Editing Paraffin wax

{{short description|Soft colorless solid derived from petroleum, coal or shale oil}}
{{about|the wax|the fuel|kerosene}}
{{Use dmy dates|date=March 2019}}
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| Formula = C<sub>n</sub>H<sub>2n+2</sub>
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| Appearance = White solid<ref name=GESTIS>{{GESTIS|ZVG=92540}}</ref>
| Odor = Odorless
| BoilingPt = > {{convert|370|C}}
| Solubility = ~1 mg/L<ref name=GESTIS/>
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[[File:Candle black.jpg|thumb|100px|Paraffin candle]]

'''Paraffin wax''' (or '''petroleum wax''') is a soft colorless solid derived from [[petroleum]], [[coal]], or [[oil shale]] that consists of a mixture of [[hydrocarbon]] molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and [[melting point|begins to melt]] above approximately {{convert|37|°C|°F}},<ref name="PF">{{cite book |last1=Freund |first1=Mihály |last2=Mózes |first2=Gyula |translator=Jakab, E. |title=Paraffin products: properties, technologies, applications |year=1982 |publisher=Elsevier |location=Amsterdam, the Netherlands |isbn=978-0-444-99712-8 |page=121 }}</ref> and its boiling point is above {{convert|370|°C|°F}}.<ref name="PF"/> Common applications for paraffin wax include [[lubrication]], [[electrical insulation]], and [[candles]];<ref>[http://europecandles.org/pages/uk/an-everlasting-history/raw-materials-and-candles-production-processes.php Raw materials and candles production processes] {{Webarchive|url=https://web.archive.org/web/20200321103525/https://europecandles.org/raw-materials-and-candles-production-processes |date=21 March 2020 }}, AECM</ref> dyed paraffin wax can be made into [[crayon]]s.

Un-dyed, unscented paraffin candles are odorless and bluish-white. Paraffin wax was first created by [[Carl Reichenbach#Scientific contributions|Carl Reichenbach]] in Germany in 1830 and marked a major advancement in candlemaking technology, as it burned more cleanly and reliably than [[tallow]] candles and was cheaper to produce.<ref name="auto">{{cite web|title=History of Candles|url=http://candles.org/history/|website=National Candle Association|access-date=25 February 2016}}</ref>

In chemistry, ''paraffin'' is used synonymously with ''[[alkane]]'', indicating hydrocarbons with the general formula C<sub>''n''</sub>H<sub>2''n''+2</sub>. The name is derived from [[Latin]] ''parum'' ("very little") + ''affinis'', meaning "lacking [[electron affinity|affinity]]" or "lacking [[reactivity (chemistry)|reactivity]]", referring to paraffin's unreactive nature.<ref>{{cite book |title=Oxford English Dictionary |publisher=Oxford University Press |location=Oxford, England |date=March 2009 |chapter=Paraffin, n|title-link=Oxford English Dictionary }}</ref>

== Properties ==
Paraffin [[wax]] is mostly found as a white, odorless, flavourless, waxy solid, with a typical melting point between about {{convert|46|and|68|°C|°F}},<ref>{{cite book|last=Nasser|first=William E|editor=McKetta, John J|title=Encyclopedia of Chemical Processing and Design|volume=67|year=1999|publisher=Marcel Dekker|location=New York|isbn=978-0-8247-2618-8|page=17|chapter=Waxes, Natural and Synthetic}} This can vary widely, even outside the quoted range, according to such factors as oil content and crystalline structure.</ref> and a density of around 900&nbsp;kg/m<sup>3</sup>.<ref name=kayelabymech>{{cite web
| last =Kaye
| first =George William Clarkson
| author2 =Laby, Thomas Howell
| author-link2 =T. H. Laby
| title =Mechanical properties of materials
| work =Kaye and Laby Tables of Physical and Chemical Constants
| publisher =[[National Physical Laboratory, UK|National Physical Laboratory]]
| url =http://www.kayelaby.npl.co.uk/general_physics/2_2/2_2_1.html
| access-date =25 October 2013
| archive-url =https://web.archive.org/web/20080311173419/http://www.kayelaby.npl.co.uk/general_physics/2_2/2_2_1.html
| archive-date =11 March 2008
| url-status =dead
}}</ref> It is insoluble in water, but soluble in [[diethyl ether|ether]], [[benzene]], and certain [[ester]]s. Paraffin is unaffected by most common chemical [[reagent]]s but [[combustion|burns]] readily.<ref>{{cite book|last1=Seager|first1=Spencer L.|last2=Slabaugh|first2=Michael|title=Chemistry for Today: General, Organic, and Biochemistry|publisher=Cengage|location=Belmont, California|isbn=978-0-538-73332-8|page=364|chapter=Alkane reactions|date=19 January 2010}}</ref> Its heat of combustion is 42 MJ/kg.<ref>{{Cite journal|last=Wiener|first=Harry|date=January 1947|title=Structural Determination of Paraffin Boiling Points|url=https://pubs.acs.org/doi/pdf/10.1021/ja01193a005|journal=Journal of the American Chemical Society|volume=69|issue=1|pages=17–20|doi=10.1021/ja01193a005|pmid=20291038|issn=0002-7863}}</ref>
: [[Image:Hentriacontane.svg|270px|thumb|right|The hydrocarbon [[Hentriacontane|C<sub>31</sub>H<sub>64</sub>]] is a typical component of paraffin wax.]]

