacyclovir and valganciclovir. Our structural insights show that human valacyclovirase has a unique binding mode and specificity for amino acid esters. Biochemical data demonstrate that the enzyme hydrolyzes esters of {alpha}-amino acids exclusively and displays a broad specificity spectrum for the aminoacyl moiety similar tomore » tricorn-interacting aminopeptidase F1. Crystal structures of the enzyme, two mechanistic mutants, and a complex with a product analogue, when combined with biochemical analysis, reveal the key determinants for substrate recognition; that is, a flexible and mostly hydrophobic acyl pocket, a localized negative electrostatic potential, a large open leaving group-accommodating groove, and a pivotal acidic residue, Asp-123, after the nucleophile Ser-122. This is the first time that a residue immediately after the nucleophile has been found to have its side chain directed into the substrate binding pocket and play an essential role in substrate discrimination in serine hydrolases. These results as well as a phylogenetic analysis establish that the enzyme functions as a specific {alpha}-amino acid ester hydrolase. Valacyclovirase is a valuable target for amino acid ester prodrug-based oral drug delivery enhancement strategies.« less

40 CFR 721.10457 - 1,2-Benzenedicarboxylic acid, mixed esters with benzyl alc., cyclohexanol, 2-ethyl-1-hexanol...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false 1,2-Benzenedicarboxylic acid, mixed... Substances § 721.10457 1,2-Benzenedicarboxylic acid, mixed esters with benzyl alc., cyclohexanol, 2-ethyl-1... reporting. (1) The chemical substance identified as 1,2-benzenedicarboxylic acid, mixed esters with benzyl...

40 CFR 721.10457 - 1,2-Benzenedicarboxylic acid, mixed esters with benzyl alc., cyclohexanol, 2-ethyl-1-hexanol...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false 1,2-Benzenedicarboxylic acid, mixed... Substances § 721.10457 1,2-Benzenedicarboxylic acid, mixed esters with benzyl alc., cyclohexanol, 2-ethyl-1... reporting. (1) The chemical substance identified as 1,2-benzenedicarboxylic acid, mixed esters with benzyl...

Dimer esters in α-pinene secondary organic aerosol: effect of hydroxyl radical, ozone, relative humidity and aerosol acidity

NASA Astrophysics Data System (ADS)

Kristensen, K.; Cui, T.; Zhang, H.; Gold, A.; Glasius, M.; Surratt, J. D.

2013-12-01

The formation of secondary organic aerosol (SOA) from both ozonolysis and hydroxyl radical (OH)-initiated oxidation of α-pinene under conditions of high nitric oxide (NO) concentrations with varying relative humidity (RH) and aerosol acidity was investigated in the University of North Carolina dual outdoor smog chamber facility. SOA formation from ozonolysis of α-pinene was enhanced relative to that from OH-initiated oxidation in the presence of initially high NO conditions. However, no effect of RH on SOA mass was evident. Ozone (O3)-initiated oxidation of α-pinene in the presence of ammonium sulfate (AS) seed coated with organic aerosol from OH-initiated oxidation of α-pinene showed reduced nucleation compared to ozonolysis in the presence of pure AS seed aerosol. The chemical composition of α-pinene SOA was investigated by ultra-performance liquid chromatography/electrospray ionization high-resolution quadrupole time-of-flight mass spectrometry (UPLC/ESI-HR-Q-TOFMS), with a focus on the formation of carboxylic acids and high-molecular weight dimer esters. A total of eight carboxylic acids and four dimer esters were identified, constituting between 8 and 12% of the total α-pinene SOA mass. OH-initiated oxidation of α-pinene in the presence of nitrogen oxides (NOx) resulted in the formation of highly oxidized carboxylic acids, such as 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA) and diaterpenylic acid acetate (DTAA). The formation of dimer esters was observed only in SOA produced from the ozonolysis of α-pinene in the absence of NOx, with increased concentrations by a~factor of two at higher RH (50-90%) relative to lower RH (30-50%). The increased formation of dimer esters correlates with an observed increase in new particle formation at higher RH due to nucleation. Increased aerosol acidity was found to have a negligible effect on the formation of the dimer esters. SOA mass yield did not influence the chemical composition of SOA formed from �

Photoelectron spectroscopy of a series of acetate and propionate esters

NASA Astrophysics Data System (ADS)

Śmiałek, Małgorzata A.; Guthmuller, Julien; MacDonald, Michael A.; Zuin, Lucia; Delwiche, Jacques; Hubin-Franskin, Marie-Jeanne; Lesniewski, Tadeusz; Mason, Nigel J.; Limão-Vieira, Paulo

2017-10-01

The electronic state and photoionization spectroscopy of a series of acetate esters: methyl acetate, isopropyl acetate, butyl acetate and pentyl acetate as well as two propionates: methyl propionate and ethyl propionate, have been determined using vacuum-ultraviolet photoelectron spectroscopy. These experimental investigations are complemented by ab initio calculations. The measured first adiabatic and vertical ionization energies were determined as: 10.21 and 10.45 eV for methyl acetate, 9.99 and 10.22 eV for isopropyl acetate, 10.07 and 10.26 eV for butyl acetate, 10.01 and 10.22 eV for pentyl acetate, 10.16 and 10.36 eV for methyl propionate and 9.99 and 10.18 eV for ethyl propionate. For the four smaller esters vibrational transitions were calculated and compared with those identified in the photoelectron spectrum, revealing the most distinctive ones to be a Csbnd O stretch combined with a Cdbnd O stretch. The ionization energies of methyl and ethyl esters as well as for a series of formates and acetates were compared showing a clear dependence of the value of the ionization energy on the size of the molecule with very little influence of its conformation.

An extractive membrane biofilm reactor as alternative technology for the treatment of methyl tert-butyl ether contaminated water.

