Hydrolytic polycondensation of bisphenol-A-bischloroformate catalyzed by phase-transfer catalysts

摘要

The hydrolytic interfacial polycondensation of bisphenol-A-bischloroformate was performed with four different phase-transfer (PT) catalysts: N-butylpyridinium bromide, triethylbenzylammonium (TEBA) chloride, tetra-butylammonium hydrogen sulfate, and tetraphenylphosphonium bromide. These polycondensations were conducted at 5 or 25degreesC initial reaction temperature. The resulting poly-carbonates were characterized by viscosity and SEC measurements and by MALDI-TOF mass spectrometry. The four PT catalysts gave quite different results with respect to molecular weights (number average, (M) over bar (n) approximate to 215 kDa and weight average, (M) over bar (W) approximate to 600 kDa) were obtained with TEBA-Cl proved to be favorable for both high molecular weights and high fractions of cycles. Cyclic polycarbonates were detectable in the mass spectra up to 14 kDa (technical limit of the measurements). Low molecular weights in combination with unreacted chloroformate groups proved that the other PT-catalysts were less efficient under the given reaction conditions. [References: 22]