EFFECT OF STRUCTURAL-CHANGES ON MESOPHASE STABILITY OF SOME MODEL COMPOUNDS BASED ON THE ARYL BENZOATE GROUP

Compounds based on 4,4'-substituted phenylbenzoate [RO-C6H4COO-C6H4-X] (I), where X is a cyano group and R is a terminal alkyl chain ranging from 12 to 30 carbon atoms, and alternatively where R is held at 16 c arbons and X is CN, COOH, OH, COOCH2C6H4 OCH2C6H4 and OC16H33, were pr epared and their mesophase stabilities characterized. Similarly, compo unds based on symmetric dimers of terminally alkoxy-substituted phenyl esters [C16H33O-C6H5COO-A-OOCC6H5-OC16H33] (II), the central linkage A being 1,2-, 1,3- and 1,4-phenylene, and 4,4'-biphenyl, were synthesi zed and studied. A partial success was achieved in the synthesis of co mpounds similar to series II, but where the ester groups were reversed (series III), in order to assess the influence of this structure vari ation on the liquid crystallinity.