This section is from the book "A Text Book Of Materia Medica, Being An Account Of The More Important Crude Drugs Of Vegetable And Animal Origin", by Henry G. Greenish. Also available from Amazon: A Text Book of Materia Medica : Being an Account of the More Important Crude Drugs of Vegetable and Animal Origin.
Wax is a material secreted by the bee on the under surface of its body, and employed to form the walls of the cells of the honeycomb. After the separation of the honey the residual wax is purified by melting with water, separating, and straining; it then forms the yellow wax of commerce. White wax is obtained by exposing thin bands of yellow wax for several weeks to the action of air and sunlight, occasionally watering it, and if necessary remelting, to promote the bleaching by exposing fresh surfaces to these influences. Yellow wax is also largely bleached by chemical means, such as the action of chromic acid.
Wax is imported from Jamaica, California, Chili, Egypt, Syria, Madagascar, Morocco, etc.
Yellow wax is a yellowish or brownish yellow solid, with an agreeable, honey-like odour, breaking with a granular fracture, and not unctuous to the touch. It is readily and entirely soluble in hot oil of turpentine, partially soluble in alcohol. It is practically insoluble in water and in boiling aqueous solution of sodium hydroxide, the two latter liquids after filtration being neither turbid, nor becoming turbid on the addition of hydrochloric acid.
The specific gravity of wax varies from 0.958 to 0.970; melting-point from 61° to 64°; refractive index at 80° 1.4380 to 1.4420. These limits are narrow, and the specific gravity and melting-point often afford very valuable information as to the purity of the sample under examination.
Beeswax consists principally of melissyl palmitate (myricin), with which is associated free cerotic acid, an aromatic body cerolein, and probably melissyl stearate.
Cerotic acid, C25H51COOH(?), is an acid belonging to the formic acid series the formula of which is not definitely established. It crystallises from alcohol in granular colourless crystals melting at 78°-79°. Ceryl cerotate, C25H5COOC26H53, occurs in Chinese wax, the produce of Coccus cerifera, Fabricius (C. pela, Westwood), and in wool fat.
Melissyl palmitate, C15H31COOC30H61, is the palmitic ester of melissyl alcohol; the latter occurs in colourless crystalline needles melting at 85°.
Paraffin and bodies belonging to this class are not attacked by hot, concentrated sulphuric acid, whereas beeswax is entirely destroyed; hence if 5 grammes of beeswax are heated for fifteen minutes with 25 grammes of concentrated sulphuric acid to 160°, and the mixture afterwards cooled, rinsed with alcohol and then extracted with ether, the latter solution should leave no appreciable solid residue on evaporation. A better test for paraffin (and other foreign waxes) is Weinwurm's which is performed as follows:
Saponify 5 gm. of the wax by boiling it with 15 c.c. of N/1 alcoholic solution of potassium hydroxide and 15 c.c. of absolute alcohol, evaporate to dryness, dissolve the residue in 20 c.c. of glycerin on a water-bath, and add 80 c.c. of boiling distilled water; a clear, or at least translucent, solution should be obtained.
Resin (colophony) would be readily dissolved by cold alcohol, in which genuine beeswax is sparingly and only partially soluble.
Soap would be removed by hot water, and the filtrate would become cloudy when acidified with hydrochloric acid from separation of the fat acid.
Stearic acid, colophony, Japan wax (obtained from the fruits of various species of Rhus (N.O. Anacardiaceoe), tallow, and all fats easily saponified, would be converted into soap by the action of boiling aqueous solution of sodium hydroxide which does not appreciably attack wax; the solution after separation and filtration would then be rendered turbid by hydrochloric acid from separation of the free fat acids.
Starch (which might be added to white wax) would be detected by boiling with water and applying the iodine test. Inorganic substances, such as kaolin, would be detected in the ash, and by their insolubility in oil of turpentine.
Foreign colouring matters may be detected by boiling the wax with alcohol for five minutes, cooling thoroughly for several hours and filtering; the filtrate should be almost colourless.
Further information respecting the purity of wax may be obtained by determining the acid value, which should not be less than 17.9 and the ester value (69.6 to 76.1) as directed in the Pharmacopoeia; the ratio of the acid value to the ester value should be about 1 to 4.
Japan Wax is the fat secreted in the mesocarp and cotyledons of the fruit of Rhus succedanea, Linne, and other species of Rhus (N.O. Anacardiaceoe), Japan. The fruits are husked between millstones, crushed and boiled with water; the fat is skimmed off, purified by melting and straining, and then poured into moulds. It is a firm, white solid, consisting chiefly of palmitic acid and its glyceride. Melting-point about 50° to 56°. It is not a true wax, but a fat.
Carnauba Wax is the wax secreted on both surfaces of the leaves of Copernicia cerifera, Martius (N.O. Palmoe), South America. The leaves are dried and spread on cloths; the wax is separated by brushing and beating, and then melted and poured into moulds. Consists chiefly of melissyl (myricyl) cerotate, melissyl alcohol, carnaubic acid. Melting-point 83° to 86°. Used in candle making, boot polishes, etc.
Chinese Insect Wax, Pela, is produced by Coccus cerifera, Fabricius (N.O. Hemiptera) on the twigs of Ligustrum lucidum (N.O. Oleaceae) or Fraxinus chinensis, Roxburgh (N.O. Oleaceoe). The bark with its coating of wax is stripped from the tree, the wax melted in hot water, skimmed off, purified by re-melting and poured into moulds; colourless or pale yellowish, crystalline, almost odourless and tasteless, melts at about 81° to 83°; consists almost entirely of ceryl cerotate.