View source for Ethanol

{{Short description|Organic compound (CH3CH2OH)}}
{{For|ethanol as a drug or medicine|Alcohol (drug)|Alcohols (medicine)}}
{{Distinguish|Ethenol|Ethynol|Ethanal}}
{{pp-move|small=yes}}
{{Use dmy dates|date=December 2017}}

{{Chembox
| Verifiedfields = changed
| Watchedfields  = changed
| verifiedrevid  = 477167117
| ImageFileL1    = Ethanol-2D-flat.svg
| ImageNameL1    = Full structural formula of ethanol
| ImageClassL1   = skin-invert
| ImageFileR1    = Ethanol-2D-skeletal.svg
| ImageNameR1    = Skeletal formula of ethanol
| ImageClassR1   = skin-invert
| ImageFileL2    = Ethanol-3D-balls.png
| ImageClassL2 = bg-transparent
| ImageNameL2    = Ball-and-stick model of ethanol
| ImageFileR2    = Ethanol-3D-vdW.png
| ImageClassR2 = bg-transparent
| ImageNameR2    = Space-filling model of ethanol
| ImageFile3     = Sample of Absolute Ethanol.jpg
| ImageCaption3  = A bottle of ethanol
| PIN            = Ethanol<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, UK | page=30 | doi=10.1039/9781849733069-00001 | isbn=978-0-85404-182-4}}</ref>
| pronounce      = {{IPAc-en|ˈ|ɛ|θ|ə|n|ɒ|l}}
| OtherNames     = {{ubl|Absolute alcohol|Alcohol|Cologne spirit|Drinking alcohol|Ethylic alcohol|EtOH|Ethyl alcohol|Ethyl hydroxide|Ethylene hydrate|Ethylol|Grain alcohol|Hydroxyethane|Methylcarbinol}}
| Section2       = {{Chembox Properties
|C=2 | H=6 | O=1
|MolarMass = {{Chem molar mass|C=2|H=6|O=1|unit=g/mol}}
|Appearance = Colorless liquid
|Odor = wine-like, pungent<ref name="pubchem">{{cite web | title=Ethanol | url=https://pubchem.ncbi.nlm.nih.gov/compound/Ethanol | website=PubChem | access-date=29 December 2022}}</ref>
|Density = 0.78945 g/cm<sup>3</sup> (at 20 °C)<ref name=crc2>{{RubberBible92nd|page=3.246}}</ref>
|MeltingPtC = −114.14 ± 0.03<ref name="crc2" />
|BoilingPtC = 78.23 ± 0.09<ref name="crc2" />
|Solubility = [[Miscibility|Miscible]]
|RefractIndex = 1.3611<ref name="crc2" />
|LogP = −0.18
|VaporPressure = 5.95 kPa (at 20&nbsp;°C)
|pKa = 15.9 (H<sub>2</sub>O), 29.8 (DMSO)<ref>{{cite journal | vauthors=Ballinger P, Long FA | doi=10.1021/ja01489a008 | title=Acid Ionization Constants of Alcohols. II. Acidities of Some Substituted Methanols and Related Compounds1,2 | year=1960 | journal=Journal of the American Chemical Society | volume=82 | issue=4 | pages=795–798 | bibcode=1960JAChS..82..795B | issn=0002-7863}}</ref><ref>{{cite journal | vauthors=Arnett EM, Venkatasubramaniam KG | doi=10.1021/jo00158a001 | journal=J. Org. Chem. | title=Thermochemical acidities in three superbase systems | year=1983 | volume=48 | issue=10 | pages=1569–1578}}</ref>
|Viscosity = 1.2 mPa·s (at 20&nbsp;°C), 1.074 mPa·s (at 25&nbsp;°C)<ref name=crc92>{{Cite book | editor-last=Lide | editor-first=David R. | name-list-style=vanc | title=CRC Handbook of Chemistry and Physics | url={{google books | plainurl=y | id=pYPRBQAAQBAJ | page=6}} | edition=92 | year=2012 | publisher=CRC Press/Taylor and Francis | location=Boca Raton, FL | pages=6–232}}</ref>
|Dipole = 1.69 D<ref name=crc89>{{Cite book | editor-last=Lide | editor-first=David R. | name-list-style=vanc | title=CRC Handbook of Chemistry and Physics | url={{google books | plainurl=y | id=KACWPwAACAAJ}} | edition=89 | year=2008 | publisher=CRC Press | location=Boca Raton, FL | pages=9–55}}</ref>
|MagSus = −33.60·10<sup>−6</sup> cm<sup>3</sup>/mol
}}
| Section1       = {{Chembox Identifiers
|IUPHAR_ligand = 2299
|CASNo_Ref = {{cascite|correct|CAS}}
|CASNo = 64-17-5
|UNII_Ref = {{fdacite|correct|FDA}}
|UNII = 3K9958V90M
|SMILES = OCC
|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
|ChemSpiderID = 682
|DrugBank_Ref = {{drugbankcite|correct|drugbank}}
|DrugBank = DB00898
|KEGG = C00469
|PubChem = 702
|ChEBI = 16236
|ChEBI_Ref = {{ebicite|correct|EBI}}
|ChEMBL = 545
|ChEMBL_Ref = {{ebicite|correct|EBI}}
|Gmelin = 787
|Beilstein = 1718733
|StdInChI = 1S/C2H6O/c1-2-3/h3H,2H2,1H3
|StdInChI_Ref = {{stdinchicite|correct|chemspider}}
|InChI = 1/C2H6O/c1-2-3/h3H,2H2,1H3
|StdInChIKey = LFQSCWFLJHTTHZ-UHFFFAOYSA-N
|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
|InChIKey = LFQSCWFLJHTTHZ-UHFFFAOYAB
|3DMet = B01253
|UNNumber = UN 1170
}}
| Section7       = {{Chembox Hazards
|ExternalSDS = <ref name="sigmaaldrichMSDS">{{cite web | url=https://www.sigmaaldrich.com/CH/en/sds/sial/459836 | title=MSDS Ethanol | access-date=2023-01-12}}</ref>
|GHSPictograms = {{GHS02}} {{GHS07}}
|GHSSignalWord = Danger
|HPhrases = {{H-phrases|225|319|360D}}
|PPhrases = {{P-phrases|210|233|240|241|242|305+351+338}}
|NFPA-H = 2
|NFPA-F = 3
|NFPA-R = 0
|FlashPt = 14 °C (Absolute)<ref>{{Cite web | title=Ethanol | url=https://webwiser.nlm.nih.gov/substance?substanceId=18&identifier=Ethanol&identifierType=name&menuItemId=32&catId=58 | access-date=2021-06-25 | website=webwiser.nlm.nih.gov | language=en | archive-date=25 June 2021 | archive-url=https://web.archive.org/web/20210625194528/https://webwiser.nlm.nih.gov/substance?substanceId=18&identifier=Ethanol&identifierType=name&menuItemId=32&catId=58 }}</ref>
|LD50 = {{ubl|7060{{nbsp}}mg/kg (oral, rat)|3450{{nbsp}}mg/kg (mouse)}}<ref name="niosh">{{Cite web | title=Ethyl Alcohol | date=2 November 2018 | url=https://www.cdc.gov/niosh/idlh/64175.html | access-date=2023-12-23 | language=en}}</ref>
|PEL = TWA 1000 ppm (1900{{nbsp}}mg/m<sup>3</sup>)<ref name="niosh" />
|IDLH = 3300 ppm<ref name="niosh" />
|REL = TWA 1000 ppm (1900{{nbsp}}mg/m<sup>3</sup>)<ref name="niosh" />
}}
| Section9       = {{Chembox Related
|OtherCompounds = {{ubl|[[Ethane]]|[[Methanol]]}}
}}
}}

'''Ethanol''' (also called '''ethyl alcohol''', '''grain alcohol''', '''drinking alcohol''', or simply '''alcohol''') is an [[organic compound]] with the [[chemical formula]] {{chem2|CH3CH2OH}}. It is an [[Alcohol (chemistry)|alcohol]], with its formula also written as {{chem2|C2H5OH}}, {{chem2|C2H6O}} or EtOH, where Et is the [[pseudoelement symbol]] for [[ethyl group|ethyl]]. Ethanol is a [[Volatility (chemistry)|volatile]], [[flammable]], colorless liquid with a [[pungent]] taste.<ref>{{cite web | url=https://pubchem.ncbi.nlm.nih.gov/compound/Ethanol | title=Ethanol | series=PubChem | publisher=National Library of Medicine | access-date=28 September 2021}}</ref><ref>{{cite web | url=https://www.nj.gov/health/eoh/rtkweb/documents/fs/0844.pdf | title=Ethyl Alcohol | series=Hazardous Substance Fact Sheet | publisher=New Jersey Department of Health | access-date=28 September 2021}}</ref> As a [[psychoactive]] [[depressant]], it is the active ingredient in [[alcoholic beverage]]s, and the second most consumed drug globally behind [[caffeine]].<ref name="u385">{{cite journal | last1=Song | first1=Frank | last2=Walker | first2=Matthew P. | title=Sleep, alcohol, and caffeine in financial traders | journal=PLOS ONE | volume=18 | issue=11 | date=2023-11-08 | issn=1932-6203 | pmid=37939019 | pmc=10631622 | doi=10.1371/journal.pone.0291675 | doi-access=free | article-number=e0291675 | bibcode=2023PLoSO..1891675S}}</ref>

Ethanol is naturally produced by the [[fermentation]] process of [[sugar]]s by [[yeast]]s or via [[petrochemical]] processes such as [[ethylene]] hydration. Historically it was used as a [[general anesthetic]], and has modern medical applications as an [[antiseptic]], [[disinfectant]], solvent for some medications, and [[antidote]] for [[methanol poisoning]] and [[ethylene glycol poisoning]].<ref name="Powell1996">{{cite book | title=The Origins and Ancient History of Wine | series=Food and Nutrition in History and Anthropology | edition=1 | volume=11 | chapter=9: Wine and the vine in ancient Mesopotamia: the cuneiform evidence | pages=96–124 | author=Powell MA | veditors=McGovern PE, Fleming SJ, Katz SH | publisher=Taylor & Francis | location=Amsterdam | year=2004 | isbn=978-0-203-39283-6 | issn=0275-5769 | chapter-url=https://books.google.com/books?id=aXX2UcT_yw8C&q=Wine+and+the+vine+in+ancient+Mesopotamia:+the+cuneiform+evidence&pg=PA97 | access-date=2010-09-15}}</ref><ref name="Schnelle">{{cite journal | last=Schnelle | first=Norbert | date=August 1965 | title=Alcohol Given Intravenously for General Anesthesia | url=https://www.sciencedirect.com/science/article/abs/pii/S0039610916376502 | journal=Surgical Clinics of North America | volume=45 | issue=4 | pages=1041–1049 | doi=10.1016/S0039-6109(16)37650-2 | pmid=14312998 | access-date=December 30, 2022| url-access=subscription }}</ref> It is used as a chemical [[solvent]] and in the [[Chemical synthesis|synthesis]] of organic compounds, and as a [[Ethanol fuel|fuel source]] for lamps, stoves, and internal combustion engines. Ethanol also can be dehydrated to make ethylene, an important chemical feedstock. As of 2023, world production of ethanol fuel was {{convert|112.0|GL|usgal|abbr=off}}, coming mostly from the U.S. (51%) and Brazil (26%).<ref name="Renewable Fuels Association-2008">{{cite web | title=2008 World Fuel Ethanol Production | url=https://ethanolrfa.org/markets-and-statistics/annual-ethanol-production | access-date=21 June 2024 | publisher=Renewable Fuels Association | location=Ellisville, Missouri}}</ref>

The term "ethanol", originates from the [[ethyl group]] coined in 1834 and was officially adopted in 1892, while "alcohol"—now referring broadly to similar compounds—originally described a powdered [[Cosmetics|cosmetic]] and only later came to mean ethanol specifically.<ref>{{cite book |chapter= alcohol |title= The Oxford English Dictionary: Being a Corrected Re-Issue of with An Introduction, Supplement and Bibliography of a New English Dictionary on Historical Principles |volume= 1 A-B |year= 1913 |place= Oxford |publisher= Clarendon Press |url= https://archive.org/details/in.ernet.dli.2015.99992/page/n5/mode/2up?view=theater |page= [https://archive.org/details/in.ernet.dli.2015.99992/page/209/mode/2up?view=theater 209] |via= [[Internet Archive]] |access-date= 19 September 2025}}</ref>   Ethanol occurs naturally as a byproduct of [[yeast]] metabolism in environments like overripe fruit and palm blossoms, during plant [[germination]] under [[Anaerobic digestion|anaerobic]] conditions, in [[Outer space|interstellar space]], in human breath, and in rare cases, is produced internally due to [[auto-brewery syndrome]].

Ethanol has been used since ancient times as an [[Psychoactive drug|intoxicant]]. Production through [[fermentation]] and [[distillation]] evolved over centuries across various cultures. Chemical identification and synthetic production began by the 19th century.

== Name ==
''Ethanol'' is the [[systematic name]] [[IUPAC nomenclature of organic chemistry|defined]] by the [[International Union of Pure and Applied Chemistry]] for a compound consisting of an [[alkyl group]] with two carbon [[atom]]s (prefix "eth-"), having a single bond between them (infix "-an-") and an attached −OH [[functional group]] (suffix "-ol").<ref name="Pubchem">{{cite web | title=Ethanol – Compound Summary | url=https://pubchem.ncbi.nlm.nih.gov/compound/702 | website=The PubChem Project | location=Bethesda, MD | publisher=National Center for Biotechnology Information}}</ref>

The "eth-" prefix and the qualifier "ethyl" in "ethyl alcohol" originally came from the name "ethyl" assigned in 1834 to the group {{chem|C|2|H|5}}− by [[Justus von Liebig|Justus Liebig]]. He coined the word from the [[German language|German]] name ''Aether'' of the compound {{chem|C|2|H|5}}−O−{{chem|C|2|H|5}} (commonly called "ether" in [[English language|English]], more specifically called "[[diethyl ether]]").<ref>{{cite journal | last=Liebig | first=Justus | name-list-style=vanc | year=1834 | title=Ueber die Constitution des Aethers und seiner Verbindungen | trans-title=On the constitution of ether and its compounds | language=de | doi=10.1002/andp.18341072202 | journal=Annalen der Pharmacie | volume=9 | issue=22 | pages=1–39 | quote=From page 18: "''Bezeichnen wir die Kohlenwasserstoffverbindung 4C + 10H als das Radikal des Aethers mit E<sub>2</sub> und nennen es Ethyl'', ..." (Let us designate the hydrocarbon compound 4C + 10H as the radical of ether with E<sub>2</sub> and name it ethyl ...). | bibcode=1834AnP...107..337L | url=https://zenodo.org/record/1423568}}</ref> According to the ''[[Oxford English Dictionary]]'', ''Ethyl'' is a contraction of the Ancient Greek [[wikt:αἰθήρ#Ancient Greek|αἰθήρ]] (''{{transliteration|grc|aithḗr}}'', "upper air") and the Greek word [[wikt:ὕλη#Ancient Greek|ὕλη]] (''{{transliteration|grc|hýlē}}'', "wood, raw material", hence "matter, substance").<ref>{{OEtymD|ethyl}}</ref> ''Ethanol'' was coined as a result of a resolution on naming alcohols and phenols that was adopted at the International Conference on [[Chemical nomenclature|Chemical Nomenclature]] that was held in April 1892 in [[Geneva]], Switzerland.<ref>For a report on the 1892 International Conference on Chemical Nomenclature, see:
* {{cite journal | last=Armstrong | first=Henry | name-list-style=vanc | year=1892 | url={{google books | plainurl=y | id=LHkCAAAAIAAJ | page=56}} | title=The International Conference on Chemical Nomenclature | journal=Nature | volume=46 | pages=56–59 | doi=10.1038/046056c0 | issue=1177 | bibcode=1892Natur..46...56A | doi-access=free}}
* Armstrong's report is reprinted with the resolutions in English in: {{cite journal | last=Armstrong | first=Henry | name-list-style=vanc | year=1892 | url={{google books | plainurl=y | id=RogMAQAAIAAJ | page=398}} | title=The International Conference on Chemical Nomenclature | journal=The Journal of Analytical and Applied Chemistry | volume=6 | issue=1177 | pages=390–400 (398) | quote=The alcohols and the phenols will be called after the name of the hydrocarbon from which they are derived, terminated with the suffix ''ol'' (ex. pentanol, pentynol, etc.) | bibcode=1892Natur..46...56A | doi=10.1038/046056c0 | doi-access=free}}</ref>

