Production of 2,6-toluylene diisocyanate from a mixture comprising 2,6-toluylene diisocyanate and 2,4-toluylene diisocyanate
US5783727A · kind A · utility
2Cited by
2References
18Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jan 21, 1997 |
| Grant date | Jul 21, 1998 |
| Priority date | — |
| Expiry date | Jan 21, 2017 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C263/20
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for obtaining substantially pure toluylene 2,6-diisocyanate from a mixture of the 2,4 and 2,6 isomers of toluylene diisocyanate, wherein at least one crystallizing-melting cycle is performed on the mixture of said isomers to separate out the toluylene 2,6 diisocyanate isomer. In an alternative embodiment, the mixture is contacted, prior to the crystallizing-melting cycle, with a compound or catalyst capable of converting part of the toluene 2,4-diisocyanate isomer therein, and the reacted 2,4 isomer is separated. Said method is advantageous in that usable by-products are produced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.