CS207105B1 - Method of making the 2,2-dibenzoyldiaminodiphenyldisulfide - Google Patents

Description

DESCRIPTION OF THE INVENTION

ON THE CERTIFICATE OF CERTIFICATE CZECHOSLOVAK SOCIALISTREPUBLIC (19) 207 105 (11) (Bl)

(61) (23) Show Priority (22) Enrolled 1θ 79 (2!) PV 6578-79 (51) Int.Cl? OJ C 07 c 149/42

OFFICE OFFICE

AND DISCOVERIES (40) Published 15 09 80 (45) Published 01 11 83

Author of the invention MORAVEC PETER ing., KAČÁNI STANISLAV ing. CSc., ŘEŽÁBEK ANTONÍN KNDr., BRATISLAVA (54)

A method for producing 2,2'-dibenzoyldiaminodiphenyl disulfide 1

BACKGROUND OF THE INVENTION The present invention relates to the production of 2,2'-dibenzoyldiaminodiphenyl disulfide by alkali hydrolysis of a benzothiazole, by oxidation of 2-aminothiophenol sodium salt with hydrogen peroxide and benzoylation of 2,2'-diaminodiphenyl disulfide with benzoyl chloride.

The method of the invention is within the scope of the possible uses of benzothiazole, which is the product of the high-pressure synthesis of 2-mercaptobenzothiazole by reaction of aniline carbon and sulfur. By the thermodegradation of 2-mercaptobenzothiazole at temperatures above 250 ° C, an average of 6 weight percent benzothiazole per embedded aniline is formed in the feed or continuous tubular reactors. One possible way of using it is to recycle it to the reactor, the next is to produce dibenzothiazole, but the most effective way to process it is to purify the crude benzothiazole-containing fraction by rectification under reduced pressure, followed by hydrolysis of the pure component in an alkaline medium. Sodium salt of 2-aminothiophenol. Several methods of alkaline hydrolysis of benzothiazole, its 2-chloro, optionally 2-phenyl derivatives followed by oxidation of 2-aminothiophenol salt solutions to 2,2'-diaminodiphenyl disulfide with optional benzoylation, are known from the literature review.

For example, Hoffman / Ber. 13,8 (1980) prepared 2,2'-diaminodiphenyl disulfide by melting these benzothiazole derivatives with sodium hydroxide or potassium hydroxide and oxidizing 2-aminothio-207 105 207 103 103 phenolate with air or potassium dichromate. In the past, it was golden that relative milder conditions would be sufficient to open the benzothiazole ring, for example, by hydrolysis with excess concentrated sodium hydroxide over 3 hours / Brit. U.S. Patent 558,887]. According to the process of this patent, sanitized benzthiazole distills with water vapor. Authors document! the rate of hydrolysis to the concentration of alkali hydroxide used and the temperature. Acidification of the aqueous sodium salt with hydrochloric acid or acetic acid (USP 2 791 612) is described to isolate the free 2-aminothiophenol.

Boggust and Cocker / J. Chem. Soc. 355, 1949, disclose the possibility of opening the thiazole ring by hydrazine hydrate in an alcohol medium to form 2-aminothiophenol and by-product (nitrogen, formaldehyde).

Treatment of 2-aminothiophenol, or its sodium salt to 2,2'-diaminodiphenyldi-sulfide by oxidation is not difficult. Usually peroxide is used as an oxidizing agent, but a number of procedures using both dichromate and air alone are known.

Acylation of 2,2'-diaminodiphenyl disulfide with benzoyl chloride is also an older drug. Such as Mohlau and Beyschlag / Ber. 45, 131, 1912] describe the benzoylation of disulfide in ethyl acetate, where 2,2'-dibenzoyldiaminodiphenyl disulfide 8 is obtained by a melting point of 141 ° C. Bogart and Snell / J. Am. Chem. Soc. 46, 1308 (1924) carried out condensation of the solvent at 100 ° C for 1 hour. After crystallization from ethanol, the color needles of the product had a melting point of 142.6 ° C. Clark, J. Chem. Soc. 1928.2313 / worked in a water-alkaline medium and Schotten-Baumann obtained the product with a melting point of 143-144 ° C. From the more recent methods, it is known to prepare N and S substituted 2-aminothiophenol derivatives or disulfide thereof according to the teachings of U.S. Pat. No. 108,079. Bomches et al. they originate directly from the so-called "liquid degassing" arising in the process of industrial production of 2-mercaptobenzothiazole in the reactor. They are subjected to alkaline sodium hydroxide concentration at 80 ° C, optionally at the boiling point of the mixture in a non-pressurized manner or under elevated pressure. Benzothiazole from "liquid degassing" is hydrolyzed to 2-aminothiophenolate and other ingredients such as aniline, thiocarbanilide and anilidobenzothiazoles after separation of the aqueous thiolate solution can return to the reactor to produce 2-mercap tobenzothiazole. The procedure of the second example of the description for MS. No. 108,079 discloses a distillation step prior to alkaline hydrolysis. According to this example, a "liquid off-gas" filler column separates the aniline front fraction and the thiocarbanilide, 2-anilido and 2-mercaptobenzothiazole-containing distillation residues is fused to the reactor as a recycle when combined with the aniline fraction. This process of capturing the pure benzothiazole fraction is more advantageous than the direct hydrolysis of the entire liquid volume.

