Methyl nitrite

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Methyl nitrite
Trans-methyl-nitrite-2D-dimensions.svg
Trans-methyl-nitrite-3D-vdW.png
Names
Preferred IUPAC name
Methyl nitrite
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.009.882 OOjs UI icon edit-ltr-progressive.svg
PubChem CID
UNII
  • InChI=1S/CH3NO2/c1-4-2-3/h1H3 Yes check.svgY
    Key: BLLFVUPNHCTMSV-UHFFFAOYSA-N Yes check.svgY
  • InChI=1/CH3NO2/c1-4-2-3/h1H3
    Key: BLLFVUPNHCTMSV-UHFFFAOYAL
  • O=NOC
Properties
CH3NO2
Molar mass 61.040 g·mol−1
AppearanceYellow 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]
-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).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)

Methyl nitrite is an organic compound with the chemical formula CH
3ONO. It is a gas, and is the simplest alkyl nitrite.

Contents

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-3D-balls.png Trans-methyl-nitrite-3D-balls.png
cis-methyl nitritetrans-methyl nitrite

Synthesis

Methyl nitrite can be prepared by the reaction of silver nitrite with iodomethane: Silver nitrite (AgNO2) exists in solution as the silver ion, Ag+ and the nitrite ion, NO2−. One of the lone pairs on an oxygen from nitrite ion attacks the methyl group (—CH3), releasing the iodide ion into solution. [4] Unlike silver nitrite, silver iodide is highly insoluble in water and thus forms a solid. [5] Note that nitrogen is a better nucleophile than oxygen and most nitrites would react via an 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]

Preparation of methyl nitrite.png

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 nitrogen dioxide (itself formed by oxidation 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

Related Research Articles

In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula CH3. In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in many organic compounds. It is a very stable group in most molecules. While the methyl group is usually part of a larger molecule, bounded to the rest of the molecule by a single covalent bond, it can be found on its own in any of three forms: methanide anion, methylium cation or methyl radical. The anion has eight valence electrons, the radical seven and the cation six. All three forms are highly reactive and rarely observed.

<span class="mw-page-title-main">Nitric oxide</span> Colorless gas with the formula NO

Nitric oxide is a colorless gas with the formula NO. It is one of the principal oxides of nitrogen. Nitric oxide is a free radical: it has an unpaired electron, which is sometimes denoted by a dot in its chemical formula. Nitric oxide is also a heteronuclear diatomic molecule, a class of molecules whose study spawned early modern theories of chemical bonding.

<span class="mw-page-title-main">Nitrogen dioxide</span> Chemical compound with formula NO₂

Nitrogen dioxide is a chemical compound with the formula NO2. One of several nitrogen oxides, nitrogen dioxide is a reddish-brown gas. It is a paramagnetic, bent molecule with C2v point group symmetry. Industrially, NO2 is an intermediate in the synthesis of nitric acid, millions of tons of which are produced each year, primarily for the production of fertilizers.

Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula CH
3NO
2. It is the simplest organic nitro compound. It is a polar liquid commonly used as a solvent in a variety of industrial applications such as in extractions, as a reaction medium, and as a cleaning solvent. As an intermediate in organic synthesis, it is used widely in the manufacture of pesticides, explosives, fibers, and coatings. Nitromethane is used as a fuel additive in various motorsports and hobbies, e.g. Top Fuel drag racing and miniature internal combustion engines in radio control, control line and free flight model aircraft.

<span class="mw-page-title-main">Nitrous acid</span> Chemical compound

Nitrous acid is a weak and monoprotic acid known only in solution, in the gas phase, and in the form of nitrite salts. It was discovered by Carl Wilhelm Scheele, who called it "phlogisticated acid of niter". Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to give azo dyes.

The nitrite ion has the chemical formula NO−
2. Nitrite is widely used throughout chemical and pharmaceutical industries. The nitrite anion is a pervasive intermediate in the nitrogen cycle in nature. The name nitrite also refers to organic compounds having the –ONO group, which are esters of nitrous acid.

<span class="mw-page-title-main">Alkylation</span> Transfer of an alkyl group from one molecule to another

Alkylation is a chemical reaction that entails transfer of an alkyl group. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion, or a carbene. Alkylating agents are reagents for effecting alkylation. Alkyl groups can also be removed in a process known as dealkylation. Alkylating agents are often classified according to their nucleophilic or electrophilic character. In oil refining contexts, alkylation refers to a particular alkylation of isobutane with olefins. For upgrading of petroleum, alkylation produces a premium blending stock for gasoline. In medicine, alkylation of DNA is used in chemotherapy to damage the DNA of cancer cells. Alkylation is accomplished with the class of drugs called alkylating antineoplastic agents.

<span class="mw-page-title-main">Dinitrogen pentoxide</span> Chemical compound

Dinitrogen pentoxide is the chemical compound with the formula N2O5. It is one of the binary nitrogen oxides, a family of compounds that only contain nitrogen and oxygen. It exists as colourless crystals that sublime slightly above room temperature, yielding a colorless gas.

<span class="mw-page-title-main">Nitro compound</span> Organic compound containing an −NO₂ group

In organic chemistry, nitro compounds are organic compounds that contain one or more nitro functional groups. The nitro group is one of the most common explosophores used globally. The nitro group is also strongly electron-withdrawing. Because of this property, C−H bonds alpha (adjacent) to the nitro group can be acidic. For similar reasons, the presence of nitro groups in aromatic compounds retards electrophilic aromatic substitution but facilitates nucleophilic aromatic substitution. Nitro groups are rarely found in nature. They are almost invariably produced by nitration reactions starting with nitric acid.

