Y型分子筛中对称与不对称Co(II)Salen型席夫碱配合物的结构和催化性能

用自由配体法将对称、不对称Co(II)Salen型席夫碱配合物封装于Y型沸石分子筛的超笼中, 并采用FTIR、UV- Vis、热分析和催化技术研究了其空间结构和催化性能. 结果表明, 被封装于分子筛超笼中的Salen型席夫碱配合物, 同样具有未封装配合物的物理化学性能, 也没有影响分子筛的框架结构；在以O2作氧化剂, 催化苯乙烯环氧化反应中表现了非常高的反应活性和稳定性；金属配合物的量子化学密度泛函计算结果揭示了配合物的催化性能与轨道能量密切相关.

Epoxidation of Styrene Catalyzed by Zeolite-encapsulated Symmetrical and Unsymmetrical Co(Ⅱ)Salen-type Schiff Base Complexes

Zeolite Y encapsulated symmetrical and unsymmetrical Co(II)Salen- type Schiff base complexes with different substituents were prepared by flexible ligand method and characterized by XRD, FTIR, UV- Vis, and thermal analysis. The effects of substituents on encapsulation and catalytic activity of the encapsulated complexes were also investigated. The results indicated that the complexes could be formed and encapsulated in the supercages without affecting the zeolite framework structure. The prepared castalysts exhibited high activity, selectivity, as well as stability in the epoxidation of styrene with molecular oxygen. The highest conversion and selectivity towards styrene oxide could reach 93.2% and 75.6% respectively at 110 ℃ under 0.1 g catalyst, 5 mmol of styrene and oxygen saturated conditions. The recycled catalyst did not show any decrease in catalytic activity and selectivity. Substitution of the aromatic hydrogen atom of the Salen ligand with electron withdrawing group Br decreased the amount of the complex encapsulated in the zeolite cavities, but could improve the catalytic activity of the encapsulated complex. Density functional theory calculation results indicated that the catalytic activities depended on orbital energy of metal complexes.