| US 7,498,399 B2 | ||
| Method of preparing ester-substituted diaryl carbonates | ||
| Paul William Buckley, Scotia, N.Y. (US); David Michael Dardaris, Ballston Spa, N.Y. (US); and Patrick Joseph McCloskey, Watervliet, N.Y. (US) | ||
| Assigned to Sabic Innovative Plastics IP B.V., Bergen op Zoom (Netherlands) | ||
| Filed on May 31, 2006, as Appl. No. 11/421,359. | ||
| Prior Publication US 2007/0282091 A1, Dec. 06, 2007 | ||
| Int. Cl. C08G 64/00 (2006.01); C08G 63/02 (2006.01) | ||
| U.S. Cl. 528—196 [264/176.1; 264/219; 422/131; 502/150; 502/208; 528/86; 528/198; 528/271; 528/272; 558/268; 558/274] | 22 Claims |
| 1. In a method of making an ester-substituted diaryl carbonate by reacting phosgene with a recycle stream of ester-substituted
phenol from a reaction process using a tetraalkyl phosphonium hydroxide, a tetraalkyl ammonium hydroxide, or both, as a catalyst,
the improvement comprising:
treating the recycle stream to reduce a catalyst degradation product concentration, if catalyst degradation product is present,
prior to the reaction with phosgene,
wherein the catalyst degradation product comprises a trialkyl phosphine, a trialkyl amine, or both, and
wherein at least one alkyl group of the tetraalkyl phosphonium hydroxide or the tetraalkyl ammonium hydroxide is a methyl
group.
|