- Thermodynamic properties of some cyclohexyl esters in the condensed state
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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
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- Comprehensive Study of vapor Pressures and Enthalpies of Vaporization of Cyclohexyl Esters
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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
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- A levulinic acid by the method of preparation valeric acid and pentanoate (by machine translation)
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The present invention provides a process for preparing valeric acid and by levulinic acid formylvalerate ester, to levulinic acid as a starting material, the hydrogenation catalyst and trifluoromethanesulfonic acid metal salt as a catalyst, the hydrogen atmosphere catalytic hydrogenolysis reaction, to obtain the valeric acid, continue to valeric acid as the raw material, trifluoromethanesulfonic acid metal salt as catalyst, adding alcohol compound to carry out the esterification reaction, to obtain pentanoate. The invention described in the laevulinic acid preparation valeric acid and formylvalerate ester, it has simple process, mild reaction conditions, high product yield, easy to be purified, environment-friendly and the like, and is suitable for large-scale industrial production. (by machine translation)
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Paragraph 0061-0063; 0070-0072
(2017/08/30)
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- Highly efficient transformation of Γ-valerolactone to valerate esters over structure-controlled copper/zirconia catalysts prepared via a reduction-oxidation route
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Design and development of novel and efficient catalysts are crucial but challenging for the catalytic conversion of biomass and derivatives to fuels and chemicals. In this paper, a novel separate nucleation and aging steps assistant reduction-oxidation strategy was developed to synthesis CuO/ZrO2 complex precursor with homogeneously distributed Cu and Zr components, which can be used as an ideal precursor for the synthesis of highly dispersed Cu/ZrO2 catalyst. Characterization results revealed that homogeneous dispersion of CuO, high surface area of ZrO2 support with controlled porous structure, and strong interaction between CuO and ZrO2 in CuO/ZrO2 precursor could lead to the enhanced Cu dispersion and the formation of Cu+ active centers. The synthesized Cu/ZrO2 catalysts exhibited excellent catalytic performance (85.4% conversion of GVL and 98.0% selectivity of pentyl valerate) in the catalytic transformation of GVL to valerate esters, more efficient than that of Cu/ZrO2-CP and Cu/ZrO2-CH catalysts prepared via co-precipitation and chemisorption hydrolysis methods, respectively. The superior catalytic performance was mainly attributed to both the cooperation of Cu0 and Cu+ species and the highly dispersed surface Cu0, thereby improving the adsorption and polarization of C[dbnd]O bond in GVL and the following dissociation of H2 to produce active hydrogen for the hydrogenation step during the catalytic transformation of GVL. Moreover, such copper-based catalysts exhibited potential applications in the exploitation and utilization of biomass resources with significantly enhanced efficiency.
- Liu, Shanshan,Fan, Guoli,Yang, Lan,Li, Feng
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p. 180 - 188
(2017/07/10)
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- Ruthenium pincer-catalyzed cross-dehydrogenative coupling of primary alcohols with secondary alcohols under neutral conditions
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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
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supporting information
p. 2403 - 2406
(2012/11/07)
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- Ruthenium pincer-catalyzed acylation of alcohols using esters with liberation of hydrogen under neutral conditions
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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
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supporting information; experimental part
p. 3169 - 3173
(2011/02/23)
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- Kinetics of alcoholysis of valeric anhydride by cyclohexanol in the presence of formic acid
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Kinetics of the reaction proceeding at the industrial process of cyclohexane oxidation are studied by the model reaction of the alcoholysis of valeric anhydride by cyclohexanol in the presence of formic acid.
- Kotel'Nikova,Revkov,Voronina,Perkel
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experimental part
p. 466 - 472
(2009/07/10)
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- The thermodynamic properties of cyclohexyl esters in the ideal gas state
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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
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p. 701 - 706
(2007/10/03)
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- Synthesis and Bioevaluation of Alicyclic and Heterocyclic Alkanoates as Cockroach Attractants
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A series of homo and heterocyclic alkanoates were prepared and evaluated as insect attractants toward Blattella germanica (L.) and Supella longipalpa (F.).Among these compounds, the tetrahydrofurfuryl alkanoates and 4-tetrahydropyranyl hexanoate showed relatively better activity.It was also observed that, in general, the five-membered compounds were better performers than their six-membered counterparts.The introdiction of an oxygen atom in the ring enhanced the activity, irrespective of the ring size.
- Pandey, Karuna Shanker,Mendki, Murlidhar Jaywantrao,Rao, Karumuru Mallikarjuna,Vaidyanathaswamy, Ramamoorthy
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p. 725 - 727
(2007/10/02)
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- NONCHAIN CONVERSION OF alpha -DIKETONES AND TRANSACYLATION OF CARBOXYLIC-ACID ANHYDRIDES UNDER AUTOXIDATION CONDITIONS.
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The present investigation produced the following conclusion. The oxidation of 8,9-hexadecanedione by peroxylauric acid in benzene solution conforms to the kinetic equation for a second-order reaction. The oxidation is accompanied by transacylation of the caprylic anhydride formed with lauric acid. The anhydrides formed by transcylation take part in the formation of ester products of autoxidation. Lauric acid actively catalyzes the reaction of 8,9-hexadecanedione with peroxylauric acid.
- Perkel',Freidin,Neginskaya,Stolyankova,Ivanova
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p. 1444 - 1449
(2007/10/02)
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- Esterification of Carboxylic Acids by Alcohols with 2-Chloro-1,3,5-trinitrobenzene as Condensing Agent
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When mixtures of carboxylic acids or their sodium salts and alcohols were treatment with 2-chloro-1,3,5-trinitrobenzene in the presence of pyridine under mild conditions, the corresponding carboxylic esters were formed.The yields and the rates of the ester formation depended on the types of the acids and the alcohols used.
- Takimoto, Seiji,Inanaga, Junji,Katsuki, Tsutomu,Yamaguchi, Masaru
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p. 1470 - 1473
(2007/10/02)
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