Process for the manufacture of cyclosiloxanes by depolymerization of polysiloxanes
US5670689A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1996 |
| Grant date | Sep 23, 1997 |
| Priority date | — |
| Expiry date | May 10, 2016 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G77/045
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The present invention relates to a process for the manufacture of cyclic polydiorganosiloxanes, especially octamethylcyclotetrasiloxane (D.sub.4) and decamethylcyclopentasiloxane (D.sub.5) by depolymerization of polydiorganosiloxanes in the presence of an initiator, characterized in that the initiator comprises either: PA0 1) at least one hydroxide chosen especially from the group made up of caesium, rubidium or quaternary phosphonium hydroxides, or: PA0 2) the association of a fluorine-free caesium or rubidium salt, or of a salt of quaternary phosphoniums, with a hydroxyl-containing strong base of an alkali or alkaline-earth metal other than Cs and Rb.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.