Phenylhydrazine (PHZ)

Phenylhydrazine is the chemical compound with the formula C6H5NHNH2. Phenylhydrazine forms monoclinic prisms that melt to an oil around room temperature which may turn yellow to dark red upon exposure to air. Phenylhydrazine is miscible with ethanol, diethyl ether, chloroform, and benzene. It is sparingly soluble in water. Phenylhydrazine is prepared by reducing aniline with sodium nitrite in the presence of hydrogen chloride to form the diazonium salt, which is subsequently reduced using sodium sulfite in the presence of sodium hydroxide to form the final product. Phenylhydrazine is used to prepare indoles via the Fischer Indole Synthesis, which are intermediates in the synthesis of various dyes and pharmaceuticals. Phenylhydrazine is used to form phenylhydrazones of natural mixtures of simple sugars in order to render the differing sugars easily separable from each other.