Investigating Hydrogenation of Aldehyde and Heck Reaction on the Surface of Recyclable Palladium Decorated Functionalized Mica

Palladium nanocrystals (Pd_NCs) were synthesized and immobilized on functionalized mica (Pd_NCs@FM). Pd_NCs@FM was used for catalyzing C–C coupling reaction. Preliminary, the activities of both palladium nanocubes/octahedra immobilized on functionalized mica (Pd_c@FM/Pd_o@FM) were investigated through probe reaction (hydrogenation of benzaldehyde: BzH). Probe reactions revealed that Pd_o@FM was highly active for hydrogenation of BzH to benzyl alcohol (BzOH) (yield: > 99% and selectivity > 96%). TEM images reflect uniform distribution of nanocrystals (NCs) on the surface of functionalized mica (FM) with ≈ 8% poly dispersity while SEM confirms smooth morphology of the catalyst. The average size of the NCs was 7–10 nm, while bulk particle size of Pd_NCs@FM was in the range 149–177 μm. Surface area of FM and Pd_NCs@FM was 71+ and 59m²/g, respectively. The Pd_o@FM efficiently catalyzed Heck reaction of ethyl-benzimidazole acetate with bromobenzene to yield 99% isolated ethyl 2-(2-phenyl-1H –benzo [d]imidazole-1-yl) acetate. DFT study indicate that the ethyl-benzimidazole acetate (BZ) strongly anchored with the palladium decorated functionalized mica surface, evince the high catalytic activity of the catalyst. It was confirmed that Pd_NCs@FM can be effectively used for hydrogenation of aldehyde/ketone and C–C coupling reactions.