A method for recycling the Pd catalyst at molar ppm level

Abstract Herein, we describe the preparation of poly(tetrafluoroethylene) (PTFE) materials, including a PTFE-coated magnetic stir bar and a PTFE vial, for the recycling of catalysts at the molar ppm level. Metal nanoparticles were consistently deposited onto the PTFE surface using straightforward and conventional techniques for nanoparticle formation. These metal nanoparticles deposits proved resistant to removal by simple washing methods. Upon reducing Pd(OAc) 2 with 4-methylphenylboronic acid in a 1.5 mol/L aqueous KOH solution at 90 °C for 1 h, nanoparticles approximately 100 nm in size, along with larger aggregates, were observed via SEM analysis of the PTFE-coated magnetic stir bar (8.0 mm × 1.5 mm). The reusability of the Pd nanoparticles-immobilized stir bar was suboptimal in Hiyama and Suzuki coupling reactions. However, the stir bar on which metal nanoparticles were sequentially deposited (Pd, Rh, and Pd) exhibited high recyclability over ten consecutive runs. Additionally, the PTFE vial, upon deposition of both Pd and Rh, was employed as a highly recyclable catalyst. Graphical Abstract