Editing Ethylene glycol

{{Short description|Organic compound ethane-1,2-diol}}
{{distinguish|text=[[Polyethylene glycol]], [[Diethylene glycol]], [[Propylene glycol]], or [[Diol|Glycol]]}}{{Chembox
| Verifiedfields = changed
| Watchedfields  = changed
| verifiedrevid  = 457630599
| Name           = 
| ImageFile      = 
| ImageFile1     = Ethylene glycol.svg
| ImageName1     = Wireframe model of ethylene glycol
| ImageFileL2    = Ethylene-glycol-3D-vdW.png
| ImageNameL2    = Spacefill model of ethylene glycol
| ImageFileR2    = Ethylene-glycol-3D-balls.png
| ImageNameR2    = Ball and stick model of ethylene glycol
| ImageFile3     = Samlpe of Ethylene glycol.jpg
| ImageName3     = Sample of ethylene glycol
| PIN            = Ethane-1,2-diol<ref>{{cite book |author=[[International Union of Pure and Applied Chemistry]] |date=2014 |title=Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 |publisher=[[Royal Society of Chemistry|The Royal Society of Chemistry]] |pages=690 |doi=10.1039/9781849733069 |isbn=978-0-85404-182-4}}</ref>
| OtherNames     = {{ubl|Ethylene glycol|1,2-Ethanediol|Ethylene alcohol|Hypodicarbonous acid|Monoethylene glycol|1,2-Dihydroxyethane|Glycol solvent}}
| IUPACName      = Ethylene glycol<ref>{{cite web | url=https://www.ebi.ac.uk/chebi/searchId.do?chebiId=30742 | title=Ethylene glycol (CHEBI:30742) }}</ref><br>Ethane-1,2-diol<ref>{{cite web | url=https://www.ebi.ac.uk/chebi/searchId.do?chebiId=30742 | title=Ethylene glycol (CHEBI:30742) }}</ref>
| Section1       = {{Chembox Identifiers
| Abbreviations = MEG
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| ChEMBL = 457299
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/C2H6O2/c3-1-2-4/h3-4H,1-2H2
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = LYCAIKOWRPUZTN-UHFFFAOYSA-N
| CASNo = 107-21-1
| CASNo_Ref = {{cascite|correct|CAS}}
| PubChem = 174
| ChemSpiderID = 13835235
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = FC72KVT52F
| EINECS = 203-473-3
| DrugBank_Ref = {{drugbankcite|changed|drugbank}}
| DrugBank = 
| KEGG_Ref = {{keggcite|correct|kegg}}
| KEGG = C01380
| MeSHName = Ethylene+glycol
| ChEBI_Ref = {{ebicite|correct|EBI}}
| ChEBI = 30742
| RTECS = KW2975000
| UNNumber = 3082
| SMILES = OCCO
| InChI = 1/C2H6O2/c3-1-2-4/h3-4H,1-2H2
| InChIKey = LYCAIKOWRPUZTN-UHFFFAOYAD
| Beilstein = 505945
| Gmelin = 943
| 3DMet = B00278
  }}
| Section2       = {{Chembox Properties
| C=2 | H=6 | O=2
| Appearance = colorless liquid
| Odor = Odorless<ref name=PGCH/>
| Density = {{cvt|1.1132|g/cm3}}
| MeltingPtC = −12.9
| MeltingPt_notes = 
| BoilingPtC = 197.3
| BoilingPt_notes = 
| Solubility = [[Miscible]]
| SolubleOther = Soluble in alcohols, ethyl acetate, THF, and dioxane. Miscible with DCM and slightly miscible with diethyl ether. Not miscible with toluene or hexanes.
| Solvent = 
| VaporPressure = 7.99 Pa (20 °C)<ref name=PGCH/>
| Viscosity = 1.61{{e|-2}} Pa·s<ref>{{cite web|url=http://physics.info/viscosity/|title=Viscosity|first=Glenn|last=Elert|website=The Physics Hypertextbook|access-date=2007-10-02}}</ref>
| HenryConstant = 
| AtmosphericOHRateConstant = 
| pKa = 
| pKb =
| LogP = −1.69<ref name="chemsrc">{{Cite web|url=https://www.chemsrc.com/en/cas/107-21-1_329621.html|title=Ethylene glycol|website=www.chemsrc.com}}</ref>
  }}
| Section3       = 
| Section4       = {{Chembox Thermochemistry
| DeltaHf = −460 kJ/mol
| DeltaHc = 
| Entropy = 166.9 J/(mol·K)
| HeatCapacity = 149.5 J/(mol·K)
  }}
| Section5       = 
| Section6       = 
| Section7       = {{Chembox Hazards
| MainHazards= Harmful, produces poisonous [[oxalic acid]] when ingested, flammable 
| NFPA-H = 2
| NFPA-F = 1
| NFPA-R = 0
| NFPA-S = 
| GHSPictograms = {{GHS07}}{{GHS08}} 
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|302|373}}
| PPhrases = {{P-phrases|260|264|270|301+312|302|314|330|501}}
| ExternalSDS = [https://www.fishersci.com/msdsproxy%3FproductName%3DE1774%26productDescription%3DETHYLENE%2BGLYCOL%2BLABORATORY%2B4L%26catNo%3DE177-4%2B%26vendorId%3DVN00033897%26storeId%3D10652 External SDS 1]
[https://www.sigmaaldrich.com/GB/cs/sds/sial/324558 External SDS 2]
| FlashPtC = 111
| FlashPt_notes = closed&nbsp;cup
| AutoignitionPtC = 410
| ExploLimits = 3.2–15.2%<ref name=PGCH/>
| PEL = None<ref name=PGCH>{{PGCH|0272}}</ref>
| REL = None established<ref name=PGCH/>
| IDLH = None<ref name=PGCH/>
  }}
| Section8       = {{Chembox Related
| OtherFunction = {{ubl|[[Propylene glycol]]|[[Diethylene glycol]]|[[Triethylene glycol]]|[[Polyethylene glycol]]}}
| OtherFunction_label = [[diol]]s
| OtherCompounds =
  }}
}}

