SYNTHESIS OF POLY(MONOCYCLIC ORTHOCARBONATE)S BY POLYCONDENSATION WITH SILYLATED DIPHENOLS

Various poly(monocyclic orthocarbonate)s were synthesized by the polycondensation of 2,2-dichloro-1,3-benzodioxide (1) with a variety of silylated diphenols and their properties were examined. Polycondensation of 1 with silylated Bisphenol A (2) in bulk at room temperature proceeded under the catalysis of HCI or Bu4NF to give high yields of the corresponding poly(monocyclic orthocarbonate) (I 0) but was very slow with catalysts such as Me3SiCl, BF3OEt2, and CsF or without catalyst. In bulk poly condensation, 10(M(n)BAR = 29100) was obtained quantitatively when Bisphenol A (BPA) was used as catalyst, where a quantitative amount of Me3SiCl was recovered as a by product. Solution polycondensation in chlorobenzene also proceeded efficiently at 60-degrees-C to give 10 (M(n)BAR = 32400) in 95 % yield. The mechanism of the polycondensation is discussed. Several poly(monocyclic orthocarbonate)s were prepared in quantitative yield by the polycondensation of 1 with the corresponding silylated diphenols in the presence of BPA in chlorobenzene at 60-degrees-C. Polycondensation of 1 with silylated alkyl diols afforded no corresponding poly(monocyclic orthocarbonate)s but instead complex mixtures including polymers having linear carbonate and/or ether functions. A little higher yield of 10 was attained in the polycondensation with an excess amount of 1. The molecular weight of 10 could be controlled by changing the amount of 4-tert-butylphenol instead of BPA to serve as both catalyst and terminator. The glass transition temperatures (T(g)) of the polymers were in the range from 88 to 136-degrees-C and were compared with those of the polymers derived from nonsilylated diphenols. The polymers lost 10% of their weights at temperatures ranging from 300 to 345-degrees-C depending on their structures.