形貌、晶粒大小不同的ZSM-5分子筛的表征及催化性能的研究  

Characteristics and Catalytic Performance of ZSM-5 Zeoliteswith Different Crystal Size and Morphology

作　　者：王锋[1] 贾鑫龙[1] 胡津仙[1] 任杰[1] 李永旺[1] 孙予罕[1] 

机构地区：[1]中国科学院山西煤炭化学研究所煤转化国家重点实验室,山西太原030001

出　　处：《分子催化》2003年第2期140-145,共6页Journal of Molecular Catalysis(China)

摘　　要：对3种不同形貌、晶粒大小的ZSM-5分子筛催化剂进行了表征和催化性能的研究.用XRD、SEM和NH3-TPD等方法对ZSM-5分子筛进行表征,结果表明小晶粒分子筛的结晶度优于大晶粒分子筛,其酸性随着晶粒的减小而增强.对于MTG反应,ZSM-5分子筛酸性、晶粒大小和晶体形貌等因素对其催化活性产生显著影响.小晶粒的ZSM-5分子筛更有利于C5+和C9+的生成,而大晶粒的ZSM-5分子筛对对二甲苯的选择性高.TG结果表明ZSM-5分子筛上积炭覆盖酸性中心是导致催化失活的主要因素.Correlation between the crystal size, morphology and catalytic properties of ZSM\|5 zeolites were studied. The zeolites were characterized by XRD and SEM. The acidity was measured by temperature\|programmed desorption (TPD) of ammonia. Coking was studied by thermogravimetric analysis(TGA). It was found that the amount of acidity and crystallinity decreased with increasing of particle size of ZSM\|5 zeolites. Methanol conversion to hydrocarbons(MTG)was carried out over the three zeolites to evaluate the relation\|ship correlation between the physicochemical characteristics and catalytic performance of ZSM\|5 zeolites. In contrast to large crystallites, the aggregated H\|ZSM\|5 consisting of small crystallites showed high selectivities for C\-5\++ and aromatics. However, the aggregated H\|ZSM\|5 consisting of large crystallites showed high selectivities for p\|xylene. The results from TGA test obviously show that the coking tendency depends on the strength of sronger acid sites of the ZSM\|5 zeolites.

关 键 词：ZSM-5 分子筛 晶粒大小 酸性 积炭 形貌 表征 催化性能 

分 类 号：O643.36[理学—物理化学]