Synthesis, characterization and catalytic application of silver nanoshell coated functionalized polystyrene beads.

Silver nanoshell coated cationic polystyrene beads have been synthesized at room temperature through immobilization of specific silver precursor ions followed by wet chemical reduction technique. Electrostatic field force has been taken into consideration for the immobilization of precursor ions onto the resin beads. The as-synthesized particles were characterized by XRD, XPS, SEM, EDX, and FTIR studies. The silver coated resin beads have been exploited as a solid phase catalyst to reduce 4-nitrophenol in presence of sodium borohydride. The detailed kinetics of the reduction process was monitored under varied experimental conditions. At the end of the reaction, the catalyst particles remain active, get separated from the product, 4-aminophenol and can be recycled for a number of times after the quantitative reduction of 4-nitrophenol. The activity of the solid-catalyst particles has been examined towards the reduction of other nitrophenols e.g., o-, m-nitrophenol and also for 2,4,6-trinitrophenol. The synthesis of anthranilic acid from o-nitrobenzoic acid has also been achieved using the composite materials as catalyst. The synthesis of the solid phase catalyst particles, their application and detailed kinetic aspects of the reduction of 4-nitrophenol have been reported.