Reaction Pathways in Acrolein Oxidation over a Mixed-Oxide Catalyst

A reaction network detailing the mechanistic origins of 17 C-1-C-7 byproducts in acrolein oxidation over a vanadium molybdate mixed oxide catalyst doped with antimony and copper is proposed based on measurements of acrolein oxidation rates with co-feeds of C-1-C-7 organics formed as byproducts, acrylic acid C-13 isotopic tracer experiments, and probe molecule reactions. C-1 and C-2 products form via C-C bond scission of either the single or double C-C bond in acrolein and acrylic acid. C-4-C-7 products form by addition of one or two acrolein or acrylic acid molecules to a C-2 surface species coupled with decarbonylation or decarboxylation events. Two-carbon ethyl and vinyl surface species and three-carbon acrolein-derived surface species are involved in all pathways that lead to byproduct formation; controlling the relative abundance and reactivity of such intermediates is integral to prescribing process conditions and material compositions for selective oxidation of acrolein.