SU943229A1 - Process for producing complex of dibromomalonitrile with potassium bromide - Google Patents

Description

The invention relates to a process for the preparation of a complex of dibromomalononitrile with potassium bromide, which is used as an intermediate in the synthesis of heterocyclic, biologically active compounds, dyes. .

A known method for the preparation of a complex of dibrmmolononitrile with potassium bromide by the halogenation of malonic dinitrile (1.5 mol) i-. bromine by-volume (3.05 mol) in an aqueous solution in the presence of potassium bromide (0.065 mol) at. The reaction time is 4.5–5 h. The precipitated solid is washed with ice water, sucked off and dried. The desired product is obtained in the form of light yellow crystals with a yield of 85-90%. An additional 2.5-5% of complex 1 is isolated from the mother liquor when standing for 1-2 days.

A disadvantage of the known modes is the length of the process and the efficiency of the product with bromine.

The purpose of the invention is to increase the.-Intensification of the process and the improvement of the quality of the spruce.

The goal is achieved by obtaining a complex of diboommalononitrile with potassium bromide by treatment; dinitrile; 1 Elonic acid in a solution of concentrated hydrogen bromide with potassium bromide

5 at a molar ratio of malonic acid dinitrile: potassium bromide / equal to 1: 1, under electrolysis conditions at a current of 1-1.2 A.

The target product falls in the form

10 crystals, which are washed with ice water and dried, after which white analytically pure crystals are obtained with a yield of 93–95%.

The process is carried out 1.2-1.5 hours.

15

The proposed method allows to obtain the target product free of bromine impurities while reducing the process time.

Claims (2)

Example 1. A solution of 6.6 g (0.1 mol) of malononitrile in 80 ml of concentrated hydro25 hydrocyanic acid is placed in an electrolytic cell equipped with a stirrer, a water-jacketed thermometer and platinum electrodes. 20MP (11.9 g, 0.1 mol) of a saturated potassium bromide solution is added to the resulting solution and the reaction mass is subjected to electrolysis at 1-1A 30 for 1.2 h. The reaction temperature is maintained at 12 ° C. In the process of electrolysis, the crystal of the target product falls out. After completion of the reaction, the crystals are filtered, washed with water / dried. The yield of the desired product in the form of white analytically pure crystals is 24 g (95%). Found,%: C 14.35; N 11.19; K 3.99; Br 70.77. Calculated,%: C 14.20; N 11.04; K 3.85; Br 70.90. At measure 2. Under the conditions of example 1 of b, b g (0.1 mol) of malononitrol, 80 ml of concentrated hydrobromic acid and 20 ml (11.9 0.1 mol) of a saturated solution of potassium bromide by the electrolysis of the reaction mass, 1: 2A, for 1.5 h at 8fC, 23.5 (93%) of the desired product is obtained. Found,%: C 14.30; N 11.15; K 4.05; Br 70.83., C aNgBr K. Calculated,%: C 14.20; N 11.04; K 3.85; Br 70.90. The advantage of the proposed CLEAN is the absence of the need to work with free bromine,. DETAILED DESCRIPTION OF THE INVENTION A method for producing a complex of dibromomalononitrile with potassium bromide from dinitrile malonic acid and potassium bromide in an aqueous medium at a low temperature, in order to increase the process intensification and improve the quality of the product, malonic acid dinitrile in solution concentrated hydrogen bromide is treated with potassium bromide at a molar ratio of dinitrile malonic acid: potassium bromide, equal to 1: 1, under electrolysis conditions at. and current 1-1,2A. Sources of information taken into account during the examination 1. Karboni R.A. Preparation of dibromalonitrile complex with potassium bromide. Synthesis of organic drugs. Sat 11, M., 1961, p. 54 (prototype).