Direct conversion and NMR observation of cellulose to glucose and 5-hydroxymethylfurfural (HMF) catalyzed by the acidic ionic liquids

• Published in: Journal of molecular catalysis. A, Chemical Chemical, 2011-01, Vol.334 (1-2), p.8-12
• Main Authors: Jiang, Feng, Zhu, Qingjun, Ma, Ding, Liu, Xiumei, Han, Xiuwen
• Format: Article
• Language: English
• Subjects: Acidic catalysis; Apparent activation energy; Catalysis; Chemistry; Exact sciences and technology; General and physical chemistry; Hydrolysis of cellulose; In situ13C NMR; Ionic liquids; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry
• ISSN: 1381-1169; 1873-314X
• DOI: 10.1016/j.molcata.2010.10.006

Cellulose was converted to glucose and 5-hydroxymethylfurfural under acidic ILs catalyst with high yield. In situ13C NMR was used to follow the reaction, prompting our understanding on this important process. [Display omitted] ▶ The acidic ionic liquid [C4SO3Hmim]HSO4 is an effecient catalyst for the hydrolysis of cellulose. ▶In-situ13C NMR is an effective characterization technique to study the cellulose hydrolysis process. ▶ In the reaction, short reaction time favors production of glucose and longer reaction time facilitates formation of HMF. 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. 13C 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 situ13C 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 [C4SO3Hmim]HSO4 at different temperatures (80–120°C) to obtain the important kinetic parameters such as apparent activation energies of consecutive reaction steps.