Sulfur Poisoning and Self‐Recovery of Single‐Site Rh1/Porous Organic Polymer Catalysts for Olefin Hydroformylation

Abstract

AbstractSulfur poisoning and regeneration are global challenges for metal catalysts even at the ppm level. The sulfur poisoning of single‐metal‐site catalysts and their regeneration is worthy of further study. Herein, sulfur poisoning and self‐recovery are first presented on an industrialized single‐Rh‐site catalyst (Rh1/POPs). A decreased turnover frequency of Rh1/POPs from 4317 h−1 to 318 h−1 was observed in a 1000 ppm H2S co‐feed for ethylene hydroformylation, but it self‐recovered to 4527 h−1 after withdrawal of H2S, whereas the rhodium nanoparticles demonstrated poor activity and self‐recovery ability. H2S reduced the charge density of the single Rh atom and lowered its Gibbs free energy with the formation of inactive (SH)Rh(CO)(PPh3‐frame)2, which could be regenerated to active HRh(CO)(PPh3‐frame)2 after withdrawing H2S. The mechanism and the sulfur‐related structure–activity relationship were highlighted. This work provides an understanding of heterogeneous ethylene hydroformylation and sulfur‐poisoned regeneration in the science of single‐atom catalysts.