Origin and Production. Vanillin is the principal aromatic substance of the vanilla, good vanilla beans containing about 2p.c. However, the value of vanilla cannot be judged alone by its vanillin content. The aromatic substances accompanying the vanillin are of great importance in judging the character of the vanilla aroma.
Composition. W. Busse2) suspected that the fruits of inferior vanilla species, the so-called vanillons, and also the fruits of Vanilla planifolia, Andr. (family Orchidaceae), cultivated in Tahiti contained piperonal in addition to vanillin. This supposition, however, could not be proved.
In order to study the aromatic principles of Tahiti vanilla apart from vanillin, H. Walbaum3) prepared the ethereal extract of 9,2 kilos of these beans. After the vanillin had been removed with sodium hydroxide solution, steam distillation of the residue yielded 7 g. of a light-brown oil having a pleasant characteristic odor. The boiling point of the oil, which was heavier than water, was between 105 and 118° (6 mm.). 6 g. of the oil distilled approximately at the boiling point of anisic alcohol, viz. at 115 to 118° (6 mm.). Artificial anisic alcohol from anisic aldehyde boiled at 117 to 118° under 5 mm. pressure. Fraction 115 to 118° of this vanilla oil also contained anisic aldehyde, the semicarbazone of which melted at 204°. With phenylisocyanate this fraction yielded an urethane which melted at 93°, and was identical with the urethane obtained from the artificial anisic alcohol. When oxidized with permanganate solution, this fraction yielded anisic acid, m. p. 180°. Besides, the presence of free anisic acid was demonstrated in the alkaline liquid from the extract. Piperonal, however, could not be detected. Whether anisic alcohol and anisic aldehyde are components of the aroma of the more valuable Bourbon vanilla has not yet been ascertained.
1) Apotheker Ztg. 16 (1901), 6.
2) Arbeiten a. d. Kaiserl. Ges. Amt 15 (1898 to 1899), 107.
3) Uber das Vorkommen von Anisalkohol und Anisaldehyd in der Tahiti-Vanille. Wallach-Festschrift. Goettingen 1909, p. 649; Report of Schimmel & Co. October 1909, 142.