Methylamine

Methylamine
Skeletal formula of methylamine with all explicit hydrogens added
Ball and stick model of methylamine
Ball and stick model of methylamine
Spacefill model of methylamine
Spacefill model of methylamine
Names
Pronunciation /ˌmɛθələˈmiːn/
(METH-ə-lə-MEEN), /ˌmɛθəˈlæmən/
(METH-ə-LA-mən), /məˈθɪləˌmiːn/
(mə-THIL-ə-meen)
Preferred IUPAC name
Methanamine
Other names
  • Aminomethane
  • Monomethylamine
Identifiers
3D model (JSmol)
3DMet
Abbreviations MMA
741851
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.000.746 Edit this at Wikidata
EC Number
  • 200-820-0
145
KEGG
MeSH methylamine
RTECS number
  • PF6300000
UNII
UN number 1061
  • InChI=1S/CH5N/c1-2/h2H2,1H3 checkY
    Key: BAVYZALUXZFZLV-UHFFFAOYSA-N checkY
  • CN
Properties
CH3NH2
Molar mass 31.058 g·mol−1
Appearance Colorless gas
Odor Fishy, ammoniacal
Density 0.6562 g/cm3 (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
1008 g/L (at 20 °C)
log P −0.472
Vapor pressure 186.10 kPa (at 20 °C)
1.4 mmol/(Pa·kg)
Acidity (pKa) 10.66
Conjugate acid [CH3NH3]+ (Methylammonium)
-27.0·10−6 cm3/mol
Viscosity 230 μPa·s (at 0 °C)
1.31 D
Thermochemistry
−23.5 kJ/mol
Hazards
GHS labelling:
GHS02: Flammable GHS05: Corrosive GHS07: Exclamation mark
Danger
H220, H315, H318, H332, H335
P210, P261, P280, P305+P351+P338, P410+P403
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g. propaneInstability 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
3
4
0
Flash point −10 °C; 14 °F; 263 K (liquid, gas is extremely flammable)
430 °C (806 °F; 703 K)
Explosive limits 4.9–20.7%
Lethal dose or concentration (LD, LC):
100 mg/kg (oral, rat)
1860 ppm (mouse, 2 hr)
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 10 ppm (12 mg/m3)
REL (Recommended)
TWA 10 ppm (12 mg/m3)
IDLH (Immediate danger)
100 ppm
Safety data sheet (SDS) emdchemicals.com
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 checkY☒N ?)
Infobox references

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.

Methylamine 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 rotten fish. Methylamine is used as a building block for the synthesis of numerous other commercially available compounds.

Industrial production

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

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

Laboratory methods

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.

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

[NH4]Cl + CH2O → [CH2=NH2]Cl + H2O
[CH2=NH2]Cl + CH2O + H2O → [CH3NH3]Cl + HCOOH

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 entails reducing nitromethane with zinc and hydrochloric acid.

Another method of methylamine production is spontaneous decarboxylation of glycine with a strong base in water.[citation needed]

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.

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.

Regulation

In the United States, methylamine is controlled as a List 1 precursor chemical by the Drug Enforcement Administration due to its use in the illicit production of methamphetamine.

In popular culture

Fictional characters Walter White and Jesse Pinkman use methylamine as part of a process to synthesize methamphetamine in the AMC series Breaking Bad.

See also


This page was last updated at 2024-02-21 13:40 UTC. Update now. View original page.

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