(624b) Rational Design of Mixed Solvent Environments for Acid-Catalyzed Biomass Conversion Reactions: A Combined Approach Using Experiments and Molecular Simulations
Here, we will present results for the Brønsted-acid-catalyzed reactions of ethyl tert-butyl ether, tert-butanol, levoglucosan, 1,2-propanediol, fructose, cellobiose, and xylitol in mixtures of water with [gamma]-valerolactone, tetrahydrofuran and 1,4-dioxane in varying compositions. We demonstrate how reactants containing more hydroxyl groups exhibit greater catalytic turnover rates for both dehydration and hydrolysis reactions as the water content of the mixed solvent environment decreases. We present classical molecular dynamics (MD) simulations to probe the nature of these solvent effects by quantifying the extent of water enrichment in the local domain about the reactants, and the hydrogen bonding strength between water molecules and the reactants, both as a function of solvent composition. By correlating the experimental reaction kinetics data with the behavior of these simulation-derived observables, we develop a model that accurately predicts the rates of all seven acid-catalyzed reactions as a function of the composition of the liquid phase. The development of this modeling tool represents an important step toward a general understanding of solvent effects in acid-catalyzed biomass conversion processes, and toward the rational design of mixed solvent environments for new liquid phase processes.