Methylamine
| Methylamine | |
|---|---|
 |
|
 |
 |
|
aminomethane, methanamine |
|
|
Other names
|
|
| Identifiers | |
| Abbreviations | MMA |
| CAS number | 74-89-5  |
| PubChem | 6329 |
| ChemSpider | 6089 |
| EC number | 200-820-0 |
| UN number | 1061 |
| DrugBank | DB01828 |
| KEGG | C00218 |
| MeSH | methylamine |
| ChEBI | CHEBI:16830  |
| ChEMBL | CHEMBL43280 |
| RTECS number | PF6300000 |
| Beilstein Reference | 741851 |
| Gmelin Reference | 145 |
| 3DMet | B00060 |
| Jmol-3D images | Image 1 |
|
|
|
|
| Properties | |
| Molecular formula | CH5N |
| Molar mass | 31.06 g mol−1 |
| Appearance | Colorless gas |
| Odor | Fishy, ammoniacal |
| Melting point |
-93 °C, 180.05 K, -136 °F |
| Boiling point |
-7--6 °C, 266.5-267.1 K, 20-21 °F |
| Solubility in water | 1.08 kg L−1 (at 20 °C) |
| log P | −0.472 |
| Vapor pressure | 186.10 kPa (at 20 °C) |
| kH | 1.4 mmol Pa−1 kg−1 |
| Basicity (pKb) | 3.36 |
| Viscosity | 230 μPa s (at 0 °C) |
| Dipole moment | 1.31 D |
| Thermochemistry | |
| Std enthalpy of formation ΔfH |
−23.5 kJ mol−1 |
| Hazards | |
| MSDS | emdchemicals.com |
| GHS pictograms |    |
| GHS signal word | DANGER |
| GHS hazard statements | H220, H315, H318, H332, H335 |
| GHS precautionary statements | P210, P261, P280, P305+351+338, P410+403 |
| EU Index | 612-001-00-9 |
| EU classification |  F+  Xn |
| R-phrases | R12, R20, R37/38, R41 |
| S-phrases | (S2), S16, S26, S39 |
| NFPA 704 |
 4
3
0
|
| Flash point | <−30 °C |
| Autoignition temperature |
430 °C |
| Explosive limits | 4.9–20.8% |
| LD50 | 100 mg kg−1 (oral, rat) |
| Related compounds | |
| Related alkanamines | ethylamine, dimethylamine, trimethylamine |
| Related compounds | ammonia |
 (verify) (what is:  / ?)Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) |
|
| Infobox references | |
Methylamine is the organic compound with a formula of CH3NH2. This colourless gas is a derivative of ammonia, but with one H atom replaced by a methyl group. It is the simplest primary amine. It is sold as a solution in methanol, ethanol, THF, and 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. Over 1 million tonnes are produced annually.[1]
Contents |
Production [edit]
Methylamine is prepared commercially by the reaction of ammonia with methanol in the presence of a silicoaluminate catalyst. Dimethylamine and trimethylamine are coproduced; the reaction kinetics and reactant ratios determine the ratio of the three products. The product most favoured by the reaction kinetics is trimethylamine.[2]
- CH3OH + NH3 → CH3NH2 + H2O
In this way, more than 400M kg are produced annually.
In the laboratory, methylamine hydrochloride is readily prepared by treating formaldehyde with ammonium chloride.[3]
- NH4Cl + H2CO → [CH2=NH2]Cl + H2O
- [CH2=NH2]Cl + H2CO + H2O → [CH3NH3]Cl + HCOOH
The colourless hydrochloride salt can be converted to the amine by the addition of strong base, like NaOH:
- [CH3NH3]Cl + NaOH → CH3NH2 + NaCl + H2O
Methylamine was first prepared by Wurtz by the hydrolysis of methyl isocyanate and related compounds.[4]
Reactivity and applications [edit]
Methylamine is a good nucleophile as it is highly basic and unhindered, although, 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 for liquid ammonia.[5]
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.[4]
Biological chemistry [edit]
Methylamine arises as a result of putrefaction and is a substrate for methanogenesis.[6]
Safety [edit]
The LD50 (mouse, s.c.) is 2.5 g/kg.[7]
Methylamine is also controlled as a List 1 precursor chemical by the United States Drug Enforcement Administration due to its use in the production of methamphetamine.
References [edit]
- ^ S.N. Bizzari (November 2008). "CEH Marketing Research Report: ALKYLAMINES (C1-C6)". Chemical Economics Handbook. SRI consulting. Retrieved July 2011.
- ^ Corbin D.R.; Schwarz S.; Sonnichsen G.C. (1997). "Methylamines synthesis: A review". Catalysis Today 37 (2): 71–102. doi:10.1016/S0920-5861(97)00003-5.
- ^ Marvel, C. S.; Jenkins, R. L. (1941), "Methylamine Hydrochloride", Org. Synth.; Coll. Vol. 1: 347
- ^ a b Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005. doi:10.1002/14356007.a02_001
- ^ M. G. DeBacker, El B. Mkadmi, F. X. Sauvage, J.-P. Lelieur, M. J. Wagner, R. Concepcion. J. Kim, L. E. H. McMills, J. L. Dye "The Lithium−Sodium−Methylamine System: Does a Low-Melting Sodide Become a Liquid Metal?" J. Am. Chem. Soc., 1996, vol. 118, pp 1997–2003. doi:10.1021/ja952634p
- ^ Thauer, R. K., "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson", Microbiology, 1998, 144, 2377-2406.
- ^ The Merck Index, 10th Ed. (1983), p.864, Rahway: Merck & Co.
