Method for preparing diamino-dicyclohexyl methane
US9580380B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 22, 2013 |
| Grant date | Feb 28, 2017 |
| Priority date | — |
| Expiry date | Nov 22, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02P20/584
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
Disclosed is a method for preparing diamino-dicyclohexyl methane (H12MDA) by hydrogenation of diamino-diphenyl methane (MDA). In the process, 4,4′-MDA used as the starting material is firstly hydrogenated to prepare 4,4′-H12MDA. When the activity of the catalyst is reduced, the feed is switched from 4,4′-MDA to the mixture of 2,4′-MDA and 4,4′-MDA, and then when the conversion is stabilized, the feed is switched to 4,4′-MDA again. The deactivated catalyst is activated on line by switching the feed to the mixture of 2,4′-MDA and 4,4′-MDA. 4,4′-H12MDA having the trans-trans isomer content of 16˜24 wt % is produced, and the mixture of 2,4′-H12MDA and 4,4′-H12MDA is also produced, wherein the content of 2,4′-H12MDA in the mixture is 4˜15 wt %.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.