Manufacture of 4,4'-diphenylmethane diisocyanate and a mixture of diisocyanates and polyisocyanates
US4014914A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 25, 1974 |
| Grant date | Mar 29, 1977 |
| Priority date | — |
| Expiry date | Oct 25, 1994 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C263/10
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
Production of 4,4'-diphenylmethane diisocyanate and a mixture of diisocyanates and polyisocyanates by the phosgenation of pure 4,4'-diaminodiphenylmethane and a mixture of diamines and polyamines. 4,4'-Diaminodiphenylmethane is obtained by distillation of the mixture of products obtained from the reaction of aniline with formaldehyde and crystallization of the distillate from a solvent. The combined distillation residue and mother liquor from the crystallization form the mixture for reaction with phosgene to produce a mixture of diisocyanates and polyiisocyanates. This process produces a highly pure 4,4'-diphenylmethane diisocyanate which is particularly suitable for the production of polyurethanes serving as intermediates in the manufacture of rigid foams or as glue.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.