Palladium Nanoparticle-Bentonite Hybrid Using Leaves of Syzygium aqueum Plant from India: Design and Assessment in the Catalysis of –C–C– Coupling Reaction

Abstract

An environment-friendly synthesis process has been developed with the aid of Syzygium aqueum (water apple) leaves extract. Pulverized leaves of Syzygium aqueum (water apple) are mixed with a universal solvent such as water for the preparation of Pd nanoparticle supported on activated Bentonite. The extract from the plant leaves acts both as a reducing agent and also as a capping agent for converting the PdCl2 to PdNPs. The synthesized PdNPs are supported on modified clay and they are characterized by using FTIR, BET, HR-TEM, ICP-MS, TGA, XRD, and FE-SEM/EDX. It is found that the supported PdNPs give high rate of conversions of Suzuki–Miyaura coupling products and give greater than 90% products in universal solvent i.e. water at fairly low temperature. It shows the potential for the environment-friendly synthesis of prime organic molecules like excellent biaryl derivatives with TONs and TOFs with economical and efficient catalyst loading. We recorded high activity, chemoselectivity and excellent TONs (15,061–20,537) and TOFs (100,407–136,919) by using a small catalyst loading in short reaction time only 15 min. The catalyst shows a long lifetime (ten times). Experiments are performed, recycling it, which demonstrate the sustainability and efficiency of the catalytic process. The prepared catalyst gives a higher percentage of coupling product in the lower time. The supported PdNPs help to form good selectivity and efficacy. The catalyst is found highly stable and can be recycled ten times with no appreciable loss in the efficiency. Graphical abstract