A new copper-containing disazo dyestuff

摘要

The invention comprises a dyestuff of formula FORM:0744930/IV(c)/1 made by coupling tetrazotised 3, 31-dimethoxy-4, 41-diphenyl with one molecular proportion of each of the appropriate naphthol sulphonic acids and treating the disazo dyestuff thus obtained with copperyielding agents. The coupling should be alkaline and advantageously the first coupling is effected in the presence of sodium carbonate and the second in a medium containing sodium carbonate or ammonium hydroxide and pyridine. Coppering may be effected with a hot ammonical solution of a copper salt. The dyestuff dyes celluosic fibres in blue shades. An example of the preparation is provided.