Synthesis Of Fe-ZSM-5 And Its Catalytic Performance Of N₂O One Step Oxidation Benzene To Phenol

N₂0 one pot oxidation benzene to phenol is a new process to synthesis phenol.Because of the moderate amount of acid,better surface area and suitable hydrothermal stability,Fe-ZSM-5 has been labeled as one of the best catalyst for this reaction.However,the deactivation of Fe-ZSM-5 has been the major obstruction for its industrialization.In recent years,researchers found the introducing of mesoporous could solve this problem effectively,which makes Fe-ZSM-5 became focus.In this paper,ZSM-5 was synthesized in one-step method.Conditions such as Si/Al ratio,crystallization temperature,crystallization time and Si/TPAOH ratio are investigated systematically.After the Fe modification,Fe-ZSM-5 was applied to the reaction of benzene to phenol.The experiment results show that low Si/Al ratio has better catalytic performance,the yield of phenol beyond 80%,the life of catalyst almost 10 h.All these results may ascribe to the better acid,more Fe species in the term of isolated tetrahedral Fe+ and meso-strcture.Compared the difference of catalytic performance in different synthesis methods:ion-exchanged method and hydro-thermal method,the results showed that Fe-ZSM-5 synthesized by ion-exchanged method has better catalytic performance in high Fe load?1%wt?,while Fe-ZSM-5 synthesized by hydro-thermal method has better catalytic performance in low Fe load?0.25%wt?,which was attributed to the influence of Fe species.The introducing of NaOH and CTAB had strong influence on Fe-ZSM-5 in morphology and crystal size.The results show that the introducing of NaOH can transform the Fe-ZSM-5's morphology from sphere to hexagonal prisms.However,the meso-structure,acid sites may decrease.And the isolatedtetrahedral Fe3+ decreases.On average,these results improve the catalytic performance,the yield of phenol nearly 82%,which 2 percentage higher then Fe-ZSM-5 without introducing the NaOH.But the disappearance of mesoporous weakens the catalytic life.The introducing of CTAB improves the crystal size of Fe-ZSM-5?from 400-500 nm to 2 ?m?.A few of CTAB can improve the acid sites,crystallization and the initial catalytic activity.But the excessive of CTAB may cause the flocculent mixed crystal and the disappearance of meso-structure,which may weakens the catalytic performance and accelerates the rate of inactivity.