The term ''alcohol'' now refers to a wider class of substances in chemistry nomenclature, but in common parlance it remains the name of ethanol. It is a medieval loan from [[Arabic]] {{nowrap|''[[Kohl (cosmetics)|al-kuḥl]]''}}, a powdered ore of [[antimony]] used since antiquity as a cosmetic, and retained that meaning in [[Middle Latin]].<ref>{{cite book | last=Multhauf | first=Robert P. | author-link=Robert P. Multhauf | year=1966 | title=The Origins of Chemistry | location=London | publisher=Oldbourne | isbn=978-2-88124-594-7}} p. 205; [[OED]]; [[etymonline.com]]</ref> The use of 'alcohol' for ethanol (in full, "alcohol of wine") was first recorded in 1753. Before the late 18th century the term ''alcohol'' generally referred to any sublimated substance.<ref>{{cite book | last1=Berthelot | first1=Marcellin | author1-link=Marcellin Berthelot | last2=Houdas | first2=Octave V. | year=1893 | title=La Chimie au Moyen Âge | volume=I | location=Paris | publisher=Imprimerie nationale | page=136}}</ref>

== Uses ==
=== Recreational drug ===
{{Main|Alcohol (drug)}}
As a [[central nervous system]] [[depressant]], ethanol is one of the most commonly consumed [[psychoactive drug]]s.<ref>{{Cite web | title=Alcohol use and safe drinking: MedlinePlus Medical Encyclopedia | url=https://medlineplus.gov/ency/article/001944.htm | access-date=2023-03-11 | website=medlineplus.gov | language=en}}</ref> Despite alcohol's psychoactive, addictive, and [[Alcohol and cancer|carcinogenic]] properties,<ref name=":0">{{Cite web |title=Alcohol |url=https://www.who.int/news-room/fact-sheets/detail/alcohol |access-date=2025-05-23 |website=www.who.int |language=en}}</ref> it is readily available and legal for sale in many countries. There are laws regulating the sale, exportation/importation, taxation, manufacturing, consumption, and possession of alcoholic beverages. The most common regulations are [[Alcohol tax|excise]], and prohibition for minors.

In mammals, ethanol is primarily [[metabolized]] in the [[liver]] and [[stomach]] by ADH enzymes.<ref name="Farrés">{{cite journal | vauthors=Farrés J, Moreno A, Crosas B, Peralba JM, Allali-Hassani A, Hjelmqvist L, Jörnvall H, Parés X | display-authors=6 | title=Alcohol dehydrogenase of class IV (σσ-ADH) from human stomach. cDNA sequence and structure/function relationships | journal=European Journal of Biochemistry | volume=224 | issue=2 | pages=549–557 | date=September 1994 | pmid=7925371 | doi=10.1111/j.1432-1033.1994.00549.x | doi-access=free}}</ref> These enzymes catalyze the [[oxidation]] of ethanol into [[acetaldehyde]] (ethanal):<ref>{{cite journal | vauthors=Edenberg HJ, McClintick JN | title=Alcohol Dehydrogenases, Aldehyde Dehydrogenases, and Alcohol Use Disorders: A Critical Review | journal=Alcoholism: Clinical and Experimental Research | volume=42 | issue=12 | pages=2281–2297 | date=December 2018 | pmid=30320893 | doi=10.1111/acer.13904 | pmc=6286250}}</ref>

:CH<sub>3</sub>CH<sub>2</sub>OH + NAD<sup>+</sup> → CH<sub>3</sub>CHO + [[NADH]] + H<sup>+</sup>

When present in significant concentrations, this metabolism of ethanol is additionally aided by the [[cytochrome P450]] enzyme [[CYP2E1]] in humans, while trace amounts are also metabolized by [[catalase]].<ref>{{cite book | author1=Heit, C. | author2=Dong, H. | author3=Chen, Y. | author4=Thompson, D.C. | author5=Dietrich, R.A. | author6=Vasiliou, V.K. | title=Cytochrome P450 2E1: Its Role in Disease and Drug Metabolism | chapter=The Role of CYP2E1 in Alcohol Metabolism and Sensitivity in the Central Nervous System | series=Subcellular Biochemistry | date=2013 | volume=67 | pages=235–237 | doi=10.1007/978-94-007-5881-0_8 | pmid=23400924 | pmc=4314297 | isbn=978-94-007-5880-3}}</ref> The resulting intermediate, acetaldehyde, is a known carcinogen, and poses significantly greater toxicity in humans than ethanol itself. Many of the symptoms typically associated with alcohol intoxication—as well as many of the health hazards typically associated with the long-term consumption of ethanol—can be attributed to acetaldehyde toxicity in humans.<ref>{{cite web | title=Alcohol Metabolism: An Update | url=https://pubs.niaaa.nih.gov/publications/aa72/aa72.htm | website=NIAA Publications | publisher=National Institute of Health | access-date=10 March 2021 | archive-date=28 February 2021 | archive-url=https://web.archive.org/web/20210228215303/https://pubs.niaaa.nih.gov/publications/AA72/AA72.htm }}</ref>

The subsequent oxidation of acetaldehyde into [[acetate]] is performed by [[aldehyde dehydrogenase]] (ALDH) enzymes. A mutation in the ALDH2 gene that encodes for an inactive or dysfunctional form of this enzyme affects roughly 50% of east Asian populations, contributing to the characteristic [[alcohol flush reaction]] that can cause temporary reddening of the skin as well as a number of related, and often unpleasant, symptoms of acetaldehyde toxicity.<ref name="Eng et al.">{{cite journal | vauthors=Eng MY, Luczak SE, Wall TL | date=2007 | title=ALDH2, ADH1B, and ADH1C genotypes in Asians: a literature review | journal=Alcohol Research & Health | volume=30 | issue=1 | pages=22–27 | pmc=3860439 | pmid=17718397}}</ref> This mutation is typically accompanied by another mutation in the ADH enzyme [[ADH1B]] in roughly 80% of east Asians, which improves the catalytic efficiency of converting ethanol into acetaldehyde.<ref name="Eng et al." />

=== Medical ===
{{Main|Alcohol (medicine)}}
Ethanol is the oldest known [[sedative]], used as an oral [[general anesthetic]] during surgery in ancient [[Mesopotamia]] and in [[Middle Ages|medieval times]].<ref name="Powell1996" /><ref name="Schnelle" /> Mild intoxication starts at a [[blood alcohol concentration]] of {{nowrap|0.03{{tsp}}–{{tsp}}}}0.05% and induces [[Induced coma|anesthetic coma]] at 0.4%.<ref>{{cite web | url=https://www.medicalsecretsmd.com/post/natural-old-school-anesthesia-ancient-opium-alcohol-marijuana | title=3 Natural, Ancient Anesthetics No One Talks About: Opium, Alcohol, Marijuana | last=Kaveh | first=Anthony | website=Dr. Anthony Kaveh, MD | access-date=December 30, 2022}}</ref> This use carries the high risk of deadly [[alcohol intoxication]], [[pulmonary aspiration]] and vomiting, which led to use of alternatives in antiquity, such as [[opium]] and [[cannabis]], and later diethyl ether, starting in the 1840s.<ref name= Grattan>Grattan, N. "Treatment of Uterine Haemorrhage". ''Provincial Medicine and Surgical Journal''. Vol. 1, No. 6 (Nov. 7, 1840), p. 107.</ref>

Ethanol is used as an [[antiseptic]] in medical wipes and [[hand sanitizer]] gels  for its bactericidal and anti-fungal effects.<ref>{{cite journal | last1=Pohorecky | first1=Larissa A. | last2=Brick | first2=John | title=Pharmacology of ethanol | journal=Pharmacology & Therapeutics | date=January 1988 | volume=36 | issue=2–3 | pages=335–427 | doi=10.1016/0163-7258(88)90109-X | pmid=3279433}}</ref> Ethanol kills [[microorganism]]s by dissolving their membrane [[lipid bilayer]] and [[Denaturation (biochemistry)|denaturing]] their [[protein]]s, and is effective against most [[bacteria]], [[fungi]] and [[virus]]es. It is ineffective against bacterial [[Endospore|spores]], which can be treated with [[hydrogen peroxide]].<ref>{{cite journal | vauthors=McDonnell G, Russell AD | title=Antiseptics and disinfectants: activity, action, and resistance | journal=Clinical Microbiology Reviews | volume=12 | issue=1 | pages=147–179 | date=January 1999 | pmid=9880479 | pmc=88911 | doi=10.1128/CMR.12.1.147}}</ref>

A solution of 70% ethanol is more effective than pure ethanol because ethanol relies on water molecules for optimal antimicrobial activity. Absolute ethanol may inactivate microbes without destroying them because the alcohol is unable to fully permeate the microbe's membrane.<ref>{{Cite web | url=https://www.cdc.gov/infectioncontrol/guidelines/disinfection/disinfection-methods/chemical.html | title=Chemical Disinfectants {{!}} Disinfection & Sterilization Guidelines {{!}} Guidelines Library {{!}} Infection Control {{!}} CDC | website=www.cdc.gov | language=en-us | access-date=2018-01-29}}</ref><ref>{{Cite web | url=https://www.researchgate.net/post/Why_is_70_ethanol_used_for_wiping_microbiological_working_areas | title=Why is 70% ethanol used for wiping microbiological working areas? | website=ResearchGate | language=en | access-date=2018-01-29}}</ref> Ethanol can also be used as a disinfectant and antiseptic by inducing cell dehydration through disruption of the osmotic balance across the cell membrane, causing  water to leave the cell, leading to cell death.<ref>{{cite web | title=Ethanol | url=https://www.drugbank.ca/drugs/DB00898 | website=www.drugbank.ca | access-date=28 January 2019}}</ref>

Ethanol may be administered as an [[antidote]] to [[ethylene glycol poisoning]]<ref>{{cite journal | last1=Scalley | first1=Robert | name-list-style=vanc | title=Treatment of Ethylene Glycol Poisoning | journal=American Family Physician | date=September 2002 | volume=66 | issue=5 | pages=807–813 | pmid=12322772 | url=https://www.aafp.org/afp/2002/0901/p807.html | access-date=15 January 2018}}</ref> and [[methanol poisoning]].<ref name=EM2016>{{cite journal | last1=Beauchamp | first1=GA | last2=Valento | first2=M | title=Toxic Alcohol Ingestion: Prompt Recognition And Management In The Emergency Department. | journal=Emergency Medicine Practice | date=September 2016 | volume=18 | issue=9 | pages=1–20 | pmid=27538060}}</ref> It does so by acting as a [[competitive inhibitor]] against [[methanol]] and [[ethylene glycol]] for [[alcohol dehydrogenase]] (ADH).<ref>{{Cite journal | last1=Sasanami | first1=Misa | last2=Yamada | first2=Taihei | last3=Obara | first3=Takafumi | last4=Nakao | first4=Atsunori | last5=Naito | first5=Hiromichi | title=Oral Ethanol Treatment for Ethylene Glycol Intoxication | journal=Cureus | year=2020 | volume=12 | issue=12 | article-number=e12268 | doi=10.7759/cureus.12268 | doi-access=free | issn=2168-8184 | pmc=7827791 | pmid=33510981}}</ref> Though it has more side effects, ethanol is less expensive and more readily available than [[fomepizole]] in the role.<ref>{{Cite journal | last1=Anseeuw | first1=Kurt | last2=Sabbe | first2=Marc B. | last3=Legrand | first3=Annemie | date=April 2008 | title=Methanol poisoning: the duality between 'fast and cheap' and 'slow and expensive' | journal=European Journal of Emergency Medicine | volume=15 | issue=2 | pages=107–109 | doi=10.1097/MEJ.0b013e3282f3c13b | issn=0969-9546 | pmid=18446077 | s2cid=23861841}}</ref>

Ethanol is used to dissolve many water-insoluble medications and related compounds. Liquid preparations of [[analgesics|pain medications]], [[Cold medicine|cough and cold medicines]], and mouth washes, for example, may contain up to 25% ethanol<ref>{{Cite web | url=https://www.mssny.org/App_Themes/MSSNY/pdf/AlcoholContent.pdf | title=Alcohol Content in Common Preparations | publisher=Medical Society of the State of New York | access-date=October 8, 2019 | archive-date=29 April 2021 | archive-url=https://web.archive.org/web/20210429232655/https://www.mssny.org/App_Themes/MSSNY/pdf/AlcoholContent.pdf }}</ref> and may need to be avoided in individuals with adverse reactions to ethanol such as [[alcohol-induced respiratory reactions]].<ref name="Ann Allergy Asthma Immunol 2013">{{cite journal | vauthors=Adams KE, Rans TS | title=Adverse reactions to alcohol and alcoholic beverages | journal=Annals of Allergy, Asthma & Immunology | volume=111 | issue=6 | pages=439–445 | date=December 2013 | pmid=24267355 | doi=10.1016/j.anai.2013.09.016}}</ref> Ethanol is present mainly as an antimicrobial preservative in over 700 liquid preparations of medicine including [[acetaminophen]], [[iron supplement]]s, [[ranitidine]], [[furosemide]], [[mannitol]], [[phenobarbital]], [[trimethoprim/sulfamethoxazole]] and [[over-the-counter]] [[cough medicine]].<ref>{{cite journal | vauthors=Zuccotti GV, Fabiano V | title=Safety issues with ethanol as an excipient in drugs intended for pediatric use | journal=Expert Opinion on Drug Safety | volume=10 | issue=4 | pages=499–502 | date=July 2011 | pmid=21417862 | doi=10.1517/14740338.2011.565328 | s2cid=41876817}}</ref>

Some medicinal solutions of ethanol are also known as [[tincture]]s.

