Investigation of the Deactivation and Reactivation Mechanism of a Heterogeneous Palladium(II) Catalyst in the Cycloisomerization of Acetylenic Acids by In Situ XAS

Abstract

A well-studied heterogeneous palladium(II) catalyst used for the cycloisomerization of acetylenic acids is known to be susceptible to deactivation through reduction. To gain a deeper understanding of this deactivation process and to enable the design of a reactivation strategy, in situ X-ray absorption spectroscopy (XAS) was used. With this technique, changes in the palladium oxidation state and coordination environment could be studied in close detail, which provided experimental evidence that the deactivation was primarily caused by triethylamine-promoted reduction of palladium(II) to metallic palladium nanoparticles. Furthermore, it was observed that the choice of the acetylenic acid substrate influenced the distribution between palladium(II) and palladium(0) species in the heterogeneous catalyst after the reaction. From the mechanistic insight gained through XAS, an improved catalytic protocol was developed that did not suffer from deactivation and allowed for more efficient recycling of the catalyst.

Keywords

X-ray absorption spectroscopy; cycloisomerization; deactivation/reactivation; heterogeneous; palladium catalysis

Published in

ACS Catalysis
2021, volume: 11, number: 5, pages: 2999-3008
Publisher: AMER CHEMICAL SOC

SLU Authors

• Yuan, Ning

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    
  • Stockholm University

• Persson, Ingmar

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

• Bajnóczi, Eva

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    
  • Hungarian Academy of Sciences

UKÄ Subject classification

Physical Chemistry

Publication identifier

• DOI: https://doi.org/10.1021/acscatal.0c04374

Permanent link to this page (URI)

https://res.slu.se/id/publ/111516