Synthesis and miscibility studies of some phenyl cinnamoyloxybenzoate derivatives

Abstract

Some members of the homologous series, 4-cyanophenyl-3'-methyl-4'(4"-n-alkyloxycinnamoyloxy) benzoate and 4-cyanophenyl-3'-methyl-4'(4"-n-alkyloxy-agr-methyl cinnamoyloxy)benzoate have been prepared. The transitions were studied by hot stage microscopy and differential scanning calorimetry. The undecyloxy- and dodecyloxy-derivatives exhibit a reentrant nematic phase at atmospheric pressure. The effect of a lateral substituent on the reentrant phenomenon in these compounds is discussed.

A detailed study of the phase diagrams of binary mixtures of each of these compounds exhibiting a reentrant phase with 4-cyanophenyl-3'-methyl-4'(4"-n-decylbenzoyloxy)benzoate, a compound exhibiting no reentrant phase has been carried out. Interestingly, in three cases, the binary mixtures exhibit stable enantiotropic reentrant behaviour over a range of composition though the pure compounds themselves are monotropic reentrants.