=== Energy source ===
{{See also|Food vs. fuel}}
{{Main|Ethanol fuel}}
[[File:Corn vs Ethanol production.webp|thumb|upright=1.36|right|Corn vs ethanol production in the United States
{{legend|#FFD932|Total corn production ([[bushel]]s) (left)}}
{{legend|B51700|Corn used for [[Ethanol fuel]] (bushels) (left)}}
{{legend-line|#313131 solid 3px|Percent of corn used for Ethanol (right)}}
]]

The largest single use of ethanol is as an engine [[fuel]] and [[fuel additive]]. [[Brazil]] in particular relies heavily upon the use of ethanol as an engine fuel, due in part to its role as one of the world's leading producers of ethanol.<ref>{{cite web | title=Availability of Sources of E85 | url=http://www.cleanairtrust.org/Sources-Availability-E85.html | website=Clean Air Trust | access-date=27 July 2015}}</ref><ref>{{cite web | title=Fuel ethanol production worldwide | url=https://www.statista.com/statistics/281606/ethanol-production-in-selected-countries/ | website=Statista | access-date=2 June 2021}}</ref> [[Gasoline]] sold in Brazil contains at least 25% [[anhydrous]] ethanol. Hydrous ethanol (about 95% ethanol and 5% water) can be used as fuel in more than 90% of new gasoline-fueled cars sold in the country.

The US and many other countries primarily use E10 (10% ethanol, sometimes known as gasohol) and E85 (85% ethanol) ethanol/gasoline mixtures. Over time, it is believed that a material portion of the ≈{{convert|150|e9USgal|m3|adj=on}} per year market for gasoline will begin to be replaced with fuel ethanol.<ref name="rfa1">{{cite web | date=20 November 2006 | title=First Commercial U.S. Cellulosic Ethanol Biorefinery Announced | url=http://www.ethanolmarket.com/PressReleaseRFA102006.html | access-date=31 May 2011 | publisher=Renewable Fuels Association}}</ref>

[[File:Ethyl alcohol usp grade.jpg|thumb|upright|[[chemical purity|USP grade]] ethanol for laboratory use]]

Australian law limits the use of pure ethanol from [[sugarcane]] waste to 10% in automobiles. Older cars (and vintage cars designed to use a slower burning fuel) should have the engine valves upgraded or replaced.<ref>{{cite web | url=http://www.mtfca.com.au | title=Model T Ford Club Australia (Inc.) | last=Green | first=Ray | name-list-style=vanc | access-date=24 June 2011 | archive-url=https://web.archive.org/web/20140114075515/http://mtfca.com.au/ | archive-date=14 January 2014 }}</ref>

According to an industry [[advocacy group]], ethanol as a fuel reduces harmful [[tailpipe emissions]] of carbon monoxide, particulate matter, [[oxides of nitrogen]], and other ozone-forming pollutants.<ref>{{cite web | url=http://www.ethanol.org/index.php?id=34&parentid=8#Environment | title=Ethanol 101 | publisher=American Coalition for Ethanol | access-date=26 March 2011 | archive-date=14 November 2020 | archive-url=https://web.archive.org/web/20201114003907/https://ethanol.org/index.php?id=34&parentid=8#Environment }}</ref> [[Argonne National Laboratory]] analyzed greenhouse gas emissions of many different engine and fuel combinations, and found that [[biodiesel]]/petrodiesel blend ([[B20 (biodiesel)|B20]]) showed a reduction of 8%, conventional [[E85]] ethanol blend a reduction of 17% and [[cellulosic ethanol]] 64%, compared with pure gasoline.<ref>{{cite book | chapter-url=http://www.energyfuturecoalition.org/biofuels/benefits_env_public_health.htm | chapter=The Biofuels FAQs | archive-url=https://web.archive.org/web/20110219052041/http://www.energyfuturecoalition.org/biofuels/benefits_env_public_health.htm | archive-date=19 February 2011 | title=The Biofuels Source Book | author=Energy Future Coalition | publisher=[[United Nations Foundation]]}}</ref> Ethanol has a much greater research octane number (RON) than gasoline, meaning it is less prone to pre-ignition, allowing for better ignition advance which means more torque, and efficiency in addition to the lower carbon emissions.<ref>{{Cite journal | last1=Malaquias | first1=Augusto César Teixeira | last2=Netto | first2=Nilton Antonio Diniz | last3=Filho | first3=Fernando Antonio Rodrigues | last4=da Costa | first4=Roberto Berlini Rodrigues | last5=Langeani | first5=Marcos | last6=Baêta | first6=José Guilherme Coelho | date=2019-11-18 | title=The misleading total replacement of internal combustion engines by electric motors and a study of the Brazilian ethanol importance for the sustainable future of mobility: a review | journal=Journal of the Brazilian Society of Mechanical Sciences and Engineering | language=en | volume=41 | issue=12 | page=567 | doi=10.1007/s40430-019-2076-1 | issn=1806-3691 | doi-access=free}}</ref>

Ethanol [[combustion]] in an [[internal combustion engine]] yields many of the products of incomplete combustion produced by gasoline and significantly larger amounts of [[formaldehyde]] and related species such as acetaldehyde.<ref>{{cite web | url=https://www.arb.ca.gov/bluebook/bb10/hea/hea-39037_05.htm | author=California Air Resources Board | title=Definition of a Low Emission Motor Vehicle in Compliance with the Mandates of Health and Safety Code Section 39037.05, second release | date=October 1989 | access-date=18 February 2018 | archive-url=https://web.archive.org/web/20180218150535/https://www.arb.ca.gov/bluebook/bb10/hea/hea-39037_05.htm | archive-date=18 February 2018 }}</ref> This leads to a significantly larger photochemical reactivity and more [[ground level ozone]].<ref>{{cite book | vauthors=Lowi A, Carter WP | date=March 1990 | title=A Method for Evaluating the Atmospheric Ozone Impact of Actual Vehicle emissions |publisher=S.A.E. Technical Paper <!--put as publisher because work= gets ignored and have no idea what to put this as--> | location=Warrendale, Pennsylvania}}</ref> This data has been assembled into The Clean Fuels Report comparison of fuel emissions<ref>{{cite web | vauthors=Jones TT | year=2008 | url=http://www.researchandmarkets.com/reports/598475 | title=The Clean Fuels Report: A Quantitative Comparison Of Motor (engine) Fuels, Related Pollution and Technologies | archive-url=https://archive.today/20120909174028/http://www.researchandmarkets.com/reports/598475 | archive-date=9 September 2012 | website=researchandmarkets.com}}</ref> and show that ethanol exhaust generates 2.14&nbsp;times as much ozone as gasoline exhaust.<ref>{{cite book | url={{google books | plainurl=y | id=Qg1qDQAAQBAJ | page=60}} | title=Electro-rheological Fluids and Magneto-rheological Suspensions | via=Proceedings of the 12th International Conference | location=Philadelphia | date=16–20 August 2010 | last=Tao | first=Rongjia | name-list-style=vanc | publisher=World Scientific | isbn=978-981-4340-22-9}}</ref> When this is added into the custom ''Localized Pollution Index'' of The Clean Fuels Report, the local pollution of ethanol (pollution that contributes to smog) is rated 1.7, where gasoline is 1.0 and higher numbers signify greater pollution.<ref>{{Cite news | url=https://www.scientificamerican.com/article/reduce-air-pollution-do-not-rely-on-ethanol/ | title=Want to Reduce Air Pollution? Don't Rely on Ethanol Necessarily | last=Biello | first=David | name-list-style=vanc | work=Scientific American | access-date=11 July 2017 | language=en}}</ref> The [[California Air Resources Board]] formalized this issue in 2008 by recognizing control standards for formaldehydes as an emissions control group, much like the conventional [[NOx]] and reactive organic gases (ROGs).<ref>{{cite web | title=Adoption of the Airborne Toxic Control Measure to Reduce Formaldehyde Emissions from Composite Wood Products | url=http://www.wdma.com/TechnicalCenter/GreenZone/CARB/tabid/111/Default.aspx | archive-url=https://web.archive.org/web/20100309071022/http://www.wdma.com/TechnicalCenter/GreenZone/CARB/tabid/111/Default.aspx | archive-date=9 March 2010 | date=30 July 2008 | location=Chicago & Washington, DC | publisher=Window and Door Manufacturers Association}}</ref>

More than 20% of Brazilian cars are able to use 100% ethanol as fuel, which includes ethanol-only engines and [[flex-fuel]] engines.<ref>{{cite web | url=http://economia.estadao.com.br/noticias/geral,tecnologia-flex-em-automoveis-atrai-estrangeiros,178105 | title=Tecnologia flex atrai estrangeiros | publisher=Agência Estado | language=pt-BR}}</ref> Flex-fuel engines in Brazil are able to work with all ethanol, all gasoline or any mixture of both. In the United States, flex-fuel vehicles can run on 0% to 85% ethanol (15% gasoline) since higher ethanol blends are not yet allowed or efficient. Brazil supports this fleet of ethanol-burning automobiles with large national infrastructure that produces ethanol from domestically grown sugarcane.

Ethanol's high [[miscibility]] with water makes it unsuitable for shipping through modern [[Pipeline transport|pipelines]] like liquid hydrocarbons.<ref name="HornKrupp2009">{{Cite book | first1=Miriam | last1=Horn | first2=Fred | last2=Krupp | name-list-style=vanc | title=Earth: The Sequel: The Race to Reinvent Energy and Stop Global Warming | journal=Physics Today | volume=62 | issue=4 | pages=63–65 | url={{google books | plainurl=y | id=vjs7GtArBNoC | lage=85}} | date=16 March 2009 | isbn=978-0-393-06810-8 | bibcode=2009PhT....62d..63K | doi=10.1063/1.3120901 | s2cid=153892198}}</ref> Mechanics have seen increased cases of damage to small engines (in particular, the [[carburetor]]) and attribute the damage to the increased water retention by ethanol in fuel.<ref><!-- http://www.msnbc.msn.com/id/25936782/ -->[http://www.nbcnews.com/id/25936782/ "Mechanics see ethanol damaging small engines"]{{Webarchive|url=https://web.archive.org/web/20200923224041/http://www.nbcnews.com/id/25936782/ |date=23 September 2020 }}, ''NBC News'', 8 January 2008</ref>

Ethanol was commonly used as fuel in early [[bipropellant]] [[rocket]] (liquid-propelled) vehicles, in conjunction with an [[oxidizer]] such as liquid oxygen. The German A-4 ballistic rocket of [[World War&nbsp;II]] (better known by its propaganda name {{Nowrap|[[V-2]]}}),<ref name="Ignition">{{Cite book | last=Clark | first=John. D. | author-link=John Drury Clark | url=https://archive.org/details/ignitioninformal0000clar | title=Ignition! an informal history of liquid rocket propellants | others=Foreword by Isaac Asimov | date=1972 | publisher=Rutgers University Press | isbn=978-0-8135-0725-5 | page=[https://archive.org/details/ignitioninformal0000clar/page/9 9] | url-access=registration}}</ref> which is credited as having begun the space age, used ethanol as the main constituent of {{nowrap|''[[B-Stoff]]''}}. Under such nomenclature, the ethanol was mixed with 25% water to reduce the combustion chamber temperature.<ref>{{cite web | url=http://daviddarling.info/encyclopedia/V/V-2.html | title=The Internet Encyclopedia of Science: V-2 | last=Darling | first=David | name-list-style=vanc | access-date=27 July 2024}}</ref><ref name="braeunig">{{Cite web | title=Basics of Space Flight: Rocket Propellants | url=http://braeunig.us/space/propel.htm | access-date=11 March 2023 | website=braeunig.us}}</ref> The {{Nowrap|V-2's}} design team helped develop U.S. rockets following World War&nbsp;II, including the ethanol-fueled [[Redstone (rocket family)|Redstone rocket]], which launched the first U.S. astronaut on [[suborbital spaceflight]].<ref>{{cite web | title=A Brief History of Rocketry | url=http://science.ksc.nasa.gov/history/rocket-history.txt | work=NASA Historical Archive | archive-url=https://web.archive.org/web/20060805203537/http://science.ksc.nasa.gov/history/rocket-history.txt | archive-date=5 August 2006 }}</ref><ref>{{Cite book | last1=Kuettner | first1=Joachim P. | author-link=Joachim Kuettner | url=https://ntrs.nasa.gov/citations/19630012071 | title=Mercury Project Summary Including Results of the Fourth Manned Orbital Flight: May 15 and 16, 1963 | last2=Bertram | first2=Emil | date=October 1963 | page=70 | chapter=Mercury-Redstone Launch-Vehicle development and performance | id=NASA-SP-45 | chapter-url=https://ntrs.nasa.gov/api/citations/19630012071/downloads/19630012071.pdf#page=78 | via=[[NASA Technical Reports Server|NTRS]]}}</ref> Alcohols fell into general disuse as more energy-dense rocket fuels were developed,<ref name="braeunig" /> although ethanol was used in recent experimental [[Light aircraft|lightweight]] [[Mark-III X-racer|rocket-powered racing aircraft]].<ref name="sdc20100426">{{cite web | url=http://www.space.com/businesstechnology/rocket-racing-tulsa-demonstration-100426.html | title=Rocket Racing League Unveils New Flying Hot Rod | first=Denise | last=Chow | name-list-style=vanc | website=[[Space.com]] | date=26 April 2010 | access-date=27 July 2024 | archive-url=https://web.archive.org/web/20140308035740/https://www.space.com/8290-rocket-racing-league-unveils-flying-hot-rod.html | archive-date=8 March 2014 | url-status=live}}</ref>

Commercial fuel cells operate on reformed natural gas, [[hydrogen]] or methanol. Ethanol is an attractive alternative due to its wide availability, low cost, high purity and low toxicity. There is a wide range of fuel cell concepts that have entered trials including [[direct-ethanol fuel cell]]s, auto-thermal reforming systems and thermally integrated systems. The majority of work is being conducted at a research level although there are a number of organizations at the beginning of the commercialization of ethanol fuel cells.<ref>{{cite journal | vauthors=Badwal SP, Giddey S, Kulkarni A, Goel J, Basu S | title=Direct ethanol fuel cells for transport and stationary applications – A comprehensive review | journal=Applied Energy | date=May 2015 | volume=145 | pages=80–103 | doi=10.1016/j.apenergy.2015.02.002 | doi-access=free | bibcode=2015ApEn..145...80B}}</ref>

Ethanol fireplaces can be used for home heating or for decoration. Ethanol can also be used as stove fuel for cooking.<ref>{{cite news | title=Can Ethanol Fireplaces Be Cozy? | first=Debra Jo | last=Immergut | date=3 December 2015 | url=https://www.wsj.com/articles/one-fire-please-hold-the-soot-1449170833 | access-date=2 March 2016 | work=The Wall Street Journal}}</ref><ref>{{cite journal | vauthors=Rajvanshi AK, Patil SM, Mendonca B | title=Low-concentration ethanol stove for rural areas in India | journal=Energy for Sustainable Development | volume=11 | issue=1 | date=March 2007 | pages=94–99 | doi=10.1016/S0973-0826(08)60568-2 | bibcode=2007ESusD..11...94R | url=https://www.sciencedirect.com/science/article/pii/S0973082608605682 | citeseerx=10.1.1.142.5846}}</ref>

