Mechanistic Insights into Solution-Phase Oxidative Esterification of Primary Alcohols on Pd(111) from First-Principles Microkinetic Modeling

We present an ab initio microkinetic model for the oxidative esterification of 1-propanol to methyl propionate over Pd(111). The model fully accounts for solvation of solution-phase species and added catalytic base and provides key insights into the factors that limit the activity of unpromoted Pd aerobic oxidation catalysts. In particular, we find that the activity is limited by the large steady-state surface H coverage, which destabilizes other adsorbed intermediates via lateral interactions, and substantial barriers governing the formation of O–H bonds, which is required for the reduction of O2 and removal of H byproducts from the catalyst surface.