Paraffin wax

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Paraffin wax
Paraffin.jpg
Identifiers
E number E905 (glazing agents, ...)
UNII
Properties
CnH2n+2
AppearanceWhite solid [1]
Odor Odorless
Boiling point > 370 °C (698 °F)
~1 mg/L [1]
Hazards
Flash point 200–240 °C (392–464 °F; 473–513 K) [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Paraffin candle Candle black.jpg
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 begins to melt above approximately 37 °C (99 °F), [2] and its boiling point is above 370 °C (698 °F). [2] Common applications for paraffin wax include lubrication, electrical insulation, and candles; [3] dyed paraffin wax can be made into crayons.

Un-dyed, unscented paraffin candles are odorless and bluish-white. Paraffin wax was first created by 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. [4]

In chemistry, paraffin is used synonymously with alkane , indicating hydrocarbons with the general formula CnH2n+2. The name is derived from Latin parum ("very little") + affinis, meaning "lacking affinity" or "lacking reactivity", referring to paraffin's unreactive nature. [5]

Properties

Paraffin wax is mostly found as a white, odorless, flavourless, waxy solid, with a typical melting point between about 46 and 68 °C (115 and 154 °F), [6] and a density of around 900 kg/m3. [7] It is insoluble in water, but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents but burns readily. [8] Its heat of combustion is 42 MJ/kg. [9]

The hydrocarbon C31H64 is a typical component of paraffin wax. Hentriacontane.svg
The hydrocarbon C31H64 is a typical component of paraffin wax.

Paraffin wax is an excellent electrical insulator, with a resistivity of between 1013 and 1017 ohm-metre. [10] 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. [11] [12]

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. [13] 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. [14] Wax expands considerably when it melts and so is used in wax element thermostats for industrial, domestic and, particularly, automobile purposes. [15] [16]

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. [17]

History

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. [4]

Manufacturing

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). [18] 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. [19] [20] [21]

Applications

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.

Other uses

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 mg/m3 over an 8-hour workday. [29]

See also

Related Research Articles

<span class="mw-page-title-main">Beeswax</span> Natural wax produced by honey bees of the genus Apis

Beeswax is a natural wax produced by honey bees of the genus Apis. The wax is formed into scales by eight wax-producing glands in the abdominal segments of worker bees, which discard it in or at the hive. The hive workers collect and use it to form cells for honey storage and larval and pupal protection within the beehive. Chemically, beeswax consists mainly of esters of fatty acids and various long-chain alcohols.

<span class="mw-page-title-main">Candle</span> Wick embedded in solid flammable substance

A candle is an ignitable wick embedded in wax, or another flammable solid substance such as tallow, that provides light, and in some cases, a fragrance. A candle can also provide heat or a method of keeping time. Candles have been used for over two millennia around the world, and were a significant form of indoor lighting until the invention of other types of light sources. Although electric light has largely made candle use nonessential for illumination, candles are still commonly used for functional, symbolic and aesthetic purposes and in specific cultural and religious settings.

<span class="mw-page-title-main">Wax</span> Class of organic compounds which are malleable at room temperature

Waxes are a diverse class of organic compounds that are lipophilic, malleable solids near ambient temperatures. They include higher alkanes and lipids, typically with melting points above about 40 °C (104 °F), melting to give low viscosity liquids. Waxes are insoluble in water but soluble in nonpolar organic solvents such as hexane, benzene and chloroform. Natural waxes of different types are produced by plants and animals and occur in petroleum.

<span class="mw-page-title-main">Petroleum jelly</span> Chemical substance used as a lubricating agent and topical ointment

Petroleum jelly, petrolatum, white petrolatum, soft paraffin, or multi-hydrocarbon, CAS number 8009-03-8, is a semi-solid mixture of hydrocarbons, originally promoted as a topical ointment for its healing properties. Vaseline has been an American brand of petroleum jelly since 1870.

