METHOD FOR OBTAINING PARA-AMINOPHENOL BY REDUCTION OF PARA-NITROSOPHENOL WITH AMMONIUM SULFIDE Russian patent published in 2023 - IPC C07C213/02 C07C215/76 

FIELD: chemistry.

SUBSTANCE: new method for the production of para-aminophenol by the reduction of para-nitrosophenol with ammonium sulfide by the reduction of para-nitrosophenol. This method includes the following steps: a) preparing a solution of p- nitrosophenol in an aqueous ammonia solution; b) providing an aqueous solution of ammonium sulfide; c) simultaneously feeding the solutions from steps a) and b) with a flow ratio corresponding to a molar ratio of p- nitrosophenol to (NH₄)₂S from 1:1.5 to 1:2.5 into an inert atmosphere reactor with stirring, and forced maintenance of temperature in the range from 40 to 50°C; d) after complete addition of the solutions from steps a) and b) evacuation of the reaction mixture until the complete removal of ammonia while forcibly maintaining the temperature in the range from 40 to 50°C; e) removing the vacuum and cooling the reaction mixture to 18-20°C; f) withdrawing the reaction mixture from the reactor into a nutsche filter; g) separating the solid para-aminophenol on the filter and washing it with water; h) unloading para-aminophenol from the nutsche filter and drying it at a temperature not exceeding 55°C with the receipt of the finished product.

EFFECT: cheap and readily available reagents, as well as cost-effective waste disposal, allows, without the use of special equipment, to obtain and isolate the product, that are hardwarily and technologically simple, providing high purity and high yield, and also guarantees a product that is stable upon further drying, transportation and storage.

7 cl, 1 dwg, 1 ex