March 20, 2023
I’m a rocket fuel that’s relatively safe to store.
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Image of 1,1-Dimethylhydrazine 3D Image of 1,1-Dimethylhydrazine

1,1-Dimethylhydrazine, frequently called unsymmetrical dimethylhydrazine (UDMH), is the third member of the hydrazine family to appear in Molecule of the Week. The first two were the parent molecule hydrazine in 2010 and methylhydrazine earlier this year. All these highly toxic hydrazines are used in rocket fuels.

Australian chemist Henry H. Hatt reported a synthesis of the hydrochloride salt1 of UDMH in the 1936 edition of Organic Syntheses. Hatt treated dimethylamine with nitric acid to produce the N-nitroso derivative, which was then reduced with zinc to form UDMH, isolated as the salt. Hatt later made UDMH by treating dimethylamine with chloramine; this is one of two current industrial production processes. In the other, acetylhydrazine is treated with formaldehyde and hydrogen to form a dimethyl derivative, which is then hydrolyzed to produce UDMH.

UDMH is a hypergolic rocket fuel, which means that it ignites when it is mixed with another component of the fuel. The second component is usually dinitrogen tetroxide. UDMH is generally preferred to hydrazine in rocket fuels because it autoignites at a higher temperature and is thus more stable in storage.

1. CAS Reg. No. 593-82-8.

1,1-Dimethylhydrazine hazard information*

Hazard class** GHS code and hazard statement
Flammable liquids, category 2 H225—Highly flammable liquid and vapor Chemical Safety Warning
Acute toxicity, oral, category 3 H301—Toxic if swallowed Chemical Safety Warning
Acute toxicity, dermal, category 3 H311—Toxic in contact with skin Chemical Safety Warning
Skin corrosion/irritation, category 1B H314—Causes severe skin burns and eye damage Chemical Safety Warning
Serious eye damage/eye irritation, category 1 H318—Causes serious eye damage Chemical Safety Warning
Acute toxicity, inhalation, category 2 H331—Fatal if inhaled Chemical Safety Warning
Germ cell mutagenicity, category 2 H340—Suspected of causing genetic defects Chemical Safety Warning
Carcinogenicity, category 1B H350—May cause cancer Chemical Safety Warning
Specific target organ toxicity, single exposure, category 1 H370—Causes damage to respiratory system, nervous system Chemical Safety Warning
Specific target organ toxicity, repeated exposure, category 1 H372—Causes damage through prolonged or repeated exposure to liver, blood system, respiratory system, nervous system Chemical Safety Warning
Short-term (acute) aquatic hazard, category 2 H401—Toxic to aquatic life Chemical Safety Warning
Long-term (chronic) aquatic hazard, category 2 H411—Toxic to aquatic life with long-lasting effects Chemical Safety Warning

*Compilation of two safety data sheets.
**Globally Harmonized System (GHS) of Classification and Labeling of Chemicals. Explanation of pictograms

Molecule of the Future

Darobactin A1 is a potential antibiotic that was discovered in 2019 by Kim Lewis at Northeastern University (Boston) and 14 collaborators there and at several other institutions in the United States and Germany. The authors isolated the molecule from species of Photorhabdus bacteria that live in the digestive systems of certain nematodes.

Molecule of the Future: Darobactin A

Lewis et al. found that darobactin A cured infections in laboratory animals caused by Gram-negative bacteria in the Enterobacteriaceae family, including Escherichia coli. In 2022, two total syntheses of darobactin A were reported: Niki R. Patel, David A. Petrone, David Sarlah, and collaborators at Merck (Rahway, NJ) and the University of Illinois at Urbana–Champaign performed the synthesis in 16 steps; Phil S. Baran at Scripps Research (La Jolla, CA) used 18 steps to accomplish the feat.

1. CAS Reg. No. 2409072-20-2.

Molecule of the Future

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fast facts

CAS Reg. No. 57-14-7
SciFinder nomenclature Hydrazine, 1,1-dimethyl-
Empirical formula C2H8N2
Molar mass 60.10 g/mol
Appearance Colorless liquid
Boiling point 64 °C
Water solubility Miscible
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