Alkaline modification of ZSM-5 catalysts for methanol aromatization： The effect of the alkaline concentration  

作　　者：Zhenhao Wei Tengfei Xia Minghui Liu Qingsheng Cao Yarong Xu Kake Zhu Xuedong Zhu 

机构地区：[1]State Key Laboratory of Chemical Engineering, School of Chemical Engineering, East China University of Science and Technology, Shanghai 200237, China [2]Research Institute of Urumchi Petrochemical Company, PetroChina Company Limited, Urttmchi 830019, China

出　　处：《Frontiers of Chemical Science and Engineering》2015年第4期450-460,共11页化学科学与工程前沿（英文版）

摘　　要：The effects of alkaline treatment on the physical properties of ZSM-5 catalysts and on their activities for methanol to aromatics conversion have been investigated. A mild alkaline treatment （0.2 and 0.3 mol/L NaOH） created mesopores in the parent zeolite with no obvious effect on acidity. The presence of mesopores gives the catalyst a longer lifetime and higher selectivity for aromatics. Treatment with 0.4 mol/L NaOH decreased the number of Bronsted acid sites due to dealumination and desilication, which resulted in a lower deactivation rate. In addition, more mesopores were produced than with the mild alkaline treatment. As a result, the lifetime of the sample treated with 0.4 mol/L NaOH was almost five times that of the parent ZSM-5. Treatment with a higher alkaline concentration （0.5 mol/L） greatly reduced the number of Bronsted acid sites and the number ofmicropores resulting in incomplete methanol conversion. When the alkalinetreated catalysts were washed with acid, some of the porosity was restored and a slight increase in selectivity for aromatics was obtained.The effects of alkaline treatment on the physical properties of ZSM-5 catalysts and on their activities for methanol to aromatics conversion have been investigated. A mild alkaline treatment （0.2 and 0.3 mol/L NaOH） created mesopores in the parent zeolite with no obvious effect on acidity. The presence of mesopores gives the catalyst a longer lifetime and higher selectivity for aromatics. Treatment with 0.4 mol/L NaOH decreased the number of Bronsted acid sites due to dealumination and desilication, which resulted in a lower deactivation rate. In addition, more mesopores were produced than with the mild alkaline treatment. As a result, the lifetime of the sample treated with 0.4 mol/L NaOH was almost five times that of the parent ZSM-5. Treatment with a higher alkaline concentration （0.5 mol/L） greatly reduced the number of Bronsted acid sites and the number ofmicropores resulting in incomplete methanol conversion. When the alkalinetreated catalysts were washed with acid, some of the porosity was restored and a slight increase in selectivity for aromatics was obtained.

关 键 词：ZSM-5 alkaline treatment dealumination desilication MESOPORES METHANOL aromatics 

分 类 号：TQ241.21[化学工程—有机化工] TE624.99[石油与天然气工程—油气加工工程]