The constituents of the essential oil of American pennyroyal / by Marmaduke Barrowcliff.

  • Barrowcliff, Marmaduke.
Date:
1907
Catalogue details

Licence: In copyright

Credit: The constituents of the essential oil of American pennyroyal / by Marmaduke Barrowcliff. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    01165 gave 0-3302 COg an I 0-1176 H^O. C = 77-3; H=ll-2. CjoH^gO requires C = ‘^'^-9 ; H = 11 -7 per cent. d 20°/20° = 0-9048; ao 4- 16°22' in a 1-dcm. tube. This fraction was examined after the composition of the following one had been determined, and was found to consist largely of the constituents of that fraction. Fraction 212—217°.—This was by far the largest fraction obtained and amounted to 620 grams : 0-1349 gave 0-3849 COg and 0-1358 Rfi. C = 77-8 ; H=ll-2. CioHigO requires C = 77-9 ; H = 11-7 per cent. CioHjgO ,, C = 78-9; H = 10-5 d 20°/20°= 0-9121; + 19°8' in a 1-dcm. tube. This fraction combined completely with hydroxylamine, yielding an oily oxime which deposited no solid, even on long standing. As there appeared to be still some pulegone present, 100 grams of the fraction were treated with sodium bisulphite solution in the manner previously described, when 8-5 grams of a bisulphite compound were obtained. This, when decomposed with a solution of potassium hydroxide, yielded an oil which, both by its boiling point and by its semicarbazone, was identified as pulegone. Isolation of \-Menthone and d-\soMenthone. Ten grams of the fraction (b. p. 212—217°) from which the further quantity of pulegone had been removed, were treated with semi- carbazide hydrochloride and sodium acetate. The semicarbazone thus obtained was dissolved in hot absolute alcohol, in which the greater portion appeared to be very sparingly soluble. On cooling, a quantity (8-5 grams) of a substance separated in long, handsome needles which melted at 184—186°, and this melting point was not altered by further crystallisation. This substance corresponded in melting point with ^menthone semicarbazone, and a mixture of it with the semicarbazone from pure ^-menthone (Kahlbaum) showed no diminution in melting point. The ketone was regenerated from it by distilling rapidly in steam with dilute sulphuric acid. The distillate was then extracted with ether, the ethereal solution dried with anhydrous sodium sulphate, and the solvent removed, when a liquid was obtained which distilled completely at 207—208° : 0-1320 gave 0-3768 COg and 0-1370 H2O. 0 = 77-8; H = ll-5. CjqHisO requires 0 = 77-9; H=ll-7 per cent. d = 0-8957 at 20°/20°; - 10°8' in a 1-dcm. tube, whence [a]D - 11-3°. This substance y^as evidently ?-menthone, and the difforepcq between