Difference between revisions of "Paraffin" - New World Encyclopedia
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| − | '''Paraffin''' is a common name for a group of [[alkane]] [[hydrocarbon]]s with the general formula C<sub>''n''</sub>H<sub>2''n''+2</sub>, where ''n'' is the number of carbon | + | '''Paraffin''' is a common name for a group of [[alkane]] [[hydrocarbon]]s with the general formula C<sub>''n''</sub>H<sub>2''n''+2</sub>, where ''n'' is the number of [[carbon]] [[atom]]s. The simplest paraffin [[molecule]] is that of [[methane]], CH<SUB>4</SUB>, a [[gas]] at room [[temperature]]. Heavier members of the series, such as that of [[octane]] C<SUB>8</SUB>H<SUB>18</SUB>, appear as [[liquid]]s at room temperature. The [[solid]] forms of paraffin, called ''paraffin wax'', are from the heaviest molecules from C<sub>20</sub> to C<sub>40</sub>. Paraffin wax was identified by [[Carl Reichenbach]] in 1830. |
| − | ''Paraffin'', or ''paraffin hydrocarbon'', is also the technical name for an alkane in general, but in most cases it refers specifically to a linear, or ''normal'' | + | ''Paraffin'', or ''paraffin hydrocarbon'', is also the technical name for an alkane in general, but in most cases it refers specifically to a linear, or ''normal'' alkane—whereas branched, or ''iso''alkanes are also called ''iso''paraffins. It is distinct from the fuel known in [[Great Britain|Britain]] and [[South Africa]] as ''paraffin oil'' or just ''paraffin'', which is called [[kerosene]] in much of the [[United States|U.S.]], [[Australia]] and [[New Zealand]]. |
== Etymology == | == Etymology == | ||
| − | The name ''paraffin'' is derived from the Latin words ''parum'', meaning "barely," and ''affinis'', meaning "affinity." Thus the combination of words means "lacking [[electron affinity|affinity]]" or "lacking [[reactivity]]." | + | The name ''paraffin'' is derived from the [[Latin]] words ''parum'', meaning "barely," and ''affinis'', meaning "affinity." Thus the combination of words means "lacking [[electron affinity|affinity]]" or "lacking [[reactivity]]." |
==Wax== | ==Wax== | ||
| − | Paraffin wax is mostly found as a white, odorless, tasteless, [[wax]]y solid, with a typical melting point between about 47 °C and 64 °C. 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. | + | Paraffin wax is mostly found as a white, odorless, tasteless, [[wax]]y solid, with a typical melting point between about 47 °C and 64 °C. 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. |
| − | Pure paraffin wax is an extremely good electrical [[Electrical insulation|insulator]], with an electrical [[resistivity]] of between <math>10^{13}</math> and <math>10^{17}</math> ohm meter.<ref name =kayelaby>[http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_3.html Electrical insulating materials] | + | Pure paraffin wax is an extremely good electrical [[Electrical insulation|insulator]], with an electrical [[resistivity]] of between <math>10^{13}</math> and <math>10^{17}</math> ohm meter.<ref name =kayelaby>[http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_3.html Electrical insulating materials] National Physical Laboratory, UK. Retrieved December 2, 2007.</ref> 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.<ref>[http://www.kayelaby.npl.co.uk/atomic_and_nuclear_physics/4_7/4_7_3.html Attenuation of fast neutrons: neutron moderation and diffusion]. National Physical Laboratory, UK. Retrieved December 2, 2007.</ref><ref>Rhodes, Richard. 1986. ''The Making of the Atomic Bomb''. New York, NY: Simon and Schuster. ISBN 0-671-44133-7</REF> |
