[Mo_2O_4]^(2+)交联层柱粘土的制备及其结构和性能的研究

THE STUDIES ON THE PREPARATION, STRUCTUREAND PROPERTIES OF [Mo_2O_4 ]^(2+) CROSS-LINKED PILLARED CLAY

以[Mo_2O_4]^(2+)溶液为交联剂制备了钼交联层柱粘土。并用XRD、IR、LRS、XPS及TPD等手段对其结构及Mo的存在状态进行了研究。结果表明:[Mo_2O_4]^(2+)被交换进入了层间,所得层柱粘土的d_(?)～13A,其柱结构为Mo_xO_y的簇状氧化物。当交联剂在粘土层间的量超过粘土的交换容量时,Mo在层外表面偏析。酸性研究显示:Mo的加入使钼交联层柱粘土的酸中心数较之原土增加,并以Lewis酸为主。用异丙醇脱水和氧化反应考察钼交联层柱粘土的催化活性,结果表明,这种层柱粘土不仅具有酸催化活性,同时由于钼的引入而具有氧化活性和抗积炭性能。

Mo Cross-linked pillared Clay (Mo-PC) has been prepared with [Mo2O4 ] 2+ aquated solution as cross linking agent. The structure and properties of the prepared Mo-PC were studied by XRD, IR, LRS, XPS and TPD methods. The results show that Mo can be exchanged into interlayer, the Mo-PC has the basal spacing d001～13 A and the pillar structure is MoxOy clusters which are so symmerical that Mo-PC has no activity in LRS. It is found that MoxOy become pillars when Mo wt.% ≤ 3.96 and will be segregated out of interlayer onto the surface when Mo wt.% > 3.96. The acidity of Mo-PC were studied by IR and NH3-TPD. Mo-PC has more acid sites than Ca-montmorillonite due to having Mo. The acid sites are mainly Lewis type. The dehydrogenation and dehydration of isopropanol were chosen as a probe to test the catalytic properties of the catalysts prepared. The results indicate that Mo PC has higher dehydration activity than Ca-montmorillonite and also has dehydrogenation activity for having Mo. No coking reaction was detected on the Mo-PC.