Methylamine is an organic compound with a formula of CH3NH2. This colorless gas is a derivative of ammonia, but with one hydrogen atom being replaced by a methyl group. It is the simplest primary amine. It is sold as a solution in methanol, ethanol, tetrahydrofuran, or water, or as the anhydrous gas in pressurized metal containers. Industrially, methylamine is transported in its anhydrous form in pressurized railcars and tank trailers. It has a strong odor similar to fish. Methylamine is used as a building block for the synthesis of many other commercially available compounds.
|Preferred IUPAC name|
3D model (JSmol)
CompTox Dashboard (EPA)
|Molar mass||31.058 g·mol−1|
|Density||656.2 kg m−3 (at 25 °C)|
|Melting point||−93.10 °C; −135.58 °F; 180.05 K|
|Boiling point||−6.6 to −6.0 °C; 20.0 to 21.1 °F; 266.5 to 267.1 K|
|1080 g.L−1 (at 20 °C)|
|Vapor pressure||186.10 kPa (at 20 °C)|
|1.4 mmol Pa−1 kg−1|
|Viscosity||230 μPa s (at 0 °C)|
Std enthalpy of
|−23.5 kJ mol−1|
|Safety data sheet||emdchemicals.com|
|GHS Signal word||Danger|
|H220, H315, H318, H332, H335|
|P210, P261, P280, P305+351+338, P410+403|
|NFPA 704 (fire diamond)|
|Flash point||−10 °C; 14 °F; 263 K (liquid, gas is extremely flammable)|
|430 °C (806 °F; 703 K)|
|Lethal dose or concentration (LD, LC):|
LD50 (median dose)
|100 mg kg−1 (oral, rat)|
LC50 (median concentration)
|1860 ppm (mouse, 2 hr)|
|NIOSH (US health exposure limits):|
|TWA 10 ppm (12 mg/m3)|
|TWA 10 ppm (12 mg/m3)|
IDLH (Immediate danger)
|ethylamine, dimethylamine, trimethylamine|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Methylamine is prepared commercially by the reaction of ammonia with methanol in the presence of an aluminosilicate catalyst. Dimethylamine and trimethylamine are co-produced; the reaction kinetics and reactant ratios determine the ratio of the three products. The product most favored by the reaction kinetics is trimethylamine.
- CH3OH + NH3 → CH3NH2 + H2O
Methylamine was first prepared in 1849 by Charles-Adolphe Wurtz via the hydrolysis of methyl isocyanate and related compounds. An example of this process includes the use of the Hofmann rearrangement, to yield methylamine from acetamide and bromine gas.
- NH4Cl + H2CO → [CH2=NH2]Cl + H2O
- [CH2=NH2]Cl + H2CO + H2O → [CH3NH3]Cl + HCO2H
The colorless hydrochloride salt can be converted to an amine by the addition of a strong base, such as sodium hydroxide (NaOH):
- [CH3NH3]Cl + NaOH → CH3NH2 + NaCl + H2O
Another method of methylamine production is spontaneous decarboxylation of glycine with a strong base in water.
Reactivity and applications
Methylamine is a good nucleophile as it is an unhindered amine. As an amine it is considered a weak base. Its use in organic chemistry is pervasive. Some reactions involving simple reagents include: with phosgene to methyl isocyanate, with carbon disulfide and sodium hydroxide to the sodium methyldithiocarbamate, with chloroform and base to methyl isocyanide and with ethylene oxide to methylethanolamines. Liquid methylamine has solvent properties analogous to those of liquid ammonia.
Representative commercially significant chemicals produced from methylamine include the pharmaceuticals ephedrine and theophylline, the pesticides carbofuran, carbaryl, and metham sodium, and the solvents N-methylformamide and N-methylpyrrolidone. The preparation of some surfactants and photographic developers require methylamine as a building block.
The Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) have set occupational exposure limits at 10 ppm or 12 mg/m3 over an eight-hour time-weighted average.
In popular culture
In the TV series Breaking Bad, Walter White manufactures methamphetamine through the reductive amination of phenylacetone with methylamine. The methylamine was stolen from a warehouse in the season one episode "A No-Rough-Stuff-Type Deal" and from a moving train in the season five episode "Dead Freight."
- Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 670. doi:10.1039/9781849733069-00648. ISBN 978-0-85404-182-4.
- NIOSH Pocket Guide to Chemical Hazards. "#0398". National Institute for Occupational Safety and Health (NIOSH).
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- Charles-Adolphe Wurtz (1849) "Sur une série d'alcalis organiques homologues avec l'ammoniaque" (On a series of homologous organic alkalis containing ammonia), Comptes rendus … , 28 : 223-226. Note: Wurtz's empirical formula for methylamine is incorrect because chemists in that era used an incorrect atomic mass for carbon (6 instead of 12).
- Mann, F. G.; Saunders, B. C. (1960). Practical Organic Chemistry, 4th Ed. London: Longman. p. 128. ISBN 9780582444072.
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- Peter Scott (ed.). Linker Strategies in Solid-Phase Organic Synthesis. p. 80.
...an unhindered amine such as methylamine
- Debacker, Marc G.; Mkadmi, El Bachir; Sauvage, François X.; Lelieur, Jean-Pierre; Wagner, Michael J.; Concepcion, Rosario; Kim, Jineun; McMills, Lauren E. H.; Dye, James L. (1996). "The Lithium−Sodium−Methylamine System: Does a Low-Melting Sodide Become a Liquid Metal?". Journal of the American Chemical Society. 118 (8): 1997. doi:10.1021/ja952634p.
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- CDC - NIOSH Pocket Guide to Chemical Hazards
- Title 21 Code of Federal Regulations
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