Ethanolamine (2-aminoethanol, monoethanolamine, ETA, or MEA) is a naturally occurring organic chemical compound with the formula HOCH
2CH
2NH
2 or C
2H
7NO.[8] The molecule is bifunctional, containing both a primary amine and a primary alcohol. Ethanolamine is a colorless, viscous liquid with an odor reminiscent of ammonia.[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 | |
PubChem CID
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| RTECS number |
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| C2H7NO | |
| Molar mass | 61.084 g·mol−1 |
| Appearance | Viscous colourless liquid |
| Odor | Unpleasant ammonia-like odour |
| Density | 1.0117 g/cm3 |
| Melting point | 10.3 °C (50.5 °F; 283.4 K) |
| Boiling point | 170 °C (338 °F; 443 K) |
| Miscible | |
| Vapor pressure | 64 Pa (20 °C)[2] |
| Acidity (pKa) | 9.50[3] |
Refractive index (nD)
|
1.4539 (20 °C)[4] |
| Hazards | |
| GHS labelling: | |
 
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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 dose or 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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30 ppm[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 their standard state (at 25 °C [77 °F], 100 kPa).
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Ethanolamine is commonly called monoethanolamine or MEA in order to be distinguished from diethanolamine (DEA) and triethanolamine (TEOA). The ethanolamines comprise a group of amino alcohols. A class of antihistamines is identified as ethanolamines, which includes carbinoxamine, clemastine, dimenhydrinate, chlorphenoxamine, diphenhydramine and doxylamine.[10]
History
editEthanolamines, or in particular, their salts, were discovered by Charles Adolphe Wurtz in 1860[11] by heating 2-chloroethanol with ammonia solution while studying derivatives of ethylene oxide he discovered a year earlier.[12] He wasn't able to separate the salts or isolate any free bases.
In 1897 Ludwig Knorr developed the modern industrial route (see below) and separated the products, including MEA, by fractional 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 for phospholipids, substances found in biological membranes (particularly those of prokaryotes); e.g., phosphatidylethanolamine. It is also used in messenger molecules such as palmitoylethanolamide, 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 is biosynthesized by decarboxylation of serine:[16]
- HOCH
2CH(CO
2H)NH
2 → HOCH
2CH
2NH
2 + CO2
Derivatives of ethanolamine are widespread in nature; e.g., lipids, as precursor of a variety of N-acylethanolamines (NAEs), that modulate several animal and plant physiological processes such as seed germination, plant–pathogen interactions, chloroplast development and flowering,[17] as well as precursor, combined with arachidonic acid C
20H
32O
2 20:4, ω-6), to form the endocannabinoid anandamide (AEA: C
22H
37NO
2; 20:4, ω-6).[18]
MEA is biodegraded by ethanolamine ammonia-lyase, a B12-dependent enzyme. It is converted to acetaldehyde and ammonia via initial H-atom abstraction.[19]
- H2NCH2CH2OH → NH3 + CH3CHO
Industrial production
editMonoethanolamine is produced by treating ethylene oxide with aqueous ammonia; the reaction also produces diethanolamine and triethanolamine. The ratio of the products can be controlled by the stoichiometry of the reactants.[20]
Applications
editMEA is used as feedstock in the production of detergents, emulsifiers, polishes, pharmaceuticals, corrosion inhibitors, and chemical intermediates.[9]
For example, reacting ethanolamine with ammonia gives ethylenediamine, a precursor of the commonly used chelating agent, EDTA.[20]
Gas stream scrubbing
editMonoethanolamines can scrub combusted-coal, combusted-methane and combusted-biogas flue emissions of carbon dioxide (CO2) very efficiently. MEA carbon dioxide scrubbing is also used to regenerate the air on submarines.
Solutions of MEA in water are used as a gas stream scrubbing liquid in amine treaters.[21] For example, aqueous MEA is used to remove carbon dioxide (CO2) and hydrogen sulfide (H2S) from various gas streams; e.g., flue gas and sour natural gas.[22] The MEA ionizes dissolved acidic compounds, making them polar and considerably more soluble.
MEA scrubbing solutions can be recycled through a regeneration unit. When heated, MEA, being a rather weak base, will release dissolved H2S or CO2 gas 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 injectable sclerosant as 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 automobile windshields.[25]
pH-control amine
editEthanolamine is often used for alkalinization of water in steam cycles of power plants, including nuclear power plants with pressurized 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) and crevices due 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 with carbon dioxide, 2 equivalents of ethanolamine react through the intermediacy of carbonic acid to form a carbamate salt,[26] which when heated usually reforms back to ethanolamine and carbon dioxide but occasionally can also cyclizate to 2-oxazolidone, generating amine gas treatment wastes.[27]
References
edit- ^ a b Nomenclature 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. ISBN 978-0-85404-182-4.
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 from the 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.
- ^ a b c Sigma-Aldrich Co., Ethanolamine. Retrieved on 2018-05-24.
- ^ a b c NIOSH 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. Retrieved September 5, 2021.
- ^ a b Martin 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. ISBN 978-3527306732.
- ^ Cough, Cold, and Allergy Preparation Toxicity at eMedicine
- ^ Wurtz, A. (1860). "Synthese sauerstoffhaltiger Basen". Justus Liebigs Annalen der Chemie. 114 (1): 51–54. doi:10.1002/jlac.18601140106. ISSN 0075-4617.
- ^ a b U.S. patent 9227912B2
- ^ Knorr, Ludwig (1897). "Ueber den Amidoäthylalkohol". Berichte der deutschen chemischen Gesellschaft. 30 (1): 909–915. doi:10.1002/cber.189703001178. ISSN 0365-9496.
- ^ 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. PMID 11426841.
- ^ "First evidence of cell membrane molecules in space". Astronomy Magazine. May 28, 2021. Retrieved September 4, 2021.
- ^ "Phosphatidylethanolamine and related lipids". AOCS. Archived from the original on 2012-08-21. Retrieved 2015-08-09.
- ^ 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. ISSN 0027-8424. PMC 6166808. PMID 30190434.
- ^ 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. PMC 1217444. PMID 8670178.
- ^ 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. PMC 2924083. PMID 20519496.
- ^ a b c Weissermel, Klaus; Arpe, Hans-Jürgen; Lindley, Charlet R.; Hawkins, Stephen (2003). "Chap. 7. Oxidation Products of Ethylene". Industrial Organic Chemistry. Wiley-VCH. pp. 159–161. ISBN 3-527-30578-5.
- ^ 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. ISBN 978-0-309-09225-8.
- ^ "Ethanolamine". Occupational Safety & Health Administration. Archived from the original on 2013-05-03. Retrieved 2008-05-11.
- ^ Carrasco, F. (2009). "Ingredientes Cosméticos". Diccionario de Ingredientes Cosméticos 4ª Ed. www.imagenpersonal.net. p. 306. ISBN 978-84-613-4979-1.
- ^ 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. ISSN 1757-8981.