PARAFFIN

From Big Medical Encyclopedia

PARAFFIN (Latin parum is not enough affinis akin; it is called so because of inability to interact with the majority of chemical reagents) — mix of solid saturated hydrocarbons of preferential linear structure with number of carbon atoms from 9 to 40. Contains also isoparaffin, naphthenic and naftenoaromatichesky hydrocarbons.

The item is used in the national economy in the petrochemical, electrotechnical, light and food industry. High cleaning medical P. finds application in biology and medicine, napr, at gistol, for processing of fabrics. In pharmacy paraffin is used as aid, it is preferential as a sealant of bases of soft dosage forms. Big heat capacity, low heat conductivity, almost total absence of convection properties and ability during the hardening to allocate a large amount of heat cause P.'s use in physical therapy for treatment by heat at nek-ry diseases of internals and nevrol, frustration, and also in dental and cosmetic practice (see. Paraffin therapy ).

Items receive from oil, coal, peat and slate tar, and also from wood tar. Synthetic P. is received at catalytic synthesis from carbon monoxide and hydrogen in mix with fusible and liquid hydrocarbons, from to-rykh it then it is released.

Oil P. is allocated by winterizing from an oilstock (paraffinic distillate in ketone - benzene solution) with the subsequent department of the formed P.'s crystals on vacuum drum filters or by preferential adsorption of paraffinic hydrocarbons from fractions of oil by means of various adsorbents. P. received thus is exposed to cleaning with a chamois to - that, alkali, adsorbents, hydrotreating or cleaning with other methods.

The cleared P. represents colourless or white (on condition of removal of air from it) the firm weight having crystal structure on a break slightly fat to the touch, inodorous and taste. The item is water-insoluble also alcohol, is well ether-soluble, chloroform, gasoline, fatty and essential oils; t pl 50 — 57 °, t ° kip 350 — 560 °.

At a temperature over 100 ° P. easily is oxidized oxygen of air therefore the so-called oxidized P. containing an organic compound series is formed (like ant and stearin to - t, etc.).

The item has the adsorptive properties. In flux it can be saturated, e.g., with radon it. the lake gains radioactive properties.

Depending on contents in P. of petroleum oil distinguish high cleaning white, medical white, the technical cleared, crude and yellow Items.

Heat-retaining ability of P. is much higher, than at silt mud and peat, and concedes only a little to ozokerite (see). P.'s feature is its ability to decrease in volume during the cooling, to become elastic and to have a nek-swarm the squeezing (compression) effect on the subject fabrics.

It is shown that well cleared P. does not render on an organism of animals of ostrotoksichesky and cancerogenic action. However it must be kept in mind that in nek-ry, even high cleaning grades of P. 3,4 benzpyrene are found.



Bibliography: Parfyonov A. P. Physical remedies and resort factors, page 116, L., 1968; P e p e in e r-a pharynx A. N., Bogdanov N. F. and Groves of N of Yu. N. Production of paraffin, M., 1973.


N. V. Korobov.

Яндекс.Метрика