'''Ethylene glycol''' ([[IUPAC nomenclature|IUPAC name]]: ethane-1,2-diol) is an [[organic compound]] (a [[Diol#Vicinal diols|vicinal diol]]<ref>{{Cite web |date=2018-10-13 |title=3.8: 3.8 Alcohols - Classification and Nomenclature |url=https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Map%3A_Organic_Chemistry_(Wade)/03%3A_Functional_Groups_and_Nomenclature/3.08%3A_3.8_Alcohols_-__Classification_and_Nomenclature |access-date=2022-04-21 |website=Chemistry LibreTexts |language=en}}</ref>) with the formula {{chem2|(CH_{2}OH)_{2} }}. It is mainly used for two purposes: as a raw material in the manufacture of polyester fibers and for [[antifreeze]] formulations. It is an odorless, colorless, flammable, viscous liquid. It has a sweet taste, but is [[ethylene glycol poisoning|toxic in high concentrations]]. This molecule has been observed in outer space.<ref>{{cite journal |author1= J. M. Hollis |author2=F. J. Lovas |author3=P. R. Jewell |author4=L. H. Coudert | title = Interstellar Antifreeze: Ethylene Glycol| journal = The Astrophysical Journal | volume = 571|issue =1 | pages = L59–L62 | date = 2002-05-20 | doi = 10.1086/341148 | bibcode=2002ApJ...571L..59H|s2cid=56198291 | doi-access = }}</ref>

== Production ==
===Industrial routes===
Ethylene glycol is produced from [[ethylene]] (ethene), via the intermediate [[ethylene oxide]]. Ethylene oxide reacts with [[water]] to produce ethylene glycol according to the [[chemical equation]]

: {{chem2|C_{2}H_{4}O + H_{2}O -> HO\sCH_{2}CH_{2}\sOH}}

This [[chemical reaction|reaction]] can be [[catalyst|catalyzed]] by either [[acid]]s or [[Base (chemistry)|bases]], or can occur at neutral [[pH]] under elevated temperatures. The highest yields of ethylene glycol occur at acidic or neutral pH with a large excess of water. Under these conditions, ethylene glycol yields of 90% can be achieved. The major byproducts are the oligomers [[diethylene glycol]], [[triethylene glycol]], and [[tetraethylene glycol]]. The separation of these oligomers and water is energy-intensive. World production of ethylene glycol was ~20&nbsp;Mt in 2010.<ref name="YueZhaoMa2012">{{cite journal |last1=Yue |first1=Hairong |last2=Zhao |first2=Yujun |last3=Ma |first3=Xinbin |last4=Gong |first4=Jinlong |title=Ethylene glycol: properties, synthesis, and applications |journal=Chemical Society Reviews |date=2012 |volume=41 |issue=11 |pages=4218–4244 |issn=0306-0012 |eissn=1460-4744 |doi=10.1039/c2cs15359a |pmid=22488259}}</ref>

