Citronella oil is obtained by distillation from the grass Cymbopogon Nardus, Stapf., formerly known as Andropogon Nardus (N.O. Gramineae), which is grown principally in Ceylon and the Straits Settlements. It occurs as a nearly colourless or pale yellow oil with a pleasant odour, having a specific gravity of 0.900 to 0.920 and an optical rotation usually from 0° to -15°. The addition of Russian petroleum or resin spirit reduces the solubility and decreases the acetylisable constituents.
Soluble in 80 per cent. alcohol (1 in 3 to 10) without turbidity.
Constituents.—It contains geraniol and citronellal, the latter predominating in the Java oil, which frequently has a lower specific gravity (not below 0.885), and contains 80 to 90 per cent. of total acetylisable constituents, whilst the Ceylon oil contains from 55 to 65 per cent. Camphene, dipentene, limonene, traces of linalool, borneol, methyl-heptenone, methyl-eugenol, and sesquiterpenes are also present.
Uses.—Citronella oil is chiefly used in soap perfumery and is also employed as a perfume for brilliantines and skin lotions.
The British Pharmaceutical Codex, 1911, was published by direction of the Council of the Pharmaceutical Society of Great Britain.