ZnCl_2/Si-MCM-41催化剂的制备、表征及催化性能研究

Synthesis, characterization and catalytic performance of ZnCl_2/Si-MCM-41catalysts

通过浸渍法制备了新型的环境友好催化剂ZnCl2/Si-MCM-41。考察了它在苯与苄氯的苄基化反应上的活性,探索了制备ZnCl2/Si-MCM-41负载试剂的最佳制备条件。研究表明:ZnCl2/Si-MCM-41的最佳制备条件是负载量为4mmol/g,活化温度为150℃,活化时间为5h。通过XRD、TG、FT-IR对催化剂进行表征,发现ZnCl2在较低负载量时,ZnCl2充分分散在载体孔道内,对催化剂载体的结构没有明显的影响,而且此负载试剂上苯的苄基化反应的活性中心不是晶体ZnCl2,而是存在于载体表面的非晶态ZnCl2物种。

In this paper, a new type of environmentally\|benign catalyst ZnCl\-2/Si\|MCM\|41 is prepared by the impregnating evaporation method. The catalytic activity of benezene benzylation over ZnCl\-2/Si\|MCM\|41 has been investigated. Research shows supported reagents have the highest activity with 4 mmol/g loading of ZnCl\-2, 150 ℃ calcined temperature and 5 h activity and the active sites of catalysts are not crystalline ZnCl\-2 but isolated ZnCl\-2. At optimal loading, most of the ZnCl\-2 should be present in the form of those isolated moieties, covering the internal channel surface of the MCM\|41. If the loading is increased further, ZnCl\-2 aggregates and forms a crystalline, the bulk\|like phase ZnCl\-2 tends to deposit at the pore mouths when the solvent is removed during the drying stage.