Synthesis and Application of Bifunctional Porous Polymers Bearing Chloride and Sulfonic Acid as Cellulase-Mimetic Solid Acids for Cellulose Hydrolysis

A two-step strategy was demonstrated to synthesize porous polymeric solid acids with bifunctionality (chloride and sulfonic acid) to mimic cellulase for hydrolyzing cellulose. The solid acids were synthesized from aromatic monomers bearing chloride through Friedel-Crafts polymerization and then sulfonated with fuming sulfuric acid to introduce sulfonic acid. The chloride and sulfonic acid were expected to function as the cellulose-binding group (CBG) and the cellulose-hydrolytic group (CHG), respectively. It was found that the synthesized cellulase-mimetic solid acids were more effective in hydrolyzing microcrystalline cellulose (Avicel) than non-cellulase-mimetic solid acid (Amberlyst 15) and sulfuric acid at the same acid loading. Ball-milled Avicel could be hydrolyzed by up to 84.9 % by the cellulase-mimetic solid acids. The performance of the solid acids was supposedly attributed to the synergetic roles of the CBG and the CHG and the porous structure of the synthesized solid acids.