A higher selectivity is achieved by the use of [[Royal Dutch Shell|Shell]]'s [[OMEGA process]]. In the OMEGA process, the ethylene oxide is first converted with [[carbon dioxide]] ({{CO2}}) to [[ethylene carbonate]]. This ring is then hydrolyzed with a base catalyst in a second step to produce mono-ethylene glycol in 98% selectivity.<ref>Scott D. Barnicki, "Synthetic Organic Chemicals", in ''Handbook of Industrial Chemistry and Biotechnology'' edited by James A. Kent, New York: Springer, 2012. 12th&nbsp;ed. {{ISBN|978-1-4614-4259-2}}.</ref> The carbon dioxide is released in this step again and can be fed back into the process circuit. The carbon dioxide comes in part from ethylene oxide production, where a part of the ethylene is completely [[oxidation|oxidized]].

Ethylene glycol is produced from [[carbon monoxide]] in countries with large coal reserves and less stringent environmental regulations. The oxidative carbonylation of methanol to [[dimethyl oxalate]] provides a promising approach to the production of {{chem|C|1}}-based ethylene glycol.<ref>{{cite web |url=http://www.chemsystems.com/reports/search/docs/prospectus/stmc10_coal_meg.pdf |title=Coal to MEG, Changing the Rules of the Game |website=Nexant/Chemsystems |access-date=2016-08-08 |url-status=dead |archive-url=https://web.archive.org/web/20110714135349/http://www.chemsystems.com/reports/search/docs/prospectus/stmc10_coal_meg.pdf |archive-date=July 14, 2011}} (PDF; 5.4&nbsp;MB), 2011 Prospectus.</ref> Dimethyl oxalate can be converted into ethylene glycol in high yields (94.7%)<ref>{{cite patent |country=EP |number=046 983 |status= |title=Process for continuously preparing ethylene glycol |pubdate= |gdate= |fdate=1982-03-10 |pridate= |inventor = |invent1=S. Tahara et al. |assign1=Ube Industries}} and H. T. Teunissen and C. J. Elsevier, ''Ruthenium catalyzed hydrogenation of dimethyl oxalate to ethylene glycol'', J. Chem. Soc., Chem. Commun., 1997, 667–668), {{DOI|10.1039/A700862G}}.</ref> by [[hydrogenation]] with a copper catalyst:<ref>S. Zhang et al., ''Highly-Dispersed Copper-Based Catalysts from Cu–Zn–Al Layered Double Hydroxide Precursor for Gas-Phase Hydrogenation of Dimethyl Oxalate to Ethylene Glycol'', Catalysis Letters, Sept. 2012, '''142''' (9), 1121–1127, {{DOI|10.1007/s10562-012-0871-8}}.</ref>

[[File:MEG ex CO.svg|center]]

Because the methanol is recycled, only carbon monoxide, hydrogen, and oxygen are consumed. One plant with a production capacity of {{val|200000|u=tons}} of ethylene glycol per year is in [[Inner Mongolia]], and a second plant in the Chinese province of [[Henan]] with a capacity of {{val|250000|u=tons per year}} was scheduled for 2012.<ref>{{Cite web |url=http://www.icis.com/resources/news/2012/01/30/9527520/china-s-coal-based-chemicals-are-a-trade-off/ |title=China's coal-based chemicals are a trade-off |author=Clay Boswell |date=30 Jan 2012 |publisher=Independent Commodity Intelligence Services}}</ref> {{As of|2015}}, four plants in China with a capacity of {{val|200000|u=t/a}} each were operating, with at least 17 more to follow.<ref>{{Cite book |url=https://books.google.com/books?id=EPCeBgAAQBAJ&q=meg+china+synthesis+gas&pg=PA15 |title=Industrial Coal Gasification Technologies Covering Baseline and High-Ash Coal |isbn=978-3-527-33690-6 |last1=Gräbner |first1=Martin |date=2014-11-24 |publisher=John Wiley & Sons}}</ref>

===Biological routes===
Ethylene glycol can be produced by recycling its polymeric derivatives, such as [[polyethylene terephthalate]].<ref>{{cite journal |doi=10.1021/acs.chemrev.2c00644 |title=Enzymes' Power for Plastics Degradation |date=2023 |last1=Tournier |first1=Vincent |last2=Duquesne |first2=Sophie |last3=Guillamot |first3=Frédérique |last4=Cramail |first4=Henri |last5=Taton |first5=Daniel |last6=Marty |first6=Alain |last7=André |first7=Isabelle |journal=Chemical Reviews |volume=123 |issue=9 |pages=5612–5701 |pmid=36916764 |url=https://hal.science/hal-04150645/file/Andre_Chemical_Reviews_HAL.pdf }}</ref>

