Chemical examination of Ipomoea purpurea / by Frederick B. Power and Harold Rogerson.

  • Frederick Belding Power
Date:
[1908?]
Catalogue details

Licence: In copyright

Credit: Chemical examination of Ipomoea purpurea / by Frederick B. Power and Harold Rogerson. Source: Wellcome Collection.

    13/40 (page 11)
    no coloration with ferric chloride, but yielded precipitates with solu¬ tions of silver nitrate and lead acetate. It appeared to be identical with an acid which was subsequently obtained in larger amount by the fusion of the alcohol extract of the resin with potash, and which proved to be azelaic acid. The mother-liquor from this acid de¬ posited an exceedingly small amount of a crystalline substance which gave the above described coloration with ferric chloride, but it could not be obtained in a pure state. Treatment with Dilute Alcoholic Sulphuric Acid.—Thirty grammes of the resin were dissolved in alcohol, and such an amount of sul¬ phuric acid added, with a little water, that the total liquid contained about 5 per cent, of its weight of acid. The liquid was then heated in a reflux apparatus on the water-bath for about four hours, after which the alcohol was removed, and the residue subjected to distil¬ lation in a current of steam. The distillate, which contained a small amount of oil floating on the surface, was extracted with ether, the ethereal liquid being first washed with a little water, and then shaken with a solution of sodium carbonate in order to remove any acids present. After this treatment the ethereal liquid was dried with calcium chloride and the ether removed, when a small amount of a dark green oil was obtained. This was first distilled under a pressure of io mm., and then at the ordinary pressure, but as the range of temperature at which it passed over was very wide, it was evidently a complicated mixture. The amount of neutral oil thus obtained was 1*8 grammes. It was a pale yellow liquid, having a rather agreeable odor. The alkaline liquid obtained by extraction of the original oily product with sodium carbonate was acidified, and extracted with ether, the ethereal liquid being washed, dried with calcium chloride, and the solvent removed. A small amount of an oily acid was thus obtained, which was converted into an ammonium salt, and from this a silver salt was prepared. The latter was washed, dried in a vacuum over sulphuric acid, and analyzed. O 1288 of salt gave on ignition 0 0498 Ag. Ag = 38 7 C10H]9O2 Ag requires Ag = 38-7 per cent. The figures obtained by this analysis are seen to be in exact agreement with those required for the silver salt of a decylic acid, although it is probable that the acid was a mixture.