{| class="wikitable"
|+[[Energy density|Energy content]] ([[lower heating value]]) of some fuels compared with ethanol
|-
!Fuel type|| MJ/L|| MJ/kg|| [[octane rating|Research<br />octane<br />number]]
|-
|[[Wood fuel|Dry wood (20% moisture)]]|| ||~19.5||
|-
|[[Methanol]]||17.9||19.9||108.7<ref name="Fuel 89 (2010) 2713-2720">{{cite journal | doi=10.1016/j.fuel.2010.01.032 | title=Impact of alcohol–gasoline fuel blends on the performance and combustion characteristics of an SI engine | year=2010 | last1=Eyidogan | first1=Muharrem | last2=Ozsezen | first2=Ahmet Necati | last3=Canakci | first3=Mustafa | last4=Turkcan | first4=Ali | name-list-style=vanc | journal=Fuel | volume=89 | issue=10 | pages=2713–2720 | bibcode=2010Fuel...89.2713E}}</ref>
|-
|[[Ethanol fuel|Ethanol]]||21.2<ref name="Thomas">{{cite web | last=Thomas | first=George | url=http://www.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf | title=Overview of Storage Development DOE Hydrogen Program | archive-url=https://web.archive.org/web/20070221185632/http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf | archive-date=21 February 2007 | location=Livermore, California | publisher=Sandia National Laboratories | year=2000}}</ref>||26.8<ref name="Thomas" />
||108.6<ref name="Fuel 89 (2010) 2713-2720" />
|-
|[[E85]]<br />(85% ethanol, 15% gasoline)||25.2||33.2||105
|-
|[[Liquefied natural gas]]||25.3||~55||
|-
|[[Autogas]] ([[Liquified petroleum gas|LPG]])<br />(60% [[propane]] + 40% [[butane]])||26.8||50||
|-
|[[Aviation gasoline]]<br />(high-octane gasoline, not jet fuel)||33.5||46.8||100/130 (lean/rich)
|-
|[[Alcohol fuel|Gasohol]]<br />(90% gasoline + 10% ethanol)||33.7||47.1||93/94
|-
| Regular gasoline/petrol||34.8||44.4<ref>{{cite news | url=http://www1.eere.energy.gov/hydrogenandfuelcells/pdfs/storage.pdf | last=Thomas | first=George | name-list-style=vanc | title=Overview of Storage Development DOE Hydrogen Program | publisher=Sandia National Laboratories | year=2000 | access-date=1 August 2009}}</ref>||min. 91
|-
| Premium gasoline/petrol|| || ||max. 104
|-
|[[Diesel fuel|Diesel]]||38.6||45.4||25
|-
|[[Charcoal]], extruded||50||23||
|}

===Other uses===
{{more citations needed section|date=November 2024}}
Ethanol is an important industrial ingredient. It has widespread use as a precursor for other organic compounds such as ethyl [[halide]]s, ethyl [[ester]]s, diethyl ether, acetic acid, and ethyl [[amine]]s.  It is considered a universal [[solvent]], as its [[molecular]] structure allows for the dissolving of both [[Chemical polarity#Polar molecules|polar]], [[hydrophilic]] and [[nonpolar]], [[hydrophobic]] compounds. As ethanol also has a low [[boiling point]], it is easy to remove from a solution that has been used to dissolve other compounds, making it a popular extracting agent for botanical oils. [[Cannabis oil]] extraction methods often use ethanol as an extraction solvent,<ref>{{Cite web | url=https://www.cannabisbusinesstimes.com/article/your-guide-to-ethanol-extraction/ | title=Your Guide to Ethanol Extraction | website=Cannabis Business Times | language=en | access-date=2019-04-09}}</ref> and also as a post-processing solvent to remove oils, waxes, and [[chlorophyll]] from solution in a process known as [[Winterization of oil|winterization]].

Ethanol is found in [[paint]]s, tinctures, markers, personal care products such as mouthwashes, perfumes and deodorants, and [[Zoological specimens#Wet specimens|wet specimen]] preservatives. [[Polysaccharides]] [[Ethanol precipitation|precipitate]] from aqueous solution in the presence of alcohol, and ethanol precipitation is used for this reason in the purification of [[DNA]] and [[RNA]]. Because of its low [[freezing point]] of {{cvt|-114|C|F}} and low toxicity, ethanol is sometimes used in laboratories (with [[dry ice]] or other coolants) as a [[cooling bath]] to keep vessels at temperatures below the freezing point of water. For the same reason, it is also used as the active fluid in [[alcohol thermometer]]s.

== Chemistry ==
{{more citations needed section|date=November 2024}}
{{Further|Ethanol (data page)}}

Ethanol is a 2-carbon [[Alcohol (chemistry)|alcohol]]. Its [[molecular formula]] is {{chem2|CH3CH2OH}}. The structure of the molecule of ethanol is {{chem2|CH3\sCH2\sOH}} (an [[ethyl group]] linked to a [[hydroxyl group]]), which indicates that the carbon of a [[methyl group]] ({{chem2|\sCH3}}) is attached to the carbon of a [[methylene group]] ({{chem2|\sCH2\s}}), which is attached to the oxygen of a hydroxyl group ({{chem2|\sOH}}). It is a constitutional [[isomer]] of [[dimethyl ether]]. Ethanol is sometimes abbreviated as '''EtOH''', using the common organic chemistry notation of representing the ethyl group ({{chem2|\sCH2CH3}}) with '''Et'''.

=== Physical properties ===
[[File:Spiritusflamme mit spektrum.png|thumb|upright|Ethanol burning with its spectrum depicted]]

Ethanol is a volatile, colorless liquid that has a slight odor. It burns with a smokeless blue flame that is not always visible in normal light. The physical properties of ethanol stem primarily from the presence of its hydroxyl group and the shortness of its carbon chain. Ethanol's hydroxyl group is able to participate in hydrogen bonding, rendering it more viscous and less volatile than less polar organic compounds of similar molecular weight, such as [[propane]].{{citation needed|date=November 2024}} Ethanol's [[adiabatic flame temperature]] for combustion in air is 2082&nbsp;°C or 3779&nbsp;°F.<ref name="chemss">{{cite news | url=http://www.che.msstate.edu/pdfs/fuel_cell_curriculum/me_mods/ME_Combustion_And_Air_Pollution_Module_1.doc | title=Flame Temperature Analysis and NOx Emissions for Different Fuels | publisher=Mississippi State Department of Chemical Engineering}}</ref>

Ethanol is slightly more refractive than water, having a [[refractive index]] of 1.36242 (at λ=589.3&nbsp;nm and {{convert|18.35|C|F|disp=or}}).<ref name="crc" /> The [[triple point]] for ethanol is {{nowrap|150 ± 20 [[Kelvin|K]]}}.<ref>{{Cite web | date=2023 | title=Ethanol | url=https://webbook.nist.gov/cgi/inchi/InChI%3D1S/C2H6O/c1-2-3/h3H%2C2H2%2C1H3 | access-date=2023-12-23 | website=NIST Chemistry WebBook, SRD 69}}</ref>

=== Solvent properties ===
Ethanol is a versatile solvent, [[miscible]] with water and with many organic solvents, including [[acetic acid]], [[acetone]], [[benzene]], [[carbon tetrachloride]], [[chloroform]], diethyl ether, ethylene glycol, [[glycerol]], [[nitromethane]], [[pyridine]], and [[toluene]]. Its main use as a solvent is in making tincture of iodine, cough syrups, etc.<ref name="crc" /><ref name="merck" /> It is also miscible with light aliphatic hydrocarbons, such as [[pentane]] and [[hexane]], and with aliphatic chlorides such as [[1,1,1-Trichloroethane|trichloroethane]] and [[tetrachloroethylene]].<ref name="merck">{{cite book | last=Windholz | first=Martha | name-list-style=vanc | title=The Merck index: an encyclopedia of chemicals and drugs | publisher=Merck | location=Rahway, NJ | year=1976 | isbn=978-0-911910-26-1 | edition=9th}}{{page needed|date=February 2014}}</ref>

Ethanol's miscibility with water contrasts with the immiscibility of longer-chain alcohols (five or more carbon atoms), whose water miscibility decreases sharply as the number of carbons increases.<ref name="m_and_b">{{cite book | last1=Morrison | first1=Robert Thornton | last2=Boyd | first2=Robert Neilson | name-list-style=vanc | title=Organic Chemistry | url=https://archive.org/details/organicchemistry00morrrich | url-access=registration | edition=2nd | year=1972 | publisher=Allyn and Bacon, inc. | isbn=978-0-205-08452-4}}{{page needed|date=February 2014}}</ref> The miscibility of ethanol with [[alkane]]s is limited to alkanes up to [[undecane]]: mixtures with [[dodecane]] and higher alkanes show a [[miscibility gap]] below a certain temperature (about 13&nbsp;°C for dodecane<ref>{{cite journal | vauthors=Dahlmann U, Schneider GM | title=(Liquid + liquid) phase equilibria and critical curves of (ethanol + dodecane or tetradecane or hexadecane or 2,2,4,4,6,8,8-heptamethylnonane) from 0.1 MPa to 120.0 MPa | journal=J Chem Thermodyn | volume=21 | pages=997–1004 | year=1989 | doi=10.1016/0021-9614(89)90160-2 | issue=9 | bibcode=1989JChTh..21..997D}}</ref>). The miscibility gap tends to get wider with higher alkanes, and the temperature for complete miscibility increases.

Ethanol-water mixtures have less volume than the sum of their individual components at the given fractions. Mixing equal volumes of ethanol and water results in only 1.92 volumes of mixture.<ref name="crc">{{cite book | editor-last=Lide | editor-first=D. R. | name-list-style=vanc | title=CRC Handbook of Chemistry and Physics 81st edition | publisher=CRC press | year=2000 | isbn=978-0-8493-0481-1}}</ref>{{sfn|Lodgsdon|1991|p=813}} Mixing ethanol and water is [[exothermic]], with up to 777&nbsp;J/mol<ref>{{cite journal | vauthors=Costigan MJ, Hodges LJ, Marsh KN, Stokes RH, Tuxford CW | title=The Isothermal Displacement Calorimeter: Design Modifications for Measuring Exothermic Enthalpies of Mixing | journal=Aust. J. Chem. | volume=33 | issue=10 | page=2103 | year=1980 | doi=10.1071/CH9802103 | bibcode=1982AuJCh..35.1971I}}</ref> being released at 298&nbsp;K.

[[File:Ethanol-xtal-1976-3D-balls.png|thumb|Hydrogen bonding in solid ethanol at −186&nbsp;°C]]

Hydrogen bonding causes pure ethanol to be [[hygroscopic]] to the extent that it readily absorbs water from the air. The polar nature of the hydroxyl group causes ethanol to dissolve many ionic compounds, notably [[sodium hydroxide|sodium]] and [[potassium hydroxide]]s, [[magnesium chloride]], [[calcium chloride]], [[ammonium chloride]], [[ammonium bromide]], and [[sodium bromide]].<ref name="merck" /> [[Sodium chloride|Sodium]] and [[potassium chloride]]s are slightly soluble in ethanol.<ref name="merck" /> Because the ethanol molecule also has a nonpolar end, it will also dissolve nonpolar substances, including most [[essential oil]]s<ref name="merckoils">''Merck Index of Chemicals and Drugs'', 9th ed.; monographs 6575 through 6669</ref> and numerous flavoring, coloring, and medicinal agents.

The addition of even a few percent of ethanol to water sharply reduces the [[surface tension]] of water. This property partially explains the "[[tears of wine]]" phenomenon. When wine is swirled in a glass, ethanol evaporates quickly from the thin film of wine on the wall of the glass. As the wine's ethanol content decreases, its surface tension increases and the thin film "beads up" and runs down the glass in channels rather than as a smooth sheet.

=== Azeotrope with water ===
At atmospheric pressure, mixtures of ethanol and water form an [[azeotrope]] at about 89.4&nbsp;[[mol%]] ethanol (95.6% ethanol by mass,<ref name=NIST-SR1828>{{Cite web | last=National Institute of Standards and Technology | title=Standard Reference Material 1828: Ethanol-Water Solutions | url=https://tsapps.nist.gov/srmext/certificates/archives/1828.pdf}}</ref> 97% [[alcohol by volume]]), with a boiling point of {{Convert|351.3|K}}.<ref name=PembertonMash>{{cite journal | vauthors=Pemberton RC, Mash CJ | title=Thermodynamic properties of aqueous non-electrolyte mixtures II. Vapour pressures and excess Gibbs energies for water + ethanol at 303.15 to 363.15 K determined by an accurate static method | journal=J Chem Thermodyn | volume=10 | pages=867–888 | year=1978 | doi=10.1016/0021-9614(78)90160-X | issue=9 | bibcode=1978JChTh..10..867P}}</ref> At lower pressure, the composition of the ethanol-water azeotrope shifts to more ethanol-rich mixtures.<ref name="Beebe1942">{{cite journal | last1=Beebe | first1=A. H. | last2=Coulter | first2=K. E. | last3=Lindsay | first3=R. A. | last4=Baker | first4=E. M. | title=Equilibria in Ethanol-Water System at Pressures Less Than Atmospheric | journal=Industrial & Engineering Chemistry | date=December 1942 | volume=34 | issue=12 | pages=1501–1504 | doi=10.1021/ie50396a019}}</ref> The minimum-pressure azeotrope has an ethanol fraction of 100%<ref name="Beebe1942"/> and a boiling point of {{Convert|306|K}},<ref name=PembertonMash/> corresponding to a pressure of roughly 70&nbsp;[[torr]] (9.333&nbsp;kPa).<ref name=PressureSwingDistillation>{{Cite web | title=6.4 Pressure swing distillation {{!}} Hyper-TVT: on line Thermische VerfahrensTechnik | work=Institute of Process Engineering {{!}} ETH Zurich | date=10 November 2003 | access-date=12 October 2024 | url=https://www.hyper-tvt.ethz.ch/distillation-azeotrope-pressure_swing.html | language=en}}</ref> Below this pressure, there is no azeotrope, and it is possible to distill absolute ethanol from an ethanol-water mixture.<ref name=PressureSwingDistillation/>

=== Flammability ===
An ethanol–water solution will catch fire if heated above a temperature called its [[flash point]] and an ignition source is then applied to it.<ref name="flash point">{{cite web | url=http://www.nttworldwide.com/tech2212.htm | title=Flash Point and Fire Point | website=Nttworldwide.com | archive-url=https://web.archive.org/web/20101214222420/http://www.nttworldwide.com/tech2212.htm | archive-date=14 December 2010 }}</ref> For 20% alcohol by mass (about 25% by volume), this will occur at about {{convert|25|°C|°F}}. The flash point of pure ethanol is {{convert|13|°C|°F}},<ref name="NFPA 325">{{cite book | title=NFPA 325: Guide to Fire Hazard Properties of Flammable Liquids, Gases, and Volatile Solids | date=1 January 1994 | publisher=National Fire Protection Association (NFPA) | location=Quincy, Massachusetts | url=https://standards.globalspec.com/std/638448/NFPA%20325}}</ref> but may be influenced very slightly by atmospheric composition such as pressure and humidity. Ethanol mixtures can ignite below average room temperature. Ethanol is considered a flammable liquid (Class 3 Hazardous Material) in concentrations above 2.35% by mass (3.0% by volume; 6 [[Alcohol proof|proof]]).<ref name="49 CFR 173.120">{{cite web | title=49 CFR §&nbsp;173.120 – Class 3 – Definitions. | publisher=Legal Information Institute | url=https://www.law.cornell.edu/cfr/text/49/173.120 | quote=a flammable liquid (Class 3) means a liquid having a flash point of not more than 60 °C (140 °F)}}</ref><ref name="Martínez et al" /><ref name="49 CFR 172.101">{{cite web | title=49 CFR §&nbsp;172.101 – Purpose and use of hazardous materials table. | publisher=Legal Information Institute, Cornell University | url=https://www.law.cornell.edu/cfr/text/49/172.101 | quote=Hazardous materials descriptions and proper shipping names: Ethanol or Ethyl alcohol or Ethanol solutions or Ethyl alcohol solutions; Hazard class or Division: 3; Identification Numbers: UN1170; PG: II; Label Codes: 3;}}</ref> Dishes using burning alcohol for culinary effects are called [[flambé]].
<!-- Mass % and volume % (ABV) are not the same. You must convert weight percent to volume percent to compare the values in the table below to common beer and wine values (which are labeled ABV, or "alcohol by volume"). For example, 5 wt% ethanol in water is approximately 6.3 vol% ethanol in water. -->

