Method for preparing isophorone diisocyanate
US11939280B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 25, 2018 |
| Grant date | Mar 26, 2024 |
| Priority date | — |
| Expiry date | Dec 7, 2039 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C2601/16
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A method for preparing isophorone diisocyanate by (1) reacting isophorone with hydrogen cyanide in the presence of a catalyst to obtain isophorone nitrile; (2) reacting the isophorone nitrile obtained in step (1) with ammonia gas and hydrogen in the presence of a catalyst to obtain isophorone diamine; and (3) subjecting the isophorone diamine to a phosgenation reaction to obtain the isophorone diisocyanate, wherein the content of impurities containing a secondary amine group in the isophorone diamine that undergoes the phosgenation reaction in step (3) is ≤0.5 wt. The method reduces the content of hydrolyzed chlorine in the isophorone diisocyanate product, improves the yellowing resistance of the product, and the harm due to presence of hydrolyzed chlorine in the product is reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.