A new synthesis of a-ethyltricarballylic acid / by H.A.D. Jowett.

  • Jowett, H. A. D. (Hooper Albert Dickinson)
Date:
[1901.]
Catalogue details

Licence: In copyright

Credit: A new synthesis of a-ethyltricarballylic acid / by H.A.D. Jowett. Source: Wellcome Collection.

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    any liquid distilled below 195°, the greater portion came over between 195° and 215°, leaving a small residue in the flask. On refractionation, the portion distilling at 205—208° under 17—21 mm. pressure was collected, the greater portion, boiling constantly at 208° under 21 mm. pressure, being put aside for analysis and for the determination of its density. The yield of refractionated product was 70 per cent, of the theoretical. On analysis : 0-1716 gave 0-3602 C02 and 0-1144 H20. 0 = 57-3; H = 7-4. 0T756 ,, 75 c.c. nitrogen at 24° and 764 mm. N = 4*7. Ci5H2s°6N requires C = 575 ; H = 73 ; 1ST = 4*5 per cent. The density at 16° compared with water at 16° was 1*0972. a-Ethyltricarballylic Acid, C02H-CH(C2H5)-CH(002H)-CH2*C02H. This acid was obtained from the ethyl cyanoethyltricarballylate in the following manner. The ester was first boiled with five times its weight of 40 per cent, aqueous sulphuric acid in a reflux apparatus until all the oily drops had disappeared, which generally required a period of 24—48 hours. The acid liquid was then saturated with ammonium sulphate and extracted with ether six times. The ethereal extract was distilled to a convenient bulk and extracted with dilute sodium carbonate solution. This was acidified with sulphuric acid, saturated with ammonium sulphate, and extracted with ether. The ethereal solution was washed with water, dried with calcium chloride, distilled to a low bulk, and then poured into ten times its volume of benzene. On standing, crystals separated which were filtered off; these, when dried, melted at 117° with effervescence. The acid was then heated in a small flask in a paraffin bath at 180° until all evolution of gas had ceased. After cooling, the mass was dissolved in a little hot water, boiled with animal charcoal, and filtered. On standing and stirring with a glass rod, the solution became pasty. The crystals were drained on a porous tile and recrystallised from a little water until of constant melting point; thus purified, they melted at 156-157° (corr.). The pure acid required about 20 times its weight of ether to dissolve it, but on evaporating this solution at the ordinary temperature, no crystals separated until all the ether had evaporated, when an oil was left which gradually became solid. On analysis: 0-1974 gave 0*341 C02 and 0*106 H20. 0 = 47*1 ; H = 6*0. 0-198 „ 0-342 C02 „ 0*1064 H20. C = 47*1 ; H = 6*0. C8H1206 requires C = 47-l ; H = 5*9 per cent. The anhydro-acid was prepared by adding the acid to three times its ; weight of acetyl chloride and boiling for 2 hours in a reflux apparatus. The acid slowly dissolved and the excess of acetyl chloride was removed