Cellulosic conversion in ionic liquids (ILs): Effects of H2O/cellulose molar ratios, temperatures, times, and different ILs on the production of monosaccharides and 5-hydroxymethylfurfural (HMF)

The effects of several critical factors including H2O/cellulose molar ratios, dissolution temperatures (Tdis), dissolution times (tdis), reaction temperatures (Trxn), reaction times (trxn), and types of ionic liquids (IL) were investigated for cellulosic conversion. We optimized the reaction conditions as: H2O/cellulose = 10/1, Tdis = 120 °C, tdis = 0.5 h, Trxn = 120 °C, trxn = 3 h for 1-ethyl-3-methylimidazolium chloride ([EMIM]Cl)-based system, and the maximum yield of 5-hydroxymethylfurfural (HMF) up to 21% could be achieved without adding extra catalysts. Another pyridinium-typed IL, [Epyr]Cl, was also used in the cellulosic conversion, and the results showed a high selectivity toward monosaccharides. The information obtained in this study will benefit many biofuel-related applications.

Graphical abstractFigure optionsDownload full-size imageDownload high-quality image (107 K)Download as PowerPoint slideHighlights► The optimal water/cellulose molar ratio is 10/1. ► The optimal dissolution temperature and time are 120 °C and 0.5 h, respectively. ► The optimal reaction temperature and time are 120 °C and 3 h, respectively. ► The maximum HMF and monosaccharides yield are 21% and 24.9%, respectively.