Oligomers bisphenol-A carbonate

Use of Gel Permeation Chromatography to Study the Synthesis of Bisphenol-A Carbonate Oligomers... 

A knowledge of the chemistry of bisphenol-A oligomer carbonate synthesis is useful in the interpretation of GPC data. Bisphenol-A carbonate oligomers can be prepared by reaction of bisphenol-A with phosgene in the presence of an acid acceptor. The reaction can be conducted interfacially (6), in homogeneous pyridine solution (7), or by merely passing phosgene into an alkaline solution of bisphenol-A (8). The chemical reactions that occur in each of these systems are complicated and consist of multiple and competitive reactions. 

The interfacial synthesis of bisphenol-A carbonate oligomers is conducted by passing phosgene into an agitated, two-phase mixture of a water-insoluble organic solvent and an alkaline solution of bisphenol-A. Reactions 1-4 shown on p. 260 illustrate some of the reactions believed to occur in the interfacial system. 

Interfacial Syntheses of Bisphenol-A Carbonate Oligomers. Oligomers that were prepared interfacially were made in a 5000-ml, three-necked-baffled flask equipped with a water condenser and a Dry Ice condenser. Cooling was provided by an ice bath around the reactor. 

Syntheses of Bisphenol-A Carbonate Oligomers in Aqueous Caustic. Oligomers made by the aqueous caustic method were made in an apparatus identical with that used in the interfacial method experimental conditions were similar. Methylene chloride, though, was not added to the reaction mixture. The product precipitated on formation and was isolated by filtration. 

Syntheses of Bisphenol-A Carbonate Oligomers in Homogeneous Pyridine. Oligomers made by the pyridine method were prepared in the same apparatus except that drying tubes were added where necessary. It was also necessary to use carefully dried solvents since the undesirable side reaction with water converts chlorocarbonic acid to hydrochloric acid and carbon dioxide, thus upsetting the reaction stoichiometry. 

Analysis of Bisphenol-A Carbonate Oligomers for Phenolic Hydroxyl. 

Analysis of Bisphenol-A Carbonate Oligomers for Chloroformate Chlorine. Chloroformate chlorine end groups were determined by a modified Volhard procedure in which the bischloroformate first reacts with aqueous pyridine to convert chloroformate to chloride ion. The chloride ion is extracted into water and titrated by the Volhard procedure. 

Table III. CPC Data on Bisphenol-A Carbonate Oligomers Prepared in Pyridine...

Positive ions FAB-MS spectra of poly(bisphenol-A carbonate) oligomers obtained by (a) synthesis and (b) by methanolysis of high molar mass poly(bisphenol-A carbonate). (Reprinted with permission from Ref. 29.)... 

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