| 摘要 |
<p>A process for preparing and recovering lactams by the so-called Beckmann rearrangement of the corresponding ketoximes in a sulfuric acid medium is disclosed, wherein the mixture of lactam and sulfuric acid medium obtained from the Beckmann rearrangement is mixed with an aqueous solution of ammonium sulfate obtained as a by-product in the synthesis of hydroxylammonium sulfate in the preparation of said ketoximes. The lactam is then extracted from the resulting less acidic solution and the remaining acid solution, comprising an aqueous solution of ammonium hydrogen sulfate, is thermally decomposed to produce recoverable sulphur dioxide.</p> |