Paraffin wax is an excellent [[electrical insulator]], with a [[resistivity]] of between 10<sup>13</sup> and 10<sup>17</sup> [[Resistivity|ohm-metre]].<ref name =kayelabyelec>{{cite web
| title =Electrical insulating materials
| work =Kaye and Laby Tables of Physical and Chemical Constants
| publisher =National Physical Laboratory
| year =1995
| url =http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_3.html
| access-date =25 October 2013
| archive-url =https://web.archive.org/web/20070927004133/http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_3.html
| archive-date =27 September 2007
| url-status =dead
}}</ref> This is better than nearly all other materials except some [[plastics]] (notably [[polytetrafluoroethylene|PTFE]]). It is an effective [[neutron moderator]] and was used in [[James Chadwick]]'s 1932 experiments to identify the neutron.<ref>{{cite web
| title =Attenuation of fast neutrons: neutron moderation and diffusion
| work =Kaye and Laby Tables of Physical and Chemical Constants
| publisher =National Physical Laboratory
| url =http://www.kayelaby.npl.co.uk/atomic_and_nuclear_physics/4_7/4_7_3.html
| access-date =25 October 2013
| archive-url =https://web.archive.org/web/20070929125508/http://www.kayelaby.npl.co.uk/atomic_and_nuclear_physics/4_7/4_7_3.html
| archive-date =29 September 2007
| url-status =dead
}}</ref><ref>{{cite book
| last =Rhodes
| first =Richard
| author-link =Richard Rhodes
| title =The Making of the Atomic Bomb
| publisher =Simon and Schuster
| year =1981
| location =New York
| page = [https://archive.org/details/makingofatomicbo00rhod/page/163 163]
| url =https://archive.org/details/makingofatomicbo00rhod
| url-access =registration
| isbn =978-0-671-44133-3}}</ref>

Paraffin wax is an excellent material for [[Phase change material|storing heat]], with a [[specific heat capacity]] of 2.14–2.9&nbsp;J⋅g<sup>−1</sup>⋅K<sup>−1</sup> ([[joules]] per [[gram]] per [[kelvin]]) and a [[Enthalpy of fusion|heat of fusion]] of 200–220&nbsp;J⋅g<sup>−1</sup>.<ref>{{cite encyclopedia| title =Specific Heat Capacity| encyclopedia =Diracdelta.co.uk Science and Engineering Encyclopedia| publisher =Dirac Delta Consultants Ltd, Warwick, England| url =http://www.diracdelta.co.uk/science/source/s/p/specific%20heat%20capacity/source.html| url-status =dead| access-date=25 October 2013| archive-url =https://web.archive.org/web/20070804192935/http://www.diracdelta.co.uk/science/source/s/p/specific%20heat%20capacity/source.html| archive-date =4 August 2007| df =dmy-all}}</ref> Paraffin wax phase-change cooling coupled with retractable radiators was used to cool the electronics of the [[Lunar Roving Vehicle]] during the crewed missions to the Moon in the early 1970s.<ref>{{cite journal |title=Space Station thermal storage/refrigeration system research and development |last1=Dean |first1=W. G. |last2=Karu |first2=Z. S. |date=February 1993 |journal=Final Report Lockheed Missiles and Space Co.}}</ref> Wax expands considerably when it melts and so is used in [[wax thermostatic element|wax element]] [[thermostat]]s for industrial, domestic and, particularly, automobile purposes.<ref>[http://www.freepatentsonline.com/4948043.html Wax-pellet thermostat] United States Patent 4948043</ref><ref name="rogerboden">{{cite web|url=http://hermes.material.uu.se/~klas/Paraffin_lab_eng.pdf|title=Paraffin Microactuator|last=Bodén|first=Roger|work=Materials Science Sensors and Actuators|publisher=University of Uppsala|archive-url=https://web.archive.org/web/20120208100013/http://hermes.material.uu.se/~klas/Paraffin_lab_eng.pdf|archive-date=8 February 2012|url-status=dead|access-date=25 October 2013}}</ref>

