Ethanolamine(2-aminoethanol,monoethanolamine,ETA,orMEA) is a naturally occurringorganic chemical compoundwith the formulaHOCH
2CH
2NH
2orC
2H
7NO.[8]The molecule isbifunctional,containing both aprimary amineand aprimary alcohol.Ethanolamine is acolorless,viscousliquidwith anodorreminiscent ofammonia.[9]
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| Names | |
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| Preferred IUPAC name
2-Aminoethan-1-ol[1] | |
Other names
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| Identifiers | |
3D model (JSmol)
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| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| DrugBank | |
| ECHA InfoCard | 100.004.986 |
| EC Number |
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| KEGG | |
PubChemCID
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| RTECS number |
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| UNII | |
CompTox Dashboard(EPA)
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| Properties | |
| C2H7NO | |
| Molar mass | 61.084g·mol−1 |
| Appearance | Viscous colourless liquid |
| Odor | Unpleasantammonia-like odour |
| Density | 1.0117g/cm3 |
| Melting point | 10.3 °C (50.5 °F; 283.4 K) |
| Boiling point | 170 °C (338 °F; 443 K) |
| Miscible | |
| Vapor pressure | 64Pa (20°C)[2] |
| Acidity(pKa) | 9.50[3] |
Refractive index(nD)
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1.4539 (20°C)[4] |
| Hazards | |
| GHSlabelling: | |
 
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| Danger | |
| H302,H312,H314,H332,H335,H412[5] | |
| P261,P273,P303+P361+P353,P305+P351+P338[5] | |
| NFPA 704(fire diamond) | |
| Flash point | 85 °C (185 °F; 358 K) (closed cup) |
| 410 °C (770 °F; 683 K) | |
| Explosive limits | 5.5–17% |
| Lethal doseor concentration (LD, LC): | |
LD50(median dose)
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| NIOSH(US health exposure limits): | |
PEL(Permissible)
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TWA: 3 ppm (6 mg/m3)[6] |
REL(Recommended)
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IDLH(Immediate danger)
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30ppm[6] |
| Safety data sheet(SDS) | Sigma[5] |
| Related compounds | |
Related compounds
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Except where otherwise noted, data are given for materials in theirstandard state(at 25 °C [77 °F], 100 kPa).
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Ethanolamine is commonly called monoethanolamine or MEA in order to be distinguished fromdiethanolamine(DEA) andtriethanolamine(TEOA). The ethanolamines comprise a group ofamino alcohols.A class ofantihistaminesis identified as ethanolamines, which includescarbinoxamine,clemastine,dimenhydrinate,chlorphenoxamine,diphenhydramineanddoxylamine.[10]
History
editEthanolamines, or in particular, their salts, were discovered byCharles Adolphe Wurtzin 1860[11]by heating2-chloroethanolwithammonia solutionwhile studying derivatives ofethylene oxidehe discovered a year earlier.[12]He wasn't able to separate the salts or isolate any free bases.
In 1897Ludwig Knorrdeveloped the modern industrial route (seebelow) and separated the products, including MEA, byfractional distillation,for the first time studying their properties.[13]
None of the ethanolamines were of any commercial importance until after the WWII industrial production of ethylene oxide took off.[12]
Occurrence in nature
editMEA molecules are a component in the formation of cellular membranes and are thus a molecular building block for life. Ethanolamine is the second-most-abundant head group forphospholipids,substances found inbiological membranes(particularly those of prokaryotes); e.g.,phosphatidylethanolamine.It is also used in messenger molecules such aspalmitoylethanolamide,which has an effect on CB1 receptors.[14]
MEA was thought to exist only on Earth and on certain asteroids, but in 2021 evidence was found that these molecules exist in interstellar space.[15]
Ethanolamine isbiosynthesizedby decarboxylation ofserine:[16]
- HOCH
2CH(CO
2H)NH
2→HOCH
2CH
2NH
2+ CO2
Derivatives of ethanolamine are widespread in nature; e.g.,lipids,asprecursorof a variety ofN-acylethanolamines(NAEs), that modulate severalanimalandplantphysiologicalprocesses such as seedgermination,plant–pathogeninteractions,chloroplastdevelopment andflowering,[17]as well as precursor, combined witharachidonic acidC
20H
32O
220:4,ω-6), to form the endocannabinoidanandamide(AEA:C
22H
37NO
2;20:4, ω-6).[18]
MEA is biodegraded byethanolamine ammonia-lyase,a B12-dependent enzyme. It is converted toacetaldehydeandammoniavia initial H-atom abstraction.[19]
- H2NCH2CH2OH → NH3+ CH3CHO
Industrial production
editMonoethanolamine is produced by treatingethylene oxidewith aqueousammonia;the reaction also producesdiethanolamineandtriethanolamine.The ratio of the products can be controlled by thestoichiometryof the reactants.[20]
Applications
editMEA is used asfeedstockin the production ofdetergents,emulsifiers,polishes, pharmaceuticals, corrosion inhibitors, and chemical intermediates.[9]
For example, reacting ethanolamine withammoniagivesethylenediamine,a precursor of the commonly usedchelating agent,EDTA.[20]
Gas stream scrubbing
editMonoethanolamines can scrub combusted-coal, combusted-methane and combusted-biogas flue emissions ofcarbon dioxide(CO2) very efficiently. MEA carbon dioxide scrubbing is also used to regenerate the air on submarines.
