High selectivity continuous production of isosorbide from sorbitol via reactive distillation

Isosorbide, a bio-based diol derived from sorbitol, is a promising alternative to bisphenol A (BPA) in polymer manufacturing, yet its large-scale production remains limited by diffusion constraints, secondary dehydration, and energy-intensive separation. In this work, we develop a continuous, high-selectivity process for isosorbide synthesis using a heterogeneous azeotropic catalytic distillation strategy. A direct-pump feeding system enables the continuous introduction of high-viscosity sorbitol without dilution, while an ion-exchange resin catalyst provides efficient dehydration under intensified reaction–separation conditions. Nearly complete sorbitol conversion (∼100 %) and 91.2 % isosorbide selectivity were achieved. Temperature-dependent LHHW kinetic modeling reveals that equilibrium shifting through continuous water removal, rather than mass-transfer limitations, governs selectivity enhancement. Process simulation further establishes a scalable three-column azeotropic catalytic distillation design capable of producing 10,000 tons per year, supported by favorable thermal and economic performance. This study demonstrates a practical and energy-efficient route for industrial isosorbide production and provides mechanistic and design guidance for future process scale-up.