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AssigneeCovestro Deutschland AG
InventorsJürgen Arras, Stefan Wershofen, Javier Pérez-Ramirez, Tobias Caesar Keller
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The invention relates to a production process for polyamines through condensation of aromatic amines with formaldehyde employing at least one solid zeolite catalyst partially or fully ion-exchanged to the protonic form which has been A) alkaline-treated, wherein the alkaline treatment is in case of BEA zeolites carried out in the presence of a pore-directing agent and in case of zeolites other than BEA zeolites in the presence or absence of a pore-directing agent, or B) acid-treated without any alkaline treatment preceding or following said acid treatment, wherein the acid treatment is effected with an organic acid with chelating function.
A process for the preparation of di- and polyamines of the diphenylmethane series comprising rearranging a condensation product, wherein said condensation product is formed by reacting aniline and a methylene group-supplying agent, and wherein said condensation product is reacted in the presence of at least one solid zeolite catalyst which is partially or fully ion-exchanged to the protonic form and comprises
The process according to 2, wherein said alkaline-treated zeolite catalyst A) comprises (ii) a BEA zeolite in which the alkaline treatment is carried out in a pH range of 10 to 15 using an alkali metal hydroxide solution at a temperature of from 10° C. to 100° C. for a period of from 0.1 minutes to 180 minutes with a zeolite loading of 5 g L−1 to 400 g L−1, in which “L” refers to the volume of the total reaction mixture.
Dependencies are inferred from the claim text.