=== Historical routes ===
According to most sources, French chemist [[Charles-Adolphe Wurtz]] (1817–1884) first prepared ethylene glycol in 1856.<ref>{{cite journal | author = Adolphe Wurtz | author-link = Charles-Adolphe Wurtz | date = 1856 | url = http://gallica.bnf.fr/ark:/12148/bpt6k3000k/f203.image | title = Sur le glycol ou alcool diatomique |trans-title=On glycol or dibasic alcohol | journal = Comptes Rendus | volume = 43 | pages = 199–204}}</ref>  He first treated "ethylene iodide" ([[1,2-Diiodoethane]]) with silver acetate and then hydrolyzed the resultant "ethylene diacetate" with [[potassium hydroxide]]. Wurtz named his new compound "glycol" because it shared qualities with both [[ethyl alcohol]] (with one hydroxyl group) and [[glycerin]] (with three hydroxyl groups).<ref>Wurtz (1856), page 200: ''"… je propose de le nommer ''glycol'', parce qu'il se rapproche à la fois, par ses propriétés, de l'alcool proprement dit et de la glycérin, entre lesquels il se trouve placé."'' ( … I propose to call it ''glycol'' because, by its properties, it is simultaneously close to [ethyl] alcohol properly called and glycerin, between which it is placed.)</ref> In 1859, Wurtz prepared ethylene glycol via the [[Hydration reaction|hydration]] of [[ethylene oxide]].<ref>Ad. Wurtz (1859) [http://gallica.bnf.fr/ark:/12148/bpt6k3006f/f815.item.r=.zoom "Synthèse du glycol avec l'oxyde d'éthylène et l'eau"] (Synthesis of glycol from ethylene oxide and water), ''Comptes rendus'', '''49''' :  813–815.</ref> There appears to have been no commercial manufacture or application of ethylene glycol prior to [[World War I]], when it was synthesized from [[ethylene dichloride]] in Germany and used as a substitute for [[glycerol]] in the [[explosives]] industry.

In the United States, semicommercial production of ethylene glycol via [[ethylene chlorohydrin]] started in 1917. The first large-scale commercial glycol plant was erected in 1925 at [[South Charleston, West Virginia]], by Carbide and Carbon Chemicals Co. (now [[Union Carbide]] Corp.). By 1929, ethylene glycol was being used by almost all [[dynamite]] manufacturers. In 1937, Carbide started up the first plant based on Lefort's process for vapor-phase oxidation of ethylene to ethylene oxide. Carbide maintained a monopoly on the direct oxidation process until 1953 when the Scientific Design process was commercialized and offered for licensing.

== Uses ==
===Coolant and heat-transfer agent===
A major use of ethylene glycol is as an antifreeze agent in [[coolant]]s. This can be useful for automobiles and [[air-conditioning]] systems that either have external [[chiller]]s or [[Air handler|air handlers]], or must cool below the freezing temperature of water. In [[geothermal heating]]/cooling systems, ethylene glycol is the [[fluid]] that transports heat through the use of a [[geothermal heat pump]].  The ethylene glycol either gains energy from the source (lake, ocean, [[water well]]) or dissipates heat to the sink, depending on whether the system is being used for heating or cooling.

Pure ethylene glycol has a [[specific heat capacity]] about one half that of water.  So, while providing freeze protection and an increased boiling point, ethylene glycol lowers the specific heat capacity of water mixtures relative to pure water.  A 1:1 mix by mass has a specific heat capacity of about 3140 J/(kg·°C) (0.75 BTU/(lb·°F)), three quarters that of pure water, thus requiring increased flow rates in same-system comparisons with water.

The mixture of ethylene glycol with water provides additional benefits to coolant and antifreeze solutions, such as preventing corrosion and acid degradation, as well as inhibiting the growth of most microbes and fungi.<ref>{{Cite web|url=http://www.hydratechglobal.net/technical/Ethylene+Glycol/58/en|title=Hydratech - Specialist Fluid Solutions|website=www.hydratechglobal.net|access-date=2020-02-24|archive-date=2021-05-14|archive-url=https://web.archive.org/web/20210514041855/http://www.hydratechglobal.net/technical/Ethylene+Glycol/58/en|url-status=dead}}</ref> Mixtures of ethylene glycol and water are sometimes informally referred to in industry as glycol concentrates, compounds, mixtures, or solutions.

