Effect of Solvent Polarity on Enthalpies of Solvation of Ethylene Oxide Oligomers

Abstract

The enthalpies of dissolution, Δ sol H m ∞ , and solvation, Δ solv H m ∞ , of ether oligomers CH 3 O(CH 2 CH 2 O) n CH 3 (n = 1−4) in ethyl acetate, pyridine, N,Ndimethylformamide, and acetonitrile have been determined from calorimetric measurements at 298.15 K. The values of group contributions of repeated ether units and monoether fragment have been compared on the basis of the additive method.The contributions of ether group to Δ solv H m ∞ for oligomeric and monomeric molecules coincide within their uncertainties for solutions in highly polar solvents, in contrast to non-polar, moderately polar, and H-bonding solvents. The dependence of ether group contributions to Δ solv H m ∞ on the electron pair acceptance index of solvents E T N has been considered.