A microkinetic model of the methanol oxidation over silver

A simple microkinetic model for the oxidation of methanol on silver based on surface science studies at UHV and low temperatures has been formulated. The reaction mechanism is a simple Langmuir–Hinshelwood mechanism, with one type of active oxygen and one route to formaldehyde and carbon dioxide, respectively. The model explains observed reaction orders, selectivity, apparent activation enthalpies and the choice of industrial reaction conditions. More interesting the model disproves the notion that the mechanism deduced from surface science in UHV cannot be responsible for formaldehyde synthesis at industrial steady-state conditions. The present work therefore seriously questions the prevailing models of formaldehyde synthesis in the literature. One of the reasons for this controversy is that many of the models in the literature are derived from transient experiments exhibiting dynamic effects that are not present at steady state under industrial conditions.