Editing Castor oil (section)

==Industrial uses==

===Coatings===
Castor oil is used as a biobased [[polyol]] in the [[polyurethane]] industry. The average functionality (number of [[hydroxyl]] groups per triglyceride molecule) of castor oil is 2.7, so it is widely used as a rigid polyol and in coatings.<ref name=ullmanns/> 
One particular use is in a polyurethane concrete where a castor-oil emulsion is reacted with an isocyanate (usually polymeric [[methylene diphenyl diisocyanate]]) and a [[cement]] and [[construction aggregate]]. This is applied fairly thickly as a slurry, which is self-levelling. This base is usually further coated with other systems to build a resilient floor.<ref>{{Cite journal|last=Howarth|first=GA|date=June 2003|title=Polyurethanes, polyurethane dispersions and polyureas: Past, present and future|journal=Surface Coatings International Part B: Coatings Transactions|language=en|volume=86|issue=2|pages=111–118|doi=10.1007/bf02699621|s2cid=93574741|issn=1476-4865}}</ref> Castor oil is not a [[drying oil]], meaning that it has a low reactivity with air compared with oils such as [[linseed oil]] and [[tung oil]]. However, dehydration of castor oil yields linoleic acids, which do have drying properties.<ref name=ullmanns/> 
In this process, the OH group on the ricinoleic acid along with a hydrogen from the next carbon atom are removed, forming a double bond which then has oxidative cross-linking properties and yields the drying oil. It is considered a vital raw material.<ref>{{Cite journal |last=Ogunniyi |first=D. S. |date=2006-06-01 |title=Castor oil: A vital industrial raw material |url=https://www.sciencedirect.com/science/article/pii/S0960852405002026 |journal=Bioresource Technology |language=en |volume=97 |issue=9 |pages=1086–1091 |doi=10.1016/j.biortech.2005.03.028 |pmid=15919203 |bibcode=2006BiTec..97.1086O |issn=0960-8524 |access-date=2023-03-09 |archive-date=2016-11-30 |archive-url=https://web.archive.org/web/20161130045802/http://www.sciencedirect.com/science/article/pii/S0960852405002026 |url-status=live }}</ref>

===Chemical precursor===
Castor oil can react with other materials to produce other chemical compounds that have numerous applications.<ref>{{Cite journal |last1=Ma |first1=Yufeng |last2=Wang |first2=Rui |last3=Li |first3=Qiaoguang |last4=Li |first4=Mei |last5=Liu |first5=Chengguo |last6=Jia |first6=Puyou |date=2021-03-24 |title=Castor oil as a platform for preparing bio-based chemicals and polymer materials |url=https://www.icevirtuallibrary.com/doi/10.1680/jgrma.20.00085 |journal=Green Materials |volume=10 |issue=3 |pages=99–109 |doi=10.1680/jgrma.20.00085 |s2cid=233687152 |issn=2049-1220 |access-date=2022-04-18 |archive-date=2023-01-31 |archive-url=https://web.archive.org/web/20230131222012/https://www.icevirtuallibrary.com/doi/10.1680/jgrma.20.00085 |url-status=live }}</ref><ref name="uses">{{cite web|url=http://whc-oils.com/castor-oil.html|title=Multiple uses of castor oil|access-date=2007-08-02|archive-date=2007-09-29|archive-url=https://web.archive.org/web/20070929062813/http://whc-oils.com/castor-oil.html|url-status=dead}}</ref><ref>{{cite journal|title=Castor oil as a renewable resource for the chemical industry |date=2010-01-25 |doi=10.1002/ejlt.200900138 |volume=112 |journal=European Journal of Lipid Science and Technology |pages=10–30|last1 = Mutlu|first1 = Hatice|last2=Meier |first2=Michael A. R. }}</ref><ref>{{Cite journal|last=Ogunniyi |first=D.S. |date=June 2006 |title=Castor oil: A vital industrial raw material |journal=Bioresource Technology |volume=97 |issue=9 |pages=1086–91 |doi=10.1016/j.biortech.2005.03.028 |pmid=15919203 |bibcode=2006BiTec..97.1086O }}</ref> 
[[Transesterification]] followed by [[steam cracking]] gives [[undecylenic acid]], a precursor to specialized polymer [[nylon 11]], and [[heptanal]], a component in fragrances.<ref>Ashford's Dictionary of Industrial Chemicals, Third edition, 2011, page 6162</ref> 
Breakdown of castor oil in strong base gives [[2-Octanol|2-octanol]], both a fragrance component and a specialized solvent, and the [[dicarboxylic acid]] [[sebacic acid]]. Hydrogenation of castor oil saturates the alkenes, giving a waxy lubricant.<ref name=ullmanns/> 
Castor oil may be epoxidized by reacting the OH groups with [[epichlorohydrin]] to make the [[Castor oil glycidyl ether|triglycidyl ether of castor oil]] which is useful in epoxy technology.<ref>{{Cite book|url=https://books.google.com/books?id=XiRdDgAAQBAJ&q=Heloxy+505&pg=PA157|title=Polymeric Thermosetting Compounds: Innovative Aspects of Their Formulation Technology|last=Hermansen|first=Ralph D.|date=2017-03-16|publisher=CRC Press|isbn=9781771883153|language=en|access-date=2020-11-09|archive-date=2023-01-14|archive-url=https://web.archive.org/web/20230114165300/https://books.google.com/books?id=XiRdDgAAQBAJ&q=Heloxy+505&pg=PA157|url-status=live}}</ref> 
This is available commercially as Heloxy 505.<ref>{{cite book |last1=Ash |first1=Michael |last2=Ash |first2=Irene |title=Handbook of fillers, extenders, and diluents |publisher=Synapse Information Resources |location=Endicott, NY |isbn=9781890595968 |page=82 |edition=2nd|year=2007 }}</ref>