{| class="wikitable mw-collapsible mw-collapsed" style="white-space: nowrap; text-align: center;"
|+ Flash points of ethanol–water mixtures<ref name="Ha et al">{{cite journal | last1=Ha | first1=Dong-Myeong | last2=Park | first2=Sang Hun | last3=Lee | first3=Sungjin | title=The Measurement of Flash Point of Water-Methanol and Water-Ethanol Systems Using Seta Flash Closed Cup Tester | journal=Fire Science and Engineering | date=April 2015 | volume=29 | issue=2 | pages=39–43 | doi=10.7731/KIFSE.2015.29.2.039 | url=https://www.researchgate.net/publication/277973979 | quote=Page 4, Table 3}}</ref><ref name="Martínez et al">{{cite journal | last1=Martínez | first1=P. J. | last2=Rus | first2=E. | last3=Compaña | first3=J. M. | title=Flash Point Determination of Binary Mixtures of Alcohols, Ketones and Water | journal=Departamento de Ingeniería Química, Facultad de Ciencias | url=https://engage.aiche.org/HigherLogic/System/DownloadDocumentFile.ashx?DocumentFileKey=e53a8ccc-48b1-4e3b-b59f-bb579cc5132b&ssopc=1 | at=p. 3, Table 4}}</ref><ref name="eng">{{cite web | url=http://www.engineeringtoolbox.com/ethanol-water-d_989.html | title=Flash points of ethanol-based water solutions | access-date=23 June 2011 | website=Engineeringtoolbox.com}}</ref>
! rowspan="2" | Ethanol<br /> [[mole fraction]], %
! colspan="2" | Temperature
|-
! °C
! °F
|-
| 1 || {{convert|84.5|°C|°F|disp=table}}<ref name="Martínez et al" />
|-
| 2 || {{convert|64|°C|°F|disp=table}}<ref name="Martínez et al" />
|-
| 2.35 || {{convert|60|°C|°F|disp=table}}<ref name="Martínez et al" /><ref name="49 CFR 173.120" />
|-
| 3 || {{convert|51.5|°C|°F|disp=table}}<ref name="Martínez et al" />
|-
| 5 || {{convert|43|°C|°F|disp=table}}<ref name="Ha et al" />
|-
| 6 || {{convert|39.5|°C|°F|disp=table}}<ref name="Martínez et al" />
|-
| 10 || {{convert|31|°C|°F|disp=table}}<ref name="Ha et al" />
|-
| 20 || {{convert|25|°C|°F|disp=table}}<ref name="Martínez et al" />
|-
| 30 || {{convert|24|°C|°F|disp=table}}<ref name="Ha et al" />
|-
| 50 || {{convert|20|°C|°F|disp=table}}<ref name="Ha et al" /><ref name="Martínez et al" />
|-
| 70 || {{convert|16|°C|°F|disp=table}}<ref name="Ha et al" />
|-
| 80 || {{convert|15.8|°C|°F|disp=table}}<ref name="Martínez et al" />
|-
| 90 || {{convert|14|°C|°F|disp=table}}<ref name="Ha et al" />
|-
| 100 || {{convert|12.5|°C|°F|disp=table}}<ref name="Ha et al" /><ref name="Martínez et al" /><ref name="NFPA 325" />
|}

== Natural occurrence ==
Ethanol is a byproduct of the metabolic process of yeast. As such, ethanol will be present in any yeast habitat. Ethanol can commonly be found in overripe fruit.<ref>{{cite journal | vauthors=Dudley R | title=Ethanol, fruit ripening, and the historical origins of human alcoholism in primate frugivory | journal=Integrative and Comparative Biology | volume=44 | issue=4 | pages=315–323 | date=August 2004 | pmid=21676715 | doi=10.1093/icb/44.4.315 | doi-access=free}}</ref> Ethanol produced by symbiotic yeast can be found in [[palm wine|bertam palm]] blossoms. Although some animal species, such as the [[pentailed treeshrew]], exhibit ethanol-seeking behaviors, most show no interest or avoidance of food sources containing ethanol.<ref>{{cite web | title=Fact or Fiction?: Animals Like to Get Drunk | last=Graber | first=Cynthia | name-list-style=vanc | year=2008 | url=http://www.scientificamerican.com/article.cfm?id=animals-like-to-get-drunk | website=Scientific American | access-date=23 July 2010}}</ref> Ethanol is also produced during the germination of many plants as a result of natural [[anaerobiosis]].<ref>{{cite journal | doi=10.1007/BF02922229 | last1=Leblová | first1=Sylva | last2=Sinecká | first2=Eva | last3=Vaníčková | first3=Věra | name-list-style=vanc | title=Pyruvate metabolism in germinating seeds during natural anaerobiosis | year=1974 | journal=Biologia Plantarum | volume=16 | issue=6 | pages=406–411 | bibcode=1974BioPl..16..406L | s2cid=34605254}}</ref>

Ethanol has been detected in [[outer space]], forming an icy coating around dust grains in [[interstellar cloud]]s.<ref>{{cite journal | doi=10.1016/j.chemphys.2007.02.018 | title=One possible origin of ethanol in interstellar medium: Photochemistry of mixed CO<sub>2</sub>–C<sub>2</sub>H<sub>6</sub> films at 11 K. A FTIR study | vauthors=Schriver A, Schriver-Mazzuoli L, Ehrenfreund P, d'Hendecourt L | journal=Chemical Physics | volume=334 | issue=1–3 | year=2007 | pages=128–137 | bibcode=2007CP....334..128S}}</ref>
Minute quantity amounts (average 196 [[parts per billion|ppb]]) of endogenous ethanol and acetaldehyde were found in the exhaled breath of healthy volunteers.<ref>{{cite journal | vauthors=Turner C, Spanel P, Smith D | title=A longitudinal study of ethanol and acetaldehyde in the exhaled breath of healthy volunteers using selected-ion flow-tube mass spectrometry | journal=Rapid Communications in Mass Spectrometry | volume=20 | issue=1 | pages=61–68 | year=2006 | pmid=16312013 | doi=10.1002/rcm.2275 | bibcode=2006RCMS...20...61T}}</ref> [[Auto-brewery syndrome]], also known as gut fermentation syndrome, is a rare medical condition in which intoxicating quantities of ethanol are produced through [[endogenous]] [[fermentation]] within the [[digestive system]].<ref>{{cite web | url=https://www.npr.org/blogs/thesalt/2013/09/17/223345977/auto-brewery-syndrome-apparently-you-can-make-beer-in-your-gut | title=Auto-Brewery Syndrome: Apparently, You Can Make Beer In Your Gut | first=Michaeleen | last=Doucleff | name-list-style=vanc | publisher=NPR | date=17 September 2013}}</ref>

== Production ==
[[File:Ethanol Flasche.jpg|thumb|upright|94% denatured ethanol sold in a bottle for household use]]

Ethanol is produced both as a [[petrochemical]], through the hydration of [[ethylene]] and, via biological processes, by fermenting [[sugar]]s with [[yeast]].<ref name="Mills-Ecklund">{{cite journal | vauthors=Mills GA, Ecklund EE | title=Alcohols as Components of Transportation Fuels | journal=[[Annual Review of Energy]] | volume=12 | pages=47–80 | year=1987 | doi=10.1146/annurev.eg.12.110187.000403 | doi-access=free}}</ref> Which process is more economical depends on prevailing prices of [[petroleum]] and grain feed stocks.

=== Sources ===
World production of ethanol in 2006 was {{convert|51|GL|usgal}}, with 69% of the world supply coming from Brazil and the U.S.<ref name="Renewable Fuels Association-2008" /> Brazilian ethanol is produced from sugarcane, which has relatively high yields (830% more fuel than the fossil fuels used to produce it) compared to some other [[energy crop]]s.<ref name="WaPo-Brazil">{{cite news | date=19 August 2006 | title=Brazil's Road to Energy Independence | newspaper=[[The Washington Post]] | url=https://www.washingtonpost.com/wp-dyn/content/article/2006/08/19/AR2006081900842.html | vauthors=Reel M}}</ref> Sugarcane not only has a greater concentration of sucrose than corn (by about 30%), but is also much easier to extract. The [[bagasse]] generated by the process is not discarded, but burned by power plants to produce electricity. Bagasse burning accounts for around 9% of the electricity produced in Brazil.<ref>{{Cite journal | last1=Rossi | first1=Liane M. | last2=Gallo | first2=Jean Marcel R. | last3=Mattoso | first3=Luiz H. C. | last4=Buckeridge | first4=Marcos S. | last5=Licence | first5=Peter | last6=Allen | first6=David T. | date=2021-03-29 | title=Ethanol from Sugarcane and the Brazilian Biomass-Based Energy and Chemicals Sector | journal=ACS Sustainable Chemistry & Engineering | language=en | volume=9 | issue=12 | pages=4293–4295 | doi=10.1021/acssuschemeng.1c01678 | s2cid=233676614 | issn=2168-0485 | doi-access=free}}</ref>

In the 1970s most industrial ethanol in the U.S. was made as a petrochemical, but in the 1980s the U.S. introduced subsidies for [[corn-based ethanol]].<ref name="WittcoffReuben2004">{{cite book | last1=Wittcoff | first1=Harold A. | url={{google books | plainurl=y | id=4KHzc-nYPNsC | page=136}} | title=Industrial Organic Chemicals | last2=Reuben | first2=Bryan G. | last3=Plotkin | first3=Jeffery S. | publisher=John Wiley & Sons | year=2004 | isbn=978-0-471-44385-8 | pages=136– | name-list-style=vanc}}</ref> According to the Renewable Fuels Association, as of 30 October 2007, 131 grain ethanol bio-refineries in the U.S. have the capacity to produce {{convert|7|e9USgal|m3}} of ethanol per year. An additional 72 construction projects underway (in the U.S.) can add {{convert|6.4|e9USgal|m3}} of new capacity in the next 18 months.<ref name="rfa1" />

In India ethanol is made from sugarcane.<ref>{{Cite book | last=Swami | first=V. N. | publisher=Vidyabharti Publication | year=2020 | location=[[Latur]], Maharashtra, India | page=119 | language=mr | script-title=mr:विद्याभराती जिल्हा मध्यवर्ती सहकारी बँक भारती परीक्षा मार्गदर्शक | trans-title=Vidyabharti District Co-operative Bank recruitment examination guide (Bank clerk grade examination)}}</ref> [[Sweet sorghum]] is another potential source of ethanol, and is suitable for growing in dryland conditions. The [[International Crops Research Institute for the Semi-Arid Tropics]] is investigating the possibility of growing sorghum as a source of fuel, food, and animal feed in arid parts of [[Asia]] and [[Africa]].<ref>{{Cite web | title=Sweet sorghum for food, feed and fuel | date=January 2008 | website=New Agriculturalist | url=http://resourcespace.icrisat.ac.in/filestore/8/4/0_6c06c9b61b19c20/840_be710da94740b90.pdf | access-date=2023-03-11 | archive-url=https://web.archive.org/web/20150904014010/http://resourcespace.icrisat.ac.in/filestore/8/4/0_6c06c9b61b19c20/840_be710da94740b90.pdf | archive-date=4 September 2015}}</ref> Sweet sorghum has one-third the water requirement of sugarcane over the same time period. It also requires about 22% less water than corn. The world's first sweet sorghum ethanol distillery began commercial production in 2007 in [[Andhra Pradesh]], [[India]].<ref>[http://exploreit.icrisat.org/sites/default/files/uploads/1378281395_DevelopingASweetSorghum_2013.pdf "Developing a sweet sorghum ethanol value chain"] {{Webarchive|url=https://web.archive.org/web/20140223044045/http://exploreit.icrisat.org/sites/default/files/uploads/1378281395_DevelopingASweetSorghum_2013.pdf |date=23 February 2014 }}. [[ICRISAT]], 2013</ref>

Ethanol has been produced in the laboratory by converting [[carbon dioxide]] via biological and [[electrochemical]] reactions.<ref>{{cite journal | vauthors=Liew F, Henstra AM, Köpke M, Winzer K, Simpson SD, Minton NP | title=Metabolic engineering of Clostridium autoethanogenum for selective alcohol production | journal=Metabolic Engineering | volume=40 | pages=104–114 | date=March 2017 | pmid=28111249 | doi=10.1016/j.ymben.2017.01.007 | pmc=5367853}}</ref><ref>{{Cite news | url=https://newscenter.lbl.gov/2017/09/18/solar-fuel-system-recycles-co2-for-ethanol-ethylene/ | title=Solar-to-Fuel System Recycles CO2 for Ethanol and Ethylene | date=18 September 2017 | work=News Center | access-date=19 September 2017 | language=en-US}}</ref>

{{block indent|CO<sub>2</sub> + {{chem|H|2|O}} → {{chem|CH|3|C|H|2|O}}H + side products}}

=== Hydration ===
Ethanol can be produced from petrochemical feed stocks, primarily by the [[acid]]-[[catalysis|catalyzed]] [[Hydration reaction|hydration]] of ethylene. It is often referred to as synthetic ethanol.