PubMed

Guisado, I M; Purswani, J; González-López, J; Pozo, C

2016-09-01

Among the strategies developed for contaminated groundwater bioremediation, those based on the use of bacteria adhering to inert supports and establishing biofilms have gained great importance in this field. Extractive membrane biofilm reactor (EMBFR) technology offers productive solutions for the removal of volatile and semi-volatile compounds. EMBFR technology is based on the use of extractive semipermeable membranes through which contaminants migrate to the biological compartment in which microorganisms with pollutant biotransformation and/or mineralization capacities can grow, forming an active biofilm on the membrane surface. The objective of this study was to assess the use of three bacterial strains (Paenibacillus sp. SH7 CECT 8558, Agrobacterium sp. MS2 CECT 8557, and Rhodococcus ruber EE6 CECT 8612), as inoculum in a lab-scale EMBFR running for 28 days under aerobic conditions to eliminate methyl tert-butyl ether (MTBE) from water samples. Three different hydraulic retention times (1, 6, and 12 h) were employed. MTBE degradation values were determined daily by a gas GC-MS technique, as well as suspended bacterial growth. The biofilm established by the bacterial strains on the semipermeable membrane was detected by Field-Emission Scanning Electron Microscopy (FESEM) at the end of each experiment. The acute toxicity of the treated effluents and biomedium was determined by Microtox © assay (EC 50 ).The results achieved from the MTBE degradation, biofilm formation, and toxicity analysis indicated that bacterial strains MS2 and EE6 were the best options as selective inoculum, although further research is needed, particularly with regard to their possible use as a mixed culture. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1238-1245, 2016. © 2016 American Institute of Chemical Engineers.

Changes of lipid and fatty acid absorption induced by high dose of citric acid ester and lecithin emulsifiers.

PubMed

Sadouki, Mohamed; Bouchoucha, Michel

2014-09-01

To describe the effect of two food emulsifiers, lecithin (E322) and citric acid esters of mono-and diglycerides of fatty acids (E472c), on the intestinal absorption of lipids. The experiment was conducted on 24 male Wistar rats randomly assigned in three groups. For two groups of six rats, 30% of the lipid intake was replaced with lecithin (L) or citric acid ester of mono and diglycerides, (E); the remaining 12 rats were the control group (C). Diet and fecal fat analysis was used to determine the apparent lipid absorption (ALA) and fatty acids. ALA was significantly lower in the group E than in the groups C and L (p < 0.001). ALA of long saturated chain fatty acids decreased while the length of the carbon chains increased, and this decrease was higher in the group E. E472c emulsifier decreased the intestinal absorption of lipids.

Process for the generation of .alpha., .beta.-unsaturated carboxylic acids and esters using niobium catalyst

DOEpatents

Gogate, Makarand Ratnakav; Spivey, James Jerome; Zoeller, Joseph Robert

1999-01-01

A process using a niobium catalyst includes the step of reacting an ester or carboxylic acid with oxygen and an alcohol in the presence a niobium catalyst to respectively produce an .alpha.,.beta.-unsaturated ester or carboxylic acid. Methanol may be used as the alcohol, and the ester or carboxylic acid may be passed over the niobium catalyst in a vapor stream containing oxygen and methanol. Alternatively, the process using a niobium catalyst may involve the step of reacting an ester and oxygen in the presence the niobium catalyst to produce an .alpha.,.beta.-unsaturated carboxylic acid. In this case the ester may be a methyl ester. In either case, niobium oxide may be used as the niobium catalyst with the niobium oxide being present on a support. The support may be an oxide selected from the group consisting of silicon oxide, aluminum oxide, titanium oxide and mixtures thereof. The catalyst may be formed by reacting niobium fluoride with the oxide serving as the support. The niobium catalyst may contain elemental niobium within the range of 1 wt % to 70 wt %, and more preferably within the range of 10 wt % to 30 wt %. The process may be operated at a temperature from 150 to 450.degree. C. and preferably from 250 to 350.degree. C. The process may be operated at a pressure from 0.1 to 15 atm. absolute and preferably from 0.5-5 atm. absolute. The flow rate of reactants may be from 10 to 10,000 L/kg.sub.(cat) /h, and preferably from 100 to 1,000 L/kg.sub.(cat) /h.

Palladium-Catalyzed α-Arylation of Zinc Enolates of Esters: Reaction Conditions and Substrate Scope

PubMed Central

Hama, Takuo; Ge, Shaozhong; Hartwig, John F.

2013-01-01

The intermolecular α-arylation of esters by palladium-catalyzed coupling of aryl bromides with zinc enolates of esters is reported. Reactions of three different types of zinc enolates have been developed. α-Arylation of esters occurs in high yields with isolated Reformatsky reagents, with Reformatsky reagents generated from α-bromo esters and activated zinc, and with zinc enolates generated by quenching lithium enolates of esters with zinc chloride. The use of zinc enolates, instead of alkali metal enolates, greatly expands the scope of the arylation of esters. The reactions occur at room temperature or at 70 °C with bromoarenes containing cyano, nitro, ester, keto, fluoro, enolizable hydrogen, hydroxyl or amino functionality and with bromopyridines. The scope of esters encompasses acyclic acetates, propionates, and isobutyrates, α-alkoxyesters, and lactones. The arylation of zinc enolates of esters was conducted with catalysts bearing the hindered pentaphenylferrocenyl di-tert-butylphosphine (Q-phos) or the highly reactive dimeric Pd(I) complex {[P(t-Bu)3]PdBr}2. PMID:23931445

40 CFR 721.10300 - Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester. 721.10300 Section 721.10300 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.10300 Benzeneacetic acid, .alpha.-chloro-.alpha...

40 CFR 721.10300 - Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester. 721.10300 Section 721.10300 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.10300 Benzeneacetic acid, .alpha.-chloro-.alpha...

40 CFR 721.10300 - Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzeneacetic acid, .alpha.-chloro-.alpha.-phenyl-, ethyl ester. 721.10300 Section 721.10300 Protection of Environment ENVIRONMENTAL... Significant New Uses for Specific Chemical Substances § 721.10300 Benzeneacetic acid, .alpha.-chloro-.alpha...

Selective coupling of methotrexate to peptide hormone carriers through a gamma-carboxamide linkage of its glutamic acid moiety: benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate activation in salt coupling.

