- 2,2,6,6-Tetramethylpiperidinium triflate (TMPT): a highly selective and self-separated catalyst for esterification
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An eco-friendly and readily accessible 2,2,6,6-tetramethylpiperidinium triflate was found as highly-selective and self-separated catalyst for esterification under solvent-free condition. The X-ray crystallography revealed that it formed a ‘hydrophobic wall’ which could effectively eliminate the generated water from the reactive sites. Moreover, it could precipitate from the reaction system with excellent recovery ratio (>99%) and be reused for ten times without any significant loss of activity.
- Gao, Lan,Liu, Taoping,Tao, Xiaochun,Huang, Yongmin
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supporting information
p. 4905 - 4909
(2016/10/24)
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- SO3H and NH2+ functional carbon-based solid acid catalyzed transesterification and biodiesel production
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A SO3H and NH2+ functional carbon-based solid acid was used as a highly active heterogeneous catalyst for the transesterification of various carboxylic methyl esters with alcohols under mild conditions. It also showed high catalytic performance for transesterification of triolein with methanol or isopropanol. Furthermore, it was able to catalyze simultaneous esterification and transesterification of rice oil and butter respectively, the yields of biodiesel obtained were up to 94%, and the catalyst could be easily recovered and reused more than ten times without loss of activity, which indicated the carbon-based solid acid was a potential catalyst for the biodiesel industry.
- Cai, Liangzhen,Meng, Decai,Zhan, Shaoqi,Yang, Xiaoxia,Liu, Taoping,Pu, Huiming,Tao, Xiaochun
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p. 72146 - 72149
(2015/09/08)
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- Immobilization of lipase on biocompatible co-polymer of polyvinyl alcohol and chitosan for synthesis of laurate compounds in supercritical carbon dioxide using response surface methodology
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Biocompatible co-polymer matrix has great importance for enzyme immobilization and subsequent biocatalytic applications to synthesize important organic moieties. Citronellyl laurate is a fatty-acid-ester having pleasant fruity aroma and widely used as/in emulsifier, lubricant in textile, paint or ink-additives, surfactants, perfumery and food-flavouring ingredient. In present study, Burkholderia cepacia lipase (BCL) was immobilized on biodegradable co-polymer of chitosan (CHI) and polyvinyl alcohol (PVA). The synthesized bio-catalyst {PVA:CHI:BCL (6:4:2.5)} was characterized by SEM, TGA, lipase assay and protein-content analysis. This biocatalyst was applied to synthesize citronellyl laurate in supercritical carbon-dioxide (SC-CO2) using response surface methodology with five-factor-three-level Box-Behnken-design to optimize reaction parameters (citronellol: 8.5 mmol; vinyl laurate: 19.87 mmol; biocatalyst: 175.6 mg; temperature: 46.02 °C; pressure: 8.81 MPa) which provided 94 ± 1.52% yield. The protocol is extended to synthesize various important 12 laurate compounds with excellent yield (90-98%) and noteworthy recyclability (upto studied 5 recycles). Interestingly, immobilized PVA/CHI/lipase biocatalyst showed 4-fold higher bio-catalytic activity than free lipase in SC-CO2. Moreover, the biocatalyst activity assessment study showed remarkable activity-stability of immobilized biocatalyst in SC-CO2 media as compared to free enzyme. Thus, present protocol demonstrated potential biocatalytic applications for synthesis of important laurate compounds with excellent recyclability in SC-CO2 as greener biocatalyst and reaction medium.
- Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
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p. 1224 - 1236
(2015/07/08)
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- The carbon material functionalized with NH2+ and SO3H groups catalyzed esterification with high activity and selectivity
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A novel carbon-based solid acid was conveniently prepared by heating a mixture of d-glucose, p-toluenesulfonic acid and diphenylammonium tosylate. Its structure was measured by XRD, FT-IR, XPS, 13C MAS NMR and EA to illustrate that the carbon material has been functionalized with NH2+ and SO3H groups and has a strong "hydrophobic effect". It can be used to catalyze the esterification reaction of carboxylic acids with equimolar amounts of sterically demanding and acid-sensitive alcohols with high reactivity (yield up to 90%) and selectivity (up to 95%) in heptane at 80 °C. It could be easily recovered and reused more than ten times without loss of activity.
- Zhan, Shaoqi,Tao, Xiaochun,Cai, Liangzhen,Liu, Xiaohui,Liu, Taoping
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supporting information
p. 4649 - 4653
(2015/02/19)
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- Biocatalysis in bio-derived solvents: An improved approach for medium optimisation
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An improved multi-parameter approach to the correlation of enzymatic activity and solvent properties is proposed. The development of the correlation facilitated the introduction of renewable solvents in a CALB catalysed synthesis of fatty esters. the Partner Organisations 2014.
