disodium 1,5-dibenzamidoanthracene-9,10-diyl bis(sulphate)

(a) in the presence of Pyridine, with Chlorosulfonic acid treatment C.I. Vat Yellow 3?leuco; (b) used in Pyridine?metal (such as copper, iron, zinc, etc) and Sulfur trioxide source (such as Sulfur trioxide, chlorosulfonic or Methyl chlorosulfonate) processing ?C.I. Vat Yellow 3. The above two kinds of circumstances are through with alkali, filter out the insoluble,, remove Pyridine and salting-out.

yellow.

Standard	Ironing Fastness	Chlorine bleach	Light Fastness	Mercerized	Oxygen bleach	Soaping
						Fading	Stain
ISO	5	5	6	4-5	5	5	5
AATCC	5	5	5	4	4