degassing because it allows to utilize the 2-mercaptobenzothiazole which, in the direct hydrolysis of Example 1, is lost in aqueous solution together with 2-aminothiophenolate in the form of sodium salts. In the further processing of the sodium salt of 2-aminothiophenol, the sodium salt is 207 10! 2-mercaptobenzothiazole as a defect, since after oxidation with hydrogen peroxide it contaminates 2,2 ' -diaminodiphenyl disulfide by the presence of 2,2 ' -dibenzothiazyl disulfide, which is insoluble in water. This results in a low degree of purity of the intermediate and, in addition, a reduction in the quality of the final 2,2'-dibenzoyldiamino diphenyl disulfide.

Alkaline digestion of benzothiazole followed by oxidation of 2-aminothiophene sodium salt and benzoylation of 2-2'-diaminodiphenyl disulfide in the presence of chlorobenzene under U.S. Pat. No. 108,079 is also practiced in industrial practice.

However, the disadvantage of this process is the fact that the benzoylation of 2,2'-diaminodiphenyl disulfide using chlorobenzene is carried out in the presence of a portion of the previous hydrolysis stages of benzothiazole and oxidation of 2-aminothiophenol hydrogen peroxide. Thereby, the manufacturing process is complicated, a series of reactions of the acylating agent with the contaminating water-soluble components, reduced yield and quality of the final product.

The above drawbacks are overcome by the preparation of 2,2'-dibenzoyldiaminodiphenyldisulfidualcalysis hydrolysis of benzothiazole, by oxidation of the resulting 2-aminothiophenol sodium salt with hydrogen peroxide and benzoylization of 2,2'-diaminodiphenyl disulfide with benzoyl chloride, the benzoyl chloride being benzoylized with benzoyl chloride. a solution of chlorinated organic solvent, preferably chlorobenzene, to separate the entire amount of contaminating components of the alkaline cleavage and oxidation in the aqueous specific layer. In order to provide the desired state, i.e., to convert 2,2'-diaminodiphenyl disulfide into a chlorobenzene solution without residue, it is required to solvent 1.3 to 1.5 parts by weight per 1 part by weight of 2,2'-diamino-diphenyl disulfide. .

After the addition of water and adjusting the temperature to 50 ° C, the acylation of 2,2'-diaminodiphenyl disulfide with benzoyl chloride in chlorobenzene is effected by simultaneously adding 1.05 to 1.1 moles, preferably 1.07 moles per liter, of the hydroxide solution to neutralize the hydrogen chloride formed. mole of benzoyl chloride used. The advantages of producing 2,2'-dibenzoyldiaminodiphenyl disulfide according to our approach are in a smooth process manageability, in high yields of pure component and in high quality final product. In the following two examples, we illustrate the advantages of our process for the production of 2,2'-dibenzoyldiaminodiphenyl disulfide in a form which explains the subject matter of the present invention but does not limit it. Example 1, a conventional procedure for the preparation of 2,2'-dibenzoyldiaminodiphenyl disulfide.

To a 4-necked 750 ml round-bottomed flask equipped with a stirrer, a thermometer, a back-cooler and a benzthiazole distilled dropping funnel, 233 g of 40% sodium hydroxide are introduced, which is heated to 130 ° C by an electric nest. Then go to

