Siloxane bischloroformates
US6723864B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 16, 2002 |
| Grant date | Apr 20, 2004 |
| Priority date | — |
| Expiry date | Oct 16, 2022 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/24
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Siloxane bischloroformates are prepared in a continuous process by phosgenating siloxane bisphenols in a flow reactor using a substantial excess of phosgene and sodium hydroxide. While very high levels (>95%) of conversion of the siloxane bisphenol to the corresponding siloxane bischloroformate are achieved using a flow reactor according to the method of the invention, only more modest conversion (˜90%) of the siloxane bisphenol to the corresponding siloxane bischloroformate is attained when analogous batch processes are employed. The process holds promise for use in the manufacture of silicone-containing copolycarbonates which requires high purity siloxane bischloroformate intermediates.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.