Ultralow Loading Cobalt-Based Nanocatalyst for Benign and Efficient Aerobic Oxidation of Allylic Alcohols and Biobased Olefins

Abstract

The synthesis of α,β-unsaturated ketones from aerobic oxidation of allylic alcohols and biobased olefins serves as an important topic in green and sustainable chemistry. In this work, we report the utilization of a sacrificial template ZIF-8 for preparation of mesoporous Co0.05/N–C material with an ultralow cobalt loading of 0.05 wt %, in which the excellent catalytic performance in aerobic oxidation of α-pinene and cinnamyl alcohol was achieved with an 85% yield of verbenone and a yield of cinnamaldehyde, respectively. The results of control experiments and several characterization investigations further illustrate that the sacrificial template ZIF-8 plays a key role to disperse well metallic cobalt in the Co0.05/N–C-800 catalyst and an appropriate cobalt content of 0.05 wt % is beneficial for benign and efficient aerobic oxidation of various allylic alcohols and biobased olefins. In addition, the Co0.05/N–C-800 catalyst also exhibited good stability and reusability for recovering and reusing at least six times without obvious decrease in catalytic activity. The presented efficient nanocatalyst thus triggers facile synthesis of a series of α,β-unsaturated aldehydes/ketones in high yields.