Relationship of the solvation enthalpies of n-alkanes in a methanol–hexamethylphosphortriamide mixture to its thermal and bulk properties

Abstract

Enthalpies of dissolution are determined thermochemically under standard conditions, and the solvation enthalpies of n-hexane, n-decane, and n-hexadecane in a mixed methanol–hexamethylphosphor-triamide (HMPT) solvent are calculated. Experimental data are compared to values obtained from model calculations. It is shown that positive deviations of the enthalpies of dissolution of alkanes in a МеОН–HMPT mixture from additivity in the range enriched with methanol are due to changes in the bulk properties of the mixed solvent, while negative deviations of enthalpies of dissolution from additivity in the range enriched with HMPT are due to the selective solvation of alkanes by HMPT.