View source for Methylamine

{{Short description|Organic ammonia derivative}}
{{Distinguish|Methenamine}}
{{Chembox
| pronounce      = {{IPAc-en|ˌ|m|ɛ|θ|ə|l|ə|ˈ|m|iː|n|}}<br/>({{Respell|METH|ə|lə|MEEN}}), {{IPAc-en|ˌ|m|ɛ|θ|ə|ˈ|l|æ|m|ə|n|}}<br/>({{Respell|METH|ə|LA|mən}}), {{IPAc-en|m|ə|ˈ|θ|ɪ|l|ə|ˌ|m|iː|n|}}<br/>({{Respell|mə|THIL|ə|meen}})<ref>{{cite web |url = https://www.dictionary.com/browse/methylamine |title = Methylamine Definition & Meaning |access-date = 22 April 2022 }}</ref>
| Verifiedfields = changed
| Watchedfields  = changed
| verifiedrevid  = 415838275
| ImageFile      = MeNH2.svg
| ImageFile_Ref  = {{chemboximage|correct|??}}
| ImageSize      = 200
| ImageName      = Skeletal formula of methylamine with all explicit hydrogens added
| ImageFileL1    = Methylamine-3D-balls.png
| ImageFileL1_Ref = {{chemboximage|correct|??}}
| ImageNameL1    = Ball and stick model of methylamine
| ImageFileR1    = Methylamine-3D-vdW.png
| ImageFileR1_Ref = {{chemboximage|correct|??}}
| ImageNameR1    = Spacefill model of methylamine
| PIN            = Methanamine<ref name=iupac2013>{{cite book | title = Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book) | publisher = [[Royal Society of Chemistry|The Royal Society of Chemistry]] | date = 2014 | location = Cambridge | page = 670 | doi = 10.1039/9781849733069-00648 | isbn = 978-0-85404-182-4}}</ref>
| OtherNames     = {{bulletedlist|Aminomethane|Monomethylamine}}
| Section1       = {{Chembox Identifiers
| Abbreviations = MMA
| CASNo = 74-89-5
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = BSF23SJ79E
| PubChem = 6329
| ChemSpiderID = 6089
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| EINECS = 200-820-0
| UNNumber = 1061
| DrugBank = DB01828
| DrugBank_Ref = {{drugbankcite|changed|drugbank}}
| KEGG = C00218
| KEGG_Ref = {{keggcite|correct|kegg}}
| MeSHName = methylamine
| ChEBI = 16830
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEMBL = 43280
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| RTECS = PF6300000
| Beilstein = 741851
| Gmelin = 145
| 3DMet = B00060
| SMILES = CN
| StdInChI = 1S/CH5N/c1-2/h2H2,1H3
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = BAVYZALUXZFZLV-UHFFFAOYSA-N
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
}}
| Section2       = {{Chembox Properties
| Formula = {{chem2|CH3NH2}}
| C=1|H=5|N=1
| Appearance = Colorless gas
| Odor = Fishy, ammoniacal
| Density = 0.6562 g/cm<sup>3</sup> (at 25&nbsp;°C)
| MeltingPtK = 180.05
| BoilingPtK = 266.5 to 267.1
| Solubility = 1008 g/L (at 20&nbsp;°C)
| VaporPressure = 186.10 kPa (at 20&nbsp;°C)
| LogP = −0.472
| HenryConstant = 1.4 mmol/(Pa·kg)
| ConjugateAcid = {{chem2|[CH3NH3]+}} ([[Methylammonium halide|Methylammonium]])
| Viscosity = 230 μPa·s (at 0&nbsp;°C)
| Dipole = 1.31 D
| pKa = 10.66
| MagSus = −27.0·10<sup>−6</sup> cm<sup>3</sup>/mol
}}
| Section3       = {{Chembox Thermochemistry
| DeltaHf = −23.5 kJ/mol
}}
| Section4       = {{Chembox Hazards
| ExternalSDS = [http://www.emdchemicals.com/analytics/doc/msds/msds-display.asp?materialid=MX0660&Div=2 emdchemicals.com]
| GHSPictograms = {{GHS flame}} {{GHS corrosion}} {{GHS exclamation mark}}
| GHSSignalWord = '''DANGER'''
| HPhrases = {{H-phrases|220|315|318|332|335}}
| PPhrases = {{P-phrases|210|261|280|305+351+338|410+403}}
| NFPA-H = 3
| NFPA-F = 4
| NFPA-R = 0
| FlashPtF = 14
| FlashPt_notes = (liquid, gas is extremely flammable)<ref name=PGCH/>
| AutoignitionPtC = 430
| ExploLimits = 4.9–20.7%
| LD50 = 100 mg/kg (oral, rat)
| PEL = TWA 10 ppm (12 mg/m<sup>3</sup>)<ref name=PGCH>{{PGCH|0398}}</ref>
| IDLH = 100 ppm<ref name=PGCH/>
| LC50 = 1860 ppm (mouse, 2 hr)<ref name=PGCH/>
| REL = TWA 10 ppm (12 mg/m<sup>3</sup>)<ref name=PGCH/>
}}
| Section5       = {{Chembox Related
| OtherFunction_label = alkanamines
| OtherFunction = [[ethylamine]], [[dimethylamine]], [[trimethylamine]]
| OtherCompounds = [[ammonia]]
}}
}}

