SU696007A1 - Method of preparing 4 -aminodiphenylamine - Google Patents

Description

(54) METHOD OF OBTAINING 4-A) UINODIPHENYLAMINE

. 1- The invention relates to a process for the preparation of 4-aminodiphenylamine, which finds use as an intermediate in the production of a series of chemical additives to polymeric materials, as well as in the chemistry of dyes. A known method for producing 4-am. Diphenyl amine by reducing the sodium salt of 4-nitrosodiphenylamine with hydrogen in an aqueous solution with an organic water-immiscible solvent in the presence of hydrogenation talizators (palladium carbonate or platinum oxide) using an initial salt in an amount of 50-100 g per 1 g of catalyst 1. Process temperature 20-1OO C, hydrogen pressure 3.5-35 atm, reaction time 3-12 hours. Catalyst consumption 5.5 kg per 1 ton of the desired product. Process performance up to: 110 g / l hour. output 4-aminodiphenylamine with so pl. 63-67 ° C to 97%. The disadvantages of this method are relatively low productivity of the process, a significant consumption of expensive catalysts. The relatively low quality of the whole product (when 4-aminodiphenylamine is used as the semi-product in the synthesis of diaphene (OP requires a product with a minimum temperature of 70 ° C). The aim of the invention is to increase the productivity of the process while reducing the consumption of the catalyst and improving the quality of the product. The aim is to restore the sodium salt of 4-nitrosodiphenylamine to In an aqueous solution, methanol is added as an organic solvent with a content of 4-nitrosodiphenylamine sodium salt of 0.011-0.022 g per 1 g of catalyst. René nickel is used as catalyst in a reaction mixture of 40-60 g / l. Process preferably carried out at a temperature of 60-70 ° C and a hydrogen pressure of 40-100 atm. The proposed method is carried out in an autoclave equipped with an aeration mixer, filters and a device for continuous input of the initial thief and withdrawal of hydrogenate. The process is conducted at a temperature of 60-70 s, which is maintained by the heat of reaction, and a hydrogen pressure of 40100 atm. The contact time of sodium salt of 4-nitrosodiphenylamine with kataieators) m. 10-20 min. The active catalytic converter is maintained for 420,720 hours of continuous operation, after its catalyst is replaced with a new one. The output of 4-Ni6p6diphenylamine with so pl. 73-74 С to 97.4%. Catalyst consumption 0.142-0.2 kg per 1 ton of product. Productivity of process 0,478 0, 600 kg / l.ch ..

 The proposed method provides. the significantly higher productivity of the process and the use of a cheaper hydrogenation catalyst (Rene nickel) to reduce its consumption to such an extent that it eliminates the need for its regeneration. The method allows, without reducing the yield of the target product, to improve its quality. In the process, there is no need for special heating when the realization mixture is cooled, since under these conditions the process temperature is due to the heat generated during the reaction.

Example 1. In an autoclave with a capacity of 2 liters, equipped with an aeration mixer, a built-in filter having a surface of 150 cm and a pore size of less than 5 microns, a urs-s probe adjusted to a working volume of .25 l is charged with a water Rene nickel (50 g in terms of metallic nickel) and 400 ml of 80% methanol.

Create a hydrogen pressure in the autoclave 40-100 atm and include a mixer. An initial solution prepared by mixing 20% aqueous pacTBopk sodium salt of 4-nitrosodiphenylamine is charged into the feed tank. (18% in terms of 4-nitrosodiphenylamine) with 80% methanol in relation to scientific research institute 1: 1 by volume. The content of 4-nitrosodiphenylamine sodium salt in this solution is 11.8.% (10.6% in terms of 4-nitrosodiphenylamine, d 4 ° 1,016). A dosing pump is turned on and the stock solution is fed into the autoclave at a rate of 6.1 kg / h (6 l / h). The hydrogenate continuously exits the autoclave through a built-in filter and a control valve, operating from a level sensor and supporting a working volume of 1.25 l in the autoclave. The temperature in the autoclave rises within 5–10 min to 60–70 s due to the heat of hydrogenation. The concentration of catalyst in the autoclave is 40 g / l. The content of unreacted 4-nitrosodiphenylamine in hydrogeneate is 0.865 g / l (0.022 g per 1 g of catalyst), the content of 4-aminodiphenylamine is 99.66 g / l. Hydrogenate bes1 .9y, on the air quickly turns blue. Converse: 4-nitroso diphenylamine to 4-aminodiphenylamine 99, 2%. -Performance of the process according to the hydrogenation stage of 0.478 kg of 4-aminodiphenylamine per hour with 1 liter of reaction volume. After 427 hours, the temperature in the autoclave begins to decrease, the color of the hydrogenisate becomes light green first and then orange. Hydrogenation ... stops. Methanol is distilled off from hydrogenate, then molten 4-aminodiphenylamine is separated from water in a separating funnel and distilled. Yield according to the isolation and purification step. 98-aminodiphenylamine 98%. The total yield of 4-aminodiphenyls "and so so pl. 73-74c is 97.2%. Catalyst consumption in terms of 1 ton of distilled 4-aminodiphenylamine 0.200 kg.

