Abstract
Publisher Summary This chapter describes catalyst deactivation of high silica metallosilicates in Beckmann rearrangement of cyclohexanone oxime. The vapor phase Beckmann rearrangemem was carried out over high silica ZSM-5 type metallosilicates to elucidate the effect of acid strength on caprolactam (CL) selectivity and catalyst deactivation rate. It was found that the indiosilicate, which had the lowest acid strength, was the best catalyst among the metallosilicates. When carbon dioxide and methanol were used as diluent gas and diluent solvent of cyclohexanone oxime, respectively, the deactivation rate decreased over indiosilicate. Furthermore, when the indiosilicate was modified with a precious metal, the catalyst deactivation significantly decreased. It was considered that the oxidation of coke on the surface was accelerated by the precious metal. In this chapter, the rearrangement has been carried out over a ZSM-5 type metallosilicates including iron, gallium or radium in the crystal lattice to elucidate the effect of acid strength on the catalyst deactivation rate. The chapter also examines the effects of diluent solvent and diluent gas of CHO on the deactivation rate and CL selectivity. Furthermore, the rearrangement was carried out over an indiosilicate modified with precious metals to decrease the catalyst deactivation.
Published Version
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