Abstract: A multistep process for the liquid phase ammoximation of carbonyl compounds with H.sub.2 O.sub.2 and NH.sub.3, at 60.degree.-100.degree. C., at 1.5-5 bar and in the presence of a catalyst based on silicon, titanium and oxygen, characterized in that:a) in one or more primary steps, the H.sub.2 O.sub.2 : carbonyl compound molar ratio ranges from 0.9 to 1.15 by mols and the carbonyl component conversion is carried out up to at least 95%;b) in a last (exhaustion) step the H.sub.2 O.sub.2 : carbonyl compound ratio is in a higher range, i.e. from 1.5 to 3.0 by mols.

Abstract: The invention concerns a two-step process for the synthesis of caprolactam by reaction of cylcohexanone-oxime with an excess of oleum, carried out in a first step with only a portion of the oxime and in the presence of liquid SO.sub.2, according to usual "cold" techniques, the amount of free SO.sub.3 in the oleum being equal to or greater than 50% by weight, wherein said "cold" step is completed by a second "hot" step, by adding a second portion of oxime, the ratio between said second portion and said first portion ranging from 0.5 to 1.2.