If pure paraffin wax melted to the approximate flash point in a half open glass vessel which is then suddenly cooled down, then its vapors may autoignite as result of reaching [[Boiling liquid expanding vapor explosion|boiling liquid pressure]].<ref>{{Cite web |last=Husting |first=Chad |date=2019-08-18 |title=Paraffin Wax – an Exothermic Reaction: Caution |url=https://www.chemedx.org/blog/paraffin-wax-exothermic-reaction-caution |access-date=2023-04-18 |website=Chemical Education Xchange |language=en}}</ref>

== History ==
Paraffin wax was first created in 1830 by German chemist [[Carl Reichenbach|Karl von Reichenbach]] when he attempted to develop a method to efficiently separate and refine waxy substances naturally occurring in petroleum. Paraffin represented a major advance in the candle-making industry because it burned cleanly and was cheaper to manufacture than other candle fuels such as [[beeswax]] and [[tallow]]. Paraffin wax initially suffered from a low melting point. This was remedied by adding [[stearic acid]]. The production of paraffin wax enjoyed a boom in the early 20th century due to the growth of the oil and meatpacking industries, which created paraffin and stearic acid as byproducts.<ref name="auto"/>

== Manufacturing ==
The feedstock for paraffin is [[Petroleum product#Specialty and By-products|slack wax]], which is a mixture of oil and wax, a byproduct from the refining of lubricating oil.

The first step in making paraffin wax is to remove the oil (de-oiling or de-waxing) from the slack wax. The oil is separated by crystallization. Most commonly, the slack wax is heated, mixed with one or more [[solvent]]s such as a [[ketone]] and then cooled. As it cools, wax crystallizes out of the solution, leaving only oil. This mixture is filtered into two streams: solid (wax plus some solvent) and liquid (oil and solvent). After the solvent is recovered by distillation, the resulting products are called "product wax" (or "press wax") and "foots oil". The lower the percentage of oil in the wax, the more refined it is considered to be (semi-refined versus fully refined).<ref>{{cite web |title=Paraffin Wax (Fully Refined) |url=http://www.barasatwax.com/fullyrefined.php |publisher=Barasat Wax Refiner |access-date=21 December 2012 |archive-url=https://web.archive.org/web/20130720100551/http://www.barasatwax.com/fullyrefined.php |archive-date=20 July 2013 |url-status=dead }}</ref> The product wax may be further processed to remove colors and odors. The wax may finally be blended together to give certain desired properties such as melt point and penetration. Paraffin wax is sold in either liquid or solid form.<ref>{{cite web |title=Wax Refining |url=http://igiwax.com/reference/wax-refining.html |publisher=The International Group, Inc. |access-date=21 December 2012 |archive-date=10 December 2012 |archive-url=https://web.archive.org/web/20121210142737/http://igiwax.com/reference/wax-refining.html |url-status=dead }}</ref><ref>{{cite web |title=Paraffin wax |url=http://bitumenengineering.com/materials/paraffin-wax |publisher=Bitumen Engineering |access-date=21 December 2012 |archive-url=https://web.archive.org/web/20120630024342/http://bitumenengineering.com/materials/paraffin-wax |archive-date=30 June 2012 |url-status=dead }}</ref><ref>{{cite web |title=Manufacturing Process |url=http://www.barasatwax.com/mp.php |publisher=Barasat Wax Refiner |access-date=21 December 2012 |archive-url=https://web.archive.org/web/20130720100707/http://barasatwax.com/mp.php |archive-date=20 July 2013 |url-status=dead }}</ref>

