Glycerol: Difference between revisions - Wikipedia


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{{short description|Chemical compound widely used in food and pharmaceuticals}}{{Redirect|Glycerine|the song by Bush|Glycerine (song)}}{{Use dmy dates|date=SeptemberAugust 20202024}}

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Typical plant sources include [[soybeans]] or [[Arecaceae|palm]]. Animal-derived [[tallow]] is another source. Approximately 950,000 tons per year are produced in the United States and Europe; 350,000 tons of glycerol were produced per year in the U.S. alone from 2000 to 2004.<ref>{{cite web |title= A Glycerin Factor |author= Nilles, Dave |url= https://www.biodieselmagazine.com/article.jsp?article_id=377 |publisher= Biodiesel Magazine |year= 2005 |access-date= 21 February 2022 |archive-date= 8 November 2007 |archive-url= https://web.archive.org/web/20071108114027/http://www.biodieselmagazine.com/article.jsp?article_id=377 |url-status= live }}</ref> The [[Directive on the Promotion of the use of biofuels and other renewable fuels for transport|EU directive 2003/30/EC]] set a requirement that 5.75% of petroleum fuels were to be replaced with [[biofuel]] sources across all [[Member state of the European Union|member states]] by 2010. It was projected in 2006 that by 2020, production would be six times more than demand, creating an excess of glycerol as a byproduct of biofuel production.<ref name="Ullmann">{{cite encyclopedia |encyclopedia= Ullmann's Encyclopedia of Industrial Chemistry |last1= Christoph |first1= Ralf |last2= Schmidt |first2= Bernd |last3= Steinberner |first3= Udo |last4= Dilla |first4= Wolfgang |last5= Karinen |first5= Reetta |year= 2006 |doi= 10.1002/14356007.a12_477.pub2 |chapter= Glycerol |isbn= 3527306730}}</ref>

Glycerol from triglycerides is produced on a large scale, but the crude product is of variable quality, with a low selling price of as low as US$0.02–0.05 per kilogram in 2011.<ref>{{cite journal |last1 = San Kong |first1 = Pei |last2 = Kheireddine Aroua |first2 = Mohamed |last3 = Ashri Wan Daud |first3 = Wan Mohd |year = 2016 |title = Conversion of crude and pure glycerol into derivatives: A feasibility evaluation |journal = Renewable and Sustainable Energy Reviews |volume = 63 |pages = 533–555 |doi = 10.1016/j.rser.2016.05.054 |bibcode = 2016RSERv..63..533K }}</ref> It can be purified, but the process is expensive. Some glycerol is burned for energy, but its heat value is low.<ref>{{cite news |url= https://www.biodieselmagazine.com/articles/8137/clearing-the-way-for-byproduct-quality |work= Biodiesel Magazine |title= Clearing the way for byproduct quality: why quality for glycerin is just as important for biodiesel |author= Sims, Bryan |date= 25 October 2011 |access-date= 21 February 2022 |archive-date= 29 April 2021 |archive-url= https://web.archive.org/web/20210429154729/http://www.biodieselmagazine.com/articles/8137/clearing-the-way-for-byproduct-quality |url-status= live}}</ref>

Crude glycerol from the hydrolysis of triglycerides can be purified by treatment with [[activated carbon]] to remove organic impurities, alkali to remove unreacted glycerol esters, and [[ion exchange]] to remove salts. High purity glycerol (greater than 99.5%) is obtained by multi-step distillation; a [[vacuum chamber]] is necessary due to its high boiling point (290&nbsp;°C).<ref name=Ullmann/>

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Although usually not cost-effective because so much is produced from processing of fats, glycerol can be produced by various routes. During [[World War II]], synthetic glycerol processes became a national defense priorities because it is a precursor to [[nitroglycerine]]. Epichlorohydrin is the most important precursor. [[Chlorination reaction|chlorination]] of propylene gives [[allyl chloride]], which is oxidized with [[hypochlorite]] to [[dichlorohydrin]], which reacts with a strong base to give [[epichlorohydrin]]. Epichlorohydrin can be hydrolyzed to glycerol. [[Chlorine]]-free processes from propylene include the synthesis of glycerol from [[acrolein]] and [[propylene oxide]].<ref name="Ullmann" />

