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.

    9/38 (page 85)
    Optical Rotation of the Crude Resin. It has been indicated by P. Guigues1 that the specific optical rotatory power of certain convolvulaceous resins is a factor which may be utilized for discriminating between them, and for the detection of substitutes and adulterants. This factor was therefore determined for the resin employed in the present investigation with the following result. A quantity of the crude resin was dissolved in 50 cc. of alcohol, and the solution boiled with successive, small portions of animal charcoal until it became practically colorless. The rotation of this liquid in a 1 dcm. tube was trD —20 o', and the amount of substance contained in 10 cc. of the liquid, after drying at 105-110°, was 0.5400, hence [a]D—37.0°. This result is in fairly close agreement with the figures recorded by Guigues and by Cowie2 for a decolorized jalap resin, which are [a]D —36.0 and —37-3° respectively. Preliminary Extraction of the Crude Resin with Different Solvents. In order to ascertain the general character of the crude resin, a weighed amount (about 5 grams) was dissolved in alcohol, mixed with purified sawdust, and the thoroughly dried mixture extracted successively in a Soxhlet apparatus with various solvents. The percentages of extract, dried at no°, were as follows: I. Petroleum (b. p. 40-60°) extracted 1.9 II. Ether “ 9.7 III. Chloroform “ 24.1 IV. Ethyl acetate “ 22.0 V. Alcohol “ 38.8 Loss, 3.5 100.0 For the purpose of a complete examination of the constituents of the resin, a large quantity of the crude material was employed. This was dissolved in alcohol, mixed with purified sawdust, and the thoroughly dried mixture extracted first with ethyl acetate, and subsequently with alcohol. The alcohol extract was then again extracted with ethyl acetate in a similar manner, after which the undissolved material was removed by means of alcohol, this portion being designated as the “alcohol ex- tract of the resin.” The entire amount of material removed by ethyl acetate was then mixed with a large quantity of purified sawdust, and the mixture thoroughly dried, after which it was submitted to prolonged successive extractions with petroleum (b. p. 40-60°), ether, chloroform, 1 J. pharm. chim. [6], 22, 241, and Chem. Zenir., 1907, I, p. 309; Bull. soc. chim. t4]. 3, 872 (1908). Compare also Power and Rogerson, Am. J. Pharm., 80, 251 (I9o8), and Cowie, Pharm. J., 82, 89 (1909). 2 Loc. cit.