Enthalpies of solution of urea in water–alkanol mixtures and the enthalpic pair interaction coefficients of urea and several nonelectrolytes in water

1986 ◽  
Vol 64 (9) ◽  
pp. 1721-1724 ◽  
Author(s):  
Henryk Piekarski ◽  
Gus Somsen
Keyword(s):  
Heat Capacity ◽  
Hydrophobic Hydration ◽  
High Water ◽  
Pair Interaction ◽  
Heat Capacity Change ◽  
High Water Content ◽  
Enthalpies Of Solution ◽  
Interaction Coefficients ◽  
Enthalpic Pair Interaction Coefficients ◽  
Capacity Change

Enthalpies of solution of urea in binary mixtures of isopropanol, s-butanol, and ethoxyethanol with water have been measured at high water content. Those in the binaries isopropanol + water and ethoxyethanol + water show endothermic maxima at 8 and 4 mol% alkanol, respectively. Enthalpic pair interaction coefficients are calculated for the interactions between urea and the alkanols and discussed in connection with these coefficients for interactions between urea and other nonelectrolytes and between N,N-dimethylformamide and several nonelectrolytes. The enthalpic pair interaction coefficients correlate linearly with the heat capacity change on hydration of the nonelectrolytes and with the enthalpy of hydrophobic hydration of the alkanols.

Dissolution enthalpy of NaCl in aqueous nonelectrolyte solutions at 298.15 K. Analysis of electrolyte–nonelectrolyte enthalpic pair interaction coefficients in aqueous solution

1986 ◽  
Vol 64 (11) ◽  
pp. 2127-2131 ◽  
Author(s):  
Henryk Piekarski
Keyword(s):  
Water Structure ◽  
Vapour Phase ◽  
Pair Interaction ◽  
Point Of View ◽  
Enthalpies Of Solution ◽  
High Dilution ◽  
Interaction Coefficients ◽  
Enthalpic Pair Interaction Coefficients ◽  
Nonelectrolyte Molecule ◽  
Heat Capacity Of Transfer

Enthalpies of solution of NaCl in aqueous solutions of isopropanol, s-butanol, 2-methoxyethanol, 2-ethoxyethanol, acetone, and N,N-dimethylformamide were measured. The results of enthalpy measurements were analyzed from the point of view of the effect of added nonelectrolyte on water structure, and enthalpic pair interaction coefficients hxy{(Na+ + Cl−)–nonelectrolyte} were calculated and compared with appropriate data for (Na+ + I−)–nonelectrolyte pairs. The group additivity concept appeared to be useful for the analysis of calculated hxy coefficients. The correlations between hxy and the functions characterizing different properties of the solutes under study were examined. It was shown that the correlation with the heat capacity of transfer of the nonelectrolyte molecule from the vapour phase to high dilution in water was the most promising. The interpretation of observed correlations was proposed.

scholarly journals Heat capacity change for ribonuclease A folding

1999 ◽  
Vol 8 (7) ◽  
pp. 1500-1504 ◽  
Author(s):  
C. Nick Pace ◽  
Gerald R. Grimsley ◽  
Susan T. Thomas ◽  
George I. Makhatadze
Keyword(s):  
Heat Capacity ◽  
Ribonuclease A ◽  
Heat Capacity Change ◽  
Capacity Change

scholarly journals Temperature control technology by heat capacity change upon lock and key binding

2010 ◽  
Vol 375 (2) ◽  
pp. 165-169 ◽  
Author(s):  
Ken-ichi Amano ◽  
Daisuke Miyazaki ◽  
Liew Fong Fong ◽  
Paul Hilscher ◽  
Taro Sonobe
Keyword(s):  
Heat Capacity ◽  
Temperature Control ◽  
Heat Capacity Change ◽  
Control Technology ◽  
Capacity Change

scholarly journals Thermodynamics of DNA: heat capacity changes on duplex unfolding

2019 ◽  
Vol 48 (8) ◽  
pp. 773-779 ◽  
Author(s):  
Anatoliy Dragan ◽  
Peter Privalov ◽  
Colyn Crane-Robinson
Keyword(s):  
Heat Capacity ◽  
Accessible Surface Area ◽  
Solvent Accessible Surface Area ◽  
Polar Component ◽  
Heat Capacity Change ◽  
Dna Duplex ◽  
Capacity Change ◽  
Heat Capacity Changes ◽  
Accessible Surface ◽  
Lower Magnitude

Abstract The heat capacity change, ΔCp, accompanying the folding/unfolding of macromolecules reflects their changing state of hydration. Thermal denaturation of the DNA duplex is characterized by an increase in ΔCp but of much lower magnitude than observed for proteins. To understand this difference, the changes in solvent accessible surface area (ΔASA) have been determined for unfolding the B-form DNA duplex into disordered single strands. These showed that the polar component represents ~ 55% of the total increase in ASA, in contrast to globular proteins of similar molecular weight for which the polar component is only about 1/3rd of the total. As the exposure of polar surface results in a decrease of ΔCp, this explains the much reduced heat capacity increase observed for DNA and emphasizes the enhanced role of polar interactions in maintaining duplex structure. Appreciation of a non-zero ΔCp for DNA has important consequences for the calculation of duplex melting temperatures (Tm). A modified approach to Tm prediction is required and comparison is made of current methods with an alternative protocol.

Heat capacity change on isothermal vitrification during a macromolecule's growth

1993 ◽  
Vol 201 (1-3) ◽  
pp. 95-100 ◽  
Author(s):  
M. Cassettari ◽  
G. Salvetti ◽  
E. Tombari ◽  
S. Veronesi ◽  
G.P. Johari
Keyword(s):  
Heat Capacity ◽  
Heat Capacity Change ◽  
Capacity Change

scholarly journals Glucosylation of β-lactoglobulin lowers the heat capacity change of unfolding; a unique way to affect protein thermodynamics

2005 ◽  
Vol 14 (8) ◽  
pp. 2187-2194 ◽  
Author(s):  
Annemarie M.M. Van Teeffelen ◽  
Kerensa Broersen ◽  
Harmen H.J. de Jongh
Keyword(s):  
Heat Capacity ◽  
Heat Capacity Change ◽  
Protein Thermodynamics ◽  
Capacity Change ◽  
Β Lactoglobulin

Aqueous Solutions of Nonpolar Compounds. Heat-Capacity Effects

1972 ◽  
Vol 50 (2) ◽  
pp. 133-138 ◽  
Author(s):  
R. D. Wauchope ◽  
R. Haque
Keyword(s):  
Heat Capacity ◽  
Temperature Coefficient ◽  
Solution Process ◽  
Positive Temperature Coefficient ◽  
Heat Capacity Change ◽  
Positive Temperature ◽  
Capacity Change ◽  
Heat Capacity Changes ◽  
Nonpolar Compounds ◽  
Better Than

The method of Clarke and Glew has been used to obtain estimates of the precision of measurement of the thermodynamic functions for the solution of hydrocarbons, the noble gases, and inert diatomic gases in water. In some cases, the precision of the data is such that a statistically significant value for the temperature coefficient of the heat-capacity change for the solution process is obtained. Comparison with the theory of Nemethy and Scheraga shows that their calculations of heat-capacity changes at 25 °C are better than previously believed, but that their prediction of a positive temperature coefficient for this quantity is in contradiction with most data.

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