Pressure-volume-temperature relations and isotropic-nematic phase transitions for 4-(trans-4-pentylcyclohexyl)benzonitrile.

Pressure-volume isotherms of 4-(trans-4-pentylcyclohexyl)benzonitrile were directly measured by means of piston-cylinder method at various temperatures. From the relation of the molar volume and the transition temperature which was determined by its clearing point, the parameter ∂lnTc⁄∂lnVc, was found to assume a value of −5.24, which should be closely related with the intermolecular potential energy. The value of this parameter increased correlatively with the alkyl chain length in the homologous series of 4-(trans-4-alkylcyclohexyl)benzonitriles.