: [[File:Synthetic routes to glycerol.png|600px]]

==Applications==

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It is also recommended as an additive when using polyol sweeteners such as [[erythritol]] and [[xylitol]] which have a cooling effect, due to its heating effect in the mouth, if the cooling effect is not wanted.<ref>{{cite web |title= Functional Food Design Rules |author= Nikolov, Ivan |date= 20 April 2014 |url= https://www.ivannikolov.com/functional-food-design-rules-part-2/ |access-date= 21 February 2022 |archive-date= 30 April 2021 |archive-url= https://web.archive.org/web/20210430030741/https://ivannikolov.com/functional-food-design-rules-part-2/ |url-status= live }}</ref>

Excessive consumption by children can lead to glycerol intoxication.<ref>{{Cite web |last=Burrell |first=Chloe |date=2023-06-02 |title=Perth and Kinross parents warned as 'intoxicated' kids hospitalised by slushy drinks |url=https://www.thecourier.co.uk/fp/news/perth-kinross/4445065/perth-kinross-warning-slushy-drinks/ |access-date=2023-06-03 |website=The Courier |language=en-GB}}</ref> Symptoms of intoxication include [[hypoglycemia]], [[nausea]] and a loss of consciousness ([[Syncope (medicine)|syncope]]). While intoxication as a result of excessive glycerol consumption is rare and its symptoms generally mild, occasional reports of hospitalization have occurred.<ref>{{Cite web |title=Toddler 'turned grey and passed out' after drinking Slush Puppie |url=https://www.bbc.com/news/articles/c725pzqzdgno |access-date=2024-07-31|date=2024-07-31 |website=www.bbc.com |language=en-GB}}</ref> In the United Kingdom in August 2023, manufacturers of syrup used in slush ice drinks were advised to reduce the amount of glycerol in their formulations by the Food Standards Agency to reduce the risk of intoxication.<ref>{{Cite web |title='Not suitable for under-4s': New industry guidance issued on glycerol in slush-ice drinks |url=https://www.food.gov.uk/news-alerts/news/not-suitable-for-under-4s-new-industry-guidance-issued-on-glycerol-in-slush-ice-drinks |access-date=2023-08-11 |website=Food Standards Agency |language=en}}</ref>

===Medical, pharmaceutical and personal care applications===

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[[Nitration]] gives [[nitroglycerin]], an essential ingredient of various explosives such as [[dynamite]], [[gelignite]], and propellants like [[cordite]]. Nitroglycerin under the name glyceryl trinitrate (GTN) is commonly used to relieve [[angina pectoris]], taken in the form of [[sub-lingual]] tablets, patches, or as an [[aerosol]] spray.

Trifunctional [[polyether polyol]]s are produced from glycerol and [[propylene oxide]].

Oxidation of glycerol affords [[mesoxalic acid]].<ref name="ciri2">{{cite journal |last1 = Ciriminna |first1 = Rosaria |last2 = Pagliaro |first2 = Mario |year = 2003 |title = One-Pot Homogeneous and Heterogeneous Oxidation of Glycerol to Ketomalonic Acid Mediated by TEMPO |journal = Advanced Synthesis & Catalysis |volume = 345 |issue = 3 |pages = 383–388 |doi = 10.1002/adsc.200390043}}</ref> Dehydrating glycerol affords [[hydroxyacetone]].

