Sulfur-Promoted Hydrocarboxylation of Olefins on Heterogeneous Single-Rh-Site Catalysts

Abstract

Sulfur poisoning is a severe problem in industrial applications, attracting broad interest in fundamental research studies. Although a number of studies about sulfur resistance have been implemented in many reactions on nanoparticle catalysts, few investigations focus on carbonylation reactions using heterogeneous single-metal-site catalysts (HSMSCs). Herein, we present an unanticipated sulfur-promoted performance in olefin hydrocarboxylation reactions on a single-Rh-site catalyst supported on porous ionic polymers (Rh1/PIPs) with 1000 ppm H2S in CO feed. Ex situ EXAFS and in situ DRIFTS revealed a ternary cycle mechanism of olefin hydrocarboxylation reactions with Rh–H complexes as predominant active species in both pure and H2S-containing feedstock. Moreover, the transformation of the Rh mononuclear complex with the addition of H2S was also demonstrated. Density functional theory studies were performed to verify the feasibility of the proposed pathway and confirm that the energy barriers of transition states with the sulfur ligand were much lower than those in normal feed, for example, a decline of 3.4 kcal/mol for the rate-determining step of migration and insertion of CO. This work provides a distinctive example for the insight of sulfur effect on carbonylation, which could be potentially beneficial for further applications of HSMSCs.

Hydrocarboxylation of Olefins Catalyzed by Polyoxometalate-Anchored Palladium Single-Atom Catalysts

“…The carbonylation reaction is one of the important pathways in high-value utilization of C1 resources. − Hydrocarboxylation of alkenes to generate carboxylic acids has attracted much attention, as it represents a straightforward and 100% atom-economic method. − Meanwhile, the organic carboxylic acid compounds can be widely applied in the production of materials, food industry, or pharmaceutical intermediates. − Therefore, developing highly efficient and low-cost catalytic systems for the synthesis of carboxylic acids via olefin hydrocarboxylation is strongly desirable.…”

Palladium and Ruthenium Dual‐Single‐Atom Sites on Porous Ionic Polymers for Acetylene Dialkoxycarbonylation: Synergetic Effects Stabilize the Active Site and Increase CO Adsorption

“…In the 13 C MAS NMR spectrum of Figure S4a, the peak at 41.6 ppm was attributed to the saturated alkyl group (polymerized from the vinyl groups) and the signals ranging from 120 ppm to 150 ppm were attributed to aromatic carbon atoms on the fresh Pd 1 −Ru 1 /PIPs, indicating the successful polymerization of the 3 V‐Ph 3 P + MeI − monomer and the potential stability of the carbon skeleton during the reaction. The single signal at 20.0 ppm in the 31 P MAS NMR spectra of PIPs and the fresh Pd 1 −Ru 1 /PIPs (Figure S4b) was attributed to the P V species in quaternary phosphonium salts, indicating that the P specie was stable during the process of catalyst preparation [11] …”

“…The single signal at 20.0 ppm in the 31 P MAS NMR spectra of PIPs and the fresh Pd 1 À Ru 1 /PIPs (Figure S4b) was attributed to the P V species in quaternary phosphonium salts, indicating that the P specie was stable during the process of catalyst preparation. [11] To verify the molecular structure of Pd 1 À Ru 1 /PIPs, multiple characterization techniques, including XRD, TEM, HAADF-STEM, XPS, and EXAFS, were performed. In the XRD patterns of fresh Pd 1 À Ru 1 /PIPs (Figure S5), no characteristic peaks belonging to Pd or Ru nanoparticles (NPs) appeared, indicating that no large Pd or Ru NPs are present on the fresh catalyst.…”

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

“…Therefore, the interactional difference of sulfur species on nanoparticles and SMSCs may demonstrate different results in catalysis. [12] The regeneration or self-recovery from the sulfur poisoning of SMSCs and NPs is supposed to be different. The SMSCs have the potential to be self-recovered from sulfur poisoning, while it is difficult for NPs theoretically.…”