|
PARAFFIN
- For the British meaning of Paraffin, see Kerosene
Paraffin is a common name for a group of alkane hydrocarbons with the general formula CnH2n+2, where n is greater than about 20, discovered by Carl Reichenbach. In the U.S.A. the fuel known in most of the world as paraffin oil (or just paraffin) is called kerosene. 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, while branched, or isoalkane are also called isoparaffins. The name is derived from the Latin parum (= barely) + affinis with the meaning here of "lacking affinity", or "lacking reactivity").
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 65 °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 a electrical resistivity of 1017 ohm meter. This is better than nearly all other materials except some plastics (notably teflon).
Liquid paraffin
Liquid paraffin has a number of names, including nujol, mineral spirits, adepsine oil, alboline, glymol, liquid paraffin, medicinal paraffin, paraffin oil, 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. Jet fuel is a type of paraffin oil (or "kerosene" in US English). Liquid paraffin is also excellent for helping bowel movement in persons suffering chronic constipation.
Uses
- Candlemaking
- Coatings for waxed paper or cloth.
- Coating for many kinds of hard cheese, like Edam cheese.
- 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.
- Sealing jars, cans, and bottles.
- 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.
- Microwax as a food additive, a glazing agent with E number E905.
- The paraffin test is used in forensics to detect granules of gunpowder in 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.
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.
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.
See also
References
|