Methylamine


Methylamine
Methylamine
Identifiers
CAS number 74-89-5 YesY
PubChem 6329
ChemSpider 6089 YesY
DrugBank DB01828
KEGG C00218 YesY
ChEBI CHEBI:16830 N
ChEMBL CHEMBL43280 YesY
RTECS number PF6300000
Jmol-3D images Image 1
Properties
Molecular formula CH5N
Molar mass 31.06 g mol−1
Appearance Colorless Gas
Density d40.699 (−10.8 °C) / 0.902 g/cm³, 40w/w% in water
Melting point

−94 °C (179.15 K)

Boiling point

−6 °C (267.2 K)

Solubility in water 108 g/100 mL (20 °C)
Acidity (pKa) 10.62 for MeNH3+[1]
Viscosity 0.23 cP at 0 °C
Structure
Molecular shape tetrahedral
Dipole moment 1.31 D (gas)
Hazards
MSDS From EMD Chemicals [1]
R-phrases 11-36/37 (40% solution in water)
Main hazards Corrosive liquid and gas,
inhalation hazard, flammable.
NFPA 704
NFPA 704.svg
4
3
0
Flash point 8 °C
Related compounds
Related amines Ammonia
dimethylamine
trimethylamine
 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.[2]

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.[3]

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.[4]

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.[5]

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.[5]

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.[6] Methylamine can also be used for scavenging H2S from hydrocarbon in refining applications.

Biological chemistry

Methylamine arises naturally as the result of putrefaction and is a substrate for methanogenesis.[7] It serves as a buffering agent in the lumen of the chloroplast in plants, effectively siphoning off protons that are heading for ATP synthase.[citation needed]

Safety

The LD50 (mouse) is 2400 mg/m3. Methylamine is also controlled as a List 1 substance by the United States Drug Enforcement Administration (DEA); the DEA lists methylamine as a precursor (to methamphetamine).

References

  1. ^ Hall, H.K., J. Am. Chem. Soc., 1957, 79, 5441.
  2. ^ 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. 
  3. ^ 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. 
  4. ^ 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 
  5. ^ a b Karsten Eller, Erhard Henkes, Roland Rossbacher, Hartmut Höke "Amines, Aliphatic" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2005.
  6. ^ H. D. Gibbs (1906). "Liquid methylamine as a solvent, and a study of its chemical reactivity". J. Am. Chem. Soc. 28: 1395–1422. doi:10.1021/ja01976a009. 
  7. ^ Thauer, R. K., "Biochemistry of Methanogenesis: a Tribute to Marjory Stephenson", Microbiology, 1998, 144, 2377-2406.

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  • Methylamine — Meth yl*am ine (? or ?), n. (Chem.) See {Methyl amine}, under {Methyl}. [1913 Webster] …   The Collaborative International Dictionary of English

  • Methylamine — Methylamine, organische Basen, die sich vom Ammoniak (NH3) ableiten, indem ein oder mehrere Atome Wasserstoff durch Methyl CH3 vertreten werden. Methylamin (Monomethylami) NH2CH3 findet sich in Mercurialis annua und M. perennis, im rohen… …   Meyers Großes Konversations-Lexikon

  • Methylamine — Methylamine, übelriechende, organische Verbindungen, die sich vom Ammoniak ableiten. [424] Man unterscheidet Mono , Di und Trimethylamine. Die letzteren beiden Verbindungen kommen in der Heringslake vor und finden als Zusätze zu Fischködern… …   Lexikon der gesamten Technik

  • methylamine — [meth΄əl ə mēn′, meth΄əl am′ēn΄] n. [ METHYL + AMINE] a colorless, flammable gas, CH3NH2, that smells like ammonia and is usually prepared synthetically by heating methanol with ammonia under pressure in the presence of a catalyst: it is used in… …   English World dictionary

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  • methylamine — noun Etymology: International Scientific Vocabulary Date: circa 1850 a flammable explosive gas CH3NH2 with a strong ammoniacal odor used especially in organic synthesis (as of dyes and insecticides) …   New Collegiate Dictionary

  • methylamine — /meth euh leuh meen , euhl am in/, n. Chem. any of three derivatives of ammonia in which one or all of the hydrogen atoms are replaced by methyl groups, esp. a gas, CH5N, with an ammonialike odor, the simplest alkyl derivative of ammonia and,… …   Universalium


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