CRYOSCOPIC STUDIES OF PHOSPHORIC ESTERS AND THEIR MIXTURES IN CYCLOHEXANE

Dihexyl, didecyl phosphates and mixtures of dihexyl (A)-monohexyl (B) and didecyl (A)-monodecyl (B) phosphates having molecular ratio 1:1, 1:2 and 1:3 have been studied by cryoscopy in cyclohexane. Experimental results agree well with an association model in which the aggregates are in equilibrium with a basic unit which is a A2 form in the case of pure esters, or a (A(n)B(m))2 form in the case of mixtures (n and m are determined according to the proportions of di-mono esters in the starting mixture). This model has led to equilibrium constant values and to concentrations of the various entities.