| 摘要 |
PURPOSE: Provided is a process for reducing dyes of the group consisting of sulfur and vat dyes. The reduction is carried out in an aqueous alkali medium using isomaltulose or a mixture containing isomaltulose as the reducing agent. CONSTITUTION: Dyes of the group consisting of sulfur and vat dyes are reduced by using a reducing agent comprising 10-90wt.% of isomaltulose, one of aqueous alkaly medium, and mixture of isomaltulose and other reducing sugar. Thereby, water insoluble type of sulfur and vat dyes are reduced into water soluble type. Wherein, sulfur dye is prepared by boiling water treatment of compounds in polysulfides or sulfurs and vat dye is an antraquinone derivative. The reduction process is proceeding in the aqueous solution of pH 11-12.5, at over 50°C, preferably 80-100°C.
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