| − | Paraffin wax (C<sub>25</sub>H<sub>52</sub>) is an excellent material to store heat, having a [[specific heat capacity]] of 2.14–2.9 J g<sup>–1</sup> K<sup>–1</sup> and a [[Enthalpy of fusion|heat of fusion]] of 200–220 J/g.<ref>[http://www.diracdelta.co.uk/science/source/s/p/specific%20heat%20capacity/source.html Specific Heat Capacity] | + | Paraffin wax (C<sub>25</sub>H<sub>52</sub>) is an excellent material to store heat, having a [[specific heat capacity]] of 2.14–2.9 J g<sup>–1</sup> K<sup>–1</sup> and a [[Enthalpy of fusion|heat of fusion]] of 200–220 J/g.<ref>[http://www.diracdelta.co.uk/science/source/s/p/specific%20heat%20capacity/source.html Specific Heat Capacity] Dirac Delta Consultants Ltd, Warwick, England. Retrieved December 2, 2007.</ref> The substance expands considerably when it melts and this property is exploited in [[thermostat]]s for industrial, domestic and, particularly, automobile use.<ref>[http://www.freepatentsonline.com/4948043.html Wax-pellet thermostat] United States Patent 4948043. Retrieved December 2, 2007.</ref> |
For casting of metal and other materials, "investment casting waxes" are used, in which the paraffin wax is combined with several other materials to obtain the desired properties. Paraffin wax is not much used to make original models for [[casting]], as it is relatively brittle at room temperature and usually cannot be cold-carved without excessive chipping and breaking. Soft, pliable waxes such as [[beeswax]] are preferred for these purposes. | For casting of metal and other materials, "investment casting waxes" are used, in which the paraffin wax is combined with several other materials to obtain the desired properties. Paraffin wax is not much used to make original models for [[casting]], as it is relatively brittle at room temperature and usually cannot be cold-carved without excessive chipping and breaking. Soft, pliable waxes such as [[beeswax]] are preferred for these purposes. | ||
| − | In industrial uses, it is often useful to modify the crystal properties of the paraffin wax, typically by adding branching to the existing carbon backbone chain. | + | In industrial uses, 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 [[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. |
==Liquid paraffin== | ==Liquid paraffin== | ||
| − | [[Mineral oil|Liquid paraffin]], a mixture of heavier alkanes, has a number of names, including nujol, adepsine oil, alboline, glymol, | + | [[Mineral oil|Liquid paraffin]], a mixture of heavier alkanes, has a number of names, including nujol, adepsine oil, alboline, glymol, medicinal paraffin, saxol, or USP mineral oil. It is often used in [[infrared spectroscopy]], as it has a relatively uncomplicated [[IR spectrum]]. When the sample to be tested is made into a [[mull]] (a very thick solution), liquid paraffin is added so it can be spread on the disks to be tested. [[Liquid paraffin (medicinal)]] is used to aid bowel movement in persons suffering chronic constipation; it passes through the [[alimentary canal]] without itself being taken into the body, but it limits the amount of water removed from the [[Human feces|stool]]. In the food industry, where it may be called "wax," it can be used as a lubricant in mechanical mixing, applied to baking tins to ensure that loaves are easily released when cooked and as a coating for fruit or other items requiring a "shiny" appearance for sale.<ref>[http://www.inchem.org/documents/jecfa/jecmono/v10je08.htm Mineral Oil (Food Grade)] Food and Agriculture Organization of the United Nations; World Health Organization. Retrieved December 2, 2007.</ref> |
==Uses== | ==Uses== | ||
| Line 38: | Line 38: | ||
*Coatings for waxed paper or cloth | *Coatings for waxed paper or cloth | ||
*Food-grade paraffin wax: | *Food-grade paraffin wax: | ||
