Phenylhydrazine

Phenylhydrazine is the chemical compound with the formula C6H5NHNH2. Organic chemists abbreviate the compound PhNHNH2.

Chemical properties
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.

History
Phenylhydrazine was the first hydrazine derivative characterized, reported by Emil Fischer in 1875. He prepared it by reduction of a phenyl diazonium salt using sulfite salts. Fischer used phenylhydrazine to characterize sugars via formation of hydrazones with the sugar aldehyde. He also demonstrated in this first paper many of the key properties recognized for hydrazines.

Uses
Phenylhydrazine is used in preparation of indoles which are intermediates in the synthesis of various dyes and pharmaceuticals.

The compound is also used to induce acute hemolytic anemia in studies examining the hematopoietic system.

Safety
Exposure to phenylhydrazine may cause contact dermatitis, hemolytic anemia, and liver and kidney injury.