Origin and Production. The fragrant flowers of Polianthes tuberosa, L. (family Amaryllidaceae), which is native to Central America and which is cultivated extensively in southern France1), yield upon distillation no essential oil but a product of an unpleasant odor. In order to obtain the perfume as completely as possible, it is necessary to apply the enfleurage process (see vol. I, p. 258) which has been used in southern France for a long time. According to A. Hesse2), to whom we are indebted for very interesting comparative experiments, 1000 kg. of tuberose blossoms yielded 801 g. of volatile oil to the fat used in the enfleurage process. The flowers removed from the fat yielded, upon extraction and subsequent distillation with steam, an additional 78 g. of oil. The direct extraction (see vol. I, p. 247) of the same amount of flowers yielded only 56 g., and at the beginning of the flower harvest only 36 g. of oil. To this, however, there should be added 10 g. of oil obtained from subsequent distillation of the extracted flowers. Hence enfleurage yields 13 times as much oil as the extraction method. It may be assumed, therefore, that during the period of enfleurage the tuberose blossoms develop 12 times the amount of volatile oil originally contained in the flowers.
Properties. The oil obtained by Hesse from tuberose flowers by means of the extraction method with petroleum ether had the following properties: d15o1,007; aD - 3°45'; A.V. 22; S. V. 224; it contained 1,13 p.c. of anthranilic acid methyl ester. An oil obtained from the enfleurage fat, that had been obtained at different times, revealed the following properties: d15o 1,009 to 1,035; aD (1 determination) - 2°30'; A.V. (1 determination) 32,7; S. V. 243 to 280; methyl anthranilate content 3,2 to 5,4 p.c. The oil referred to above obtained by extraction and steam distillation of the waste flowers of the enfleurage process, showed the following constants: d15o1,043; aD - 3°21'; S.V.225,4; methyl anthranilate content 2 p.c.
1) Comp. L. Mazuyer, Production et culture de Tubereuse. Journ. Parfum. et Savonn. 21 (1908), 195.
2) Berl. Berichte 86 (1903), 1459.
Composition. The oil from the flowers of tuberose was first examined by A. Verley1). He isolated from the oil about 10 p. c. of a substance which he designated tuberone, and which he supposed to be a ketone of the formula C13H20O. Schimmel &Co.'-') tried in vain to isolate a ketone from the corresponding fraction of an oil obtained from a floral extract (Essence concrete). Upon oxidation of this oil which, because of its fluorescence, was supposed to contain anthranilic acid methyl ester with permanganate, a readily volatile oil remained unattacked. Upon saponification this yielded benzoic acid (m. p. 122°; analysis of silver salt), hence it was regarded as methylbenzoate.
Hesse3), who worked with larger amounts, succeeded in definitely demonstrating the presence of methyl anthranilate, and isolated the stable ester of benzoic acid by oxidation with potassium permanganate solution.
The mixture of esters not attacked by the potassium permanganate distilled between 199 and 240°. Upon saponification benzoic acid and benzyl alcohol could be isolated. Hence a part of the ester mixture may be regarded as benzyl benzoate. The presence of methyl benzoate, which Schimmel & Co. suspected in this mixture, is questioned by Hesse who is of the opinion that, if it is present at all, the quantity is infinitesimal.
Nevertheless it is remarkable that the mixture of esters resulting upon oxidation is relatively so volatile. Hesse records the boiling temperature of the first half of the mixture as from below 199 to 240°, and that of the other half as above 240°. The boiling point of benzyl benzoate, however, is 324°. It follows that lower boiling esters must be present and therefore the presence of methylbenzoate (b. p. 199 to 200°) is not at all improbable.
Moreover by treating the oil with phthalic anhydride, Hesse isolated an alcohol which, judging from its boiling temperature, viz., 206 to 214°, and its other constants consists chiefly of benzyl alcohol. Hence this alcohol also occurs in the free state in the oil of tuberose flowers.
1) Bull. Soc. chim. III. 21 (1899), 307.
2) Report of Schimmel & Co. April 1903, 74.
3) Loc. cit.
In the oil from the pomade, Hesse demonstrated the occurrence of methyl salicylate which could not be detected in the oil obtained by extraction.