Mechanochemistry Unlocks direct cellulose conversion to 5-Hydroxymethylfurfural

Develop AlCl 3 -assisted mechanochemical strategy enabling efficient one-pot conversion of recalcitrant cellulose to HMF. • Synergistic interplay between Lewis acidity and mechanical stress disrupts H-bonding networks and lowers crystallinity, markedly enhancing the chemical reactivity of cellulose. • Optimization of the Brønsted/Lewis acid balance by controlled HCl addition achieves a high HMF yield of 62.8% from mechanochemically pretreated cellulose. • This green and scalable approach can be broadly extended to diverse lignocellulosic biomass wastes, including waste paper, corncob residue, bamboo powder, and corn straw, to efficiently produce HMF. 5-Hydroxymethylfurfural (HMF) is a pivotal bio-based platform chemical, yet its direct production from inexpensive and abundant cellulose remains challenging due to the intrinsic recalcitrance of cellulose and the competing degradation of intermediates and products under acidic conditions. Herein, we report an AlCl 3 -assisted mechanochemical strategy that couples catalytic Lewis acidity with ball-milling mechanical force to activate cellulosic feedstocks, enabling their efficient one-pot conversion to HMF. Detailed structural characterizations demonstrate that the synergistic interplay between AlCl 3 and mechanical stress disrupts the extensive hydrogen-bonding network and partially cleaves β-1,4-glycosidic linkages, leading to pronounced reductions in cellulose crystallinity and degree of polymerization and, consequently, markedly enhanced chemical reactivity. The resulting mechanochemically pretreated cellulose (BMM-AlCl 3 ) was directly converted into HMF without additional catalysts during the reaction step, as the Al species introduced during pretreatment served as the catalytic sites, affording a yield of up to 46.8%. By further optimizing the Brønsted/Lewis acid balance through controlled HCl addition, the HMF yield increases to 62.8%. Importantly, this pretreatment strategy is broadly applicable to diverse lignocellulosic biomass resources, including waste paper pulp, corncob residue, bamboo powder, and corn straw, consistently delivering high HMF yields. This work establishes an efficient and potentially scalable mechanochemical route for the valorization of cellulose and lignocellulosic biomass into HMF. Download: Download high-res image (185KB) Download: Download full-size image