- Paggiola, Giulia,Hunt, Andrew J.,McElroy, Con R.,Sherwood, James,Clark, James H.
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supporting information
p. 2107 - 2110
(2014/04/17)
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- CeO2 as a versatile and reusable catalyst for transesterification of esters with alcohols under solvent-free conditions
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CeO2 acted as an efficient and reusable heterogeneous catalyst for transesterification of esters with alcohols under the solvent-free conditions at 160 °C. Among the 11 kinds of metal oxides, CeO2 is the most suitable catalyst in terms of catalytic activity, leaching-resistance and reusability. This catalytic system tolerates various esters and alcohols, and valuable esters such as heteroaromatic esters and benzyl benzoates are produced, demonstrating a practical utility of the system. On the basis of kinetic analysis and in situ IR studies of adsorbed species, a reaction mechanism is proposed, in which proton abstraction of alcohol by a Lewis base site of CeO2 to yield alkoxide species is the rate-limiting step.
- Tamura, Masazumi,Hakim Siddiki,Shimizu, Ken-Ichi
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p. 1641 - 1646
(2013/09/24)
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- Specific enzyme-catalyzed hydrolysis and synthesis in aqueous and organic medium using biocatalysts with lipase activity from Aspergillus niger MYA 135
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In the present study, the specific hydrolytic activity of three biocatalysts such as the constitutive mycelium-bound lipase, the induced mycelium-bound lipase and the lyophilized induced supernatant from A. niger MYA 135 was evaluated in both aqueous and organic media.A direct correlation between activity in water and n-hexane was not observed for the same hydrolytic reaction. The n-hexane/water activity ratio (RO/A) was applied to characterize the activity in organic medium. The three biocatalysts showed RO/A values higher than 1 for hydrolysis of long-chain fatty acid esters, demonstrating a higher specific hydrolytic activity in organic solvent than in water. A different behavior was observed during hydrolysis of middle-chain fatty acid esters, which was higher in aqueous medium (R O/Adw) observed in a reaction mixture containing propanol and p-nitrophenyl laurate. Finally, both p-nitrophenyl caprate (C10) and p-nitrophenyl laurate (C12) were preferentially methanolized by the lyophilized induced supernatant, being this lipase activity the most specific biocatalyst preparation under transesterification conditions. A selectivity-based analysis of each lipase preparation toward transesterification or hydrolysis in organic medium was evaluated as well. Springer Science+Business Media, LLC 2012.
- Romero, Cintia M.,Pera, Licia M.,Loto, Flavia,Baigori, Mario D.
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p. 1361 - 1368
(2013/01/15)
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- Preparation, characterisation and evaluation of brazilian clay-based catalysts for use in esterification reactions
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Natural Brazilian clay-based catalysts were prepared, characterised, and their catalytic activity was assessed in esterification reactions. The natural clays were acid activated as received, without any previous treatment. Both natural and acid-activated clays were characterised by XRD, NH3-TPD, thermodesorption of n-butylamine, N2 adsorption analysis, FT-IR, TGA and DTA. The catalytic performance was investigated in the esterification of several carboxylic acids with different alcohols. The reactions were carried out in a 1:3 carboxylic acid/alcohol molar ratio at 100 °C and atmospheric pressure for 3h. The acid-activated clays provided good yields and better performance than commercial clay K10.
- Rezende, Michelle J. C.,Pereira, Mi?rian S. C.,Santos, Gabriel F. N.,Aroeira, Gabriel O. P.,Albuquerque Jr., Tiago C.,Suarez, Paulo A. Z.,Pinto, Angelo C.
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experimental part
p. 1209 - 1215
(2012/10/08)
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- Dodecanoic acid derivatives: Synthesis, antimicrobial evaluation and development of one-target and multi-target QSAR models
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In this study a series of dodecanoic acid derivatives (1-30) were synthesized and evaluated for in vitro antimicrobial activity against the panel of Gram positive, Gram negative bacterial and fungal strains. 4-Nitro phenyl dodecanoate (4) and quinolin-8-yl dodecanoate (5) emerged as most effective antibacterial agents, and 1-(4-benzylpiperazin- 1-yl) dodecan-1-one (15) was found to be the most effective antifungal agent amongst the synthesized dodecanoic acid derivatives. Quantitative structure activity relationship (QSAR) studies performed by the development of one-target and multi-target models indicated that multitarget model was effective in describing the antimicrobial activity of dodecanoic acid derivatives as well demonstrated the importance of topological parameter, zero-order molecular connectivity index (0X). Springer Science+Business Media, LLC 2010.
