Improvements in tetrakisazo dyes, and the process of manufacture

摘要

265,553. Newport Co., (Assignees of Oesch, J. B.). Feb. 6, 1926, [Convention date]. Tetrakisazo dyes are made by coupling a diazotized aminoazo body of the benzene series, containing one or two sulphonic groups and two to four methyl groups, with m-toluidine, rediazotizing and again coupling with m-toluidine, and rediazot.izing the trisazo dye thus formed and coupling with 1-phenyl-3-methyl-5-pyrazolone or a substitution product, particularly a sulphonic acid thereof. The products dye unmordanted cotton orange to brown shades of great fastness to light. In an example, sodium aminoazotoluene disulphonate used as the first component, and 1- p-sulphophenyl-3-methyl-5-pyrazolone (sodium salt) as end component. Strong reducing agents split up the dyestuff at the azo groups, yielding sodium 2-toluidine-5-sulphonate, sodium 2 : 5- diaminotoluene-3-sulphonate, methyl-p-phenylenediamine, and 1-p-sulphophenyl-3-methyl-4- amino-5-pyrazolone. Specifi cation 208,265 is referred to.