The chemistry of the bark of Robina pseud-acacia, Linné (false acacia or common locust) / by Frederick B. Power.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
[1901]
Catalogue details

Licence: In copyright

Credit: The chemistry of the bark of Robina pseud-acacia, Linné (false acacia or common locust) / by Frederick B. Power. Source: Wellcome Collection.

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    addition of water. This crude product was treated first with petroleum spirit, which extracted a quantity of very dark coloured, soft resin and fatty matter. The portion umbssolved by the petroleum spirit was dissolved in warm alcohol, and the concentrated solution poured into a large volume of water acidulated with sulphuric acid, when the resin separated in a flocculent form, and, after being washed and dried, could be reduced to a fine, brown pow7der. The yield of soft resin was 86 grammes, or 1*23 per cent, of the weight of the bark; the yield of dry, powdered resin was 37 grammes, or 0'53 per cent, of the weight of the bark. After distilling off the alcohol from that portion of the above crude resin that had been dissolved in it, it was observed that the liquid in the flask became quite gelatinous when cold. Before it was poured into water, therefore, it was again ex¬ tracted with petroleum spirit (b.p. 40-60° C.) by shaking in a separator. The latter liquid left on evaporation a soft, fatty matter, which was found to be completely soluble in hot alcohol. On treating this solution with a little animal charcoal, and filtering while hot, there separated on cooling a mass of nearly white substance, which, however, when spread on glass and allowed to dry in a vacuous desiccator, became of a dark slate-blue colour. It was completely soluble in chloroform, and the filtered solution left a residue which, after drying in vacuo over sulphuric acid and solid paraffin, had a melting point of about 75° C. On analysis it gave the following figures : — 0‘1458 gramme of substance gave 0-3816 gramme of C02 = 71*4 per cent. C and 0T466 gramme H20 = 1T2 per cent. H. This result was sufficient to prove that the substance in question is not a paraffin nor an alcohol similar, for example, to cholesterol. It was probably a mixture of bodies, and had the general properties of a wax. The dry resin obtained by precipitation with acidulated water is soluble in glacial acetic acid and also in solutions of the alkali hydrates, from which it is again precipitated on the addition of water. When heated with acetic anhydride no crystallisable acetyl derivative could be obtained. 10 grammes of the resin were brought into 50 grammes of solid potassium hydroxide in a state of fusion, and the mixture kept at that temperature for a few minutes. The very dark coloured mass had a phenolic odour, and, when taken up with water and an excess of sulphuric acid added, a black resin was separated, while at the same time an almost intolerable odour was developed, reminding of that of skatol, and which was