The hydrolysis of cellulose was catalyzed over a variety of acidic ionic liquids (ILs). It is found that the hydrolysis activity is directly associated with the acidity of catalysts, as evidenced by IR spectroscopy. C-13 NMR characterization results confirm the majority product of cellulose hydrolysis is glucose, and the resulting carbohydrates undergo further degradation, possibly also catalyzed by the acidic ILs, to 5-hydroxymethylfurfural (HMF). Moreover, in situ C-13 NMR measurements clearly exhibit that the evolution of products is dependent on the reaction process. we attempt to study the kinetics of cellulose hydrolysis over the most active catalyst of [C(4)SO(3)Hmim]HSO4 at different temperatures (80-120 degrees C) to obtain the important kinetic parameters such as apparent activation energies of consecutive reaction steps. (C) 2010 Elsevier B.V. All rights reserved.