Core‐shell microgel stabilized silver nanoparticles for catalytic reduction of aryl nitro compounds

Abstract

Silver nanoparticles loaded into shell of poly (styrene‐N‐isopropylmethacrylamide‐co‐acrylic acid) core shell [P (SNA‐CS)] gel particles were synthesized and analyzed by Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), ultraviolet–visible spectroscopy (UV–vis) and dynamic light scattering (DLS). Catalytic activity of Ag@P (SNA‐CS) particles was investigated by reducing p‐nitroaniline (p‐NA) into p‐aminoaniline (p‐AA) in the presence of sodium borohydride (NaBH4) reductant. Molecules of the substrate adsorbed on the surface of silver nanoparticles interact with borohydride ions (BH4−) to form p‐AA. Other nitroarenes like o‐nitroaniline (o‐NA), p‐nitrophenol (p‐NP) o‐nitrophenol (o‐NP), 2,4‐dinitrophenol(2,4‐DNP) were also reduced into their corresponding aryl amines using Ag@P (SNA‐CS) composite microgels as catalyst. Reported catalyst efficiently reduced the nitro aromatic compounds individually as well as simultaneously at ambient temperature. Effect of different reaction conditions (catalyst dose, concentration of NaBH4 and concentration of p‐NA) on reaction completion time, value of apparent rate constant (kapp) and reduction efficiency of the catalyst for reduction of p‐NA was also demonstrated. Ag@P (SNA‐CS) catalyst was found to be able to retain activity up to four cycles.