Monomethylhydrazine

Monomethylhydrazine
Names
IUPAC name
Methylhydrazine[1]
Identifiers
60-34-4 YesY
635645
ChEMBL ChEMBL160520 YesY
ChemSpider 5837 YesY
EC Number 200-471-4
Jmol interactive 3D Image
MeSH Monomethylhydrazine
PubChem 6061
RTECS number MV5600000
UN number 1244
Properties
CH6N2
Molar mass 46.07 g·mol−1
Appearance Fuming, colourless liquid
Odor fishy, ammoniacal
Density 875 mg mL−1 (at 20 °C)
Melting point −52 °C (−62 °F; 221 K)
Boiling point 91 °C; 196 °F; 364 K
miscible[2]
log P −1.318
Vapor pressure 5.00 kPa (at 20 °C)
1.4325
Thermochemistry
134.93 J K−1 mol−1
165.94 J K−1 mol−1
54.14 kJ mol−1
−1305.8–−1304.6 kJ mol−1
Hazards
Safety data sheet inchem.org
GHS pictograms
GHS signal word DANGER
H225, H300, H311, H314, H330, H351, H411
P210, P260, P273, P280, P284
F+ T+ N
R-phrases R11, R24/25, R26, R34, R40, R51/53
S-phrases S16, S26, S36/37/39, S45, S60
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 4: Very short exposure could cause death or major residual injury. E.g., VX gas Reactivity code 4: Readily capable of detonation or explosive decomposition at normal temperatures and pressures. E.g., nitroglycerin Special hazards (white): no codeNFPA 704 four-colored diamond
4
4
4
Flash point −8 °C; 17 °F; 265 K [2]
196 °C (385 °F; 469 K)
Explosive limits 2.5–92%[2]
Lethal dose or concentration (LD, LC):
32 mg kg−1 (oral, rat)
34 ppm (rat, 4 hr)
74 ppm (rat, 4 hr)
162 ppm (monkey, 1 hr)
195 ppm (dog, 30 min)
145 ppm (monkey, 30 min)
272 ppm (mouse, 30 min)
427 ppm (rat, 30 min)
56 ppm (mouse, 4 hr)
143 ppm (hamster, 4 hr)[3]
US health exposure limits (NIOSH):
C 0.2 ppm (0.35 mg/m3) [skin][2]
Ca C 0.04 ppm (0.08 mg/m3) [2-hr][2]
Ca [20 ppm][2]
Related compounds
Related compounds
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY verify (what is YesYN ?)
Infobox references

Monomethylhydrazine (MMH) is a volatile hydrazine chemical with the chemical formula CH3 (NH)NH2. It is used as a rocket propellant in bipropellant rocket engines because it is hypergolic with various oxidizers such as nitrogen tetroxide (N2O4) and nitric acid (HNO3). As a propellant, it is described in specification MIL-PRF-27404.[4]

MMH is a hydrazine derivative that was once used in the orbital maneuvering system (OMS) and reaction control system (RCS) engines of NASA's Space Shuttle, which used MMH and MON-3 (a mixture of nitrogen tetroxide with approximately 3% nitric oxide). This chemical is toxic and carcinogenic in small amounts, but it is easily stored in outer space providing moderate performance for very low fuel tank system weight. Recently the European Space Agency (ESA) has attempted to seek new options in terms of bipropellant rocket combinations to avoid poisonous chemicals such as this and its relatives.[5]

MMH and its chemical relative unsymmetrical dimethylhydrazine (UDMH) have a key advantage that they are stable enough to be used in regeneratively cooled rocket engines. The Apollo Lunar Modules used a one-to-one mixture of hydrazine and UDMH (called Aerozine 50, or A-50) as one part of the rocket fuel for lunar landings and takeoff: the rocket motors formed a hypergolic mixture of the hydrazines with liquid dinitrogen tetroxide as the usual oxidizer. (Otherwise, red fuming nitric acid works.) About three tons of mixed hydrazines and four and one half tons of the oxidizer were required for each landing, and about one-third of those amounts for the lunar take-off to orbit.[6]

Monomethylhydrazine is believed to be the main cause of the toxicity of Gyromitra genus mushrooms, especially the false morel (Gyromitra esculenta). In these cases, MMH is formed by the hydrolysis of gyromitrin.[7]

Monomethylhydrazine is considered to be a possible occupational carcinogen,[8] and the occupational exposure limits to MMH are set at protective levels to account for the possible carcinogenicity.[9]

References

  1. ↑ "Monomethylhydrazine - Compound Summary". PubChem Compound. USA: National Center for Biotechnology Information. 26 March 2005. Identification and Related Records. Retrieved 2 May 2012.
  2. 1 2 3 4 5 6 "NIOSH Pocket Guide to Chemical Hazards #0419". National Institute for Occupational Safety and Health (NIOSH).
  3. ↑ "Methylhydrazine". Immediately Dangerous to Life and Health. National Institute for Occupational Safety and Health (NIOSH).
  4. ↑ MIL-PRF-27404 (1997-10-01). "Performance Specification, Propellant, Monomethylhydrazine". Retrieved 2011-05-21.
  5. ↑ International Conference on Green Propellant for Space Propulsion, European Space Agency
  6. ↑ Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. p. 492. ISBN 0-08-022057-6.
  7. ↑ Pyysalo H. (1975). "Some new toxic compounds in false morels, Gyromitra esculenta". Naturwissenschaften 62 (8): 395. doi:10.1007/BF00625355. PMID 1238907.
  8. ↑ Documentation for Immediately Dangerous To Life or Health Concentrations (IDLHs), Centers for Disease Control and Prevention
  9. ↑ NIOSH Pocket Guide to Chemical Hazards, Centers for Disease Control and Prevention
This article is issued from Wikipedia - version of the Tuesday, March 29, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.