ethanolamine

Ethanolamines, or in particular, their salts, were discovered by Charles Adolphe Wurtz in 1860{{Cite journal |last=Wurtz |first=A. |date=1860 |title=Synthese sauerstoffhaltiger Basen |url=https://books.google.com/books?id=B9TyAAAAMAAJ&pg=RA1-PA51 |journal=Justus Liebigs Annalen der Chemie |language=en |volume=114 |issue=1 |pages=51–54 |doi=10.1002/jlac.18601140106 |issn=0075-4617}} by heating 2-chloroethanol with ammonia solution while studying derivatives of ethylene oxide he discovered a year earlier.{{US patent|9227912B2}} 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.{{Cite journal |last=Knorr |first=Ludwig |date=1897 |title=Ueber den Amidoäthylalkohol |url=https://books.google.com/books?id=vxvzAAAAMAAJ&pg=PA909 |journal=Berichte der Deutschen Chemischen Gesellschaft |language=en |volume=30 |issue=1 |pages=909–915 |doi=10.1002/cber.189703001178 |issn=0365-9496}}

None of the ethanolamines were of any commercial importance until after the WWII industrial production of ethylene oxide took off.

MEA 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.{{cite journal | doi = 10.1016/S0014-2999(01)00988-8 | title = Antinociceptive activity of the endogenous fatty acid amide, palmitylethanolamide | year = 2001 | last1 = Calignano | first1 = A | journal = European Journal of Pharmacology | volume = 419 | issue = 2–3 | pages = 191–8 | pmid = 11426841 | last2 = La Rana | first2 = G | last3 = Piomelli | first3 = D| url = https://escholarship.org/uc/item/9js9j6f1}}

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.{{Cite web|date=May 28, 2021|title=First evidence of cell membrane molecules in space|url=https://astronomy.com/news/2021/05/first-evidence-of-cell-membrane-molecules-in-space|access-date=September 4, 2021|website=Astronomy Magazine}}

Ethanolamine is biosynthesized by decarboxylation of serine:{{Cite web |title=Phosphatidylethanolamine and related lipids |publisher=AOCS |url=http://lipidlibrary.aocs.org/Lipids/pe/index.htm |access-date=2015-08-09 |archive-url=https://web.archive.org/web/20120821202641/http://lipidlibrary.aocs.org/lipids/pe/index.htm |archive-date=2012-08-21 |url-status=dead}}

:{{chem|HOCH|2|CH(CO|2|H)NH|2}} → {{chem|HOCH|2|CH|2|NH|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,{{Cite journal|last1=Coutinho|first1=Bruna G.|last2=Mevers|first2=Emily|last3=Schaefer|first3=Amy L.|last4=Pelletier|first4=Dale A.|author-link5=Caroline Harwood|last5=Harwood|first5=Caroline S.|last6=Clardy|first6=Jon|last7=Greenberg|first7=E. Peter|date=2018-09-25|title=A plant-responsive bacterial-signaling system senses an ethanolamine derivative|journal=Proceedings of the National Academy of Sciences of the United States of America|volume=115|issue=39|pages=9785–9790|doi=10.1073/pnas.1809611115|issn=0027-8424|pmc=6166808|pmid=30190434|bibcode=2018PNAS..115.9785C |doi-access=free}} as well as precursor, combined with arachidonic acid {{chem|C|20|H|32|O|2}} 20:4, ω-6), to form the endocannabinoid anandamide (AEA: {{chem|C|22|H|37|NO|2}}; 20:4, ω-6).{{Cite journal|last1=Marzo|first1=V. Di|last2=Petrocellis|first2=L. De|last3=Sepe|first3=N.|last4=Buono|first4=A.|date=1996-06-15|title=Biosynthesis of anandamide and related acylethanolamides in mouse J774 macrophages and N18 neuroblastoma cells.|journal=Biochemical Journal|volume=316|issue=Pt 3|pages=977–84|doi=10.1042/bj3160977|pmid=8670178|pmc=1217444}}

MEA is biodegraded by ethanolamine ammonia-lyase, a B12-dependent enzyme. It is converted to acetaldehyde and ammonia via initial H-atom abstraction.{{cite journal |doi=10.1074/jbc.M110.125112 |doi-access=free |title=Crystal Structures of Ethanolamine Ammonia-lyase Complexed with Coenzyme B12 Analogs and Substrates |date=2010 |last1=Shibata |first1=Naoki |last2=Tamagaki |first2=Hiroko |last3=Hieda |first3=Naoki |last4=Akita |first4=Keita |last5=Komori |first5=Hirofumi |last6=Shomura |first6=Yasuhito |last7=Terawaki |first7=Shin-Ichi |last8=Mori |first8=Koichi |last9=Yasuoka |first9=Noritake |last10=Higuchi |first10=Yoshiki |last11=Toraya |first11=Tetsuo |journal=Journal of Biological Chemistry |volume=285 |issue=34 |pages=26484–26493 |pmid=20519496 |pmc=2924083 }}

:{{chem2|H2NCH2CH2OH -> NH3 + CH3CHO}}

Monoethanolamine 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.

