Efficient synthesis of glycerol carbonate by doping metallic copper in palladium-catalyzed glycerol system for carbonylation reaction

Abstract

M–N–C materials derived from zeolitic imidazolium frameworks have exhibited remarkable efficacy as carriers for catalyzing glycerol carbonylation reactions, attributable to their meticulously modifiable pore size architecture, elevated catalytic selectivity, and commendable stability. In this study, we accomplished the successful integration of Cu²⁺ ions into the growth kinetics of ZIF-8 through a facile hydrothermal method. Subsequently, the resulting Cu–NC material was calcinated at 950 °C in a nitrogen atmosphere. This derived material served as an optimal substrate for the deposition of palladium nanoparticles, yielding the Pd/Cu–NC catalyst. The catalytic potential of this catalyst was evidenced by its superior efficiency in driving the glycerol carbonate synthesis from glycerol, surpassing the performance of the NC carrier in isolation. Impressively, a 98.3% yield and 99.7% selectivity were achieved within a mere 2-hour reaction span, conducted at 140 °C and 4 MPa. Employing density functional theory simulations, we delved into the intricate mechanisms governing carbonyl formation and ring closure during the oxidative carbonylation of glycerol. The strategic introduction of metallic copper during the initial phase of the transition state prominently underscored the robust interaction between copper and palladium. This interaction engendered a harmonized and systematically orchestrated charge distribution encircling the metallic palladium, thereby facilitating a more stable trajectory for ring formation processes.