The constituents of the essential oil from the fruit of Pittosporum undulatum / by Frederick B. Power and Frank Tutin.

  • Power, Frederick B. (Frederick Belding), 1853-1927
Date:
[1906]
Catalogue details

Licence: In copyright

Credit: The constituents of the essential oil from the fruit of Pittosporum undulatum / by Frederick B. Power and Frank Tutin. Source: Wellcome Collection.

    5/14 (page 1085)
    A determination of the amount of free acids and esters gave the following data : 20 grams of the oil required 0'2 c.c. of a semi-normal alcoholic solution of potassium hydroxide for the neutralisation of the free acids, and on subsequently adding an excess of alkali and boiling for thirty minutes, it was found that 4 c.c. of semi-normal alkali were required for the hydrolysis of the esters present. The entire oil was then shaken several times successively with small portions of 20 per cent, sulphuric acid, and afterwards washed well with water. The acid aqueous liquid was freed from adhering oil by shak¬ ing with ether, then made alkaline with potassium hydroxide, and again shaken with ether. After washing the ethereal liquid and drying it by means of potassium carbonate, the ether was removed, but only a trace of brown, resinous matter was obtained, thus indicating the absence of any basic substance such as methyl anthranilate. About 20 c.c. of the oil were shaken for four hours with a saturated solution of sodium bisulphite, but it yielded no solid compound, nor did the aqueous bisulphite liquid contain any aldehyde or ketone. As the amount of free acids contained in the oil was so very small, it was, after treatment with the dilute sulphuric acid, directly extracted several times successively with a 5 per cent, solution of potassium hydroxide, and subsequently washed with water. The alkaline aqueous liquid, after being freed from adhering oil, was acidified with sulphuric acid and extracted with ether, the ethereal solution being subsequently shaken with a solution of sodium carbonate to remove any acids, and finally washed with water. On removing the ether, a very small brown residue was obtained, which had an odour resembling that of eugenol and gave a brown colour with ferric chloride, but no definite benzoyl derivative could be prepared from it. The sodium carbonate liquid, which contained the acids from the pre¬ ceding extraction with potassium hydroxide, was acidified with sulphuric acid and extracted with ether. On removing the ether, a very small quantity of a brown oil was obtained, which had a strong odour of valeric acid and gave an intense violet coloration with ferric chloride. This violet coloration was apparently due to the presence of a trace of salicylic acid. The oily liquid, after standing some time, deposited crystals which, after several crystallisations from alcohol, melted at 62°, and evidently consisted of palmitic acid, since the melt¬ ing point was not changed on mixing the substance with an equal amount of pure palmitic acid. Prelmiinary Examination of the Terpenes. As a preliminary test for the presence of an oletinic or other unstable terpene, the oil, which had previously been treated with dilute sulphuric