Solutions of MEA inwaterare used as a gas stream scrubbingliquidinamine treaters.[21]For example, aqueous MEA is used to removecarbon dioxide(CO2) andhydrogen sulfide(H2S) from various gas streams; e.g.,flue gasandsour natural gas.[22]The MEA ionizes dissolvedacidiccompounds, making thempolarand considerably moresoluble.
MEA scrubbing solutions can be recycled through a regeneration unit. When heated, MEA, being a rather weak base, will release dissolvedH2Sor CO2gas resulting in a pure MEA solution.[20][23]
Other uses
editIn pharmaceutical formulations, MEA is used primarily for buffering or preparation of emulsions. MEA can be used as pH regulator in cosmetics.[24]
It is an injectablesclerosantas a treatment option of symptomatic hemorrhoids. 2–5 ml of ethanolamine oleate can be injected into the mucosa just above the hemorrhoids to cause ulceration and mucosal fixation thus preventing hemorrhoids from descending out of the anal canal.
It is also an ingredient in cleaning fluid for automobilewindshields.[25]
pH-control amine
editEthanolamine is often used for alkalinization of water in steam cycles of power plants, including nuclearpower plantswithpressurized water reactors.This alkalinization is performed to control corrosion of metal components. ETA (or sometimes a similar organic amine; e.g.,morpholine) is selected because it does not accumulate in steam generators (boilers) andcrevicesdue to its volatility, but rather distributes relatively uniformly throughout the entire steam cycle. In such application, ETA is a key ingredient of so-called "all-volatile treatment" of water (AVT).[citation needed]
Reactions
editUpon reaction withcarbon dioxide,2 equivalents of ethanolamine react through the intermediacy ofcarbonic acidto form acarbamatesalt,[26]which when heated usually reforms back to ethanolamine and carbon dioxide but occasionally can also cyclizate to2-oxazolidone,generating amine gas treatment wastes.[27]
References
edit- ^abNomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book).Cambridge:The Royal Society of Chemistry.2014. pp. 649, 717.doi:10.1039/9781849733069-FP001.ISBN978-0-85404-182-4.
For example, the name 'ethanolamine', which is still widely used, is badly constructed because of the presence of two suffixes; it is not an alternative to the preferred IUPAC name, '2-aminoethan-1-ol'.
- ^"Ethanolamine MSDS"(PDF).Acros Organics.Archived fromthe original(PDF)on 2011-07-15.
- ^Hall, H.K. (1957)."Correlation of the Base Strengths of Amines".J. Am. Chem. Soc.79(20): 5441–4.doi:10.1021/ja01577a030.
- ^Reitmeier, R.E.; Sivertz, V.; Tartar, H.V. (1940). "Some Properties of Monoethanolamine and its Aqueous Solutions".Journal of the American Chemical Society.62(8): 1943–44.doi:10.1021/ja01865a009.
- ^abcSigma-Aldrich Co.,Ethanolamine.Retrieved on 2018-05-24.
- ^abcNIOSH Pocket Guide to Chemical Hazards."#0256".National Institute for Occupational Safety and Health(NIOSH).
- ^"Ethanolamine".Immediately Dangerous to Life or Health Concentrations (IDLH).National Institute for Occupational Safety and Health(NIOSH).
- ^"National Library of Medicine. PubChem. Ethanolomine".NIH, National Library of Medicine.RetrievedSeptember 5,2021.
- ^abMartin Ernst; Johann-Peter Melder; Franz Ingo Berger; Christian Koch (2022). "Ethanolamines and Propanolamines".Ullmann's Encyclopedia of Industrial Chemistry.Weinheim: Wiley-VCH.doi:10.1002/14356007.a10_001.pub2.ISBN978-3527306732.
