The action of antimony trichloride upon diazotised diamines / by W.H. Gray.

  • Gray, William Herbert.
Date:
[1926.]
Catalogue details

Licence: Public Domain Mark

Credit: The action of antimony trichloride upon diazotised diamines / by W.H. Gray. Source: Wellcome Collection.

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    filtered solution of antimony trioxide (3 g.) in 40% hydrochloric acid (7-4 c.c.). The antimony compound separated in yellow plate¬ lets, m. p. 94° (corr.) with slight explosion. When treated with water, this gave an amorphous, white precipitate, the suspension giving an immediate deep red colour with F-salt and darkening with frothing on the addition of alkali. Unlike the p-acetyl com¬ pound, it cannot be crystallised from dilute hydrochloric acid, being at once decomposed on heating, nor dried at 60°, which changes it to a tar. On heating the aqueous suspension, aniline was detected in the steam. For analysis, it was dried on a tile in a desiccator for 2 hours (Found : Sb, 19-5. C16H1602N6Cl5Sb requires Sb, 19-5%). After several days in the dark at room temperature, it decomposes to a dark, frothing tar. m-Acetylaminobenzenediazonium Chromate.—The foregoing com¬ pound (1*25 g.) was ground with several small portions of ice-cold water, and the clarified extract precipitated with cold aqueous chromic acid. Clusters of yellow plates (0-5 g.) separated. After drying in the desiccator, these exploded violently when pressed by a spatula, or even on the addition of cold ammonia solution. In a comparative test, a small quantity of this compound detonated when heated on a spatula and the corresponding p-compound (see above) burned rapidly but quietly (Found : Cr, 19-5. C8H905N3Cr requires Or, 18-6%). Analytical.—The estimation of antimony in organic compounds by oxidation with permanganate followed by iodometric titration (Fargher and Gray, J. Pharm. Expt. Ther., 1921, 18, 356; compare Gray, J., 1923, 123, 641) has now been improved and shortened by the use of oxalic acid to remove the manganese oxides and urea to remove nitrous acid. 0-2 G. of the substance, mixed with powdered potassium permanganate (3 g.), is treated with 50% sulphuric acid (15 c.c.) and then gradually with concentrated sulphuric acid (15 c.c.). The mixture is diluted with water (15 c.c.), boiled gently for 5 minutes, and decolorised with saturated oxalic acid solution. It is then diluted to 120 c.c., urea (1 g.) and potassium iodide (2-5 g.) are added, and the liberated iodine is determined by thiosulphate after 15 minutes’ standing. Towards the end, the liquid should again be diluted considerably with water; the yellow colour, not due to iodine, which otherwise persists past the end-point, is thus destroyed. Chlorine. After a number of methods had been tried for the deter¬ mination of chlorine in presence of antimony in these compounds, the following was found to be the only practicable one. The substance <0-2 g.) is mixed with a little water and potassium permanganate (1 g.) in a small flask containing a tube of concentrated sulphuric acid. The