Behavior of adsorbed diphenyl-sulfide on the Pd/C catalyst for o-chloronitrobenzene hydrogenation

A series of diphenyl-sulfide (Ph2S)-immobilized Pd/C catalysts (Pd–Ph2S(x)/C) were prepared using the wetness-impregnation and immobilization method. Pd–Ph2S(x)/C catalysts employed for the hydrogenation of o-chloronitrobenzene showed very high selectivity. The structure of Pd–Ph2S(x)/C with different molar ratio of ligand (x-values) was characterized by XPS and TG–DSC–MS. The results suggest a “saturated” surface ratio of Ph2S/Pd (about 0.3) was formed on the Pd–Ph2S(x)/C catalysts surface. The Ph2S immobilized on the Pd particle is quite stable, and the desorption of Ph2S or dissociative loss of phenyl group was only found at temperatures above 500 K. The possible catalytic mechanism of the Pd–Ph2S(x)/C catalyst was also discussed.

Graphical abstractA diphenyl-sulfide (Ph2S)-immobilized Pd/C catalytic system (Pd–Ph2S(x)/C) was developed and employed for the hydrogenation of o-chloronitrobenzene showed very high selectivity. The possible mechanism for the enhanced selectivity of the Pd–Ph2S(x)/C catalyst was proposed.Figure optionsDownload full-size imageDownload as PowerPoint slide