Fabrication of silver nanoparticles within chitosan based microgels for catalysis

Chitosan based monodisperse poly[chitosan-N-isopropylmethacrylamide-acrylic acid] [P(CNA)] microgels were produced via precipitation polymerization. Resulting crosslinked P(CNA) micro particles were used as micro-reactors to prepare silver nanoparticles within the polymeric network by chemical reduction of Ag+ ions with sodium borohydride. Various techniques including transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and ultraviolet-visible (UV-vis) spectroscopy were used to analyze P(CNA) microgels and Ag-P(CNA) hybrid microgels. Catalytic potential of Ag-P(CNA) hybrid system towards individual and simultaneous reduction of various nitroarenes like p-nitrophenol (pNP), o-nitrophenol (oNP), p-nitroaniline (pNA) and o-nitroaniline (oNA) into corresponding aminoarenes using sodium borohydride as a reductant in aqueous medium was evaluated. The catalytic activity of Ag-P(CNA) system towards both the individual and simultaneous reduction of nitroarenes was examined at various concentrations of catalyst. The values of pseudo first order rate constant (k1) for reduction of individual nitroarene and multiple nitroarenes were determined for comparison. The Ag-P(CNA) hybrid microgel system was found to be stable, economical and efficient catalyst for rapid individual and simultaneous reduction of nitroarenes.

Automated summary

Chitosan based monodisperse poly[chitosan-N-isopropylmethacrylamide-acrylic acid] [P(CNA)] microgels were synthesized and used as micro-reactors to prepare Ag-P(CNA) hybrid microgels via chemical reduction of Ag+ ions. The resulting hybrid microgels were characterized by TEM, FTIR spectroscopy, and UV-vis spectroscopy. The catalytic potential of the Ag-P(CNA) hybrid system for the reduction of nitroarenes was evaluated using sodium borohydride as a reductant in aqueous medium. The Ag-P(CNA) hybrid microgel system exhibited stable, economical, and efficient catalytic activity for the rapid reduction of nitroarenes both individually and simultaneously.