PRODUCTION METHOD OF METHALLYLSULFONATE

PROBLEM TO BE SOLVED: To provide the production method of a methallylsulfonate which comprises a step of reacting isobutene with a sulfur trioxideLewis base complex, a step of neutralizing the resulting reactant mixture with a base and a step of separating methallylsulfonate. SOLUTION: Methallylsulfonate is obtained by following steps: (a) isobutene is sulfonated with the sulfur trioxide Lewis base complex at -20 deg.C to 80 deg.C under a pressure of 1 to 15 bar, (b) the reactant mixture thus obtained is diluted with water, (c) the reactant mixture thus diluted is neutralized to a pH of 6 to 8 with the base, and (d) methallylsulfonate is obtained from the reactant mixture thus neutralized. In this production method, the loss of a chelating agent is reduced, the contents of by-products are reduced, and low-cost contact furnace gases can be used as the sulfur trioxide source for the production of the sulfur trioxide Lewis base complex.