- Consecutive addition esterification and hydrolysis of cyclic olefins catalyzed by multi-SO3H functionalized multi heteropolyanion-based ionic hybrids undersolvent-free conditions
-
An efficient protocol for the synthesis of cycloalkyl carboxylates and alcohols from cyclic olefins is described. The cyclic olefins were converted to corresponding target molecules under solvent-free conditions catalyzed by two novel multi-SO3H functionalized multi heteropolyanion-based ionic hybrids through one-pot consecutive addition esterification and hydrolysis reactions. This approach has several advantages, including high yield, simple workup and simple purification.
- Zheng, Guocai,Li, Xinzhong
-
p. 933 - 941
(2019/03/17)
-
- 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
-
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.
-
p. 14808 - 14819
(2015/02/19)
-
- Graphite oxide as an efficient solid reagent for esterification reactions
-
Esterification of organic acids with alcohols under mild conditions in high yields using graphite oxide, a readily available and inexpensive material, as an effective reagent is described.
- Mirza-Aghayan, Maryam,Rahimifard, Mahshid,Boukherroub, Rabah
-
p. 859 - 864
(2014/12/10)
-
- Ruthenium pincer-catalyzed cross-dehydrogenative coupling of primary alcohols with secondary alcohols under neutral conditions
-
Cross-dehydrogenative coupling of primary alcohols with secondary alcohols to obtain mixed esters with the liberation of molecular hydrogen is achieved in high yield and good selectivity under neutral conditions, using a bipyridyl-based PNN ruthenium(II) pincer catalyst. Copyright
- Srimani, Dipankar,Balaraman, Ekambaram,Gnanaprakasam, Boopathy,Ben-David, Yehoshoa,Milstein, David
-
supporting information
p. 2403 - 2406
(2012/11/07)
-
- Ruthenium pincer-catalyzed acylation of alcohols using esters with liberation of hydrogen under neutral conditions
-
Acylation of secondary alcohols using non-activated esters, in particular symmetrical esters (such as ethyl acetate), is achieved under neutral conditions with the liberation of molecular hydrogen. This unprecedented, environmentally benign reaction is homogenously catalyzed by a dearomatized ruthenium pincer PNN complex. Copyright
- Gnanaprakasam, Boopathy,Ben-David, Yehoshoa,Milstein, David
-
supporting information; experimental part
p. 3169 - 3173
(2011/02/23)
-
- 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
-
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
-
p. 781 - 785
(2007/10/03)
-
- The thermodynamic properties of cyclohexyl esters in the ideal gas state
-
Molecular and spectral data were used to calculate the thermodynamic properties of cyclohexyl formate, cyclohexyl acetate, cyclohexyl propionate, cyclohexyl butyrate, and cyclohexyl valerate in the temperature range 100-1000 K by the method of statistical thermodynamics. The geometry and internal rotation parameters of the molecules were determined by molecular mechanics with the MM3 force field. The frequencies in the vibrational spectra of the molecules were calculated and assigned. The assumption of independent top rotations was found to be too crude for cyclohexyl valerate. The entropies of gaseous cyclohexyl formate, cyclohexyl acetate, and cyclohexyl butyrate calculated at 298.15 K were in close agreement with the experimental values.
- Paulechka,Zaitsau,Kabo,Blokhin
-
p. 701 - 706
(2007/10/03)
-
- Comprehensive Study of vapor Pressures and Enthalpies of Vaporization of Cyclohexyl Esters
-
Vapor pressures and standard molar enthalpies of vaporization Δ lgHmo were determined for five cyclohexyl esters: cyclohexyl formate, cyclohexyl acetate, cyclohexyl propanoate, cyclohexyl butyrate, and cyclohexyl valerate. The data were obtained from the temperature dependence of the vapor pressure measured by the Knudsen and the transpiration methods. Additionally, the standard molar enthalpies of vaporization ΔlgHm o of the same cyclohexyl esters were measured calorimetrically. An analysis of the results obtained from three independent methods has allowed us to improve the determination of the enthalpies of vaporization by the Knudsen effusion method.
- Zaitsau, Dzmitry H.,Verevkin, Sergey P.,Paulechka, Yauheni U.,Kabo, Gennady J.,Viktor M. Sevruk
-
p. 1393 - 1400
(2007/10/03)
-
- Thermodynamic properties of some cyclohexyl esters in the condensed state
-
The heat capacities and the enthalpies of phase transitions of cyclohexyl esters (formate, acetate, butyrate, and valerate) in the condensed state between T = (5 and 320) K were measured in a vacuum adiabatic calorimeter. It was found that all liquid compounds were supercooled by cooling them from T = 300 K at a rate of (0.02 to 0.03) K · s-1 and formed glasses. Crystalline phases were obtained for all esters and the residual entropies of glasses at T → 0 were evaluated. The glass transition temperatures and the heat capacity jumps accompanying the glass transitions, as well as the thermodynamic parameters of fusion of crystalline phases, were determined for all the esters. The molar thermodynamic functions of the investigated compounds in the crystalline, liquid, supercooled liquid, and glassy states were obtained. The regular changes of some thermodynamic properties in the series of cyclohexyl esters are discussed.
- Kozyro,Blokhin,Kabo,Paulechka
-
p. 305 - 331
(2007/10/03)
-
- Selective Conjugate Reduction of α,β-Unsaturated Esters and Amides via SmI2-Promoted Electron Transfer Process
-
α,β-Unsaturated esters and amides were rapidely and selectively reduced to the coresponding saturated ones under mild conditions without affecting coexisting isolated double or triple bonds by using the reduction system, SmI2-N,N-dimethylacetamide (DMA)-proton source.
- Inanaga, Junji,Sakai, Shino,Handa, Yuichi,Yamaguchi, Masaru,Yokoyama, Yasuo
-
p. 2117 - 2118
(2007/10/02)
-
- NEW OXIDATIVE ESTERIFICATION OF ALCOHOLS WITH ALDEHYDES BY THE Br2-HMPT-NaHCO3.
-
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
-
p. 2273 - 2276
(2007/10/02)
-
- Organometallic substrates of enzymes: lipase catalysed transesterifications in organic solvents via O-stannyl ethers
-
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
-
-
- The Esterification of Carboxylic Acid with Alcohol over Hydrous Zirconium Oxide
-
The esterification of carboxylic acids with alcohols proceeded efficienly with hydrous zirconium oxide to give the corresponding esters in the vapor phase, in the liquid phase, and in an autoclave.The steric hindrance of carboxylic acids and alcohols affected the esterification by lowering the reactivity.With a rise in the reaction temperature, the conversion of the carboxylic acid increased.The dehydration of alcohols was prevented by using hydrous zirconium oxide in spite of the high reaction temperature.The reaction rate is first-order with respect to the concentration of the catalyst and an alcohol and is inversely proportional to thta of the carboxylic acid.Transesterification also proceeded efficiently.
- Takahashi, Kyoko,Shibagaki, Makoto,Matsushita, Hajime
-
p. 2353 - 2361
(2007/10/02)
-