Example 2. Under the conditions of example 1, the continuous hydrogenation of the sodium salt of 4-nitrodiphenylamine is carried out at a concentration of rene nickel of 50 g / l. The original yy, the target is served in an autoclave at a speed of 6.1 kg / h (6 l / h). The content of unreacted .4-nitrosodiphenylamine in the reaction zone is 0.650 g / l (0.013 g per 1 g of catalyst). The content of 4-aminodiphenylamine in hydrogenation 99.86 g / l. Consex 4-nitrosodiphenylamine in 4-aminodiphenylamine 99 ,, 4%. The productivity of the process according to the hydrogenation stage is 0.479 kg / h with 1 liter of the reaction volume of the autoclave.

After 720 hours, the temperature in the autoclave begins to decrease, the color of the hydrogenate becomes green. The hydrogenation is stopped. The isolation and purification of 4-aminodiphenylamine is carried out as described in Example 1. The yield of distilled 4-aminodiphenylamine with mp. 73-74 ° C is 97.4%. Catalyst consumption 0.146 kg per 1 ton of purified product.

Example 3. Under the conditions of Example 1, continuous hydrogenation of the sodium salt of 4-nitrosodiphenylamine is carried out at a Rene nickel concentration of 60 g / l. The original solution is fed into the autoclave at a speed of 7.64 kg / H (7.5 l / h). The content of unreacted 4-nitrosodiphenylamine in the reaction zone is 0.660 g / l (0.011 g per 1 g of nickel. Rene). The content of 4-aminodiphenylamine in the hydrogenation product is 99.66 g / l. Conversion of 4-nitrosodiphenylamine to 4-aminodiphenylamine 99.4%. The productivity of the process according to the hydrogenation stage is 0.600 kg per -1 l of the reaction volume of the autoclave. After 720 h. Hydrogenate acquires a green color. Hydrogenation is stopped. Isolation and purification of the finished product is carried out as described in Example 1.

Claims (2)

Yield 4-am 11 Nodiphenylamine with m.p. 73-74 ° C is 97.4%. Catalyst consumption 0.142 kg per 1 ton of finished product. Example 4 (comparative). Under the conditions of Example 1, continuous hydrogenation of 4-nitrosodiphenylamine sodium salt was carried out at a Rene nickel concentration of 25 g / l. The initial solution was fed at a rate of 12 l / h. The temperature in the autoclave rises, up to. The color of hydrogenate is orange. The conversion of the sodium salt of 4-nitrosodium phenylamine to 4-aminodiphenylamine is 77%. The content of sodium salt of 4-nitroodiphenylamine in the reaction zone is 25 g / l or in terms of 1 g of catalyst 1 g / g. After 3 hours, the temperature in the autoclave begins to fall and the hydrogenation is stopped due to clogging of the filter that crystallized out at 4-aminodiphenyl, amine. Isolation of the finished product was carried out as described in Example 1, Yield of 4-aminodiphenylamine with m.p. 73-74 seconds is 70%. Catalyst consumption 8.5 kg per 1 ton of finished product. Claims 1. A method for producing 4-aminodiphenylamine by reducing the sodium salt of 4-nitrosodiphenylamine with hydrogen in an aqueous solution with the addition of an organic solvent in the presence of a hydrogenation catalyst at elevated temperature and pressure, liberating the desired product, so that in order to increase the productivity of the process, improve the quality of the product, the process is carried out with the addition of methanol as an organic solvent, Rene nickel as a catalyst with its content in the reaction ionic mixture equal to 40-60 g / l, and sodium salt of 4-nitrosodiphenylamine per 1 g of catalyst in the amount of 0.011-0.022 g 2. Method PO.P.1, characterized in that the process is carried out at a temperature of 60-70 ° C and a hydrogen pressure of 40-100 atm. Sources of information taken into account in the examination 1. Patent of Germany No. 1266766,: CL. 12 (, 3, publ.22.11.68.