A method for the production of the dye directly yellow (colour index 40000) in the form of stable, concentrated solutions, the resulting solutions and their use

摘要

The invention relates to a process for the preparation of the dyestuff Direct Yellow 11 directly in the form of stable concentrated solutions, in which caustic soda in aqueous solution is reacted, at a temperature from 40 DEG to 90 DEG C., with a solution containing 4-nitro-toluene-2-sulfonic acid, one or more alkanolamines, one or more alcohols containing an etheroxide function or a second alcohol function, then the caustic soda is neutralized by addition of sulfuric acid and the sodium sulfate thus formed is separated by filtration. The solutions obtained by the process according to the invention are particularly suitable for dyeing cellulosic materials and leather.