Polymers of carbonic acid .22. Cholesteric polycarbonates derived from (S)-((2-Methylbutyl)thio)hydroquinone or isosorbide

(S)-((2-Methylbutyl)thio)hydroquinone was prepared from benzoquinone and (S)-2-methylbutyl mercaptan. One series of cholesteric copolycarbonates was prepared from this chiral hydroquinone, methylhydroquinone, and 4,4'-dihydroxybiphenyl by interfacial polycondensation with diphosgene. All copolycarbonates were noncrystalline and decomposed upon heating above 250 degrees C. A Grandjean texture was only observed for one sample. A second series of cholesteric copolycarbonates was prepared from isosorbide, methylhydroquinone, and 4,4'-dihydroxybiphenyl. Four different polycondensation methods were studied and compared in this case. The best results were obtained by polycondensation in pyridine containing organic cosolvents. Two copolycarbonates of isosorbide were obtained which formed a broad cholesteric phase with a Grandjean texture.