Table of thermal and physical properties of saturated liquid ethylene glycol:<ref>{{Cite book |last=Holman |first=Jack P. |title=Heat Transfer |publisher=McGraw-Hill Companies, Inc |year=2002 |isbn=9780072406559 |edition=9th |location=New York, NY |pages=600–606 |language=English}}</ref><ref>{{Cite book |author=Frank P. Incropera, David P. Dewitt, heodore L. Bergman, Adrienne S. Lavigne |title=Fundamentals of Heat and Mass Transfer |publisher=John Wiley and Sons, Inc. |year=2007 |isbn=9780471457282 |edition=6th |location=Hoboken, NJ |pages=941–950 |language=English}}</ref>
{|class="wikitable mw-collapsible"
!Temperature (°C)
!Density (kg/m<sup>3</sup>)
!Specific heat (kJ/(kg·K))
!Kinematic viscosity (m<sup>2</sup>/s)
!Conductivity (W/(m⋅K))
!Thermal diffusivity (m<sup>2</sup>/s)
!Prandtl number
!Thermal expansivity (K<sup>−1</sup>)
|-
|0
|1130.75
|2.294
|{{val|7.53E-5}}
|0.242
|{{val|9.34E-8}}
|615
|{{val|6.50E-4}}
|-
|20
|1116.65
|2.382
|{{val|1.92E-5}}
|0.249
|{{val|9.39E-8}}
|204
|{{val|6.50E-4}}
|-
|40
|1101.43
|2.474
|{{val|8.69E-6}}
|0.256
|{{val|9.39E-8}}
|93
|{{val|6.50E-4}}
|-
|60
|1087.66
|2.562
|{{val|4.75E-6}}
|0.26
|{{val|9.32E-8}}
|51
|{{val|6.50E-4}}
|-
|80
|1077.56
|2.65
|{{val|2.98E-6}}
|0.261
|{{val|9.21E-8}}
|32.4
|{{val|6.50E-4}}
|-
|100
|1058.5
|2.742
|{{val|2.03E-6}}
|0.263
|{{val|9.08E-8}}
|22.4
|{{val|6.50E-4}}
|}

===Anti-freeze===
Pure ethylene glycol freezes at about &minus;12&nbsp;°C (10.4&nbsp;°F) but, when mixed with water, the mixture freezes at a lower temperature. For example, a mixture of 60% ethylene glycol and 40% water freezes at &minus;45&nbsp;°C (&minus;49&nbsp;°F).<ref name=Ullmanns>{{Ullmann | author1 = Siegfried Rebsdat | author2 = Dieter Mayer | title = Ethylene Glycol | doi = 10.1002/14356007.a10_101}}</ref> [[Diethylene glycol]] behaves similarly. The freezing point depression of some mixtures can be explained as a [[colligative property]] of solutions but, in highly concentrated mixtures such as the example, deviations from ideal solution behavior are expected due to the influence of [[intermolecular forces]]. It's important to note that though pure and distilled water will have a greater specific heat capacity than any mixture of antifreeze and water, commercial antifreezes also typically contain an anti-corrosive additive to prevent pure water from corroding coolant passages in the engine block, cylinder head(s), water pump and radiator.

There is a difference in the mixing ratio, depending on whether it is ethylene glycol or propylene glycol. For ethylene glycol, the mixing ratios are typically 30/70 and 35/65, whereas the propylene glycol mixing ratios are typically 35/65 and 40/60. It is important that the mixture be frost-proof at the lowest operating temperature.<ref>{{Cite web|url=https://lcglad.dk/glycol/|title=Glycol til industri og erhverv|website=LC Glad|via=lcglad.dk|language=da|trans-title=Glycol for industry and business}}</ref>

Because of the depressed freezing temperatures, ethylene glycol is used as a [[de-icing]] fluid for [[windshield]]s and aircraft, as an [[antifreeze (coolant)|antifreeze]] in automobile engines, and as a component of [[Cryopreservation#Vitrification|vitrification]] (anticrystallization) mixtures for low-temperature preservation of biological tissues and organs.

The use of ethylene glycol not only depresses the freezing point of aqueous mixtures, but also elevates their boiling point. This results in the operating temperature range for heat-transfer fluids being broadened on both ends of the temperature scale. The increase in boiling temperature is due to pure ethylene glycol having a much higher boiling point and lower [[vapor pressure]] than pure water.

