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Saturation Molalities and Standard Molar Enthalpies of Solution of Adenosine (cr), Guanosine. 2H2O(cr), inosine(cr), and Xanthosine. 2H2O(cr) in H2(l)

Published

Author(s)

Yadu D. Tewari, R Klein, Mark D. Vaudin, Robert N. Goldberg

Abstract

Saturation molalities m(sat) in H2O(l) have been measured for the substances adenosine(cr), guanosine 2H2O(cr), inosine(cr), and xanthosine 2H2O(cr) over the temperature range T = 287.91 K to T = 308.18 K by using h.p.l.c.. The indicated states of hydration of these substances were established by performing Karl Fischer analyses of samples of these substances which had been equilibrated over H2O(l) and of samples obtained by passing air over the wet crystals (air dried samples). The crystalline phases of these substances were identified by comparison of the results of x-ray diffraction measurements with results from the literature. Molar enthalpies of solution {Δ}solHm for adenosine(cr) and inosine(cr) were measured by using an isoperibol solution calorimeter. A stacking or self-association model was used to estimate values of the activity coefficients γ and relative apparent molar enthalpies L{symbol} for these substances. These γ and L{symbol} values were used to adjust the measured values of m(sat) and {Δ}solHm to the standard state and obtain values of the standard molar Gibbs free energy and enthalpy changes {Δ}solG m and {Δ}solH m, respectively, for the dissolution reactions of these substances. Values of {Δ}solH m calculated from the temperature dependence of values of {Δ}solG m were in good agreement with the values of {Δ}solH m obtained by using calorimetry.
Citation
Journal of Chemical Thermodynamics
Volume
35
Issue
10

Keywords

adenosine, calorimetry, enthalpy, entropy, Gibbs free energy guanosine, inosine saturation molality, xanthosine

Citation

Tewari, Y. , Klein, R. , Vaudin, M. and Goldberg, R. (2003), Saturation Molalities and Standard Molar Enthalpies of Solution of Adenosine (cr), Guanosine. 2H<sub>2</sub>O(cr), inosine(cr), and Xanthosine. 2H<sub>2</sub>O(cr) in H<sub>2</sub>(l), Journal of Chemical Thermodynamics (Accessed April 20, 2024)
Created October 1, 2003, Updated February 17, 2017