- Recyclable and selective Lewis acid catalysts for transesterification and direct esterification in a fluorous biphase system: Tin(IV) and hafnium(IV) bis(perfluorooctanesulfonyl)amide complexes
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Tin(IV) and hafnium(IV) bis(perfluorooctanesulfonyl)amide complexes were shown to give excellent yield and selectivity for highly practical transesterification and direct esterification, respectively, with an equimolar ratio of the reactants in a fluorous biphase system. It was found that these metal complexes were completely recovered and reused in the immobilized fluorous phase without loss of their catalytic activities.
- Hao, Xiuhua,Yoshida, Akihiro,Nishikido, Joji
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Read Online
- Solvent stability study with thermodynamic analysis and superior biocatalytic activity of Burkholderia cepacia lipase immobilized on biocompatible hybrid matrix of poly(vinyl alcohol) and hypromellose
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In the present study, we have synthesized a biocompatible hybrid carrier of hypromellose (HY) and poly(vinyl alcohol) (PVA) for immobilization of Burkholderia cepacia lipase (BCL). The immobilized biocatalyst HY:-PVA:BCL was subjected to determination of half-life time (τ) and deactivation rate constant (KD) in various organic solvents. Biocatalyst showed higher τ-value in a nonpolar solvent like cyclohexane (822 h) as compared to that of a polar solvent such as acetone (347 h), which signifies better compatibility of biocatalyst in the nonpolar solvents. Furthermore, the KD-value was found to be less in cyclohexane (0.843 × 10-3) as compared to acetone (1.997 × 10-3), indicating better stability in the nonpolar solvents. Immobilized-BCL (35 mg) was sufficient to achieve 99% conversion of phenethyl butyrate (natural constituent of essential oils and has wide industrial applications) using phenethyl alcohol (2 mmol) and vinyl butyrate (6 mmol) at 44 °C in 3 h. The activation energy (Ea) was found to be lower for immobilized-BCL than crude-BCL, indicating better catalytic e fficiency of immobilized lipase BCL. The immobilized-BCL reported 6-fold superior biocatalytic activity and 8 times recyclability as compared to crude-BCL. Improved catalytic activity of immobilized enzyme in nonpolar media was also supported by thermodynamic activation parameters such as enthalpy (ΔH?), entropy (ΔS?) and Gibb 's free energy (ΔG?) study, which showed that phenethyl butyrate synthesis catalyzed by immobilized-BCL was feasible as compared to crude-BCL. The present work explains a thermodynamic investigation and superior biocatalytic activity for phenethyl butyrate synthesis using biocompatible immobilized HY:PVA:BCL in nonaqueous media for the first time. (Graph Presented).
- Badgujar, Kirtikumar C.,Bhanage, Bhalchandra M.
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p. 14808 - 14819
(2015/02/19)
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- Sulfonated polypyrene (S-PPR) as efficient catalyst for esterification of carboxylic acids with equimolar amounts of alcohols without removing water
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Sulfonated polypyrene (S-PPR) efficiently catalyzed the reactions between carboxylic acids and equimolar amounts of alcohols with and without heptane to give the corresponding esters in good to excellent yields. Esterification was carried out at 110 °C without removing water. Transesterification of carboxylic esters with a slight excess of alcohols smoothly proceeded without heptane to give the corresponding esters in good yields. For these reactions, S-PPR was recycled without significant loss of activities.
- Tanemura, Kiyoshi,Suzuki, Tsuneo
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p. 1972 - 1975
(2013/04/23)
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- Rapeseed lipase catalyzed synthesis of butyl butyrate for flavour and nutraceutical applications in organic media
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Butyl butyrate, a short chain ester with fine fruity pineapple odour, is a significant flavour compound. Recent investigations show that butyrate esters also have anticancer activity. Factors influencing the synthesis of butyl butyrate by organic phase biocatalysis were investigated. Maximum ester yield of 89% was obtained when 0.25 M butanol and butyric acid were reacted at 25 °C for 48 h in the presence of 250 mg rape seed lipase acetone powder in hexane. Addition of water did not affect synthesis, while a water activity of 0.45 was found optimum. Of 15 different alcohols evaluated, isoamyl and (Z)-3- hexen-1-ol were esterified most effectively with molar conversion yields of 92.2 and 80.2%. Short chain primary alcohols such as methanol and medium-long chain alcohols, such as heptanol and octanol were esterified more slowly. The results show that rape seed lipase is versatile catalyst for ester synthesis with temperature stability range 5-50 °C.
- Liaquat, Muhammad
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experimental part
p. 6 - 13
(2012/06/18)
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- Synthesis of short chain alkyl esters using cutinase from Burkholderia cepacia NRRL B2320
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Short chain alkyl esters are well appreciated for fruity flavors they provide. These are mainly applied to the fruit-flavored products like jam, jelly, beverages, wine and dairy. Cutinase from Burkholderia cepacia NRRL B 2320 was found to be active in catalyzing the synthesis of alkyl esters in organic solvent. The optimal temperature range for the enzyme catalyzed synthesis was found to be from 35 °C to 40 °C. The maximum conversion (%) during synthesis of ester was obtained for butyric acid (C4) and valeric acid (C5) with butanol reflecting the specificity of the enzyme for short-chain length fatty acids. In case of alcohol specificity, butanol was found to be most preferred substrate by the enzyme and conversion (%) decreased with increasing carbon chain length of alcohol used in the esterification reaction. The kinetic analysis for the synthesis of butyl butyrate by varying concentration of one substrate at a time (butanol or butyric acid), showed that Ping-Pong Bi Bi model with acid inhibition and influence of initial water is most suitable model for the prediction of the reaction kinetics.
