Basic colouring matters are made readily soluble in water by admixture of the free base with sulphamic acid, or by mixing a salt of the free base with a salt of sulphamic acid and, if necessary, drying, or by conversion of the free base into a sulphamate by reacting it with sulphamic acid or by reacting a salt thereof with a soluble salt of sulphamic acid. In examples: (1) Rhodamine B base powder is mixed with powdered sulphamic acid; (2) Victoria blue B or R base is ground with sulphamic acid; (3) Acridine orange base powder is mixed with powdered sulphamic acid; (4) the free base of the condensation product from 4 : 41 - di(dimethylamino)benzophenone and p-tolyl-m-phenetidine is mixed with sulphamic acid, the mixture is treated with hot water and filtered and the sulphamate of the dyestuff is crystallized from the filtrate; its aqueous solution gives reddish blue shades on tannin-mordanted cotton; (5) the hydrochloride of the condensation product from 4 : 41 - di(dimethylamino)benzophenone and a :b - dinaphthylamine is mixed with ammonium sulphamate; an aqueous solution of the mixture gives greenish blue shades on tannin-mordanted cotton; (6) and (7) Methyl violet 2B base and Methyl violet R base are ground with sulphamic acid.
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