The TRUE WAXES L. WILSON GREENE
A
STUDY of the wax literature shows that some confusion exists in the nomenclature and classification ol these substances. The term "wax" in the broadest sense is used to designate plastic materials which resemble beeswax in physical properties. In Greek mythology and in the various writings of
antiquity there are several references to wax and i t is generally agreed that these are concerned with beeswax alone. Thus i t is easy to understand that, when new products having properties similar to beeswax were discovered, they should be termed waxes also. As a result we have today a number of commercially im-
portant substances called waxes which are not related chemically to beeswax a t all, although they may have "waxy" properties. From a chemical standpoint, waxes are defined as esters of fatty acids with monohydric alcohols of high molecular weight. They are distinguished from fats which are esters of fatty acids with trihydric alcohols (usually glycerol) of low molecular weight, and it might be added that the so-called fixed or fatty oils are in reality fats which are liquid a t the ordinary temperature. The more important substances that are erroneously called waxes are as follows: Bayberry wax.-A fat derived from the wax myrtle, Myrica cerifera. The substance is also known as myrica wax, myxtle wax, and bayberry tallow. Ceresin wax.-A mixture of solid hydrocarbons obtained by refining ozokerite (ozocerite), a native paraffin. In the older literature it is sometimes spelled "cerasin." It should not be confused with cerosin, a name occasionally applied to cane wax; with cerasin from brain tissue; with cerasein, a resin from wild cheny bark; or with sericin,'a gelatinous substance obtained from natural silk. Earth wax.-This term is often applied to ceresin and sometimes to ozokerite. Mineral wax.-A term often employed to designate naturally occurring paraffin or ozokerite. Japan wax.-A fat obtained from the berries of Rhus succedanea and various other species of sumach. I t is also called berry wax, sumach wax, and japan tallow. The product should not be confused with Japanese beeswax. Parafin wax.-A mixture of solid hydrocarbons obtained from petroleum or occurring naturally. There are numerous references in the literature to amorphous wax, tail wax (wax tailings), residue wax, slack wax, and scale wax. These all pertain to paraffin separated in various phases of petroleum refining. There are several natural substances that are true waxes which, nevertheless, are not designated as such. These are described as follows. Arctic sperm oil.-A liquid wax from the bottlenose whale, Hyperoodon sp. I t is also called bottlenose oil and doegling oil. The ordinary whale oil of commerce is a fat. Dolphin oil.-A mixture of liquid wax and fat from the dolphin, Delphinus delphin, Lin. Jojoba oil.-A liquid wax from the seeds of the plant, Simmondsia californica. Mutton bird oil.-A liquid wax from the stomach of the mutton bird, or petrel, Aestrelata lessoni. Sperm oil.-A liquid wax from the sperm whale, Physeter macrocephalus. Also known as spermaceti oil and cachalot oil. Spermaceti, or cetaceum, is a solid wax obtained from the head cavity of this whale. Wool fat.-A semisolid wax from the wool of the sheep, containing wax alcohols, free fatty acids, and cholesterol. The crude product has a variety of names: wool grease, Yorkshire grease, degras, moellon degras,
and, occasionally, snint. The term degras is also applied to fats such as cod oil, used in treating leather, while suint is actually the dried perspiration of the animal found on the wool. Refined wool wax is called lanolin, lanoline, and lanocerin. Several years ago it was customary to divide the waxes into two main groups, the liquid and the solid waxes. Each of these groups was further separated into animal and vegetable waxes. A better scheme is to classify them according to source, regardless of whether they are normally liquid or solid. Such a classification is given below with a few examples listed for each group. (A). Animal waxes (1) Insect (beeswax, Chinese insect wax, shellac wax). (2) Terrestrial (wool wax, mutton bird wax). (3) Marine (Arctic sperm wax, sperm wax, spermaceti). j (B). Vegetable waxes Leaf, stem, and bark (carnauba wax, candelilla wax, cane wax, palm wax). (1) Fiber (cotton wax, flax wax, esparto wax, hemp wax). (2) Flower (rose wax, jasmine wax). (3) Fruit (apple wax, pomegranate wax). (4) Latex (cow tree wax, fig wax). (5) Seed (coffeewax, jojoba wax). (6) Bacillus (tubercle bacillus wax). (7) Fossil (montan wax, peat wax). It will be noted that montan and peat waxes are classified as fossil vegetable waxes. They are found in lignite, peat, and coal. Some authors call them mineral waxes but an examination of their chemical nature shows them to be entirely unrelated to naturally occurring paraffin and ozokerite, which have likewise been termed mineral waxes. There may be some objection to the inclusion of tubercle bacillus wax under this scheme. I t is more of the nature of a complex phosphatide but it does contain typical wax acids. Someone has proposed that the fatty acid esters of the sterols, such as cholesterol oleate, be classed as waxes. By definition this could be done, even though the sterol portion of the compound has a terpene structure. The proposal, however, has not been adopted, and these substances are omitted from the classification scheme given above. The study of waxes offers many points of interest. Why liquid waxes occur in two species of whales, two of fish, one bird, and the seeds of a plant is an intriguing question, especially when we consider that the lipides of other whales, fish, birds, and plant seeds are mostly fats. The plant waxes are widely distributed throughout the vegetable kingdom but much remains to be learned regarding the relation of chemical composition of waxes to plant metabolism and habitat. New technical applications of the natural and synthetic waxes are being constantly developed and the literature of the subject is growing larger every year. It is hoped that the present attempt to elucidate the subject of waxes will be of assistance to those who may wish to investigate wax chemistry more fully.
