Benzothioxanthene dyes with improved application and toxicological properties.

摘要

A method for preparing a dye composition noncorrosive benzothioxanthene, no mutagenic and no sensitizer, containing at least 99.0% by weight of a compound of formula (1) and not more than 0.5% by weight of a compound of formula (2) wherein R1 and R2, independently, are hydrogen, methyl, ethyl, methoxy, ethoxy or chlorine, comprising condensation of 2-aminothiophenol with March 1-bromobenzantrona having a maximum of 0, 5% by weight of a dibromobenzanthrone, especially 3,9-dibromobenzanthrone, followed by diazotization and cyclization, wherein the 3-bromobenzantrona having a maximum amount of 0.5% by weight of dibromobenzanthrone is obtained by dispersing and washing it in a solvent organic, followed by filtration, and the organic solvent is a dialkylated carbonamide, such as dimethylformamide, dimethylacetamide, N-methylpyrrolidone, N-methyl-piperidone-2, N-formyl-morpholine, dimethylsulfoxide, sulfolane, acetonitrile, propioni trilo, or a mixture thereof. ++