Chapter IV · (continued 2)

The French rosemary oil forms one of the ingredients of eau de Cologne and is used in other perfumery.

Rosewood oil or rhodium oil (oleum ligni rhodii), is obtained by distillation from the wood of the root and lower trunk of Convolvulus scopiarius and C. floridas, L., two plants indigenous to the Canaries. The waste falling off in the manufacture of rosewood beads is chiefly used for the purpose. The oil is of a pale yellow color becoming brown by age. It has a pleasant odor resembling in some slight degree the fragrance of the rose. It is sometimes used in cheap perfumery as a substitute for rose oil.

Sandal-wood oil (oleum ligni sandali) is distilled from the white West Indian or dark yellow East Indian sandal-wood (Santalum myrtifolium). For the purpose of distillation the wood is rasped as finely as possible. The oil obtained from the East Indian wood is the better and more valuable. It has a dark yellow to brown color and a pleasant intense, rose-like odor, while the West Indian oil is pale yellow and of a less agreeable odor. Both oils are very thickly-fluid. The quality and value of sandal-wood oil are best judged by the odor, an adulteration with cedar oil being readily detected thereby.

Sassafras oil (oleum ligni sassafras), from the bruised root of the sassafras tree, Sassafras officinale, natural order Lauraceæ. Sassafras is one of the most widely distributed trees of North America, being found in Canada, in all of the United States, east of the prairies, beyond the Mississippi, and in Mexico. The largest amount of oil distilled is within sixty miles of Baltimore, Md., which is the principal depot for its commerce.

Oil of sassafras varies in color from colorless to yellow and red. Its taste is pungent and aromatic, being agreeable to most persons. It has a pleasant odor resembling that of fennel, and is heavier than water, its specific gravity being 1.08 to 1.09. It is soluble in 4 to 5 parts of alcohol of 0.85 specific gravity, and consists of a mixture of various oils, among which is safrene (C₁₀H₁₆), a dextrorotatory terpene which boils between 311° and 314.6° F. By strongly cooling in a cold mixture, safrol, a crystallizing stearoptene of the composition C₁₀H₁₀O₂, is separated. Safrol is the chief constituent of sassafras oil. It is obtained in abundance by cooling, at a temperature of 13° F., the portion boiling between 442.4° and 455° F. It melts at 46.4° F., and at a medium temperature forms a colorless clear oil of pungent taste, characteristic odor, and specific gravity 1.104. When the crystals have been heated to above 158° F., they congeal only after remaining for weeks at a temperature below 32° F., but on being melted at 68° F., the fluid mass again congeals readily on cooling. The safrol is neutral, optically inactive, boils at 449.6° F., and is soluble in alcohol and ether. Sassafras oil is said to be frequently adulterated with oil of turpentine, which is, however, readily detected by the energetic reaction and by distilling a sample of the suspected oil.

Safrol is very suitable for perfuming ordinary soaps. It has in a still higher degree than camphor oil the property of removing the disagreeable odor of some fats, while at the same time it imparts to the soaps an aromatic, refreshing odor. As a rule 8 to 11 ozs. are used for 220 lbs. of soap; but if it shall at the same time serve for removing the disagreeable odor of low quality fats, especially those extracted with bisulphide of carbon or benzine, it is advisable to take 2.2 lbs., or still better, 4.4 lbs. for 220 lbs. of soap. In this case the safrol should be added to the fat after melting and before saponification and thoroughly mixed with it by stirring. An excellent perfume for ordinary soaps is a mixture of safrol and citronella oil, it being at any rate preferable to oil of mirbane.

The standard of value for safrol is its specific gravity, which should not be below 1.104 at 59° F. Specifically lighter kinds contain camphor oil and other impurities.

Thyme oil is obtained in Southern France and Spain by distillation from the flowering thyme, Thymus vulgaris, L. It is greenish-yellow to red (red thyme oil, oleum thymi rubrum), but by rectification becomes colorless (white thyme oil, oleum thymi album). Both oils are quite limpid and possess a strong thyme odor. The specific gravity of the red oil is 0.91 to 0.94, and that of the rectified oil 0.87 to 0.89. The oil prepared from the fresh plant shows, as a rule, a higher specific gravity than that from the dried plant. Thyme oil consists essentially of thymene (C₁₀H₁₆) besides some cymene (C₁₀H₁₄) and thymol (C₁₀H₁₄O), the latter forming an essential constitutent of the oil. Oils from which the thymol has been withdrawn occur in commerce. Pure thyme oil dissolves clear in every proportion in 90 per cent. alcohol; if such is not the case, adulteration with oil of turpentine is probable.

The oil distilled from the field thyme, Thymus serpyllum, L., is limpid, yellowish to gold yellow, and of specific gravity 0.89 to 0.91. Old oil is red or brown and no longer limpid. Good oil is soluble in every proportion in 90 per cent. alcohol and emits only slight vapors when brought in contact with iodine. It consists largely of thymene and cymene, and contains a few per cent. of phenol-like bodies.

