GB738407A - A process for the manufacture of permonosulphuric acid - Google Patents

Abstract

Solutions containing permonosulphuric acid are manufactured by mixing regulated amounts of concentrated sulphuric acid and hydrogen peroxide under such conditions as to produce a mixture of permonosulphuric acid, sulphuric acid, water and hydrogen peroxide, cooling the mixture to inhibit further reaction, and substantially immediately diluting the mixture with water to produce an aqueous solution containing not more than 15 per cent permonosulphuric acid. The hydrogen peroxide is mixed with an equal or larger volume of sulphuric acid and the reaction may be effected continuously by running together streams of hydrogen peroxide and sulphuric acid at uniform velocity, preferably in the volume ratio 1 to 3 or 4. To effect reaction to permonosulphuric acid, the reaction mixture should reach at least 50 DEG C., by the exothermic effect of the dilution of the sulphuric acid, although with acid of less than 88 per cent concentration, e.g. between 76 and 88 per cent, external application of heat may be necessary. This temperature rise may be obtained by provision of a reaction time of a few seconds before cooling, although with less than 50 per cent concentration hydrogen peroxide the reaction time is not necessary and the mixing may take place in the cooler. The dilution may be effected by passing the cooled mixture into a tank of water containing ice, or by pumping water into the lower portion of the water-cooled cooler, or two coolers may be used with the second being used for dilution. Dilution should be carried out with soft water. The product consists of up to 15, preferably 2.8-15 per cent, permonosulphuric acid, up to 15, preferably 0.2-1.1 per cent hydrogen peroxide, up to 25, preferably 4.8-13 per cent sulphuric acid, balance, preferably 81-88 per cent water and may be used for bleaching.