Hydrogen-bonding network mediated highly efficient and selective sorbitol dehydration catalyzed by deep eutectic solvent

The catalytic dehydration of sorbitol to isosorbide is a key route for the sustainable production of bio-based platform chemicals, yet low product yield and severe side reactions remain critical challenges. In this work, how the hydrogen-bonding network of deep eutectic solvents (DESs) mediates the highly efficient and selective sorbitol dehydration was investigated. Among different DESs, betaine/methanesulfonic acid (Bet-MSA) with 1.0:1.1 molar ratio shows a maximum isosorbide yield of 85.03% under optimized conditions. The strong hydrogen-bonding network within DESs effectively activates sorbitol molecules, stabilizes reaction intermediates, and lowers the activation energy of the desired pathway, thereby enhancing catalytic selectivity. The non-steady state kinetic model can well predict the concentration changes of key components, in which Bet-MSA contributes to lower activation energy for the desired sorbitol formation pathway through the hydrogen-bonding interactions, thereby enhancing selectivity. This work provides mechanistic insights for the design and optimization of industrial sorbitol dehydration processes.