Macroporous hollow silica microspheres-supported palladium catalyst for selective hydrogenation of nitrile butadiene rubber

Abstract A potential high durable heterogeneous catalyst for the industrial selective hydrogenation of nitrile butadiene rubber (NBR) has been established by immobilizing palladium (Pd) nanoparticles on macroporous hollow silica (MHS) microspheres in the present work. Compared with the Pd nanoparticles supported on macroporous hollow silica (Pd/MHS) via conversional incipient wetness impregnation with different free chelating reagents (HCl or EDTA) catalysts, the Pd nanoparticles supported on the modified macroporous hollow silica (Pd/M-MHS) catalyst showed better distribution of Pd nanoparticles and catalytic performance. High hydrogenation degree (HD) toward the –CH CH– group of 97% was achieved in acetone solution at 70 °C with H 2 pressure of 4.5 MPa for 6 h, while the nitrile (–C N) group had not been hydrogenated in the reaction. And there was no obvious change in the relative molecular weight and polydispersion index of the product in comparison with the raw NBR. The HD for the 5th reuse was 90.5%, remaining more than 93% of its HD for the original time, demonstrating its high durable activity.