Acid-catalyzed degradation of glucose in [EMIM]Cl. In acidic [EMIM]Cl, glucose (diamonds) disappears rapidly at 100 °C, forming HMF (squares) and other degradation products. Increased water content slows glucose loss. Reaction conditions: Glucose, 10 wt%; H2SO4, 4 wt% relative to glucose; H2O, 0–33 wt% relative to the total mass of the reaction mixture. Product levels are reproducible to within ± 4%.