- Dutta, Kasturi,Dasu, Veeranki Venkata
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experimental part
p. 150 - 156
(2012/07/01)
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- Metal bis(perfluorooctanesulfonyl)amides as highly efficient Lewis acid catalysts for fluorous biphase organic reactions
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In fluorous biphase system, metal bis(perfluorooctanesulfonyl)amides are better Lewis acid catalysts than the analogous triflates toward either transesterifications, or direct esterifications, or Friedel-Crafts acylations or Baeyer-Villiger oxidations. These catalysts are selectively soluble in lower fluorous phase and can be recovered simply by phase separation. Furthermore, these catalysts can be reused without decrease of activity in most cases.
- Hao, Xiuhua,Yoshida, Akihiro,Nishikido, Joji
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p. 193 - 199
(2007/10/03)
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- Iron perchlorate on silica gel as multi-purpose reagent for catalysis of closure and rupture of carbon-oxygen bond in epoxides, alcohols, and esters
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Aliphatic alcohols and water in the presence of catalytic amounts of Fe3+ ion introduced as iron(III) perchlorate on silica gel carrier perform efficient regiospecific opening of an epoxy ring. Carbon acids esterification with various type alcohols was carried out using the system Fe(ClO4)3-silica gel in dichloromethane under conditions excluding solvolysis. Acetylation and formylation of alcohols was performed by efficient transesterification with ethyl acetate and ethyl formate.
- Salechi,Khodaei,Ghareghani,Motlagh
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p. 794 - 796
(2007/10/03)
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- Structure-function correlation in lipase catalysed esterification reactions of short and medium carbon chain length alcohols and acids
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An attempt has been made to correlate the carbon chain lengths of acids and alcohols to the extent of esterification in the Rhizomucor miehei lipase catalyzed esterification reactions involving acids of carbon chain length C2-C5 and alcohols of carbon chain length C1-C8.
- Divakar, Soundar
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p. 1919 - 1922
(2007/10/03)
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- Acylation of alcohols and amines with vinyl acetates catalyzed by Cp*2Sm(thf)2
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Cp*2Sm(thf)2 was found to be an efficient catalyst for the acylation of alcohols and amines with esters under mild conditions. In the present acylation, vinyl and isopropenyl acetates served as good acylating agents. Thus, a variety of alcohols and amines underwent acylation with vinyl and isopropenyl acetates in the presence of Cp*2Sm(thf)2 to give the corresponding esters and amides in good to excellent yields. This catalytic acylation of alcohols and amines offers an additional useful method by the use of various esters, instead of acid anhydrides and acid chlorides, as acylating agents under very mild conditions.
- Ishii, Yasutaka,Takeno, Mitsuhiro,Kawasaki, Yumi,Muromachi, Akifumi,Nishiyama, Yutaka,Sakaguchi, Satoshi
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p. 3088 - 3092
(2007/10/03)
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- An Extremely Simple, Convenient and Selective Method for Acetylation Primary Alcohols in the Presence of Secondary Alcohols
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Reaction of primary-secondary diols with acetyl chloride in dichloromethane in the presence of 2,4,6-collidine, N,N-diisopropylethylamine, or 1,2,2,6,6-pentamethylpiperidine (PMP) leads to the corresponding primary monoacetates simply, conveniently, and in good yields.In this way, other acyl chlorides, sulfonyl chlorides, and silyl chlorides in place of acetyl chloride also react with primary hydroxyl group selectively.
- Ishihara, Kazuaki,Kurihara, Hideki,Yamamoto, Hisashi
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p. 3791 - 3793
(2007/10/02)
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- NEW OXIDATIVE ESTERIFICATION OF ALCOHOLS WITH ALDEHYDES BY THE Br2-HMPT-NaHCO3.
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A new aldehyde-mediated oxidative esterification using a bromine/HMPT complex in the presence of sodium hydrogen carbonate is described.
- Al Neirabeyeh, Mamdouh,Pujol, M. Dolors
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p. 2273 - 2276
(2007/10/02)
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- Synthetic and Mechanistic Aspects of Gas-Liquid Phase-transfer Catalysis: Carboxylate Esters
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The synthesis of esters from solid alkyl- and aryl-carboxylates and gaseous alkyl halides (RX), that is gas-liquid phase-transfer catalysis (g.l.p.t.c.) is promoted by the classical phase-transfer catalysts, quaternary phosphonium salts.The reaction is run under continuous-flow conditions in a column and the product is collected at the outlet.An investigation of the mechanism of the reaction shows the great importance of the liquid film of melted catalyst in promoting anion exchange between the underlying solid carboxylate salt and the gaseous alkyl halide which diffuses and reacts.This technique does not require the use of organic or aqueous solvents, leads to high conversion into esters for low carboxylate: RX molar ratios, and transforms large quantities of reagents with small volumes of solid bed.
- Angeletti, Enrico,Tundo, Pietro,Venturello, Paolo
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p. 993 - 998
(2007/10/02)
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