== Applications ==
In industrial applications, it is often useful to modify the crystal properties of the paraffin wax, typically by adding [[Branching (polymer chemistry)|branching]] to the existing carbon backbone chain. The modification is usually done with additives, such as [[Ethylene-vinyl acetate|EVA]] copolymers, [[microcrystalline wax]], or forms of [[polyethylene]]. The branched properties result in a modified paraffin with a higher viscosity, smaller crystalline structure, and modified functional properties. Pure paraffin wax is rarely used for carving original models for [[Casting (metalworking)|casting]] metal and other materials in the [[lost wax process]], as it is relatively brittle at room temperature and presents the risks of chipping and breakage when worked. Soft and pliable waxes, like [[beeswax]], may be preferred for such sculpture, but "[[investment casting]] waxes," often paraffin-based, are expressly formulated for the purpose.

In a histology or pathology laboratory, paraffin wax is used to impregnate tissue prior to sectioning thin samples. Water is removed from the tissue through ascending strengths of alcohol (75% to absolute), and then the alcohol is cleared in an organic solvent such as [[xylene]]. The tissue is then placed in paraffin wax for several hours, then set in a mold with wax to cool and solidify. Sections are then cut on a [[microtome]].

=== Other uses ===
* Agent for preparation of specimens for [[histology]]
* Anti-caking agent, moisture repellent, and dustbinding coatings for [[fertilizers]]
* [[Antiozonant]] agents: blends of paraffin and micro waxes are used in rubber compounds to prevent [[Ozone cracking|cracking]] of the rubber; the admixture of wax migrates to the surface of the product and forms a protective layer. The layer can also act as a [[release agent]], helping the product separate from its [[Molding (process)|mould]].<ref>{{harv|Freund|Mózes|1982|p=272}}</ref>
* [[Bicycle chain]] lubrication
* Bullet lubricant – with other ingredients, such as olive oil and [[beeswax]]
* [[Candle]]-making
* Coatings for [[waxed paper]] or [[waxed cotton]]
* Component of [[surfboard wax]], [[ski wax]], and [[Street skateboarding#Wax|skateboard wax]]
* [[Crayon]]s
* Food-grade paraffin wax:
** Shiny coating used in [[candy]]-making; although edible, it is nondigestible, passing through the body without being broken down
** Coating for many kinds of hard [[cheese]], like [[Edam cheese]]
** Sealant for jars, cans, and bottles
** Chewing gum additive
* [[Forensic investigation]]s: the nitrate test uses paraffin wax to detect nitrates and nitrites on the hand of a shooting suspect
* Fuel for [[Fire breathing (circus act)|fire breathing]]
* [[Investment casting]]
* [[Lava Lamps|Lava lamps]]
* Manufacture of [[boiled leather]] armor and books
* Mechanical [[Wax thermostatic element|thermostats]] and [[Paraffin microactuator|actuators]], as an expansion medium for activating such devices<ref name=rogerboden/><ref>{{cite journal|last=Ogden|first=Sam|author2=Klintberg, Lena |author3=Thornell, Greger |author4=Hjort, Klas |author5= Bodén, Roger |title=Review on miniaturized paraffin phase change actuators, valves, and pumps|journal=Microfluidics and Nanofluidics|volume=17|pages=53–71|date=30 November 2013|doi=10.1007/s10404-013-1289-3|s2cid=85525659|url=http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-208904}}</ref>
* Microwax:<ref>{{cite web|url=http://igiwax.com/igi-products/by-type/microcrystallinewax.html|title=Paraffin, microcrystalline, petrolatum, wax blends - Microcrystalline Wax|work=igiwax.com|access-date=29 April 2017|archive-date=19 October 2016|archive-url=https://web.archive.org/web/20161019214424/http://www.igiwax.com/igi-products/by-type/microcrystallinewax.html|url-status=dead}}</ref> [[food additive]], a [[glazing agent]] with [[E number]] E905
