paraffin(redirected from paraffin embedding technique)
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paraffin,white, more-or-less translucent, odorless, tasteless, waxy solid. It melts between 47°C; and 65°C; and is insoluble in water but soluble in ether, benzene, and certain esters. Paraffin is unaffected by most common chemical reagents but burns readily in air. Obtained from petroleum during refining, it is used in candles, for coating paper, and for various other purposes. Chemically, paraffin is a mixture of high-molecular-weight alkanesalkane
, any of a group of aliphatic hydrocarbons whose molecules contain only single bonds (see chemical bond). Alkanes have the general chemical formula CnH2n+2.
..... Click the link for more information. , i.e., saturated hydrocarbonshydrocarbon
, any organic compound composed solely of the elements hydrogen and carbon. The hydrocarbons differ both in the total number of carbon and hydrogen atoms in their molecules and in the proportion of hydrogen to carbon.
..... Click the link for more information. with the general formula CnH2n+2, where n is an integer between 22 and 27.
a petroleum product that consists of a mixture of predominantly straight-chain alkanes that range from nine to 40 carbon atoms in length. Isoparaffin, cycloparaffin, and naphtheno-aromatic hydrocarbons are also found in paraffin. Solid paraffin, which melts between 45° and 70°C, is primarily obtained from oily distillates of paraffin-base petroleum. In this process, the crude mixture of paraffin and oil is dewaxed by crystallization. Paraffin is also extracted from petroleum fractions through the selective adsorption of straight-chain alkanes by zeolites. Liquid paraffin, which boils off between 180° and 360°C, is obtained during the urea dewaxing of certain petroleum products. Commercial paraffin undergoes preliminary adsorbent processing and is then purified by other methods.
Because of its chemical neutrality and various other properties, paraffin is widely used in the food industry, in medicine, in the manufacture of cosmetics and perfumes, and as an insulating material in electrical engineering. It also serves as a raw material for the petrochemical industry in the manufacture of such substances as higher fatty acids, higher alcohols, and detergents. Several brands of paraffin are currently available, including fully refined paraffin, semirefined paraffin, and medicinal paraffin.
REFERENCEPereverzev, A. N., N. F. Bogdanov, and lu. N. Roshchin.
Proizvodstvo parafinov. Moscow, 1973.
I. P. LUKASHEVICH