Process for the preparation of oligocarbonates with two catalysts
US4005121A · kind A · utility
7Cited by
2References
9Claims
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Key dates
| Filing date | Dec 4, 1975 |
| Grant date | Jan 25, 1977 |
| Priority date | — |
| Expiry date | Dec 4, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G64/305
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for the preparation of linear aliphatic polycarbonates having terminal hydroxyl groups is carried out in two stages: I. in the first stage, the transesterification is carried out in the presence of a basic catalyst at a temperature below 140.degree. C, and Ii. in the second stage, after complete destruction of the basic catalyst, the transesterification is completed in the presence of an acid catalyst at a temperature of between 200.degree. and 250.degree. C. The polycarbonate-diols obtained are useful for the preparation of polyurethane elastomers which are resistant to hydrolysis.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.