Azonaphthalene sulfonates as polymerization catalysts
US6639043B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 27, 2002 |
| Grant date | Oct 28, 2003 |
| Priority date | — |
| Expiry date | Jun 27, 2022 |
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 azonaphthalene sulfonates in combination with tetraalkylammonium or tetraalkylphosphonium compounds which serve as co-catalysts. The transesterification 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 in combination with tetramethylammonium hydroxide co-catalyst.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.