Hydrophobic Poly(divinylbenzene) Polymer-Supported Ruthenium Catalysts for Efficient Hydrogenation of Pyridines in Water.

Gas-liquid-solid triphase reactions are limited by poor gas solubility and mass transfer, especially in water. The low solubility of hydrogen in water severely hinders the hydrogenation, therefore requiring high temperature and pressure to increase the activity, which have safety and cost concerns. Herein, we report a hydrophobic poly(divinylbenzene) polymer-supported Ru nanoparticle catalyst (Ru/PDVB) with both high activity and excellent stability for the hydrogenation of pyridines in water, even at ambient hydrogen pressure (0.1 MPa). The average turnover frequency (ATOF) of the Ru/PDVB (836.8 mol molRu -1 h-1) is about 6.0 and 768.0-fold higher than those of traditional Ru/C and commercial Raney Ni catalysts under equivalent reaction conditions. Mechanistic studies reveal that the hydrophobic polymer prevents filling of water in the nanopores of PDVB, allowing hydrogen enrichment to boost the hydrogenation. This work provides an opportunity to improve the efficiency of industrially important reactions that suffer from poor gas solubility and mass transfer.