Salts of organic phosphates as catalysts for melt polycarbonate
US6583258B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 2001 |
| Grant date | Jun 24, 2003 |
| Priority date | — |
| Expiry date | Oct 25, 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 in which one or more diaryl carbonates is reacted 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 phosphates in combination with tetraalkylammonium or tetraalkylphosphonium compounds which serve as co-catalysts. The organic phosphate derivative adenosine 5′-monophosphate disodium salt was shown to possess excellent activity as a transesterifcation catalyst for the preparation of polycarbonate under melt polymerization conditions. The catalysts employed according to the method of the present invention provide polycarbonates having substantial molecular weight (Mn˜8000-10000 daltons) and reduced levels of Fries rearrangement product relative to conventionally prepared melt polycarbonate having a similar molecular weight.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.