:File:Reaction of ethylene oxide with ammonia.svg

MEA is used as feedstock in the production of detergents, emulsifiers, polishes, pharmaceuticals, corrosion inhibitors, and chemical intermediates.

For example, reacting ethanolamine with ammonia gives ethylenediamine, a precursor of the commonly used chelating agent, EDTA.

:File:En from ethanolamine.png

{{see also|carbon dioxide scrubber|sour gas}}

Monoethanolamines 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.{{cite journal | vauthors = Chremos A, et al. | title = Modelling the phase and chemical equilibria of aqueous solutions of alkanolamines and carbon dioxide using the SAFT-γ SW group contribution approach | journal = Fluid Phase Equilibria | volume = 407 | pages = 280–297 | date = August 2015 | doi = 10.1016/j.fluid.2015.07.052 | doi-access = free | hdl = 10044/1/25382 | hdl-access = free }} 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.{{Cite book | url=http://www.nap.edu/openbook.php?record_id=11170 |doi = 10.17226/11170|title = Emergency and Continuous Exposure Guidance Levels for Selected Submarine Contaminants|year = 2007|isbn = 978-0-309-09225-8}} 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.{{cite book | title = Industrial Organic Chemistry |first1=Klaus |last1=Weissermel |first2=Hans-Jürgen |last2=Arpe |first3=Charlet R. |last3=Lindley |first4=Stephen |last4=Hawkins | publisher = Wiley-VCH | year = 2003 | isbn = 3-527-30578-5 | pages = 159–161 | chapter = Chap. 7. Oxidation Products of Ethylene}}{{cite web | publisher = Occupational Safety & Health Administration | url = http://www.osha.gov/SLTC/healthguidelines/ethanolamine/recognition.html | title = Ethanolamine | access-date = 2008-05-11 | archive-url = https://web.archive.org/web/20130503160502/http://www.osha.gov/SLTC/healthguidelines/ethanolamine/recognition.html | archive-date = 2013-05-03 | url-status = dead}}

In pharmaceutical formulations, MEA is used primarily for buffering or preparation of emulsions. MEA can be used as pH regulator in cosmetics.{{cite book | title = Diccionario de Ingredientes Cosméticos 4ª Ed |first=F. |last=Carrasco| publisher = www.imagenpersonal.net | year = 2009 | isbn = 978-84-613-4979-1 | pages = 306 | chapter = Ingredientes Cosméticos}}

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.{{cite book |url=https://books.google.com/books?id=swgeJm6aAC0C&pg=RA7-PA128 |title=Federal Motor Vehicle Safety Standards |year=1994 |page=Part 571; S 108—PRE 128 |publisher=U.S. Department of Transportation, National Highway Traffic Safety Administration}}

Ethanolamine 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|date=July 2015}}

Upon reaction with carbon dioxide, 2 equivalents of ethanolamine react through the intermediacy of carbonic acid to form a carbamate salt,{{cite journal |first1=Yanyue |last1=Lu |first2=Anping |last2=Liao |first3=Zhuge |last3=Yun |first4=Yanqing |last4=Liang |first5=Qinmei |last5=Yao |title=Absorption of Carbon Dioxide in Ethanolamine Solutions |journal=Asian Journal of Chemistry |volume=26 |issue=1 |pages=39–42 |date=2014 |doi=10.14233/ajchem.2014.15301 |url=https://asianjournalofchemistry.co.in/User/ViewFreeArticle.aspx?ArticleID=26_2_11|doi-access=free}} which when heated usually reforms back to ethanolamine and carbon dioxide but occasionally can also cyclizate to 2-oxazolidone, generating amine gas treatment wastes.{{Cite journal |last=Salim |first=S. R. S. |date=2021-03-01 |title=Treatment of amine wastes generated in industrial processes. |journal=IOP Conference Series: Materials Science and Engineering |volume=1092 |issue=1 |pages=012051 |doi=10.1088/1757-899x/1092/1/012051 |issn=1757-8981|doi-access=free |bibcode=2021MS&E.1092a2051S }}

{{reflist}}

• [https://web.archive.org/web/20150402110306/http://www.inclusive-science-engineering.com/process-technology-to-produce-ethanolamines-by-reaction-of-ammonia-and-ethylene-oxide/ Process technology to produce ethanolamines by reaction of ammonia and ethylene oxide]
• [https://www.cdc.gov/niosh/npg/npgd0256.html CDC - NIOSH Pocket Guide to Chemical Hazards]

Category:Primary alcohols

Category:Commodity chemicals