Density, Refractive Index and Ultrasonic Velocity Studies Involving N-(p-n-Pentyloxybenzylidene)-p-n-octylaniline

Abstract

The density, refractive index and ultrasonic velocity dependence on temperature for N-(p-npentyloxybenzylidene)- p-n-octylaniline, 50.8, is presented. The compound 50.8 exhibits smectic-B, smectic-A and nematic phases between the solid and isotropic liquid phases. The nematic-isotropic and smectic A-smectic B phase transformations are found to be first order. The interesting smectic A - nematic transformation is confirmed from the results to be second order, although the thermal expansion coefficient and reported enthalpy data had suggested a weak first order transition. The computed adiabatic compressibility, β ad , molar sound velocity, R n , and molar compressibility A w are presented.