:{{chem2| C2H4 + H2O -> C2H5OH }}

The catalyst is most commonly [[phosphoric acid]],<ref name="r_and_c">{{cite book | last1=Roberts | first1=John D. | last2=Caserio | first2=Marjorie C. | name-list-style=vanc | author-link1=John D. Roberts | author-link2=Marjorie Constance Caserio | year=1977 | publisher=W. A. Benjamin | title=Basic Principles of Organic Chemistry | isbn=978-0-8053-8329-4 | url=https://archive.org/details/basicprincipleso1977obe}}{{page needed|date=February 2014}}</ref><ref name="ullmann" /> [[adsorption|adsorbed]] onto a porous support such as [[silica gel]] or [[diatomaceous earth]]. This catalyst was first used for large-scale ethanol production by the [[Shell Oil Company]] in 1947.<ref name="ECT4 820">{{cite encyclopedia | chapter=Ethanol | title=Encyclopedia of chemical technology | year=1991 | page=82 | volume=9}}</ref> The reaction is carried out in the presence of high pressure steam at {{convert|300|C|F}} where a 5:3 ethylene to steam ratio is maintained.<ref>[http://www.essentialchemicalindustry.org/chemicals/ethanol.html "Ethanol"] {{Webarchive|url=https://web.archive.org/web/20150113175914/http://www.essentialchemicalindustry.org/chemicals/ethanol.html |date=13 January 2015 }}. ''Essential Chemical Industry''.</ref><ref>{{cite web | last=Harrison | first=Tim | date=May 2014 | url=http://www.chemlabs.bris.ac.uk/outreach/resources/Catalysis%20Web%20Pages%20for%20PreUniversity%20students%20V1_0.pdf | title=Catalysis Web Pages for Pre-University Students V1_0 | archive-url=https://web.archive.org/web/20210305074612/http://www.chemlabs.bris.ac.uk/outreach/resources/Catalysis%20Web%20Pages%20for%20PreUniversity%20students%20V1_0.pdf | archive-date=5 March 2021 | website=Bristol ChemLabs, School of Chemistry | publisher=University of Bristol}}</ref> This process was used on an industrial scale by [[Union Carbide]] Corporation and others. It is no longer practiced in the US as fermentation ethanol produced from corn is more economical.<ref>{{Cite web | last=Tullo | first=Alexander | date=2021-08-26 | title=Last synthetic ethanol plant in US to close | url=https://cen.acs.org/energy/biofuels/Last-synthetic-ethanol-plant-US/99/i31 | access-date=2022-11-22 | website=cen.acs.org}}</ref>

In an older process, first practiced on the industrial scale in 1930 by Union Carbide<ref name="ECT4 817">{{cite book | last=Lodgsdon | first=John E. | chapter=Ethanol | editor1-last=Howe-Grant | editor1-first=Mary | editor2-last=Kirk | editor2-first=Raymond E. | editor3-last=Othmer | editor3-first=Donald F. | editor4-last=Kroschwitz | editor4-first=Jacqueline I. | title=Encyclopedia of chemical technology | publisher=Wiley | location=New York | year=1991 | isbn=978-0-471-52669-8 | edition=4th | volume=9 | page=817}} Republished as {{cite book | last=Lodgsdon | first=John E. | chapter=Ethanol | date=4 December 2000 | editor-last=Seidel | editor-first=Arza | title=Kirk-Othmer Encyclopedia of Chemical Technology | edition=5th | publisher=Wiley | isbn=978-0-471-48494-3 | doi=10.1002/0471238961.0520080112150719.a01}}</ref> but now almost entirely obsolete, ethylene was hydrated indirectly by reacting it with concentrated [[sulfuric acid]] to produce [[ethyl sulfate]], which was [[hydrolyzed]] to yield ethanol and regenerate the sulfuric acid:<ref name="s_and_h" />

:{{chem2| C2H4 + H2SO4 -> C2H5HSO4 }}
:{{chem2| C2H5HSO4 + H2O -> H2SO4 + C2H5OH }}

=== Fermentation ===
{{more citations needed section|date=November 2024}}
{{Main|Ethanol fermentation|Cellulosic ethanol}}
{{See also|Yeast in winemaking}}
Ethanol in [[alcoholic beverage]]s and fuel is produced by fermentation. Certain species of yeast (e.g., ''[[Saccharomyces cerevisiae]]'') metabolize sugar (namely [[polysaccharide]]s), producing ethanol and carbon dioxide. The chemical equations below summarize the conversion:

{{block indent|[[glucose|{{chem|C|6|H|12|O|6}}]] → 2 {{chem|CH|3|C|H|2|O}}H + 2 CO<sub>2</sub>}}
{{block indent|[[sucrose|{{chem|C|12|H|22|O|11}}]] + {{chem|H|2|O}} → 4 {{chem|CH|3|C|H|2|O}}H + 4 CO<sub>2</sub>}}

Fermentation is the process of culturing yeast under favorable thermal conditions to produce alcohol. This process is carried out at around {{convert|35|-|40|C|F}}. Toxicity of ethanol to yeast limits the ethanol concentration obtainable by brewing; higher concentrations, therefore, are obtained by [[Fortified wine|fortification]] or [[distillation]]. The most ethanol-tolerant yeast strains can survive up to approximately 18% ethanol by volume.

To produce ethanol from starchy materials such as [[cereal]]s, the [[starch]] must first be converted into sugars. In brewing [[beer]], this has traditionally been accomplished by allowing the grain to germinate, or [[malt]], which produces the [[enzyme]] [[amylase]]. When the malted grain is [[mashing|mashed]], the amylase converts the remaining starches into sugars.

Sugars for [[ethanol fermentation]] can be obtained from [[cellulose]]. Deployment of this technology could turn a number of cellulose-containing agricultural by-products, such as [[corncob]]s, [[straw]], and [[sawdust]], into renewable energy resources. Other agricultural residues such as sugarcane bagasse and energy crops such as [[switchgrass]] may also be fermentable sugar sources.<ref>{{cite web | last=Clines | first=Tom | name-list-style=vanc | title=Brew Better Ethanol | publisher=Popular Science Online | date=July 2006 | url=http://www.popsci.com/popsci/energy/6756226d360ab010vgnvcm1000004eecbccdrcrd.html | archive-url=https://web.archive.org/web/20071103083747/http://www.popsci.com/popsci/energy/6756226d360ab010vgnvcm1000004eecbccdrcrd.html | archive-date=3 November 2007}}</ref>

=== Testing ===
[[File:EthanolMIRInfraredSpectra.PNG|class=skin-invert-image|thumb|upright=1.35|Infrared reflection spectra of liquid ethanol, showing the −OH band centered near 3300&nbsp;cm<sup>−1</sup> and C−H bands near 2950&nbsp;cm<sup>−1</sup>]]
[[File:Ethanol near IR spectrum.png|class=skin-invert-image|thumb|upright=1.35|[[Near-infrared spectrum]] of liquid ethanol]]

Breweries and [[biofuel]] plants employ two methods for measuring ethanol concentration. Infrared ethanol sensors measure the vibrational frequency of dissolved ethanol using the C−H band at 2900&nbsp;cm{{sup|−1}}. This method uses a relatively inexpensive solid-state sensor that compares the C−H band with a reference band to calculate the ethanol content. The calculation makes use of the [[Beer–Lambert law]]. Alternatively, by measuring the density of the starting material and the density of the product, using a [[hydrometer]], the change in specific gravity during fermentation indicates the alcohol content. This inexpensive and indirect method has a long history in the beer brewing industry.

== Purification ==
Ethylene hydration or brewing produces an ethanol–water mixture. For most industrial and fuel uses, the ethanol must be purified. [[Fractional distillation]] at atmospheric pressure can concentrate ethanol to 95.6% by weight (89.5 mole%). This mixture is an azeotrope with a boiling point of {{convert|78.1|C|F}}, and ''cannot'' be further purified by distillation. Addition of an entraining agent, such as benzene, [[cyclohexane]], or [[heptane]], allows a new ternary azeotrope comprising the ethanol, water, and the entraining agent to be formed. This lower-boiling ternary azeotrope is removed preferentially, leading to water-free ethanol.<ref name="ullmann">{{cite book | first1=Naim | last1=Kosaric | first2=Zdravko | last2=Duvnjak | first3=Adalbert | last3=Farkas | first4=Hermann | last4=Sahm | first5=Stephanie | last5=Bringer-Meyer | first6=Otto | last6=Goebel | first7=Dieter | last7=Mayer | name-list-style=vanc | chapter=Ethanol | title=Ullmann's Encyclopedia of Industrial Chemistry | pages=1–72 | year=2011 | publisher=Wiley-VCH | location=Weinheim | doi=10.1002/14356007.a09_587.pub2 | isbn=978-3-527-30673-2}}{{subscription required}}</ref>

Apart from distillation, ethanol may be dried by addition of a [[desiccant]], such as [[molecular sieves]], cellulose, or [[cornmeal]]. The desiccants can be dried and reused.<ref name="ullmann" /> [[Molecular sieve]]s can be used to selectively absorb the water from the 95.6% ethanol solution.<ref>{{Cite book | url={{google books | plainurl=y | id=4iEhAQAAMAAJ}} | title=Advances in Cereal Science and Technology | last=Chemists | first=American Association of Cereal | date=1986 | publisher=American Association of Cereal Chemists, Incorporated | isbn=978-0-913250-45-7 | language=en}}</ref> Molecular sieves of pore-size 3&nbsp;[[Angstrom|Å]], a type of [[zeolite]], effectively sequester water molecules while excluding ethanol molecules. Heating the wet sieves drives out the water, allowing regeneration of their desiccant capability.<ref>{{citation | url=https://www.bio.umass.edu/microscopy/mol_sieves.htm | title=Molecular Sieve Information | author=Dale Callaham}}</ref>

Membranes can also be used to separate ethanol and water. Membrane-based separations are not subject to the limitations of the water-ethanol azeotrope because the separations are not based on vapor-liquid equilibria. Membranes are often used in the so-called hybrid membrane distillation process. This process uses a pre-concentration distillation column as the first separating step. The further separation is then accomplished with a membrane operated either in vapor permeation or pervaporation mode. Vapor permeation uses a vapor membrane feed and pervaporation uses a liquid membrane feed.

A variety of other techniques have been discussed, including the following:<ref name="ullmann" />
* Salting using [[potassium carbonate]] to exploit its insolubility will cause a phase separation with ethanol and water. This offers a very small potassium carbonate impurity to the alcohol that can be removed by distillation. This method is very useful in purification of ethanol by distillation, as ethanol forms an [[azeotrope]] with water.
* Direct [[electrochemical reduction of carbon dioxide]] to ethanol under ambient conditions using [[copper nanoparticle]]s on a carbon nanospike film as the catalyst;<ref>{{cite journal | last1=Song | first1=Yang | last2=Peng | first2=Rui | last3=Hensley | first3=Dale K. | last4=Bonnesen | first4=Peter V. | last5=Liang | first5=Liangbo | last6=Wu | first6=Zili | last7=Meyer | first7=Harry M. | last8=Chi | first8=Miaofang | last9=Ma | first9=Cheng | last10=Sumpter | first10=Bobby G. | last11=Rondinone | first11=Adam J. | name-list-style=vanc | date=2016 | title=High-Selectivity Electrochemical Conversion of CO2 to Ethanol using a Copper Nanoparticle/N-Doped Graphene Electrode | journal=[[ChemistrySelect]] | issue=Preprint | doi=10.1002/slct.201601169 | volume=1 | pages=6055–6061 | doi-access=free}}</ref>
* Extraction of ethanol from grain mash by [[supercritical carbon dioxide]];
* [[Pervaporation]];
* [[Fractional freezing]] is also used to concentrate fermented alcoholic solutions, such as traditionally made [[Applejack (beverage)]];
* [[Pressure swing adsorption]].<ref>{{cite journal | doi=10.1016/j.renene.2011.09.027 | title=Production of anhydrous ethanol using various PSA (Pressure Swing Adsorption) processes in pilot plant | year=2012 | last1=Jeong | first1=Jun-Seong | last2=Jeon | first2=Hyungjin | last3=Ko | first3=Kyung-mo | last4=Chung | first4=Bongwoo | last5=Choi | first5=Gi-Wook | name-list-style=vanc | journal=Renewable Energy | volume=42 | pages=41–45 | bibcode=2012REne...42...41J}}</ref>

=== Grades of ethanol ===
{{Further|Denatured alcohol}}
Pure ethanol and alcoholic beverages are heavily [[Sin tax|taxed]] as psychoactive drugs, but ethanol has many uses that do not involve its consumption. To relieve the tax burden on these uses, most jurisdictions waive the tax when an agent has been added to the ethanol to render it unfit to drink. These include [[bitterant|bittering agents]] such as [[denatonium benzoate]] and toxins such as methanol, [[naphtha]], and pyridine. Products of this kind are called ''denatured alcohol.''<ref>{{cite web | url=http://www.procurement.umich.edu/Contracts/Denatured_Alchohol.pdf | title=U-M Program to Reduce the Consumption of Tax-free Alcohol; Denatured Alcohol a Safer, Less Expensive Alternative | publisher=University of Michigan | access-date=29 September 2007 | archive-url=https://web.archive.org/web/20071127095510/http://www.procurement.umich.edu/Contracts/Denatured_Alchohol.pdf | archive-date=27 November 2007 }}</ref><ref>Great Britain (2005). ''[http://www.opsi.gov.uk/si/si2005/20051524.htm The Denatured Alcohol Regulations 2005] {{Webarchive|url=https://web.archive.org/web/20091209162605/http://www.opsi.gov.uk/si/si2005/20051524.htm |date=9 December 2009 }}.'' Statutory Instrument 2005 No. 1524.</ref>

Absolute or anhydrous alcohol refers to ethanol with a low water content. There are various grades with maximum water contents ranging from 1% to a few parts per million (ppm). If [[azeotropic distillation]] is used to remove water, it will contain trace amounts of the material separation agent (e.g. benzene).<ref>{{cite book | first1=Raj K. | last1=Bansal | last2=Bernthsen | first2=August | name-list-style=vanc | title=A Textbook of Organic Chemistry | url={{google books | plainurl=y | id=1B6ijcTkD5EC | page=402}} | year=2003 | publisher=New Age International Limited | isbn=978-81-224-1459-2 | pages=402–}}</ref> Absolute alcohol is not intended for human consumption. Absolute ethanol is used as a solvent for laboratory and industrial applications, where water will react with other chemicals, and as fuel alcohol. Spectroscopic ethanol is an absolute ethanol with a low absorbance in [[ultraviolet]] and visible light, fit for use as a solvent in [[ultraviolet-visible spectroscopy]].<ref>{{cite book | last1=Christian | first1=Gary D. | name-list-style=vanc | chapter=Solvents for Spectrometry | title=Analytical chemistry | date=2004 | publisher=John Wiley & Sons | location=Hoboken, NJ | isbn=978-0-471-21472-4 | edition=6th | volume=1 | page=[https://archive.org/details/analyticalchemis00chri_0/page/473 473] | chapter-url=https://archive.org/details/analyticalchemis00chri_0/page/473}}</ref> Pure ethanol is classed as 200 [[proof (alcohol)|proof]] in the US, equivalent to 175 degrees proof in the UK system.<ref name="Andrews2007">{{cite book | first=Sudhir | last=Andrews | name-list-style=vanc | title=Textbook Of Food & Bevrge Mgmt | url={{google books | plainurl=y | id=HfHtaq1GWUcC& | page=268}} | date=1 August 2007 | publisher=Tata McGraw-Hill Education | isbn=978-0-07-065573-7 | pages=268–}}</ref> Rectified spirit, an azeotropic composition of 96% ethanol containing 4% water, is used instead of anhydrous ethanol for various purposes. Spirits of wine are about 94% ethanol (188 proof). The impurities are different from those in 95% (190 proof) laboratory ethanol.<ref>{{cite journal | vauthors=Kunkee RE, Amerine MA | title=Sugar and alcohol stabilization of yeast in sweet wine | journal=Applied Microbiology | volume=16 | issue=7 | pages=1067–1075 | date=July 1968 | doi=10.1128/AEM.16.7.1067-1075.1968 | pmid=5664123 | pmc=547590}}</ref>

== Reactions ==
{{more citations needed section|date=November 2024}}
{{Further|Alcohol (chemistry)}}

Ethanol is classified as a primary alcohol, meaning that the carbon that its hydroxyl group attaches to has at least two hydrogen atoms attached to it as well. Many ethanol reactions occur at its hydroxyl group.

