DE2118490A1 - Process for the production of diamino-diarylmethanes and polyaminopolyarylmethanes - Google Patents

Description

FARBENFABRIKEN BAYER AG LEVERKUSEN- Bayerwerk L / PS / GW. ZentrtlbeieiA J 5, ΑρΓίΙ 197t Patents, trademarks and licenses

Process for the preparation of diamino-diarylmethanes and polyaminopolyarylmethanes

The present invention relates to a method of manufacture of aromatic Dl- and polyamines by reacting aromatic amines with at least one free o- or ρε division with formaldehyde. Process products of this type are particularly suitable for the production of polyamides, Polyurethanes and epoxy resins.

It is well known that the condensation of metals with formaldehyde to give diamino-diaryl methanes and polyamino-polyaryl methanes in the presence of acids, especially hydrochloric acid. This has a very corrosive and musty effect In addition, they are washed out and neutralized in additional work-up steps, so this goes for the process lost and ultimately leads to wastewater contamination

Attempts have therefore been made to carry out the reaction with solid acids, such as acid-activated clays and ion exchangers. However, other difficulties arise: Work should be carried out as free of water as possible so that the Reaction can be brought to an end in economically short times. Still, reaction tents are up to 10 hours required and the catalysts must be carefully separated and replaced after a certain period of time or regenerated (cf. DAS 1 179 945 and DOS 1 493 431) or similar

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It has also been suggested that the condensation of anilines and formaldehyde with salts such as NaCl and NH.C1 to catalyze. These salts also cause corrosion. You either wash them off or, as this is an additional one Means effort, they are often left in the reaction product, where they are either on in further work-up steps Vessel material, or on plastics into which the reaction product is normally processed, there is considerable corrosion cause.

In the known processes, predominantly p-substituted aromatic amines are obtained, which easily crystallize. Pure however, processing products which are liquid at room temperature are very desirable for further processing.

It has now been found that the aforesaid difficulties and drawbacks can be overcome if one carried out the reaction of anilines with formaldehyde without any catalyst at temperatures above 200 ⁰ O. In extremely short reaction times of a few minutes, non-corrosive reaction mixtures which are free of foreign substances and which can be distilled immediately, and water can also be separated off at the same time. The diamine mixtures formed have such a favorable composition that they practically do not crystallize even at room temperature. The yields of diamine-polyane ring mixtures are good to very good.

The invention thus provides a process for the preparation of diamino-diarylmethanes .and polyamino polyarylmethanes by condensation of formaldehyde with aromatic amines, which is characterized by bringing the pure AusgaugsproduJrte to temperatures above 200 ⁰ O. Purely for the purposes of the invention are starting products that do not contain any acids or salts.

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It is very astonishing that the reaction can even be carried out with the pure substances. This contradicts current ideas about the course of the rearrangement of N, N'-methylenebisanilines in particular in core-linked diaminodiarylmethane, which should be acid or salt catalysed. It was still not closed expect that the process according to the invention will produce an isomer distribution which is so favorable for further industrial processing receives.

The reaction is conducted at temperatures between 200 ° -, especially 220 35O ⁰ O - expediently carried out 300 ⁰ C in pressurized containers under the autogenous pressure. Very high-boiling amines can also be used at normal pressure.

The reaction time is not very critical and can vary between a few minutes and several hours. You influenced the ratio of diamines to polyamines and the ratio of diamine isomers to one another only slightly. The amine / formaldehyde reactant molar ratio depends on the desired proportion of diamines or polyamines in the reaction product and ranges roughly between 30: 1 to 1: 1, preferably 20: 1 to 3: 1.

Although the reaction can easily be carried out batchwise, the short reaction time and offers since only liquid products have to be fed in and out, ideal conditions for continuous Way of working. The reaction can take place in a heated pipe coil, and the reaction product directly passed into a distillation column and utilizing the heat supplied to the mixture and the heat of reaction be fractionated.

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The water of reaction or that added with formalin Water can be removed, but it can also be left in the reaction mixture without impairing the reaction rate in contrast to those with solid catalysts working procedures.

Suitable starting materials for the process according to the invention are:

a) aromatic amines with at least one free o- or p-division, which do not have more than one second substituent Order how cyan, nitro, carboxy are supposed to contain. Aniline are particularly suitable, and alkyl anilines are preferred 1-8 carbon atoms in the alkyl radical, the alkyl radicals in the Amino group and / or in the aromatic nucleus as substituents, such as N-methylaniline, N, N-dimethylaniline, o-toluidine, 2,6-dimethylaniline, m-propylaniline, o-butylaniline, haloanilines, preferably chlorine and bromanilines, such as o-chloroaniline, m-bromaniline, phenoxy and alkoxyanilines with preferably 1-4 carbon atoms in the alkoxy group, such as o-methoxy or o-phenoxyaniline, furthermore Anthranilic acid ester, diphenylamine, naphthylamine, o-phenylenediamine

b) Formaldehyde as such, then in the form of polymers Formaldehyde, e.g. paraformaldehyde, in aqueous solution (formalin) and as methyl.

