(509i) Two-Phase Kinetics of Ionic Liquid-Mediated Catalytic Conversion of Lignocelluloses to Biofuel Precursors: Experimental and Modeling Analyses

Here, we perform a coupled experimental-modeling study to quantify the effects of water addition on the two-phase kinetics of batch conversion of lignocellulose to biofuel precursors such as glucose, hydroxymethylfurfural (HMF), levulinic acid (LA), and formic acid (FA) using alkali metal (CuCl₂) catalysts in ionic liquid ([Bmim]Cl) medium. The primary objectives of this study are to (i) quantify the effect of water addition on reaction kinetics, (ii) develop a two-phase kinetic model based on the published reaction scheme and validate its solution with our experimental data, (iii) determine the kinetic parameters in the model by fitting our simulations to our experimental data. This work uses Sunn hemp fibre - a non-food lignocellulosic energy crop, containing cellulose (75.6%), hemicelluloses (10.05%), and lignin (10.32%) - for catalytic hydrolysis for second generation biofuel production. We experimentally demonstrate how to employ ionic liquid-mediated autocatalytic pathways to rapidly rupture the glycosidic bonds of cellulose in oil-bath reactors to produce biofuel precursors. The experiments are performed in 15 ml glass vials heated in a temperature-controlled silicon oil-bath maintained at 160°C, where the contents are mixed using a magnetic stirrer at 500 rpm. The cross-catalyst water is added at rates varying from 45 to 75 µl/gm/h. The samples are collected every half-hour for 24 h of reaction time, and the concentrations of the biofuel precursors, such as glucose, HMF, LA, and FA, are measured. The maximum yields of glucose and HMF are obtained as 59.9% and 2.8%, respectively at 5 h, while that of LA and FA are 18.4% and 7.3%, respectively, at 24 h. Our two-phase kinetic model is simulated using MATLAB, and the results are fitted with our experimental data of 45 µl/gm/h to determine the kinetic constants. Our two-phase model is then validated using our experimental data for various other higher water addition rates.