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

Abstract

HENRYK PIEKARSKI. Can. J. Chem. 64, 2127Chem. 64, (1986. 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 h,, {(Na' + C1-)-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 h,, coefficients. The correlations between h,, 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.HENRYK PIEKARSKI. Can. J. Chem. 64, 2127Chem. 64, (1986. On a mesurC les enthalpies de solution du NaCl dans des solutions aqueuses d'isopropanol, de s-butanol, de mCthoxy-2 Cthanol, d'Cthoxy-2 Cthanol, d'acetone et de N,N-dimCthylformamide. On a analysC les rtsultats des mesures d'enthalpies en fonction de l'effet de I'addition d'Clectrolytes sur le structure de l'eau; de plus, on a calculC les coefficients d'interaction entre les paires enthalpiques [h,,{(NaL + C1)-nonelectrolyte}] et on les a cornparks avec les donnCes appropriCes relatives aux paires (Na+ + I)-nonelectrolyte. Le concept d'additivitk de groupe semble utile pour I'analyse des coefficients h,, calculCs. On a examink les corrClations qui existent entre h,, et les fonctions qui caractkrisent les diverses propriCtCs des solutes CtudiCs. On a dCmontrC que la corrClation avec la capacitC calorifique de transfert de la molCcule nonClectrolyte de la phase vapeur a une grande dilution dans I'eau est celle qui offre le plus de promesses. On propose une interpretation des corrilations observtes.[Traduit par la revue]Thermochemical properties of electrolyte solutions in the mixtures of water with nonelectrolytes are frequently studied in many scientific centres. The obtained results are explained from the point of view of mixed solvent structure as well as solute -mixed solvent interactions. Enthalpic pair interaction coefficients between the solute and cosolvent in solvent water are often regarded as a measure of the interactions that can appear in these systems (1). As it is known the above mentioned coefficients can be calculated among others from experimentally determined enthalpy of transfer of the solute from water to water-cosolvent mixture ( 2 , 3). From the numerous papers devoted to the analysis of the pair interaction coefficients, the most refer to the nonelectrolyte-nonelectrolyte pairs. Only a few papers concern the interactions between an electrolyte and a nonelectrolyte. One of them is a previous publication, prepared in our laboratory, that presents the systematic investigations of...

Thermochemistry of electrolyte solutions

“…In three-component systems including, solute X, solvent S, cosolvent Y, the enthalpic pair interaction coefficients, h xy , illustrate the heat effect of interaction between the solute molecule X and the cosolvent molecule Y in the solvent S. As these interactions are solvent mediated, it can be assumed that their values are the sum of two essential energetic effects, namely partial desolvation of interacting species and direct interaction between them [4][5][6][7]. The values of pair interaction coefficients in three-component systems can be calculated from the enthalpy of solution or enthalpy of mixing [8].…”

Thermochemical properties of electrolyte solutions in {2-(2-methoxyethoxy)ethanol+water} and (2-isopropoxyethanol+water) mixtures at 298.15 K

“…For NaCl solutions, the maximum of D sol H 1 m in the mixtures of water with each 2-alkoxyethanol corresponds to a significantly higher cellosolve content than that for the NaI solutions. In this respect the discussed mixed solvents resemble more closely the mixtures of water with hexamethylphosphortriamide (HMPA), tetrahydrofurane (THF) and 1,2-dimethoxyethane (DME) [21][22][23] than the water-alcohol [24,25] mixed solvent, where the extrema occur for almost the same alcohol content.…”

Studies on the interaction between α-amino acids with polar side-chains and heterocyclic compounds at T=298.15 K

“…The SWAG method has been applied successfully to the nonelectrolyte-nonelectrolyte [17][18][19][20][21] and electrolyte-nonelectrolyte [22][23][24][25] pairs in water. But so far many reports on unbranched chain molecules have been made and no report has been found about heterocyclic compounds.…”