Paraffin wax

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Paraffin wax
Paraffin.jpg
Identifiers
ECHA InfoCard 100.029.375
E number E905 (glazing agents, ...)
UNII
Properties
CnH2n+2
AppearanceWhite solid [1]
Odor Odorless [1]
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).
Infobox references
Paraffin candle Candle black.jpg
Paraffin candle

Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal or shale oil that consists of a mixture of hydrocarbon molecules containing between twenty and forty 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). [3] Common applications for paraffin wax include lubrication, electrical insulation, and candles; [4] dyed paraffin wax can be made into crayons. It is distinct from kerosene and other petroleum products that are sometimes called paraffin. [5]

Contents

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. [6]

In chemistry, paraffin is used synonymously with alkane , indicating hydrocarbons with the general formula CnH2n+2. The name is derived from Latin parum ("barely") + affinis, meaning "lacking affinity" or "lacking reactivity", referring to paraffin's unreactive nature. [7]

Properties

Paraffin wax is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 46 and 68 °C (115 and 154 °F), [8] and a density of around 900 kg/m3. [9] It is insoluble in water, but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents but burns readily. [10] Its heat of combustion is 42 MJ/kg.

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. [11] This is better than nearly all other materials except some plastics (notably Teflon). It is an effective neutron moderator and was used in James Chadwick's 1932 experiments to identify the neutron. [12] [13]

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 kelvin) and a heat of fusion of 200–220 J g−1. [14] Paraffin wax phase-change cooling coupled with retractable radiators was used to cool the electronics of the Lunar Roving Vehicle during the manned missions to the Moon in the early 1970s. [15] Wax expands considerably when it melts and this allows its use in wax element thermostats for industrial, domestic and, particularly, automobile purposes. [16] [17]

History

Paraffin wax was first created in 1830 by the German chemist Karl von Reichenbach when he tried to develop the means to efficiently separate and refine the waxy substances naturally occurring in petroleum. Paraffin represented a major advance in the candlemaking industry because it burned more cleanly and reliably and was cheaper to manufacture than any other candle fuel. Paraffin wax initially suffered from a low melting point; however, this shortcoming was later remedied by the addition of harder stearic acid. The production of paraffin wax enjoyed a boom in the early 20th century as a result of the growth of the meatpacking and oil industries which created paraffin and stearic acid as byproducts. [6]

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 (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 of tissue. Water is removed from the tissue through ascending strengths of alcohol (75% to absolute) and the tissue is cleared in an organic solvent such as xylene. The tissue is then placed in paraffin wax for a number of hours and 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

A lubricant is a substance, usually organic, introduced to reduce friction between surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces move. It may also have the function of transmitting forces, transporting foreign particles, or heating or cooling the surfaces. The property of reducing friction is known as lubricity.

Beeswax chemical compound

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.

Candle solid block of wax with embedded wick

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.

Wax class of chemical compounds that are plastic (malleable) near ambient temperatures.

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 organic, nonpolar solvents. Natural waxes of different types are produced by plants and animals and occur in petroleum.

Petroleum jelly Chemical substance used as lubricating agent

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.

Wax play form of temperature play practiced in a BDSM context

Wax play is a form of temperature play practiced in a BDSM context. The idea of wax play is to introduce a slight burning sensation to the skin.

Ski wax material applied to the bottom of snow runners, including skis, snowboards, and toboggans, to improve their coefficient of friction performance under varying snow conditions

Ski wax is a material applied to the bottom of snow runners, including skis, snowboards, and toboggans, to improve their coefficient of friction performance under varying snow conditions. The two main types of wax used on skis are glide waxes and grip waxes. They address kinetic friction—to be minimized with a glide wax—and static friction—to be achieved with a grip wax. Both types of wax are designed to be matched with the varying properties of snow, including crystal type and size, and moisture content of the snow surface, which vary with temperature and the temperature history of the snow. Glide wax is selected to minimize sliding friction for both alpine and cross-country skiing. Grip wax provides on-snow traction for cross-country skiers, as they stride forward using classic technique.

Buddy Burner An improvised heating/cooking device made out of metal can and corrugated paper

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.

Petroleum product useful material derived from crude oil (petroleum)

Petroleum products are materials derived from crude oil (petroleum) as it is processed in oil refineries. Unlike petrochemicals, which are a collection of well-defined usually pure chemical compounds, petroleum products are complex mixtures. The majority of petroleum is converted to petroleum products, which includes several classes of fuels.

Ozokerite naturally occurring odoriferous mineral wax or paraffin

Ozokerite or ozocerite, archaically referred to as earthwax or earth wax, is a naturally occurring odoriferous mineral wax or paraffin found in many localities.

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.