Chlorination of glycerol gives the [[1-chloropropane-2,3-diol]]:

: {{chem2|HOCH(CH2OH)2 + HCl -> HOCH(CH2Cl)(CH2OH) + H2O}}

The same compound can be produced by hydrolysis of epichlorohydrin.<ref>{{cite journal |doi=10.1021/cr5004002 |title=Glycerol Ether Synthesis: A Bench Test for Green Chemistry Concepts and Technologies |date=2015 |last1=Sutter |first1=Marc |last2=Silva |first2=Eric Da |last3=Duguet |first3=Nicolas |last4=Raoul |first4=Yann |last5=Métay |first5=Estelle |last6=Lemaire |first6=Marc |journal=Chemical Reviews |volume=115 |issue=16 |pages=8609–8651 |pmid=26196761 |url=https://hal.archives-ouvertes.fr/hal-01312971/file/ChemRev_2015_115_8609-8651.pdf }}</ref>

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===Research on additional uses===

Research continues into potential [[value-added]] products of glycerol obtained from biodiesel production.<ref>{{cite journal |doi= 10.1002/ep.10225 |title= The glycerin glut: Options for the value-added conversion of crude glycerol resulting from biodiesel production |year= 2007 |last1= Johnson |first1= Duane T. |last2= Taconi |first2= Katherine A. |journal= Environmental Progress |volume= 26 |issue= 4 |pages= 338–348|bibcode= 2007EnvPr..26..338J }}</ref> Examples (aside from combustion of waste glycerol):

* [[Hydrogen]] [[gas]] production.<ref>{{cite journal |author1= Marshall, A. T. |author2 =Haverkamp, R. G. |title= Production of hydrogen by the electrochemical reforming of glycerol-water solutions in a PEM electrolysis cell |year= 2008 |journal= [[International Journal of Hydrogen Energy]] |volume= 33 |issue= 17 |pages= 4649–4654 |doi= 10.1016/j.ijhydene.2008.05.029|bibcode =2008IJHE...33.4649M }}</ref>

* [[Glycerine acetate]] is a potential fuel additive.<ref>{{cite journal |title= Acidic mesoporous silica for the acetylation of glycerol: Synthesis of bioadditives to petrol fuel |year= 2007 |journal= [[Energy & Fuels]] |volume= 21 |issue= 3 |pages= 1782–1791 |doi= 10.1021/ef060647q |last1= Melero |first1= Juan A. |last2= Van Grieken |first2= Rafael |last3= Morales |first3= Gabriel |last4= Paniagua |first4= Marta}}</ref>

* Additive for [[starch]] thermoplastic.<ref>{{Cite journal|last1=Özeren|first1=Hüsamettin D.|last2=Olsson|first2=Richard T.|last3=Nilsson|first3=Fritjof|last4=Hedenqvist|first4=Mikael S. |date=2020-02-01|title=Prediction of plasticization in a real biopolymer system (starch) using molecular dynamics simulations |journal=Materials & Design |language=en |volume=187|pages=108387|doi=10.1016/j.matdes.2019.108387|issn=0264-1275|doi-access=free}}</ref><ref>{{Cite journal|last1=Özeren|first1=Hüsamettin Deniz|last2=Guivier|first2=Manon|last3=Olsson|first3=Richard T.|last4=Nilsson|first4=Fritjof|last5=Hedenqvist|first5=Mikael S. |date=2020-04-07|title=Ranking Plasticizers for Polymers with Atomistic Simulations; PVT, Mechanical Properties and the Role of Hydrogen Bonding in Thermoplastic Starch |journal=ACS Applied Polymer Materials |volume=2|issue=5|pages=2016–2026|doi=10.1021/acsapm.0c00191|doi-access=free}}</ref>

* Conversion to various other chemicals:

** [[Propylene glycol]]<ref>{{cite press release |title= Dow achieves another major milestone in its quest for sustainable chemistries |date= 15 March 2007 |publisher= [[Dow Chemical Company]] |url= https://www.dow.com/propyleneglycol/news/20070315b.htm |access-date= 13 July 2007 |archive-url= https://web.archive.org/web/20090916061724/https://www.dow.com/propyleneglycol/news/20070315b.htm |archive-date= 16 September 2009 |url-status= dead }}</ref>