===Precursor to polymers===
[[File:PET.svg|thumb|upright|Ethylene glycol is one precursor to [[polyethyleneterephthalate]], which is produced on the multimillion ton scale annually.]]
In the [[plastics industry|plastic industry]], ethylene glycol is an important precursor to [[polyester]] fibers and [[resin]]s. [[Polyethylene terephthalate]], used to make [[plastic bottle]]s for [[soft drink]]s, is prepared from ethylene glycol.

===Other uses===
====Dehydrating agent====
Ethylene glycol is used in the natural gas industry to remove water vapor from natural gas before further processing, in much the same manner as [[triethylene glycol]] (TEG).

====Hydrate inhibition====
Because of its high boiling point and affinity for water, ethylene glycol is a useful [[desiccant]]. Ethylene glycol is widely used to inhibit the formation of [[Methane clathrate|natural gas clathrates]] (hydrates) in long multiphase pipelines that convey natural gas from remote gas fields to a gas processing facility. Ethylene glycol can be recovered from the natural gas and reused as an inhibitor after purification treatment that removes water and inorganic salts.

Natural gas is dehydrated by ethylene glycol. In this application, ethylene glycol flows down from the top of a tower and meets a rising mixture of water vapor and [[hydrocarbon]] gases. Dry gas exits from the top of the tower. The glycol and water are separated, and the glycol recycled. Instead of removing water, ethylene glycol can also be used to depress the temperature at which [[hydrate]]s are formed. The purity of glycol used for hydrate suppression (monoethylene glycol) is typically around 80%, whereas the purity of glycol used for dehydration (triethylene glycol) is typically 95 to more than 99%. Moreover, the injection rate for hydrate suppression is much lower than the circulation rate in a [[glycol dehydration]] tower.

====Precursor to other chemicals====
Minor uses of ethylene glycol include the manufacture of capacitors, as a chemical intermediate in the manufacture of [[1,4-Dioxane|1,4-dioxane]], as an additive to prevent [[corrosion]] in liquid cooling systems for [[personal computer]]s, and inside the lens devices of cathode-ray tube type of rear projection televisions. Ethylene glycol is also used in the manufacture of some [[vaccine]]s, but it is not itself present in these injections. It is used as a minor (1–2%) ingredient in [[shoe polish]] and also in some inks and dyes. Ethylene glycol has seen some use as a rot and fungal treatment for wood, both as a preventative and a treatment after the fact. It has been used in a few cases to treat partially rotted wooden objects to be displayed in museums. It is one of only a few treatments that are successful in dealing with rot in wooden boats, and is relatively cheap. Ethylene glycol may also be one of the minor ingredients in screen cleaning solutions, along with the main ingredient [[isopropyl alcohol]]. Ethylene glycol is commonly used as a [[preservative]] for biological specimens, especially in secondary schools during [[dissection]] as a safer alternative to [[formaldehyde]]. It is also used as part of the water-based hydraulic fluid used to control subsea oil and gas production equipment.

===Organic building block===
Although dwarfed by its use as a precursor to [[polyester]]s, ethylene glycol is useful in more specialized areas of organic chemistry.  

It serves as a [[protecting group]] in [[organic synthesis]] for manipulation of [[ketones]] and aldehydes.<ref>{{cite web | url = http://www.synarchive.com/protecting-group/Aldehyde_Ketone_Ethylene_glycol_acetal | title = Ethylene glycol acetal | website = The Organic Synthesis Archive | publisher = synarchive.com}}</ref><ref name  = greene>{{cite book | title = Protective Groups in Organic Synthesis | edition = Third |author1=Theodora W. Greene |author2=Peter G. M. Wuts | publisher = John Wiley & Sons | isbn = 978-0-471-16019-9 | pages = 312–322 | year = 1999}}</ref> By reacting with the carbonyl to form and acetal product, it reduces the likelihood of nucleophilic attack at that carbonyl carbon. After the desired reaction is completed, the carbonyl can be regenerated using acid-catalyzed hydrolysis. In one example, [[isophorone]] was protected using ethylene glycol:<ref>{{cite journal |author1=J. H. Babler |author2=N. C. Malek |author3=M. J. Coghlan | title = Selective hydrolysis of α,β- and β,γ-unsaturated ketals: method for deconjugation of β,β-disubstituted α,β-unsaturated ketones | year = 1978 | journal = [[J. Org. Chem.]] | volume = 43 | issue = 9 | pages = 1821–1823 | doi = 10.1021/jo00403a047}}</ref>
[[Image:Ethylene glycol protecting group.png|450px|center]]

