Methylamine

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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)[2]
Preferred IUPAC name
Methanamine[1]
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
Std enthalpy of
formation
(ΔfH⦵298)
 −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)[3]
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)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
 TWA 10 ppm (12 mg/m3)[3]
REL (Recommended)
 TWA 10 ppm (12 mg/m3)[3]
IDLH
(Immediate danger)
 100 ppm[3]
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 ?)

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

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.[4]

CH3OH + NH3 → CH3NH2 + H2O

In this way, an estimated 115,000 tons were produced in 2005.[5]

Laboratory methods

Methylamine was first prepared in 1849 by

Charles-Adolphe Wurtz via the hydrolysis of methyl isocyanate and related compounds.[5][6] An example of this process includes the use of the Hofmann rearrangement, to yield methylamine from acetamide and bromine.[7][8]

In the laboratory, methylamine hydrochloride is readily prepared by various other methods. One method entails treating formaldehyde with ammonium chloride.[9]

[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.[10]

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

methylethanolamines. Liquid methylamine has solvent properties analogous to those of liquid ammonia.[12]

Representative commercially significant chemicals produced from methylamine include the pharmaceuticals

metham sodium, and the solvents N-methylformamide and N-methylpyrrolidone. The preparation of some surfactants and photographic developers require methylamine as a building block.[5]

Biological chemistry

Methylamine arises as a result of putrefaction and is a substrate for methanogenesis.[13]

Additionally, methylamine is produced during PADI4-dependent arginine demethylation.[14]

Safety

The LD50 (mouse, s.c.) is 2.5 g/kg.[15]

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.[16]

Regulation

In the United States, methylamine is controlled as a List 1 precursor chemical by the Drug Enforcement Administration[17] due to its use in the illicit production of methamphetamine.[18]

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.[19][20]

See also

References

  1. ISBN 978-0-85404-182-4
    .
  2. ^ "Methylamine Definition & Meaning". Retrieved 22 April 2022.
  3. ^ a b c d e NIOSH Pocket Guide to Chemical Hazards. "#0398". National Institute for Occupational Safety and Health (NIOSH).
  4. doi:10.1016/S0920-5861(97)00003-5
    .
  5. ^
    doi:10.1002/14356007.a02_001
  6. ^ 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).
  7. ISBN 9780582444072
    .
  8. ^ Cohen, Julius (1900). Practical Organic Chemistry (2nd ed.). London: Macmillan and Co., Limited. p. 72.
  9. ^ Marvel, C. S.; Jenkins, R. L. (1941). "Methylamine Hydrochloride". Organic Syntheses; Collected Volumes, vol. 1, p. 347.
  10. ^ Gatterman, Ludwig & Wieland, Heinrich (1937). Laboratory Methods of Organic Chemistry. Edinburgh, UK: R & R Clark, Limited. pp. 157–158.
  11. ISBN 9780470749050
    . ...an unhindered amine such as methylamine
  12. doi:10.1021/ja952634p
    .
  13. PMID 9782487
    .
  14. PMID 18923809
    .
  15. ^ The Merck Index, 10th Ed. (1983), p.864, Rahway: Merck & Co.
  16. ^ CDC - NIOSH Pocket Guide to Chemical Hazards
  17. ^ Title 21 Code of Federal Regulations
  18. PMID 6680736
    .
  19. Washington Post. Archived from the original
    on 3 February 2023.
  20. ^ Harnisch, Falk; Salthammer, Tunga. "The Chemistry of Breaking Bad". Chemistry Views. Chemistry Europe. Archived from the original on 8 February 2024.
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