Salts of organic polyacids as polymerization catalysts
US6569986B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 2001 |
| Grant date | May 27, 2003 |
| Priority date | — |
| Expiry date | Dec 11, 2021 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/307
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
The present invention relates to a synthetic method comprising contacting at least one diaryl carbonate with one or more dihydroxy aromatic compounds in the presence of a transesterification catalyst under melt polymerization conditions to afford a product polycarbonate. The transesterifcation catalysts used according to the method of the present invention are alkali metal salts and alkaline earth metal salts of organic polyacids in combination with tetraalkyl ammonium or tetraalkyl phosphonium compounds which serve as co-catalysts. The transesterification catalysts are derived from polyacids containing both CO2H groups and SO3H groups and from polyacids containing exclusively CO2H groups or exclusively SO3H groups. The catalysts employed according to the method of the present invention provide polycarbonates having reduced levels of Fries rearrangement product relative to conventionally employed catalysts such as sodium hydroxide.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.