Design and Synthesis of Brønsted-Lewis Acidic Imidazole-Based Poly(ionic Liquid)s for Efficient Conversion of Corn...

The direct and efficient catalytic conversion of lignocellulosic biomass into high-value platform chemicals is a pivotal challenge for sustainable biorefining. A Brønsted-Lewis double-acidic imidazole-based poly(ionic liquid)s catalyst P([VIM-PS][AlCl₄]-[DVIM][Br₂]) was designed and synthesized by copolymerization reaction using a quaternary ammonium salt of vinylimidazole ([VIM-PS][AlCl₄]) functionalized with a sulfonic acid group and quaternized with AlCl₃ as a monomer and bis-imidazolium ([DVIM][Br₂]) as a crosslinking agent. This solid catalyst demonstrated exceptional performance in the one-pot conversion of raw corn stover into 5-hydroxymethylfurfural (HMF), achieving a high biomass conversion of 86.1% and a remarkable HMF yield of 43.5%, accompanied by a furfural yield of 28.8% from the hemicellulose fraction. Notably, the process exhibited excellent scalability, with the conversion and HMF yield remaining at 85.1% and 42.6%, respectively, upon a 30-fold scale-up. The catalyst also displayed broad applicability to various biomass feedstocks. Moreover, it could be reused for at least six cycles without significant loss of activity, underscoring its robustness. A comprehensive green chemistry metrics analysis highlighted the sustainability of the process, emphasizing the crucial roles of catalyst recyclability and solvent recovery in minimizing waste. This work presents a green, efficient, and scalable catalytic strategy for the integrated valorization of lignocellulosic biomass into valuable furanic compounds.