<span class="mw-page-title-main">Hofmann elimination</span> Chemical reaction in organic chemistry

Hofmann elimination is an elimination reaction of an amine to form alkenes. The least stable alkene, called the Hofmann product, is formed. This tendency, known as the Hofmann alkene synthesis rule, is in contrast to usual elimination reactions, where Zaitsev's rule predicts the formation of the most stable alkene. It is named after its discoverer, August Wilhelm von Hofmann.

<span class="mw-page-title-main">Phosphorus triiodide</span> Chemical compound

Phosphorus triiodide (PI3) is an inorganic compound with the formula PI3. A red solid, it is too unstable to be stored for long periods of time; it is, nevertheless, commercially available. It is widely used in organic chemistry for converting alcohols to alkyl iodides. It is also a powerful reducing agent.

<span class="mw-page-title-main">Sodium iodide</span> Chemical compound

Sodium iodide (chemical formula NaI) is an ionic compound formed from the chemical reaction of sodium metal and iodine. Under standard conditions, it is a white, water-soluble solid comprising a 1:1 mix of sodium cations (Na+) and iodide anions (I−) in a crystal lattice. It is used mainly as a nutritional supplement and in organic chemistry. It is produced industrially as the salt formed when acidic iodides react with sodium hydroxide. It is a chaotropic salt.

The nitrosonium ion is NO+, in which the nitrogen atom is bonded to an oxygen atom with a bond order of 3, and the overall diatomic species bears a positive charge. It can be viewed as nitric oxide with one electron removed. This ion is usually obtained as the following salts: NOClO4, NOSO4H (nitrosylsulfuric acid, more descriptively written ONSO3OH) and NOBF4. The ClO−4 and BF−4 salts are slightly soluble in acetonitrile CH3CN. NOBF4 can be purified by sublimation at 200–250 °C and 0.01 mmHg (1.3 Pa).

<span class="mw-page-title-main">Alkyl nitrite</span> Organic compounds of the form R–O–N=O

In organic chemistry, alkyl nitrites are a group of organic compounds based upon the molecular structure R−O−N=O, where R represents an alkyl group. Formally they are alkyl esters of nitrous acid. They are distinct from nitro compounds.

The chemical element nitrogen is one of the most abundant elements in the universe and can form many compounds. It can take several oxidation states; but the most common oxidation states are -3 and +3. Nitrogen can form nitride and nitrate ions. It also forms a part of nitric acid and nitrate salts. Nitrogen compounds also have an important role in organic chemistry, as nitrogen is part of proteins, amino acids and adenosine triphosphate.

Lithium nitrite is the lithium salt of nitrous acid, with formula LiNO2. This compound is hygroscopic and very soluble in water. It is used as a corrosion inhibitor in mortar. It is also used in the production of explosives, due to its ability to nitrosate ketones under certain conditions.

<span class="mw-page-title-main">Hexanitroethane</span> Chemical compound

Hexanitroethane (HNE) is an organic compound with chemical formula C2N6O12 or (O2N)3C-C(NO2)3. It is a solid matter with a melting point of 135 °C.

In chemistry, hyponitrite may refer to the anion N
2O2−
2 ([ON=NO]2−), or to any ionic compound that contains it. In organic chemistry, it may also refer to the group −O−N=N−O−, or any organic compound with the generic formula R1−O−N=N−O−R2, where R1 and R2 are organic groups. Such compounds can be viewed as salts and esters of hyponitrous acid. An acid hyponitrite is an ionic compound with the anion HN
2O−
2 ([HON=NO]−).

<span class="mw-page-title-main">Sodium hyponitrite</span> Chemical compound

Sodium hyponitrite is a solid ionic compound with formula Na
2N
2O
2 or (Na+
)2[ON=NO]2−.

Nitroxylic acid or hydronitrous acid is an unstable reduced oxonitrogen acid. It has formula H4N2O4 containing nitrogen in the +2 oxidation state. The corresponding anion called nitroxylate is N
2O4−
4 or NO2−
2.

References

  1. 1 2 3 4 Haynes, p. 3.382
  2. ↑ Haynes, p. 5.20
  3. ↑ Van Der Veken, B. J.; Maas, R.; Guirgis, G. A.; Stidham, H. D.; Sheehan, T. G.; Durig, James R. (1990). "Infrared spectrum, ab initio calculations, barriers to internal rotation and structural parameters for methyl nitrite". Journal of Physical Chemistry . 94 (10): 4029–39. doi:10.1021/j100373a028.
  4. 1 2 Pavia, Donald L.; Lampman, Gary M.; Kriz, George S. (2004). Organic Chemistry. Vol. 2. Mason, Ohio: Thompson Custom Publishing. ISBN   978-0-03-014813-2. OCLC   236055357.
  5. ↑ Darrell D. Ebbing; Steven D. Gammon (2005). General Chemistry (8th ed.). Boston: Houghton Mifflin. ISBN   978-0-618-39941-3.
  6. 1 2 METHYL NITRITE – National Library of Medicine HSDB Database. Toxnet.nlm.nih.gov. Retrieved on 2019-03-10.
  7. ↑ Rodgman, Alan; Perfetti, Thomas A. (2016-04-19). The Chemical Components of Tobacco and Tobacco Smoke. CRC Press. ISBN   9781466515529.
  8. ↑ Summers-Smith, J. Denis (September 2007). "Is unleaded petrol a factor in urban House Sparrow decline?". British Birds. 100: 558. ISSN   0007-0335.
  9. ↑ Methyl Nitrite. Cameochemicals.noaa.gov. Retrieved on 2019-03-10.
  10. ↑ Bretherick, L. (2016-10-27). Bretherick's Handbook of Reactive Chemical Hazards. Elsevier. ISBN   9781483162508.

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