Figure 4. Reusability of the aqueous phase containing catalysts and NaCl for glucose dehydration to HMF.

Reaction conditions: 10 wt% glucose in water (0.55 mmol), n (AlCl₃) = 0.025 mmol, pH = 2.5, NaCl/aqueous phase mass ratio of 0.4, CPME to water volume ratio of 3, reaction temperature of 175 °C, reaction time of 20 min.