** [[Acrolein]]<ref>{{cite journal |doi= 10.1039/b506285c |title= The catalytic dehydration of glycerol in sub- and supercritical water: a new chemical process for acrolein production |journal= [[Green Chemistry (journal)|Green Chemistry]] |volume= 8 |issue= 2 |pages= 214–220 |year= 2006 |last1= Ott |first1= L. |last2= Bicker |first2= M. |last3= Vogel |first3= H.}}</ref><ref>{{cite journal |title= Acrolein synthesis from glycerol in hot-compressed water |journal= [[Bioresource Technology]] |year= 2007 |volume= 98 |pages= 1285–1290 |doi= 10.1016/j.biortech.2006.05.007 |pmid= 16797980 |issue= 6 |last1= Watanabe |first1= Masaru |last2= Iida |first2= Toru |last3= Aizawa |first3= Yuichi |last4= Aida |first4= Taku M. |last5= Inomata |first5= Hiroshi|bibcode= 2007BiTec..98.1285W }}</ref><ref>{{Cite journal |last1=Abdullah |first1=Anas |last2=Zuhairi Abdullah |first2=Ahmad |last3=Ahmed |first3=Mukhtar |last4=Khan |first4=Junaid |last5=Shahadat |first5=Mohammad |last6=Umar |first6=Khalid |last7=Alim |first7=Md Abdul |date=March 2022 |title=A review on recent developments and progress in sustainable acrolein production through catalytic dehydration of bio-renewable glycerol |url=https://linkinghub.elsevier.com/retrieve/pii/S0959652622005145 |journal=Journal of Cleaner Production |language=en |volume=341 |pages=130876 |doi=10.1016/j.jclepro.2022.130876|bibcode=2022JCPro.34130876A |s2cid=246853148 }}</ref>

** [[Ethanol]]<ref name="Yazdani">{{cite journal |author1= Yazdani, S. S. |author2 =Gonzalez, R. |title= Anaerobic fermentation of glycerol: a path to economic viability for the biofuels industry |year= 2007 |journal= [[Current Opinion in Biotechnology]] |volume= 18 |issue= 3 |pages= 213–219 |doi= 10.1016/j.copbio.2007.05.002 |pmid= 17532205}}</ref><ref>{{cite press release |date=27 June 2007 |title=Engineers Find Way To Make Ethanol, Valuable Chemicals From Waste Glycerin |website=ScienceDaily |url=https://www.sciencedaily.com/releases/2007/06/070626115246.htm}}</ref>

** [[Epichlorohydrin]],<ref>{{cite press release |publisher= [[Dow Chemical Company]] |url= https://epoxy.dow.com/epoxy/news/2007/20070326b.htm |title= Dow Epoxy advances glycerine-to-epichlorohydrin and liquid epoxy resins projects by choosing Shanghai site |date= 26 March 2007 |access-date= 21 February 2022 |archive-date= 8 December 2011 |archive-url= https://web.archive.org/web/20111208095306/http://epoxy.dow.com/epoxy/news/2007/20070326b.htm |url-status= live }}</ref> a raw material for [[epoxy resins]]

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</div>

The enzyme [[glycerol kinase]] is present mainly in the liver and kidneys, but also in other body tissues, including muscle and brain.<ref>{{cite journal |pmc=1163884|pmid=183753|year=1976|last1=Tildon|first1=J. T.|title=Mitochondrial glycerol kinase activity in rat brain|journal=The Biochemical Journal|volume=157|issue=2|pages=513–516|last2=Stevenson|first2=J. H. Jr.|last3=Ozand|first3=P. T.|doi=10.1042/bj1570513}}</ref><ref>{{cite journal |title=Glycerol kinase activities in muscles from vertebrates and invertebrates|pmid=5801671 |pmc= 1187734 |volume=112|issue=4|date=May 1969|journal=Biochem. J.|pages=465–474|last1=Newsholme|first1=E. A.|last2=Taylor|first2=K|doi=10.1042/bj1120465}}</ref><ref>{{cite journal |vauthors= Jenkins, BT, Hajra, AK |date= 1976 |title= Glycerol Kinase and Dihydroxyacetone Kinase in Rat Brain |journal= Journal of Neurochemistry |volume= 26 |issue= 2 |pages= 377–385 |doi= 10.1111/j.1471-4159.1976.tb04491.x |pmid= 3631 |hdl= 2027.42/65297 |s2cid= 14965948 |url= https://deepblue.lib.umich.edu/bitstream/2027.42/65297/1/j.1471-4159.1976.tb04491.x.pdf |hdl-access= free |access-date= 27 August 2019 |archive-date= 21 February 2022 |archive-url= https://web.archive.org/web/20220221143240/https://deepblue.lib.umich.edu/bitstream/handle/2027.42/65297/j.1471-4159.1976.tb04491.x.pdf;jsessionid=27E5DB761F19C9F26C4F8EF4EDC33819?sequence=1 |url-status= live }}</ref> In adipose tissue, glycerol 3-phosphate is obtained from [[dihydroxyacetone phosphate]] with the enzyme [[glycerol-3-phosphate dehydrogenase]].

