Paraffin

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Paraffin is a common name for a group of alkane hydrocarbons with the general formula C_nH_2n+2, where n is greater than about 20, discovered by Carl Reichenbach. It is distinct from the fuel known in Britain as paraffin oil or just paraffin, which is called kerosene in American English. Usage of the term varies in other countries, leading to confusion about which substance is being referred to. The solid forms of paraffin are called paraffin wax. Paraffin is also a 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. The name is derived from the Latin parum (= barely) + affinis with the meaning here of "lacking affinity", or "lacking reactivity").

Contents 1 Physical and chemical properties 2 Liquid paraffin 3 Uses 4 See also 5 References

[edit] Physical and chemical properties

It 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 is an extremely good electrical insulator, with an electrical resistivity of 10¹⁷ ohm meter. This is better than nearly all other materials except some plastics (notably teflon).

Paraffin wax (C₂₅H₅₂) is an excellent material to store heat, and has a typical heat capacity of .6 BTU/lb F to .66 BTU/lb F and a heat of fusion of 90-95 BTU/lb.

In industrial uses, it is often usefull 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[1], or polyethylene materials, such as C-16. The branched properties result in a modified paraffin with a higher viscosity, smaller crystalline structure, and modified functional properties.

[edit] Liquid paraffin

Liquid paraffin has a number of names, including nujol, mineral spirits, adepsine oil, alboline, glymol, liquid paraffin, 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 is also excellent for helping bowel movement in persons suffering chronic constipation.

It is also used as the fuel in Portable stoves because of its steady burning.

[edit] Uses

• Candle making
• Coatings for waxed paper or cloth.
• Food-grade paraffin wax
  • is used in some candies to make them look shiny. Although edible, it is nondigestible; it passes right through the body without being broken down.
  • Non-food grade paraffin wax can contain oils and other impurities which may be toxic or harmful.
  • Magic Shell
  • Coating for many kinds of hard cheese, like Edam cheese.
  • Sealing jars, cans, and bottles.
• A key component in wax used for investment casting.
• As anti-caking, moisture repellent, and dustbinding coatings for fertilizers.
• Preparing specimens for histology.
• Solid propellant for hybrid rocket motors.
• In dermatology, as an emollient (moisturiser).
• Surfing, for grip on surfboards as a component of surfwax.
• The primary component of glide wax, used on skis and snowboards.
• For use on handrails and cement ledges to dramatically reduce friction for rolling, otherwise known as aggressive in-line skating.
• Microwax[2] as a food additive, a glazing agent with E number E905.
• The paraffin test is used in forensics to detect nitrates and nitrites on the hand of a shooting suspect.
• A fire performance fuel.
• Blends of paraffin and micro waxes in rubber compounds as anti-ozonant agent, to prevent cracking of the rubber. The antiozonant waxes can today be produced from synthetic waxes, FT wax, and Fischer Tropsch wax.

Thermostats and actuators, as a temperature medium for activating such devices[3]

• "Potting" guitar pickups, which reduce microphonic feedback caused from the subtle movements of the pole pieces
• Paraffin, being rich in hydrogen, is used in some experiments with neutrons.

Impure mixtures of mostly paraffin wax are used in wax baths for beauty and therapy purposes.

Paraffin wax is not used much 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 modeling. For casting of metal and other materials, "investment casting waxes" are used, which use the paraffin in combination with several other materials to obtain the desired properties.

Paraffin Wax is also the wax used by Crayola, and is a thickening agent in many Paintballs

[edit] See also

• Paraffin oil
• Mineral oil
• Microcrystalline wax

[edit] References