화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.605, No.1, 61-69, 2014
Synthesis and Liquid Crystal Properties of a Novel Homologous Series 4-(4'-n-Alkoxy benzoyloxy) Benzyl Benzoates
A novel homologous series consisting of 11 homologues is reported. Liquid crystal properties commence from the hexyloxy homologue and continue up to the tetradecyloxy homologue as enantiotropic nematic mesomorphism only. The rest of the homologues (including hexadecyloxy homologue) are not liquid crystalline. None of the homologues show smectogenic mesophase formation. The texture of the nematic mesophase is of a threaded or Schlieren type. The transition temperatures of the homologues were determined by optical polarizing microscopy equipped with a heating stage. Transition curves of a phase diagram behave in normal manner except for the tetradecyloxy homologue which adopts an unexpected trend of propagation. An odd-even effect is absent for nematic-isotropic transition curve. Analytical and spectral data support the molecular structure of the homologues. The average thermal stability of the series is 78.8 degrees C. Mesomorphic/nematogenic phase length varies from 2.0 degrees C to 13.0 degrees C. The liquid crystal behavior of the present series is compared with structurally similar other known series. Thus, the present series is enantiotropically nematogenic only without exhibition of any smectogenic character with a low melting type, whose mesomorphic phase length is relatively short.