Selective oxidation of propane to acrylic acid: a critical review

The direct oxidation of propane to acrylic acid (AA) has emerged as a promising route for AA production, leveraging the abundant availability of propane as a feedstock. Among various catalysts, mixed metal oxide (MMO) catalysts, particularly those containing vanadium (V), tellurium (Te), and niobium (Nb), have garnered extensive attention due to their exceptional capabilities for C–H bond activation and high selectivity toward AA. This review systematically summarizes recent advances in understanding the structural and phase composition of MMO catalysts, and elucidates the roles of V, Te, and Nb as active sites in propane activation, intermediate stabilization, and selective oxidation. Furthermore, strategic approaches to enhance catalytic performance are critically discussed. These include elemental doping or substitution (e.g., with alkali/alkaline earth metals, rare earth elements, Mn, Bi, W, Cu, Co, Zr, Cr, and P) and the assembly of metal oxides (such as TiO₂ and SiO₂). In parallel, the optimization of reaction parameters – such as feed composition, temperature, and contact time – is analyzed to establish correlations between process conditions and catalytic efficiency. Beyond catalyst design and reaction engineering, innovative reactor configurations are explored as a means to improve overall process performance. These configurations include modifications of conventional fixed-bed reactors, as well as the exploitation of cyclic/pulse and fluidized-bed reactors.