STABILIZED PEROXOMONOSULFURIC ACID SOLUTION AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To produce a peroxomonosulfuric acid solution stably preservable for a long period by regulating the peroxomonosulfuric acid prepared by reacting sulfuric acid with hydrogen peroxide at a specific molar ratio within a specified narrow pH range. SOLUTION: Sulfuric acid is reacted with hydrogen peroxide at a molar ratio of the sulfuric acid/hydrogen peroxide within the range of 2-5 to provide a stock solution of peroxomonosulfuric acid. The resultant stock solution is then diluted with water and regulated to 10-15wt.% concentration of the peroxomonosulfuric acid. The pH is subsequently regulated to afford a peroxomonosulfuric acid solution at pH 0.5-2.0. The regulated solution is then preferably heat-treated after the regulation of the pH to make the residual sulfuric acid disappear and improve the stability of the solution. The concentration of the peroxomonosulfuric acid is preferably regulated to 0.5-10wt.%. A homopolymer, a copolymer or a salt thereof comprising one or more selected from the unsaturated carboxylic acid group consisting of acrylic acid, methacrylic acid and maleic acid as a constituent unit, as necessary, is contained as a stabilizer in an amount of 50-2,000mg/L therein.