==Toxicity and safety==

Glycerol has very low toxicity when ingested; its [[LD50|LD<sub>50</sub>]] oral dose for rats is 12600&nbsp;mg/kg and 8700&nbsp;mg/kg for mice. It does not appear to cause toxicity when inhaled, although changes in cell maturity occurred in small sections of lung in animals under the highest dose measured. A sub-chronic 90-day nose-only inhalation study in Sprague–Dawley (SD) rats exposed to 0.03, 0.16 and 0.66&nbsp;mg/L glycerin (Per liter of air) for 6-hour continuous sessions revealed no treatment-related toxicity other than minimal [[metaplasia]] of the [[epithelium]] lining at the base of the [[epiglottis]] in rats exposed to 0.66&nbsp;mg/L glycerin.<ref>{{cite journal | year = 2017 | title = Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague–Dawley rats in a 90-day OECD inhalation study complemented by molecular endpoints | journal = Food and Chemical Toxicology | volume = 109 | issue = Pt 1| pages = 315–332 | doi = 10.1016/j.fct.2017.09.001 | last1 = Phillips | first1 = Blaine | last2 = Titz | first2 = Bjoern | last3 = Kogel | first3 = Ulrike | last4 = Sharma | first4 = Danilal | last5 = Leroy | first5 = Patrice | last6 = Xiang | first6 = Yang | last7 = Vuillaume | first7 = Grégory | last8 = Lebrun | first8 = Stefan | last9 = Sciuscio | first9 = Davide | last10 = Ho | first10 = Jenny | last11 = Nury | first11 = Catherine | last12 = Guedj | first12 = Emmanuel | last13 = Elamin | first13 = Ashraf | last14 = Esposito | first14 = Marco | last15 = Krishnan | first15 = Subash | last16 = Schlage | first16 = Walter K. | last17 = Veljkovic | first17 = Emilija | last18 = Ivanov | first18 = Nikolai V. | last19 = Martin | first19 = Florian | last20 = Peitsch | first20 = Manuel C. | last21 = Hoeng | first21 = Julia | last22 = Vanscheeuwijck | first22 = Patrick| pmid = 28882640 | doi-access = free }}</ref><ref>{{cite journal | last1 = Renne | first1 = R. A. | last2 = Wehner | first2 = A. P. | last3 = Greenspan | first3 = B. J. | last4 = Deford | first4 = H. S. | last5 = Ragan | first5 = H. A. | last6 = Westerberg | first6 = R. B. | year = 1992 | title = 2-Week and 13-Week Inhalation Studies of Aerosolized Glycerol in Rats | journal = International Forum for Respiratory Research | volume = 4 | issue = 2| pages = 95–111 | doi = 10.3109/08958379209145307| bibcode = 1992InhTx...4...95R }}</ref>

