Cr沸石在环己烷氧化反应中的催化性能

Performance of Cr Zeolite Catalyst in Cyclohexane Oxidation

以环己烷氧化反应为探针,系统地比较了采用离子交换法、“ship-in-bottle”法和水热法制备的C r沸石的催化性能和稳定性。通过X射线衍射、氮吸附、傅里叶变换红外光谱、漫反射紫外-可见光谱和差热分析方法对催化剂进行了表征。分析结果表明,不同方法制备的C r沸石催化剂的性质和状态不同。实验结果表明,水热法制备的C rY催化剂的催化活性最高,但C r的浸出最严重。选择不同Schiff碱配体N,N′-双(水杨醛)-丙二胺(L1)和N,N′-双(水杨醛)-环己二胺(L2)、采用“ship-in-bottle”法制备的C rL1/Y和C rL2/Y催化剂的性能均优于离子交换法制备的C r/Y催化剂,其中C rL2/Y催化剂的性能尤为突出,配体对催化剂的性能也有一定影响。

Cr zeolite catalysts were prepared by ionexchange method, “ ship -in -bottle” method and hydrothermal method. Reactivity and stability of catalysts in cyclohexane oxidation were investigated in detail. Catalysts were characterized by means of XRD, N2 absorption, PTIR, UV - Vis and DTA. Cr zeolite catalysts prepared by different methods were different in states and properties. Catalytic activity of CrY catalyst prepared by hydrothermal method was the highest among the prepared Cr zeolite catalysts, but leaching of Cr was very serious. Reactivity of CrL1/Y （ L1 ： N, N＇ - bis （salicylidene） - 1,3 - propanediamine） and CrL2/Y （ L2 ： N, N＇ - bis （salicylidene） -1,2- cyclohexanediamine）catalysts with different Schiff- base ligands prepared by“ ship -in- bottle” method were better than that of Cr/Y catalyst prepared by ion - exchange method. CrL2/Y catalyst possessed most outstanding catalytic activity. Ligand had some positive effect on reactivity and stability of catalyst.