Several novel sulfonyl chloride functionalized ionic materials were used as media and catalysts for Beckmann rearrangement of cyclohexanone oxime and satisfactory results were achieved under mild conditions. The effects of all parameters were discussed. Moreover, the deactivation of ionic liquid catalytic system during the recycle was investigated by using FTIR spectroscopy and mass balance calculation. The trapping of acidic ionic material with basic product is proved to be mainly responsible for the difficulties encountered in the reuse of this type of material. A possible mechanism was conjectured.

★★★☆☆ Keywords: Beckmann rearrangement; Cyclohexanone oxime; Caprolactam; Sulfonyl chloride functionalized ionic materials; IR investigation

★★★☆☆ Z. Du et al. / Journal of Molecular Catalysis A: Chemical 237 (2005) 80–85.