Green synthesis of Pd nanoparticles using Chlorella vulgaris plant extract on the surface of magnetic CQD for Suzuki cross coupling reaction

In the present study, the green synthesis of Pd nanoparticles by Chlorella vulgaris aqueous extract on the surface of magnetic carbon quantum dots have been developed. Carbon quantum dots were synthesized from date biochar and then magnetized with Fe3O4 magnetic nanoparticles. After that Pd nanoparticles were immobilized on the surface of magnetic carbon quantum dots via reduction of palladium ions with Chlorella vulgaris plant extract as a capping and reducing agent. To study catalytic activity of the prepared catalyst, the Suzuki- Miyaura cross-coupling reaction of phenyl boronic acid in H2O/EtOH as a green solvent was studied. After optimizing reaction condition, a variety of aryl halide with different functional groups were chosen as the substrate in the Suzuki-Miyaura cross-coupling reaction, which were performed well for all the examined substrate and the corresponding products were obtained in high yields. The reaction of aryl bromide and iodied with electron donating and electron‐withdrawing groups was generated the corresponding products in good to excellent yields with short reaction time. The coupling reaction of chlorobenzene with phenylboronic acid requires extended reaction time compared to aryl iodides and bromide and produced the desired product in moderate yield. Moreover, the leaching metal is a significant parameter for stability and industrial applicability of catalysts, to this end, the ICP technique was used. The amount of palladium loaded on the catalyst after 5 runs were found as 4.1 wt%, which was a slight change (4.8 wt %). The prepared nanocatalyst showed good catalytic performance after 5 times of use, so that it retained more than 94% of their activity even at the 5th run of catalytic reuse.

Keywords:

Magnetic CQD , Suzuki- Miyaura cross-coupling reaction , recycability