=== Ester formation ===
In the presence of acid catalysts, ethanol reacts with [[carboxylic acid]]s to produce ethyl esters and water:
:[[carboxylic acid|RCOOH]] + HOCH<sub>2</sub>CH<sub>3</sub> → [[ester|RCOOCH<sub>2</sub>CH<sub>3</sub>]] + H<sub>2</sub>O
This reaction, which is conducted on large scale industrially, requires the removal of the water from the reaction mixture as it is formed. Esters react in the presence of an acid or base to give back the alcohol and a salt. This reaction is known as [[saponification]] because it is used in the preparation of soap. Ethanol can also form esters with inorganic acids. [[Diethyl sulfate]] and [[triethyl phosphate]] are prepared by treating ethanol with sulfur trioxide and [[phosphorus pentoxide]] respectively. Diethyl sulfate is a useful ethylating agent in [[organic synthesis]]. [[Ethyl nitrite]], prepared from the reaction of ethanol with [[sodium nitrite]] and sulfuric acid, was formerly used as a [[diuretic]].

=== Dehydration ===
In the presence of acid catalysts, alcohols can be converted to alkenes such as ethanol to ethylene. Typically [[solid acid]]s such as [[alumina]] are used.<ref name="UllmannEthylene">{{cite book | first1=Heinz | last1=Zimmermann | first2=Roland | last2=Walz | chapter=Ethylene | title=Ullmann's Encyclopedia of Industrial Chemistry | publisher=Wiley-VCH | location=Weinheim | year=2008 | doi=10.1002/14356007.a10_045.pub3 | isbn=978-3-527-30673-2}}</ref>
:CH<sub>3</sub>CH<sub>2</sub>OH → H<sub>2</sub>C=CH<sub>2</sub> + H<sub>2</sub>O

Since water is removed from the same molecule, the reaction is known as [[Dehydration of alcohols to alkenes|intramolecular dehydration]]. Intramolecular dehydration of an alcohol requires a high temperature and the presence of an acid catalyst such as sulfuric acid.<ref>{{Cite web | date=2016-02-09 | title=14.4: Dehydration Reactions of Alcohols | url=https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Map%3A_Organic_Chemistry_(Wade)/14%3A_Reactions_of_Alcohols/14.04%3A_Dehydration_Reactions_of_Alcohols | access-date=2022-05-09 | website=Chemistry LibreTexts | language=en}}</ref> Ethylene produced from sugar-derived ethanol (primarily in Brazil) competes with ethylene produced from petrochemical feedstocks such as naphtha and ethane.{{citation needed|date=November 2024}} At a lower temperature than that of intramolecular dehydration, [[Dehydration reaction|intermolecular alcohol dehydration]] may occur producing a symmetrical ether. This is a [[condensation reaction]]. In the following example, diethyl ether is produced from ethanol:
:2 CH<sub>3</sub>CH<sub>2</sub>OH → CH<sub>3</sub>CH<sub>2</sub>OCH<sub>2</sub>CH<sub>3</sub> + H<sub>2</sub>O<ref>{{Cite web | date=2013-10-02 | title=Alkenes from Dehydration of Alcohols | url=https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Supplemental_Modules_(Organic_Chemistry)/Alkenes/Synthesis_of_Alkenes/Alkenes_from_Dehydration_of_Alcohols | access-date=2022-05-09 | website=Chemistry LibreTexts | language=en}}</ref>

=== Combustion ===
Complete combustion of ethanol forms carbon dioxide and water:
:C<sub>2</sub>H<sub>5</sub>OH (l) + 3 O<sub>2</sub> (g) → 2 CO<sub>2</sub> (g) + 3 H<sub>2</sub>O (l); −Δ<sub>c</sub>''H'' = 1371&nbsp;kJ/mol<ref>{{cite journal | title=Heats of Formation of Simple Organic Molecules | last=Rossini | first=Frederick D. | name-list-style=vanc | journal=Ind. Eng. Chem. | year=1937 | volume=29 | pages=1424–1430 | doi=10.1021/ie50336a024 | issue=12}}</ref> = 29.8&nbsp;kJ/g = 327&nbsp;kcal/mol = 7.1&nbsp;kcal/g

:C<sub>2</sub>H<sub>5</sub>OH (l) + 3 O<sub>2</sub> (g) → 2 CO<sub>2</sub> (g) + 3 H<sub>2</sub>O (g); −Δ<sub>c</sub>''H'' = 1236&nbsp;kJ/mol = 26.8&nbsp;kJ/g = 295.4&nbsp;kcal/mol = 6.41 kcal/g<ref>Calculated from heats of formation from CRC Handbook of Chemistry and Physics, 49th Edition, 1968–1969.</ref>

Specific heat = 2.44 kJ/(kg·K)

=== Acid-base chemistry ===
Ethanol is a neutral molecule and the [[pH]] of a solution of ethanol in water is nearly 7.00. Ethanol can be quantitatively converted to its [[conjugate base]], the [[Alkoxide|ethoxide]] ion (CH<sub>3</sub>CH<sub>2</sub>O<sup>−</sup>), by reaction with an [[alkali metal]] such as [[sodium]]:<ref name="m_and_b" />
:2 CH<sub>3</sub>CH<sub>2</sub>OH + 2 Na → 2 CH<sub>3</sub>CH<sub>2</sub>ONa + H<sub>2</sub>
or a very strong base such as [[sodium hydride]]:
:CH<sub>3</sub>CH<sub>2</sub>OH + NaH → CH<sub>3</sub>CH<sub>2</sub>ONa + H<sub>2</sub>
The acidities of water and ethanol are nearly the same, as indicated by their [[Acid dissociation constant|pKa]] of 15.7 and 16 respectively. Thus, sodium ethoxide and sodium hydroxide exist in an equilibrium that is closely balanced:
:CH<sub>3</sub>CH<sub>2</sub>OH + NaOH {{eqm}} CH<sub>3</sub>CH<sub>2</sub>ONa + H<sub>2</sub>O

=== Halogenation ===
Ethanol is not used industrially as a precursor to ethyl halides, but the reactions are illustrative. Ethanol reacts with [[hydrogen halide]]s to produce [[haloalkane|ethyl halides]] such as [[ethyl chloride]] and [[ethyl bromide]] via an [[SN2 reaction|S<sub>N</sub>2 reaction]]:
:CH<sub>3</sub>CH<sub>2</sub>OH + [[hydrogen chloride|HCl]] → CH<sub>3</sub>CH<sub>2</sub>Cl + H<sub>2</sub>O
HCl requires a catalyst such as [[zinc chloride]].<ref name="s_and_h">{{cite book | first1=Andrew | last1=Streitwieser | first2=Clayton H. | last2=Heathcock | name-list-style=vanc | author-link1=Andrew Streitwieser | author-link2=Clayton Heathcock | title=Introduction to Organic Chemistry | url=https://archive.org/details/introductiontoor00stre | url-access=registration | year=1976 | publisher=MacMillan | isbn=978-0-02-418010-0}}</ref>
HBr requires [[refluxing]] with a sulfuric acid catalyst.<ref name="s_and_h" /> Ethyl halides can, in principle, also be produced by treating ethanol with more specialized [[Halogenation|halogenating agents]], such as [[thionyl chloride]] or [[phosphorus tribromide]].<ref name="m_and_b" /><ref name="s_and_h" />
:CH<sub>3</sub>CH<sub>2</sub>OH + SOCl<sub>2</sub> → CH<sub>3</sub>CH<sub>2</sub>Cl + SO<sub>2</sub> + HCl

Upon treatment with halogens in the presence of base, ethanol gives the corresponding [[haloform]] (CHX<sub>3</sub>, where X = Cl, Br, I). This conversion is called the [[haloform reaction]].<ref>{{cite book | vauthors=Chakrabartty SK | veditors=Trahanovsky WS | title=Oxidation in Organic Chemistry | pages=343–370 | publisher=Academic Press | location=New York | year=1978}}</ref>
An intermediate in the reaction with chlorine is the [[aldehyde]] called [[chloral]], which forms [[chloral hydrate]] upon reaction with water:<ref name=Ull>{{cite book | last1=Reinhard | first1=Jira | first2=Erwin | last2=Kopp | first3=Blaine C. | last3=McKusick | first4=Gerhard | last4=Röderer | first5=Axel | last5=Bosch | first6=Gerald | last6=Fleischmann | name-list-style=vanc | chapter=Chloroacetaldehydes | title=Ullmann's Encyclopedia of Industrial Chemistry | year=2007 | publisher=Wiley-VCH | location=Weinheim | doi=10.1002/14356007.a06_527.pub2 | isbn=978-3-527-30673-2}}</ref>
:4 Cl<sub>2</sub> + CH<sub>3</sub>CH<sub>2</sub>OH → CCl<sub>3</sub>CHO + 5 HCl
:CCl<sub>3</sub>CHO + H<sub>2</sub>O → CCl<sub>3</sub>C(OH)<sub>2</sub>H

=== Oxidation ===
Ethanol can be oxidized to acetaldehyde and further oxidized to [[acetic acid]], depending on the reagents and conditions.<ref name="s_and_h" /> This oxidation is of no importance industrially, but in the human body, these oxidation reactions are catalyzed by the enzyme [[liver alcohol dehydrogenase|liver ADH]]. The oxidation product of ethanol, acetic acid, is a nutrient for humans, being a precursor to [[acetyl CoA]], where the acetyl group can be spent as energy or used for biosynthesis.

=== Metabolism ===
Ethanol is similar to [[macronutrients]] such as proteins, fats, and carbohydrates in that it provides calories. When consumed and metabolized, it contributes 7&nbsp;kilocalories per gram via [[ethanol metabolism]].<ref>{{Cite journal | last=Cederbaum | first=Arthur I | title=Alcohol Metabolism | date=2012-11-16 | journal=Clinics in Liver Disease | volume=16 | issue=4 | pages=667–685 | doi=10.1016/j.cld.2012.08.002 | issn=1089-3261 | pmc=3484320 | pmid=23101976}}</ref>

== Safety ==
{{See also|Alcohol (chemistry)#Toxicity|Alcohol (drug)#Adverse effects|Health effects of alcohol}}
Ethanol is very flammable and should not be used around an open flame. Atmospheric concentrations above one part per thousand are above the European Union [[occupational exposure limit]]s.<ref name="msdset" />

Pure ethanol will irritate the skin and eyes.<ref>[http://www.nfpa.org/Assets/files/AboutTheCodes/704/CLA-AAA_ROPminutes_01-10.pdf Minutes of Meeting] {{Webarchive|url=https://web.archive.org/web/20210416230440/https://www.nfpa.org/Assets/files/AboutTheCodes/704/CLA-AAA_ROPminutes_01-10.pdf |date=16 April 2021 }}. Technical Committee on Classification and Properties of Hazardous Chemical Data (12–13 January 2010).</ref> Nausea, [[vomiting]], and intoxication are symptoms of ingestion. Long-term use by ingestion can result in serious liver damage.<ref name="msdset">{{cite web | url=http://msds.chem.ox.ac.uk/ET/ethyl_alcohol.html | title=Safety data for ethyl alcohol | publisher=University of Oxford | date=9 May 2008 | access-date=3 January 2011 | archive-date=14 July 2011 | archive-url=https://web.archive.org/web/20110714040451/http://msds.chem.ox.ac.uk/ET/ethyl_alcohol.html }}</ref> Globally, ethanol accounted for 1.8 million deaths in 2021.<ref>https://ourworldindata.org/grapher/deaths-due-to-alcohol-use?tab=discrete-bar&time=2021</ref>

== History ==
{{Further|Liquor}}<!--
[[File:Alcohol flame.jpg|thumb|upright|Ethanol being used as fuel for a burner]]-->

The fermentation of sugar into ethanol is one of the earliest [[biotechnology|biotechnologies]] employed by humans. Ethanol has historically been identified variously as spirit of wine or ardent spirits,<ref>{{Cite book | last=Ottley | first=William Campbell | url=https://books.google.com/books?id=wYcwvwyk2RAC | title=A dictionary of chemistry and of mineralogy as connected with it | date=1826 | publisher=Murray | language=en}}</ref> and as [[aqua vitae]] ([[Latin]] for "water of life") or aqua vita. The intoxicating effects of its consumption have been known since ancient times. Ethanol has been used by humans since prehistory as the intoxicating ingredient of alcoholic beverages. Dried residue on 9,000-year-old pottery found in China suggests that [[Neolithic]] people consumed alcoholic beverages.<ref name="Roach">{{cite journal | vauthors=Roach J | date=18 July 2005 | url=http://news.nationalgeographic.com/news/2005/07/0718_050718_ancientbeer.html | archive-url=https://web.archive.org/web/20050722030635/http://news.nationalgeographic.com/news/2005/07/0718_050718_ancientbeer.html | archive-date=22 July 2005 | title=9,000-Year-Old Beer Re-Created From Chinese Recipe | journal=National Geographic News | access-date=3 September 2007}}</ref>

The inflammable nature of the exhalations of wine was already known to ancient natural philosophers such as [[Aristotle]] (384–322 BCE), [[Theophrastus]] ({{circa|371}}–287 BCE), and [[Pliny the Elder]] (23/24–79 CE).<ref>{{harvnb|Berthelot|Houdas|1893|loc=vol. I, p. 137}}.</ref> However, this did not immediately lead to the isolation of ethanol, despite the development of more advanced distillation techniques in second- and third-century [[Roman Egypt]].<ref>{{harvnb|Berthelot|Houdas|1893|loc=vol. I, pp. 138–139}}.</ref> An important recognition, first found in one of the writings attributed to [[Jabir ibn Hayyan|Jābir ibn Ḥayyān]] (ninth century CE), was that by [[Salt-effect distillation|adding salt]] to boiling wine, which increases the wine's [[relative volatility]], the flammability of the resulting vapors may be enhanced.<ref>{{cite book | last1=al-Hassan | first1=Ahmad Y. | author-link=Ahmad Y. al-Hassan | year=2009 | chapter=Alcohol and the Distillation of Wine in Arabic Sources from the 8th Century | title=Studies in al-Kimya': Critical Issues in Latin and Arabic Alchemy and Chemistry | location=Hildesheim | publisher=Georg Olms Verlag | pages=283–298}} (same content also available on [http://www.history-science-technology.com/notes/notes7.html the author's website] {{Webarchive|url=https://web.archive.org/web/20151229003135/http://www.history-science-technology.com/notes/notes7.html |date=29 December 2015 }}<!-- Please don't remove, this is not a duplicat reference. -->).</ref> The distillation of wine is attested in Arabic works attributed to [[Al-Kindi|al-Kindī]] ({{circa|801}}–873 CE) and to [[Al-Farabi|al-Fārābī]] ({{circa|872}}–950), and in the 28th book of [[Al-Zahrawi|al-Zahrāwī]]'s (Latin: Abulcasis, 936–1013) ''Kitāb al-Taṣrīf'' (later translated into Latin as ''Liber servatoris'').<ref>{{harvnb|al-Hassan|2009}} (same content also available on [http://www.history-science-technology.com/notes/notes7.html the author's website] {{Webarchive|url=https://web.archive.org/web/20151229003135/http://www.history-science-technology.com/notes/notes7.html |date=29 December 2015 }}); cf. {{harvnb|Berthelot|Houdas|1893|loc=vol. I, pp. 141, 143}}. Sometimes, sulfur was also added to the wine (see {{harvnb|Berthelot|Houdas|1893|loc=vol. I, p. 143}}).</ref> In the twelfth century, recipes for the production of ''aqua ardens'' ("burning water", i.e., ethanol) by distilling wine with salt started to appear in a number of Latin works, and by the end of the thirteenth century it had become a widely known substance among Western European chemists.<ref>{{harvnb|Multhauf|1966|pp=204–206}}.</ref>