===Glycerol intoxication===

Excessive consumption by children can lead to glycerol intoxication.<ref>{{Cite web |last=Burrell |first=Chloe |date=2023-06-02 |title=Perth and Kinross parents warned as 'intoxicated' kids hospitalised by slushy drinks |url=https://www.thecourier.co.uk/fp/news/perth-kinross/4445065/perth-kinross-warning-slushy-drinks/ |access-date=2023-06-03 |website=The Courier |language=en-GB}}</ref> Symptoms of intoxication include [[hypoglycemia]], [[nausea]] and a loss of consciousness ([[Syncope (medicine)|syncopeloss of consciousness]]). While intoxication as a result of excessive glycerol consumption is rare and its symptoms generally mild, occasional reports of hospitalization have occurred.<ref>{{Cite web |title=Toddler 'turned grey and passed out' after drinking Slush Puppie |url=https://www.bbc.com/news/articles/c725pzqzdgno |access-date=2024-07-31|date=2024-07-31 |website=www.bbc.com |language=en-GB}}</ref> In the United Kingdom in August 2023, manufacturers of syrup used in [[slushy|slush ice drinksdrink]]s were advised to reduce the amount of glycerol in their formulations by the Food Standards Agency to reduce the risk of intoxication.<ref>{{Cite web |title='Not suitable for under-4s': New industry guidance issued on glycerol in slush-ice drinks |url=https://www.food.gov.uk/news-alerts/news/not-suitable-for-under-4s-new-industry-guidance-issued-on-glycerol-in-slush-ice-drinks |access-date=2023-08-11 |website=Food Standards Agency |language=en}}</ref>

[[Food Standards Scotland]] advises that slush ice drinks containing glycerol should not be given to children under the age of 4, owing to the risk of intoxication. It also recommends that businesses do not use [[free refill]] offers for the drinks in venues where children under the age of 10 are likely to consume them, and that products should be appropriately labelled to inform consumers of the presence of glycerol.<ref>{{Cite web |title=Glycerol in slush ice drinks {{!}} Food Standards Scotland |url=https://www.foodstandards.gov.scot/consumers/food-safety/buying-food-eating-out/glycerol-in-slush-ice-drinks |access-date=2024-08-04 |website=www.foodstandards.gov.scot}}</ref>

Glycerol has very low toxicity when ingested; its [[LD50|LD<sub>50</sub>]] oral dose for rats is 12600&nbsp;mg/kg and 8700&nbsp;mg/kg for mice. It does not appear to cause toxicity when inhaled, although changes in cell maturity occurred in small sections of lung in animals under the highest dose measured. A sub-chronic 90-day nose-only inhalation study in Sprague–Dawley (SD) rats exposed to 0.03, 0.16 and 0.66&nbsp;mg/L glycerin (Per liter of air) for 6-hour continuous sessions revealed no treatment-related toxicity other than minimal [[metaplasia]] of the [[epithelium]] lining at the base of the [[epiglottis]] in rats exposed to 0.66&nbsp;mg/L glycerin.<ref>{{cite journal | year = 2017 | title = Toxicity of the main electronic cigarette components, propylene glycol, glycerin, and nicotine, in Sprague–Dawley rats in a 90-day OECD inhalation study complemented by molecular endpoints | journal = Food and Chemical Toxicology | volume = 109 | issue = Pt 1| pages = 315–332 | doi = 10.1016/j.fct.2017.09.001 | last1 = Phillips | first1 = Blaine | last2 = Titz | first2 = Bjoern | last3 = Kogel | first3 = Ulrike | last4 = Sharma | first4 = Danilal | last5 = Leroy | first5 = Patrice | last6 = Xiang | first6 = Yang | last7 = Vuillaume | first7 = Grégory | last8 = Lebrun | first8 = Stefan | last9 = Sciuscio | first9 = Davide | last10 = Ho | first10 = Jenny | last11 = Nury | first11 = Catherine | last12 = Guedj | first12 = Emmanuel | last13 = Elamin | first13 = Ashraf | last14 = Esposito | first14 = Marco | last15 = Krishnan | first15 = Subash | last16 = Schlage | first16 = Walter K. | last17 = Veljkovic | first17 = Emilija | last18 = Ivanov | first18 = Nikolai V. | last19 = Martin | first19 = Florian | last20 = Peitsch | first20 = Manuel C. | last21 = Hoeng | first21 = Julia | last22 = Vanscheeuwijck | first22 = Patrick| pmid = 28882640 | doi-access = free }}</ref><ref>{{cite journal | last1 = Renne | first1 = R. A. | last2 = Wehner | first2 = A. P. | last3 = Greenspan | first3 = B. J. | last4 = Deford | first4 = H. S. | last5 = Ragan | first5 = H. A. | last6 = Westerberg | first6 = R. B. | year = 1992 | title = 2-Week and 13-Week Inhalation Studies of Aerosolized Glycerol in Rats | journal = International Forum for Respiratory Research | volume = 4 | issue = 2| pages = 95–111 | doi = 10.3109/08958379209145307}}</ref>