PubMed Central

Nagy, A; Szoke, B; Schally, A V

1993-01-01

A convenient synthetic method is described for the preparation of peptide-methotrexate (MTX) conjugates in which MTX is coupled selectively through the gamma-carboxyl group of its glutamic acid moiety to a free amino group in peptide analogs. The syntheses of a somatostatin analog-MTX conjugate (MTX-D-Phe-Cys-Tyr-D-Trp-Lys-Val-Cys-Thr-NH2) (AN-51) and two conjugates of analogs of luteinizing hormone-releasing hormone (LH-RH) with MTX [Glp-His-Trp-Ser-Tyr-D-Lys(MTX)-Leu-Arg-Pro-Gly-NH2] (AJ-04) and [Ac-Ser-Tyr-D-Lys(MTX)-Leu-Arg-Pro-NH-Et] AJ-51 are presented as examples. Benzotriazol-1-yloxytris(dimethylamino)phosphonium hexafluorophosphate (BOP reagent) was used in the synthesis for activation of 4-amino-4-deoxy-N10-methylpteroic acid, which reacted with the potassium salt of glutamic acid alpha-tert-butyl ester in dimethyl sulfoxide to form the suitably protected MTX derivative. This synthesis provides an example of the high suitability of BOP reagent for the salt-coupling method. The selectively protected MTX derivative was then coupled to the different peptide carriers and deprotected under relatively mild conditions by trifluoroacetic acid. The conjugates of MTX with hormonal analogs are suitable for targeting to various tumors that possess receptors for the peptide moieties. PMID:8101004

Determination of selected fatty acids in dried sweat spot using gas chromatography with flame ionization detection.

PubMed

Kanďár, Roman; Drábková, Petra; Andrlová, Lenka; Kostelník, Adam; Čegan, Alexander

2016-11-01

A method is described for the determination of fatty acids in dried sweat spot and plasma samples using gas chromatography with flame ionization detection. Plasma and dried sweat spot samples were obtained from a group of blood donors. The sweat was collected from each volunteer during exercise. Sweat was spotted onto collection paper containing butylated hydroxytoluene. Fatty acids were derivatized with acetyl chloride in methanol to form methyl esters of fatty acids. The fatty acids in dried sweat spot samples treated with butylated hydroxytoluene and stored at -20°C were stable for 3 months. Our results indicate that sweat contains, among fatty acids with short chain, also fatty acids with long chain and unsaturated fatty acids. Linear relationships between percentage content of selected fatty acids in dried sweat spot and plasma were observed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The use of fatty acid esters to enhance free acid sophorolipid synthesis.

PubMed

Ashby, Richard D; Solaiman, Daniel K Y; Foglia, Thomas A

2006-02-01

Fatty acid esters were prepared by transesterification of soy oil with methanol (methyl-soyate, Me-Soy), ethanol (ethyl-soyate, Et-Soy) and propanol (propyl-soyate, Pro-Soy) and used with glycerol as fermentation substrates to enhance production of free-acid sophorolipids (SLs). Fed-batch fermentations of Candida bombicola resulted in SL yields of 46 +/- 4 g/l, 42 +/- 7 g/l and 18 +/- 6 g/l from Me-Soy, Et-Soy, and Pro-Soy, respectively. Liquid chromatography with atmospheric pressure ionization mass spectrometry (LC/API-MS) showed that Me-Soy resulted in 71% open-chain SLs with 59% of those molecules remaining esterified at the carboxyl end of the fatty acids. Et-Soy and Pro-Soy resulted in 43% and 80% open-chain free-acid SLs, respectively (containing linoleic acid and oleic acid as the principal fatty acid species linked to the sophorose sugar at the omega-1 position), with no evidence of residual esterification.

Final report of the safety assessment of methacrylate ester monomers used in nail enhancement products.

PubMed

2005-01-01

Methacrylate ester monomers are used in as artificial nail builders in nail enhancement products. They undergo rapid polymerization to form a hard material on the nail that is then shaped. While Ethyl Methacrylate is the primary monomer used in nail enhancement products, other methacrylate esters are also used. This safety assessment addresses 22 other methacrylate esters reported by industry to be present in small percentages as artificial nail builders in cosmetic products. They function to speed up polymerization and/or form cross-links. Only Tetrahydrofurfuryl Methacrylate was reported to the FDA to be in current use. The polymerization rates of these methacrylate esters are within the same range as Ethyl Methacrylate. While data are not available on all of these methacrylate esters, the available data demonstrated little acute oral, dermal, or i.p. toxicity. In a 28-day inhalation study on rats, Butyl Methacrylate caused upper airway irritation; the NOAEL was 1801 mg/m3. In a 28-day oral toxicity study on rats, t-Butyl Methacrylate had a NOAEL of 20 mg/kg/day. Beagle dogs dosed with 0.2 to 2.0 g/kg/day of C12 to C18 methacrylate monomers for 13 weeks exhibited effects only in the highest dose group: weight loss, emesis, diarrhea, mucoid feces, or salivation were observed. Butyl Methacrylate (0.1 M) and Isobutyl Methacrylate (0.1 M) are mildly irritating to the rabbit eye. HEMA is corrosive when instilled in the rabbit eye, while PEG-4 Dimethacrylate and Trimethylolpropane Trimethacrylate are minimally irritating to the eye. Dermal irritation caused by methacrylates is documented in guinea pigs and rabbits. In guinea pigs, HEMA, Isopropylidenediphenyl Bisglycidyl Methacrylate, Lauryl Methacrylate, and Trimethylolpropane Trimethacrylate are strong sensitizers; Butyl Methacrylate, Cyclohexyl Methacrylate, Hexyl Methacrylate, and Urethane Methacrylate are moderate sensitizers; Hydroxypropyl Methacrylate is a weak sensitizer; and PEG-4 Dimethacrylate and

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Boric acid (H3BO3), mixed esters with... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Boric acid (H3BO3), mixed esters with... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid (H3BO3), mixed esters with... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Boric acid (H3BO3), mixed esters with... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

40 CFR 721.1729 - Boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Boric acid (H3BO3), mixed esters with... acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol mono Me ether... identified as boric acid (H3BO3), mixed esters with polyethylene glycol mono-Bu ether and polyethylene glycol...

