Hydrolytic Polycondensation of Bisphenol-A-Bischloroformate Catalyzed by Phase-Transfer Catalysts
| Autor: | Claus-Ludolf Schultz, Sigrid Böhme, Hans R. Kricheldorf, Gert Schwarz |
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| Rok vydání: | 2003 |
| Předmět: |
Reaction mechanism
Polymers and Plastics Molecular mass Organic Chemistry Chloroformate Condensed Matter Physics Interfacial polymerization Catalysis chemistry.chemical_compound chemistry Bromide visual_art Polymer chemistry Materials Chemistry Mass spectrum visual_art.visual_art_medium Physical and Theoretical Chemistry Polycarbonate |
| Zdroj: | Macromolecular Chemistry and Physics. 204:1636-1642 |
| ISSN: | 1521-3935 1022-1352 |
| DOI: | 10.1002/macp.200350028 |
| Popis: | The hydrolytic interfacial polycondensation of bisphenol-A-bischloroformate was performed with four different phase-transfer (PT) catalysts: N-butylpyridinium bromide, triethylbenzylammonium (TEBA) chloride, tetrabutylammonium hydrogen sulfate, and tetraphenylphosphonium bromide. These polycondensations were conducted at 5 or 35°C initial reaction temperature. The resulting polycarbonates were characterized by viscosity and SEC measurements and by MALDI-TOF mass spectrometry. The four PTcatalysts gave quite different results with respect to molecular weight and formation of cyclic polycarbonates. The highest molecular weights (number average, M n 215 kDa and weight average, M w 600 kDa) were obtained with TEBA-X1. Lower temperatures and high feed ratios of TEBA-C1 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. |
| Databáze: | OpenAIRE |
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