Liquid-phase Beckmann rearrangement of cyclohexanone oxime into caprolactam

The research progress in liquid-phase Beckmann rearrangement of cyclohexanone oxime into caprolactam was reviewed. The novel liquid-phase Beckmann rearrangement processes were introduced emphatically under solid acid catalyst like molecular sieve, catalyst system containing alkylated reagents and DMF, ionic liquid catalyst, supercritical water or CO_2. It was pointed out that the green technological process using novel catalysts, particularly ionic liquid catalysts, would have wonderful prospects.