10-Methyl-3-[3-(sodiosulfooxy)-1H-indol-2-yl]-11H-benzo[a]carbazol-4-ol (sulfuric acid sodium) salt

(a) in the presence of Pyridine , with Chlorosulfonic acid treatment ?C.I. Vat Black 2 leuco; (b) in the Pyridine with metal (such as copper, iron, zinc, etc) and Sulfur trioxide source (such as Sulfur trioxide, Chlorosulfonic acid or Methyl chlorosulfonate, etc.) processing ?C.I. Vat Black 2. The above two kinds of situation after alkaline, filter out insolubles, remove Pyridine and salting out.

blue light grey to blue black. Light gray powder. Soluble in water. Can be used for cotton fabric dyeing, affinity is low, add salt may help dye. Can also be used to direct, resist and discharge printing, discharge base color with light color effect is good.

Standard	Ironing Fastness	Chlorine bleach	Light Fastness	Mercerized	Oxygen bleach	Soaping
						Fading	Stain
ISO	4	4	4-5	3	3