[Development of the determination methods of fatty acid esters of chloropropanediols in fat-rich foods].

PubMed

Yan, Xiaobo; Wu, Shaoming; Li, Nan; Lü, Huadong; Fu, Wusheng

2013-02-01

Fatty acid esters of chloropropanediols are a kinds of newly emerged food contaminants, especially 3-monochloropropane-1,2-diol (3-MCPD) esters that have been detected in many foodstuffs such as infant formula and edible oils at relatively high levels. Based on the Tolerable Dose Intake (TDI) of 3-MCPD, the intake of 3-MCPD from 3-MCPD esters may cause the health risk to human beings. The researches for the analysis of 3-MCPD esters have been carried out in some institutes abroad, but there were only a few in China. This paper reviews the methods for the determination of 3-MCPD esters in fat-rich foods, including the extraction, hydrolysis, the derivatization of 3-MCPD esters, the total amount of 3-MCPD esters and the amounts of monoesters and diesters of 3-MCPD.

FT-IR and Raman vibrational analysis, B3LYP and M06-2X simulations of 4-bromomethyl-6-tert-butyl-2H-chromen-2-one

NASA Astrophysics Data System (ADS)

Sert, Yusuf; Puttaraju, K. B.; Keskinoğlu, Sema; Shivashankar, K.; Ucun, Fatih

2015-01-01

In this study, the experimental and theoretical vibrational frequencies of a newly synthesized bacteriostatic and anti-tumor molecule namely, 4-bromomethyl-6-tert-butyl-2H-chromen-2-one have been investigated. The experimental FT-IR (4000-400 cm-1) and Raman spectra (4000-100 cm-1) of the compound in solid phase have been recorded. The theoretical vibrational frequencies and optimized geometric parameters have been calculated using density functional theory (DFT/B3LYP: Becke, 3-parameter, Lee-Yang-Parr and DFT/M06-2X: highly parametrized, empirical exchange correlation function) with 6-311++G(d, p) basis set by Gaussian 03 software, for the first time. The assignments of the vibrational frequencies have been done by potential energy distribution (PED) analysis using VEDA 4 software. The theoretical optimized geometric parameters and vibrational frequencies have been found to be in good agreement with the corresponding experimental data and results in the literature. In addition, the highest occupied molecular orbital (HOMO) energy, the lowest unoccupied molecular orbital (LUMO) energy and the other related molecular energy values of the compound have been investigated using the same theoretical calculations.

Crystal structure of (2-{[(8-aminona-phthalen-1-yl)imino]-meth-yl}-4,6-di-tert-butyl-phenolato-κ3N,N',O)bromido-nickel(II).

PubMed

O'Brien, Patrick; Zeller, Matthias; Lee, Wei-Tsung

2018-04-01

The title compound, [NiBr(C 25 H 29 N 2 O)], contains an Ni II atom with a slightly distorted square-planar coordination environment defined by one O and two N atoms from the 2-{[(8-aminona-phthalen-1-yl)imino]-meth-yl}-4,6-di- tert -butyl-phenolate ligand and a bromide anion. The Ni-O and Ni-N bond lengths are slightly longer than those observed in the phenyl backbone counterpart, which can be attributed to the larger steric hindrance of the naphthyl group in the structure of the title compound. The mol-ecule as a whole is substanti-ally distorted, with both the planar naphthalene-1,8-di-amine and imino-meth-yl-phenolate substitutents rotated against the NiN 2 OBr plane by 38.92 (7) and 37.22 (8)°, respectively, giving the mol-ecule a twisted appearance. N-H⋯Br hydrogen bonds and N-H⋯C(π) contacts connect the mol-ecules into dimers, and additional C-H⋯Br contacts, C-H⋯π inter-actions, and an offset stacking inter-action between naphthyl units inter-connect these dimers into a three-dimensional network.

Discovery, Synthesis, And Structure-Based Optimization of a Series of N-(tert-Butyl)-2-(N-arylamido)-2-(pyridin-3-yl) Acetamides (ML188) as Potent Noncovalent Small Molecule Inhibitors of the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) 3CL Protease

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

Jacobs, Jon; Grum-Tokars, Valerie; Zhou, Ya

A high-throughput screen of the NIH molecular libraries sample collection and subsequent optimization of a lead dipeptide-like series of severe acute respiratory syndrome (SARS) main protease (3CLpro) inhibitors led to the identification of probe compound ML188 (16-(R), (R)-N-(4-(tert-butyl)phenyl)-N-(2-(tert-butylamino)-2-oxo-1-(pyridin-3-yl)ethyl)furan-2-carboxamide, Pubchem CID: 46897844). But, unlike the majority of reported coronavirus 3CLpro inhibitors that act via covalent modification of the enzyme, 16-(R) is a noncovalent SARS-CoV 3CLpro inhibitor with moderate MW and good enzyme and antiviral inhibitory activity. A multicomponent Ugi reaction was utilized to rapidly explore structure–activity relationships within S1', S1, and S2enzyme binding pockets. Moreover, the X-ray structure of SARS-CoV 3CLpromore » bound with 16-(R) was instrumental in guiding subsequent rounds of chemistry optimization. 16-(R) provides an excellent starting point for the further design and refinement of 3CLpro inhibitors that act by a noncovalent mechanism of action.« less

Dramatic Influence of Ionic Liquid and Ultrasound Irradiation on the Electrophilic Sulfinylation of Aromatic Compounds by Sulfinic Esters.

PubMed

Nguyen, Ngoc-Lan Thi; Vo, Hong-Thom; Duus, Fritz; Luu, Thi Xuan Thi

2017-09-04

The sulfinylation reaction of aromatic and hetero-aromatic compounds with sulfinic esters as electrophiles has been investigated in different ionic liquids and by means of different Lewis acid salts in order to get moderate to good yields of asymmetrical sulfoxides. Mixtures of 1-butyl-3-methylimidazolium chloride and aluminum chloride were found to be the most efficient and recyclable reaction framework. Ultrasound sonication appeared to be the most useful and green activation method to afford the sulfoxides in yields better than or equivalent to those obtained under the longer-lasting conventional stirring conditions.

