Chemical Properties
It assumes a grey or violet shade in commercial products. It is insoluble in cold water, slightly soluble in boiling water, and very soluble in alcohol, ether, and chloroform. The aqueous solution turns red on contact with oxidizing agents, such as bromine, iron(III) chloride, or potassium permanganate. The dihydrochloride melts at 254 ℃ with decomposition.
