Synthesizing method of 2-acrylamide-2-methylpropane sulfonic acid

The invention provides a synthesizing method of 2-acrylamide-2-methylpropane sulfonic acid. The synthesizing method includes a continuous reaction. According to the continuous reaction, the mass ratio of acrylonitrile to concentrated sulfuric acid to isobutylene to acetic anhydride is (593-848):156.8:89.6:1 according to the adding amount. The prepared product is high in yield, wherein the yield is 88.0%-90.5%; the prepared product is high in purity, wherein the purity is 99.55%-99.75%; the chromaticity (platinum-cobalt number) of the prepared product is 5. Raw material consumption is low, the consumption of acrylonitrile is 320 kg/t; the consumption of isobutylene is 310 kg/t; the consumption of concentrated sulfuric acid is 560 kg/t; the consumption of acetic acid is 60 kg/t. The melting range of the prepared product is 186.5 DEG C-187.5 DEG C; the acid value of the prepared product is 270.0-272.0 mgKOH/g.