Highly efficient dehydration of fructose to 5-hydroxymethylfurfural over carbon beads supported ionic liquid catalysts in micropacked bed reactors

Highly efficient HMF synthesis was realized in μPBRs over ACB18-Si-ILs. • HMF (90.8%) or LA (65.2%) was selectively produced in μPBRs within 252 s. • ACB 18 -Si-ILs stably catalyzed fructose conversion to HMF in μPBRs for 1440 min. • Product yields in μPBRs were predicted by an intrinsic kinetic model. • LHHW kinetic analysis identified the surface reaction as the rate-determining step. In this work, acidic ionic liquids (ILs) were immobilized on activated carbon beads (ACB) with a particle size of 0.3 mm (ACB 18 -Si-ILs), and combined with micropacked bed reactors (μPBRs) to achieve continuous and long-term conversion of fructose to 5-hydroxymethylfurfural (HMF). After pretreatment, the specific surface area of ACB reached 1249.4 m 2 /g, and the ionic liquid was chemically bonded to the support, exhibiting good stability. Selective production of HMF and levulinic acid (LA) was achieved through reaction optimization and solvent regulation, achieving a yield of 90.8% HMF or 65.2% LA within 252 s in μPBRs. The space-time yield of HMF and LA were both increased by an order of magnitude compared to traditional reactors, and the HMF yield maintained over 85% after 1440 min continuous operation. A heterogeneous intrinsic kinetic model was established for predicting product yield in μPBRs, with the error controlled within ±15%. Under the intrinsically kinetic controlled regime, the Langmuir-Hinshelwood-Hougen-Watson model was constructed, identifying the catalyst surface reaction as the rate-limiting step. The adsorption constants of fructose and HMF were obtained and the catalyst surface reaction rate was predicted with an error less than ±10%. Download: Download high-res image (167KB) Download: Download full-size image