Methyl nitrite

Source: Wikipedia, the free encyclopedia.
Not to be confused with nitromethane or methyl nitrate.
Methyl nitrite
Names
Preferred IUPAC name
Methyl nitrite
Identifiers
3D model (
JSmol
)
ChemSpider
ECHA InfoCard
 100.009.882 Edit this at Wikidata
UNII
  • InChI=1S/CH3NO2/c1-4-2-3/h1H3 checkY
    Key: BLLFVUPNHCTMSV-UHFFFAOYSA-N checkY
  • InChI=1/CH3NO2/c1-4-2-3/h1H3
    Key: BLLFVUPNHCTMSV-UHFFFAOYAL
  • O=NOC
Properties
CH3NO2
Molar mass 61.040 g·mol−1
Appearance Yellow gas[1]
Density 0.991 g/cm3[1]
Melting point −16 °C (3 °F; 257 K)[1]
Boiling point −12 °C (10 °F; 261 K)[1]
Thermochemistry[2]
Std enthalpy of
formation
(ΔfH⦵298)
 -66.1 kJ/mol
Hazards
Safety data sheet (SDS) External MSDS
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Methyl nitrite is an

alkyl nitrite
.

Structure

At room temperature, methyl nitrite exists as a mixture of cis and trans conformers. The cis conformer is 3.13 kJ mol−1, more stable than the trans form, with an energy barrier to rotation of 45.3 kJ mol−1.[3] The cis and trans structure have also been determined by microwave spectroscopy (see external links).

cis-methyl nitrite trans-methyl nitrite

Synthesis

Methyl nitrite can be prepared by the reaction of

SN2-like mechanism and the major product would be nitromethane. For example, sodium and potassium nitrite reacting with iodomethane would produce mostly nitromethane, with methyl nitrite as the minor product. However, the presence of the silver ion in solution has a stabilizing effect on the formation of carbocation intermediates, increasing the percent yield of methyl nitrite. In either case, some nitromethane and methyl nitrite are both formed.[4]

The figure shows the two gas-phase structures of methyl nitrite, as determined by IR and microwave spectroscopy.

Methyl nitrite free of nitromethane can be made by reacting iodomethane with nitrogen dioxide:

Properties and uses

Methyl nitrite is a precursor and intermediate, e.g. during production of phenylpropanolamine.[6]

Methyl nitrite is also present in aged cigarette smoke. Here it is presumably formed from nitrous oxide (itself formed by autoxidation of nitric oxide) and methanol.[7]

Environmental impact

As one product of the combustion of

unleaded petrol in air, methyl nitrite has been proposed as a cause of the decline of insects, and hence that of songbirds in Europe.[8]

Safety

Methyl nitrite is a toxic asphyxiating gas, a potent cyanotic agent. Exposure may result in methemoglobinemia.[6]

Methyl nitrite is an oxidizing agent and a heat-sensitive explosive; its sensitivity increases in presence of metal oxides. With inorganic bases it forms explosive salts. It forms explosive mixtures with air. It is used as a rocket propellant, a monopropellant.[9] It explodes more violently than ethyl nitrite. Lower alkyl nitrites may decompose and burst the container even when stored under refrigeration.[10]

See also

References

  1. ^ a b c d Haynes, p. 3.382
  2. ^ Haynes, p. 5.20
  3. doi:10.1021/j100373a028
    .
  4. ^
    OCLC 236055357
    .
  5. ISBN 978-0-618-39941-3
    .
  6. ^ a b METHYL NITRITE – National Library of Medicine HSDB Database. Toxnet.nlm.nih.gov. Retrieved on 2019-03-10.
  7. ISBN 9781466515529
    .
  8. ISSN 0007-0335
    .
  9. ^ Methyl Nitrite. Cameochemicals.noaa.gov. Retrieved on 2019-03-10.
  10. ISBN 9781483162508
    .

Cited sources

External links

Wikimedia Commons has media related to Methyl nitrite.
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