Oleum Aurantii Florum (U. S. P.)—Oil of Orange Flowers.

Botanical name: 

Related entry: Aurantii Flores— Orange Flowers

"A volatile oil distilled from the fresh flowers of the bitter orange, Citrus vulgaris, Risso (Nat. Ord.—Rutaceae). It should be kept in well-stoppered bottles, in a cool place, protected from light"—(U. S. P.).
SYNONYMS: Oil of neroli, Essence of neroli.

Preparation and History.—This oil is obtained in the making of orange-flower water, the oil floating upon the surface of the fluid in small amounts. It is best when prepared from the petals rather than from the whole flower. As found in commerce it is usually adulterated with oil or essence of petit grain. The latter is the volatile oil of the leaves, shoots, and the young fruits of the Bigarade orange. The term oil or essence of petit grain, was at one time applied to the oil obtained by distillation from small, immature oranges, but is now referred to the oil produced as above stated.

Description.—"A yellowish or brownish, thin liquid, having a very fragrant odor of orange flowers, and an aromatic, somewhat bitter taste. Specific gravity, 0.875 to 0.890 at 15° C. (59° F.). Soluble in an equal volume of alcohol, the solution being neutral to litmus paper. If a little alcohol be poured on the surface of the oil, and the mixture gently undulated, a bright, violet fluorescence will usually be observed. In contact with a saturated solution of sodium bisulphite it assumes a handsome and permanent purplish-red color"—(U. S. P.). The oil has a slight right-handed optical rotation.

Chemical Composition.—Orange-flower oil contains an odorless stearopten, formerly called neroli camphor; it is a paraffin, melting at 55° C. (131° F., Pharmacographia). Tiemann and Semmler, in 1893, obtained by fractional distillation of the oil limonene, laevo-linalool, linaloyl acetate, and geraniol. Schimmel & Co., in 1894, discovered in the oil small quantities of anthranilic acid methyl-ester (NH2.C6H4.COOCH3), melting at 25° C. (77° F.), to the presence of which the fragrance and the fluorescence of the oil are due (see Report, April, 1899, p. 32). An artificial body, many times stronger than oil of neroli, and used quite extensively by soapmakers and perfumers, is on the market under the name nerolin. It is a white powder, soluble in fixed oil and alcohol, but not in water.

Uses.—Oil of orange flowers is used chiefly in manufacturing perfumes, and has been suggested for perfuming local applications.

King's American Dispensatory, 1898, was written by Harvey Wickes Felter, M.D., and John Uri Lloyd, Phr. M., Ph. D.