Reddish brown powder. Water solubility is still good, aqueous solution is bluish red, add concentrated hydrochloric acid to produce date red precipitate, add concentrated alkali to orange-brown. Soluble in ethylene glycol ether, slightly soluble in ethanol, reddish orange, insoluble in other organic solvents. Orange to brown in concentrated sulfuric acid, produces dark blue-red precipitate after dilution; brown solution with precipitate in concentrated nitric acid. Insoluble in concentrated alkali; date red in concentrated ammonia.
[1] Sawada K, Ueda M. Adsorption behavior of direct dye on cotton in non-aqueous media[J]. Dyes and pigments, 2003, 58(1): 37-40.
