Mo(VI) Schiff base complex immobilized on graphene oxide nano‑sheets as an efficient, selective and reusable catalyst for epoxidation of olefins

Heterogenization of homogeneous catalysts onto solid supports has been studied because of the long catalytic lifetime, easy separation, thermal stability, high selectivity, and easy recyclability [1]. For the heterogenization of homogeneous catalysts, which suffer from drawbacks such as deactivation, difficult recovery and difficult recycling, graphene oxide (GO) is a convenient and efficient supporting material [2].In this work Mo(VI) tetradentate Schiff base complex was covalently immobilized onto chemically functionalized graphene oxide (GO) using 3-aminopropyltriethoxysilane as a coupler. The resulting heterogeneous catalysis has been characterized by FTIR, XRD, SEM, DRS, TGA, and inductively coupled plasma-atomic emission spectroscopy (ICPAES). Catalyst was used for the selective epoxidation of alkenes using tert-butyl hydroperoxide as oxidant. This catalyst is efficient for oxidation of cyclooctene with a moderate 100% selectivity for epoxidation with 98% conversion in 30 min. The recycling experiment results indicated that the catalyst was highly stable and maintained very high activity, and selectivity even after being used for five cycles.