Investigation of macro-/mesoporous Re2O7/Al2O3 catalysts prepared by a particle-template method for butylene metathesis

Macro-/mesoporous Al2O3 supports were prepared by using monodisperse polystyrene (PS) microspheres as a template. The pore volume and BET surface area of the Al2O3 supports increased considerably with increasing amounts of the PS microspheres; further investigation showed that PS template only increased the volume of macro-pores but did not change the volume of meso-pores or micro-pores. Macro-/mesoporous Re2O7/Al2O3 metathesis catalysts were prepared through loading Re2O7 onto the as-prepared macro-/mesoporous Al2O3 supports, and their catalytic performance was tested in a fixed-bed tubular reactor using the metathesis of normal butylenes as a probe reaction. The results showed that the prepared macro-/mesoporous Re2O7/Al2O3 catalyst had high activity with consistent selectivity; propylene and pentene accounted for more than 90 wt% of the metathesis products, while the amount of ethylene plus hexane was less than 10 wt%, the majority of which was hexane. These Re2O7/Al2O3 catalysts had not only higher activity, but also longer working life span and higher tolerance to carbon residues than conventional Re2O7/Al2O3 catalysts.