(196a) Utilizing Solution-Based Calorimetric Methods to Understand Solution Thermodynamics and Catalysis at Solid-Liquid Interfaces Relevant to Biomass Conversion

The low volatility of biomass-derived compounds and the omnipresence of water in biomass feed streams typically requires that their conversion/upgrading by catalytic routes be conducted at “buried” solid-liquid interfaces.  Under these circumstances, the role of solvent becomes critical since it constitutes the majority species in solution and on the catalyst surface.  The interactions between solute and solvent in solution (i.e., excess solution thermodynamic properties) and at a solvated interface are complicated but must be accounted for when measuring chemical kinetics or determining reaction mechanisms.  In this tutorial talk, we will review methods, primarily focused on calorimetry, and other techniques capable of characterizing solid-liquid interfaces that provide complementary information will be included.  Following a brief introduction to solution-phase calorimetry, I will provide examples from our own research using calorimetry to quantitatively assess water tolerance (or conversely water inhibition) in heterogeneous organocatalysts using a simple esterification reaction as a reactivity test and to measure solution thermodynamics in order to more rigorously describe adsorption isotherm data.  From our participation in collaborative research, I will demonstrate how solvent effects can be accounted for quantitatively for catalytic reactions involving both supported metal and homogeneous Brönsted acid catalysts using calorimetry and complementary techniques, including theoretical calculations.