THERMODYNAMICS OF BINARY-MIXTURES OF ALKYLBENZENES - ROLE OF ORIENTATIONAL ORDER IN BENZENE PLUS ALKYLBENZENE MIXTURES

The results of measurements for excess molar enthalpies, excess molar heat capacities and excess molar volumes of a number of mixtures consi sting of alkylbenzenes reported from our laboratories and the literatu re data on similar systems have been examined here. It has been noted that the behavoiur of mixtures containing benzene + alkylbenzene is qu ite different from those mixtures in which both the components are alk ylbenzenes. These observations have been explained in terms of importa nce of orientational order present in pure benzene. In general the exc ess functions depend on the difference (n2 - n1) in the chain lengths of alkyl groups of the two components.