Development of advanced zeolite catalysts for the vapor phase Beckmann rearrangement of cyclohexanone oxime

The vapor phase Beckmann rearrangement of cyclohexanone oxime to ε-caprolactam catalyzed by various zeolites was studied. The catalytic performance was greatly affected by both the zeolite structure and diluent solvent. When 1-hexanol was used in place of benzene, the catalytic performance of all catalysts except silicalite-1 was greatly improved. In particular, the selectivity and stability of H-LTL and H-OFF-ERI zeolites remarkably increased; both catalysts exhibited ca. 100% oxime conversion and ε-caprolactam selectivity of >95% for 6 h.