The constituents of an essential oil of rue / by Frederick B. Power and Frederic H. Lees. Methyl beta-methylhexyl ketone / by Frederic H. Lees.

Power, Frederick B. (Frederick Belding), 1853-1927

Date:: [1902]

Credit: The constituents of an essential oil of rue / by Frederick B. Power and Frederic H. Lees. Methyl beta-methylhexyl ketone / by Frederic H. Lees. Source: Wellcome Collection.

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$and the separated oil taken up with ether. The ethereal solution was washed, dried quickly with calcium chloride, and the ether removed. The alkaline liquid was acidified, distilled with steam, and the dis¬ tillate neutralised with sodium carbonate, concentrated, acidified, and extracted with ether. From the ethereal solution an appreciable quantity of a light yellow, pungent liquid was obtaiued. This distilled almost completely below 120 \ leaving a very small amount of an acid of higher boiling point in the flask. Identification of Acetic Acid. 1 he portion oi acid which distilled below 120} was converted into its barium salt, and from a portion of this a silver salt was prepared. On analysis : 0-2208 gave 0T426 Ag. Ag = 64*6. requires Ag = 64‘7 per cent. The higher boiling portion of volatile acid was dissolved in a little dilute aqueous ammonia, decolorised by animal charcoal, and converted into a silver salt, which was for the most part insoluble in hot water. On analysis: 0-0704 gave 0-0304 Ag. Ag = 43-2 per cent. The small amount of this acid did not permit of its identification. The Alcohols. ihe oil obtained by the above hydrolysis, when tested with semicarb- azide, was found still to contain a considerable amount of ketone, not¬ withstanding the previous exhaustive treatment with bisulphite. A preliminary distillation showed that the greater part passed over be¬ tween 190° and 250°; that boiling above 250°, which will be subse¬ quently referred to, possessed a beautiful indigo-blue colour. The oil was therefore fraction illy distilled until that passing over below 250° was quite free from any blue colour. In order to separate from this oil the last portion of ketones, recourse was had to the following method. 20-7 Grams of sodium were dissolved in 250 c.c. of absolute alcohol, and 100 grams of semicarbazide hydrochloride, made into a paste with alcohol, were introduced. An alcoholic solution of semicarbazide was thus obtained, sufficient in amount to combine with the 128 grams of oil employed, had the latter consisted entirely of methyl heptyl ketone. This mixture was boiled for half an hour, and then, while still hot, I: filtered from the sodium chloride. On concentrating the filtrate, a ¥' considerable amount of the crystalline semicarbazones separated, which$