The invention discloses a preparation method of high-content thiodicarb, and relates to the technical field of
chemical synthesis. The method comprises the following steps: generating methylformamide thiamidine by taking N-methylformamide and
sulfur dichloride as raw materials, carrying out
condensation reaction on the methylformamide thiamidine and
methomyl as raw materials under the action of a catalyst to generate a
mixed solution containing thiodicarb, adding water into the
mixed solution, conducting cooling to obtain a solution and crystals, filtering the solution and crystals, washing the filtered crystals, centrifugally filtering the
crystal and a detergent, and
drying the centrifugally filtered
crystal to obtain thiodicarb with the content of greater than or equal to 98.0% and the total yield of greater than or equal to 95.0% in terms of
methomyl. According to the method provided by the invention, the safety occupational
health hazard risk is reduced, the process is
safer, the operation is convenient, the use of
pyridine is avoided, the foul
odor on the production site is avoided, the
environmental protection pressure is relieved, the production cost is reduced, the product quality and yield of thiodicarb are remarkably improved, and the thiodicarb reaches the export standard.