Diazomethane
Chemical name	Diazomethane
Chemical formula	CH2N2
Molecular mass	42.04 g/mol
Melting point	-145 °C
Boiling point	-23 °C
Density	1.4 (air=1)
CAS number	[334-88-3]
SMILES	C=[N+]=[N-]
Structure
Molecular shape	linear C=N=N
Dipole moment	polar
Hazards
MSDS	External MSDS
Main hazards	toxic and explosive
NFPA 704
Flash point	? °C
R/S statement for tmsCHN2	R: 12-19-22-66-67 S: 9-16-29-33
RTECS number	?
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour gas
Spectral data	UV, IR, NMR, MS
Related compounds
Related functional groups	R-N=N=N azide), R-N=N-R (azo)
Related compounds	R2CN2 R = Ph, tms, CF3
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Diazomethane is the chemical compound CH₂N₂. In the pure form at room temperature, it is a yellow gas, but it is almost universally used as a solution in diethyl ether. It is one of the more common diazo compounds. It is also toxic and potentially explosive. Image File history File links Diazomethane. ... Image File history File links Download high resolution version (843x531, 48 KB) Summary 3D representation of diazomethane created with ChemDraw. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... A chemical formula (also called molecular formula) is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... The molecular mass (abbreviated MM) of a substance, called molecular weight and abbreviated as MW, is the mass of one molecule of that substance, relative to the unified atomic mass unit u (equal to 1/12 the mass of one atom of carbon-12). ... 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A material safety data sheet or MSDS is a form containing data regarding the properties of a particular substance. ... Worker safety and health is the prevention and reduction of the number of occupational safety and health hazards at the places of employment, providing safe and healthful working conditions. ... NFPA 704 is a standard maintained by the U.S. National Fire Protection Association. ... The flash point of a flammable liquid is the lowest temperature at which it can form an ignitable mixture with air. ... Risk and Safety Statements, also known as R/S statements, R/S numbers, R/S phrases, and R/S sentences, is a system of hazard codes and phrases for labeling dangerous chemicals and compounds. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The refractive index (or index of refraction) of a material is the factor by which the phase velocity of electromagnetic radiation is slowed in that material, relative to its velocity in a vacuum. ... The dielectric constant εr (represented as or K in some cases) is defined as the ratio: where εs is the static permittivity of the material in question, and ε0 is the vacuum permittivity. ... Ultraviolet-Visible Spectroscopy or Ultraviolet-Visible Spectrophotometry (UV/ VIS) involves the spectroscopy of photons (spectrophotometry). ... IR spectrum of a thin film of liquid ethanol. ... Nuclear Magnetic Resonance Spectroscopy most commonly known as NMR Spectroscopy is the name given to the technique which exploits the magnetic properties of nuclei. ... Basic schematic of mass spectrometry Mass spectrometry is an analytical technique used to measure the mass-to-charge ratio of ions. ... In organic chemistry functional groups are specific groups of atoms within molecules, that are responsible for the characteristic chemical reactions of those molecules. ... An azide is a N3- anion, or a reactive group in organic chemistry where a carbon substituent is attached as RN3. ... In chemistry, the standard state of a material is its state at 1 bar (100 kilopascals) and 25 degrees Celsius (298. ... Yellow is any color of light that stimulates both the red and green cone cells of the retina, but not the blue cone cells. ... A gas is one of the four main phases of matter (after solid and liquid, and followed by plasma), that subsequently appear as a solid material is subjected to increasingly higher temperatures. ... Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a characteristic smell. ... Diazo refers to a type of organic compound that has the general forumula R2C=N2. ... This article is concerned solely with chemical explosives. ...

Preparation^[1]

