METHOD AND APPARATUS FOR PRODUCING PARACETAMOL FROM PHENOL Russian patent published in 2024 - IPC C07C231/10 C07C233/25 B01J19/00 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method of producing paracetamol from phenol, as well as to an apparatus for realizing said method. Proposed method includes the following stages: a) separate simultaneous supply with a controlled rate of an aqueous solution of phenol, an aqueous solution of sodium nitrite and an aqueous solution of sulfuric acid and mixing them in a reactor filled with water or a recirculating mother solution; b) mixing the reaction mass obtained at step a) in a reactor to obtain a suspension from a mixture of para-nitrosophenol and crystalline sodium sulphate; c) removing the reaction mass from the reactor into a separating device, followed by separation of the solid residue of the mixture of para-nitrosophenol and sodium sulphate as the retentate and the mother solution as the permeate; d) preparing a solution of para-nitrosophenol in glacial acetic acid with simultaneous separation of insoluble sodium sulphate precipitate using a separating device; e) feeding the solution from step d) into a reactor with an inert atmosphere with mixing and forced maintenance of temperature in range from 40 to 55 °C; f) dosing zinc metal in the form of powder into the reactor at a controlled feed rate; g) stirring the reaction mixture until the reaction is complete while maintaining the temperature in range from 40 to 55 °C; h) cooling the reaction mixture to 3–7 °C for extraction of fine crystalline zinc acetate from reaction solution; i) removing the reaction mixture from the reactor into a separation device; j) separating solid zinc acetate as a retentate and a solution of para-aminophenol in acetic acid as a permeate; k) removing the solution of para-aminophenol in acetic acid from the separation device; l) feeding a solution of para-aminophenol in acetic acid from step k) into a reactor with a stirrer, forced maintenance of temperature in range from 10 to 140 °C and possibility of creation of inert and/or rarefied atmosphere; m) boiling a solution of para-aminophenol in acetic acid at reduced pressure with distillation of part of the watered acetic acid at temperature of 60 to 120 °C; n) 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; o) cooling the reaction mixture to separate crystalline paracetamol from the reaction solution; p) removing the reaction mixture from the reactor into a separation device; q) separating the solid paracetamol from the liquid reaction mixture; r) washing paracetamol with acetic acid; s) drying solid paracetamol and its unloading to obtain a finished product.

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

22 cl, 6 dwg, 1 ex