The Effect Of Sulfides On The Hydrogenation Performance Of Platinum Group Metal Catalyst

Supported Pt, Pd and other noble metal catalysts were widely used in organic reactions for the characteristics of high activity and easy separation. However, in liquid chemoselective hydrogenation of organic compounds with various reducible functionalities, it was diffcult to meet the high selectivity requirements for over-hydrogenation reactions resulted from high catalytic activity of these catalysts. It was an effective way to improve the selectivity of these noble metal catalysts by Sulfuration treatment.A series of Pd-S/C catalysts were prepared from Pd/C by treating with different sulfide agents in the present thesis, and the reductive alkylation between N-phenyl-p-phenylenediamine and aliphatic ketones were used as a probe reaction to investigate the catalytic performance of these Pd-S/C catalyst. The effects of sulfides sort, sulfides amounts used to treat Pd/C and reaction conditions on the catalytic performance of these Pd-S/C catalysts had been investigated systematically, catalytic performance of these Pd-S/C catalysts was also compared with Pd/C in the probe reaction. It was found that Pd-S/C prepared from Pd/C by treating with diphenyl sulfide showed the best catalytic performance by increasing the yield of the Disired product s in the probe reaction substantially, in which the conversion of N-phenyl-p-phenylenediamine was 96.43%, and the selectivity of Disired product was 96.35%.XRD and XPS characterization were used to analyze Pd-S/C catalysts prepared from Pd/C by treating with diphenyl sulfide, the results showed that strong chemical bonds were formed between diphenyl sulfide, but the formation of these chemical bonds did not have significant effect on the Pd lattice, a part of Pd combined with diphenyl sulfide lost 4 electrons presented the state of +4, and the other part of Pd did not combined with diphenyl sulfide existed in the form of elemental palladium atoms and PdO species.