Hot-melt adhesive solvent-free and at room temperature more or less solid products which are applied to the adhesive surface when hot

Hot melt adhesive (HMA), also known as hot glue, is a form of thermoplastic adhesive that is commonly sold as solid cylindrical sticks of various diameters designed to be applied using a hot glue gun. The gun uses a continuous-duty heating element to melt the plastic glue, which the user pushes through the gun either with a mechanical trigger mechanism on the gun, or with direct finger pressure. The glue squeezed out of the heated nozzle is initially hot enough to burn and even blister skin. The glue is tacky when hot, and solidifies in a few seconds to one minute. Hot melt adhesives can also be applied by dipping or spraying, and are popular with hobbyists and crafters both for affixing and as an inexpensive alternative to resin casting.

History of candle making aspect of history

Candle making was developed independently in many places throughout history.

Higher alkanes are alkanes having nine or more carbon atoms. Nonane is the lightest alkane to have a flash point above 25 °C, and is not classified as dangerously flammable.

Soy candle candles made from soy wax

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.

A melting tank is a tank used by manufacturing companies to manufacture a variety of products.

Hash oil Resinous matrix of cannabinoids derived from cannabis

Hash oil, also known as honey oil or cannabis oil, is an oleoresin obtained by the extraction of cannabis or hashish. It is a cannabis concentrate containing many of its resins and terpenes – in particular, tetrahydrocannabinol (THC), cannabidiol (CBD), and other cannabinoids. There are various extraction methods, most involving a solvent, such as butane or ethanol. Hash oil is usually consumed by smoking, vaporizing or eating. Hash oil may be sold in cartridges used with pen vaporizers. Preparations of hash oil may be solid or colloidal depending on both production method and temperature and are usually identified by their appearance or characteristics. Color most commonly ranges from transparent golden or light brown, to tan or black. Cannabis retailers in California have reported about 40% of their sales are from cannabis oils. Hash oil is an extracted cannabis product that may use any part of the plant, with minimal or no residual solvent. It is generally thought to be indistinct from traditional hashish, according to the 1961 UN Single Convention on Narcotic Drugs, as it is "the separated resin, whether crude or purified, obtained from the cannabis plant".

Conservation and restoration of ceramic objects

Conservation and restoration of ceramic objects is a process dedicated to the preservation and protection of objects of historical and personal value made from ceramic. Typically this activity of conservation-restoration is undertaken by a conservator-restorer, especially when dealing with an object of cultural heritage. Ceramics are created from a production of coatings of inorganic, nonmetallic materials using heating and cooling to create a glaze. Typically the coatings are permanent and sustainable for utilitarian and decorative purposes. The cleaning, handling, storage, and in general treatment of ceramics is consistent with that of glass because they are made of similar oxygen-rich components, such as silicates. In conservation ceramics are broken down into three groups: unfired clay, earthenware or terracotta, and stoneware and porcelain.

A wax emulsion is a stable mixture 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 4 Record in the GESTIS Substance Database of the Institute for Occupational Safety and Health
  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.CS1 maint: ref=harv (link)
  3. "Paraffin Wax". Chemical book. Retrieved 25 October 2013.
  4. Raw materials and candles production processes, AECM
  5. Charles B. Willingham; William J. Taylor; Joan M. Pignocco; Frederick D. Rossini. "Research Paper RP1670 | Vapor Pressures and Boiling Points of Some Paraffin, Alkylcycopentane, Alkylcyclohexane and Alkylbenzene Hydrocarbons" (PDF). National Institute of Standards and Technology . US Department of Commerce National Bureau of Standards.
  6. 1 2 "History of Candles". National Candle Association. Retrieved 25 February 2016.
  7. "Paraffin, n". Oxford English Dictionary. Oxford, England: Oxford University Press. March 2009.
  8. Nasser, William E (1999). "Waxes, Natural and Synthetic". In McKetta, John J (ed.). Encyclopedia of Chemical Processing and Design. 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.
  9. 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.
  10. 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.
  11. "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.
  12. "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.
  13. Rhodes, Richard (1981). The Making of the Atomic Bomb . New York: Simon and Schuster. p.  163. ISBN   978-0-671-44133-3.
  14. "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.
  15. Dean, W. G.; Karu, Z. S. (February 1993). "Space Station thermal storage/refrigeration system research and development". Final Report Lockheed Missiles and Space Co. Bibcode:1993lock.rept.....D.
  16. Wax-pellet thermostat United States Patent 4948043
  17. 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.
  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. 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. 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.
  23. Tabor, Abigail (18 April 2017). "From Pedicures to the Peregrine Rocket, Paraffin Wax Proves Its Worth". NASA.gov. Retrieved 26 March 2019.
  24. "Paraffin, microcrystalline, petrolatum, wax blends - Microcrystalline Wax". igiwax.com. Retrieved 29 April 2017.
  25. ( Freund & Mózes 1982 , p. 272)
  26. Dick, William B (1872). "Encyclopedia Of Practical Receipts And Processes". New York: Dick and Fitzgerald. Retrieved 25 October 2013.
  27. "Instrument Information". NASA . 2007. Retrieved 24 January 2017.
  28. 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.
  29. "CDC - NIOSH Pocket Guide to Chemical Hazards - Paraffin wax fume". cdc.gov. Retrieved 27 November 2015.