METHOD FOR PURIFYING SULFAMIDE

PURPOSE:To easily obtain high purity sulfamide useful to produce intermediates of dyes and pharmaceuticals by bringing a soln. of sulfamide contg. impurities in an org. solvent into contact with a specified inorg. solid absorbent. CONSTITUTION:Sulfamide contg. impurities is dissolved in a polar org. solvent such as methyl acetate, acetonitrile or 1,4-dioxane to prepare a soln., and one or more kinds of inorg. solid absorbents selected among activated alumina, zeolite and a molecular sieve each having >=7 pH surface acidity measured with a Nishicater indicator are added to the soln. The soln, is brought into contact with the adsorbents by stirring to allow the impurities to be adsorbed on the adsorbents. The adsorbents are then filtered off, the resulting filtrate is heated under reduced pressure to remove the org. solvent, and the remainder is vacuum-dried to obtain high purity sulfamide.