Enhanced Catalytic\nPerformance of Ru/Ammonium Oxalate\nCatalysts with Low Ru Content for Nonmercury Acetylene Hydrochlorination

As a promising alternative to HgCl<sub>2</sub> for acetylene\nhydrochlorination,\na novel catalyst of Ru/ammonium oxalate (NCO)-activated carbon (AC)\nwas developed, which shows approximately 90% conversion of acetylene\nand over 99% selectivity for the vinyl chloride monomer (VCM). In\ncomparison to the conventional Ru/AC catalyst, the amount of ruthenium\nchloride in Ru/NCO-AC was reduced to less than 0.2 wt %. In addition,\nthe coke deposition and Ru(0) generation were decreased by approximately\n18% and 50%, respectively. Characterizations indicated that the N-doped\nAC could inhibit the over-reduction of active Ru species and decrease\nthe coke deposition on the catalyst. Density functional theory calculations\nrevealed that NCO-AC could provide a synergistic environment for the\nRu-based catalyst. Acetylene molecules tend to be adsorbed on carbon\natoms adjacent to nitrogen atoms, which protects Ru(IV) from being\nreduced to Ru(0) and stabilizes the reactivity. The 0.95 eV energy\nbarrier of Ru/NCO-AC was much lower than that of a catalyst without\nN atoms (1.50 eV). Moreover, the low Ru content catalyst was placed\nin an industrial reactor and showed excellent activity during a 500\nh industrial experiment. These results may be helpful for designing\nefficient nonmercury catalysts and replacing existing HgCl<sub>2</sub> for the commercial application of acetylene hydrochlorination.