Turpentine, oil of.—Under the general name "oil of turpentine" are comprised the volatile oils obtained by distillation from the resins or other portions of different species of the pine. There is a large number of these oils, the most important ones of which shall here be mentioned, though but a few are of interest to the perfumer.

Austrian oil of turpentine, from Pinus laricio, Poir.—It is colorless or yellowish, transparent; specific gravity, 0.864; boiling point, 311° to 314° F.; turns polarized light to the left; soluble in 6 parts 90 per cent. alcohol. When rectified it has a specific gravity of 0.862, and is soluble in 7 parts of 90 per cent. alcohol.

German oil of turpentine, from Pinus sylvestris, P. abies, P. vulgaris, P. picea, and P. rotundata, resembles the former; specific gravity, 0.860 to 0.870; boiling point, 311° to 320° F.; turns polarized light to the left. When rectified it is soluble in 7 parts of 90 per cent. alcohol.

French oil of turpentine, from French turpentine of Pinus maritima.—It is colorless or faint yellowish; specific gravity, 0.860; boiling point, 313° to 315° F.; turns polarized light to the left; odor peculiar; taste burning. With 7 parts of 90 per cent. alcohol it gives a clear solution.

Venetian oil of turpentine, from Venice turpentine of Larix decidua, Mill., is laevorotatory and resembles the preceding, but has a more agreeable odor. Venice turpentine is mostly obtained in Southern Tyrol and in Piedmont, and yields 18 to 25 per cent. of oil.

American oil of turpentine, from American turpentine of Pinus australis, Mich., and P. Taeda, L.—It resembles French turpentine, but turns polarized light to the right. Specific gravity, 0.864; boiling point, 302° to 312.8° F.

Pine oil (oleum abietis) is obtained by distilling with water the leaves or green cones of Pinus picea, L., Abies pectinata, D. C. Its odor is much finer than that of ordinary oil of turpentine. It is soluble in 7 parts of 90 per cent. alcohol.

Dwarf pine oil, Krummholz or Latschenoel (oleum pini pumilionis), is obtained by distilling the young tops and cones of Pinus pumilio with water. It has an agreeable odor, reminding one of juniper; specific gravity, 0.865; boiling point, 338° F. The oil is laevorotatory and soluble in 12 to 15 parts of 90 per cent. alcohol.

Pine-leaf oil is obtained by distilling the leaves of Pinus sylvestris or P. abies by means of steam. It is dextrorotatory; has a fine aromatic odor; boiling point, 320° F.; specific gravity, 0.875 to 0.876.

Templin oil (Kienoel) (oleum pini, ol. templinum) is obtained chiefly in some sections of Switzerland and Tyrol by distilling the wood, branches, leaves, cones, etc., with water. It has a lemon-like odor; specific gravity, 0.860 to 0.880; boiling point, 320° to 327° F., and is laevorotatory.

Balsam-pine oil (oleum abietis canadensis) is obtained in Canada from the branches of Abies balsamea, D. C. It has a slightly yellowish color, a very agreeable and refreshing odor; specific gravity, 0.902; boiling point at 320° to 330.8° F., and turns polarized light to the right.

Of the different varieties of oil of turpentine mentioned only pine oil and dwarf pine oil are used in perfumery.

Oils of turpentine must be kept carefully protected from light and air. When badly kept they gradually become resinous with formation of formic and acetic acids. When exposed to the air oil of turpentine absorbs ozone; with iodine it detonates violently. When brought in contact with a mixture of concentrated sulphuric acid and nitric acid it ignites.

Verbena, oil of, from the lemon verbena, Aloysia citriodora, Hooker. The plant is cultivated in the gardens of Grasse. The oil is extracted from the leaves by distillation in August, but on account of its high price is almost out of market, it being everywhere substituted by the oil of lemon grass, Andropogon citratus.

Violet, oil of.—The perfume of the violet, Viola odorata, natural order Violaceæ, is due to a volatile oil of a green color and of such a penetrating odor as to cause headache; it acquires the agreeable odor of the violet only by strong dilution. The violet farms from whence the flowers are procured for the production of the oil, are very extensive at Nice and in the neighborhood of Florence. The oil is only obtained by the absorption process, all other methods to procure it having failed up to this time. It is scarcely obtainable in commerce, as the French manufacturers, who prepare the greater part of it, use the very small yield for manufacturing fine perfumery.

Vitivert or vetiver oil (oleum iva ranchusa) from the so-called cuscus, the rhizome of an Indian grass, Anathereum muricatum. The oil is obtained by distillation, either from the fresh root in India, or from the imported dried root in Europe. The yield is very small. The oil is thickly-fluid, of a red-brown color, and has an intense, but agreeable odor very much like that of oil of orris root. Like the latter, it possesses the valuable property of diffusing a lasting perfume. Its value can only be judged by the odor, and hence it should only be purchased from a thoroughly reliable firm.

