Abstract: This invention relates to a process for the production of an alkanesulfionic acid such as isethionic acid with a high purity in a high yield and at a low cost by oxidation of a (hydroxy)alkylmercaptan with hydrogen peroxide characterized in that a whole amount beyond a stoichiometric amount of a solution of hydrogen peroxide having a H.sub.2 O.sub.2 concentration of not less than 50% by weight is charged into a reaction vessel, said mercaptan is continuously fed at a temperature of 50.degree. C. or lower, aging is carried out, distillation with boiling is carried out and then the reaction mixture is contacted with an anion exchanger.

Abstract: According to this invention, there is provided an improved method of dyeing fibrous products characterized in that, in the dyeing of fibrous products using an oxidation-reduction dyeing type dye and an aqueous alkali solution of thiourea dioxide as a reducing solution, the reduction of the dye with the said aqueous alkali solution of thiourea dioxide is carried out in the presence of one or more substances selected from the group consisting of saturated aliphatic ketones having 3 to 10 carbon atoms, saturated aliphatic ketocarboxylic acids having 3 to 10 carbon atoms and alicyclic ketones having 3 to 10 carbon atoms.

Abstract: According to this invention, there is provided a method of dyeing fibrous products characterized in that, in the dyeing of fibrous products using an oxidation-reduction dyeing type dye and an aqueous alkali solution of thiourea dioxide as a reducing solution, the reduction of the dye with the said aqueous alkali solution of thiourea dioxide is carried out in the presence of one or more dialdehyde compounds selected from dialdehyde compounds represented by the general formulaOHC--R--CHO (I)in which R is a saturated or unsaturated aliphatic or aromatic organic compound radical.

Abstract: According to this invention there is provided a process for preparing thiourea dioxide characterized in that in the production of thiourea dioxide by the reaction of thiourea and hydrogen peroxide in an aqueous solvent, ammonium bicarbonate is added to the reaction solution at a proper time.

Abstract: According to this invention, there is provided a method of stabilizing an alkaline aqueous solution of thiourea dioxide characterized in that one or more substances selected from the group consisting of aliphatic ketones, alicyclic ketones and aliphatic dialdehydes are added to the said alkaline aqueous solution of thiourea dioxide.

Abstract: This invention provides a method of chemically polishing copper and copper alloys which comprises using a solution with one or more members selected from azoles having the structure represented by the general formulae ##SPC1##Wherein X, X' and X" represent any of hydrogen, amino, aminoalkyl containing 1-3 carbon atoms and alkyl containing 1-3 carbon atoms added to an acid aqueous solution of hydrogen peroxide containing hydrogen peroxide and sulfuric or nitric acid.

Abstract: This invention provides an improved method for stabilizing hydrogen peroxide in an acid aqueous solution of hydrogen peroxide containing copper ion capable of catalytically decomposing hydrogen peroxide. According to this invention there is used as a stabilizer in such method at least one glycol ether represented by the general formula R(OCH.sub.2 CH.sub.2).sub.n --OH wherein R is an alkyl group containing 1 to 4 carbon atoms and n is an integer from 1 to 2, and this stabilizer is added in the foregoing aqueous solution preferably in an amount of at least 0.1 g/l.