Beta晶粒大小对乙醇转化制丙烯反应中Y-CeO_(2)/Beta催化剂催化性能的影响  

Effect of Beta Crystal Size on Catalytic Performance of Y-CeO_(2)/Beta Catalysts in the Conversion of Ethanol to Propylene

作　　者：靳欢 乐英红[1] 华伟明 高滋[1] JIN Huan;YUE Yinghong;HUA Weiming;GAO Zi(Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials,Department of Chemistry,Fudan University,Shanghai 200438,China)

机构地区：[1]复旦大学化学系上海市分子催化和功能材料重点实验室,上海200438

出　　处：《复旦学报（自然科学版）》2022年第6期716-724,F0002,F0003,I0009,共12页Journal of Fudan University：Natural Science

摘　　要：采用浸渍法合成了Beta晶粒尺寸分别为27 nm、53 nm和106 nm的Y-CeO_(2)/Beta负载型催化剂,通过XRD、低温N_(2)吸附、NH_(3)-TPD和CO_(2)-TPD表征手段对催化剂的物化性质进行表征。考察了Beta沸石晶粒大小对Y-CeO_(2)/Beta催化剂在乙醇转化制丙烯反应中催化性能的影响,丙烯得率随Beta晶粒尺寸增大而减小。Y-CeO_(2)与不同晶粒大小的Beta沸石复合后,都能显著促进异丙醇脱水生成丙烯,而且促进作用相当。随着Beta沸石晶粒尺寸增大,由于与沸石骨架部分结合的Al原子减少,即MPV反应活性位减少,导致Beta沸石的MPV反应活性下降,从而使得Beta沸石对丙酮经乙醇MPV还原转化为异丙醇的促进作用也逐渐下降,不利于丙酮中间体转化为丙烯,这就是Y-CeO_(2)/Beta催化剂的丙烯得率随Beta晶粒尺寸增大而减小的原因。The Y-CeO_(2)/Beta catalysts with Beta crystal sizes of 27 nm,53 nm and 106 nm,respectively were synthesized using an impregnation method.They were characterized by XRD,N_(2)adsorption,NH_(3)-TPD and CO_(2)-TPD.The effect of Beta zeolite crystal size on the catalytic performance of Y-CeO_(2)/Beta catalysts for the conversion of ethanol to propylene was investigated.The propylene yield decreases as Beta crystal size increases.The combination of Y-CeO_(2)with Beta zeolite of different crystal sizes significantly promotes the dehydration of isopropanol to propylene,and the promotion effect is comparable.With the increase of the crystal size of Beta zeolite,the MPV activity of Beta zeolite decreases due to the decrease of Al atoms partly bound to the zeolite framework,i.e.the decrease of active sites for the MPV reaction,which weakens the promoting effect of Beta zeolite component on the MPV reduction of acetone to isopropanol by ethanol and is not beneficial for the conversion of acetone intermediates to propylene.This is the reason why the propylene yield of the Y-CeO_(2)/Beta catalysts in the ETP reaction decreases with the increase of Beta crystal size.

关 键 词：乙醇转化 丙烯 钇-氧化铈/Beta沸石复合物 

分 类 号：O641.12[理学—物理化学]