Deactivation And Regeneration Of Fe-ZSM-5 Zeolite For One-Step Oxidation Of Benzene With N₂O To Phenol

The object of this paper was to investigate the deactivation rule and regenerated technology of Fe-ZSM-5 zeolite catalyst in the one-step oxidation of benzene to phenol with nitrous oxide.Based on the experimental investigation and some characterized methods such as TG-DTA,BET,TPO and C/H element analysis.Fe-ZSM-5 zeolite catalyst was prepared through liquid ion-exchanged method and hydrothermal pretreatment.The results of the performance evaluation of Fe-ZSM-5 zeolite showed that the initial activity of catalyst and the productivity of phenol were high,but they gradually decreased along with the run time.By the characterization means it could be found that the coke formed on the activity sites of catalyst was the main reason to lead catalyst deactivation,and two species of coke exited:high temperature carbon and low temperature carbon.The regenerating research indicated that the activity of deactivated Fe-ZSM-5 zeolite catalyst almost restored in nitrous oxide atmosphere and 723 K conditions.Based on the experiments in the isothermal integral reactor,the effect of tiny H₂O,NO,O₂ and NO₂ on the Fe-ZSM-5 zeolite catalyst were investigated by the method of single-factor.The results demonstrated that:(1)the addition of tiny H₂O almost had no influence on the activity of the zeolite catalyst.(2) the addition of tiny NO enhanced the activity of the zeolite catalyst.(3)the addition of tiny O₂ decreased the activity of the zeolite catalyst,and the activity dropped more obviously with the increase of O₂.(4)the addition of tiny NO₂ also decreased the activity of the zeolite catalyst.