Condensation product of phenothiazine and p-nitrosophenol, process for producing the condensation product, process for producing sulfur dyes by using the condensation product and the produced sulfur dyes

摘要

The invention relates to a process for producing a condensation product from phenothiazine and p-nitrosophenol, which contains the indophenol S-oxide of the formula IMAGE, by reacting phenothiazine with p-nitrosophenol in sulfuric acid, the phenothiazine before or during the reaction with an additional oxidizing agent is oxidized. The condensation product obtained or the reduction product obtainable from the condensation product by reduction can be converted by sulfurization in the baking or cooking melt into sulfur dyes which provide green to black dyeings with good fastness properties on cotton and green to black polyamide.