With a few exceptions, sulfur dyes are used for dyeing cellulosic fibres. They are insoluble in water and are reduced to the water-soluble leuco form for application to the substrate by using sodium sulfide solution. The sulfur dye proper is then formed within the fiber pores by atmospheric or chemical oxidation. Sulfur dyes constitute an important class of dye for producing cost-effective tertiary shades, especially black, on cellulosic fibers. One of the most important dyes is C. I. Sulphur Black 1, prepared by heating 2,4-dinitrophenol with sodium polysulfide.
[1] C. Heid, K. Holoubek, R. Klein, “100 Jahre Schwefelfarbstoffe” [100 Years of Sulfur Dyes], Melliand Textilber. Int. 54 (1973) 1314-1327.
[2] W. Zerweck, H. Ritter, M. Schubert, “Zur Konstitution der Schwefelfarbstoffe” [On the Constitution of Sulfur Dyes], Angew. Chem. 60 (1948) 141-147.
[3] J. Marek, D. Markova, “Uber Schwefelfarbstoffe I, Zur Konstitution des lichtechten gelben Schwefelfarbstoffs Immedial-Lichtgelb GWL” [On Sulfur Dyes, I, On the Constitution of the Lightfast Yellow Sulfur Dye Immedial Supra Yellow GWL], Collect. Czech. Chem. Commun. 27, 1533-1548 (1962).
[4] R. Gnehm and F. Kaufler, Ber. dtsch. chem. Ges. 37 (1904) 2617-2623, 3032-3033.