Efficient Co/NSPC catalyst for selective hydrogenation of halonitrobenzenes and mechanistic insight

Abstract

The selective hydrogenation of halonitrobenzenes (HNBs) to haloanilines (HANs) is an efficient method to prepare key intermediates in the fine chemical industry. It is still a challenge to develop non-noble metal-based heterogeneous hydrogenation catalysts to achieve high activity and selectivity for this reaction. Herein, we reported a N, S co-doped mesoporous carbon supported Co catalyst for hydrogenation of HNBs, the prepared 5%Co/NSPC-800 catalyst showed superior catalytic performance with a TOF_s of 203 h⁻¹ and >99.9% selectivity to p-chloroaniline (p-CAN), and it also exhibited wide substrate applicability and can be reused at least 4 times. Furthermore, the reaction mechanism of p-CNB hydrogenation over 5%Co/NSPC-800 was proposed on the basis of kinetic studies, spectroscopic studies, and DFT calculations. The hydrogenation of p-CNB over 5%Co/NSPC-800 followed the condensation route, and Co⁰ and Co–N_x were the main active sites for this reaction.