* [[Moisturiser]] in [[toiletries]] and [[cosmetics]] such as [[Vaseline]].
* [[Neutron radiation]] shielding
* [[Phase change material]] for [[thermal energy storage]]
** Used by [[MESSENGER]] (Mercury spacecraft), when the spacecraft was unable to radiate excessive heat.<ref>{{cite web |url=https://pds.nasa.gov/ds-view/pds/viewInstrumentProfile.jsp?INSTRUMENT_ID=MDIS-NAC&INSTRUMENT_HOST_ID=MESS |title= Instrument Information |work= [[NASA]] |date= 2007 |access-date= 24 January 2017}}</ref>{{failed verification|date=April 2024}}{{dead link|date=April 2024}}
* [[Phlegmatized|Phlegmatizing]] agent, commonly used to stabilise/desensitize [[high explosive]]s such as [[RDX]]
* [[Potting (electronics)|Potting]] material to encapsulate electronic components such as [[Pick up (music technology)|guitar pickups]], [[transformer]]s, and [[inductor]]s, to prevent moisture ingress and to reduce [[electromagnetically induced acoustic noise]] and [[Microphonics|microphonic effects]]
* Prevents [[Redox|oxidation]] on the surface of [[Steel|polished steel]] and [[iron]]<ref>
{{cite web |last=Dick |first=William B |title=Encyclopedia Of Practical Receipts And Processes |publisher=Dick and Fitzgerald |location=New York |year=1872 |url=http://chestofbooks.com/reference/Encyclopedia-Of-Practical-Receipts-And-Processes/Steel-Part-6.html |access-date=25 October 2013}}</ref>
* Solid [[ink]] color blocks of wax for [[Thermal printing|thermal printers]]. The wax is melted and then sprayed on the paper producing images with a shiny surface
* Solid propellant for [[hybrid rocket]] motors<ref>{{cite journal|last=Staff|date=Fall 2004|title=Rocket motor uses common household product for fuel|journal=OASIS Ocean Air Space Industry Site|volume=1|issue=3|pages=6|url=http://www.nasa.gov/centers/stennis/pdf/69281main_fall.pdf|access-date=28 November 2008}}</ref><ref>{{cite web |last1=Tabor |first1=Abigail |title=From Pedicures to the Peregrine Rocket, Paraffin Wax Proves Its Worth |url=https://www.nasa.gov/feature/ames/from-pedicures-to-the-peregrine-rocket-paraffin-wax-proves-its-worth |website=NASA.gov |access-date=26 March 2019 |date=18 April 2017 |archive-date=27 March 2019 |archive-url=https://web.archive.org/web/20190327005729/https://www.nasa.gov/feature/ames/from-pedicures-to-the-peregrine-rocket-paraffin-wax-proves-its-worth/ |url-status=dead }}</ref>
* Textile manufacturing processes, such as that used for [[Eisengarn]] thread
* Thickening agent in many [[paintballs]]
* Wax baths for [[Occupational therapy|occupational]] and [[Physical therapy|physical]] therapies and [[Manicure#Paraffin wax treatments|cosmetic treatments]]
* [[Wax carving]]
* [[Wood finishing]] 

== Occupational safety ==
People can be exposed to paraffin in the workplace by breathing it in, skin contact, and eye contact. The [[National Institute for Occupational Safety and Health]] (NIOSH) has set a [[recommended exposure limit]] (REL) for paraffin wax fume exposure of 2&nbsp;mg/m<sup>3</sup> over an 8-hour workday.<ref>{{Cite web|title = CDC – NIOSH Pocket Guide to Chemical Hazards – Paraffin wax fume|url = https://www.cdc.gov/niosh/npg/npgd0477.html|website = cdc.gov|access-date = 27 November 2015}}</ref>

== See also ==
* [[Oligomer]]
* [[Ozokerite]]

== References ==
{{reflist}}

== External links ==
{{commons category}}
* "[https://books.google.com/books?id=p4o9AQAAIAAJ Odd Uses of Paraffin]", [[Scientific American]], 13 July 1878, p.&nbsp;19

{{Authority control}}

[[Category:Waxes]]
[[Category:Alkanes]]
[[Category:Petroleum products]]
[[Category:Food additives]]
[[Category:E-number additives]]