8,16-Pyranthrenediol, dibromo-, bis(hydrogen sulfate), disodium salt

Preparation

(a) in the presence of Pyridine , with Chlorosulfonic acid treatment C.I. Vat Orange 2 leuco ; (b) used in Pyridine metal (such as copper, iron, zinc, etc) and Sulfur trioxide source (such as Sulfur trioxide, Chlorosulfonic acid or Methyl chlorosulfonate) processing C.I. Vat Orange 2. The above two kinds of circumstances are through with alkali, filter out the insoluble,, remove Pyridine and salting-out.

Properties and Applications

red light orange. Purple powder. Soluble in 1, 2, 3, 4-Tetrahydronaphthalene and Xylene, slightly soluble in hot Chloroform, 2-Chlorophenol and Pyridine , insoluble in Etanol, Acetone and Toluene. Alkaline reduction for the red light purple leuco ; Acid reduction to orange color body hidden. In the dark for the strong sulfuric acid, to orange diluted. A light brittle. Mainly used for dyeing cotton roll and disseminated, good levelness, affinity is medium, can be directly printing, white performance is poor. Used for flax, viscose dyeing effect is good.