Calorimetric measurements were carried out on ester-solvent systems where the esters were H(CH2)(x)COO(CH2)(y) H, with x and y varying from 1 to 5, and the solvents were n-hexane and 1,2-dichloroethane. Calculation of the enthalpies of cavity formation enabled the enthalpies of interaction to be determined. Both enthalpies correlated with number of carbon atoms N, equal to x+y in the esters, giving for 1,2-dichloroethane [GRAPHICS] From these linear correlations enthalpies of an aliphatic ester, for example, the enthalpy of vaporization can be calculated by using a thermochemical cycle. The presence of chloro atoms in the aliphatic solvent causes a large interactive effect between the ester and 1,2-dichloroethane.2413950