DE1179945B - Process for the preparation of 4,4'-diaminodiphenylmethanes - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: C 07 c

German class: 12 q- 1/02

Number: 1179 945

File number: B 69931IV b / 12 q

Filing date: December 11, 1962

Opening day: October 22, 1964

Bases of the diphenylmethane series can be obtained by condensation of aromatic amines with formaldehyde Produce in acidic, especially hydrochloric acidic medium. One can also use aromatic amines and Formaldehyde in neutral, aqueous or alkaline alcoholic solution to methylenediamines, polymers React methylenamines or to the cyclic, so-called anhydroformaldehyde bases, which then with excess aromatic amine and excess hydrochloric acid or with aromatic Amine and its hydrochloric acid salt at elevated temperature, the hydrochloric acid salts of the diphenylmethane bases result. These are then converted into the appropriate bases with soda or caustic soda Converted diphenylmethane series. So you need the acid and the base in this process stoichiometric amounts, based on the bases.

It has been found that 4,4'-diaminodiphenylmethanes of the general formula

CH ₂

wherein Ri, R.2 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

where Ri, R2 and R3 have the aforementioned meaning, with formaldehyde or substances reacting under the reaction conditions such as formaldehyde in the presence of acid at temperatures between 70 and 150 ^° C. in a simpler manner if the reaction is carried out in the presence of catalytic amounts of acids , which are present in a heterogeneous phase during the implementation.

The fact that the acids used do not during the reaction is of particular advantage can be changed and can be used for further approaches without regeneration.

Method of manufacture

of 4,4'-diaminodiphenylmethanes

Applicant:

Aniline & Soda Factory in Baden

Aktiengesellschaft, Ludwigshafen / Rhein

Named as inventor:

Dr. Hugo Kröper, Heidelberg,

Dr. Rolf Platz, Mannheim,

Dr. Helmut Schmidt, Ludwigshafen / Rhine

It is another major advantage of this invention that the acids can be converted into catalytic Can use quantities and no unwanted salts, which in the previously required release the bases formed from their salts, receives.

It is surprising that the preparation of bases of the diphenylmethane series in the presence of catalytic amounts of acids which are present in the heterogeneous phase during the reaction with can carry out such good yields, since it is known from US Pat. No. 2,818,433 that the yield is reduced if more or less than the equivalent amount of acid is used.

The aromatic amines which are unsubstituted in the p-position and used as starting materials correspond the general formula

Such compounds can e.g. B. be: aniline, N-methylaniline, N-ethylaniline, o-toluidine, N-ethylm-toluidine, N-isobutylanisidine, m-chloroaniline. Next to Formaldehyde can also be used with substances that release formaldehyde under the reaction conditions. Such substances are z. B. paraformaldehyde, polyoxymethylene or methylal.

Acids which are present in the heterogeneous phase during the reaction are in the sense of this Invention to understand acidic ion exchangers. It

409 708/410

are either acidic inorganic Al-Si-containing ion exchangers, such as natural or artificial molecular sieves of the zeolite type, such as mordenite, or polymerization or condensation products that have an aromatic hydrocarbon skeleton that contains mineral acid groups, e.g. B. sulfonic acid residues, of sufficiently high molecular weight and which are sufficiently branched or crosslinked, so that insolubility in the aromatic amine solutions and stability up to temperatures around 150 ⁰ C is given. The polymers or condensates can be prepared from a wide variety of monomers and in various ways. You can in the monomers, for. B. styrene or phenol, introduce mineral acid groups by conventional methods and then polymerize or condense with formaldehyde. But you can also z. B. carry out a sulfonation on the finished polymer or condensate in the usual way.

Catalysts made from 92 to 99 percent by weight styrene and 1 to 8 percent by weight are very effective Divinylbenzene, especially when these copolymers have at least 0.5 sulfonic acid group each aromatic ring included.

Instead of styrene and divinylbenzene, copolymers of other monovinyl-aromatic compounds, z. B. methylstyrene, p-ethylstyrene, dimethylstyrene, p-chlorostyrene, dichlorostyrene, vinyl naphthalene and other polyvinyl aromatic compounds, e.g. B. divinyltoluene, divinylchlorobenzene, be used. To display the condensates, for. B. monohydric and polyhydric phenols or Cresols can be used.

Particularly good catalysts for the preparation of the diphenylmethane bases are made by sulfonation obtained from styrene-divinylbenzene copolymers. They show the best catalytic effectiveness when that Copolymers made from 96 to 98 weight percent styrene and 2 to 4 weight percent divinylbenzene is and by sulfonation at least one, preferably several sulfonic acid groups per aromatic ring contains.

The grain size of the catalyst can be kept within wide limits, e.g. B. 10 to 0.01 mm. Particularly good results are achieved when the catalyst has a grain size between 0.3 and 0.04 mm having.

The catalyst is used in amounts of 50 to 25 percent by weight, that is 0.3 to 0.1 acid equivalents, based on the aromatic to be converted Amine, added, with one sulfo group per aromatic ring in the polymer.

2 moles of aromatic amine can be reacted with 1 mole of formaldehyde. It is advantageous to turn but the aromatic amine in excess, e.g. B. about 2.2- to 10-fold molar excess.

