Loading patent…
AssigneeDegussa AG
InventorsBernd Jaeger, Thomas Haas, Guido Stochniol, Christian Lettmann, Willi Hofen, Klaus Stadtmueller, Joerg Lotz
Estimating the term…
The invention relates to a process for increasing the selectivity of the hydrogenation of 4,4′-diaminodiphenylmethane (4,4′-MDA) to diaminodicyclohexylmethane (4,4′-HMDA) by catalytic hydrogenation of a mixture containing 4,4′-MDA as the main component and its mono-N-methyl derivative as a secondary component. According to the invention, the hydrogenation is terminated before a conversion of 4,4′-MDA to 4,4′-HMDA of 99% is achieved. Under these conditions, a substantially smaller proportion of the N-methyl-4,4′-MDA is hydrogenated to N-methyl-4,4-HMDA.
A process for the production of 4,4′-diaminodicyclohexylmethane (4,4′-HMDA) by catalytic hydrogenation of a mixture comprising 4,4′-diaminodiphenylmethane (4,4′-MDA) as the main component and a mono-N-methyl derivative thereof as a secondary component with increased selectivity with regard to the hydrogenation of 4,4′-MDA in the presence of a heterogeneous hydrogenation catalyst at a temperature in the range of 50 to 220° C. and a hydrogen pressure in the range of 1 to 30 MPa,
Dependencies are inferred from the claim text.