Unsymmetrical dimethylhydrazine
chemical compound
Unsymmetrical dimethylhydrazine (abbreviated as UDMH; also known as 1,1-dimethylhydrazine, heptyl or Geptil) is a chemical compound with the formula H2NN(CH3)2 that is primarily used as a rocket fuel. At room temperature, UDMH is a colorless liquid, with a sharp, fishy, ammonia-like smell typical of organic amines. Samples turn yellowish on exposure to air and absorb oxygen and carbon dioxide. It is miscible with water, ethanol, and kerosene. At concentrations between 2.5% and 95% in air, its vapors are flammable. It is not sensitive to shock.
Symmetrical dimethylhydrazine (1,2-dimethylhydrazine) also exists, but it is not as useful. UDMH can be oxidized in air to form many different substances, including toxic ones.
Synthesis
In 1875, UDMH was first prepared by Emil Fischer, who discovered and named the class of hydrazines, by reducing N-Nitrosodimethylamine with zinc in boiling acetic acid. Fischer's student Edward Renouf later studied UDMH more extensively as part of his doctoral dissertation.
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