In the discontinuous process, the starting materials can be heated together with the catalyst to temperatures between about 80 and 130 ^° C., advantageously about 100 to 110 ^° C., with stirring. The reaction time depends on the selected temperature. If reaction ^{temperatures below 100 °} C. are chosen, it is expedient to keep the reaction mixture at this temperature for 20 to 30 hours. When working at temperatures between 100 and 13O ⁰ C, so usually suffice reaction times between 6 and 8 hours. The water that forms and the water of a z. B. aqueous formaldehyde solution can be distilled off continuously. After the reaction, the catalyst, e.g. B. separated by filtering off the reaction mixture. It can be fed back into a new batch without intermediate treatment. The filtrate can be in a known manner, for. B. work up by fractional distillation in vacuo. The diaminodiphenylmethane bases produced in this way are valuable intermediate products for the production of dye and lacquer raw materials. They can also be used directly without prior cleaning.

'It is also possible to use the diaminodiphenylmethane bases to be obtained in a continuous process. For this purpose, a column heated to the required reaction temperature is charged with the acid and the starting mixture is either added to the top of the column or through from the bottom pressed the catalytic converter. The processes of the column then contain the end products that z. B. by subsequent Pure distillation can be obtained.

The parts mentioned in the examples are parts by weight.

example 1

700 parts of aniline, 100 parts of a polymerization product, which was obtained by polymerization and subsequent sulfonation of styrene and divinylbenzene, and sulfuric acid, and 164 parts of 37% formaldehyde solution are mixed in a stirred apparatus with an attached distillation bridge, heated to 110 ⁰ C and the water present is distilled off . After stirring for 20 hours at 110 ⁰ C is centrifuged off from the catalyst and distilled the clear, light brown colored solution. 289 parts of 4,4'-diaminodiphenylmethane distill over at 210 to 215 ° C. at 4 torr. The yield is 84% of theory, based on converted aniline.

Example 2

450 parts of o-toluidine, 50 parts of a polymerization product obtained by polymerization of styrene and divinylbenzene and subsequent sulfonation with chlorosulfonic acid, and 82 parts of 37% formaldehyde solution are reacted ^{at 130 ° C. for 8 hours.} The catalyst is then filtered off. Distillation of the filtrate gives 181 parts of 4,4'-diamino-3,3'-dimethyldiphenylmethane with a boiling point of 230 to 235 ^° C. below 4 torr. The yield is 85% of theory, based on converted o-toluidine.

Example 3

450 parts of methyl aniline, 50 parts of the catalyst described in Example 1 and 82 parts of 37% strength formaldehyde solution are reacted at 110 ^° C. for 15 hours in the same apparatus. After working up, 145 parts of 4,4'-dimethylamino-diphenylmethane with a boiling point of 250 to 260 ^° C. at 4 torr are obtained. The yield is 72% of theory, based on converted methylaniline.

Example 4

A vertical steel pipe (4.5 x 120 cm), which is surrounded by a heating jacket, is with

640 parts of a polymerization product obtained from styrene and divinylbenzene followed by sulfonation and a bulk density of 0.64 kg / 1 has filled and heated to 130 ⁰ C. A mixture obtained from 5020 parts of o-toluidine and 1000 parts of 37% strength aqueous formaldehyde solution and the water introduced in the formaldehyde and formed during the reaction was removed in vacuo, is continuously added to the upper end of the tube in proportion to the runoff. A constant rate of 90 parts per hour is set at the lower end of the tube. The reaction mixture contains 46.1 parts of unreacted o-toluidine and 36.6 parts of 4,4'-diamino-3,3'-dimethyldiphenylmethane, which are separated by fractional distillation. The yield of 4,4'-diamino-3,3'-dimethyldiphenylmethane is 84% of theory, based on converted o-toluidine. The recovered toluidine can be used to prepare a new starting mixture. The catalyst was used without regeneration and the yield remained the same for 2500 hours.

Example 5

250 parts of o-toluidine, 50 parts of a synthetic acidic mordenite and 41 parts of 37% formaldehyde solution are reacted ^{at 130 ° C. for 8 hours.} The catalyst is then filtered off. 90 parts of 4,4'-diamino-3,3'-dimethyldiphenylmethane are obtained by distillation. The yield is 82% of theory, based on converted o-toluidine.

25th

Claims (1)

Claim: Process for the preparation of 4,4'-diaminodiphenylmethanes of the general formula Ri R ₂ R ₂ Ri wherein Ri, R ₂ and R3 are hydrogen atoms or identical or different alkyl, aryl or cycloalkyl radicals which can also carry further substituents, R ₂ and R ₃ also mean alkoxy groups or halogen atoms, by reaction of aromatic amines unsubstituted in the p-position in general formula R ₂ Ri ΛΤΛ R ₃ wherein Ri, R ₂ and R _{3 have} the meaning given above, substances which react with formaldehyde or under the reaction conditions such as formaldehyde in the presence of acids at temperatures between 70 and 150 ⁰ C, characterized in that the reaction is carried out in the presence of catalytic amounts of Acids that are present in the heterogeneous phase during the reaction. 409 708/410 10.64 0 Bundesdruckerei Berlin