Methylamine

Methylamine

Ball and stick model of methylamine
Names
IUPAC name aminomethane, methanamine
Other names monomethylamine MMA glycamine
Identifiers
CAS Number	74-89-5 Y
3DMet	B00060
Abbreviations	MMA
Beilstein Reference	741851
ChEBI	CHEBI:16830 N
ChEMBL	ChEMBL43280 Y
ChemSpider	6089 Y
DrugBank	DB01828 N
EC Number	200-820-0
Gmelin Reference	145
Jmol 3D model	Interactive image
KEGG	C00218 Y
MeSH	methylamine
PubChem	6329
RTECS number	PF6300000
UN number	1061
InChI InChI=1S/CH5N/c1-2/h2H2,1H3 Y Key: BAVYZALUXZFZLV-UHFFFAOYSA-N Y
SMILES CN
Properties
Chemical formula	CH5N
Molar mass	31.06 g·mol−1
Appearance	Colorless gas
Odor	Fishy, ammoniacal
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
Solubility in water	1.08 kg L−1 (at 20 °C)
log P	−0.472
Vapor pressure	186.10 kPa (at 20 °C)
Henry's law constant (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 (ΔfHo298)	−23.5 kJ mol−1
Vapor pressure	{{{value}}}
Related compounds
Related alkanamines	ethylamine, dimethylamine, trimethylamine
Related compounds	ammonia
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Methylamine is an organic compound with a formula of CH₃NH₂. This colorless 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.

Industrial production

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.

CH₃OH + NH₃ → CH₃NH₂ + H₂O

In this way, an estimated 115,000 tons were produced In 2005.

Laboratory methods

Methylamine was first prepared in 1849 by Wurtz by the hydrolysis of methyl isocyanate and related compounds. An example of this process includes the use of Hofmann rearrangement to yield methylamine from acetamide and bromine gas.

In the laboratory methylamine hydrochloride is readily prepared by various other methods. One method entails treating formaldehyde with ammonium chloride.

NH₄Cl + H₂CO → [CH₂=NH₂]Cl + H₂O

[CH₂=NH₂]Cl + H₂CO + H₂O → [CH₃NH₃]Cl + HCOOH

The colorless hydrochloride salt can be converted to the amine by the addition of strong base, like NaOH:

[CH₃NH₃]Cl + NaOH → CH₃NH₂ + NaCl + H₂O

Another method entails reducing nitromethane with zinc and hydrochloric acid.

Reactivity and applications

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.

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.

Biological chemistry

Methylamine arises as a result of putrefaction and is a substrate for methanogenesis.

Additionally, methylamine is produced during PADI4-dependent arginine demethylation.

Safety

The LD₅₀ (mouse, s.c.) is 2.5 g/kg.

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.

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.

See also

• Methylammonium halide