The glycol-derived [[dioxalane]] of [[ethyl acetoacetate]] is a commercial fragrance [[fructone]].<ref>{{cite book |doi=10.1002/14356007.t11_t02 |chapter=Flavors and Fragrances, 3. Aromatic and Heterocyclic Compounds |title=Ullmann's Encyclopedia of Industrial Chemistry |date=2016 |last1=Panten |first1=Johannes |last2=Surburg |first2=Horst |pages=1–45 |isbn=978-3-527-30673-2 }}</ref>

==Miscellaneous chemical reactions==
Silicon dioxide dissolves slowly in hot ethylene glycol in the presence of [[alkali metal]] base to produce silicates.<ref name=Laine>{{cite journal|last1=Laine|first1=Richard M.|last2=Blohowiak|first2=Kay Youngdahl|last3=Robinson|first3=Timothy R.|last4=Hoppe|first4=Martin L.|last5=Nardi|first5=Paola|last6=Kampf|first6=Jeffrey|last7=Uhm|first7=Jackie|title=Synthesis of pentacoordinate silicon complexes from SiO<sub>2</sub>|journal=Nature|volume=353|date=17 October 1991|issue=6345|pages=642–644|doi=10.1038/353642a0|bibcode=1991Natur.353..642L|url=https://deepblue.lib.umich.edu/bitstream/2027.42/62810/1/353642a0.pdf|hdl=2027.42/62810|s2cid=4310228|hdl-access=free}}</ref> 

== Toxicity ==
{{main|Ethylene glycol poisoning}}
Ethylene glycol has relatively high mammalian toxicity when ingested, roughly on par with [[methanol]], with an oral [[Lowest published lethal dose|LD<sub>Lo</sub>]] = 786&nbsp;mg/kg for humans.<ref>{{cite web
| author = Safety Officer in Physical Chemistry
| title = Safety (MSDS) data for ethylene glycol
| publisher = Oxford University
| date = November 23, 2009
| url = http://msds.chem.ox.ac.uk/ET/ethylene_glycol.html
| access-date = December 30, 2009
| archive-date = December 14, 2011
| archive-url = https://web.archive.org/web/20111214093006/http://msds.chem.ox.ac.uk/ET/ethylene_glycol.html
| url-status = dead
}}</ref> The major danger is due to its sweet [[taste]], which can attract children and animals. Upon ingestion, ethylene glycol is oxidized to [[glycolic acid]], which is, in turn, oxidized to [[oxalic acid]], which is [[Toxicity|toxic]]. It and its toxic byproducts first affect the [[central nervous system]], then the heart, and finally the kidneys. Ingestion of sufficient amounts is fatal if untreated.<ref>[https://www.cdc.gov/niosh/ershdb/EmergencyResponseCard_29750031.html Ethylene glycol]. National Institute for Occupational Safety and Health. Emergency Response Database. August 22, 2008. Retrieved December 31, 2008.</ref> Several deaths are recorded annually in the U.S. alone.<ref>{{EMedicine|article|814701|Ethylene Glycol Toxicity}}</ref>

Antifreeze products for automotive use containing [[propylene glycol]] in place of ethylene glycol are available. They are generally considered safer to use, as propylene glycol is not as palatable{{refn|group=note|Pure propylene glycol does not taste bitter, and pure propylene glycol is often used as a food additive, for instance in cake icing and shelf-stable whipped cream. Industrial-grade propylene glycol usually has a slightly bitter or acrid taste due to impurities. See the article on [[propylene glycol]] for more information. The relative sweetness of ethylene glycol<ref>{{cite book|title=The Merck Index|date=2013|publisher=Royal Society of Chemistry|pages=M5122|edition=15th}}</ref> and propylene glycol<ref>{{cite book|title=The Merck Index|date=2013|publisher=Royal Society of Chemistry|pages=M9238|edition=15th}}</ref> is discussed in the Merck Index, and neither compound is described as bitter.}} and is converted in the body to [[lactic acid]], a normal product of metabolism and exercise.<ref>{{cite web |url=http://www.resteddoginn.ca/antifreeze.php |title=Ethylene Glycol Poisoning |author=Pieter Klapwijk |date=January 27, 2010 |publisher=The Rested Dog Inn |access-date=October 11, 2012 |archive-date=January 26, 2013 |archive-url=https://web.archive.org/web/20130126003300/http://www.resteddoginn.ca/antifreeze.php |url-status=dead }}</ref>

