A comparative study of catalytic activity on iron-based carbon nanostructured catalysts with Pd loading: Using the Box-Behnken design (BBD) method in the Suzuki-Miyaura coupling

Highly dispersed palladium nanoparticles immobilized on surface-modified Fe3O4 NPs and magnetic carbon nanostructures (CNSs; carbon nanotubes/graphene oxide) were synthesized and applied as a recyclable and reusable nanocatalyst to achieve palladium (II)-catalyzed Suzuki-Miyaura reaction of arylboronic acid with aryl bromides. Carbon nanostructures with immobilized hydantoin (PH)-Pd complex display excellent stability, including a high performance at low catalyst loading. Magnetic separation prevents catalyst centrifuge or filtration and also contributes to practical techniques for recovery. Next, a response surface method based on a three-level Box-Behnken design was used, which involved three factors: catalyst loading, reaction time, and solvent. The Box-Behnken method was advantageous to parameters optimization for obtaining a yield, with high efficiency and accuracy. As a result of catalytic tests, the TONs and TOFs were calculated from all coupling reactions. The prepared nano-magnetic catalysts, after the catalysis reaction, can be easily recovered through the magnetic field. Evaluated catalytic performance indicates that these types of catalysts can function as effective recyclable catalysts at least five times without losing the initial level of catalytic activity.