Wintergreen oil (oleum gaultheriæ) is obtained by distillation from the wintergreen, Gaultheria procumbens, a plant common in North America. It is thickly fluid, yellowish green to gold yellow, of a sweetish, aromatic, pungent taste and penetrating, narcotic odor, which becomes agreeable only by strongly diluting the oil. By rectification the oil becomes entirely colorless. Its specific gravity is 1.170 to 1.190 (according to Gladstone, 1.142). It is sparingly soluble in water, but readily so in alcohol, ether, chloroform, etc. The aqueous or dilute alcoholic solution is colored deep violet by ferric chloride.

Wintergreen oil boils at 392° F.; the boiling point, however, soon rises to 431.6° F., when it remains constant. Between 392° and 428° F. a terpene (C₁₀H₁₆) constituting about 1/10 of the oil distils off; the rest corresponds to the composition C₈H₈O₃; it is methyl salicylate

=C₆H₄┌OH └CO.OCH₃.

Wintergreen oil is also obtained by distillation from Gaultheria punctata and Gaultheria leucocarpa. An oil, very closely resembling wintergreen oil, is in this country distilled from the young shoots of the American species of birch, Betula lenta, variously called sweet birch, black birch, cherry birch, and mountain mahogany. According to Procter, the oil does not exist in the birch but is formed by the action of the water upon an odorless body, called gaultherin, which is converted into volatile oil by the reaction of another substance analogous to emulsin. Hence the formation of oil is similar to that of oil of bitter almonds. To obtain the oil from Betula lenta, the material is chopped up and placed in the still, as much as this will hold, a sufficient quantity of water being then added to fill the still about one-third full. The still is generally permitted to remain in this condition over night, a fire is made in the morning and distillation proceeds nicely. The manufacture of birch oil is carried on at quite a large scale by Mr. A. H. Seidle, of Middleport, Schuylkill County, Pa.

Methyl salicylate may also be artificially prepared by heating a mixture of methyl alcohol, sulphuric acid and salicylic acid whereby at first methyl-sulphuric acid is formed which is then converted into methyl ether and sulphuric acid:—

┌OH ┌OCH₃

SO₂┤+ CH₃OH = SO₂┤+ H₂O

└OH └OH

┌OCH₃┌OH

SO₂┤+ C₆H₄┤=

└OH└COOH

┌OH┌OH

C₆H₄┤+ SO₂┤

└CO.OCH₃└OH.

Etherification succeeds without difficulty, it being sufficient to heat the mixture for some time and then pour it into water whereby the ether separates as a heavy layer of oil. After washing with water distil in a direct current of steam. The ether thus obtained is as clear as water and, as regards its other properties, does not differ from the naturally occurring oil. This artificial wintergreen oil is now much used for perfuming purposes.

Wintergreen oil is said to be frequently adulterated with sassafras oil which is also specifically heavier than water. If, according to Hayer, 5 drops of the oil in a test-tube be mixed with 10 drops of crude concentrated nitric acid, a deep blood-red fluid results in one minute if oil of sassafras is present. In the course of another minute, the fluid separates a brown resinous mass. Pure oil, on the other hand, is but little altered.

According to P. MacEwan the adulteration of wintergreen oil with camphor oil is carried on at a large scale. The presence of camphor oil may be recognized by the specific gravity, 0.900, while that of pure wintergreen oil is, on an average, 1.18. A crude test—which is, however, readily executed—is as follows: Stir a few drops of the suspected oil in water. If pure, the oil in a few seconds sinks to the bottom, but if it contains camphor oil several minutes elapse before it deposits, and there is time to observe that the particles of oil assume different forms, but not a globular one.

Ylang-Ylang oil (oleum unonæ) is obtained by distilling the flowers of Unona odoratissima, indigenous to the Philippine Islands, the Straits of Malacca, and Indian Archipelago. The oil is colorless to yellowish. Its color and specific gravity, however vary very much, according to the season of the year in which it is prepared, the oil distilled in the cold season being more colorless and limpid than that produced in the warm season. The oil has an exquisite odor, partaking of the jasmine and the lilac, and is used in the manufacture of the finest perfumery. Various kinds are found in commerce, that marked "Sartorius" being preferred.

The difference in quality of the many kinds of oil found in commerce is chiefly due to the method of preparation and the selection of the flowers, which possess the finest aroma when freshly gathered. In distilling, the first light volatile portions passing over have an incomparable perfume, while the oil distilling over later on possesses an insipid odor. Hence the manufacturer, who only obtains the first portions, will furnish the finest quality of oil, and it is this method of preparation which has gained the "Sartorius" oil its high reputation. While according to Schimmel & Co.'s report, 220 lbs. of fresh ylang-ylang flowers yield 2.64 lbs. of oil, Sartorius for the preparation of his fine oil distils off only about half the quantity.

Conanga oil is a poorer quality of ylang-ylang oil, obtained from the same plant. Two varieties are distinguished in commerce, viz: the Javanese and Indian. The Java oil is the best, and may be used where ordinary qualities of ylang-ylang oil will do. According to Schimmel & Co.'s report the cheaper Indian oil is very resistant and durable in soaps, especially when combined with licari or linaloë oil.