<span class="mw-page-title-main">Rosin</span> Solid form of resin

Rosin, also known as colophony or Greek pitch, is a solid form of resin obtained from pine trees and other plants, mostly conifers, primarily through heating fresh liquid resin to vaporize the volatile liquid terpene components. Used widely in various industries and arts, rosin appears as a semi-transparent, brittle substance that ranges in color from yellow to black and melts at stove-top temperatures. Rosin consists mainly of resin acids, especially abietic acid, and is soluble in alcohol, ether, benzene and chloroform.

<span class="mw-page-title-main">Wax play</span> Method of sadomasochistic play

Wax play is a form of temperature play practiced in a BDSM context, in which wax from a candle is dripped onto a person's naked skin, in order to introduce a slight burning sensation to the skin.

<span class="mw-page-title-main">Buddy Burner</span>

A Buddy Burner is a simple stove made from a can and part of a corrugated paper box. It is usually fueled by paraffin wax but other fuels, such as boiled butter, animal fat or diesel fuel, can be used. It is usually used for cooking but can also provide heat.

<span class="mw-page-title-main">Ozokerite</span> Mineral wax

Ozokerite or ozocerite, archaically referred to as earthwax or earth wax, is a naturally occurring odoriferous mineral wax or paraffin found in many localities. Lacking a definite composition and crystalline structure, it is not considered a mineral but only a mineraloid. The name was coined from Greek elements Όζω ozο, to stink, and κηρός keros, wax.

<span class="mw-page-title-main">Phase-change material</span> Substance with high latent heat of melting or solidifying

A phase-change material (PCM) is a substance which releases/absorbs sufficient energy at phase transition to provide useful heat or cooling. Generally the transition will be from one of the first two fundamental states of matter - solid and liquid - to the other. The phase transition may also be between non-classical states of matter, such as the conformity of crystals, where the material goes from conforming to one crystalline structure to conforming to another, which may be a higher or lower energy state.

Calumet, Inc. is a publicly traded U.S.-based company that was incorporated in 1919. It specializes in the manufacture of lubricating oils, solvents, waxes, packaged and synthetic specialty products, fuels and fuel-related products. The company operates 12 production, blending, and packaging facilities across North America. This includes locations in Princeton, Cotton Valley, and Shreveport, Louisiana; Burnham, Illinois; Dickinson, Texas; Muncie, Indiana; Karns City, Pennsylvania; and Great Falls, Montana. Calumet's specialized hydrocarbon products are distributed around the world to approximately 2,700 global customers.

A glazing agent is a natural or synthetic substance that provides a waxy, homogeneous coating to prevent water loss from a surface and provide other protection.

Microcrystalline waxes are a type of wax produced by de-oiling petrolatum, as part of the petroleum refining process. In contrast to the more familiar paraffin wax which contains mostly unbranched alkanes, microcrystalline wax contains a higher percentage of isoparaffinic (branched) hydrocarbons and naphthenic hydrocarbons. It is characterized by the fineness of its crystals in contrast to the larger crystal of paraffin wax. It consists of high molecular weight saturated aliphatic hydrocarbons. It is generally darker, more viscous, denser, tackier and more elastic than paraffin waxes, and has a higher molecular weight and melting point. The elastic and adhesive characteristics of microcrystalline waxes are related to the non-straight chain components which they contain. Typical microcrystalline wax crystal structure is small and thin, making them more flexible than paraffin wax. It is commonly used in cosmetic formulations.

<span class="mw-page-title-main">History of candle making</span>

Candle making was developed independently in a number of countries around the world.

Higher alkanes refer to alkanes with a high number of carbon atoms. There does not exist a formal definition for when an alkane is classified as a 'higher alkane', but one definition distinguishes the higher alkanes as the n-alkanes that are solid under room temperature.

