METHOD FOR PRODUCING METHYLENED DIPHENYLDIAMINE USING A HETEROGENEOUS CATALYST Russian patent published in 2021 - IPC C07C209/78 C07C211/51 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for producing a product with a total content of methylenediphenyldiamine of at least 94% with a predominant content of the target 4,4'-methylenediphenyldiamine and a content of non-target 2,4-, 2,2'-methylenediphenyldiamine of less than 10 and 3 mass%, respectively, which can find application in the manufacture of varnishes, adhesives, synthetic leather and synthetic rubber. The method includes a stage of condensation of formaldehyde and excess aniline and two stages of isomerization of the resulting product on an ion-exchange resin based on a copolymer of divinylbenzene with styrene and propylene polymers. Precondensate is obtained by the interaction of aniline and formaldehyde in the presence of aluminum oxide (III) in an amount from 1*10^-3 to 8*10^-3 mol per 1 mol of aniline at a temperature of 50-80°С. The first stage of isomerization is carried out at a temperature of 100°C and the second stage of isomerization is carried out at a temperature of 120°C.

EFFECT: increased service life of the heterogeneous catalyst.

1 cl, 4 dwg