Abstract: The invention relates to a production process for di- and polyamines of the diphenylmethane series by the rearrangement of a condensation product of aniline and a methylene group-supplying agent preferably selected from the group consisting of aqueous formaldehyde solution, gaseous formaldehyde, para-formaldehyde, trioxane and mixtures thereof, wherein said condensation product is reacted in the presence of at least one silica-alumina catalyst, said catalyst having a surface area as determined by the BET method carried out according to ASTM D3663-03 (2015) of from 200 m2/g to 520 m2/g, preferably of from 350 m2/g to 495 m2/g, particularly preferably of from 400 m2/g to 490 m2/g, a molar ratio of silica/alumina on the catalyst surface of A, an overall (bulk) molar ratio of silica/alumina of C, and a quotient B=A/C; said catalyst being characterised in that “low” A values (i.e. equal to or lower than 8.0) are combined with “high” B values (i.e. of from 1.50 to 3.00), and “high” A values (i.e. larger than 8.

Abstract: 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.

Abstract: The invention relates to a production process for di- and polyamines of the diphenylmethane series by the rearrangement of a condensation product of aniline and a methylene group-supplying agent preferably selected from the group consisting of aqueous formaldehyde solution, gaseous formaldehyde, para-formaldehyde, trioxane and mixtures thereof, wherein said condensation product is reacted in the presence of at least one silica-alumina catalyst, said catalyst having a surface area as determined by the BET method carried out according to ASTM D3663-03 (2015) of from 200 m2/g to 520 m2/g, preferably of from 350 m2/g to 495 m2/g, particularly preferably of from 400 m2/g to 490 m2/g, a molar ratio of silica/alumina on the catalyst surface of A, an overall (bulk) molar ratio of silica/alumina of C, and a quotient B=A/C; said catalyst being characterised in that “low” A values (i.e. equal to or lower than 8.0) are combined with “high” B values (i.e. of from 1.50 to 3.00), and “high” A values (i.e. larger than 8.

Abstract: 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.