{{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 | ImageClass = skin-invert-image | ImageFile_Ref = {{chemboximage|correct|??}} | ImageSize = 200 | ImageName = Skeletal formula of methylamine with all explicit hydrogens added | ImageFileL1 = Methylamine-3D-balls.png | ImageClassL1 = bg-transparent | ImageFileL1_Ref = {{chemboximage|correct|??}} | ImageNameL1 = Ball and stick model of methylamine | ImageFileR1 = Methylamine-3D-vdW.png | ImageClassR1 = bg-transparent | 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 = 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 | C=1|H=5|N=1 | Appearance = Colorless gas | Odor = Fishy, ammoniacal | Density = 0.6562 g/cm<sup>3</sup> (at 25 °C) | MeltingPtK = 180.05 | BoilingPtK = 266.5 to 267.1 | Solubility = 1008 g/L (at 20 °C) | VaporPressure = 186.10 kPa (at 20 °C) | LogP = −0.472 | HenryConstant = 1.4 mmol/(Pa·kg) | ConjugateAcid = {{chem2|[CH3NH3]+}} (Methylammonium) | Viscosity = 230 μPa·s (at 0 °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 formula of {{chem2|CH5N|auto=1}} or {{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 dissolved in solution with 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 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 + 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 |last1=Snider |first1=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 |bibcode=2000JAChS.12211507S |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 methylethanolamines. Liquid methylamine has solvent properties analogous to those of 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.| bibcode = 1996JAChS.118.1997D}}</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 and ''N''-methylpyrrolidone. The preparation of some surfactants and photographic developers require methylamine as a building block.<ref name=Ullmann/>
== Safety == The LD<sub>50</sub> (mouse, 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 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 List 1 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 and Jesse Pinkman use aqueous methylamine as part of a process to synthesize methamphetamine in the AMC series ''Breaking Bad''.<ref>{{cite news |newspaper=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 |date=3 December 2013 |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:Alkylamines Category:1849 introductions Category:Organic compounds with 1 carbon atom Category:Substances discovered in the 19th century Category:Methyl compounds Category:Foul-smelling chemicals