Unsymmetrical dimethylhydrazine, also known as 1,1-dimethylhydrazine, 1,1-dimethylhydrazine, is an organic compound, chemical formula CtwoHeightNtwo, colorless liquid, highly toxic.UDMH is the main fuel for launch test and carrier rocket of missile, satellite, airship, etc.
On October 27, 2017, the list of carcinogens published by the International Agency for Research on Cancer of the World Health Organization (WHO) was preliminarily collated for reference, and 1,1-dimethylhydrazine was included in the list of Category 2B carcinogens.[2]
In February 1968, UDMH, a high-performance chemical propellant developed under the leadership of Li Junxian, was born, and its production process and product quality reached the world's advanced level.Li Zhiqiang, President of Liming Research Institute of Chemical Industry: Academician Li decided to use the gas-phase ammonia chloride method to make UDMH at the risk of safety and responsibility, but although the gas phase UDMH has a high speed, it is relatively toxic. Academician Li and the research team used the liquid phase method to develop the production of UDMH, which took half a year to develop successfully.
For decades of wind and rain, Li Junxian's quest for space dreams has never stopped. Until now, the propellants he developed are still used in the Shenzhou V and Shenzhou VI manned spacecraft.He often said, "No carelessness and hypocrisy are allowed in scientific research." His style and spirit have infected generations of people in Liming Academy.
Physical and chemical properties
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Density: 0.793g/cmthree
Melting point: - 58 ℃
Boiling point: 63.9 ℃
Flash point: - 15 ℃ (CC)
Saturated vapor pressure: 16.4kPa (20 ℃)
Critical temperature: 250 ℃
Critical pressure: 5.42MPa
Ignition temperature: 249 ℃
Upper explosive limit（V/V）：95％
Lower explosive limit（V/V）：2.0％
Appearance: colorless liquid
Solubility: miscible with water, miscible with dimethylformamide, ethanol, ether and hydrocarbon[1]
Molecular structure data
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Molar refractive index: 18.57
Molar volume (cmthree/mol）：72.4
Isotonic specific volume (90.2K): 166.4
Surface tension (dyne/cm): 27.8
Polarization (10-24cmthree）：7.36[1]
Calculate chemical data
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Reference value of drainage parameter calculation (XlogP): - 0.5
Number of hydrogen bond donors: 1
Number of hydrogen bond receptors: 2
Number of rotatable chemical bonds: 0
Number of tautomers: 0
Topological molecular polar surface area: 29.3
Number of heavy atoms: 4
Surface charge: 0
Complexity: 11.5
Number of isotope atoms: 0
Determine the number of atomic structure centers: 0
Number of uncertain atomic structure centers: 0
Determine the number of chemical bond structure centers: 0
Number of uncertain chemical bond structure centers: 0
Number of covalent bond units: 1[1]
toxicology data
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1. Acute toxicity
LDfifty: 122mg/kg (rat by mouth);1060mg/kg (rabbit percutaneous)
LCfifty: 252ppm (inhaled by rats, 4h)
2. Subacute and chronic toxicity
Dog Inhalation 12.5mg/mthree, 6 hours a day, 5 times a week, 26 weeks, weight loss, sleepiness, mild anemia.
UDMH is a high specific impulse liquid rocket fuel, which has the advantage of high specific impulse value and can automatically ignite when contacting with oxidant:
UDMH is one of the propellants of the "Long March 2F" carrier rocket engine, and the conventional oxidant is nitrogen tetroxide:
security information
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Safety terminology
S45：In case of accident or if you feel unwell, seek medical advice immediately (show the lable where possible).
In case of an accident or feeling unwell, seek medical advice immediately (show the label if possible).
S53：Avoid exposure - obtain special instructions before use.
Avoid contact and obtain special instructions before use.
S61：Avoid release to the environment. Refer to special instructions/Safety data sheets.
To avoid release into the environment, refer to special instructions/safety receipt instructions.
Risk terminology
R11：Highly flammable.
Highly flammable.
R23/25：Toxic by inhalation and if swallowed.
Toxic by inhalation and if swallowed.
R34：Causes burns.
Causes burns.
R45：May cause cancer.
May cause cancer.
R51/53：Toxic to aquatic organisms, may cause long-term adverse effects in the aquatic environment.
It is toxic to aquatic organisms and may cause long-term adverse effects in the aquatic environment.
