Sulfur-doped porous carbon supported palladium catalyst for high selective o-chloro-nitrobenzene hydrogenation

Sulfur-modified carbon support can effectively modulate the performance of the metal catalyst. Here we prepared a sulfur-doped mesoporous carbon material (CSx) through carbonization of poly(sodium p-styrenesulfonate or p-styrenesulfonate co-maleate), which was supported with Pd and employed for the selective hydrogenation of o-chloro-nitrobenzene (o-CNB) to o-chloro-aniline (o-CAN). Such catalyst shows almost 100% selectivity of o-CAN at 100% o-CNB conversion (performed In a batch reactor: t = 210 min, No-CNB/m(cat) = 0.63 mol/g(cat)). The stability (recyclability) study of the optimal catalyst shows that the catalyst can be reused for at least six times without decreasing the selectivity (100% conversion can be achieved with slightly prolonged reaction time). We suggest that the electronic effect between the S and Pd, which reduces the hydrogen adsorption and dissociation ability of Pd, to be responsible for the excellent selectivity, and the formation of C-S covalent bond to be responsible for the good stability.