DE1056619B - Process for the preparation of 4-nitro-diarylamines - Google Patents

Description

GERMAN

It is known that p-chloro-nitrobenzene with Can convert ammonia or aliphatic amines to p-nitroaniline or N-substituted p-nitroanilines (see German patent specification 148 749). When using aromatic amines, however, technical unsatisfactory yields achieved. Also in the case of the one described in German patent specification 185 663 Procedure in which in the presence of copper iodine or mixtures of copper powder and "iodine is worked, satisfactory yields are not obtained.

It has now been found that 4-nitro-diarylamines obtained in good yield if optionally substituted p-halonitrobenzenes with optionally substituted arylamines acylated on nitrogen.

For the process according to the invention suitable p-Halogermitrobenzenes are, for. B. p-chloro-nitrobenzene, p-bromonitrobenzene or 1,2-dichloro-4-nitrobenzene. Suitable acylarylamines are, for. B. formanilide, acetanilide, Formyl-a-naphthalide and formyl-p-toluidide.

The process according to the invention is expediently carried out at an elevated temperature, e.g. B. at 150 to 250 ° C, preferably 180 to 220 ⁰ C; however, higher or lower temperatures can also be used. In general, it is advantageous to work in the presence of copper powder or a copper compound. In order to bind the hydrogen halides formed in the reaction, it is expedient to use acid-binding compounds, e.g. B. alkali carbonates, alkali acetates or magnesium oxide ". In general, it is not necessary to use a solvent, but it is also possible, if desired, to work in the presence of inert solvents.

It is also not necessary to use the acyl derivatives of the arylamines directly, but rather one can also produce these compounds only in the reaction mixture from the starting components.

A particular advantage of the process according to the invention is that the 4-nitro-diarylamines in very in pure form, so that they can be processed further in many cases without prior isolation. So the 4-nitro-diphenylamine z. B. without prior Isolation by catalytic hydrogenation in 4-amino-diphenylamine can be performed.

example 1

A mixture of 78 parts of p-chloro-nitrobenzene, 95 parts of formanilide, 40 parts of potassium carbonate and

1 part of copper oxide is poured into a stirred flask

2 hours at 180 ° C, then 1 hour at 190 ° C and Heated to 200 ° C. for 2 hours, then cooled to 80 ° C., diluted with 150 parts of benzene and while still hot Process for the preparation of 4-nitro-diarylamines

Applicant:

Paint factories Bayer Aktiengesellschaft, Leverkusen-Bayerwerk

Dr. Klaus Schwarzer, Koln-Flittard, and Dr. Rudolf Stroh, Leverkusen, have been named as inventors

filtered off from the inorganic salts. When the solution cools, 53 parts of 4-nitrodiphenylamine crystallize, Melting point of the crude product 127 to 130 ° C. By concentrating the mother liquor can the yield can still be increased.

Example 2

A mixture of 78 parts of p-chloro-nitrobenzene, 95 parts of formanilide and 40 parts of potassium carbonate is heated to 200 ° C for 5 hours. Then unreacted p-chloro-nitrobenzene and Formanilide stripped off with steam. 85 parts of 4-nitro-diphenylamine remain as residue. Melting point of the crude product: 125 to 126 ° C.

B e i s ρ i e 1 3 35

A mixture of 78 parts of p-chloro-nitrobenzene, 70 parts of aniline and 35 parts of formic acid (D = 1.22) is heated in a stirred flask equipped with a descending condenser. After most of the water of reaction has distilled off, 60 parts of potassium carbonate and 1 part of copper oxide are added and the mixture is then heated to 200 ° C. for 5 hours. Unreacted p-chloro-nitrobenzene and aniline or formanilide are then driven off with steam. 91 parts of 4-nitro-diphenylamine remain as residue.

Example 4

A mixture of 78 parts of p-chloro-nitrobenzene, 67.5 parts of acetanilide, 50 parts of potassium acetate and 5 parts of copper oxide are heated to 200 ° C for 5 hours, then diluted with benzene and still hot from the inorganic salts filtered off. On cooling, 4-nitro-diphenylamine crystallizes from the solution.

909 509/436

Heated to 200 ° C and the solution filtered while still hot. Crystallize from the filtrate on cooling 62 parts of 2-chloro-4-nitro-diphenylamine from. Melting point of the crude product 107 to 108 ° C (according to the Recrystallize from alcohol. M.p. 113 ° C .;

Example 9

A mixture of 78 parts of p-chloro-nitrobenzene, 95 parts of formanilide, 50 parts of potassium carbonate and

ίο \ part of copper oxide is heated to 180 ° C for 8 hours together with 80 parts of xylene. The water formed during the reaction is continuously removed from the reaction mixture by azeotropic distillation. After the reaction has ended, the solvent and unreacted starting materials are driven off with steam. 107 parts of 4-nitro-diphenylamine remain.

Claims (3)

Claims. ao 1. Process for the preparation of 4-nitrodiarylamines, characterized in that one optionally substituted p-halonitrobenzenes with optionally substituted arylamines acylated on nitrogen. 2. The method according to claim 1, characterized in that one is in the presence of acid-binding Means works. 3. embodiment of the method according to claim 1 and 2, characterized in that one the arylamines acylated on nitrogen are only generated in the reaction mixture. The determination of the inorganically bound chlorine showed a conversion of 55% of theory. Example 5 A mixture of 78 parts of p-chloro-nitrobenzene, 105 parts of form-p-toluidide, 40 parts of potassium carbonate and 1 part of copper oxide is heated to 200 ° C for 5 hours, after cooling to 80 ° C with 150 parts Diluted benzene and filtered while hot. On cooling, 55 parts of 4-nitro-4'-methyl-diphenylamine separate from the solution away. Similar results are obtained using form-o-toluidide. Example 6 A mixture of 78 parts of p-chloro-nitrobenzene, 128 parts of the form-crnaphthalid, 40 parts of potassium carbonate and 1 part of cupric oxide is heated for 5 hours at 200 ⁰ C, after cooling to 8O ⁰ C diluted with 150 parts of benzene and filtered hot. 85 parts of N- (4-nitrophenyl) -a-naphthylamine crystallize out from the filtrate. Mp 164 to 167 ° C (after recrystallization from xylene mp 173 to 174 ° C). Example 7 A mixture of 78 parts of p-chloro-nitrobenzene, 63 parts of p-nitroformanilide, 40 parts of potassium carbonate and 1 part of copper oxide is heated in 250 parts of nitrobenzene at 200 ° C for 5 hours and the The solution is then nitrated from the inorganic salts while it is still hot. Crystallize from the filtrate on cooling 17 parts of 4,4'-dinitro-diphenylamine. Example 8 A mixture of 95 parts of 1,2-dichloro-4-nitro- Publications considered: Benzene, 95 parts of formanilide, 40 parts of potassium carbonate 35 Beilstein, Handbuch der Organic Chemie, bonate and 1 part of copper oxide is 5 hours on 4th edition, Hptw. Vol. 12, p. 240. ® 909 509/436 4. 59