Abstract
Transition temperatures of quaternary mixtures prepared from the cyano and nitro derivatives of the two series, 4-hexadecyloxyphenyl 4-substituted benzoates (Ia,b) and 4-substituted phenyl 4-hexadecyloxy benzoates (IIa,b) have been determined by DSC and the transitions identified with polarized light microscopy. The cyano and nitro derivatives, in both series, were used because their molecules are enantiotropic. The method described before for the ternary system was extended to elucidate the eutectic composition of the quaternary system from the knowledge of either the eutectic compositions of the four possible ternary mixtures or of those of the six individual binary systems. A general equation was deduced to calculate the eutectic composition of any multi-component system from values determined for their individual binary systems. Tc values of binary, ternary, or quaternary mixtures were related to the polarizability anisotropy, DeltaalphaX, of the individual CAr-X bonds. The mixture law was successfully applied.