Synthesis of NaLTA zeolite confined CuO catalysts and superior catalytic properties for alkene epoxidation with H2O2 as oxidant

Abstract

The NaLTA zeolite confined CuO catalyst CuO@NaLTA was prepared via the method of ligand protected in situ with Cu2+-glycine complex as Cu source, and characterized by multiple characteristic techniques. The results revealed that CuO nanoparticles were highly dispersed on NaLTA zeolite, and the catalytic properties of CuO@NaLTA were investigated in the alkene epoxidation with H2O2 as oxidant in dioxane. For styrene oxidation, catalyst CuO@NaLTA exhibited excellent catalytic activities with 83 % conversion and 63 % selectivity to styrene epoxide, and could be easily recycled several times without obvious activity loss. The excellent catalytic activities could be attributed to the highly dispersed active CuO species. Besides, multiple electronic effects and coordinative interactions exited in Cu ion and the Si-Al zeolite skeleton framework played a key role in the catalytic recyclability.