Derived thermodynamic properties of [o-xylene or p-xylene + (acetic acid or tetrahydro-furan)] at different temperatures and pressures

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

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Kinetics and Mechanism of the Change of the 4-Nitrobenzylthio-System into 4,4′-Diformylazoxybenzene in Alkaline Dioxane-Water Media

Zeitschrift für Naturforschung A ◽

10.1515/zna-1985-1109 ◽

1985 ◽

Vol 40 (11) ◽

pp. 1128-1132

Author(s):

Y. Riad ◽

Adel N. Asaad ◽

G.-A. S. Gohar ◽

A. A. Abdallah

Keyword(s):

Acetic Acid ◽

Sodium Hydroxide ◽

Rate Constants ◽

Main Product ◽

Reaction Medium ◽

Aqueous Dioxane ◽

Proton Abstraction ◽

First Order ◽

Water Media ◽

Different Temperatures

Sodium hydroxide reacts with α -(4-nitrobenzylthio)-acetic acid in aqueous-dioxane media to give 4,4'-diformylazoxybenzene as the main product besides 4,4'-dicarboxyazoxybenzene and a nitrone acid. This reaction was kinetically studied in presence of excess of alkali in different dioxane-water media at different temperatures. It started by a fast reversible a-proton abstraction step followed by two consecutive irreversible first-order steps forming two intermediates (α -hydroxy, 4-nitrosobenzylthio)-acetic acid and 4-nitrosobenzaldehyde. The latter underwent a Cannizzaro's reaction, the products of which changed in the reaction medium into 4,4'-diformylazoxybenzene and 4,4'-dicarboxyazoxybenzene. The rate constants and the thermodynamic parameters of the two consecutive steps were calculated and discussed. A mechanism was put forward for the formation of the nitrone acid.Other six 4-nitrobenzyl, aryl sulphides were qualitatively studied and they gave mainly 4,4'-diformylazoxybenzene beside 4,4'-dicarboxyazoxybenzene or its corresponding azo acid.

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Kinetics and thermodynamic properties related to the drying of 'Cabacinha' pepper fruits

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v20n2p174-180 ◽

2016 ◽

Vol 20 (2) ◽

pp. 174-180 ◽

Cited By ~ 8

Author(s):

Hellismar W. da Silva ◽

Renato S. Rodovalho ◽

Marya F. Velasco ◽

Camila F. Silva ◽

Luís S. R. Vale

Keyword(s):

Experimental Data ◽

Activation Energy ◽

Free Energy ◽

Thermodynamic Properties ◽

Gibbs Free Energy ◽

Removal Rate ◽

Effective Diffusion ◽

Drying Time ◽

Three Samples ◽

Different Temperatures

ABSTRACT The objective of this study was to determine and model the drying kinetics of 'Cabacinha' pepper fruits at different temperatures of the drying air, as well as obtain the thermodynamic properties involved in the drying process of the product. Drying was carried out under controlled conductions of temperature (60, 70, 80, 90 and 100 °C) using three samples of 130 g of fruit, which were weighed periodically until constant mass. The experimental data were adjusted to different mathematical models often used in the representation of fruit drying. Effective diffusion coefficients, calculated from the mathematical model of liquid diffusion, were used to obtain activation energy, enthalpy, entropy and Gibbs free energy. The Midilli model showed the best fit to the experimental data of drying of 'Cabacinha' pepper fruits. The increase in drying temperature promoted an increase in water removal rate, effective diffusion coefficient and Gibbs free energy, besides a reduction in fruit drying time and in the values of entropy and enthalpy. The activation energy for the drying of pepper fruits was 36.09 kJ mol-1.

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Measurement of the thermodynamic properties for the reactive system ethylene glycol–acetic acid

Fluid Phase Equilibria ◽

10.1016/j.fluid.2007.05.030 ◽

2007 ◽

Vol 258 (2) ◽

pp. 115-124 ◽

Cited By ~ 20

Author(s):

Bastian Schmid ◽

Michael Döker ◽

Jürgen Gmehling

Keyword(s):

Acetic Acid ◽

Thermodynamic Properties ◽

Ethylene Glycol ◽

Reactive System

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α-DEUTERIUM KINETIC ISOTOPE EFFECTS IN SOLVOLYSES OF endo-NORBORNYL p-BROMOBENZENESULFONATE