The 150 1OS flask was charged with 150.1 g, i.e., 1.11 moles of benzothiazole over 1 hour, and the mixture allowed to react for an additional hour under vigorous stirring. Upon completion of the hydrolysis, the unreacted benzothiazole (16.5 g, i.e. 0.12 mole) was distilled off by distillation and the resulting 2-aminothiophenol sodium solution was cooled to ambient temperature. To remove the inorganic liquids, the solution is filtered on a Buchner funnel and the concentration of sodium 2-aminothiophenol is adjusted to 10 wt% by dilution with water. The oxidation to 2,2 '- diaminodiphenyl disulfide is carried out at 10 to 15 ° C by uniformly adding 30% aqueous hydrogen peroxide solution in a total amount of 18.1 g / as 100 percent / 0.533 mol. The addition time of the hydrogen peroxide solution depends on the efficiency of the cooling mixture. After the oxidation is complete, the suspension of 2,2'-diaminodiophenyl disulfide from the mother liquors is separated by standing for one hour, one half of which, i.e. 658 g, is discharged and the same amount of water is added. To this treated suspension! 98 g of chlorobenzene is added to 2,2'-diaminodi-phenyldisulfide, which represents 0.85 parts by weight of 1 part by weight of 2,2 ' -diaminodiphenyl disulfide and 35.6 g of 40% sodium hydroxide, which will ensure that the pH of the next benzoylation will be pH the resulting reaction mixture.

The contents of the flask are then heated to 50 ° C, leaving a portion of 2,2'-diaminodiphenyl disulphide as insoluble matter and benzoylation of the mixture at 50-55 ° C for 2 hours followed by 1 hour recovery. The chlorobenzene used is distilled off after completion of the reaction by means of steam, the 2,2'-dibenzoyldiaminodiphenyl sulfide present is cooled to ambient temperature, filtered from the mother liquors, washed with water to remove inorganic salts and dried to constant weight at 70-80 ° C. 120 g of 2,2'-dibenzoyldiaminodiphenyl disulfide with a melting point of 135 DEG C. are obtained. The yield of the final product is 53.2 g by weight calculated on the converted benzothiazole. Example 2 comparing, documenting convenience? carrying out the preparation of 2,2'-dibenzoyldiamino-nodiphenyl disulfide according to the invention.

The weight of benzothiazole, the process of accepting hydrolysis and oxidizing the sodium salt of 2-aminothiophenol with hydrogen peroxide remains unchanged. To the resulting suspension! To the 2,2'-aminobiphenyl disulfide is added 157.5 g of chlorobenzene, which represents 1.36 parts by weight of organic solvent per 1 part by weight of 2,2'-diaminodiphenyl disulfide.

Then the contents of the flask are heated to 60 ° C, whereby 2,2'-diaminodi-phenyldisulfide is converted into the chlorobenzene solution without residue and after 15 minutes the stirring is stopped. By standing for half a hour at unchanged temperature, the chlorobenzene solution of 2,2'-diaminodiphenyldisulfide is separated from the aqueous layer containing the sodium methane salt and a number of the most soluble and inorganic components. Bottom layer of chlorobenzene-

Claims (1)

207 of the 2,2 ' -diaminodiphenyl disulfide solution is drained and placed in 1000 ml of 4 round-bottomed flasks equipped with a stirrer, thermometer, condenser, and dropwise addition of isoyl chloride and 40 percent sodium hydroxide. Water is added to the flask and the mixture is heated to 50 ° C. Acylation of 2,2 ' -diaminodiphenyl disulfide with benzoyl chloride is effected with simultaneous addition of 135.6 g (0.96 mol) benzoylating agent and 41.1 g (1.03 mol) sodium hydroxide as a 40 percent aqueous solution to form hydrogen chloride-forming reactions. . The addition of benzoyl chloride is carried out at 50-55 ° C for 2 hours followed by 1 hour recovery. Further work-up as described in Example 1 gave 205 g of 2,2'-dibenzoyldiaminodiphenyl disulfide, m.p. 141 ° C. The final product yield represents 90.9 weight per cent calculated on the reacted benzthiazole. OBJECT OF THE INVENTION A process for the preparation of 2,2'-dibenzoyldiaminodiphenyl disulfide by alkaline hydrolysis of benzothiazole, oxidation of sodium 2-aminothiophenol with hydrogen peroxide and benzoylation of 2,2'-diaminodiphenyl disulfide with benzoyl chloride in chlorobenzene with simultaneous addition of sodium hydroxide solution to hydrogen chloride neutralization characterized in that vodnejsuspenzi! diaminodiphenyl disulfide adds 1.3 to 1.4 parts by weight of chlorobenzene to 1 part by weight of 2,2 ' -diaminodiphenyl disulfide and benzoyl of 2,2 ' -diaminodiphenyl disulfide by benzoyl chloride is carried out after separation of the 2,2 ' -diaminodiphenyl disulfide solution from the aqueous layer of contaminating components resulting from the alkaline hydrolysis of benzothiazole and the oxidation of the sodium salt of 2-aminothiophenol.