SU1049481A1 - Process for preparing bis(4-aminophenyl)disulfides - Google Patents

Abstract

METHOD OF OBTAINING BIS

Description

1: about 1 x of the Invention. It relates to a method for producing bis (4 amino-enyl) disulfides, which are widely used in the preparation of fungicides, photosensitive compositions, rubber, polyurethane, as well as improve the adhesion of polymers and improve the properties of aviation gasoline. A known method of producing bis (4-aminophenyl) disulfides involves boiling the ring-substituted PG-chloronitrobenzenes with an aqueous solution of hydrosulfide or sodium sulfide ij. However, this method can be used to obtain only bis (4 aminophenyl) disulfides with a primary amino group. A method for producing bis (4-aminophenyl) disulfides is also known by reducing the charging medium of the corresponding sulfonic chlorides 2j. The disadvantages of this method are the use of inaccessible 4-aminophenylsulfonyl chloride, the multistage method and the high corrosiveness of the reaction medium. The closest to the invention is a method for producing bis (4-aminophenyl) disules |) idov5 consisting in that the mixture of the corresponding 4-rhodananiline and sodium sulfide nonahydrate is boiled in water until complete dissolution (-3 h), filtered, acidified with acetic acid, a solution of aqueous ZOH-nddo caustic soda is added, and then 30% -HVK hydrogen peroxide is added dropwise at C, filtered after 1 h, the precipitate is crystallized from aqueous alcohol. Code of Target Product 80% 3j. The disadvantages of this method are not sufficiently high yield of the target product, the two-stage processes by its large continuation Synthesis conditions

The yield is 2–8 hours (2–4 h), the use of a concentrated solution of hydrogen peroxide and the release of toxic hydrogen sulfide. The purpose of the invention is to increase the yield of the target product and simplify. process. The goal is achieved according to the method for producing bis (4-aminophenyl) disulfides, which means that the corresponding 4-rhodananiline in dioxane at 50120 ° C is reacted with an aqueous solution of ammonia, taken in quantity. 3-10 moles per 1., mol 4-ro-I dananiline, followed by precipitation of the target product from the reaction mixture with water. An aqueous ammonia solution is used as a base, taken in an amount of 3-10 moles per 1 mole of 4-rhodanese anestine, dioxane is used as a solvent, and the process is carried out: at 50-120 ° C, followed by precipitation of the desired product with water. A 5-7 fold amount of water is used. The precipitated disulfide crystallization of water d1-goxane. During heating, the reaction mixture turns black, which is caused by the formation of colored polymers of hydrogen hysteresis. Free cyanide, hydrogen under synthesis conditions is not released. The insoluble portion, the polymer is 6-8% by weight of the starting 4-rhodananiline, and is easily removed during crystallization. The effect of synthesis conditions on the formation of bis (4-aminophenyl) disulfide in the reaction of 4-rhodananiline (4-PA) with an aqueous solution of ammonia (23%) in the presence of dioxa and Tl ml per 1 ml of aqueous solution of ammonia is given in table). T a b l and c a. one

10 10 30

120 110 100

85.3

3 3 7 95.1 87.3

The lower limit of the indicated tester interval () is due to a significant increase in the duration of the reaction at lower 35 temperatures, the upper one.140 ° C - a decrease in product yield at higher temperatures due to the occurrence of side reactions. Increasing the excess of ammonia above these limits is impractical because it does not increase the yield of the product. The decrease in the amount of ammonia, below 3 mol per 1 mol 4-rodanash “Shna leads to the transformation of the last 5 in the polymer. Reducing the ammonia concentration to a noticeable degree lengthens the synthesis time by diluting the reaction mixture.

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The effect of the concentration of aqueous ammonia on the formation of bis (4-aminophenyl) disulfide a in 4-rhodananiline in the presence of dioxane (mp per 1 MP of an aqueous solution of ammonia) SS at a molar ratio of NH tj-PA equal to 5, and a temperature of 100 C is given in Table . 2.,

Continuation of table 1

Table 2

Heating is carried out until the reaction mixture turns black.

P f and me er 1. Bis (4-aminophenyl) disulfide.

A mixture of 0.3 g (2 mmol) of 4-aminophenyl thiocyanate, I 26 mp (14 mmol) of aqueous ammonia and 1.26 ml of dioxane is heated in a sealed ampoule at 100 ° C for 30 minutes. Then the ampoule is cooled, opened, and the contents are treated with water. The product, B1 | 1, is precipitated, crystallized from water dioxane. Obtain 0.22 g of substance (87.3%), tg. 75-7bOs

PRI mme li 2, Bis (4-amino-3-methylphenyl) disulfide.

A mixture of 0.33 g (2 mmol) of 4-amino-3-methylphenyl thiocyanate, 0.54 ml (b mmol) of aqueous ammonia and 0.54 ml of dioxane is heated in a sealed vial for 30 minutes. Then the vial is opened, and the contents are treated analogously to the example. Obtain 0.27 g of yyotvstva (98.7%), so pl. SCHOS.

Example 3. Bis (4-dimethylaminophenyl) disulfide.

A mixture of 0.35 g (2 mmol) of 4-dimethylaminophenylthiocyanate, 0.9 ml

(10 mmol) of aqueous ammonia and 0.9 ml of dioxane are heated in a sealed ampoule for 30 minutes. Then the ampoule is cooled, opened, and the contents are treated in the same way as in Example 1, 0.9 g of the substance is obtained (96.8%), ie 117-P8c.

The invention allows to duplicate the yield of the target product to (80% yield by a known method). The process is simplified by conducting it in one stage and shortening the duration to 0-HZO (instead of 2-4 hours as known) improves working conditions by eliminating the release of harmful gaseous substances in the process, and also reduces the need for using hydrogen peroxide.

Claims (1)

METHOD FOR PRODUCING BIS (4-AMINOPHENYL) DISULFIDES by reacting the corresponding 4-rhodananiline with a base in a solvent by heating and isolating the target product, so that in order to increase the yield of the target product and simplify of the process, an aqueous solution of ammonia taken in an amount of 3-10 moles per 1 mol of 4-rhodananiline is used as a base, and dio- as a solvent. dignity, the process is carried out at 50-120 ° C, and the allocation is by precipitation with water. ·