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
3
ONO
. 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 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

Related Research Articles

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

Amyl nitrite is a chemical compound with the formula C5H11ONO. A variety of isomers are known, but they all feature an amyl group attached to the nitrite functional group. The alkyl group is unreactive and the chemical and biological properties are mainly due to the nitrite group. Like other alkyl nitrites, amyl nitrite is bioactive in mammals, being a vasodilator, which is the basis of its use as a prescription medicine. As an inhalant, it also has a psychoactive effect, which has led to its recreational use, with its smell being described as that of old socks or dirty feet. It is also referred to as banapple gas.

<span class="mw-page-title-main">Ether</span> Organic compounds made of alkyl/aryl groups bound to oxygen (R–O–R)

In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula R−O−R′, where R and R′ represent the alkyl or aryl groups. Ethers can again be classified into two varieties: if the alkyl or aryl groups are the same on both sides of the oxygen atom, then it is a simple or symmetrical ether, whereas if they are different, the ethers are called mixed or unsymmetrical ethers. A typical example of the first group is the solvent and anaesthetic diethyl ether, commonly referred to simply as "ether". Ethers are common in organic chemistry and even more prevalent in biochemistry, as they are common linkages in carbohydrates and lignin.

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">Haloalkane</span> Group of chemical compounds derived from alkanes containing one or more halogens

The haloalkanes are alkanes containing one or more halogen substituents. They are a subset of the general class of halocarbons, although the distinction is not often made. Haloalkanes are widely used commercially. They are used as flame retardants, fire extinguishants, refrigerants, propellants, solvents, and pharmaceuticals. Subsequent to the widespread use in commerce, many halocarbons have also been shown to be serious pollutants and toxins. For example, the chlorofluorocarbons have been shown to lead to ozone depletion. Methyl bromide is a controversial fumigant. Only haloalkanes that contain chlorine, bromine, and iodine are a threat to the ozone layer, but fluorinated volatile haloalkanes in theory may have activity as greenhouse gases. Methyl iodide, a naturally occurring substance, however, does not have ozone-depleting properties and the United States Environmental Protection Agency has designated the compound a non-ozone layer depleter. For more information, see Halomethane. Haloalkane or alkyl halides are the compounds which have the general formula "RX" where R is an alkyl or substituted alkyl group and X is a halogen.

Nitromethane, sometimes shortened to simply "nitro", is an organic compound with the chemical formula CH
3
NO
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. Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to give azo dyes.

<span class="mw-page-title-main">Williamson ether synthesis</span> Method for preparing ethers

The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol (alkoxide). This reaction was developed by Alexander Williamson in 1850. Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an SN2 reaction. This reaction is important in the history of organic chemistry because it helped prove the structure of ethers.

<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 a common misconception that PI3 is too unstable to be stored; it is, in fact, commercially available. It is widely used in organic chemistry for converting alcohols to alkyl iodides. It is also a powerful reducing agent. Note that phosphorus also forms a lower iodide, P2I4, but the existence of PI5 is doubtful at room temperature.

Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound with the formula CH3I. It is a dense, colorless, volatile liquid. In terms of chemical structure, it is related to methane by replacement of one hydrogen atom by an atom of iodine. It is naturally emitted by rice plantations in small amounts. It is also produced in vast quantities estimated to be greater than 214,000 tons annually by algae and kelp in the world's temperate oceans, and in lesser amounts on land by terrestrial fungi and bacteria. It is used in organic synthesis as a source of methyl groups.

The Negishi coupling is a widely employed transition metal catalyzed cross-coupling reaction. The reaction couples organic halides or triflates with organozinc compounds, forming carbon-carbon bonds (C-C) in the process. A palladium (0) species is generally utilized as the metal catalyst, though nickel is sometimes used. A variety of nickel catalysts in either Ni0 or NiII oxidation state can be employed in Negishi cross couplings such as Ni(PPh3)4, Ni(acac)2, Ni(COD)2 etc.

<span class="mw-page-title-main">Organocopper chemistry</span> Compound with carbon to copper bonds

Organocopper chemistry is the study of the physical properties, reactions, and synthesis of organocopper compounds, which are organometallic compounds containing a carbon to copper chemical bond. They are reagents in organic chemistry.

<i>trans</i>-Cyclooctene Chemical compound

trans-Cyclooctene is a cyclic hydrocarbon with the formula [–(CH2)6CH=CH–], where the two C–C single bonds adjacent to the double bond are on opposite sides of the latter's plane. It is a colorless liquid with a disagreeable odor.

Organoiodine chemistry is the study of the synthesis and properties of organoiodine compounds, or organoiodides, organic compounds that contain one or more carbon–iodine bonds. They occur widely in organic chemistry, but are relatively rare in nature. The thyroxine hormones are organoiodine compounds that are required for health and the reason for government-mandated iodization of salt.

<span class="mw-page-title-main">Cyclopentadienyliron dicarbonyl dimer</span> Chemical compound

Cyclopentadienyliron dicarbonyl dimer is an organometallic compound with the formula [(η5-C5H5)Fe(CO)2]2, often abbreviated to Cp2Fe2(CO)4, [CpFe(CO)2]2 or even Fp2, with the colloquial name "fip dimer". It is a dark reddish-purple crystalline solid, which is readily soluble in moderately polar organic solvents such as chloroform and pyridine, but less soluble in carbon tetrachloride and carbon disulfide. Cp2Fe2(CO)4 is insoluble in but stable toward water. Cp2Fe2(CO)4 is reasonably stable to storage under air and serves as a convenient starting material for accessing other Fp (CpFe(CO)2) derivatives (described below).

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

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

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

Sulfoxylic acid (H2SO2) (also known as hyposulfurous acid or sulfur dihydroxide) is an unstable oxoacid of sulfur in an intermediate oxidation state between hydrogen sulfide and dithionous acid. It consists of two hydroxy groups attached to a sulfur atom. Sulfoxylic acid contains sulfur in an oxidation state of +2. Sulfur monoxide (SO) can be considered as a theoretical anhydride for sulfoxylic acid, but it is not actually known to react with water.

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
2
O4−
4
or NO2−
2
.

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

Trimethylplatinum iodide is the organoplatinum complex with the formula [(CH3)3PtI]4. It is a white, air-stable solid that was one of the first σ-alkyl metal complexes reported. It arises from the reaction of potassium hexachloroplatinate with methylmagnesium iodide. The complex exists as a tetramer: a cubane-type cluster with four octahedral Pt(IV) centers linked by four iodides as triply bridging ligands. Due to its stability, it is often utilized as a precursor en route to the synthesis of other organoplatinum compound, such as hydrosilylation catalysts. It is also used as a precursor for forming platinum layers for electronics.

References

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  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. 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. ISBN   9781483162508.

Cited sources