Process for preparing MDA via the stage of the aminal
AssigneeBASF SE
InventorsEckhard Stroefer, Kai Thiele, Michael Zoellinger, Johnny Moors, Jon S. Speier
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Abstract
The invention relates to a process for preparing methylenediphenyldiamine (MDA), comprising the following steps a) to c): a) converting formaldehyde and aniline to aminal b) removing water from the aminal obtained in step a) to establish a water content of 0 to 5% by weight based on the aminal, and c) adding an acidic catalyst to the aminal having a water content of 0 to 5% by weight, which comprises using formaldehyde in step a) in the form of highly concentrated formaldehyde with a CH2O content of >50% by weight and preparing the formaldehyde by oxidative dehydrogenation from methanol.
Claims15
A process for preparing methylenediphenyldiamine (MDA), the process comprising:
- (a) converting formaldehyde and aniline to an aminal;
- (b) removing water from the aminal obtained in (a) to establish a water content of 0 to 5% by weight, based on the aminal;
- and
- (c) adding an acidic catalyst to the aminal having a water content of 0 to 5% by weight,
- wherein the formaldehyde in (a) is in the form of a first formaldehyde solution with a CH2O content of >50% by weight and is prepared by oxidative dehydrogenation from methanol.
Dependencies are inferred from the claim text.