Process for the purification of MDA
US4028361A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 1975 |
| Grant date | Jun 7, 1977 |
| Priority date | — |
| Expiry date | Aug 18, 1995 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC07C209/00
- WIPO fieldOrganic fine chemistry
- WIPO sectorChemistry
Abstract
A process is described for the selective removal of 2,2'- and 2,4'-diaminodiphenylmethane from mixtures thereof with the corresponding 4,4'-isomer by heating the mixture of isomers in the presence of a 1,3,5-tri-arylhexahydro-1,3,5-triazine and a catalyst (aqueous mineral acid). The process is particularly useful in facilitating the isolation of substantially pure 4,4'-isomer from the aniline-formaldehyde condensation. The pure 4,4'-isomer is a valuable intermediate for polyamides as well as for the corresponding diisocyanate. The by-products of the reaction are oligomeric polymethylene polyphenyl polyamines which are also useful as curing agents and intermediates for polymethylene polyphenyl polyisocyanates and the like.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.