<span class="mw-page-title-main">Fractional crystallization (chemistry)</span> Method for refining substances based on differences in their solubility

In chemistry, fractional crystallization is a stage-wise separation technique that relies on the liquid-solid phase change. fractional crystallisation. This is an old established method which is nevertheless capable of excellent results and a description is available in "The practical Methods of organic Chemistry" by Ludwig Gattermann in 1898 and a translation was available in English by WILLIAM B. SHOBER who was a Lehigh University, USA.

<span class="mw-page-title-main">Soy candle</span> Common candle type

Soy candles are candles made from soy wax, which is a processed form of soybean oil. They are usually container candles because soy wax typically has a lower melting point than traditional waxes, but can also be made into pillar candles if certain additives are mixed into the soy wax.

<span class="mw-page-title-main">Wax thermostatic element</span>

The wax thermostatic element was invented in 1934 by Sergius Vernet (1899–1968). Its principal application is in automotive thermostats used in the engine cooling system. The first applications in the plumbing and heating industries were in Sweden (1970) and in Switzerland (1971).

<span class="mw-page-title-main">Renaissance Wax</span>

Renaissance Wax is a brand of microcrystalline wax polish used in antique restoration and museum conservation around the world. Commonly used to polish and conserve metal objects, it is also used on gemstones and such organic materials as wood, ivory, and tortoiseshell. The product is sometimes used by reenactors to protect armor and weapons. Waxes are more protective and longer-lasting than oil, especially for swords and helmets that are frequently touched by human hands. It has recently been introduced in the world of guitar building, as a finish that protects and gives colour to the wood.

Crude oil is extracted from the bedrock before being processed in several stages, removing natural contaminants and undesirable hydrocarbons. This separation process produces mineral oil, which can in turn be denoted as paraffinic, naphthenic or aromatic. The differences between these different types of oils are not clear-cut, but mainly depend on the predominant hydrocarbon types in the oil. Paraffinic oil, for example, contains primarily higher alkanes, whereas naphthenic oils have a high share of cyclic alkanes in the mixture.

Wax emulsions are stable mixtures of one or more waxes in water. Waxes and water are normally immiscible but can be brought together stably by the use of surfactants and a clever preparation process. Strictly speaking a wax emulsion should be called a wax dispersion since the wax is solid at room temperature. However, because the preparation takes place above the melting point of the wax, the actual process is called emulsification, hence the name wax emulsion. In praxis, wax dispersion is used for solvent based systems.

