The constitution of chaulmoogric and hydnocarpic acids / by Marmaduke Barrowcliff and Frederick B. Power.

  • Barrowcliff, Marmaduke.
Date:
[1907]
Catalogue details

Licence: In copyright

Credit: The constitution of chaulmoogric and hydnocarpic acids / by Marmaduke Barrowcliff and Frederick B. Power. Source: Wellcome Collection.

    14/26 (page 568)
    Oxidation of Chaulmoogric Acid in Alkaline Solution with an Excess of Potassium Permanganate.—One hundred grams of chaulmoogric acid were dissolved in an aqueous solution of 50 grams of potassium hydroxide, and the opalescent liquid diluted with water to the measure of 5 litres. This was allowed to flow slowly, with constant stirring, into 11 litres of a 3 per cent, solution of potassium permanganate, the temperature being kept below 20° by the addition of ice. After standing for some hours, the excess of permanganate was removed by sodium bisulphite. The liquid was then heated, filtered, the filtrate concentrated, acidified with sulphuric acid, and distilled with steam. The distillate contained an acid which was converted into its barium salt, and from this a silver salt was prepared and analysed : 0-3024 gave 0-1960 Ag. Ag = 64-8. C2H302Ag requires Ag = 64-7 per cent. The volatile product was thus identified as acetic acid. From the results of an experiment subsequently described, this appears to have been produced by the decomposition of malonic acid, and not to have been a direct product of oxidation. The non-volatile acids were then extracted and converted into their methyl esters. On distilling the product under 15 mm. pressure the following fractions were obtained : below 220° (45 grams); 220—260° (8 grams); 260—270° (55 grams) ; 270—280°/15 mm. (5 grams). These fractions were all optically inactive, and were subsequently examined as follows. Isolation of n-Undecane and n-Dodecane Dicarboxylic Acids. Fraction boiling below 220°/15 mm.—This was fractionally distilled under 15 mm. pressure, when it was further resolved into the following fractions: (a) below 200° (5 grams); (6) 200—205 (13 grams); (c) 205—210° (3 grams); (d) 210—215°/15 mm. (13 grams). Fraction (c) and (d), on standing, deposited a crystalline substance, which was collected and crystallised from methyl alcohol. It then separated in clusters of needles melting at 41°: 0-1335 gave 0-3272 C02 and 0-1256 H20. C = 66-8; H = 10-5. 0-1279 „ 0-3132 C02 „ 0-1204 H20. C = 66-8 ; H = 10'5. C16H30O4 requires C = 67T ; H= 10-5 per cent. 0 6876 required for hydrolysis 9*5 c.c. A/2 NaOH, the calculated amount for C12H24(C02Me)2 being 96 c.c. By the hydrolysis of this ester an acid somewhat sparingly soluble in ether was obtained. It was crystallised from ethyl acetate, from which it separated in small, glistening leaflets melting sharply at 124° :