tetrasodium 3-[(9,10-dihydroxy-1-anthryl)amino]-10,15-dihydroxyanthra[2,1,9-mna]naphth[2,3-h]acridin-5(16H)-one tetrakis(sulphate)

(a) in the presence of Pyridine , with Chlorosulfonic acid treatment ?C.I. Vat Black 25 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 25. The above two kinds of situation after alkaline, filter out insolubles, remove Pyridine and salting out.

brown light grey. Black powder. Soluble in water. Used for cotton fabric dyeing, generally used for direct dyeing and reserving dyeing, is not used for printing. In the acidic conditions to wool and silk dyed.

Standard	Ironing Fastness	Chlorine bleach	Light Fastness	Mercerized	Oxygen bleach	Soaping
						Fading	Stain
ISO	4	4	8	5	4	4-5	5
AATCC	5	4	7-8	5	4-5