References

  1. 1 2 3 Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  2. 1 2 Freund, Mihály; Mózes, Gyula (1982). Paraffin products: properties, technologies, applications. Translated by Jakab, E. Amsterdam, the Netherlands: Elsevier. p. 121. ISBN   978-0-444-99712-8.
  3. ↑ Raw materials and candles production processes Archived 21 March 2020 at the Wayback Machine , AECM
  4. 1 2 "History of Candles". National Candle Association. Retrieved 25 February 2016.
  5. ↑ "Paraffin, n". Oxford English Dictionary. Oxford, England: Oxford University Press. March 2009.
  6. ↑ Nasser, William E (1999). "Waxes, Natural and Synthetic". In McKetta, John J (ed.). Encyclopedia of Chemical Processing and Design. Vol. 67. New York: Marcel Dekker. p. 17. ISBN   978-0-8247-2618-8. This can vary widely, even outside the quoted range, according to such factors as oil content and crystalline structure.
  7. ↑ Kaye, George William Clarkson; Laby, Thomas Howell. "Mechanical properties of materials". Kaye and Laby Tables of Physical and Chemical Constants. National Physical Laboratory. Archived from the original on 11 March 2008. Retrieved 25 October 2013.
  8. ↑ Seager, Spencer L.; Slabaugh, Michael (19 January 2010). "Alkane reactions". Chemistry for Today: General, Organic, and Biochemistry. Belmont, California: Cengage. p. 364. ISBN   978-0-538-73332-8.
  9. ↑ Wiener, Harry (January 1947). "Structural Determination of Paraffin Boiling Points". Journal of the American Chemical Society. 69 (1): 17–20. doi:10.1021/ja01193a005. ISSN   0002-7863. PMID   20291038.
  10. ↑ "Electrical insulating materials". Kaye and Laby Tables of Physical and Chemical Constants. National Physical Laboratory. 1995. Archived from the original on 27 September 2007. Retrieved 25 October 2013.
  11. ↑ "Attenuation of fast neutrons: neutron moderation and diffusion". Kaye and Laby Tables of Physical and Chemical Constants. National Physical Laboratory. Archived from the original on 29 September 2007. Retrieved 25 October 2013.
  12. ↑ Rhodes, Richard (1981). The Making of the Atomic Bomb . New York: Simon and Schuster. p.  163. ISBN   978-0-671-44133-3.
  13. ↑ "Specific Heat Capacity". Diracdelta.co.uk Science and Engineering Encyclopedia. Dirac Delta Consultants Ltd, Warwick, England. Archived from the original on 4 August 2007. Retrieved 25 October 2013.
  14. ↑ Dean, W. G.; Karu, Z. S. (February 1993). "Space Station thermal storage/refrigeration system research and development". Final Report Lockheed Missiles and Space Co.
  15. ↑ Wax-pellet thermostat United States Patent 4948043
  16. 1 2 Bodén, Roger. "Paraffin Microactuator" (PDF). Materials Science Sensors and Actuators. University of Uppsala. Archived from the original (PDF) on 8 February 2012. Retrieved 25 October 2013.
  17. ↑ Husting, Chad (18 August 2019). "Paraffin Wax – an Exothermic Reaction: Caution". Chemical Education Xchange. Retrieved 18 April 2023.
  18. ↑ "Paraffin Wax (Fully Refined)". Barasat Wax Refiner. Archived from the original on 20 July 2013. Retrieved 21 December 2012.
  19. ↑ "Wax Refining". The International Group, Inc. Archived from the original on 10 December 2012. Retrieved 21 December 2012.
  20. ↑ "Paraffin wax". Bitumen Engineering. Archived from the original on 30 June 2012. Retrieved 21 December 2012.
  21. ↑ "Manufacturing Process". Barasat Wax Refiner. Archived from the original on 20 July 2013. Retrieved 21 December 2012.
  22. ↑ ( Freund & Mózes 1982 , p. 272)
  23. ↑ Ogden, Sam; Klintberg, Lena; Thornell, Greger; Hjort, Klas; Bodén, Roger (30 November 2013). "Review on miniaturized paraffin phase change actuators, valves, and pumps". Microfluidics and Nanofluidics. 17: 53–71. doi:10.1007/s10404-013-1289-3. S2CID   85525659.
  24. ↑ "Paraffin, microcrystalline, petrolatum, wax blends - Microcrystalline Wax". igiwax.com. Archived from the original on 19 October 2016. Retrieved 29 April 2017.
  25. ↑ "Instrument Information". NASA . 2007. Retrieved 24 January 2017.
  26. ↑ Dick, William B (1872). "Encyclopedia Of Practical Receipts And Processes". New York: Dick and Fitzgerald. Retrieved 25 October 2013.
  27. ↑ Staff (Fall 2004). "Rocket motor uses common household product for fuel" (PDF). OASIS Ocean Air Space Industry Site. 1 (3): 6. Retrieved 28 November 2008.
  28. ↑ Tabor, Abigail (18 April 2017). "From Pedicures to the Peregrine Rocket, Paraffin Wax Proves Its Worth". NASA.gov. Archived from the original on 27 March 2019. Retrieved 26 March 2019.
  29. ↑ "CDC – NIOSH Pocket Guide to Chemical Hazards – Paraffin wax fume". cdc.gov. Retrieved 27 November 2015.
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