Process for producing ketoximes

Abstract

A process for the production of hydroxylamine, by the catalytic reduction of nitrogen monoxide with hydrogen in a mineral acid medium, followed by the reaction of the resulting mixture to produce saturated ketoximes, especially cyclohexanone oxime, by the oximation of the respective ketones with the hydroxylamine contained in the mixture, after adjustment of the pH-value with ammonia. The new process uses one of two reaction media: (a) ammonium hydrogen sulphate or phosphate; the solution, remaining after the oximation of the ketone and the separation of the ketoxime, is concentrated and evaporated to the dry state; the salt is thermally decomposed and transformed into acid ammonium salt, which is recycled as is the ammonia produced; or (b) pure mineral acid, alone or mixed with pure ammonium salt; the reaction mass, with the separated catalyst is passed over a strongly acid cationite; the released acid is recycled to hydroxylamine synthesis; the hydroxylamine is eluted from the cationite with a more impure mineral acid; or with an acid of medium strength (for instance, acetic acid; the resulting salt is used in oximation, without neutralization), or with various acids, with the production of the corresponding hydroxylammonium salts.

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