N-methyl-2-pyrrolidonium-based Bronsted-Lewis acidic ionic liquids as catalysts for the hydrolysis of cellulose

• Published in: Science China. Chemistry 2016-05, Vol.59 (5), p.564-570
• Main Authors: Zhao, Zheng, Li, Na, Bhutto, Abdul Waheed, Abdeltawab, Ahmed A., Al-Deyab, Salem S., Liu, Guangqing, Chen, Xiaochun, Yu, Guangren
• Format: Article
• Language: English
• Subjects: Catalysts; Cellulose; Charge transfer; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Cotton; Crystalline cellulose; Density functional theory; FeCl3; Ferric chloride; Hydrolysis; Ionic liquids; Iron; Lewis酸性; Metal chlorides; Sugar; 催化性能; 密度泛函理论; 微晶纤维素; 水解催化剂; 酸性离子液体; 金属氯化物
• ISSN: 1674-7291; 1869-1870
• DOI: 10.1007/s11426-016-5592-1

We experimentally studied the catalytic performances of a series of Brrnsted-Lewis acidic N-methyl-2-pyrrolidonium metal chlorides （[Hnmp]Cl/MClx, where M=Fe, Zn, A1, or Cu） for the hydrolysis of microcrystalline cellulose （MCC） and cotton to produce reducing sugar. A variety of factors, such as temperature, time, ionic liquid （IL） species, IL dosage, and the concentra- tion of the metal chloride were investigated. [Hnmp]Cl/FeCl3 presented the best hydrolysis performance, affording a 98.8% yield of total reducing sugar from MCC （1 h, 100 ℃, 0.1 g MCC, 0.2 g acidic IL, 2.0 g [Bmim]Cl as solvent）, which is better than or comparable to results previously obtained with other -SO3H functionalized acidic ILs. The hydrolysis performances of [Hnmp]Cl/MClx were rationalized using density functional theory calculations, which indicated that interactions between the metal chlorides and the cellulose, including charge-transfer interactions are important in the hydrolysis of cellulose and degra- dation of glucose. This work shows that Bronsted-Lewis acidic ILs are potential catalysts for the hydrolysis of cellulose to produce sugar.