| − | **Shiny coating used in [[candy]]-making; although edible, it is nondigestible, passing right through the body without being broken down | + | **Shiny coating used in [[candy]]-making; although edible, it is nondigestible, passing right through the body without being broken down. |
**[[Magic Shell]] | **[[Magic Shell]] | ||
**Coating for many kinds of hard [[cheese]], like [[Edam cheese]]. | **Coating for many kinds of hard [[cheese]], like [[Edam cheese]]. | ||
| Line 44: | Line 44: | ||
**Chewing gum additive | **Chewing gum additive | ||
*[[Investment casting]] | *[[Investment casting]] | ||
| − | *Anti-caking agent, moisture repellent, and dustbinding coatings for [[fertilizers]] | + | *Anti-caking agent, moisture repellent, and dustbinding coatings for [[fertilizers]]. |
| − | *Agent for preparation of specimens for [[histology]] | + | *Agent for preparation of specimens for [[histology]]. |
| − | *Solid propellant for [[hybrid rocket]] motors | + | *Solid propellant for [[hybrid rocket]] motors. |
| − | *[[Emollient]] (moisturiser), in [[dermatology]] | + | *[[Emollient]] (moisturiser), in [[dermatology]]. |
| − | *Component of [[surfwax]], used for grip on surfboards in [[surfing]] | + | *Component of [[surfwax]], used for grip on surfboards in [[surfing]]. |
*Component of [[ski wax|glide wax]], used on [[ski]]s and [[snowboard]]s. | *Component of [[ski wax|glide wax]], used on [[ski]]s and [[snowboard]]s. | ||
| − | *Friction-reducer, for use on handrails and cement ledges, commonly used in [[skateboarding]] | + | *Friction-reducer, for use on handrails and cement ledges, commonly used in [[skateboarding]]. |
| − | *Microwax | + | *Microwax [[food additive]], a [[glazing agent]] with [[E number]] E905 |
| − | *Forensics aid: the [[paraffin test]] is used in [[Forensic science|forensics]] to detect nitrates and nitrites on the hand of a shooting suspect | + | *Forensics aid: the [[paraffin test]] is used in [[Forensic science|forensics]] to detect nitrates and nitrites on the hand of a shooting suspect. |
| − | *Anti-ozonant agent: blends of paraffin and micro waxes are used in rubber compounds to prevent cracking of the rubber; the antiozonant waxes can be produced from synthetic waxes, FT wax, and Fischer Tropsch wax | + | *Anti-ozonant agent: blends of paraffin and micro waxes are used in rubber compounds to prevent cracking of the rubber; the antiozonant waxes can be produced from synthetic waxes, FT wax, and Fischer Tropsch wax. |
| − | *Mechanical thermostats and actuators, as an expansion medium for activating such devices.<ref>Bodén, Roger. [http://hermes.material.uu.se/~klas/Paraffin_lab_eng.pdf Paraffin Microactuator] | + | *Mechanical thermostats and actuators, as an expansion medium for activating such devices.<ref>Bodén, Roger. [http://hermes.material.uu.se/~klas/Paraffin_lab_eng.pdf Paraffin Microactuator] University of Uppsala. Retrieved December 2, 2007.</ref> |
| − | *"Potting" guitar pickups, which reduce microphonic feedback caused from the subtle movements of the pole pieces | + | *"Potting" guitar pickups, which reduce microphonic feedback caused from the subtle movements of the pole pieces. |
| − | *[[Wax bath]]s for [[beauty]] and therapy purposes | + | *[[Wax bath]]s for [[beauty]] and therapy purposes. |
| − | *Thickening agent in many Paintballs, as used by Crayola | + | *Thickening agent in many Paintballs, as used by Crayola. |
==See also== | ==See also== | ||
| Line 71: | Line 71: | ||
==References== | ==References== | ||
| − | * Hein, Morris, and Susan Arena. 2004. ''Foundations of College Chemistry''. Hoboken, NJ: John Wiley. ISBN 0471328189 | + | * Hein, Morris, and Susan Arena. 2004. ''Foundations of College Chemistry''. Hoboken, NJ: John Wiley. ISBN 0471328189 |
