NEW METHOD FOR PRODUCING 2-ACRYLAMIDO-2-METHYLPROPANESULFONIC ACID Russian patent published in 2021 - IPC C07C303/02 C07C309/15 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for producing 2-acrylamido-2-methylpropanesulfonic acid, including following successive stages: 1) mixing acrylonitrile with a compound providing SO₃ selected from fuming sulfuric acid or a mixture of sulfuric acid and fuming sulfuric acid at a temperature of -40 to 30°C for 1 to 120 minutes to obtain a sulfonated mixture; 2) bringing into contact and mixing isobutylene and the sulfonated mixture at a molar ratio of SO₃ and isobutylene ranging from 0.2:1 to 2:1 and a molar ratio of acrylonitrile and isobutylene ranging from 3:1 to 60:1 at a temperature ranging from -40 to 100°C for a period of time ranging from 5 to 300 minutes to obtain a reaction mixture; 3) separating the reaction mixture into a solid/liquid phase and separating solid particles contained in the reaction mixture in the form of a composition 1, in which solid particles make up from 50 to 99% by weight of the composition 1; 4) mixing the composition 1 obtained at stage 3) with an aqueous solution A, which is water or a liquid phase from stage A containing water, acrylonitrile, sulfuric acid and 2-acrylamido-2-methylpropanesulfonic acid or water and 2-acrylamido-2-methylpropanesulfonic acid, for from 10 minutes to 12 hours at a temperature of 5 to 40°C to obtain a suspension 1 of 2-acrylamido-2-methylpropanesulfonic acid; 5) separating the suspension 1 into a solid/liquid phase and separating crystals in the form of a composition 2, in which crystals make up from 40 to 91% by weight of the composition 2.

EFFECT: technical result is obtaining a new method for producing 2-acrylamido-2-methylpropanesulfonic acid.

15 cl, 4 ex