Dissolution of Cotton Cellulose with Ionic Liquids 1-Butyl-3-Methylimidazolium Chloride and 1-Allyl-3-Methylimidazolium Chloride to Prepare Reducing Sugar

Abstract

The synthesized ionic liquids, 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) and 1-allyl-3-methylimidazolium chloride ([AMIM]Cl) were used to treat cotton cellulose in order to improve the efficiency of enzymatic hydrolysis. The results showed that the reducing sugar concentration from regenerated cotton cellulose was improved to 41.47 and 41.99 g/L, respectively, when pretreated by [BMIM]Cl and [AMIM]Cl. However it was only 18.14 g/L for untreated cotton cellulose. It was found that dissolving capacity of [AMIM]Cl was better than [BMIM]Cl at the same temperature. Their optimal dissolve temperatures were 180°C and 170°C, respectively, and maximum solubility of cotton cellulose was both 19%. Scanning electron microscopy (SEM) images revealed that the surfaces of regenerated cellulose treated by ionic liquids became rough and the dense regular structure of the original was spoiled. X-ray diffractometer (XRD) showed that the crystalline size of regenerated cotton cellulose was significantly reduced, indicating that the crystallinity of cellulose decreased due to the effects of ionic liquids.