Enhanced flow electrochemistry for cyclohexane Conversion: From simulation to application

• Plug-flow electrocatalytic membrane reactor (PF-ECMR) was firstly constructed. • The state-of-the-art performance: 95.6% CHA conversion; > 99% selectivity to KA oil. • Excellent stability: 10-day run with > 90.6% CHA conversion and > 99% selectivity. • Auxo-action of the product was verified via DFT calculation and experiment. • Green synthesis with mild conditions: room temperature, 4.8 V, no oxidant required. To further improve the capability of flow electrochemistry, the multistage plug-flow electrochemical membrane reactor (PF-ECMR) with membrane electrode was developed for enhancing the oxidation of cyclohexane (CHA) to produce KA oil (mixture of cyclohexanol and cyclohexanone). The catalytic results demonstrated that the CHA conversion and the selectivity to KA oil were up to 95.6% and > 99%, which was the highest in comparison with most of the state-of-the-art catalytic processes reported in the previous works. The mechanism was explored by density functional theory (DFT) calculations, indicating the auxo-action effect of cyclohexanone was beneficial for the formation of cyclohexyl hydroperoxide so as to enhance the CHA conversion. The excellent performance of PF-ECMR was also attributed to the staggered electric field and the accumulative effect of the multi-electrodes. This study provided a successful case of a combination of theoretical prediction and experimental verification together for organic synthesis.