SU844616A1 - Method of producing 2-methylindoline - Google Patents

Description

This invention relates to a process for the preparation of 2-methylindolene used as an intermediate in the synthesis of dyes and other products of the national household. There is a known method for producing 2-methylende lnna, which consists in that 2-methylindole is subjected to electrochemical reduction in aqueous sulfuric acid, catholyte, containing 2-methylindole, is introduced into a circular cycle through the electrolyzer 11 cascade column. The yield of the target product 91 / about l. The pedostat as this method refers to the complex instrumentation and low input of the 2-methyl-dd. In the low solubility of 2-methylindole in aqueous sulfuric acid, electrolysis is carried out in the presence of an organic solvent, which requires its distillation after electrolysis and reduces the yield of non-bulk acid product. When conducting electrolysis without an organic solvent, the temperature must be maintained above the melting point P1 of 2-methylindole, which significantly complicates the industrial development of this method. In addition, in the case of nuit {La lizacin with aqueous sulfuric acid ammonia water, wastewater is formed, containing ammonium phosphate, utilized in which; x zatrudiyeya. The purpose of the invention is to simplify the process and increase the yield of the target product. This goal is achieved by the fact that, according to the method for producing 2-methylgoline, 2-methylindole is subjected to electrochemical reduction in 2-20 wt. % solution in hydrochloric acid in the presence of antifoaming agents, such as csc tributyl phosphate, polyphenylsiloxane. Lead is used as a cathode, titanium-based ruthenium anode is used as a cathode, and ceramics or cation-nitrite membranes are used for diaphragms. Anolyte - 2-15% sulfuric acid.

After electrolysis, the reaction mass is neutralized with an aqueous solution of sodium hydroxide and separated by 2-megylindole by steam distillation or decantation, followed by distillation in vacuo. The resulting aqueous solution of sodium chloride as waste is directed to the production of chlorine and sodium hydroxide. The yield of 2-methylvdoline 98%. content of the main substance 99%. Current output 50/0.

Example. In order to obtain a catholyte, 32 g of 2-methyl or schola are dissolved in 2OO g of 2 5-hydrochloric acid. Catarate .araT in the cathode space of the cy. And schraic glass electrolyzer, add OD weight,% of tributyl phosphate (catholyte slurry is supported).

Lead cathode, Caramiches diaphragm, L) Yulite - 1O% sulfuric acid. The current density is 7.5 A / dm, the voltage is 7.5 V. The current consumption is 2OO / 0 per theory.

After the end of the electrolysis, the solution is poured into a solution cooled to water at a volume ratio of solution: water-1: 3.5. Unreacted 2-methylbdd precipitates (about 0.001 g. After filtration, the filtrate is neutralized to pH 6 with caustic soda, 2-methyl indoline is separated and subjected to distillation in vacuum. 31.4 g of 2-methyl indoline is obtained. The yield from theory is 98.1%. Content of the main substance in the product is 99.2%. Current output is 5O%.

Example 2 To obtain a catholic, 158 g of 2-methyl Zdol is dissolved in 2 liters of 22 / hydrochloric acid, 2 g of polyphenylsiloxane is added and loaded into the cathode space of the electrolyzer.

Filter press type electrolyzer, teflon.

The diaphragm is a cation exchanger, the anode is oxidized (titanium-based), the cathode is lead, the anolyte is 3% sulfuric acid. The catholyte and anolyte are in a cycle (cell, cooler, phase separator cell). Current density 15 A / dm. Voltage 8.5 V. Temperature, Current consumption 200% of theory.

After completion of the electrolysis, the solution is diluted with water (1: 4). Filtered 2-methylitsaol (traces). After filtration, the filtrate is neutralized with caustic soda to a pH of 7 and subjected to overheated steam. 155 g of 2-methylindoline is obtained from the epaulette by salting out with sodium chloride. from theory 98.4%, current output 50%.

Claims (2)

Invention Formula 1 The method of producing 2-methylindoline by electrochemical reduction of 2methylindo. Sy in the form of solution in mts} of mineral acid, is also distinguished by the fact that, in order to simplify the process and increase the yield of the target product, the reduction of 2-met 1 Shpdol is carried out in Form 2-2O weight,%. solution in hydrochloric acid in the presence of antifoam, 2. The method according to p. 1, about the tl and h and y and that the use of tributyl phosphate or polyphenylene-o-ocean as a defoaming agent. Sources of information taken into account in the examination 1. For the application of the Federal Republic of Germany No. 24О3446, cl. With O7D 029/04, 1974 (prototype).