H2NNHCONHNH2

H2NNHCONHNH2, also known as semicarbazide hydrochloride when referring to its common salt form, is a chemical compound with the formula CH6N4O. It is derived from semicarbazide, a derivative of urea where one amino group is replaced by a hydrazine group. The parent compound, semicarbazide, is a white crystalline solid.

This compound is primarily utilized in organic chemistry as a derivatizing agent. It reacts with aldehydes and ketones to form semicarbazones, which are often crystalline solids with sharp melting points. This reaction is useful for the identification and characterization of carbonyl compounds. The formation of semicarbazones can also be used to isolate and purify aldehydes and ketones from mixtures.

Semicarbazide hydrochloride is soluble in water and ethanol. Its reactivity stems from the presence of both a carbonyl group and hydrazine moieties within its structure, allowing it to participate in condensation reactions with carbonyls. While semicarbazide itself can be a reagent, its hydrochloride salt is more commonly encountered due to its stability and ease of handling. The compound is typically prepared by reacting urea with hydrazine or its salts. It has also found some limited applications in analytical chemistry for the quantitative determination of carbonyl compounds.