2,7-Naphthalenedisulfonicacid, 3-hydroxy-4-[2-(3-nitrophenyl)diazenyl]-, sodium salt (1:2)

M-nitroaniline diazo, coupled with 3-Hydroxynaphthalene-2,7-disulfonic acid.

orange. Red orange powder. Soluble in water and ethanol, in 90 ℃ water solubility of 50 g/L, also can dissolve in acetone. The strong sulfuric acid dyes for product red, dilute to orange. The water solution is orange, and strong hydrochloric acid to red light orange; Add thick sodium hydroxide solution for orange still.