Chemistry

1996, No. 2

L.A. Onuchak, V.P. Garkin, E.L. Osipova, E.P. Sokolova

TERMODYNAMICS OF INTERMOLECULAR INTERACTIONS OF NONMESOMORPHIC COMPOUNDS WITH LIQUID CRYSTAL STATIONARY PHASES ON THE BASE OF PHENYLBENZOATE OF DIFFERENT POLARITY

The activity coefficients and excess partial molar enthalpy of mixing for nonmesomorphic organic compounds (n-alkanes C₅-C₉, n-alkanoles-1 C₂-C₅, benzene, m— and p—xylenes, tetrachlo- ride of carbon, pyridine, butanone-2, nitromethane) have been determined in two liquid crystals by gas-liquid chromatography. Phenylbenzoates, low-polar, 4-n-oktyloxyphenyl-4'-n-pentyloxybenzoate (nematic phase 51,0 - 81,5°C) and polar 4-nitrophenyl-4'-n-oktyloxybenzoate (smectic A-phase 49,2 - 62,0°C, nematic phase 62,0 - 68,2°C), were selected as liquid crystal stationary phases. The measurements have been carried out over a wide range of temperatures which are in agreement with stable states of isotropic, nematic and smectic phases. Obtained results have been considered on the basis of conception about nature and character of molecular interactions in liquid crystals with different polarity.