![Thumbnail: [Volume 34, 1901 page 496]](/journals/rsnz/images/rsnz_34/thumbnails/rsnz_34_00_0527_0496_ac_02.gif)
Karakin.
Since this compound is the only substance in the fresh nut of any considerable interest, the method of preparation and properties of it shall alone be given in detail. The fresh kernels are first put through a sausage-machine, and then through the wooden rollers of a wringing-machine, and the mash well stirred with one and a half times its weight of methylated spirit and allowed to stand for thirty-six hours with repeated stirrings. The spirit is removed by a filter-press and the press-cake again extracted with alcohol. The united filtrates are distilled in a partial vacuum, at a temperature not exceeding 35†, until the greater part of the alcohol is removed. The turbid liquid gradually deposits crystals of karakin, together with a gummy bitter substance which can be removed by recrystallization from boiling alcohol. The purekarakin melts at 122†, dissolves easily in acetone, methyl alcohol, glacial acetic acid, acetic ether, and phenol; with, difficulty in cold ethyl alcohol (0.4 gram in 100 cc.) and water. It is very sparingly soluble in ether and benzene. Deposited from hot concentrated solutions in water or alcohol, it separates as an oil, which subsequently becomes crystalline. The compound reduces Fehling's solution readily. After hydrolysis with dilute hydrochloric acid it gives a yellow precipitate when warmed with sodium-acetate and phenyl-hydrazine solution (glucoside reaction). It is highly nitrogenous-Analysis agrees with the formula (C5H8NO5)8.
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| Calculated. | Found. | ||
|---|---|---|---|
| C | = | 37.0 | 37.2 |
| H | = | 4.9 | 4.8 |
| N | = | 8.6 | 8.6 |
| O (by difference) | = | 49.5 | 49.4 |
| 100.0 | 100.0 |
![Thumbnail: [Volume 34, 1901 page 497]](/journals/rsnz/images/rsnz_34/thumbnails/rsnz_34_00_0528_0497_ac_02.gif)
Molecular weight in phenol solution: Calculated (C5H8NO5)8 = 486; found = 450.
The characters given by Skey for the karakin prepared by the animal-charcoal method differ in two important respects from those above described. The melting-point according to Skey is 100†, and the substance contains no nitrogen. At first sight it would therefore seem that the two substances are not identical. From Skey's paper, however, it would appear that the karakin was not recrystallized, and this would account for the difference in the melting-points. The failure, on the other hand, to detect nitrogen in organic substances has occurred so often in the history of chemical research, more particularly before the application of the metallic-sodium test had become general, that the authors do not attach much importance to this apparent discrepancy. They would add that they have prepared karakin by Skey's method and found it to contain nitrogen, and to have the same melting-point as the compound already described.
The expenses in connection with this investigation have been defrayed by a grant from the Royal Society of London.