Vaporization Of Esters Research Articles

Thermogravimetric and combustion efficiency analysis of Jatropha curcas biodiesel and its derivatives

Thermal behavior of diesel, Jatropha curcas methyl ester (JOME), and its B20 blend (20% biodiesel and 80% diesel) are examined from the profiles of thermogravimetry – differential scanning calorimetry (TG-DSC) under air. TG profiles of samples indicate the mass loss steps to volatilization and combustion of methyl esters. Due to the higher temperature combustion of the intermediate stable compounds that are formed, the peak temperature of combustion is high for JOME compared to diesel and B20 blend. DSC profiles of diesel and B20 JOME indicate an endothermic peak associated with the vaporization of methyl esters for B20 JOME and the volatilization of a small fraction of the diesel. The ignition temperature for diesel and B20 blend is 128 °C, whereas JOME has an ignition temperature of 220 °C. The burnout temperatures for the diesel, JOME, and B20 blend are 283.24, 470.02, and 376.92 °C, respectively. The ignition index for the B20 blend was found to be 73.73% more compared to diesel. The combustion index for the B20 blend was found to be 37.81% higher compared to diesel. The B20 blend exhibits high enthalpy, better thermal stability, and a reduced peak temperature of combustion, with an improved combustion index and an intensity of combustion making it nearly comparable with diesel.

Thermochemistry of Heteroatomic Compounds. Enthalpy of Dissolution and Vaporization of Selected Trimethylsilyl Di- and Tetrathiophosphates

Enthalpy of vaporization (ΔvapH°) of trimethylsilyl esters of dithio- and tetratiophosphoric acids (RX)2P(S)SSiMe3 (X = O, S) have been determined from the experimentally determined enthalpies of their dissolution (ΔdissH°) in n-hexane at 296–298 K and the values of molar refraction (MRD) with correction a for the branching of the carbon substituent according to the equation ΔvapH° = ΔdH°(n-hexane) + 4.39 + 1.05(MRD − α). The obtained vaporization values can be used to calculate the heats of formation of similar, thermally unstable, compounds for experimental calorimetry.

Vapor pressure and enthalpy of vaporization of trimethylolpropane and carboxylic acids esters

Vapor pressure and molar standard enthalpies of vaporization of esters of 2-ethyl-2-(hydroxymethyl)-1,3-propandiol (trimethylolpropane, TMP) and straight and branched carboxylic acids with chain length C1, C3-C6, were determinated by the transpiration method. A linear correlation of vaporization enthalpies of trimethylolpropane esters with the number of carbon atoms and with the Kovat's indices on the non-polar DB-1 GC column has been found. Enthalpies of vaporization of tested compounds were also calculated by QSPR-method. These results were checked by experimental values.

Estimation of Vapor Pressures and Enthalpies of Vaporization of Biodiesel-Related Fatty Acid Alkyl Esters. Part 2. New Parameters for Classic Vapor Pressure Correlations

In Part I of this series of articles, predictive models capable of estimating vapor pressures and enthalpies of vaporization of biodiesel-related esters have been reviewed. In this study, we propose component-specific parameters for classic vapor pressure correlations. First, the previously collected database was evaluated and used in the regression of Antoine coefficients for all compounds. Then, a constrained regression methodology was employed to generate extrapolatable Wagner parameters for the esters whose experimental critical properties were available. Finally, expressions derived from the Clausius–Clapeyron equation have been investigated for the estimation of enthalpies of vaporization. A comparative analysis of the results produced by our parameters and by others available in the literature encourages the use of our values in future applications.

Temperature dependences of saturated vapor pressure and the enthalpy of vaporization of n-pentyl esters of dicarboxylic acids

The saturated vapor pressures and enthalpies of vaporization of n-pentyl esters of linear С2–С6 dicarboxylic acids are determined by the transpiration method in the temperature range of 309.2–361.2 K. The dependences of enthalpies of vaporization on the number of carbon atoms in the molecule and on the retention indices have been determined. The predictive capabilities of the existing calculation schemes for estimation of enthalpy of vaporization of the studied compounds have been analyzed.

Prediction of enthalpies of vaporization based on modified Randič indices. Esters

In the work a prediction method based on modified Randic indices to estimate the enthalpies of vaporization under standard conditions Δvap H 0(298.2) is proposed for esters with different structures and numbers of ester groups. It is shown that the proposed method enables the prediction of enthalpies of vaporization of esters with an accuracy as good as experimental.

Saturated vapor pressures and the enthalpies of vaporization of dicyclohexyl esters of dicarboxylic acids

Saturated vapor pressures at 320–370 K and the enthalpies of vaporization of dicyclohexyl esters of linear dicarboxylic acids containing two to six carbon atoms were determined by the transpiration method. Linear correlations of the enthalpies of vaporization of the esters with the number of carbon atoms in molecules and Kovats retention indices were obtained.

