Effect of excess enthalpies on binary mixtures containing propylene glycols and poly(propylene glycols) + dimethyl carbonate at 308.15 K

Excess enthalpies have been detd. at atm. pressure and at 308.15 K over the entire range of compn. for binary mixts. contg. propylene glycol (PG), dipropylene glycol (DPG), tripropylene glycol (TPG), poly(propylene glycol)-400, -725, -1200, -2000 + di-Me carbonate (DMC). From the experimetal data, excess enthalpies, HE, and std. deviations in enthalpy, s(HE) have been calcd. The exptl. data were fitted to a Redlich-Kister polynomial to obtain the binary adjustable parameters, ak. The HE values are pos. over the entire range of compn., decreasing with the increase of the mol. wt. of glycols. The mixts. contg. polydisperse glycols behave as regular solns. Conclusions were qual. discussed in terms of mol. interactions.