Polybenzoxazine intrinsically installed N-methylpyridinium iodide functions efficient organocatalyst for CO₂ fixation into cyclic carbonate

Polybenzoxazine containing N-methylpyridinium iodide (PBz-[PyMe]I) was first utilized as an efficient catalyst for CO₂ fixation into cyclic carbonates. The polymer structure was determined as a phenolic-type polybenzoxazine characterized by FT-IR, ¹H NMR. PBz-[PyMe]I shows a wide scope of substrates for the reaction of cycloaddition of CO₂ with epoxides including aliphatic epoxides, styrene oxide derivatives, glycidyl ethers, and spiro-epoxyoxindole at 120 °C within two hours, and obtains high yields up to 96%. The catalyst was recycled up to four times remaining 82% catalytic activity comparing to the first run. A combined hydrogen-bonding mechanism activated by both phenol and pyridinium salt was proposed and verified. The synthesis and application of PBz-[PyMe]I suggested the viability of other catalytic moieties could be introduced into polybenzoxazine.