paraffin wax#Wax

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}},{{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. and a density of around 900 kg/m³.{{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

| 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

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}} It is insoluble in water, but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents but burns readily.{{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}} Its heat of combustion is 42 MJ/kg.{{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|url-access=subscription}}

: Image:Hentriacontane.svg is a typical component of paraffin wax.]]

Paraffin wax is an excellent electrical insulator, with a resistivity of between 10¹³ and 10¹⁷ ohm-metre.{{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

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}} This is better than nearly all other materials except some plastics (notably PTFE). It is an effective neutron moderator and was used in James Chadwick's 1932 experiments to identify the neutron.{{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

}}{{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}}

Paraffin wax is an excellent material for storing heat, with a specific heat capacity of 2.14–2.9 J⋅g⁻¹⋅K⁻¹ (joules per gram per kelvin) and a heat of fusion of 200–220 J⋅g⁻¹.{{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}} 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.{{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.}} Wax expands considerably when it melts and so is used in wax element thermostats for industrial, domestic and, particularly, automobile purposes.[http://www.freepatentsonline.com/4948043.html Wax-pellet thermostat] United States Patent 4948043{{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}}

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 pressure.{{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}}

Paraffin wax was first created in 1830 by German chemist 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.

The feedstock for paraffin is 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 solvents 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).{{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 }} 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.{{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 }}{{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 }}{{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 }}

In industrial applications, it is often useful to modify the crystal properties of the paraffin wax, typically by adding branching to the existing carbon backbone chain. The modification is usually done with additives, such as 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 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.

• 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 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 mould.{{harv|Freund|Mózes|1982|p=272}}
• 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 skateboard wax
• Crayons
• 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 investigations: the nitrate test uses paraffin wax to detect nitrates and nitrites on the hand of a shooting suspect
• Fuel for fire breathing
• Investment casting
• Lava lamps
• Manufacture of boiled leather armor and books
• Mechanical thermostats and actuators, as an expansion medium for activating such devices{{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}}
• Microwax:{{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}} 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.{{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}}{{failed verification|date=April 2024}}{{dead link|date=April 2024}}
• Phlegmatizing agent, commonly used to stabilise/desensitize high explosives such as RDX
• Potting material to encapsulate electronic components such as guitar pickups, transformers, and inductors, to prevent moisture ingress and to reduce electromagnetically induced acoustic noise and microphonic effects
• Prevents oxidation on the surface of polished steel and iron

{{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}}

• Solid ink color blocks of wax for thermal printers. The wax is melted and then sprayed on the paper producing images with a shiny surface
• Solid propellant for hybrid rocket motors{{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}}{{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 }}
• Textile manufacturing processes, such as that used for Eisengarn thread
• Thickening agent in many paintballs
• Wax baths for occupational and physical therapies and cosmetic treatments
• Wax carving
• Wood finishing

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 mg/m³ over an 8-hour workday.{{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}}

• Oligomer
• Ozokerite

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{{commons category}}

• "[https://books.google.com/books?id=p4o9AQAAIAAJ Odd Uses of Paraffin]", Scientific American, 13 July 1878, p. 19

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Category:Waxes

Category:Alkanes

Category:Petroleum products

Category:Food additives

Category:E-number additives