Australia, the UK, and seventeen US states (as of 2012) require the addition of a bitter flavoring ([[Denatonium|denatonium benzoate]]) to antifreeze. In December 2012, US antifreeze manufacturers agreed voluntarily to add a bitter flavoring to all antifreeze that is sold in the consumer market of the US.<ref>{{cite web|title=Antifreeze and Engine Coolant Being Bittered Nationwide|url=http://www.cspa.org/category/news-releases/2012/12/antifreeze-and-engine-coolant-being-bittered-nationwide/|publisher=Consumer Specialty Products Association|access-date=30 June 2016|archive-url=https://web.archive.org/web/20121228225407/http://www.cspa.org/news-media-center/news-releases/2012/12/antifreeze-and-engine-coolant-being-bittered-nationwide|archive-date=28 December 2012|date=13 December 2012}}</ref>

In 2022, several hundred children died of acute [[kidney failure]] in [[Indonesia]] and [[The Gambia]] because the [[paracetamol]] syrup made by [[New Delhi]]-based Maiden Pharmaceuticals contained ethylene glycol and [[diethylene glycol]], ingredients that have been linked to child deaths from [[acute kidney injury]] in The Gambia.<ref>{{cite news |title=Indonesia says child deaths from acute kidney injury rise to 133 |url=https://www.aljazeera.com/news/2022/10/22/indonesia-says-child-deaths-from-acute-kidney-injury-rise-to-133 |work=[[Al Jazeera Arabic|Al Jazeera]] |date=22 October 2022}}</ref> In December 2022, [[Uzbekistan]]'s health ministry has said children died as a result of ethylene glycol in [[Toxic cough syrup|cough syrup]] made by [[Marion Biotech]], which is based at [[Noida]], near New Delhi.<ref>{{cite news |url=https://www.bbc.co.uk/news/world-asia-india-64114240 |title=Marion Biotech: Uzbekistan links child deaths to India cough syrup |date=29 December 2022 |work=[[BBC News]] }}</ref>

==Environmental effects==

Ethylene glycol is a [[High production volume chemicals|high-production-volume chemical]]. It breaks down in air in about 10 days and in water or soil in a few weeks. It enters the environment through the dispersal of ethylene glycol-containing products, especially at airports, where it is used in [[de-icing]] agents for runways and airplanes.<ref>{{cite web|url = https://wwwn.cdc.gov/TSP/ToxFAQs/ToxFAQsDetails.aspx?faqid=85&toxid=21 |publisher = CDC|work = ToxFAQs|title = Ethylene Glycol|date = 12 March 2015}}</ref> While prolonged low doses of ethylene glycol show no toxicity, at near lethal doses (≥ 1000&nbsp;mg/kg per day) ethylene glycol acts as a [[teratogen]]. "Based on a rather extensive database, it induces skeletal variations and malformations in rats and mice by all routes of exposure."<ref name=HC>{{cite web|title=Statement of the Science Report for Ethylene Glycol|url=http://www.hc-sc.gc.ca/ewh-semt/pubs/contaminants/psl2-lsp2/ethylene_glycol/index-eng.php#a2436 |website=3.3.2.2 Non-neoplastic effects|publisher=Health Canada www.hc-sc.gc.ca|access-date=27 August 2014|date=June 24, 2013}}</ref>

== Notes ==
{{reflist|group=note}}

== References ==
{{reflist}}

== External links ==

* [http://webbook.nist.gov/cgi/cbook.cgi?ID=C107211 WebBook page for C2H6O2]
* [http://www.atsdr.cdc.gov/csem/egpg/index.html ATSDR - Case Studies in Environmental Medicine: Ethylene Glycol and Propylene Glycol Toxicity]
* [https://www.cdc.gov/niosh/npg/npgd0272.html CDC - NIOSH Pocket Guide to Chemical Hazards]
* [https://lcglad.dk/glycol/ Antifreeze ratio for Ethylene Glycol and Propylene Glycol]
* [http://www.emedicine.com/emerg/topic177.htm Medical information]
* {{cite journal |author1=Hairong Yue |author2=Yujun Zhao |author3=Xinbin Ma |author4=Jinlong Gong | title = Ethylene glycol: properties, synthesis, and applications | journal = Chemical Society Reviews | issue = 11 | year = 2012 | volume = 41 | pages = 4218–4244 | doi = 10.1039/C2CS15359A|pmid=22488259  }}

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