Comprehensive Study of Vapor Pressures and Enthalpies of Vaporization of Cyclohexyl Esters

Vapor pressures and standard molar enthalpies of vaporization were determined for five cyclohexyl esters: cyclohexyl formate, cyclohexyl acetate, cyclohexyl propanoate, cyclohexyl butyrate, and cy...

Improved Benson Increments for the Estimation of Standard Enthalpies of Formation and Enthalpies of Vaporization of Alkyl Ethers, Acetals, Ketals, and Ortho Esters

This work was undertaken for the evaluation and revision of group-additivity values necessary for predicting standard enthalpies of formation and enthalpies of vaporization of ethers, acetals, ketals, and ortho esters by means of Benson's group-additivity methodology. The database on the standard molar enthalpies of vaporization has been extended with measurements on several acetals, ketals, and ortho esters using the transpiration method. The standard molar enthalpies of formation of alkyl ethers, acetals, ketals, and ortho esters were derived using the data for the from the literature and the present results for the enthalpies of vaporization or sublimation. The current database of experimental data for enthalpies of formation and enthalpies of vaporization at 298.15 K have been used to reevaluate the values of the Benson's increments for of alkyl ethers, acetals, ketals, and ortho esters. The group-additivity parameters and strain corrections useful in the application of the Benson's correlation are presented in tabular form, together with a description of their evaluation.

ChemInform Abstract: ENTHALPY DATA OF LIQUIDS. XX. HEATS OF VAPORIZATION OF ALKYL ESTERS OF FORMIC, ACETIC AND PROPIONIC ACIDS

Chemischer InformationsdienstVolume 12, Issue 13 Article ChemInform Abstract: ENTHALPY DATA OF LIQUIDS. XX. HEATS OF VAPORIZATION OF ALKYL ESTERS OF FORMIC, ACETIC AND PROPIONIC ACIDS V. SVOBODA, V. SVOBODASearch for more papers by this authorV. UCHYTILOVA, V. UCHYTILOVASearch for more papers by this authorV. MAJER, V. MAJERSearch for more papers by this authorJ. PICK, J. PICKSearch for more papers by this author V. SVOBODA, V. SVOBODASearch for more papers by this authorV. UCHYTILOVA, V. UCHYTILOVASearch for more papers by this authorV. MAJER, V. MAJERSearch for more papers by this authorJ. PICK, J. PICKSearch for more papers by this author First published: March 31, 1981 https://doi.org/10.1002/chin.198113100AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume12, Issue13March 31, 1981 RelatedInformation

Heats of vaporization of esters by the gas chromatography–calorimetry method

A recently developed gc–calorimetry procedure involving a combination of gas chromatography and heat of solution measurements has been used to measure heats of vaporization of 17 esters, including methyl 2,2-dimethylpropanoate, butyl acetate, glyceryl triacetate, diethyl phthalate, methyl 9-octadecenoate, and 12 methyl esters of C3- to C15-fatty acids. Comparison with measurements of ΔHv reported in the literature indicates that the gc–calorimetry method often has smaller uncertainties in measurements (0.25 to 1.00 kJ mol−1) and more consistent methylene increments for the series of fatty acid methyl esters. Two of the experimental ΔHv measurements which differ appreciably from recent literature values have been verified by vaporization calorimetry.

Heats of vaporization of alkyl esters of formic, acetic and propionic acids

Heats of vaporization of ethyl, propyl, butyl esters of formic acid, methyl, ethyl, propyl and butyl esters of acetic acid and methyl, ethyl and propyl esters of propionic acid were measured. These measurements reassume and complete data known from the literature. From the combination of values of heats of vaporization, the cohesive and vaporization internal energies of the set investigated were computed in the dependence on temperature.

ChemInform Abstract: ENTHALPY DATA OF LIQUIDS. PART VII. HEATS OF VAPORIZATION OF ALKYL ESTERS OF FORMIC ACID

Chemischer InformationsdienstVolume 7, Issue 16 Article ChemInform Abstract: ENTHALPY DATA OF LIQUIDS. PART VII. HEATS OF VAPORIZATION OF ALKYL ESTERS OF FORMIC ACID J. CIHLAR, J. CIHLARSearch for more papers by this authorV. HYNEK, V. HYNEKSearch for more papers by this authorV. SVOBODA, V. SVOBODASearch for more papers by this authorR. HOLUB, R. HOLUBSearch for more papers by this author J. CIHLAR, J. CIHLARSearch for more papers by this authorV. HYNEK, V. HYNEKSearch for more papers by this authorV. SVOBODA, V. SVOBODASearch for more papers by this authorR. HOLUB, R. HOLUBSearch for more papers by this author First published: April 20, 1976 https://doi.org/10.1002/chin.197616064Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume7, Issue16April 20, 1976 RelatedInformation

Heats of vaporization of alkyl esters of formic acid

Heats of vaporization of alkyl esters of formic acid