- ^Cough, Cold, and Allergy Preparation ToxicityateMedicine
- ^Wurtz, A. (1860)."Synthese sauerstoffhaltiger Basen".Justus Liebigs Annalen der Chemie.114(1): 51–54.doi:10.1002/jlac.18601140106.ISSN0075-4617.
- ^abU.S. patent 9227912B2
- ^Knorr, Ludwig (1897)."Ueber den Amidoäthylalkohol".Berichte der deutschen chemischen Gesellschaft.30(1): 909–915.doi:10.1002/cber.189703001178.ISSN0365-9496.
- ^Calignano, A; La Rana, G; Piomelli, D (2001)."Antinociceptive activity of the endogenous fatty acid amide, palmitylethanolamide".European Journal of Pharmacology.419(2–3): 191–8.doi:10.1016/S0014-2999(01)00988-8.PMID11426841.
- ^"First evidence of cell membrane molecules in space".Astronomy Magazine.May 28, 2021.RetrievedSeptember 4,2021.
- ^"Phosphatidylethanolamine and related lipids".AOCS. Archived fromthe originalon 2012-08-21.Retrieved2015-08-09.
- ^Coutinho, Bruna G.; Mevers, Emily; Schaefer, Amy L.; Pelletier, Dale A.;Harwood, Caroline S.;Clardy, Jon; Greenberg, E. Peter (2018-09-25)."A plant-responsive bacterial-signaling system senses an ethanolamine derivative".Proceedings of the National Academy of Sciences of the United States of America.115(39): 9785–9790.Bibcode:2018PNAS..115.9785C.doi:10.1073/pnas.1809611115.ISSN0027-8424.PMC6166808.PMID30190434.
- ^Marzo, V. Di; Petrocellis, L. De; Sepe, N.; Buono, A. (1996-06-15)."Biosynthesis of anandamide and related acylethanolamides in mouse J774 macrophages and N18 neuroblastoma cells".Biochemical Journal.316(Pt 3): 977–84.doi:10.1042/bj3160977.PMC1217444.PMID8670178.
- ^Shibata, Naoki; Tamagaki, Hiroko; Hieda, Naoki; Akita, Keita; Komori, Hirofumi; Shomura, Yasuhito; Terawaki, Shin-Ichi; Mori, Koichi; Yasuoka, Noritake; Higuchi, Yoshiki; Toraya, Tetsuo (2010)."Crystal Structures of Ethanolamine Ammonia-lyase Complexed with Coenzyme B12 Analogs and Substrates".Journal of Biological Chemistry.285(34): 26484–26493.doi:10.1074/jbc.M110.125112.PMC2924083.PMID20519496.
- ^abcWeissermel, Klaus; Arpe, Hans-Jürgen; Lindley, Charlet R.; Hawkins, Stephen (2003). "Chap. 7. Oxidation Products of Ethylene".Industrial Organic Chemistry.Wiley-VCH.pp. 159–161.ISBN3-527-30578-5.
- ^Chremos A, et al. (August 2015)."Modelling the phase and chemical equilibria of aqueous solutions of alkanolamines and carbon dioxide using the SAFT-γ SW group contribution approach".Fluid Phase Equilibria.407:280.doi:10.1016/j.fluid.2015.07.052.hdl:10044/1/25382.
- ^Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants.2007.doi:10.17226/11170.ISBN978-0-309-09225-8.
- ^"Ethanolamine".Occupational Safety & Health Administration.Archived fromthe originalon 2013-05-03.Retrieved2008-05-11.
- ^Carrasco, F. (2009). "Ingredientes Cosméticos".Diccionario de Ingredientes Cosméticos 4ª Ed.www.imagenpersonal.net. p. 306.ISBN978-84-613-4979-1.
- ^Federal Motor Vehicle Safety Standards.U.S. Department of Transportation, National Highway Traffic Safety Administration. 1994. p. Part 571; S 108—PRE 128.
- ^Lu, Yanyue; Liao, Anping; Yun, Zhuge; Liang, Yanqing; Yao, Qinmei (2014)."Absorption of Carbon Dioxide in Ethanolamine Solutions".Asian Journal of Chemistry.26(1): 39–42.doi:10.14233/ajchem.2014.15301.
- ^Salim, S. R. S. (2021-03-01)."Treatment of amine wastes generated in industrial processes".IOP Conference Series: Materials Science and Engineering.1092(1): 012051.doi:10.1088/1757-899x/1092/1/012051.ISSN1757-8981.