Wax

Wax, by its origin, is divided into three groups: vegetable, animal, and mineral. Vegetable W. are called many substances of vegetable origin, which are found on leaves, stems, fruits, or inside various organs of plants. From a chemical standpoint, only a few can be classified as W., i.e., as esters of monatomic alcohols and monobasic acids with high molecular weight; most products called vegetable W. are fats, i.e., glycerides of acids, and are classified as W. only by their external appearance. The best known vegetable W. are: carnauba and palm W., and from the fats called wax,-Japanese and myrica. Carnauba wax covers in the form of dust the leaves of the palm Copernicia cerifera Mart., growing in South America (in Brazil). Its main mass consists of cerotic-myricyl ester C₂₅ H₅₁ COOC₃₀ H₆₁. Palm W. is obtained from the trunk of the palm Ceroxylon andicola, growing in the Andes of New Granada; in chemical composition it is close to beeswax. From the juice of Ficus cerifera Jung. (Sunda Islands) a wax-like mass is obtained, which is also apparently close in chemical composition to beeswax, but this W. is rarely found in European trade. Japanese W., cera Japonica, from the seeds of Rhus succedanea is not W., but a fat consisting mainly of glyceride of palmitic acid. Myrica W. is obtained from various species of Myrica, growing in the Azores, South Africa, Japan, and Java, and also contains glycerides of palmitic acid in its composition.--Animal W. is a product of the secretion of skin glands of many insects (Aphidae). In practical terms, beeswax has the greatest importance, Cera alba (Fig. VII). Beeswax is a yellowish substance from which bees build honeycombs; it has been known since ancient times: Greeks and Phoenicians were familiar with the bleaching of W.; from it they made candles, then flowers and fruits for decorating rooms. At present, W. is used, mainly, for medical, cosmetic, and religious purposes. Beeswax must be clearly distinguished from vegetable and mineral, or fossil, W., although there is much in common between them in certain physical properties and in insolubility in water, easy solubility in ether, as well as in richness of C and H. To obtain W., honeycombs are cut, honey flows out, and the honeycombs are pressed in presses or centrifuged. To separate the honey as completely as possible, W. is melted in hot water and allowed to cool: W. in the form of a solidified mass floats to the top. To purify it from impurities, it is melted on steam or on fire and filtered. The smell of W. depends on the smell of flowers. Yellow W. at ordinary temperature is brittle, with a fine-grained fracture. When chewed, it does not stick to the teeth. From the warmth of the hands, W. becomes soft and pliable; when heated, it melts at 63-65°; sp. gr. 0.960-0.970. W. is insoluble in water and cold alcohol; in ether, gasoline, chloroform, fatty and essential oils, W. is soluble. Beeswax should not contain mineral W., paraffin, foreign colors, stearic acid, resin, water, and various organic and mineral substances. After melting, it should give a completely homogeneous transparent yellow liquid. Its acid number is 18.7-20.5; ester number 72-76. The ratio of ester number to acid number should be 3.42-3.9. Wax consists mainly of cerotic acid C₂₅ H₅₁ COOH and palmitic-melissyl ester C₁₅ H₃₁ COOC₃₀ H₆₁, coloring and fragrant substances. W. is usually bleached in sunlight or with potassium dichromate, potassium permanganate with sulfuric acid, or with hydrogen peroxide, as well as with animal charcoal. Cera alba (Fig. VII), white or yellowish-white mass, rather brittle, not greasy to the touch, translucent in a thin layer; sp. gr. 0.967-0.973; melts at 63-65°. When heated, it dissolves in absolute alcohol, ether, essential and fatty oils, chloroform, gasoline, carbon disulfide. When melted, it gives an almost colorless liquid without sediment and foam. Acid number-18.7-22.4, ester number-73-76.7, ratio of ester number to acid number 3.42-3.9. Both yellow and white W. are used for preparing various preparations: as a constituent for pills, externally for ointments; Ungt. cereum or Cerat. simpl.; lipsticks-Cerat. labiale and others. For plasters: Empl. adhaesiv., Cantharid., Hydrargyri, Meliloti, Saponar. and others, as well as for bougies, for impregnating paper (charta cerata) or silk fabric (taffetas cerat.).-Mineral W., or ozokerite, is a dense residue after the evaporation and oxidation of petroleum. It is mined in large quantities in Galicia, on the island of Chelkenen in the Caspian Sea. Purified it is called ceresin and is used in many cases as a substitute for beeswax; it has wide application in technology; consists mainly of saturated hydrocarbons.