Process for the preparation of diamines and polyamines of the diphenylmethane series

By optimizing the mixing characteristic parameter M of the pre-reaction liquid, the problems of N-methyl impurities and macromolecular polymers caused by uneven mixing of aniline and formaldehyde were solved, achieving high quality of DAM products and long-term stable operation of the equipment.

CN117865817BActive Publication Date: 2026-07-10WANHUA CHEM GRP CO LTD
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
WANHUA CHEM GRP CO LTD
Filing Date
2023-12-26
Publication Date
2026-07-10

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Abstract

The application belongs to the technical field of diamine and polyamine of diphenylmethane series, and particularly relates to a preparation method of diamine and polyamine (DAM) of diphenylmethane series, that is, before a condensation reaction, a mixing characteristic parameter 1.0<=M<=1.5 of a pre-reaction liquid for the condensation reaction is controlled; the pre-reaction liquid is a mixed liquid formed after a mixture of a formaldehyde solution and aniline hydrochloride or a mixture of the formaldehyde solution and aniline hydrochloride / condensation reaction liquid is pre-mixed. In the method, the mixing characteristic parameter M is controlled in a suitable range, so that the content of N-methyl impurities and the content of macromolecular polymers in the DAM product can be maximally reduced, and the running stability of a production device and the quality of downstream products can be improved.
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Citation Information

Patent Citations

  • continuous process for the production of methylene bridge-containing polyphenylpolyamines which have a high content of 4,4'-isomers of di(aminophenyl)methane

    DE2049707A1

  • Process for preparing MDA via the stage of the aminal

    US8710267B2

  • High-shear mixing reactor and preparation method of diphenylmethane series amine

    CN115634655A