Benzyl Acetate, the ester obtained from benzyl alcohol and acetic acid. This has a very strong and somewhat coarse, penetrating odour, distinctly resembling jasmine. Its specific gravity at 15° C. is 1.062-1.065; refractive index at 20° C., 1.5020; and it should contain at least 97-98 per cent. ester, calculated as benzyl acetate.
Citral, the aldehyde occurring largely in lemon-grass and verbena oils, also to a less extent in lemon and orange oils, and possessing an intense lemon-like odour. It has a specific gravity at 15° C., 0.896-0.897, is optically inactive, and should be entirely absorbed by a hot saturated solution of sodium bisulphite.
Citronellal, an aldehyde possessing the characteristic odour of citronella oil, in which it occurs to the extent of about 20 per cent., and constituting considerably over 90 per cent. of eucalyptus citriodora oil. Its specific gravity at 15° C. is 0.862; refractive index at 20° C., 1.447; optical rotation, +8° to +12°; and it should be entirely absorbed by a hot saturated solution of sodium bisulphite.
Coumarin, a white crystalline product found in Tonka beans, and prepared synthetically from salicylic acid. It has an odour resembling new-mown hay, and melts at 67° C.
Geraniol, a cyclic alcohol, occurring largely in geranium, palma-rosa, and citronella oils. Its specific gravity at 15° C. is 0.883-0.885; refractive index at 20° C., 1.4762-1.4770; it is optically inactive, and boils at 218°-225° C.
Heliotropin, which possesses the characteristic odour of heliotrope, is prepared artificially from safrol. It crystallises in small prisms melting at 86° C.
Hyacinth.—Most of the articles sold under this name are secret blends of the different makers. Styrolene has an odour very much resembling hyacinth, and probably forms the basis of most of these preparations, together with terpineol, and other artificial bodies. The properties of the oil vary considerably for different makes.
Ionone, a ketone first prepared by Tiemann, and having when diluted a pronounced violet odour. It is prepared by treating a mixture of citral and acetone with barium hydrate, and distilling in vacuo. Two isomeric ketones, α-ionone and β-ionone, are produced, the article of commerce being usually a mixture of both. The two ketones have the following properties:—
Alpha-ionone.—Specific gravity at 15° C., 0.9338; refractive index at 16.5 C., 1.50048 (Chuit); optically it is inactive.
Beta-ionone.—Specific gravity at 15° C., 0.9488; refractive index at 16.8° C., 1.52070 (Chuit); optically it is inactive also.