21 CFR 172.225 - Methyl and ethyl esters of fatty acids produced from edible fats and oils.

Code of Federal Regulations, 2014 CFR

2014-04-01

... from edible fats and oils. 172.225 Section 172.225 Food and Drugs FOOD AND DRUG ADMINISTRATION... acids produced from edible fats and oils. Methyl esters and ethyl esters of fatty acids produced from edible fats and oils may be safely used in food, subject to the following prescribed conditions: (a) The...

Exposure to methyl tert-butyl ether, benzene, and total hydrocarbons at the Singapore-Malaysia causeway immigration checkpoint

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

Tan, C.; Ong, H.Y.; Kok, P.W.

1996-12-31

The primary aim of this study was to determine the extent and levels of exposure to volatile organic compounds (VOCs) from automobile emissions in a group of immigration officers at a busy cross-border checkpoint. A majority (80%) of the workers monitored were exposed to benzene at levels between 0.01 and 0.5 ppm, with only 1.2% exceeding the current Occupational Safety and Health Administration occupational exposure limit of 1 ppm. The geometric mean (GM) concentrations of 8-hr time-weighted average exposure were 0.03 ppm, 0.9 ppm, and 2.46 ppm for methyl-tert-butyl ether (MTBE), benzene, and total hydrocarbons (THC), respectively. The highest time-weightedmore » average concentrations measured were 1.05 ppm for MTBE, 2.01 ppm for benzene, and 34 ppm for THC. It was found that motorbikes emitted a more significant amount of pollutants compared with motor cars. On average, officers at the motorcycle booths were exposed to four to five times higher levels of VOCs (GMs of 0.07 ppm, 0.23 ppm, and 4.7 ppm for MTBE, benzene, and THC) than their counterparts at the motor car booths (GMs of 0.01 ppm, 0.05 ppm, and 1.5 ppm). The airborne concentrations of all three pollutants correlated with the flow of vehicle traffic. Close correlations were also noted for the concentrations in ambient air for the three pollutants measured. Benzene and MTBE had a correlation coefficient of 0.97. The overall findings showed that the concentrations of various VOCs were closely related to the traffic density, suggesting that they were from a common source, such as exhaust emissions from the vehicles. The results also indicated that although benzene, MTBE, and THC are known to be volatile, a significant amount could still be detected in the ambient environment, thus contributing to our exposure to these compounds. 4 refs., 6 figs.« less

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

40 CFR 721.1875 - Boric acid, alkyl and substituted alkyl esters (generic name).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Boric acid, alkyl and substituted... Significant New Uses for Specific Chemical Substances § 721.1875 Boric acid, alkyl and substituted alkyl... chemical substance boric acid, alkyl and substituted alkyl esters (PMN P-86-1252) is subject to reporting...

Assessment of the hydrolysis process for the determination of okadaic acid-group toxin ester: presence of okadaic acid 7-O-acyl-ester derivates in Spanish shellfish.

PubMed

Villar-González, A; Rodríguez-Velasco, M L; Ben-Gigirey, B; Yasumoto, T; Botana, L M

2008-04-01

The contamination of different types of shellfish by okadaic acid (OA)-group toxin esters is an important problem that presents serious risk for human health. During previous investigations carried out in our laboratory by liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS), the occurrence of a high percentage of esters in relation to the total OA equivalents has been observed in several shellfish species. The determination of these kinds of toxins using LC/MS or other chemical methods requires a hydrolysis step in order to convert the sterified compounds into the parent toxins, OA, dinophysistoxins-1 (DTX-1) and dinophysistoxins-2 (DTX-2). Most of the hydrolysis procedures are based on an alkaline hydrolysis reaction. However, despite hydrolysis being a critical step within the analysis, it has not been studied in depth up to now. The present paper reports the results obtained after evaluating the hydrolysis process of an esterified form of OA by using a standard of 7-O-acyl ester with palmitoyl as the fatty acid (palOA). Investigations were focused on checking the effectiveness of the hydrolysis for palOA using methanol as solvent standard and matrices matched standards. From the results obtained, no matrix influence on the hydrolysis process was observed and the quantity of palOA converted into OA was always above 80%. The analyses of different Spanish shellfish samples showed percentages of palOA in relation to the total OA esters ranging from 27% to 90%, depending on the shellfish specie.

40 CFR 721.9965 - Fatty acids, C10-13 - branched, vinyl esters.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Fatty acids, C10-13 - branched, vinyl... Specific Chemical Substances § 721.9965 Fatty acids, C10-13 - branched, vinyl esters. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as fatty...

40 CFR 721.9965 - Fatty acids, C10-13 - branched, vinyl esters.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Fatty acids, C10-13 - branched, vinyl... Specific Chemical Substances § 721.9965 Fatty acids, C10-13 - branched, vinyl esters. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as fatty...

21 CFR 178.3450 - Esters of stearic and palmitic acids.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND...

21 CFR 178.3450 - Esters of stearic and palmitic acids.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Esters of stearic and palmitic acids. 178.3450 Section 178.3450 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: ADJUVANTS, PRODUCTION AIDS, AND...

Development and application of a rat PBPK model to elucidate kidney and liver effects induced by ETBE and tert-butanol.

