C(=O)([O-])[O-].[Na+].[Na+].C(=O)(O)[O-].[Na+].[CH3:12][N:13]([CH3:24])[S:14][C:15]1[S:16][C:17]2[CH:23]=[CH:22][CH:21]=[CH:20][C:18]=2[N:19]=1.Cl[O-:26].[Na+].[OH-].[Na+].Cl[O-]>O>[CH3:12][N:13]([CH3:24])[S:14]([C:15]1[S:16][C:17]2[CH:23]=[CH:22][CH:21]=[CH:20][C:18]=2[N:19]=1)=[O:26]10 parts of sodium carbonate and 4 parts of sodium bicarbonate are added to a well stirred suspension of 63 parts 2-N,N-dimethylbenzothiazole-sulphenamide in 130 parts of water. 170 parts by volume of a solution of sodium hypochlorite titrating 177 g. of NaClO and 3 g. of free caustic soda per liter are then slowly introduced, in about 5 hours and keeping the temperature within the range from 25° C. to below 30° C. The excess of hypochlorite is controlled by starchiodide paper. After introduction, the mixture is stirred for a further hour. The creamy white precipitate obtained is filtered off, washed until the washings are neutral and dried at 60° C. The 2-N,N-dimethyl-benzothiazole-sulphinamide melting at 121°-122° C., free from dibenzothiazyl disulphide, is obtained with a yield of 90%.
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