- Sarova, Devinder,Kapoor, Archana,Narang, Rakesh,Judge, Vikramjeet,Narasimhan, Balasubramanian
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experimental part
p. 769 - 781
(2012/05/20)
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- An improved greener esterification of fatty alcohols using a renewable acid-ionic liquid couple as catalyst-solvent
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We have developed a simple and efficient method for the esterification of various organic acids with C4-C18 alcohols using the 1-octyl-3-methyl- imidazolium tetrafluoroborate-para-toluenesulphonic acid (OMIM/BF 4-PTSA) couple, without organic solvent, either by classic heating or by microwave irradiation. The utilisation of the OMIM/BF4-PTSA couple presents considerable advantages: high yield, low temperature, short reaction time, isolation of the ester by simple decantation, easy reuse of the catalyst couple.
- Nguyen, Hoang-Phuong,Znifeche, Samira,Baboulene, Michel
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p. 2085 - 2093
(2007/10/03)
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- Pharmaceutical compositions for transdermal administration of anti-inflammatory agents
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The invention concerns a pharmaceutical composition for transdermal administration comprising: a polymeric release matrix capable of forming a soft film after drying, selected among cellulose polymers or copolymers, said matrix being present at a concentration not exceeding 6% of the composition weight; an active principle selected among the group of non-steroid anti-inflammatory agents comprising at least a metal carboxylic or carboxitate group; a transcutaneous absorption promoter of the active principle; water; and at least a physiologically acceptable non-aqueous solvent capable of dissolving the release matrix, the active principle and transcutaneous absorption promoter and to be rapidly eliminated by evaporation in contact with the skin.
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- Organometallic substrates of enzymes: lipase catalysed transesterifications in organic solvents via O-stannyl ethers
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Lipases from pig pancreas and from Chromobacterium viscosum (but not from Candida cylindracea) catalyze transesterification reactions between ethyl esters of carboxylic acids and tributylstannyl ethers of primary and secondary alcohols.At concentrations 1M or higher in anhydrous hydrocarbons, use of these nucleophilic derivatives of alcohols gives reaction rates ca. three times higher than those for the corresponding alcohols.
- Therisod, Michel
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- Fat Hydrolysis and Esterification by a Lipase from Humicola lanuginosa
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The hydrolysis and esterification by a thermostable lipase from Humicola lanuginosa No. 3 were investigated.Both reactions occurred readily at temperatures between 45-50 deg C.Esterification by the enzyme with glycerol was observed to be specific towards fatty acids with carbon numbers of C12-C18.Lauric acid esters with different alcohols such as primary alcohols, terpene alcohols, etc., were also synthesized readily.Esterification by the enzyme was adversely affected by the water content (optimum, ca. 7percent), however, the hydrolysis rate increased rapidly with increasing water content (optimum, ca. 60percent).The enzyme showed increased activity in organic solvent-aqueous reaction systems.Nevertheless, hydrolysis in complete organic phase reactions was found not to be feasible.Hydrolysis at a higher temperature (50 or 55 deg C) in a solvent free phase was almost the same as that in organic solvent-aqueous phase reactions.The components of glycerides varied considerably during hydrolysis, whereby esterification resulted in a higher quantity of mono- and diglycerides (about 40percent), compared to in the case of hydrolysis, for which the value was about 10-20percent.
- Omar, Ibrahim Che,Nishio, Naomichi,Nagai, Shiro
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p. 2153 - 2160
(2007/10/02)
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- Recovery of mercaptoalkanoic acids using alkylene glycol ethers
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Various mercaptoalkanoic acids are recovered from an aqueous medium or water in which they are contained by a liquid-liquid solvent extraction operation employing at least one of an alkanoic acid ester and an alkylene glycol ether. In one embodiment, thioglycolic acid has been extracted with ethyl acetate. In another embodiment, it has been recovered with ethylene glycol monoethyl ether acetate. In a further embodiment, it has been recovered with diethylene glycol diethyl ether.
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- Effect of Inverse Micelles on the Competition between Lactonization and Polymerization Reactions of an ω-Hydroxy Carboxylic Acid
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The ability of inverse micelles to influence the competition between carbodiimide-mediated lactonization and polymerization of 15-hydroxypentadecanoic acid (1), yielding pentadecanolide (2) and polymer (3), respectively, has been investigated by using inverse micellar systems in benzene based on di-n-dodecyldimethylammonium bromide (DDABr) and on bis(2-ethylhexyl) sodium sulfosuccinate (AOT) with and without water pools.Two ionic carbodiimides, 1-cyclohexyl-3-carbodiimide p-toluenesulfonate (4) and 1--3-ethylcarbodiimide hydrochloride (5), were used.The inherent ability of carbodiimide 4 to effect lactonization of 1 is inhibited moderately by DDABr inverse micelles without water pools and completely by AOT inverse micelles without water pools.Carbodiimide 4 did not effect esterification when these inverse micellar systems contained water pools; carbodiimide 5 apparently did not do so under any of the conditions used.
- Jaeger, David A.,Ippoliti, J. Thomas
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p. 4964 - 4968
(2007/10/02)
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