PubMed

Salazar, Keith D; Brinkerhoff, Christopher J; Lee, Janice S; Chiu, Weihsueh A

2015-11-01

Subchronic and chronic studies in rats of the gasoline oxygenates ethyl tert-butyl ether (ETBE) and tert-butanol (TBA) report similar noncancer kidney and liver effects but differing results with respect to kidney and liver tumors. Because TBA is a major metabolite of ETBE, it is possible that TBA is the active toxic moiety in all these studies, with reported differences due simply to differences in the internal dose. To test this hypothesis, a physiologically-based pharmacokinetic (PBPK) model was developed for ETBE and TBA to calculate internal dosimetrics of TBA following either TBA or ETBE exposure. This model, based on earlier PBPK models of methyl tert-butyl ether (MTBE), was used to evaluate whether kidney and liver effects are consistent across routes of exposure, as well as between ETBE and TBA studies, on the basis of estimated internal dose. The results demonstrate that noncancer kidney effects, including kidney weight changes, urothelial hyperplasia, and chronic progressive nephropathy (CPN), yielded consistent dose-response relationships across routes of exposure and across ETBE and TBA studies using TBA blood concentration as the dose metric. Relative liver weights were also consistent across studies on the basis of TBA metabolism, which is proportional to TBA liver concentrations. However, kidney and liver tumors were not consistent using any dose metric. These results support the hypothesis that TBA mediates the noncancer kidney and liver effects following ETBE administration; however, additional factors besides internal dose are necessary to explain the induction of liver and kidney tumors. Published by Elsevier Inc.

A nonaqueous potentiometric titration study of the dissociation of t-butyl methacrylate-methacrylic acid copolymers.

PubMed

Nakatani, Kiyoharu; Yamashita, Jun; Sekine, Tomomi; Toriumi, Minoru; Itani, Toshiro

2003-05-01

The dissociation of t-butyl methacrylate-methacrylic acid copolymers in dimethyl sulfoxide was analyzed by a nonaqueous potentiometric titration technique. The negative logarithm of the dissociation constant of the monomer unit of a methacrylic acid (MAA) monotonously increased with the increasing degree of dissociation corresponding to the titrant/MAA amount ratio, and was highly influenced by the copolymerization ratio. The results are discussed in terms of the suppression of the dissociation of MAA by a neighboring charged methacrylate anion unit.

SIRT1 exhibits antioxidative effects in HT22 cells induced by tert-butyl alcohol.

PubMed

Ma, Junxiang; Song, Dongmei; Zhang, Yuanyuan; Chen, Li; Zhang, Shixuan; Jia, Jiaxin; Chen, Tian; Guo, Caixia; Tian, Lin; Gao, Ai; Niu, Piye

2018-02-01

Tertiary butyl alcohol (TBA) is a principal metabolite of methyl tertiary-butyl ether (MTBE), a common pollutant worldwide in the ground or underground water, which is found to produce nervous system damage. Nevertheless, few data regarding the effects of TBA has been reported. Studies indicated that oxidative stress plays a pivotal role in MTBE neurotoxic mechanism. Sirtuin 1 (SIRT1) has been reported to exert a neuroprotective effect on various neurologic diseases via resistance to oxidative stress by deacetylating its substrates. In this study, we examined levels of oxidative stress after exposure to TBA for 6 h in HT22 cells and HT22 cells with SIRT1 silencing (transfected with SIRT1 siRNA) or high expression (preconditioned with agonists SRT1720). We found that TBA activated oxidative stress by increasing generation of intracellular reactive oxygen species (ROS), malondialdehyde (MDA) and Oxidized glutathione (GSSG), and decreasing contents of superoxide dismutase (SOD) and glutathione reductase (GSH). In additional, levels of TBA-induced oxidative stress were aggravated when SIRT1 silenced but alleviated when SIRT1 enhanced. Our study indicated that SIRT1 mitigated oxidative stress induced by TBA. © 2017 Wiley Periodicals, Inc.

40 CFR 721.10369 - Carbonic acid, diphenyl ester, polymer with diphenyl P-methylphosphonate and 4,4′-(1...

Code of Federal Regulations, 2014 CFR

2014-07-01

... with diphenyl P-methylphosphonate and 4,4â²-(1-methylethylidene) bis[phenol]. 721.10369 Section 721... Carbonic acid, diphenyl ester, polymer with diphenyl P-methylphosphonate and 4,4′-(1-methylethylidene) bis... identified as carbonic acid, diphenyl ester, polymer with diphenyl P-methylphosphonate and 4,4′-(1...

Phthalic acid esters in soils from vegetable greenhouses in Shandong Peninsula, East China.

PubMed

Chai, Chao; Cheng, Hongzhen; Ge, Wei; Ma, Dong; Shi, Yanxi

2014-01-01

Soils at depths of 0 cm to 10 cm, 10 cm to 20 cm, and 20 cm to 40 cm from 37 vegetable greenhouses in Shandong Peninsula, East China, were collected, and 16 phthalic acid esters (PAEs) were detected using gas chromatography-mass spectrometry (GC-MS). All 16 PAEs could be detected in soils from vegetable greenhouses. The total of 16 PAEs (Σ16PAEs) ranged from 1.939 mg/kg to 35.442 mg/kg, with an average of 6.748 mg/kg. Among four areas, including Qingdao, Weihai, Weifang, and Yantai, the average and maximum concentrations of Σ16PAEs in soils at depths of 0 cm to 10 cm appeared in Weifang, which has a long history of vegetable production and is famous for extensive greenhouse cultivation. Despite the different concentrations of Σ16PAEs, the PAE compositions were comparable. Among the 16 PAEs, di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) were the most abundant. Compared with the results on agricultural soils in China, soils that are being used or were used for vegetable greenhouses had higher PAE concentrations. Among PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP) and DnBP exceeded soil allowable concentrations (in US) in more than 90% of the samples, and DnOP in more than 20%. Shandong Peninsula has the highest PAE contents, which suggests that this area is severely contaminated by PAEs.

