DE1210872B - Process for the preparation of 4,4'-diaminodiphenylmethanes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. CL:

Number:
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C 07 c

German KL: 12 q- 1/02

1210 872
B73684IVb / 12q
September 28, 1963
17th February 1966

Subject of patent application B 69931 IVb / 12q is a process for the preparation of 4,4'-diaminodiphenylmethanes the general formula

R ₃

wherein Ri, R2 and R3 are hydrogen atoms or the same or various alkyl, aryl or cycloalkyl radicals which can also carry further substituents, R2 and R3 also denotes alkoxy groups or halogen atoms, by reacting in the p-position unsubstituted aromatic amines of the general formula

R ₂

R ₃

wherein have Ri, R2 and R3 have the previously mentioned meaning, with formaldehyde or under the reaction conditions such as formaldehyde reacting substances in the presence of acids at temperatures between 70 and 15O ⁰ C, which is characterized in that the reaction in the presence of catalytic amounts of acids , which are present in the heterogeneous phase during the conversion.

It has been found that in this process the life of the catalysts is still extended Can be increased significantly if the reaction is carried out with the exclusion of oxygen or oxygen-containing substances Performs gases.

The starting materials and the reaction conditions correspond to those of the process according to Patent application B 69931 IVb / 12q.

When carrying out the process, an oxygen-free, inert gas, ζ. B. nitrogen or argon, passed. Any oxygen dissolved in the starting materials can be z. B. easily removed by heating to temperatures between 80 and 120 ⁰ C or by passing nitrogen through.

The process can be carried out continuously or discontinuously.

One advantage that can be achieved in working according to the invention is a demand 5c increase the service life of the catalytic converters by 30 to 50%. Furthermore, almost colorless di-

Process for the production of
4,4'-diaminodiphenylmethanes

Addition to registration: B 69931IV b / 12 q Auslegeschrift 1179 945

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Helmut Schmidt, Ludwigshafen / Rhine;

Dr. Rolf Platz, Mannheim;

Dr. Hugo Kröper, Heidelberg

aminodiphenylmethanes, which can be further processed without intermediate purification.

The parts given in the examples are parts by weight.

example 1

700 parts of aniline, 100 parts of a polymerization product obtained by polymerization and subsequent sulfonation from styrene, divinylbenzene and sulfuric acid, and 164 parts of 37% aqueous formaldehyde solution are placed in a stirrer-equipped reaction vessel with a distillation bridge from which all oxygen is displaced with nitrogen is, mixed, heated to 110 ° C and the water present is distilled off. After stirring for 20 hours under a nitrogen atmosphere at 110 ⁰ C is filtered off from the catalyst and distilling the light yellow colored solution. 295 parts of 4,4'-diaminodiphenylmethane distill over at 210 to 215 ° C. at 4 torr. The yield is 85% of theory, based on converted aniline.

The filtered off, still aniline-moist catalyst is in a nitrogen atmosphere until the next batch kept. The catalyst thus retains its good effectiveness for 600 hours. You work in the present of oxygen, the life of the catalyst is only 400 hours.

609 508/238

Example 2

A heated steel tube, which contains 640 parts of a sulfonated copolymer of styrene and divinylbenzene having a bulk density of 0.640 kg / 1, is heated to 130 ⁰ C. A mixture which is obtained from 5020 parts of freshly distilled o-toluidine and 1000 parts of 37% aqueous formaldehyde after removal of the water introduced and formed by distillation flows in continuously at the upper end of the tube in proportion to the drain. At the lower end, a constant flow of 90 parts per hour is set. The storage vessel for the mixture to be dispensed, the tube filled with the catalyst and the collecting vessel are kept under a nitrogen atmosphere. The reaction mixture contains 45.5 parts of unreacted o-toluidine and 37 parts of 4,4'-diamino-3,3'-dimethyldiphenylmethane, which are separated by fractional distillation. The yield is 85% of theory, based on converted o-toluidine.

The catalyst has a shelf life and duration of action of over 4000 hours. When working in the presence of oxygen, the service life is of the catalyst with the same yield only 2500 hours.

Claims (1)

Claim: Modification of the process for the preparation of 4,4'-diaminodiphenylmethanes of the general formula wherein Ri, R2 and R3 are hydrogen atoms or identical or different alkyl, aryl or cycloalkyl radicals, which have further substituents can carry, R2 and R3 also mean alkoxy groups or halogen atoms, through Implementation of aromatic amines of the general formula which are unsubstituted in the p-position wherein Ri, R2 and R3 have the aforementioned meaning reacting with formaldehyde or under the reaction conditions such as formaldehyde Substances in the presence of acids at temperatures between 70 and 150 ° C, in the presence of catalytic amounts of acids which are present in heterogeneous phase during the reaction, according to patent application B 69931 IVb / 12q, d a characterized in that the Implementation with the exclusion of oxygen or oxygen-containing gases. € 09 508/235 2.66 © Bundesdmckerei Berlin