METHOD OF PREVENTING COLORING IN HYDANTOIN PRODUCTION

PURPOSE:To obtain hydantoin while preventing coloring, by reacting glycinonitrile with ammonium bicarbonate, ammonium carbonate, or ammonia and carbon dioxide or their mixture in the presence of a sulfite or an acidic sulfite in water or in an aqueous solvent. CONSTITUTION:In reacting glycinonitrile with ammonium bicarbonate, ammonium carbonate or ammonia and carbon dioxide or their mixture in water or an aqueous solvent, 0.001-0.3mol, preferably 0.01-0.05mol based on 1mol glycinonitrile of a sulfite or an acidic sulfite (especially sodium sulfite, potassium sulfite, acidic sodium sulfite, acidic potassium sulfite is preferably inespensive and easily handleable) is added to the reaction mixture, and coloring of the reaction solution is prevented, to produce hydantoin. USE:An intermediate for medical drugs and agricultural chemicals.