Coupling Carbon Dioxide and Cyclohexane Oxide Using Metal-Free Catalyst with Tunable Selectivity of Product Under Mild Conditions

This study introduces a metal-free binary catalytic system for coupling CO2 with cyclohexane oxide (CHO) under mild conditions, allowing for tunable product selectivity. Using trans-cyclohexane diol (trans-CHD) and phosphazene superbase (P4) as catalysts, the system selectively produces cyclic carbonates and oligocarbonates at 1 bar CO2 pressure and 80 °C. By adjusting the catalyst ratio, varying proportions of cis-cyclohexane carbonate (cis-CHC), trans-cyclohexane carbonate (trans-CHC), and oligocarbonate are achieved, with 51 mol% CHO conversion and respective selectivities of 36%, 31%, and 33%. The catalytic efficiency and precise control of product outcomes underscore this system’s potential.