METHOD AND APPARATUS FOR PRODUCING PARACETAMOL FROM PARA-NITROSOPHENOL AND/OR PARA-NITROPHENOL IN ACETIC ACID MEDIUM Russian patent published in 2024 - IPC C07C231/02 C07C233/25 

FIELD: chemistry.

SUBSTANCE: invention relates to chemical engineering, particularly to a method of producing paracetamol from para-nitrosophenol and/or para-nitrophenol, as well as to an apparatus for realizing said method. Proposed method includes the following stages: a) preparing a solution of para-nitrosophenol and/or para-nitrophenol in acetic acid; b) feeding the solution from step a) into a reactor with an inert atmosphere while stirring and maintaining temperature in range from 40 to 55 °C; c) dosing zinc metal in the form of powder into the reactor at a controlled feed rate; d) stirring the reaction mixture until the reaction is complete while maintaining the temperature in range of 40 to 55 °C; e) cooling the reaction mixture to 3–7 °C for extraction of fine crystalline zinc acetate from reaction solution; f) removing the reaction mixture from the reactor into a separation device; g) separating solid zinc acetate as a retentate and a solution of para-aminophenol in acetic acid as a permeate; h) removing the solution of para-aminophenol in acetic acid from the separation device; i) feeding a solution of para-aminophenol in acetic acid from step h) into a reactor with a stirrer, forced maintenance of temperature in range from 10 to 140 °C and possibility of creating inert and/or rarefied atmosphere; j) boiling a solution of para-aminophenol in acetic acid at reduced pressure with distillation of part of watered acetic acid at temperature from 60 to 120 °C; k) boiling a solution of para-aminophenol in acetic acid at pressure of 2 to 3 atm. and temperature of 120 to 140 °C until complete reaction; l) cooling the reaction mixture to separate crystalline paracetamol from the reaction solution; m) removing the reaction mixture from the reactor into a separation device; n) separating the solid paracetamol from the liquid reaction mixture; o) washing paracetamol with acetic acid; p) drying of solid paracetamol and its unloading with obtaining of finished product.

EFFECT: providing a novel method of producing paracetamol, characterized by simplicity of implementation from hardware and technological points of view, availability and low cost of starting reagents and low power consumption, as well as providing high purity of the obtained end products without using additional labour-intensive purification steps.

19 cl, 3 dwg, 4 ex