The works of [[Taddeo Alderotti]] (1223–1296) describe a method for concentrating ethanol involving repeated fractional distillation through a water-cooled [[still]], by which an ethanol purity of 90% could be obtained.<ref>{{cite book | last1=Holmyard | first1=Eric John | author1-link=Eric John Holmyard | date=1957 | title=Alchemy | location=Harmondsworth | publisher=Penguin Books | isbn=978-0-486-26298-7}} pp. 51–52.</ref> The medicinal properties of ethanol were studied by [[Arnald of Villanova]] (1240–1311 CE) and [[John of Rupescissa]] ({{circa|1310}}–1366), the latter of whom regarded it as a life-preserving substance able to prevent all diseases (the ''aqua vitae'' or "water of life", also called by John the ''[[Aether (classical element)|quintessence]]'' of wine).<ref>{{cite book | last=Principe | first=Lawrence M. | author-link=Lawrence M. Principe | year=2013 | title=The Secrets of Alchemy | location=Chicago | publisher=The University of Chicago Press | isbn=978-0-226-10379-2}} pp. 69–71.</ref> In [[China]], archaeological evidence indicates that the true distillation of alcohol began during the [[Jin dynasty (1115–1234)|Jin]] (1115–1234) or [[Southern Song dynasty|Southern Song]] (1127–1279) dynasties.<ref name=haw>{{cite book | last=Haw | first=Stephen G. | name-list-style=vanc | author-link=Stephen G. Haw | title=Marco Polo in China | publisher=Routledge | year=2006 | isbn=978-1-134-27542-7 | chapter=Wine, women and poison | pages=147–148 | chapter-url={{google books | plainurl=y | id=DSfvfr8VQSEC | page=148}} | access-date=10 July 2016 | quote=The earliest possible period seems to be the Eastern Han dynasty... the most likely period for the beginning of true distillation of spirits for drinking in China is during the Jin and Southern Song dynasties}}</ref> A still has been found at an archaeological site in Qinglong, [[Hebei]], dating to the 12th century.<ref name="haw" /> In India, the true distillation of alcohol was introduced from the Middle East, and was in wide use in the [[Delhi Sultanate]] by the 14th century.<ref name="habib">{{cite book | last=Habib | first=Irfan | author-link=Irfan Habib | title=Economic History of Medieval India, 1200–1500 | url={{google books | plainurl=y | id=K8kO4J3mXUAC | page=55}} | year=2011 | publisher=Pearson Education India | isbn=978-81-317-2791-1 | pages=55–}}</ref>

In 1796, German-Russian chemist [[Johann Tobias Lowitz]] obtained pure ethanol by mixing partially purified ethanol (the alcohol-water azeotrope) with an excess of anhydrous alkali and then distilling the mixture over low heat.<ref>{{cite journal | last=Lowitz | first=T. | name-list-style=vanc | journal=Chemische Annalen für die Freunde der Naturlehre, Aerznengelartheit, Haushaltungskunde und Manufakturen | url={{google books | plainurl=y | id=Zws_AAAAcAAJ}} | year=1796 | title=Anzeige eines, zur volkommen Entwasserung des Weingeistes nothwendig zu beobachtenden, Handgriffs | language=de | trans-title=Report of a task that must be done for the complete dehydration of wine spirits [i.e., alcohol-water azeotrope]) | volume=1 | pages=195–204 | quote=See pp. 197–198: Lowitz dehydrated the azeotrope by mixing it with a 2:1 excess of anhydrous alkali and then distilling the mixture over low heat.}}</ref> French chemist [[Antoine Lavoisier]] described ethanol as a compound of carbon, hydrogen, and oxygen, and in 1807 [[Nicolas-Théodore de Saussure]] determined ethanol's chemical formula.<ref>{{cite EB1911|wstitle = Alcohol|volume=1|pages=525–527}}</ref><ref>{{cite journal | last=de Saussure | first=Théodore | name-list-style=vanc | journal=Journal de Physique, de Chimie, d'Histoire Naturelle et des Arts | url={{google books | plainurl=y | id=G-UPAAAAQAAJ | page=316}} | year=1807 | title=Mémoire sur la composition de l'alcohol et de l'éther sulfurique | volume=64 | pages=316–354}} In his 1807 paper, Saussure determined ethanol's composition only roughly; a more accurate analysis of ethanol appears on page 300 of his 1814 paper: {{cite journal | last=de Saussure | first=Théodore | journal=Annales de Chimie et de Physique | url={{google books | plainurl=y | id=ch8zAQAAMAAJ | page=273}} | year=1814 | pages=273–305 | title=Nouvelles observations sur la composition de l'alcool et de l'éther sulfurique | volume=89}}</ref> Fifty years later, [[Archibald Scott Couper]] published the structural formula of ethanol,  one of the first structural formulas determined.<ref name="Couper">{{cite journal | vauthors=Couper AS | year=1858 | title=On a new chemical theory | journal=Philosophical Magazine | format=online reprint | volume=16 | issue=104–116 | url=http://web.lemoyne.edu/~giunta/couper/couper.html | access-date=3 September 2007}}</ref>

Ethanol was first prepared synthetically in 1825 by [[Michael Faraday]]. He found that sulfuric acid could absorb large volumes of [[coal gas]].<ref>{{cite journal | vauthors=Faraday M | year=1825 | url=http://gallica.bnf.fr/ark:/12148/bpt6k559209/f473.image | title=On new compounds of carbon and hydrogen, and on certain other products obtained during the decomposition of oil by heat | journal=Philosophical Transactions of the Royal Society of London | volume=115 | pages=440–466 | doi=10.1098/rstl.1825.0022 | doi-access=free}} In a footnote on page 448, Faraday notes the action of sulfuric acid on coal gas and coal-gas distillate; specifically, "The [sulfuric] acid combines directly with carbon and hydrogen; and I find when [the resulting compound is] united with bases [it] forms a peculiar class of salts, somewhat resembling the sulphovinates [i.e., ethyl sulfates], but still different from them."</ref> He gave the resulting solution to [[Henry Hennell]], a British chemist, who found in 1826 that it contained "sulphovinic acid" (ethyl hydrogen sulfate).<ref>{{cite journal | vauthors=Hennell H | journal=Philosophical Transactions of the Royal Society of London | url={{google books | plainurl=y | id=f05FAAAAcAAJ | page=}} | year=1826 | title=On the mutual action of sulphuric acid and alcohol, with observations on the composition and properties of the resulting compound | volume=116 | pages=240–249 | doi=10.1098/rstl.1826.0021 | s2cid=98278290}} On page 248, Hennell mentions that Faraday gave him some sulfuric acid in which coal gas had dissolved and that he (Hennell) found that it contained "sulphovinic acid" (ethyl hydrogen sulfate).</ref> In 1828, Hennell and the French chemist [[Georges-Simon Serullas]] independently discovered that sulphovinic acid could be decomposed into ethanol.<ref name="Hennell">{{cite journal | vauthors=Hennell H | year=1828 | title=On the mutual action of sulfuric acid and alcohol, and on the nature of the process by which ether is formed | journal=Philosophical Transactions of the Royal Society of London | volume=118 | url={{google books | plainurl=y | id=X-9FAAAAMAAJ | page=365}} | doi=10.1098/rstl.1828.0021 | pages=365–371 | s2cid=98483646}} On page 368, Hennell produces ethanol from "sulfovinic acid" ([[Ethyl sulfate|ethyl hydrogen sulfate]]).</ref><ref>{{cite journal | last=Sérullas | first=Georges-Simon | editor-first1=Louis-Bernard | editor-last1=Guyton de Morveau | editor-first2=Joseph Louis | editor-last2=Gay-Lussac | editor-first3=François | editor-last3=Arago | editor4=Michel Eugène Chevreul | editor5=Marcellin Berthelot | editor6=Éleuthère Élie Nicolas Mascart | editor7=Albin Haller | name-list-style=vanc | journal=Annales de Chimie et de Physique | url={{google books | plainurl=y | id=ZxUAAAAAMAAJ | page=152}} | year=1828 | title=De l'action de l'acide sulfurique sur l'alcool, et des produits qui en résultent | volume=39 | pages=152–186}} On page 158, Sérullas mentions the production of alcohol from "sulfate acid d'hydrogène carboné" (hydrocarbon acid sulfate).</ref> Thus, in 1825 Faraday had unwittingly discovered that ethanol could be produced from ethylene (a component of coal gas) by [[Acid catalysis|acid-catalyzed]] hydration, a process similar to current industrial ethanol synthesis.<ref>In 1855, the French chemist [[Marcellin Berthelot]] confirmed Faraday's discovery by preparing ethanol from pure ethylene. {{cite journal | first=Marcellin | last=Berthelot | editor-first1=François | editor-last1=Arago | editor-first2=Joseph Louis | editor-last2=Gay-Lussac | name-list-style=vanc | journal=Annales de Chimie et de Physique | url={{google books | plainurl=y | id=1ClCAAAAcAAJ | page=385}} | year=1855 | title=Sur la formation de l'alcool au moyen du bicarbure d'hydrogène (On the formation of alcohol by means of ethylene) | volume=43 | pages=385–405}} (Note: The chemical formulas in Berthelot's paper are wrong because chemists at that time used the wrong atomic masses for the elements; e.g., carbon (6 instead of 12), oxygen (8 instead of 16), etc.)</ref>

Ethanol was used as lamp fuel in the U.S. as early as 1840, but a tax levied on industrial alcohol during the [[American Civil War|Civil War]] made this use uneconomical. The tax was repealed in 1906.<ref name="siegel">{{cite news | url=https://www.npr.org/templates/story/story.php?storyId=7426827 | title=Ethanol, Once Bypassed, Now Surging Ahead | last=Siegel | first=Robert | name-list-style=vanc | publisher=NPR | date=15 February 2007 | access-date=22 September 2007}}</ref> Use as an automotive fuel dates back to 1908, with the [[Ford Model T]] able to run on [[petrol]] (gasoline) or ethanol.<ref name="dipardo">{{cite web | url=http://www.eia.gov/oiaf/analysispaper/pdf/biomass.pdf | title=Outlook for Biomass Ethanol Production and Demand | publisher=United States Department of Energy | last=DiPardo | first=Joseph | name-list-style=vanc | access-date=22 September 2007 | archive-url=https://web.archive.org/web/20150924050511/http://www.eia.gov/oiaf/analysispaper/pdf/biomass.pdf | archive-date=24 September 2015 }}</ref> It fuels some [[spirit lamps]].

Ethanol intended for industrial use is often produced from ethylene.<ref name="myers">{{Cite book | last1=Myers | first1=Richard L. | last2=Myers | first2=Rusty L. | name-list-style=vanc | title=The 100 most important chemical compounds: a reference guide | year=2007 | publisher=Greenwood Press | location=Westport, CN | isbn=978-0-313-33758-1 | page=122 | url={{google books | plainurl=y | id=0AnJU-hralEC | page=122}}}}</ref> Ethanol has widespread use as a solvent of substances intended for human contact or consumption, including scents, flavorings, colorings, and medicines. In chemistry, it is both a solvent and a feedstock for the synthesis of other products. It has a long history as a fuel for heat and light, and more recently as a fuel for internal combustion engines.

== See also ==
{{Div col|colwidth=30em}}
* [[Ethanol-induced non-lamellar phases in phospholipids]]
* [[Methanol]]
* [[1-Propanol]]
* [[2-Propanol]]
* [[Rubbing alcohol]]
* [[tert-Butyl alcohol]]
* [[Butanol fuel]]
* [[Timeline of alcohol fuel]]
{{Div col end}}

== References ==
{{Reflist|30em}}

== Further reading ==
* {{cite web | last1=Boyce | first1=John M | last2=Pittet | first2=Didier | name-list-style=vanc | year=2003 | url=http://cdc.gov/handhygiene/ | title=Hand Hygiene in Healthcare Settings | publisher=[[Centers for Disease Control]] | location=Atlanta, GA | ref=none}}
* {{cite conference | url=http://lib.dr.iastate.edu/abe_eng_conf/68/ | title=Ethanol production, purification, and analysis techniques: a review | first1=Shinnosuke | last1=Onuki | first2=Jacek A. | last2=Koziel | first3=Johannes | last3=van Leeuwen | first4=William S. | last4=Jenks | first5=David | last5=Grewell | first6=Lingshuang | last6=Cai | name-list-style=vanc | date=June 2008 | conference=2008 ASABE Annual International Meeting | location=Providence, RI | access-date=16 February 2013 | ref=none}}
* {{cite web | url=http://sci-toys.com/ingredients/alcohol.html | website=Sci-toys | title=Explanation of US denatured alcohol designations | ref=none}}
* {{cite book | last=Lange | first=Norbert Adolph | editor=John Aurie Dean | title=Lange's Handbook of Chemistry | url=https://books.google.com/books?id=4YlqAAAAMAAJ | edition=10th | year=1967 | publisher=McGraw-Hill | ref=none}}
* {{Cite encyclopedia | title=Alcohols | encyclopedia=Encyclopedia of Liquid Fuels | publisher=De Gruyter | last=Schmidt | first=Eckart W. | date=2022 | pages=12–32 | doi=10.1515/9783110750287-001 | isbn=978-3-11-075028-7 | chapter=Ethanol}}

== External links ==
{{Wiktionary|alcohol|ethanol}}
{{Commons}}
* [http://www.periodicvideos.com/videos/mv_alcohol.htm Alcohol (Ethanol)] at ''[[The Periodic Table of Videos]]'' (University of Nottingham)
* [http://www.inchem.org/documents/icsc/icsc/eics0044.htm International Labour Organization] ethanol safety information
* [http://www.npi.gov.au/substances/ethanol/index.html National Pollutant Inventory – Ethanol Fact Sheet]
* [https://www.cdc.gov/niosh/npg/npgd0262.html CDC – NIOSH Pocket Guide to Chemical Hazards – Ethyl Alcohol]
* [http://webbook.nist.gov/cgi/cbook.cgi?Name=ethanol&Units=SI National Institute of Standards and Technology] chemical data on ethanol
* [http://www.cmegroup.com/company/cbot.html Chicago Board of Trade] news and market data on ethanol futures
* Calculation of [http://ddbonline.ddbst.de/AntoineCalculation/AntoineCalculationCGI.exe?component=Ethanol vapor pressure], [http://ddbonline.ddbst.de/DIPPR105DensityCalculation/DIPPR105CalculationCGI.exe?component=Ethanol liquid density], [http://ddbonline.ddbst.de/VogelCalculation/VogelCalculationCGI.exe?component=Ethanol dynamic liquid viscosity], [http://ddbonline.ddbst.de/DIPPR106SFTCalculation/DIPPR106SFTCalculationCGI.exe?component=Ethanol surface tension] of ethanol
* [https://www.ethanolhistory.com/ Ethanol History] A look into the history of ethanol
* [http://chemsub.online.fr/name/ethyl_alcohol.html ChemSub Online: Ethyl alcohol]
* [https://web.archive.org/web/20170210214845/http://www.inclusive-science-engineering.com/industrial-alcohol-production-from-ethylene-and-sulphuric-acid/industrial-ethyl-alcohol-production-from-ethylene-and-sulphuric-acid/ Industrial ethanol production process flow diagram using ethylene and sulphuric acid]

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