DE420754C - Process for the preparation of chlorine-substituted aromatic amines - Google Patents

Description

Process for the preparation of chlorine-substituted aromatic amines. It has been found that the highly chlorinated, nitrogen-containing, hydroaromatic products obtainable by the processes of patent 400254 and additional patent 419814 can be reduced. The surprising observation was made that it is easy to conduct the reaction in such a way that all of the nitrogen is retained in the molecule and thus chlorine-substituted aromatic amines are obtained. It is essential that hydrolysis is avoided as far as possible. However, since the chloroketimides obtainable by the process of patent 400254 represent relatively stable bodies, which only occur when standing with mineral acids or when boiling. convert with these into the corresponding ketones, so even when working with acids, provided that one reduces rapidly, the amine is obtained in good yields. It was also found that the end product of the reduction depends on the reducing agent used. Strong reducing agents, such as zinc and hydrochloric acid, tend to split off more chlorinators than weak ones. Among the latter, an ethyl or methyl alcoholic solution of anhydrous sodium sulphide or, in cases in which this is still too strong, alcohol alone has proven to be particularly favorable. Some of the nuclear chlorinated amines obtained in good yields are still unknown bodies, such as 2, 3, 4-trichloro-i-aminonaphthalene melting point 162 °; Analysis: calc. 43.18, found 4302 percent chlorine, the 1,3-dichloro-2-aminonaph t'halin mp 93.5 °; Analysis: found 33.43, calculated 3344 percent chlorine (perhaps the 3,4-dichloro-2-aminonaphthalene is also present here), the 2,3,4-trichloro-i-aminoanthraquinone mp 20 °; Analysis: found 30.9 percent, calc. 32.1 percent chlorine and a dichloro-i-aminoanthraquinone mp 204 °; Analysis: found 24.8 percent, calculated 24.29 percent chlorine.

In part, the specified procedure is a simpler representation known body.

The pentachloroaniline has only been very cumbersome to this day accessible (see reports of the German chemical society, vol. 43 [1910], p.2753), while after the procedure specified here in a short time and with cheap starting materials large quantities of this product can be produced in pure form; the same also applies to 2, 3, 4, 6-tetrachior-i-aminoibenzene. Also that of C 1 a u s (Journal for practical chemistry, N.F. Vol. 57, p. i) described 1, 3, 4-trichloro-2-aninonaphthalene is advantageously represented by the present process. Examples. i. Hexachlorochloroketiminotetrahydrobenzene is dissolved in methyl alcohol and in a saturated methyl alcoholic solution of Sodium sulfur poured in. After the reaction has ended, it is diluted with water, whereby the 2, 3, 4, 6-tetrachloro-i-aminobenzene precipitates. It leaves recrystallize from petroleum ether.

2. Octochlorochloroketiminohexahydrobenzene is reduced as in Example i. The pentachloroaniline is obtained in a yield of approximately go percent.

3. Dissolve 2509 anhydrous sodium sulfide in hot alcohol, then filter the solution and cool. A quantity of sodium sulphide crystallizes out and is left in the solution. Now, by keeping the temperature continuously at 30 °, zoo g of pentachloro-13-chloroketiminotetrahydronaphthalene are added in small amounts. After the reaction has ended, the mixture is warmed up a little on the water bath. The solution is then mixed with water, the amine precipitating and any chlorine-substituted naphthol formed remaining in solution. The precipitate is dried and recrystallized from gasoline. Yield: about go percent of pure 1,3,4-trichloro-2-aminonaphthalene.

4. As in Example 3, except that the α-chloroketimine derivative is used instead of the ß-chloroketimine derivative. The 2,3,4-TriOhlor-i-aminonaphthalin is obtained in good yields. . -5. Pentachloro-ß-chloroketiminotetrahydronaphthalene is dissolved in methyl alcohol and small amounts of hydrochloric acid and zinc dust are added to the solution. After the reaction has ended, it is filtered and the filtrate is mixed with water, the amine precipitating contaminated with a little naphthol. The latter is removed by exhaustion with sodium carbonate. The dried amine is recrystallized from methyl alcohol. The dichloro-2-aminonaphthalene yield is approximately 78 percent of theory.

6. Pentachloro-a-chloroketiminotetrahydroanthraquinone is in alcohol boiled for several hours on the reflux condenser. The 2,3,4-trichloro-i-aminoanthraquinone sic12 separates out and is obtained in pure form and in good yield.

7. Pentachlor-c @ -chlork etiminotetrahydroanthrac'hinon is in small Auteilen entered into a solution of tin chloride in methyl alcoholic hydrochloric acid. When the reaction has ended, the mixture is heated to boiling, the amine is precipitated with water and separated from the hydroxyl derivative by treatment with sodium carbonate solution. One crystallizes the dichloro-iamino-anthraquinone, from benzene.

Claims (1)

PATr, NT-ANSPRUCFI: Process for the preparation of chlorine-substituted aromatic amines, characterized in that the mau by the method of Patent 400254 and the additional patent 419814 available highly chlorinated, nitrogen-containing., hydroaromatic products while avoiding hydrolysis with suitable reducing agents treated.