Pd4S Nanoparticles on Sulfur-Rich Hollow Carbons: Controlled Catalysts for Semi-Hydrogenation of Alkynes Even with Extended Reaction Times

초록

This work presents the development of an efficient new catalyst based on microporous organic polymer (MOP) chemistry for the selective semi-hydrogenation of terminal alkynes to alkenes. Various Pd-based coupling reactions are employed in MOP synthesis. Hollow MOPs (H-MOPs) are prepared through the Glaser coupling of 1,3,5-triethynylbenzene using 60 mol% (PPh3)2PdCl2, utilizing silica nanospheres as templates. The Pd catalysts are entrapped into the MOP networks. Post-synthetic modification with sulfur leads to the creation of sulfur-rich (23 wt.% sulfur) materials (H-SMOPs). Subsequent heat-treatment of H-SMOPs under argon results in the formation of Pd4S nanoparticles on hollow carbon supports enriched with 16 wt.% sulfur. The resulting H-SC@Pd4S catalyst demonstrates excellent selectivity for the semi-hydrogenation of both aryl and aliphatic terminal alkynes to styrenes (93-99%) and aliphatic alkenes (96-98%), respectively, maintaining the high selectivity for alkenes even with further extended reaction times of 6-16 h. Moreover, H-SC@Pd4S displays excellent recyclability over five consecutive runs, maintaining yields and selectivity.

키워드