The Enthalpy of Interaction of Nonelectrolyte Pairs in Dilute Aqueous Solutions.

摘要

The enthalphy of dilution of single- and binary-solute aqueous mixtures of a series of compounds were measured from about 0.2 to 2 mol/kg at 25 C. The compounds included in the study were N-methylformamide, N-methylacetamide, N-methylpropionamide, N-butylacetamide, urea, ethylene glycol, pentaerythritol, glucose and sucrose. The apparent molal volumes of each solute in dilute aqueous solutions were measured at 0, 25, and 45 C. A statistical analysis of the excess enthalpy data showed that solute-pair heats of interaction could be roughly represented by a sum of several independent group interactions. The sign and magnitude of the six interactions between a CH2, CONH and CHOH functional group are reported. These group interaction values were used to calculate the pairwise heats of interaction for several previously reported nonelectrolytes to within 45 cal kg/sq. mol of prior experimental values. (Author)