Vapor-phase beckmann rearrangement over alumina-supported boria catalyst prepared by vapor decomposition method

Abstract

An alumina-supported boria (B 2O 3 content 25 wt%) prepared by vapor decomposition technique using ethyl borate in the presence of oxygen under atmospheric pressure exhibited high catalytic efficiency for the vapor-phase Beckmann rearrangement of cyclohexanone oxime: oxime conversion 100%, ε-caprolactam selectivity 95–98 mol% at 300 °C. The vapor decomposition B 2O 3/Al 2O 3 excelled the counterpart obtained by means of the conventional impregnation method in the selectivity to the lactam. The results of microscopic observation and surface area measurement suggested that the high lactam selectivity of the vapor decomposition catalyst was probably due to uniform dispersion of B2O3 onto Al2O3 which was effected by a procedure of vapor decomposition.