稀土改性HZSM-5催化乙醇脱水制乙烯  

Catalytic dehydration of ethanol to ethylene on HZSM-5 zeolites modified by rare earth

作　　者：成源海[1] 胡耀池[2] 李慧[2] 胡燚[2] 张红漫[1] 

机构地区：[1]南京工业大学理学院,江苏南京210009 [2]南京工业大学材料化学工程国家重点实验室,江苏南京210009

出　　处：《南京工业大学学报（自然科学版）》2009年第4期32-35,共4页Journal of Nanjing Tech University(Natural Science Edition)

基　　金：国家高技术研究发展计划(863计划)资助项目(2006AA020101);国家"十一五"科技支撑计划重点资助项目(2006BAE02B04)

摘　　要：采用浸渍法制备La、Ce、Sm、Eu等稀土(RE)金属改性的HZSM-5分子筛催化剂(RE/HZSM-5),考察它们在乙醇脱水制乙烯反应中的催化性能.通过X射线衍射(XRD)、N2吸附-脱附(BET)和氨程序升温脱附(NH3-TPD)等手段对其物化性能进行表征,并讨论反应温度对La/HZSM-5催化性能的影响.结果表明:少量稀土引入不破坏HZSM-5分子筛的骨架结构,只对表面酸性产生了较大的影响;表面酸量决定RE/HZSM-5催化乙醇脱水制乙烯的性能,酸量的增大有利于乙醇转化率的提高;在不同稀土改性的催化剂中,2%La/HZSM-5的催化性能最佳,在反应温度240℃、55%原料乙醇、进料质量空速(WHSV)2.5h-1的条件下,乙醇转化率和乙烯选择性分别达到99.3%和98.6%.Rare earth modified HZSM-5 catalysts （ RE/HZSM-5 ） were prepared by an impregnation method. Catalytic performances of RE/HZSM-5 for dehydration of ethanol to ethylene were investigated and different reaction temperatures were discussed on La/HZSM-5. And their physical and chemical properties were characterized by X-ray diffraction （XRD） , nitrogen adsorption-desorption （BET） and temperature programmed desorption of ammonia （ NH3-TPD）. Results showed that doping a small quantity of RE would not destroy the framework structure of HZSM-5 while the surface acidity was greatly changed. The activity for ethanol dehydration was dependent on acid sites on the catalyst surface, and the increasing of acid quantity would improve the conversion of ethanol. The best catalytic performance was obtained on La/HZSM-5. Under the optimized reaction conditions of 240 ℃, 55% ethanol concentration, and weight hourly space velocity （WHSV） 2.5 h^-1, the ethanol conversion and the ethylene selectivity of 2% La/ HZSM-5 were up to 99.3% and 98.6%.

关 键 词：HZSM-5 稀土 乙醇脱水 乙烯 

分 类 号：TQ221.21[化学工程—有机化工] O643.3[理学—物理化学]