a. Add 600-800 parts of ammonium bicarbonate and 500-700 parts of acetone cyanohydrin to water and stir to fully dissolve, and then seal it when heated to 10;
b. Then pass 30 to 50 parts of ammonia into the substance made by step a, slowly increase the temperature to 50 to 65 , constant temperature for 1 to 2 hours, and stirring;
c. The substance made by step b was heated to 7585, induced air for 3050 minutes, then cooled to room temperature and filtered, i.e., the crude dimethylhydantoin and the mother liquor were made;
d, the dimethylhydantoin crude product 950 to 1150 parts produced by step c is put into 150 to 300 parts of water and 700 to 900 parts of mother liquor mixture, stirring while putting, heating to 80 to 98 and then adding 3 to 8 parts of activated carbon, decoloration for 20 to 40 minutes, filtration to remove the activated carbon, and then cooled to crystallize, centrifugal filtration and drying, i.e., the finished product of dimethylhydantoin is produced.
