Heat of solution in water of the liquid methylene group at 25°C

Abstract

The heats of solution of some liquid n-carboxylic acids and n-alkanols to high dilution in water at 25°C have been determined calorimetrically. From these and already published data, for a series of n-alkylhexaoxyethylene glycol monoethers, it is concluded that the heat of solution of the liquid —CH₂— group in water for the systems studied is about +350 cal/mole up to alkyl chain lengths of C₈, if polar head group effects are not operative. There is no evidence that above C₈ the —CH₂— increment in the heat of solution of n-alkyl chain compounds is constant. The usefulness of alkane/water interfacial tension data in estimating the thermodynamic parameters of transfer of the methylene group is discussed.