Research Progress of Beckmann Rearrangement of Cyclohexanone Oxime to Caprolactam

The Beckmann rearrangement of cyclohexanone oxime to caprolactam is an important industrial procedure . The reactions which proceed in gas solid phase; solid liquid phase; ionic liquid system and supercritical fluid without use of concentrated sulfuric acid as catalyst are introduced. The results show that, when reaction proceeds in gas solid phase, more by product is produced and the catalyst is easily inactivated with short service life. When in the solid liquid phase, reaction condition is mild and by product is less. While under ionic liquid system and supercritical fluid, the use of organic solvent can be omitted and by product is less.