| 摘要 |
In an evaporation device (1), where a pressure of between 50 and 760 mm Hg and a temperature of 50 to 120 DEG C prevails, a residual acidic mixture arising from the manufacture of nitrated derivatives of phenols and a pretreated and recycled acidic mixture are processed. From the vapours emitted and from the nonevaporated liquors there is recovered, in a rectification device (4) and a crystallisation device (2) respectively, and purified and concentrated nitric acid, a carboxylic acid, picric acid and oxalic acid, all these products being in a marketable form. This process finds its application more particularly in making profitable the treatment of the effluents from plants for the production of nitrated derivatives of alkylphenols, especially of 4,6-dinitro-o-t-butylphenol, the carboxylic acid formed and recovered then being pivalic acid. <IMAGE> |
