In situ stabilization of Pd(0) nanoparticles into a mixture of natural carbohydrate beads: A novel and highly efficient heterogeneous catalyst system for Heck coupling reactions

Abstract

A convenient, mild and cost‐effective synthesis of palladium nanoparticles stabilized by a mixture of natural carbohydrate beads (gum arabic and pectin) as a new bio‐organometallic catalyst is reported. Powder X‐ray diffraction, transmission and scanning electron microscopies and energy‐dispersive X‐ray and UV–visible spectroscopies were employed to characterize this supported Pd nanoparticles/gum arabic/pectin catalyst. The nanocatalyst exhibited efficient activity in Mizoroki–Heck cross‐coupling reactions between various aryl halides and n‐butyl acrylate under solvent‐free conditions. The catalyst can easily be recovered from the reaction system and reused several times with high yields. The products were obtained in short reaction times with excellent yields.

Pd supported on locust bean gum as reusable green catalyst for Heck and Sonogashira coupling reactions and 4‐nitroaniline reduction under ultrasound irradiation

“…Different supports have been proposed in the coupling reaction such as synthetic silica‐based supports, [ 9 ] metal oxides, [ 10 ] carbon nanotubes, [ 11 ] and ionic liquids. [ 12 ] However, different synthesis teams have examined the possibility of replacing these with more environmentally friendly natural supports such as cellulose, PLA, gum arabic, [ 13–15 ] hyperbranched polytriazoles, [ 16 ] guar gum, [ 17 ] pectin, [ 18 ] gelatin, [ 19 ] and pectin/gelatin. [ 20 ]…”

“…Likewise, these supports can act as palladium reducer that never requires the use of ligand. [ 15–20 ] Gelatin‐supported Pd nanoparticles, for example, have been reported by Ghaderi's team [ 11 ] in Sonogashira coupling reaction using various iodides, bromides, aryl chlorides, and heteroaryl halides with phenylacetylene without copper and without ligand. The reactions were carried out at 100°C in molten tetrabutylammonium bromide (TBAB) or polyethylene.…”

An efficient and new protocol for the Heck reaction using palladium nanoparticle‐engineered dibenzo‐18‐crown‐6‐ether/MCM‐41 nanocomposite in water

“…The Pd‐catalysed cross‐coupling reactions, especially Heck arylation of olefins with aryl halides, are simple, efficient and versatile routes to the formation of carbon–carbon bonds commonly used in modern organic synthesis . For excellent performance of Pd‐catalysed processes, use of high‐activity Pd catalysts and green reaction conditions are two important strategies for the design of new heterogeneous Pd catalytic systems …”

Novel CuFe2O4@SiO2‐OP2O5H magnetic nanoparticles: Preparation, characterization and first catalytic application to the synthesis of 1,8‐dioxo‐octahydroxanthenes

“…Replacement of homogeneous catalysts with environmentally benign and reusable solid heterogeneous catalysts is an active area of current research . Nanoparticles as solid heterogeneous catalysts have attracted much attention because of their interesting structural features and high levels of catalytic activity.…”