A method for producing a salt of acrylamide-2-methylpropanesulfonic acid (A), a method for producing acrylamide-2-methylpropanesulfonic acid (A) or a salt thereof, and a copolymer using the same

摘要

The invention relates to a method for producing salts of acrylamido-2-methylpropane sulfonic acid (A), comprising the following steps: a) producing a solution of a contaminated salt of acrylamido-2-methylpropane sulfonic acid (A) in a water-free, organic solvent (L) using at least one basic component (B) selected from the group comprising alkali metal oxides, alkaline-earth metal oxides, alkali hydroxides, alkaline-earth metal hydroxides, and amines of general formula (I) NRa Rb Rc (I), wherein the groups Ra, Rb, and Rc mean the following independently of each other: hydrogen, C1-C4 alkyl, hydroxy C1-C4 alkyl, or C1-C4 alkoxy, wherein the molar ratio of compound (A) to basic component (B) is preferably 1:1 to 1:3; b) optionally partially removing the organic solvent (L) at a pressure in the range of 0.001 to 2 bar (abs); c) recovering the dissolved salt of compound (A) by crystallization or precipitation, by changing the temperature and/or the pressure and/or the concentration of the salt in the solution; d) optionally drying the purified salt of acrylamido-2-methylpropane sulfonic acid (A). Said method according to the invention leads to salts that are poor in byproduct and especially suitable for polymerization.