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

1969 ◽  
Vol 47 (22) ◽  
pp. 4199-4206 ◽  
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.

Studies in Solvolysis. Part VII. The Neutral Hydrolysis of Methyl Perchlorate

1975 ◽  
Vol 53 (20) ◽  
pp. 3106-3115 ◽  
Author(s):  
Ross Elmore Robertson ◽  
Adrianna Annesa ◽  
John Marshall William Scott
Keyword(s):  
Heat Capacity ◽  
Carbon Atom ◽  
Temperature Dependence ◽  
Thermodynamic Parameters ◽  
Isotope Effect ◽  
Perchlorate Ion ◽  
Rate Of Hydrolysis ◽  
Leaving Groups ◽  
Hydrolysis Of

The temperature dependence of the rate of hydrolysis of methyl perchlorate has been measured and the entropy (ΔS≠), enthalpy (ΔH≠), and heat capacity (ΔCp≠) of activation calculated. The measurements confirm that the perchlorate ion is superior to all other leaving groups in water. The isotope effect related to the hydrolysis of methyl-d3 perchlorate has been measured at three temperatures and shown to be inverse. The thermodynamic parameters and the isotope effect were examined with respect to the mechanism of substitution at a primary carbon atom.

The ionization constant of heavy water (D2O) in the temperature range 298 to 523 K

1976 ◽  
Vol 54 (22) ◽  
pp. 3553-3558 ◽  
Author(s):  
David William Shoesmith ◽  
Woon Lee
Keyword(s):  
Heat Capacity ◽  
Free Energy ◽  
Heavy Water ◽  
Electrolyte Concentration ◽  
Aqueous Electrolyte ◽  
Ionization Constant ◽  
Standard Free Energy ◽  
Concentration Cell ◽  
Temperature Range

The ionization constant of liquid D2O has been measured over the temperature range 298 to 523 K using an aqueous electrolyte concentration cell. Values for the standard free energy, enthalpy, entropy, and heat capacity of ionization have been calculated. The results are compared to similar results for liquid H2O

The Hydrolysis of t-Butyl Chloride in Aquo-Organic Mixtures: Heat Capacity of Activation and Solvent Structure

1972 ◽  
Vol 50 (9) ◽  
pp. 1353-1360 ◽  
Author(s):  
R. E. Robertson ◽  
S. E. Sugamori
Keyword(s):  
Heat Capacity ◽  
Temperature Dependence ◽  
High Water ◽  
Remarkable Difference ◽  
Solvent Structure ◽  
Butyl Chloride ◽  
Organic Mixtures ◽  
A Value ◽  
Polar Solutes ◽  
Hydrolysis Of

The temperature dependence of the rate of solvolysis of t-butyl chloride in mixtures of tetrahydrofuran and of acetonitrile in water have been determined. In the high-water range both minor co-solvents lead to a reduction in the value of ΔH≠ similar to that found previously where alcohol was the co-solvent. However, a remarkable difference in the values of [Formula: see text] across the same concentration range reflected a difference in the effect of these two co-solvents on the structural properties of the several solvent media. Where tetrahydrofuran or alcohols are the minor co-solvent, [Formula: see text] becomes much more negative until that concentration is reached where the quasi-aqueous structure collapses. Where acetonitrile is the minor co-solvent [Formula: see text] becomes more positive relative to the value found for hydrolysis in water until a value of about −40 cal deg−1 mol−1 is reached. The implication of these findings concerning the nature of solvation of weakly polar solutes in such mixtures is discussed.

Temperature Dependence of Activation Volumes of Solvolysis Reactions in Light and Heavy Water

1973 ◽  
Vol 51 (11) ◽  
pp. 1687-1692 ◽  
Author(s):  
Claude S. Davis ◽  
J. B. Hyne
Keyword(s):  
Temperature Dependence ◽  
Heavy Water ◽  
Pressure Dependence ◽  
Benzyl Chloride ◽  
Methanesulfonyl Chloride ◽  
Extensive Data

The pressure dependence of the solvolysis rates for benzyl chloride, isopropyl bromide, and methanesulfonyl chloride in H2O and D2O have been measured. The temperature dependence of the activation volumes appears to be indicative of the mechanism of solvolyses and the differences in the temperature dependence of the activation volumes for the two solvents are consistent with D2O being the more structured. The more extensive data in the case of methanesulfonyl chloride deuterolysis indicates extremum behavior in ΔV* as a function of temperature in the 5–25 °C range.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

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.

Salt effect in hydrolysis of 3-acyl-1,3-diphenyltriazenes

1981 ◽  
Vol 46 (12) ◽  
pp. 3104-3109 ◽  
Author(s):  
Miroslav Ludwig ◽  
Oldřich Pytela ◽  
Miroslav Večeřa
Keyword(s):  
Sodium Chloride ◽  
Temperature Dependence ◽  
Potassium Chloride ◽  
Rate Constants ◽  
Zinc Sulphate ◽  
Salt Effect ◽  
Sodium Sulphate ◽  
Potassium Sulphate ◽  
Lithium Sulphate ◽  
Hydrolysis Of

Rate constants of non-catalyzed hydrolysis of 3-acetyl-1,3-diphenyltriazene (I) and 3-(N-methylcarbamoyl)-1,3-diphenyltriazene (II) have been measured in the presence of salts (ammonium chloride, potassium chloride, lithium chloride, sodium chloride and bromide, ammonium sulphate, potassium sulphate, lithium sulphate, sodium sulphate and zinc sulphate) within broad concentration ranges. Temperature dependence of the hydrolysis of the substrates studied has been measured in the presence of lithium sulphate within temperature range 20° to 55 °C. The results obtained have been interpreted by mechanisms of hydrolysis of the studied substances.

On Temperature Dependence of Excess Gibbs Energy

1999 ◽  
Vol 64 (7) ◽  
pp. 1093-1099 ◽  
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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