Process for the preparation of polyamines of the diphenylmethane series at a low degree of protonation
First Claim
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1. A process for the acid-catalysed preparation of polyamines of the diphenylmethane series, comprisinga) reacting aniline and formaldehyde in a molar ratio of 1.5:
- 1 to 6;
1 at temperatures of 20°
C. to 100°
C., in which the water content in the acid reaction mixture is <
20 wt. % and a degree of protonation of <
15% is established, andb) increasing the temperature of the reaction to 110°
C. to 250°
C. when the ratio of the weight contents of p-aminobenzylaniline to 4,4′
-MDA in the acid reaction mixture falls below a value of 1.00.
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Abstract
The invention provides a process for the preparation of polyamines of the diphenylmethane series. This process comprises
- a) reacting aniline and formaldehyde in a molar ratio of 1.5:1 to 6:1, in the presence of an acid catalyst at temperatures of 20° C. to 100° C., in which the water content in the acid reaction mixture is <20 wt. % and a degree of protonation of <15% is established, and
- b) increasing the temperature of the reaction to a temperature of 110° C. to 250° C. when the ratio of the weight contents of p-aminobenzylaniline to 4,4′-MDA in the reaction mixture falls below a value of 1.00.
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9 Claims
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1. A process for the acid-catalysed preparation of polyamines of the diphenylmethane series, comprising
a) reacting aniline and formaldehyde in a molar ratio of 1.5: - 1 to 6;
1 at temperatures of 20°
C. to 100°
C., in which the water content in the acid reaction mixture is <
20 wt. % and a degree of protonation of <
15% is established, andb) increasing the temperature of the reaction to 110°
C. to 250°
C. when the ratio of the weight contents of p-aminobenzylaniline to 4,4′
-MDA in the acid reaction mixture falls below a value of 1.00. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
- 1 to 6;
Specification