| − | + | * McMurry, John. 2004. ''Organic Chemistry''. 6th ed. Belmont, CA: Brooks/Cole. ISBN 0534420052 | |
| − | * McMurry, John. 2004. ''Organic Chemistry''. 6th ed. Belmont, CA: Brooks/Cole. ISBN 0534420052 | + | * Morrison, Robert T., and Robert N. Boyd. 1992. ''Organic Chemistry''. 6th ed. Englewood Cliffs, NJ: Prentice Hall. ISBN 0-13-643669-2 |
| − | + | * Olah, George A., and Árpád Molnár. 2003. ''Hydrocarbon Chemistry''. Hoboken, NJ: Wiley-Interscience. ISBN 0471417823 | |
| − | * Morrison, Robert T., and Robert N. Boyd. 1992. ''Organic Chemistry''. 6th ed. Englewood Cliffs, NJ: Prentice Hall. ISBN 0-13-643669-2 | + | * Solomons, T.W. Graham, and Fryhle, Craig B. 2004. ''Organic Chemistry''. 8th ed. Hoboken, NJ: John Wiley. ISBN 0471417998 |
| − | |||
| − | * Olah, George A., and Árpád Molnár. 2003. ''Hydrocarbon Chemistry''. Hoboken, NJ: Wiley-Interscience. ISBN 0471417823 | ||
| − | |||
| − | * Solomons, T.W. Graham, and Fryhle, Craig B. 2004. ''Organic Chemistry''. 8th ed. Hoboken, NJ: John Wiley. ISBN 0471417998 | ||
[[Category:Physical sciences]] | [[Category:Physical sciences]] | ||
[[Category:Chemistry]] | [[Category:Chemistry]] | ||
[[Category:Organic chemistry]] | [[Category:Organic chemistry]] | ||
| − | |||
{{credit|168552136}} | {{credit|168552136}} | ||
Revision as of 18:26, 2 December 2007
Paraffin is a common name for a group of alkane hydrocarbons with the general formula CnH2n+2, where n is the number of carbon atoms. The simplest paraffin molecule is that of methane, CH4, a gas at room temperature. Heavier members of the series, such as that of octane C8H18, appear as liquids at room temperature. The solid forms of paraffin, called paraffin wax, are from the heaviest molecules from C20 to C40. Paraffin wax was identified by Carl Reichenbach in 1830.
Paraffin, or paraffin hydrocarbon, is also the technical name for an alkane in general, but in most cases it refers specifically to a linear, or normal alkane—whereas branched, or isoalkanes are also called isoparaffins. It is distinct from the fuel known in Britain and South Africa as paraffin oil or just paraffin, which is called kerosene in much of the U.S., Australia and New Zealand.
Etymology
The name paraffin is derived from the Latin words parum, meaning "barely," and affinis, meaning "affinity." Thus the combination of words means "lacking affinity" or "lacking reactivity."
Wax
Paraffin wax is mostly found as a white, odorless, tasteless, waxy solid, with a typical melting point between about 47 °C and 64 °C. It is insoluble in water, but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents, but burns readily.
Pure paraffin wax is an extremely good electrical insulator, with an electrical resistivity of between and ohm meter.[1] 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.[2][3]
Paraffin wax (C25H52) is an excellent material to store heat, having a specific heat capacity of 2.14–2.9 J g–1 K–1 and a heat of fusion of 200–220 J/g.[4] The substance expands considerably when it melts and this property is exploited in thermostats for industrial, domestic and, particularly, automobile use.[5] For casting of metal and other materials, "investment casting waxes" are used, in which the paraffin wax is combined with several other materials to obtain the desired properties. Paraffin wax is not much used to make original models for casting, as it is relatively brittle at room temperature and usually cannot be cold-carved without excessive chipping and breaking. Soft, pliable waxes such as beeswax are preferred for these purposes.
In industrial uses, 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.