'''Methylamine''', also known as '''methanamine''', is an [[organic compound]] with a [[chemical formula|formula]] of {{chem2|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.

== Production ==
=== Industrial production ===
Methylamine has been produced industrially since the 1920s (originally by [[Commercial Solvents Corporation]] for dehairing of animal skins).<ref name=":0" /> This was made possible by {{Interlanguage link|Kazimierz Smoleński|pl}} and his wife Eugenia who discovered amination of alcohols, including methanol, on alumina or kaolin catalyst after WWI, filed two patent applications in 1919<ref>{{Patent|PL|90B1|application}}, {{Patent|PL|91B1|application}}, https://uprp.gov.pl/sites/default/files/2019-12/KWARTALNIK_100_lat_wydanie_specjalne.pdf</ref> and published an article in 1921.<ref name=":0" /><ref>{{Cite book |last=Not Available |url=http://archive.org/details/in.ernet.dli.2015.48294 |title=Chemical Abstracts (1922) Vol.16, No.18 |date=1922}}</ref>

It is now prepared commercially by the reaction of [[ammonia]] with [[methanol]] in the presence of an [[Amorphous silica-alumina|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.<ref name=":0">{{cite journal
|author1=Corbin D.R. |author2=Schwarz S. |author3=Sonnichsen G.C. | title = Methylamines synthesis: A review
| journal = Catalysis Today
| year = 1997
| volume = 37
| issue = 24
| pages = 71–102
| doi = 10.1016/S0920-5861(97)00003-5 }}
</ref>
:{{chem2|CH3OH + NH3 → CH3NH2 + H2O}}
In this way, an estimated 115,000 tons were produced in 2005.<ref name=Ullmann/>

===Laboratory methods===
Methylamine was first prepared in 1849 by [[Charles-Adolphe Wurtz]] via the hydrolysis of [[methyl isocyanate]] and related compounds.<ref name=Ullmann>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}}</ref><ref>Charles-Adolphe Wurtz (1849) [http://gallica.bnf.fr/ark:/12148/bpt6k29859/f223.image.langEN "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).</ref> An example of this process includes the use of the [[Hofmann rearrangement]], to yield methylamine from [[acetamide]] and [[bromine]].<ref>{{cite book|last1= Mann |first1= F. G. |last2= Saunders |first2= B. C.|title=Practical Organic Chemistry|edition=4th|year=1960|publisher=Longman|location=London|isbn=9780582444072|pages=128|url=https://www.scribd.com/doc/46973684/Practical-Organic-Chemistry-Frederick-George-Mann}}</ref><ref>{{cite book|last=Cohen|first=Julius|title=Practical Organic Chemistry|edition=2nd|year=1900|publisher=Macmillan and Co., Limited|location=London|page=[https://archive.org/details/practicalorgani00cohegoog/page/n90 72]|url=https://archive.org/details/practicalorgani00cohegoog}}</ref>