Phthalic Acid Esters in Soils from Vegetable Greenhouses in Shandong Peninsula, East China

PubMed Central

Chai, Chao; Cheng, Hongzhen; Ge, Wei; Ma, Dong; Shi, Yanxi

2014-01-01

Soils at depths of 0 cm to 10 cm, 10 cm to 20 cm, and 20 cm to 40 cm from 37 vegetable greenhouses in Shandong Peninsula, East China, were collected, and 16 phthalic acid esters (PAEs) were detected using gas chromatography-mass spectrometry (GC-MS). All 16 PAEs could be detected in soils from vegetable greenhouses. The total of 16 PAEs (Σ16PAEs) ranged from 1.939 mg/kg to 35.442 mg/kg, with an average of 6.748 mg/kg. Among four areas, including Qingdao, Weihai, Weifang, and Yantai, the average and maximum concentrations of Σ16PAEs in soils at depths of 0 cm to 10 cm appeared in Weifang, which has a long history of vegetable production and is famous for extensive greenhouse cultivation. Despite the different concentrations of Σ16PAEs, the PAE compositions were comparable. Among the 16 PAEs, di(2-ethylhexyl) phthalate (DEHP), di-n-octyl phthalate (DnOP), di-n-butyl phthalate (DnBP), and diisobutyl phthalate (DiBP) were the most abundant. Compared with the results on agricultural soils in China, soils that are being used or were used for vegetable greenhouses had higher PAE concentrations. Among PAEs, dimethyl phthalate (DMP), diethyl phthalate (DEP) and DnBP exceeded soil allowable concentrations (in US) in more than 90% of the samples, and DnOP in more than 20%. Shandong Peninsula has the highest PAE contents, which suggests that this area is severely contaminated by PAEs. PMID:24747982

Alternative fuel properties of tall oil fatty acid methyl ester-diesel fuel blends.

PubMed

Altiparmak, Duran; Keskin, Ali; Koca, Atilla; Gürü, Metin

2007-01-01

In this experimental work, tall oil methyl ester-diesel fuel blends as alternative fuels for diesel engines were studied. Tall oil methyl ester was produced by reacting tall oil fatty acids with methyl alcohol under optimum conditions. The blends of tall oil methyl ester-diesel fuel were tested in a direct injection diesel engine at full load condition. The effects of the new fuel blends on the engine performance and exhaust emission were tested. It was observed that the engine torque and power output with tall oil methyl ester-diesel fuel blends increased up to 6.1% and 5.9%, respectively. It was also seen that CO emissions decreased to 38.9% and NO(x) emissions increased up to 30% with the new fuel blends. The smoke opacity did not vary significantly.

Substituted Caffeic and Ferulic Acid Phenethyl Esters: Synthesis, Leukotrienes Biosynthesis Inhibition, and Cytotoxic Activity.

PubMed

Morin, Pier; St-Coeur, Patrick-Denis; Doiron, Jérémie A; Cormier, Marc; Poitras, Julie J; Surette, Marc E; Touaibia, Mohamed

2017-07-06

Glioblastoma multiforme (GBM) is an aggressive brain tumor that correlates with short patient survival and for which therapeutic options are limited. Polyphenolic compounds, including caffeic acid phenethyl ester (CAPE, 1a ), have been investigated for their anticancer properties in several types of cancer. To further explore these properties in brain cancer cells, a series of caffeic and ferulic acid esters bearing additional oxygens moieties (OH or OCH₃) were designed and synthesized. (CAPE, 1a ), but not ferulic acid phenethyl ester (FAPE, 1b ), displayed substantial cytotoxicity against two glioma cell lines. Some but not all selected compounds derived from both (CAPE, 1a ) and (FAPE, 1b ) also displayed cytotoxicity. All CAPE-derived compounds were able to significantly inhibit 5-lipoxygenase (5-LO), however FAPE-derived compounds were largely ineffective 5-LO inhibitors. Molecular docking revealed new hydrogen bonds and π-π interactions between the enzyme and some of the investigated compounds. Overall, this work highlights the relevance of exploring polyphenolic compounds in cancer models and provides additional leads in the development of novel therapeutic strategies in gliomas.

Isolation of tert-alkylphenols from the products of alkylation of phenols

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

Nesterova, T.N.; Verevkin, S.P.; Rempel', R.D.

1987-08-10

The authors studied the conditions of isolation of tert-amyl-, hexyl-, heptyl-, octyl-, decyl-, and dodecylphenols, and tert-alkylcresols, alkylpyrocatechols, and alkylhydroquinones from alkylation products. The compounds were isolated in all cases from reaction mixtures obtained in presence of cation-exchange resins of the KU-2 type. A preliminary stage, flash evaporation of the reaction mass at 4-13 Pa for 5-15 min, is needed to prevent decomposition of tert-alkylphenols during their isolation from acid reaction mixtures by fractionation. Flash distillation of high-boiling tert-alkylphenols should be conducted in presence of a component lowering the boiling point of the mixture, added in 1:(0.5-1.0) weight ratio ofmore » original mixture to the component.« less

21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

Code of Federal Regulations, 2014 CFR

2014-04-01

... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. (a) Product. Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or...

21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

Code of Federal Regulations, 2013 CFR

2013-04-01

... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. (a) Product. Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or...

21 CFR 582.4101 - Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat...

Code of Federal Regulations, 2012 CFR

2012-04-01

... diglycerides of edible fats or oils, or edible fat-forming fatty acids. 582.4101 Section 582.4101 Food and... Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or edible fat-forming fatty acids. (a) Product. Diacetyl tartaric acid esters of mono- and diglycerides of edible fats or oils, or...

21 CFR 178.3780 - Polyhydric alcohol esters of long chain monobasic acids.

Code of Federal Regulations, 2014 CFR

2014-04-01

... § 177.1980 of this chapter that contact food of Types I, II, IV-B, VI-B, VII-B, and VIII identified in... produced by the reaction of either ethylene glycol or glycerol with long chain monobasic acids containing... carboxylic acids in the formation of the glycerol esters being neutralized with calcium hydroxide to produce...

