Chemical examination of pumpkin seed / by Frederick B. Power and Arthur H. Salway.

  • Frederick Belding Power
Date:
[1910?]
Catalogue details

Licence: In copyright

Credit: Chemical examination of pumpkin seed / by Frederick B. Power and Arthur H. Salway. Source: Wellcome Collection.

    6/20 page 348
    Specific gravity 2o°/20° Acid value. Saponification value.... Iodine value. Expressed oil. O.9220 3-4 189.4 119.7 Oil extracted by petroleum. O.9212 3-5 189.0 119.6 For a complete chemical examination of the oil, 250 grams of it were employed. It was first subjected to distillation with steam. The dis¬ tillate contained no volatile oil and had only a very slight .acid reaction, which appeared to be due to traces of acetic acid. Hydrolysis of the Oil. The oil which had been subjected to distillation with steam, as above described, was separated from the water, the latter then extracted with ether to recover a small amount of suspended oil, and, after adding this to the main portion, the whole was hydrolyzed by heating with an alco¬ holic solution of 70 grams of potassium hydroxide. The greater portion of the alcohol was then removed, water added, and the alkaline liquid repeatedly extracted with ether. The ethereal liquids were united, washed with a little water, dried with anhydrous sodium sulphate, and the ether removed, when about 1 gram of a yellow solid was obtained. On fractionally crystallizing the latter from ethyl acetate, the least solu¬ ble fraction wras obtained in colorless needles, melting at 162-163 °. After drying at no° it was analyzed: 0.0698 gave 0.2139 C02 and 0.0749 H20. C = 83.6; H = 11.9. C27H460 requires C = 83.9; H = 11.9 per cent. The analysis of this substance, together with the characteristic color reactions yielded by it, establishes its identity as a phytosterol. The mother liquors from this phytosterol yielded crystalline deposits melting considerably lower than the latter, and the presence of another substance of this class, having an initial melting point of 140°, was indi¬ cated. On account of the very small amount of material it was, how¬ ever, not possible to isolate the more soluble compound in a state of purity. The Fatty Acids. The alkaline, aqueous solution of potassium salts, which had been ex¬ tracted wTith ether, as above described, was acidified with sulphuric acid and the liberated fatty acids taken up by ether. The ethereal solution was washed, dried, and the solvent removed, when 225 grams of total fatty acids were obtained. The constants of the mixed acids were de¬ termined in a portion from which the last traces of ether had been re¬ moved by heating for some time at ioo° under diminished pressure, and were then as follows: M. p. (complete fusion), 310; d 50°/50° = 0.8886; neutralization value, 199; iodine value, 123.5. Optically inac¬ tive. A determination of the acetyl value indicated the absence of hy-
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