Solid acid catalyst prepared via one-step microwave-assisted hydrothermal carbonization: Enhanced stability towards intensified production of 5-hydroxymethylfurfural in water/γ-valerolactone/NaCl

Abstract In this study, carbon-based catalysts prepared via one-step microwave (MW)-assisted hydrothermal carbonization, functionalized with 2-hydroxyethylsulfonic acid (HESA) and hydrochloric acid (HCl), were tested on the intensified production of HMF from dehydration of glucose in biphasic system, consisting of water/γ-valerolactone/NaCl. The highest HMF yield (51.61%) was obtained when using 40/60 %v/v of water/ γ-valerolactone (GVL), C-SO3H catalyst loading at 0.5% by weight (%wt) of glucose, at 180°C for 45 min. In addition, the one-step preparation applying MW irradiation provided the catalyst with excellent reusability up to at least five times.