Canadian Journal of Chemistry ◽

10.1139/v65-304 ◽

1965 ◽

Vol 43 (8) ◽

pp. 2254-2258 ◽

Cited By ~ 6

Author(s):

C. C. Lee ◽

Edward W. C. Wong

Keyword(s):

Acetic Acid ◽

Formic Acid ◽

Isotope Effects ◽

Kinetic Isotope Effects ◽

Aqueous Dioxane ◽

Kinetic Isotope ◽

Different Temperatures

endo-Norbornyl-2-d p-bromobenzenesulfonate was synthesized and the isotope effects, as measured by kH/kD, were determined over a range of temperatures for solvolyses in 30% water – 70% dioxane, acetic acid, and formic acid. Values of kH/kD are of the order of 1.20. The data appear to indicate slightly higher isotope effects as the solvents are changed from aqueous dioxane to acetic acid to formic acid, as well as somewhat higher isotope effects at lower temperatures. Possible mechanistic implications of these results are presented. Relative titrimetric acetolysis rates, kexo/kendo, at different temperatures, and enthalpies and entropies of activation for these acetolyses are evaluated and discussed.

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Role of temperature in the numerical analysis of CaO under high pressure

Open Chemistry ◽

10.2478/s11532-009-0117-9 ◽

2010 ◽

Vol 8 (1) ◽

pp. 126-133 ◽

Cited By ~ 4

Author(s):

Purvee Bhardwaj ◽

Sadhna Singh

Keyword(s):

Phase Transition ◽

High Pressure ◽

Numerical Analysis ◽

Thermodynamic Properties ◽

Elastic Constants ◽

Volume Change ◽

Thermodynamical Properties ◽

Phase Transition Pressure ◽

Different Temperatures

AbstractIn this paper we focus on the elastic and thermodynamic properties of the B1 phase of CaO by using the modified TBP model, including the role of temperature. We have successfully obtained the phase transition pressure and volume change at different temperatures. In addition elastic constants and bulk modulus of B1 phase of CaO at different temperatures are discussed. Our results are comparable with the previous ones at high temperatures and pressures. The thermodynamical properties of the B1 phase of CaO are also predicted.

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Thermodynamic Properties of Solutions of the Acrylic Acid in 1,2-Dichloroethane and Acetic Acid

Chemistry & Chemical Technology ◽

10.23939/chcht05.02.123 ◽

2011 ◽

Vol 5 (2) ◽

pp. 123-127 ◽

Cited By ~ 3

Author(s):

Valentin Serheyev ◽

◽

Yuri Kos ◽

Yuri Van-Chin-Syan ◽

◽

...

Keyword(s):

Acetic Acid ◽

Acrylic Acid ◽

Thermodynamic Properties

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Structural Stability and Thermodynamic Properties of (Y2O3)n(n=1-15) Clusters Based on Density Functional Theory

10.22541/au.162196237.76163897/v1 ◽

2021 ◽

Author(s):

Xin Jiang ◽

Zhenming Zhang ◽

Diqiang Luo ◽

Jinglin You ◽

Chaobin Lai

Keyword(s):

Density Functional Theory ◽

Thermodynamic Properties ◽

Yttrium Oxide ◽

Density Functional ◽

Atomic Orbital ◽

Cluster Structure ◽

Functional Theory ◽

Average Binding Energy ◽

Bee Colony ◽

Different Temperatures

The initial configuration of Yttrium oxide clusters (Y2O3)n(n=1-15) was creatively constructed by combining artificial bee colony algorithm with density functional theory. The structures of large and medium-sized yttrium oxide clusters with molecular number greater than 10 were established for the first time, and many new structures that are different from existing research have been obtained. The average binding energy, second-order difference energy, HOMO-LUMO gap, density of states and other properties of the clusters were analyzed. The thermodynamic properties and behavior of nano yttrium oxide clusters at different temperatures and sizes were discussed. Studies have shown that for small-sized clusters, the atomic stacking structure is cage-like, while for medium-sized and large-sized clusters, the composite trapezoidal structure and ellipsoid-like structure are more stable. The nanoclusters tend to be stable as a whole, and the relative stability of the cluster structure is higher when n = 2,4,7,9. The effect of yttrium oxygen atomic orbital on bonding is analyzed. The heat capacity (Cp), enthalpy change (H) and entropy (S) of (Y2O3)n (n=1-15) clusters increase with the increase of temperature (T), and the vibration free energy (Gv) decreases with the increase of T. The stability of the clusters changes in the temperature range of 300K-500K.

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