Direct blue dyes from the condensation of diaminostilbenedisulfonic acid with N-alkyl or N-hydroxyalkyl-8-amino-1- naphthol-3,6-disulfonic acid

摘要

A new dye based upon N-alkylated or N-hydroxyalkylated 8-amino- 1- naphthol-3,6-disulfonic acid and 4,4'-diaminostilbene-2,2'-disulfonic acid, a procedure for synthesizing it and a procedure for utilizing it for coloring cellulosic substrates is disclosed. The naphthol compound is alkylated or hydroxyalkylated and coupled with the isolated tetrazonium salt of the diamine, and in a preferable embodiment sufficient of the sulfonic acid groups are neutralized to render the final dye water soluble. The procedure is preferably conducted in aqueous medium, and the substitution of the amino group of the naphthol compound is preferably effected with lower dialkyl sulfates or epoxides. The dye is particularly suitable for dyeing paper.