The production of [[Lithium soap#Lithium grease|lithium grease]] consumes a significant amount of castor oil. [[Hydrogenation]] and [[saponification]] of castor oil yields 12-hydroxystearic acid, which is then reacted with [[lithium hydroxide]] or [[lithium carbonate]] to give high-performance lubricant grease.<ref>{{Cite book|title=Kirk-Othmer Encyclopedia of Chemical Technology |url=https://www.scribd.com/doc/30116043/Castor-Oil |access-date=2010-07-12 |url-status=dead |archive-url=https://web.archive.org/web/20110714101239/http://www.scribd.com/doc/30116043/Castor-Oil |archive-date=July 14, 2011 }}</ref>

Since it has a relatively high [[dielectric constant]] (4.7), highly refined and dried castor oil is sometimes used as a [[dielectric fluid]] within high-performance, high-voltage [[capacitor]]s.

===Lubrication===
[[File:Advertisement from The Aerial Age Weekly in 1921 - 002.jpg|thumb|Castor oil advertisement from ''The Aerial Age Weekly'' in 1921]]
Vegetable oils such as castor oil are typically unattractive alternatives to [[petroleum]]-derived [[lubricants]] because of their poor [[oxidation|oxidative]] stability.<ref>{{cite web |url= http://www.ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=166442 |title=Directed synthesis of base oils that overcome traditional vegetable oil shortcomings|author-first1=Terry|author-last1=Isbell|publisher=Society of Tribologists and Lubrication Engineers|date=May 20, 2004|access-date= 2007-08-02 |archive-date= 2006-10-01 |archive-url= https://web.archive.org/web/20061001013304/http://ars.usda.gov/research/publications/publications.htm?SEQ_NO_115=166442 |url-status= live }}</ref><ref>{{cite web |url= http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/oil.html#Environment |title= Petroleum Oil and the Environment |publisher= DOE |access-date= 2006-12-28 |archive-date= 2009-08-23 |archive-url= https://web.archive.org/web/20090823080443/http://www.eia.doe.gov/kids/energyfacts/sources/non-renewable/oil.html#Environment |url-status= live }}</ref> Castor oil has better low-temperature [[viscosity]] properties and high-temperature lubrication than most vegetable oils, making it useful as a lubricant in [[Jet engine|jet]], [[Diesel engine|diesel]], and racing engines.<ref>{{cite web|last=McGuire |first=Nancy |title=Taming the Bean |publisher=The American Chemical Society |year=2004 |url=http://www.chemistry.org/portal/a/c/s/1/feature_pro.html?id=c373e9faf603d46b8f6a4fd8fe800100 |access-date=2007-08-02 |url-status=dead |archive-url=https://web.archive.org/web/20060927062935/http://www.chemistry.org/portal/a/c/s/1/feature_pro.html?id=c373e9faf603d46b8f6a4fd8fe800100 |archive-date=September 27, 2006 }}</ref> The viscosity of castor oil at 10&nbsp;°C is 2,420 [[centipoise]],<ref name=Mat_hand>{{cite book |last1= Brady |first1= George S. |title= Materials Handbook |year= 1997 |publisher= McGraw-Hill |location= New York |isbn= 978-0070070844 |edition= 14th |last2= Clauser |first2= Henry R. |last3= Vaccari |first3= John |url-access= registration |url= https://archive.org/details/materialshandboo14geor }}</ref> but it tends to form gums in a short time, so its usefulness is limited to engines that are regularly rebuilt, such as racing engines. Lubricant company [[Castrol]] took its name from castor oil.

