| 摘要 |
Trinitrotoluene, completely or nearly free from mineral acids, is purified by treating it in the molten state at or about its solidifaction point and preferably not above 83 DEG C., with a dilute aqueous solution of an alkali sulphite such as sodium sulphite in the presence of a weakly acidic substance or mixture of substances in quantity at least sufficient to maintain an appreciably steady hydrogen ion concentration throughout the treatment, the initial hydrogen ion concentration of the aqueous solution lying between pH 7,0 and 8,3. Suitable weakly acidic solutions are a mixture of sodium acetate and acetic acid, sodium mono hydrogen phosphate and sodium dihydrogen phosphate, boric acid alone or where the crude trinitrotoluene contains a little residual acid boric acid mixed with sodium borate, ammonium bicarbonate or sodium bicarbonate. In an example molten crude trinitrotoluene, previously washed with water until practically free from mineral acid, is stirred with an aqueous solution of sodium sulphite, sodium monohydrogen phosphate and sodium dihydrogen phosphate. The mixture is allowed to settle and the separated trinitrotoluene is treated with a further amount of the aqueous solution, separated and washed. The process may be carried out continuously.
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