In the laboratory, methylamine [[hydrochloride]] is readily prepared by various other methods. One method entails treating [[formaldehyde]] with [[ammonium chloride]].<ref>{{OrgSynth | author = Marvel, C. S. | author2 = Jenkins, R. L. | title = Methylamine Hydrochloride | collvol = 1 | collvolpages = 347 | year = 1941 | prep = cv1p0347}}</ref>
:{{chem2|[NH4]Cl + CH2O → [CH2\dNH2]Cl + H2O}}
:{{chem2|[CH2\dNH2]Cl + CH2O + H2O → [CH3NH3]Cl + [[formic acid|HCOOH]]}}
The colorless hydrochloride salt can be converted to an amine by the addition of a strong base, such as [[sodium hydroxide]] (NaOH):
:{{chem2|[CH3NH3]Cl + NaOH → CH3NH2 + NaCl + H2O}}

Another method entails reducing [[nitromethane]] with [[zinc]] and hydrochloric acid.<ref>{{cite book|author1=Gatterman, Ludwig |author2=Wieland, Heinrich |name-list-style=amp |title=Laboratory Methods of Organic Chemistry|year=1937|publisher=R & R Clark, Limited|location=Edinburgh, UK|pages=157–158|url=https://books.google.com/books?id=M94cMwEACAAJ&q=Laboratory+Methods+of+Organic+Chemistry+Gattermann+Wieland+Heinrich+1937}}</ref>

Another method of methylamine production is spontaneous decarboxylation of [[glycine]] with a strong base in water.<ref>{{Cite journal |last=Snider |first=Mark J. |last2=Wolfenden |first2=Richard |date=2000-11-03 |title=The Rate of Spontaneous Decarboxylation of Amino Acids |url=http://dx.doi.org/10.1021/ja002851c |journal=Journal of the American Chemical Society |volume=122 |issue=46 |pages=11507-11508 |doi=10.1021/ja002851c |issn=0002-7863|url-access=subscription }}</ref>

=== Biosynthesis ===
Methylamine arises as a result of [[putrefaction]] and is a substrate for [[methanogenesis]].<ref>{{Cite journal | doi = 10.1099/00221287-144-9-2377| title = Biochemistry of methanogenesis: A tribute to Marjory Stephenson:1998 Marjory Stephenson Prize Lecture| journal = Microbiology| volume = 144| issue = 9| pages = 2377–406| year = 1998| last1 = Thauer| first1 = R. K.| pmid=9782487| doi-access = free}}</ref>

Additionally, methylamine is produced during [[PADI4]]-dependent [[arginine]] [[demethylation]].<ref>{{cite journal|last1=Ng|first1=SS|last2=Yue|first2=WW|last3=Oppermann|first3=U|last4=Klose|first4=RJ|title=Dynamic protein methylation in chromatin biology.|journal=Cellular and Molecular Life Sciences|date=February 2009|volume=66|issue=3|pages=407–22|pmid=18923809|doi=10.1007/s00018-008-8303-z|pmc=2794343}}</ref>

== Reactivity and applications ==
Methylamine is a good [[nucleophile]] as it is an unhindered [[amine]].<ref>{{cite book | title = Linker Strategies in Solid-Phase Organic Synthesis | date = 13 October 2009 | editor = Peter Scott | url = https://books.google.com/books?id=yZlldxZKBNsC&q=methylamine+unhindered+base&pg=PA80 | page = 80 | publisher = John Wiley & Sons | isbn = 9780470749050 | quote = ...an unhindered amine such as methylamine}}</ref> 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 [[methylethanolamine]]s. Liquid methylamine has solvent properties analogous to those of [[Ammonia#Solvent|liquid ammonia]].<ref>{{Cite journal | doi = 10.1021/ja952634p| title = The Lithium−Sodium−Methylamine System: Does a Low-Melting Sodide Become a Liquid Metal?| journal = Journal of the American Chemical Society| volume = 118| issue = 8| pages = 1997| year = 1996| last1 = Debacker| first1 = Marc G.| last2 = Mkadmi| first2 = El Bachir| last3 = Sauvage| first3 = François X.| last4 = Lelieur| first4 = Jean-Pierre| last5 = Wagner| first5 = Michael J.| last6 = Concepcion| first6 = Rosario| last7 = Kim| first7 = Jineun| last8 = McMills| first8 = Lauren E. H.| last9 = Dye| first9 = James L.}}</ref>

