Temperature dependence of enthalpy, entropy, and heat capacity of activation in the neutral ester hydrolysis in 2-butoxyethanol–water solutions

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

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On Temperature Dependence of Excess Gibbs Energy

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19991093 ◽

1999 ◽

Vol 64 (7) ◽

pp. 1093-1099 ◽

Cited By ~ 2

Author(s):

Ivona Malijevská ◽

Anatol Malijevský

Keyword(s):

Heat Capacity ◽

Gibbs Energy ◽

Temperature Dependence ◽

Excess Gibbs Energy ◽

Excess Enthalpy ◽

Excess Heat Capacity ◽

Wilson Equation ◽

Excess Heat ◽

Energy Excess ◽

Wilson And Nrtl Equations

Temperature dependence of GE is discussed for three widely used equations linear and nonlinear in parameters. It is shown that the Wilson equation predicts always positive excess heat capacity regardless of values of its parameters. Several temperature modifications of the Redlich-Kister, Wilson and NRTL equations are discussed with respect to the sign of the excess Gibbs energy, excess enthalpy and excess heat capacity.

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Heat capacity of activation for the hydrolysis of methanesulfonyl chloride and benzenesulfonyl chloride in light and heavy water

Canadian Journal of Chemistry ◽

10.1139/v69-694 ◽

1969 ◽

Vol 47 (22) ◽

pp. 4199-4206 ◽

Cited By ~ 5

Author(s):

R. E. Robertson ◽

B. Rossall ◽

S. E. Sugamori ◽

L. Treindl

Keyword(s):

Heat Capacity ◽

Free Energy ◽

Temperature Dependence ◽

Heavy Water ◽

Bond Formation ◽

Sulfonyl Chlorides ◽

Benzenesulfonyl Chloride ◽

Methanesulfonyl Chloride ◽

Hydrolysis Of ◽

Parameter Temperature Dependence

Rates of solvolysis of methanesulfonyl chloride and benzenesulfonyl chloride have been determined in H2O and D2O. The free energy, enthalpy, entropy, and heat capacity of activation were calculated. The exceptional accuracy of the data permitted an estimation of dΔCp≠/dT from a four parameter temperature dependence of the kinetic rates.From these data we conclude that both sulfonyl chlorides hydrolyse by the same mechanism (Sn2) The change in R from CH3 to C6H5 in RSO2Cl did not alter ΔCp≠ but ΔS≠ (20°) was changed from −8.32 to −13.25 cal deg−1 mole−1, respectively. The significance of this difference is attributed to the probability of bond formation rather than to differences in solvent reorganization.

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