Industrial Production Method Of Sulfur Dyes

There are two industrial production methods of sulfur dyes:
(1) Baking method, the amines, phenols or nitro of raw aromatic hydrocarbons are baked with sulfur or sodium polysulfide at high temperature to prepare yellow, orange and brown sulfur dyes.
(2) Boiling method, the amines, phenols or nitro of raw material aromatic hydrocarbons and sodium polysulfide are heated and boiled in water or organic solvents to prepare black, blue and green sulfur dyes.