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example 1

1000 g of aniline (freshly distilled) and 30 g of paraformaldehyde are heated to 280 ⁰ O for _{2 h in a clean 2 l steel autoclave with stirring and N 2.} After the water and aniline have been distilled off, 163 g of viscous brown residue remain, which is separated by distillation in a portion (of 139 g) which, according to NMR analysis, is a mixture of isomeric diaminodiphenylmethanes passing over at 187-220 ° / 0.3-0.5 Torr represents and a resinous residue of polyamines (23 g). Yield based on CH ₂ O of diamines is 70 $ of theory; of diamines and polyamines $ 85> d.Th.

Example 2

1000 g of aniline and 86 g of 35% formalin are reacted as in Example 1. After the aniline and water have been distilled off, 168 g of viscous brown, non-crystallizing residue remain which, according to gas chromatographic analysis, consist of 13 > 2.2 ^t -diamino-diphenylmethane 37 # 2,4'- "40 £ 4,4'-" 10 % polyamine

consists. The yields based on CH ₂ O of di- and polyamines is 87 fi of theory.

Example 3

The batch according to Example 1 is held at 25O ⁰ C for 2 h.

This gives 174 g of water and aniline-free product which according uaschromatogramm of 20.8 · _{2,2'-Diamino-diphen>} ylmethane

34.4 * 2.4'- "

34.4 % 4,4'- "

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9.4 $> consists of polyamines and does not crystallize. The amine yield is 91%. Th.

Example 4

The batch according to Example 2 is ^{kept at 280 0} O for 5 h. 163 g of aniline-free and anhydrous residue are obtained, which is separated into 27 g of a resinous residue and 136 g of volatile matter by high vacuum distillation. The distillate contains:

P IO i> 2,2'-Diaminodiphenylmethane 40.5 # 2,4'- "41 * 4,4'-"

8.5 % polyamine

The yield of diamine and polyamine is 86 % of theory.

Example 5

The approach according to Example 1 is repeated. TJm any Acid traces cannot be excluded with absolute certainty very pure paraformaldehyde, freshly distilled and with Caustic soda and distilled water "washed aniline" and one with caustic soda and distilled water carefully cleaned autoclave used.

178 g of aniline and anhydrous amine mixture are obtained, the after gas chromatography

10.7 # 2,2'-Diaminodiphenylmethane 44 3 * 2,4'- " $ 35>4,4'- · 'and 9 i> polyamine

contains.

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Example 6

The batch according to Example 2 is brought to 280 ^° C. and allowed to cool immediately. 185 g of a light brown resin which does not crystallize and has the following composition are obtained

$ 9.6> 2.2 ^l -Diamino-diphenylmethane 36 io 2,4'- "
46 £ 4,4'- "

8 # polyamine

The yield is $ 96> d.Th.

The diamine mixture obtained by distillation was also still amorphous after 2 weeks at room temperature.

Example 7

500 g aniline (freshly distilled) and 86 g 35% Formalin are implemented as in Example 2. 163 g of a product are obtained which, after distillation, consists of 70% diamine and 30% polyamine ".
Yield: 90 # of theory

Example 8

1000 g N-methylaniline (freshly distilled) and 86 g 35% Formalin are implemented as in Example 2. 215 g of a light brown, non-crystallizing viscous material are obtained Oil, which after distillation from 191 g of bis-N-methyland.nodiphenylmethanen (not crystallizing) and 24 g of polyamine. Yield: 97 # of theory

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Example 9

450 g o-toluidine (freshly distilled) and 40 g 35% Formalin are implemented as in Example 2. 91 g of product are obtained, which consists of 80 g of bis-2-methylamino-dlphenylmethanes and 11 g of polyamine.
Yield: 90 i "theory

Example 10

650 g N, N-dimethylaniline (freshly distilled) and 56 g 35% Formalin are implemented as in Example 2. 73 g of brown resin are obtained, which consists of 69 g of bis-NjN-dimethylaminodiphenylmethane and 4 g of polyamine. Yield: 46 % of theory Th.

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Claims (1)

Claim: A process for preparing diamino-diarylmethanes and Polyaminopolyarylmethanen by reacting aromatic amino compounds with formaldehyde and / or Pormaldehydspendern, characterized in that heating the mixed reactants in the absence of catalysts at temperatures above 200 ^0C. le A 13 670 - 9 - 209844/1137