Process for preparing high trans, trans-isomer containing 4,4'-diisocyanato dicyclohexylmethane
US4983763A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 1990 |
| Grant date | Jan 8, 1991 |
| Priority date | — |
| Expiry date | Apr 19, 2010 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C263/20
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
The present invention is directed to a simple process for preparing a 4,4'-diisocyanato dicyclohexylmethane containing at least 90% by weight of the trans, trans-isomer. More particularly, the process comprises: PA0 (a) melting a mixture of 4,4'-diisocyanato dicyclohexylmethane isomers containing at least 30% by weight, and preferably from 45 to 55% by weight, of the trans,trans-isomer, PA0 (b) cooling the melted mixture to a temperature of from about 20.degree. to about 25.degree. C. to form; PA1 (1) a liquid phase which contains from about 18 to about 25% by weight of the trans,trans-isomer, and PA1 (2) a solid phase which contains from about 70 to about 85% by weight of the trans,trans-isomer, PA0 (c) removing said liquid phase, PA0 (d) dissolving said solid phase in a solvent to form a 4,4'-diisocyanato dicyclohexylmethane-containing solution, PA0 (e) allowing said solution to remain at room temperature for a time sufficient to form: PA1 (1) a solid phase containing at least 90% by weight, and preferably at least 98% by weight of the trans,trans-isomer, and PA1 (2) a liquid phase containing said solvent and a mixture of 4,4'-diisocyanato dicyclohexylmethane isomers containing f…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.