Ag-Nanocatalysts Based on Porous Organic Polymers in Chemical Fixation of CO2 for the N-Methylation and N-Formylation of Amines

Chemical fixation of CO2 for the synthesis of valuable chemicals is very demanding in the context of green and sustainable chemistry. Herein, we report highly efficient silver-loaded porous organic polymer catalysts for the exclusive N-formylation and N-methylation of amines under ambient reaction conditions using CO2 as a green C1 source. By adjusting the solvent and temperature of the reaction, the successful production of formamides and methylamines could be accomplished with high levels of selectivity and efficiency. POP-based materials Ag@TTP-1 and Ag@PAN-T are utilized as low-cost catalysts for both the N-methylation and N-formylation of primary and secondary amines and the product yields up to 98 % could be achieved. Ag@TTP-1 demonstrated superior catalytic efficiency compared to Ag@PAN-T in the N-methylation and N-formylation reactions. This result suggests that the grafting of Ag nanoparticles onto POP surface with a high surface area plays a crucial role in these CO2 fixation reactions. The above-mentioned catalysts (Ag@TTP-1 and Ag@PAN-T) are characterized through powder XRD, FT IR spectroscopy, FE-SEM, TEM, thermogravimetric techniques, N-2 sorption and XPS analysis. Ag-nanocatalysts demonstrated heterogeneous nature and high recycling efficiency for several cycles in this CO2 fixation reaction.