CH₂N₂ is usually prepared as a solution in diethylether and used in for converting carboxylic acids into their methyl esters or into their homologues. Diazomethane is prepared in the laboratory at mmol scale from precursors such as Diazald or N-methyl-N-nitroso-p-toluenesulfonamide and MNNG or 1-methyl-3-nitro-1-nitrosoguanidine. Diazald in a solution of diglyme and diethyl ether reacts with a warm aqueous solution of potassium hydroxide and the generated CH₂N₂ is collected by distillation. Diazomethane is liberated from a solution of MNNG in diethyl ether by addition of aqueous sodium hydroxide at low temperatures. Dissolving table salt in water In chemistry, a solution is a homogeneous mixture composed of one or more substances, known as solutes, dissolved in another substance, known as a solvent. ... Ether is the general name for a class of chemical compounds which contain an ether group — an oxygen atom connected to two (substituted) alkyl groups. ... Structure of a carboxylic acid The 3D structure of the carboxyl group A space-filling model of the carboxyl group Carboxylic acids are organic acids characterized by the presence of a carboxyl group, which has the SMILES formula -C(=O)-OH, usually written as -COOH. In general, the salts and... In chemistry a methyl-group is a hydrophobic Alkyl functional group which is derived from methane (CH4). ... General formula of a carboxylate ester. ... In chemistry, a homologous series is a series of organic compounds with a similar general formula, possessing similar chemical properties due to the presence of the same functional group, and shows a gradation in physical properties as a result of increase in molecular size and mass (see relative molecular mass). ... The mole (symbol: mol) is one of the seven SI base units and is commonly used in chemistry. ... Guanidine is a crystalline compound of strong alkalinity formed by the oxidation of guanine. ... Diglyme, or bis(2-methoxyethyl) ether, is a high boiling solvent. ... Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a characteristic smell. ... The chemical compound potassium hydroxide, (KOH) sometimes known as caustic potash, potassa, potash lye, and potassium hydrate, is a metallic base. ... Strathisla whisky distillery in Keith, Scotland Distillation is a method of separation of substances based on differences in their vapor pressures. ... Diethyl ether, also known as ether and ethoxyethane, is a clear, colorless, and highly flammable liquid with a low boiling point and a characteristic smell. ... Sodium hydroxide (NaOH), also known as lye or caustic soda, is a caustic metallic base. ... Image File history File links Diazomethane_precursors. ...

CH₂N₂ reacts with basic solutions of ²H₂O to give the deuterated derivative C²H₂N₂.^[2]

Assay

The concentration of CH₂N₂ can be determined in either of two convenient ways. It can be treated with an excess of benzoic acid in cold Et₂O. Unreacted benzoic acid is then assayed using titration with standard NaOH. Alternatively, the concentration of CH₂N₂ in Et₂O can be determined spectrophotometrically at 410 nm where its extinction coefficient, ε, is 7.2.

Other diazomethane compounds

Many substituted derivatives of diazomethane have been prepared:

• The very stable (CF₃)₂CN₂ (b.p. 12–13 °C),^[3]
• Ph₂CN₂ (m.p. 29–30 °C).^[4]
• (CH₃)₃SiCHN₂, which is commercially available as a solution and is as effective as CH₂N₂ for methylation.^[5]
• PhC(H)N₂, a red liquid b.p. < 25 °C at 0.1 mm Hg.^[6]

Safety

Diazomethane is toxic by inhalation or by contact with the skin or eyes (TLV 0.2ppm). Symptoms include chest discomfort, headache, weakness and, in severe cases, collapse.^[7] CH₂N₂ may explode when in contact with ground-glass joints or when heated to about 100 °C. Consequently specialized, scratch-free glassware and a blast shield should be employed for its use.

References

1. ^ J. A. Moore; D. E. Reed “Diazomethane” Organic Syntheses Collective Volume 5, page 351
2. ^ P. G. Gassman and W. J. Greenlee “Dideuterodiazomethane” Organic Syntheses Collective Volume 6, page 432.
3. ^ W. J. Middleton; D. M. Gale “Bis(Trifluoromethyl))diazomethane” Organic Syntheses Collective Volume 6, page 161
4. ^ L. I. Smith, K. L. Howard “Diphenyldiazomethane” Organic Syntheses Collective Volume 3, page 351
5. ^ T. Shioiri, T. Aoyama, S. Mori “Trimethylsilyldiazomethane” Organic Syntheses Collected Volume, Volume 8, page 612.
6. ^ X. Creary “Tosylhydrazone Salt Pyrolyses: Phenydiazomethanes” Organic Syntheses, Coll. Vol. 7, p.438 (1990); Vol. 64, p.207 (1986).
7. ^ Muir, GD (ed.) 1971, Hazards in the Chemical Laboratory, The Royal Institute of Chemistry, London.

External links

• MSDS diazomethane
• Sigmaaldrich technical bulletin

• For a full list of external links to MSDSs, spectroscopic data, commercial suppliers etc. for this compound, see Wikipedia:Chemical sources.