Castor oil has been suggested as a lubricant for [[bicycle pump]]s because it does not degrade natural rubber seals.<ref>{{Cite book |last= Older |first= Jules |title= Backroad and Offroad Biking |publisher= Stackpole Books |location= Mechanicsburg, PA |year= 2000 |page= 37 |isbn= 978-0811731508}}</ref>

====Turkey red oil====
Turkey red oil, also called sulphonated (or sulfated) castor oil, is made by adding [[sulfuric acid]] to vegetable oils, most notably castor oil.<ref name=HP/> It was the first synthetic [[detergent]] after ordinary [[soap]]. It is used in formulating [[lubricant]]s, softeners, and [[dye|dyeing assistants]].<ref name=HP>{{cite book |last1=Penda |first1=H |title=Herbal Soaps & Detergents Handbook |date=2017 |publisher=NIIR |location=Delhi, India |isbn=9789381039007 |page=121}}</ref>

====Biodiesel====
Castor oil, like currently less expensive vegetable oils, can be used as feedstock in the production of [[biodiesel]]. The resulting fuel is superior for cold winters, because of its exceptionally low [[cloud point]] and [[pour point]].<ref>''Biodiesel from Castor Oil: A Promising Fuel for Cold Weather'' [http://www.icrepq.com/full-paper-icrep/222-barajas.pdf (PDF)] {{webarchive |url=https://web.archive.org/web/20130616073236/http://www.icrepq.com/full-paper-icrep/222-barajas.pdf |date=June 16, 2013 }} by Carmen Leonor Barajas Forero, 2004-10-12. Retrieved 2012-01-24.</ref>

Initiatives to grow more castor for energy production, in preference to other oil crops, are motivated by social considerations. Tropical subsistence farmers would gain a [[cash crop]].<ref>[http://www.biodieselmagazine.com/articles/622/the-promise-of-the-castor-bean ''The Promise of the Castor Bean''] {{webarchive |url=https://web.archive.org/web/20160309162746/http://www.biodieselmagazine.com/articles/622/the-promise-of-the-castor-bean |date=March 9, 2016 }} by Elizabeth Johnson, Biodiesel Magazine, 2004-12-01. Retrieved 2012-01-24.</ref>

===Early aviation and aeromodelling===
[[File:Le Rhone 9C.jpg|thumb|right|World War I aviation [[rotary engines]] used castor oil as a primary lubricant, mixed with the fuel]] 
Castor oil was the preferred lubricant for [[rotary engines]], such as the [[Gnome et Rhône|Gnome engine]] after that engine's widespread adoption for aviation in Europe in 1909. It was used almost universally in rotary-engined Allied aircraft in [[World War I]]. Germany had to make do with inferior ''[[ersatz]]'' oil for its rotary engines, which resulted in poor reliability.<ref>{{cite book |last= Guilmartin |first= John F. Jr. |title= Two Historians in Technology and War |year= 1994 |publisher= United States Army War College, Strategic Studies Institute |isbn= 978-1428915220 |page= 10 |chapter= Technology and Strategy: What Are the Limits?}}</ref><ref>{{cite book |last= Fisher |first= Suzanne Hayes |title= The European Powers in the First World War: An Encyclopedia |year= 1999 |publisher= Taylor & Francis |isbn= 978-0815333517 |page= 10 |chapter= Aircraft, production during the war |editor-first1= Spencer C. |editor-last1= Tucker |editor-first2= Laura Matysek |editor-last2= Wood |editor-first3= Justin D. |editor-last3= Murphy }}</ref><ref>{{cite book |title= Tariff Information Surveys on the Articles in Paragraphs 44 and 45 of the Tariff Act of 1913 |year= 1921 |author= U.S. Tariff Commission |page=40 |publisher= Government Printing Office |location= Washington, D.C. |author-link= United States Tariff Commission }}</ref>

The [[methanol]]-fueled, two-cycle, [[Glow plug (model engine)|glow-plug engines]] used for aeromodelling, since their adoption by [[model airplane]] hobbyists in the 1940s, have used varying percentages of castor oil as lubricants. It is highly resistant to degradation when the engine has its fuel-air mixture leaned for maximum engine speed. Gummy residues can still be a problem for aeromodelling powerplants lubricated with castor oil, however, usually requiring eventual replacement of [[ball bearing]]s when the residue accumulates within the engine's bearing races. One British manufacturer of [[sleeve valve]]d four-cycle model engines has stated the "varnish" created{{fact|date=January 2025}}<!-- many classical sources talk about the absence of film --> by using castor oil in small percentages can improve the pneumatic seal of the sleeve valve, improving such an engine's performance over time.