Abstract: The present invention relates to a method of neutralizing residual acid species in crude dihydric phenol comprising the step of introducing a thermally stable organic base selected from the group consisting of tetraalkyl phosphonium hydroxides, tetraorganophosphonium carboxylic acid salts, or a mixture thereof into the crude dihydric phenol.

Abstract: High yields of ester-substituted diary carbonates such as bis-methyl salicyl carbonate were obtained by the condensation of methyl salicylate with phosgene in the presence of a phase transfer catalyst (PTC) in an interfacial reaction system in which the pH of the aqueous phase was greater than 9.3. Using the method of the present invention conversions of greater than 99% were obtained whereas under standard conditions using triethylamine as the catalyst conversions were limited to 70-75% of the methyl salicylate starting material even with a 20 mole % excess of added phosgene. The optimized conditions of the of the present invention use only a slight excess of phosgene and represent an attractive route for the manufacture of bis methyl salicyl carbonate and ester-substituted diaryl carbonates generally.

Abstract: Extrusion of a mixture of an ester-substituted diaryl carbonate, such as bis-methyl salicyl carbonate, a dihydroxy aromatic compound such as bisphenol A and a transesterification catalyst such as tetrabutyl phosphonium acetate (TBPA) affords polycarbonate having a weight average molecular weight of greater than 20,000 Daltons. The extruder is equipped with one or more vacuum vents to remove by-product ester-substituted phenol. Similarly, a precursor polycarbonate having ester-substituted phenoxy endgroups, for example methyl salicyl endgroups, when subjected to extrusion affords a polycarbonate having a significantly increased molecular weight relative to the precursor polycarbonate. The reaction to form a higher molecular weight polycarbonate may be catalyzed by residual transesterification catalyst present in the precursor polycarbonate, or by a combination of any residual catalyst and an additional catalyst such as TBPA introduced in the extrusion step.

Abstract: The present invention relates to a method of neutralizing residual acid species in crude dihydric phenol comprising the step of introducing a thermally stable organic base selected from the group consisting of tetraalkyl phosphonium hydroxides, tetraorganophosphonium carboxylic acid salts, or a mixture thereof into the crude dihydric phenol.

Abstract: Acidic impurities in dihydroxyaromatic compounds such as bisphenol A, as illustrated by sulfonic acids and mercaptocarboxylic acids, can have an adverse effect on the molecular weight of a polycarbonate prepared therefrom by transesterification. The same is true of acidic impurities in diaryl carbonates such as diphenyl carbonate, as illustrated by salicylic acid and ferric chloride. The reagents are analyzed for these impurities. Based on the analysis, the reagents are discarded or recycled, or a compensatory amount of alkali metal hydroxide is employed as a catalyst in the reaction.

Abstract: This invention relates to a method for the preparation of polycarbonate by the melt process comprising reacting a diphenol and a diarylcarbonate in the presence of a catalyst system comprising a catalytically effective amount of an alkali and/or alkali earth metal salt of a non volatile acid and a base.

Abstract: This invention relates to mixed dialkali metal salts of sulfuric acid containing at least one cesium equivalent useful in catalyst systems in melt polymerizations. The catalysts provide product with low branching side reaction products and good properties.

Abstract: The present invention relates to a method for the preparation of polycarbonate comprising preparing a polycarbonate by a melt process by reacting a diphenol and a diaryl carbonate in the presence of a catalytically effective amount of one or more alkali and or alkali earth metal salts of chelating agents. Suitable chelating agents include nitrilotriacetate and EDTA.

Abstract: A melt condensation polymerization process for preparing siloxane copolycarbonates is provided. The process includes reacting an aromatic dihydroxy compound, carbonic acid diester, hydroxyaryl terminated polydiorganosiloxane and catalyst with a salt.

Abstract: A method of preparing polycarbonate by the melt process comprising the steps of: a) melting a dihydric phenol and a diester of carbonic acid for a time and at a temperature sufficient to form a melt; and thereafter introducing a catalyst composition comprising a tetraorganophosphonium salt or a derivative thereof and 1) an alkali and/or alkali earth metal compound or derivative thereof or 2) a less active alkali and/or alkali earth metal derivative thereof into the melt; and b) oligomerizing the product from step a) to a number average molecular weight of from about 3000 to about 7500; and c) polymerizing the product from step b) to a number average molecular weight of from about 16,000 to about 35,000.

Abstract: The present invention relates to a method for the preparation of polycarbonate comprising preparing a polycarbonate by a melt process by reacting a diphenol and a diaryl carbonate in the presence of a catalytically effective amount of one or more alkali metal salts of oxoacids of sulfur.

Abstract: This invention relates to salts of aryl sulfonic acids useful in catalyst systems in melt polymerizations. Suitable alkali metal salts of aryl sulfonic acids include alkali metal salts of p-toluenesulfonic acid. The invention further relates to polycarbonates prepared using the catalyst systems of the present invention, and articles made from these polycarbonates.