Heats of mixing of Dichloroethan with Non-polar Liquids

For three solution of dichloroethane which is regarded as a typical molecule having internal rotation isomers, the excessive enthalpies arising from the internal reaction were calculated according to a simple theory derived from the Onsager model, and were compared with the result obtained from the measurements of heats of mixing for these solutions. The agreement was not very good and it seems to owe to the overestimation of the reaction field based on the simple molecular modern in the Onsager model. Especially for the dichloroethane-benzene system, special interactions may be expected to exist between dichloroethan and benzene.