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|''N''-methylformamide]] and [[N-Methyl-2-pyrrolidone|''N''-methylpyrrolidone]]. The preparation of some [[surfactant]]s and photographic developers require methylamine as a building block.<ref name=Ullmann/>

== Safety ==
The [[Median lethal dose|LD<sub>50</sub>]] (mouse, [[Subcutaneous administration|s.c.]]) is 2.5 g/kg.<ref>''The Merck Index'', 10th Ed. (1983), p.864, Rahway: Merck & Co.</ref>

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&nbsp;mg/m<sup>3</sup> over an eight-hour time-weighted average.<ref>[https://www.cdc.gov/niosh/npg/npgd0398.html CDC - NIOSH Pocket Guide to Chemical Hazards]</ref>

== Regulation ==
In the United States, methylamine is controlled as a [[DEA list of chemicals|List 1]] [[drug precursor|precursor]] chemical by the [[Drug Enforcement Administration]]<ref>[https://www.deadiversion.usdoj.gov/21cfr/cfr/1310/1310_02.htm Title 21 Code of Federal Regulations]</ref> due to its use in the illicit production of [[methamphetamine]].<ref>{{cite journal | doi = 10.1520/JFS12235J| title = The Clandestine Drug Laboratory Situation in the United States| journal = Journal of Forensic Sciences| volume = 28| pages = 18–31| year = 1983| last1 = Frank| first1 = R. S.| issue = 1| pmid = 6680736}}</ref>

== In popular culture ==
Fictional characters [[Walter White (Breaking Bad)|Walter White]] and [[Jesse Pinkman]] use [[Aqueous solution|aqueous]] methylamine as part of a process to synthesize [[methamphetamine]] in the [[AMC (TV channel)|AMC]] series ''[[Breaking Bad]]''.<ref>{{cite web |website=[[Washington Post]] |url=https://www.washingtonpost.com/news/wonk/wp/2013/08/15/heres-what-breaking-bad-gets-right-and-wrong-about-the-meth-business/ |title=Here’s what ‘Breaking Bad’ gets right, and wrong, about the meth business |date=15 August 2013 |last=Matthews |first=Dylan |archive-date=3 February 2023 |archive-url=https://web.archive.org/web/20230203140004/https://www.washingtonpost.com/news/wonk/wp/2013/08/15/heres-what-breaking-bad-gets-right-and-wrong-about-the-meth-business/}}</ref><ref>{{cite web |website=Chemistry Views |publisher=[[Chemistry Europe]] |title=The Chemistry of Breaking Bad |last1=Harnisch |first1=Falk |last2=Salthammer |first2=Tunga |archive-url=https://web.archive.org/web/20240208125657/https://www.chemistryviews.org/details/ezine/5416791/The_Chemistry_of_Breaking_Bad/ |archive-date=8 February 2024 |url=https://www.chemistryviews.org/details/ezine/5416791/The_Chemistry_of_Breaking_Bad/}}</ref>

==See also==
*[[Methylammonium halide]]

== References ==
{{Reflist}}
{{Molecules detected in outer space}}
{{Authority control}}

[[Category:Organonitrogen compounds]]
[[Category:Alkylamines]]
[[Category:1849 introductions]]
[[Category:Organic compounds with 1 carbon atom]]
[[Category:Substances discovered in the 19th century]]
[[Category:Methyl compounds]]