Oscillatory Behavior during Methanol Oxidation on Mo–Ca–O/SiO2Catalyst

Abstract

The authors have recently reported on the observation of an oscillatory behavior during mild methanol oxidation on a silica-supported molybdenum catalyst (1). This unusual behavior in mild oxidation on oxide catalysts is nevertheless well known for CO total oxidation on platinum or palladium catalysts (2-5). The oscillatory behavior appears as a periodic or nonperiodic (chaotic) variation in the reaction rate and selectivities, although the external conditions of the reaction (oven reactor temperature, flow rate, and feed composition) are constant. This phenomenon was extensively studied for total oxidation reactions occurring on metallic catalysts (5) and comparatively, only a few number of examples of mild oxidation reaction on oxide catalysts are reported in the literature (6-9). Nevertheless, the diversity of the catalytic reactions showing an oscillatory behavior suggests that this phenomena is rather common in the complex system formed by catalyst, products, and reactants. The authors here on the study of an oscillatory behavior observed during methanol oxidation on a calcium molybdate catalyst supported on silica. 21 refs., 7 figs., 4 tabs.