Study of the Liquid Crystalline Phases in Some Compounds of4-Trans-(4-Alkyl)Cyclo-Hexylphenyl-Alkylcarboxylate

C 3 H 7 , R2 = C 3 H 7 ) , H34(R! = C 3 H 7 , R2 = C 4 H 9 ) and H75(R, = C7H15, R2 = C 5 H„) have been investigated by differential scanning calorimetry. thermal optical microscopy and X-ray diffraction methods/Enthalpy changes of The different phase transitions for these compounds have been determined. H33 exhibits smectic B and nematic phases, whereas H34 and H75 exhibit only smectic B phases. The thickness of the smectic layers and the average intermolecular distance have been evaluated, as well as the corresponding molecular parameters in the nematic phase.