Microfluidic White Organic Light-Emitting Diode Based on Integrated Patterns of Greenish-Blue and Yellow Solvent-Free Liquid Emitters

NASA Astrophysics Data System (ADS)

Kobayashi, Naofumi; Kasahara, Takashi; Edura, Tomohiko; Oshima, Juro; Ishimatsu, Ryoichi; Tsuwaki, Miho; Imato, Toshihiko; Shoji, Shuichi; Mizuno, Jun

2015-10-01

We demonstrated a novel microfluidic white organic light-emitting diode (microfluidic WOLED) based on integrated sub-100-μm-wide microchannels. Single-μm-thick SU-8-based microchannels, which were sandwiched between indium tin oxide (ITO) anode and cathode pairs, were fabricated by photolithography and heterogeneous bonding technologies. 1-Pyrenebutyric acid 2-ethylhexyl ester (PLQ) was used as a solvent-free greenish-blue liquid emitter, while 2,8-di-tert-butyl-5,11-bis(4-tert-butylphenyl)-6,12-diphenyltetracene (TBRb)-doped PLQ was applied as a yellow liquid emitter. In order to form the liquid white light-emitting layer, the greenish-blue and yellow liquid emitters were alternately injected into the integrated microchannels. The fabricated electro-microfluidic device successfully exhibited white electroluminescence (EL) emission via simultaneous greenish-blue and yellow emissions under an applied voltage of 100 V. A white emission with Commission Internationale de l’Declairage (CIE) color coordinates of (0.40, 0.42) was also obtained; the emission corresponds to warm-white light. The proposed device has potential applications in subpixels of liquid-based microdisplays and for lighting.

Biodegradation of buprofezin by Rhodococcus sp. strain YL-1 isolated from rice field soil.

PubMed

Li, Chao; Zhang, Ji; Wu, Zhi-Guo; Cao, Li; Yan, Xin; Li, Shun-Peng

2012-03-14

A buprofezin-degrading bacterium, YL-1, was isolated from rice field soil. YL-1 was identified as Rhodococcus sp. on the basis of the comparative analysis of 16S rDNA sequences. The strain could use buprofezin as the sole source of carbon and nitrogen for growth and was able to degrade 92.4% of 50 mg L(-1) buprofezin within 48 h in liquid culture. During the degradation of buprofezin, four possible metabolites, 2-tert-butylimino-3-isopropyl-1,3,5-thiadiazinan-4-one, N-tert-butyl-thioformimidic acid formylaminomethyl ester, 2-isothiocyanato-2-methyl-propane, and 2-isothiocyanato-propane, were identified using gas chromatography-mass spectrometry (GC-MS) analysis. The catechol 2,3-dioxygenase activity was strongly induced during the degradation of buprofezin. A novel microbial biodegradation pathway for buprofezin was proposed on the basis of these metabolites. The inoculation of soils treated with buprofezin with strain YL-1 resulted in a higher degradation rate than that observed in noninoculated soils, indicating that strain YL-1 has the potential to be used in the bioremediation of buprofezin-contaminated environments.

The Role of Chlorogenic Acid Supplementation in Anemia and Mineral Disturbances Induced by 4-Tert-Octylphenol Toxicity.

PubMed

Koriem, Khaled M M; Arbid, Mahmoud S S; Gomaa, Nawal E

2018-01-02

4-tert-octylphenol (OP) is an endocrine-disrupting chemical that causes harmful effects to human health. Chlorogenic acid is the major dietary polyphenol present in various foods and beverages. The aim of the present study was to evaluate the protective role of chlorogenic acid in anemia and mineral disturbance occurring in OP toxicity in rats. Thirty-two male albino rats were divided into four equal groups (8 rats/group) as follows. The first (control) group was treated daily with an oral dose of 1 ml saline for two weeks. The second group was treated daily with an oral dose of 60 mg chlorogenic acid/kg body weight for two weeks. The third and fourth groups received daily intraperitoneal (ip) injections with 100 mg OP/kg body weight for two weeks; the fourth group was treated daily with an oral dose of 60 mg chlorogenic acid/kg body weight for three weeks starting one week before OP injections. The results revealed that OP induced significant decreases in hemoglobin, hematocrit, red blood cells, mean cell volume, mean cell hemoglobin, mean cell hemoglobin concentration, platelet count, white blood cells, lymphocyte and neutrophil percent, transferrin receptor, serum calcium, phosphorous, sodium, potassium, chloride, glutathione-S-transferase, glutathione peroxidase, catalase, glutathione reductase, and superoxide dismutase. Moreover, significant increases in serum hepcidin, ferritin, transferrin, erythropoietin, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, urea, creatinine, selenium, zinc, manganese, copper, iron, malondialdehyde, and protein carbonyl levels were found in OP groups. OP exposure also induced cell apoptosis. Chlorogenic acid pretreatment in OP-treated groups restored all the mentioned parameters to approach the normal values. In conclusion, chlorogenic acid protects from anemia and mineral disturbances in 4-tert-octylphenol toxicity by ameliorating oxidative stress and apoptosis.

Orally administered glycidol and its fatty acid esters as well as 3-MCPD fatty acid esters are metabolized to 3-MCPD in the F344 rat.

PubMed

Onami, Saeko; Cho, Young-Man; Toyoda, Takeshi; Akagi, Jun-ichi; Fujiwara, Satoshi; Ochiai, Ryosuke; Tsujino, Kazushige; Nishikawa, Akiyoshi; Ogawa, Kumiko

2015-12-01

IARC has classified glycidol and 3-monochloropropane-1,2-diol (3-MCPD) as group 2A and 2B, respectively. Their esters are generated in foodstuffs during processing and there are concerns that they may be hydrolyzed to the carcinogenic forms in vivo. Thus, we conducted two studies. In the first, we administered glycidol and 3-MCPD and associated esters (glycidol oleate: GO, glycidol linoleate: GL, 3-MCPD dipalmitate: CDP, 3-MCPD monopalmitate: CMP, 3-MCPD dioleate: CDO) to male F344 rats by single oral gavage. After 30 min, 3-MCPD was detected in serum from all groups. Glycidol was detected in serum from the rats given glycidol or GL and CDP and CDO in serum from rats given these compounds. In the second, we examined if metabolism occurs on simple reaction with rat intestinal contents (gastric, duodenal and cecal contents) from male F344 gpt delta rats. Newly produced 3-MCPD was detected in all gut contents incubated with the three 3-MCPD fatty acid esters and in gastric and duodenal contents incubated with glycidol and in duodenal and cecal contents incubated with GO. Although our observation was performed at 1 time point, the results showed that not only 3-MCPD esters but also glycidol and glycidol esters are metabolized into 3-MCPD in the rat. Copyright © 2015 Elsevier Inc. All rights reserved.