Ionic quaternary ammonium-triazole polymers as efficient single-component catalysts for CO2 conversion

Ionic organic polymers with halide counterions have been investigated as effective and reusable single-component, heterogeneous catalysts for the cycloaddition of CO₂ and epoxides to form cyclic carbonates. In this study, we synthesized three new ionic polymers featuring quaternary ammonium-triazole functional groups with iodide counterions. Copper-catalyzed azide-alkyne cycloaddition (CuAAC) between tetrapropargylammonium bromide and various diazide compounds (N 3 –Ar–N 3 ), where Ar represents 1,4-xylene, 1,5-naphthalene, and 4,4′-phenylbenzamide followed by halide exchange, afforded the organic polymers QAP1 – 3 , respectively. The formation of triazole moieties and the disappearance of azide functional groups were confirmed by 13 C CP/MAS NMR and FT-IR spectroscopy, respectively. CO 2 sorption studies showed reduced adsorption capacities compared to neutral amine analogs. The xylene-linked polymer ( QAP1 ) exhibited the highest catalytic efficiency for CO 2 /epoxide cycloaddition, achieving high conversion and selectivity under 10 atm CO 2 at 120 °C. Reusability study showed that QAP1 could be reused for four cycles with minimal loss in activity, though some thermal decomposition of quaternary ammonium groups was observed in solution. • Ionic polymers with quaternary ammonium bromide-triazole cores were synthesized. • The xylene-linked polymer catalyst exhibited high CO 2 /epoxide cycloaddition activity. • Ionic polymers showed lower CO 2 uptake than neutral amine counterparts. • Partial thermal decomposition of the polymer catalysts was observed at 120 °C.