Reaction Pathways in Acrolein Oxidation over a Mixed‐Oxide Catalyst

Abstract

A reaction network detailing the mechanistic origins of 17 C1−C7 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 C1−C7 organics formed as byproducts, acrylic acid 13C isotopic tracer experiments, and probe molecule reactions. C1 and C2 products form via C−C bond scission of either the single or double C−C bond in acrolein and acrylic acid. C4−C7 products form by addition of one or two acrolein or acrylic acid molecules to a C2 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.

Selective Oxidation of Methacrolein over Crystalline Mo3VOx Catalysts and Comparison of Their Catalytic Properties with Heteropoly Acid Catalysts

“…In the case of Orth-MoVO, methacrylate is one of the reaction intermediates during MAA formation, as suggested by in situ FT-IR measurements (Figure ). This is similar to ACR oxidation over Mo–V metal oxides, where acrylate is the reaction intermediate forming AA. ,,− Recently, Vogel et al reported that ACR oxidation over Mo–V metal oxide catalysts proceeds according to the following mechanism: (1) adsorption of ACR forming a surface acetal, (2) abstraction of C–H from the surface acetal to form a surface acrylate, (3) hydrolysis of the surface acrylate by a water molecule to form AA, leaving an oxygen vacancy, and (4) replenishment of the oxygen vacancy either directly by gaseous oxygen or indirectly by the bulk lattice oxygen . Considering this reaction mechanism and the results obtained above, it was proposed that MCR oxidation over Orth-MoVO proceeds as follows: (1) adsorption of MCR at the heptagonal channel site, (2) insertion of lattice oxygen into the adsorbed MCR to form a surface acetal, (3) abstraction of the acetal C–H by lattice oxygen to form methacrylate, (4) hydrolysis of methacrylate by a water molecule to form MAA with removal of the lattice oxygen as water, and (5) replenishment of the consumed lattice oxygen either by the direct oxidation with molecular oxygen or by the diffusion of bulk lattice oxygen.…”

Active learning of chemical reaction networksviaprobabilistic graphical models and Boolean reaction circuits

“…11,12 The research of Bhan and coworkers has especially highlighted the importance of identifying the reaction network to construct reliable kinetic models. [13][14][15][16][17] They effectively confirmed the occurring reactions by applying Wojciechowski's criteria to first-rank delplots 18,19 and conducting experiments with product, isotopic labeling, and probe molecule co-feeds. 20 Various experimental data collection and analysis techniques exist to enable kinetic model development; design of experiments (DOE) can propose optimal experiments to minimize the number of measurements.…”

Catalytic Activation of Polyethylene Model Compounds Over Metal‐Exchanged Beta Zeolites

“…Product selectivity does not systematically vary with time on stream during reactions, so selectivities shown here are averaged over entire hexadecane decomposition reactions. Klein and coworkers developed a formalism for analyzing these plots, [33,34] known as first-rank delplots, to determine the role of products in reaction networks; this analysis has been applied to many systems including oxidation [35][36][37] and hydrogenation [38] of organic molecules. In short, if the selectivity of a product extrapolated to zero conversion is finite on a first-rank delplot, then the product is primary, meaning that it is formed directly from the reactant.…”