Ionic Liquid Hydrogels Based on Poly(2-acrylamido-2-methyl-1-propanesulfonic Acid -co-1-vinylimidazole): A Green and Efficient Catalyst Carrier for Ag Nanoparticles in Oxidation and Adsorption of Benzyl Alcohol in Water

Radical polymerization reactions were employed to synthesize poly(2-acrylamido-2-methyl-1-propanesulfonic acid - co -1-vinylimidazole), hydrogels at neutral and acidic reaction conditions. The results of Fourier Transform Infrared (FT-IR) spectroscopy and scanning electron microscopy spectroscopy confirmed the chemical composition of the synthesized hydrogels. Loading Ag into hydrogels, removing loosely-bound Ag ions, and reducing Ag ions with sodium borohydride (NaBH 4 ) were used to construct p(AMPS-Na + - co -VIm)-Ag and p(AMPS-H + - co -VIm)-Ag. Metal nanoparticles embedded p(AMPS-Na + - co -VIm)-Ag and p(AMPS-H + - co -VIm)-Ag were visualized by high resolution X-ray photoelectron spectroscopy, transmission electron microscopy and energy dispersive X-ray. FT-IR spectroscopy and HR-XPS demonstrated that the interaction of network heteroatoms with Ag nanoparticles was responsible for stabilizing silver nanoparticles. Atomic absorption spectroscopy was also employed to measure the concentrations of metals in all compounds. P(AMPS-Na + - co -VIm)-Ag and p(AMPS-H + - co -VIm)-Ag composites were used as catalyst in the oxidation of alcohols by emphasizing the effects of different parameters such as oxidant, substituent effect, etc. The prepared porous hydrogels and related composites were also utilized in the adsorption of Benzyl alcohol from aqueous solutions. P(AMPS-Na + - co -VIm) and its composite has better performance than p(AMPS-H + - co -VIm) and p(AMPS-H + - co -VIm)-Ag. Because, absorption capacity is increased with an increase in the high porosity and it is depending on porous size and shapes. In continue, quaterniztion effect by 1,4-dibromobutane on catalytic performance of nano-composites was investigated. The results confirmed the easy separation of the prepared catalysts from the reaction media. Moreover, the catalysts could efficiently be recycled four times without losing their quality. It was also proved that the catalysts were recyclable, durable, and leaching-resistant. Graphical Abstract