配体对固载型锰希夫碱催化剂的影响

Effect of ligands on the supported Mn schiff base complexes

以官能团化的MCM-41为载体,通过配位键键连法制备了6种不同配体的固载型锰希夫碱配合物,并使用FT-IR、XPS、N2吸附-脱附、DR-UV/vis、XRD和TGA-DTA等技术对其进行表征。将制得的催化剂用于环己烯的氧化反应,考察了催化剂催化分子氧氧化环己烯的反应性能,结果表明配体的类型对催化剂的活性和产物的选择性有较大的影响,配体的供电性大或共轭体系大都可以增加催化剂的活性,吸电子基的引入使固载型催化剂的固载量增加。此外,该固载型催化剂可以重复使用多次,但活性有一定程度的下降。

Supported Mn schiff base catalysts were prepared by coordinate bonds between the metal manganese and amino MCM-41,and characterized by various physico-chemical measurements such as FT-IR、XPS、N2 adsorption-desorption、DR-UV/vis、XRD and TGA-DTA.The catalytic property for oxidation of cyclohexene using dioxygen as oxidant had been investigated.The results indicated that types of ligands played great influence on the activity of the catalysts and the selectivity of products,the ligands with strongly electron-donating groups and the great conjugate π bond system enhanced the activity of the catalysts,and the electron-withdrawing groups increased the supporting amount of the neat catalysts.Moreover,the activity of the supported catalyst was reduced to some extent after being reused four times.