Liquid paraffin
Liquid paraffin, a mixture of heavier alkanes, has a number of names, including nujol, adepsine oil, alboline, glymol, medicinal paraffin, saxol, or USP mineral oil. It is often used in infrared spectroscopy, as it has a relatively uncomplicated IR spectrum. When the sample to be tested is made into a mull (a very thick solution), liquid paraffin is added so it can be spread on the disks to be tested. Liquid paraffin (medicinal) is used to aid bowel movement in persons suffering chronic constipation; it passes through the alimentary canal without itself being taken into the body, but it limits the amount of water removed from the stool. In the food industry, where it may be called "wax," it can be used as a lubricant in mechanical mixing, applied to baking tins to ensure that loaves are easily released when cooked and as a coating for fruit or other items requiring a "shiny" appearance for sale.[6]
Uses
Gaseous
- Fuels
Liquids
- Fuels
- Medicine (Laxative)
- Culinary
Paraffin wax
- Candle-making
- Coatings for waxed paper or cloth
- Food-grade paraffin wax:
- Shiny coating used in candy-making; although edible, it is nondigestible, passing right through the body without being broken down.
- Magic Shell
- Coating for many kinds of hard cheese, like Edam cheese.
- Sealant for jars, cans, and bottles
- Chewing gum additive
- Investment casting
- Anti-caking agent, moisture repellent, and dustbinding coatings for fertilizers.
- Agent for preparation of specimens for histology.
- Solid propellant for hybrid rocket motors.
- Emollient (moisturiser), in dermatology.
- Component of surfwax, used for grip on surfboards in surfing.
- Component of glide wax, used on skis and snowboards.
- Friction-reducer, for use on handrails and cement ledges, commonly used in skateboarding.
- Microwax food additive, a glazing agent with E number E905
- Forensics aid: the paraffin test is used in forensics to detect nitrates and nitrites on the hand of a shooting suspect.
- Anti-ozonant agent: blends of paraffin and micro waxes are used in rubber compounds to prevent cracking of the rubber; the antiozonant waxes can be produced from synthetic waxes, FT wax, and Fischer Tropsch wax.
- Mechanical thermostats and actuators, as an expansion medium for activating such devices.[7]
- "Potting" guitar pickups, which reduce microphonic feedback caused from the subtle movements of the pole pieces.
- Wax baths for beauty and therapy purposes.
- Thickening agent in many Paintballs, as used by Crayola.
See also
- Alkane
- Hydrocarbon
- Mineral oil
- Wax
Notes
- ↑ Electrical insulating materials National Physical Laboratory, UK. Retrieved December 2, 2007.
- ↑ Attenuation of fast neutrons: neutron moderation and diffusion. National Physical Laboratory, UK. Retrieved December 2, 2007.
- ↑ Rhodes, Richard. 1986. The Making of the Atomic Bomb. New York, NY: Simon and Schuster. ISBN 0-671-44133-7
- ↑ Specific Heat Capacity Dirac Delta Consultants Ltd, Warwick, England. Retrieved December 2, 2007.
- ↑ Wax-pellet thermostat United States Patent 4948043. Retrieved December 2, 2007.
- ↑ Mineral Oil (Food Grade) Food and Agriculture Organization of the United Nations; World Health Organization. Retrieved December 2, 2007.
- ↑ Bodén, Roger. Paraffin Microactuator University of Uppsala. Retrieved December 2, 2007.
ReferencesISBN links support NWE through referral fees
- Hein, Morris, and Susan Arena. 2004. Foundations of College Chemistry. Hoboken, NJ: John Wiley. ISBN 0471328189
- McMurry, John. 2004. Organic Chemistry. 6th ed. Belmont, CA: Brooks/Cole. ISBN 0534420052
- Morrison, Robert T., and Robert N. Boyd. 1992. Organic Chemistry. 6th ed. Englewood Cliffs, NJ: Prentice Hall. ISBN 0-13-643669-2
- Olah, George A., and Árpád Molnár. 2003. Hydrocarbon Chemistry. Hoboken, NJ: Wiley-Interscience. ISBN 0471417823
- Solomons, T.W. Graham, and Fryhle, Craig B. 2004. Organic Chemistry. 8th ed. Hoboken, NJ: John Wiley. ISBN 0471417998
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