==Historical cases of contamination with diethylene glycol==

On 4 May 2007, the FDA advised all U.S. makers of medicines to test all batches of glycerol for [[diethylene glycol]] contamination.<ref>{{cite web |publisher= U.S. Food and Drug Administration |url= https://www.fda.gov/bbs/topics/NEWS/2007/NEW01628.html |title= FDA Advises Manufacturers to Test Glycerin for Possible Contamination |date= 4 May 2007 |access-date= 8 May 2007 |archive-date= 7 May 2007 |archive-url= https://web.archive.org/web/20070507074219/http://www.fda.gov/bbs/topics/NEWS/2007/NEW01628.html |url-status= live}}</ref> This followed an occurrence of [[Toxic cough syrup|hundreds of fatal poisonings in Panama]] resulting from a falsified import customs declaration by Panamanian import/export firm Aduanas Javier de Gracia Express, S. A. The cheaper diethylene glycol was relabeled as the more expensive glycerol.<ref>{{cite news |author= Walt Bogdanich |date= 6 May 2007 |url= https://www.nytimes.com/2007/05/06/world/06poison.html |title= From China to Panama, a Trail of Poisoned Medicine |work= The New York Times |access-date= 8 May 2007 |author-link= Walt Bogdanich |archive-date= 26 September 2015 |archive-url= https://web.archive.org/web/20150926084342/http://www.nytimes.com/2007/05/06/world/06poison.html |url-status= live }}</ref><ref>{{cite news |date= 20 February 2013 |url= https://www.topmastersinpublichealth.com/10-biggest-medical-scandals-in-history |title= 10 Biggest Medical Scandals in History |access-date= 21 February 2022 |archive-date= 8 January 2022 |archive-url= https://web.archive.org/web/20220108074814/https://www.topmastersinpublichealth.com/10-biggest-medical-scandals-in-history/ |url-status= live }}</ref> Between 1990 and 1998, incidents of DEG poisoning reportedly occurred in Argentina, Bangladesh, India, and Nigeria, and resulted in hundreds of deaths. In 1937, more than one hundred people died in the United States after ingesting DEG-contaminated elixir sulfanilamide, a drug used to treat infections.<ref>{{Cite journal|last=Lang|first=Les|date=2007-07-01|title=FDA Issues Statement on Diethylene Glycol and Melamine Food Contamination|url=https://www.gastrojournal.org/article/S0016-5085(07)00995-X/abstract|journal=Gastroenterology|language=en|volume=133|issue=1|pages=5–6|doi=10.1053/j.gastro.2007.05.013|pmid=17631118|issn=0016-5085|access-date=25 December 2020|archive-date=21 February 2022|archive-url=https://web.archive.org/web/20220221143257/https://www.gastrojournal.org/article/S0016-5085%2807%2900995-X/fulltext|url-status=live|doi-access=free}}</ref>

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==Properties==

Table of thermal and physical properties of saturated liquid glycerin:<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 |last=Incropera 1 Dewitt 2 Bergman 3 Lavigne 4 |first=Frank P. 1 David P. 2 Theodore L. 3 Adrienne S. 4 |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 mw-collapsed"

!Temperature (°C)

![[Density]] (kg/m<sup>3</sup>)