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

  • Frederick Belding Power
Date:
[1910]
Catalogue details

Licence: Attribution 4.0 International (CC BY 4.0)

Credit: Chemical examination of jalap / by Frederick B. Power and Harold Rogerson. 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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    maintain alkalinity. This treatment was continued until, on testing a small portion of the liquid with water, no turbidity was produced, a condition which was obtained in about 12 hours. The liquid was then allowed to cool, a little water added, and the alcohol removed, after which it was deprived of the excess of barium by means of carbon dioxide and filtering. The barium, which still remained in the filtrate in com- bination with the acids formed from the resin, was exactly precipitated with sulphuric acid, when, after removing the barium sulphate, a clear, dark red liquid was obtained. This liquid was subjected to distillation with steam in order to remove any volatile acids present. The distillate, which contained some oily drops floating on the surface, was made alkaline with sodium carbonate, concentrated, then acidified and extracted with ether, the ethereal liquid being washed, dried, and the solvent removed. A quantity (4 grams) of an oily product was thus obtained, which had the odor of valeric acid, and distilled between 174 and 176° as a colorless liquid. 0.1678 gave 0.36x4 C02 and 0.1524 H20. C = 58.7; H = 10.1. CsHl0Oz requires C = 58.8; H = 9.8 per cent. The density of the acid was 0.9480 at 16.5 °. It was optically active, and a determination of its specific rotatory power gave the following result: aD in a 25 mm. tube at 160 = + 40 10', whence [a]D +17.58°. It was thus evident that the above-described liquid consisted of the optically active valeric acid (d-methylethylacetic acid, CH(CH3)(C,H5). C02H), which is recorded1 as having [a]D +17.85°. The liquid from which the valeric acid had been removed by extraction with ether was distilled with steam, when the distillate was found to contain small amounts of formic and butyric acids. After the removal of the total volatile acids by distillation with steam, as above described, there remained in the distillation flask a clear liquid. This was extracted with ether, which, however, removed nothing. It was then concentrated under diminished pressure to the consistency of a sirup, when it still remained clear, and possessed a dark orange-yellow color. It had a strongly acid reaction, and did not reduce Fehling’s solution until after heating with a mineral acid. For the further examina- tion of this product, which may be termed the hydrolyzed resin, it was dissolved in alcohol, mixed with purified sawdust, and the thoroughly dried mixture extracted successively in a boxhlet apparatus with the same solvents as had been employed for the extraction of the original mixture of resins. The results were as follows: Petroleum (b. p. 40-60°) removed nothing.