Synthesis and Properties of High-Temperature Mesomorphic Polysiloxane Solvents: Biphenyl- and Terphenyl-Based Nematic Systems

Article abstract of DOI:10.1021/ac00280a019

The synthesis and characterization of a variety of mesomorphic (liquid-crystalline) side-chain polysiloxane (MEPSIL) solvents, said to be useful as gas chromatographic stationary phases, are described and discussed.The synthetic scheme is based upon the hydrosilation reaction that occurs when 4-(allyloxy)benzoyl esters are contacted with poly(methylsiloxane) in the presence of a dicyclopentadienylplatinum(II) catalyst, while product characterization is carried out by IR, NMR, GC, DSC, elemental analysis, and direct-observation hot-stage light-polarized microscopy.Selectivity of the MEPSIL phases is shown to differ very substantially from those exhibited by all other common GC solvents.The MEPSIL found overall to be the best suited as a GC stationary liquid exhibits a melting point of 139 deg C (k -> n) and a nematic/isotropic (n -> i) transition temperature of 319 deg C, while the practical operating limits of the material span 150 to in excess of 300 deg C.