Intermittent preparation method of 1-methyl-4-methylsulfonylbenzene

The invention discloses an intermittent preparation method of 1-methyl-4-methylsulfonylbenzene. The method comprises the following steps of (1) adding sodium bicarbonate or sodium carbonate, sodium sulfite, p-toluenesulfonyl chloride and a catalyst into water, and reacting to obtain a feed liquid; (2) feeding the feed liquid into a reaction kettle, introducing methane chloride gas, and reacting the methane chloride gas with the feed liquid to obtain a reaction liquid; transferring the reaction liquid to a reaction liquid kettle, enabling methane chloride dissolved in the reaction liquid to overflow through pressure reduction, and meanwhile, sending the methane chloride in the reaction liquid kettle back to the reaction kettle for the next reaction liquid preparation process; and (3) outputting the reaction liquid in the reaction liquid kettle, carrying out heat preservation, regulating the pH value to 9-12, cooling to crystallize and separate out a product in the reaction liquid, carrying out solid-liquid sep