Prediction of the Thermodynamic Properties of Key Products and Intermediates from Biomass

The high-level G3MP2 computational chemistry method was used to predict the thermodynamic properties of a wide range of compounds relevant to the conversion of biomass-derived oxygenated feedstocks into fuels or chemical feedstocks. The starting compounds were glucose, 5-hydroxy-methyl furfural, sorbitol, levulinic acid, succinic acid, γ-valerolactone, and glycerol. The calculated G3MP2 gas-phase heats of formation were mostly within ±2 kcal/mol of the available experimental values. Heats of formation of the liquid were obtained from calculations of the boiling point combined with the rule of Pictet and Trouton using modified values for Δ S vap . The modified values for Δ S vap arise because of the presence of intermolecular hydrogen bonding, Δ S vap = 0.031 cal/(mol K) for carboxylic acids, 0.035 cal/(mol K) for dialcohols, and 0.040 cal/(mol K) for higher polyalcohols. The thermodynamics of a wide range of reactions were predicted. Reaction energies in the aqueous phase at 298 K were estimated from self-consistent reaction field calculations of the solvation energy using the COSMO parametrization. Most of the reactions were exothermic, and the reaction products were stabilized by aqueous solvation. Exceptions include dehydrogenation, decarbonylation, ring-opening, and dehydration reactions when only one mole of water is eliminated.