Methylamine

From Wikipedia, the free encyclopedia - View original article

Methylamine
Identifiers
AbbreviationsMMA
CAS number74-89-5 YesY
PubChem6329
ChemSpider6089 YesY
EC number200-820-0
UN number1061
DrugBankDB01828
KEGGC00218 YesY
MeSHmethylamine
ChEBICHEBI:16830 N
ChEMBLCHEMBL43280 YesY
RTECS numberPF6300000
Beilstein Reference741851
Gmelin Reference145
3DMetB00060
Jmol-3D imagesImage 1
Properties
Molecular formulaCH5N
Molar mass31.06 g mol−1
AppearanceColorless gas
OdorFishy, 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 water1.08 kg L−1 (at 20 °C)
log P−0.472
Vapor pressure186.10 kPa (at 20 °C)
kH1.4 mmol Pa−1 kg−1
Viscosity230 μPa s (at 0 °C)
Dipole moment1.31 D
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−23.5 kJ mol−1
Hazards
MSDSemdchemicals.com
GHS pictogramsThe flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal wordDANGER
GHS hazard statementsH220, H315, H318, H332, H335
GHS precautionary statementsP210, P261, P280, P305+351+338, P410+403
EU Index612-001-00-9
EU classificationFlammable F+ Harmful Xn
R-phrasesR12, R20, R37/38, R41
S-phrases(S2), S16, S26, S39
NFPA 704
NFPA 704.svg
4
3
0
Flash point<−30 °C
Autoignition
temperature
430 °C
Explosive limits4.9–20.8%
LD50100 mg kg−1 (oral, rat)
Related compounds
Related alkanaminesethylamine, dimethylamine, trimethylamine
Related compoundsammonia
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
Jump to: navigation, search
Methylamine
Identifiers
AbbreviationsMMA
CAS number74-89-5 YesY
PubChem6329
ChemSpider6089 YesY
EC number200-820-0
UN number1061
DrugBankDB01828
KEGGC00218 YesY
MeSHmethylamine
ChEBICHEBI:16830 N
ChEMBLCHEMBL43280 YesY
RTECS numberPF6300000
Beilstein Reference741851
Gmelin Reference145
3DMetB00060
Jmol-3D imagesImage 1
Properties
Molecular formulaCH5N
Molar mass31.06 g mol−1
AppearanceColorless gas
OdorFishy, 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 water1.08 kg L−1 (at 20 °C)
log P−0.472
Vapor pressure186.10 kPa (at 20 °C)
kH1.4 mmol Pa−1 kg−1
Viscosity230 μPa s (at 0 °C)
Dipole moment1.31 D
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−23.5 kJ mol−1
Hazards
MSDSemdchemicals.com
GHS pictogramsThe flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The corrosion pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) The exclamation-mark pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)
GHS signal wordDANGER
GHS hazard statementsH220, H315, H318, H332, H335
GHS precautionary statementsP210, P261, P280, P305+351+338, P410+403
EU Index612-001-00-9
EU classificationFlammable F+ Harmful Xn
R-phrasesR12, R20, R37/38, R41
S-phrases(S2), S16, S26, S39
NFPA 704
NFPA 704.svg
4
3
0
Flash point<−30 °C
Autoignition
temperature
430 °C
Explosive limits4.9–20.8%
LD50100 mg kg−1 (oral, rat)
Related compounds
Related alkanaminesethylamine, dimethylamine, trimethylamine
Related compoundsammonia
 N (verify) (what is: YesY/N?)
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 sold 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

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.[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

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.

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]

Liquid methylamine can be used as a solvent analogous to liquid ammonia. It shares some of the properties of liquid ammonia, but is better for dissolving organic substances, in the same way that methanol is better than water.[5] Methylamine can also be used for scavenging H2S from hydrocarbon in refining applications.

Biological chemistry

Methylamine arises results from putrefaction and is a substrate for methanogenesis.[6]

Safety

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 (DEA); the DEA has listed methylamine as a precursor ingredient to methamphetamine.

References

  1. ^ S.N. Bizzari (November 2008). "CEH Marketing Research Report: ALKYLAMINES (C1-C6)". Chemical Economics Handbook. SRI consulting. http://www.sriconsulting.com/CEH/Private/Reports/611.5030//. Retrieved July 2011. 
  2. ^ 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. 
  3. ^ Marvel, C. S.; Jenkins, R. L. (1941), "Methylamine Hydrochloride", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv1p0347 ; Coll. Vol. 1: 347 
  4. ^ 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
  5. ^ H. D. Gibbs (1906). "Liquid methylamine as a solvent, and a study of its chemical reactivity". J. Am. Chem. Soc. 28 (10): 1395–1422. doi:10.1021/ja01976a009. 
  6. ^ Thauer, R. K., "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson", Microbiology, 1998, 144, 2377-2406.
  7. ^ The Merck Index, 10th Ed. (1983), p.864, Rahway: Merck & Co.