Continuous production method of 2-methyl-4-isothiazolin-3-one

The invention relates to a continuous production method of 2-methyl-4-isothiazolin-3-one, and belongs to the technical field of chemical industry. According to the method, continuous production is adopted, high-purity 2-methyl-4-isothiazolin-3-one can be obtained, the production yield is high, the production process is easy to control, the energy consumption is reduced, the production efficiency is improved, and meanwhile, the production process is safe and controllable. The method comprises the following steps: 1) preparing N, N '-dimethyl-3, 3'-dithiodipropionamide, chloroform and N, N-dimethylformamide to form a mixed solution; 2) pumping the mixed solution and chlorine to react in a first-section tubular reactor; (3) enabling a reaction material to enter a second-section tubular reactor with a jacket for reaction; (4) enabling a reaction material to enter a third-section tubular reactor with a jacket for reaction; and 5) after the tube continuous reaction is finished, directly feeding a reaction liquid in