The deactivation and regeneration of HZSM-5 zeolite catalysts for synthesis of dichlorophenylphosphine in the gas phase

The reaction that synthesis of dichlorophenylp-hosphine over the catalyst HZSM-5 zeolite catalyst in the gas phase was studied as the target. The deactivation and regeneration characteristics of HZSM-5 catalyst were studied by N2 adsorption-desorption, scanning electron microscopy (SEM), X-Ray diffraction, FT-IR, TG-DTG tests. The results revealed that the structure of HZSM-5 zeolite scarcely damaged in the catalyst deactivation and regeneration process. It was found that both coke deposition and local dealumination of tetrahedral framework aluminum were the crucial factors in the deactivation of HZSM-5. Due to the coke forming on the catalyst surface and dealumination , the pore mouth of zeolite channels were blocked. The coke consisted mainly of aromatic compounds which from product depth oxidation. Regeneration of HZSM-5 catalyst had high activity and stability for the target reaction.