Enhancing aldol condensation with coupling oxygen storage materials and VPO catalysts: Impact of oxygen, kinetics and mechanism

Abstract

Supported vanadium-phosphorus oxide (VPO) bilayer composite catalysts were prepared using oxygen storage compounds (CeO₂, ZrO₂, TiO₂, and other forms) as catalyst supports, and applied to the aldol condensation of acetic acid and formaldehyde to produce acrylic acid. The active oxygen species on the crystal surface of rod-shaped CeO₂ (VPO/CeO₂-r) catalyst loaded with VPO effectively suppress catalyst carbon deposition and deactivation. CeO₂-r had good oxygen storage and oxygen transfer capabilities. The surface microstructure, catalytic performance, and oxygen vacancies were characterized by SEM, XRD, FI-IR, BET, TG, and EPR methods. The influence of catalytic support and reaction conditions was interrelated in an oxygen-containing atmosphere. RSM experimental design was performed and fitted to the kinetic. Under the optimal reaction conditions, using 40 % VPO/CeO₂-r, O₂ flow rate of 6 mL/min, the yield of acrylic acid was 72.6 %, and there was no carbon deposition or deactivation after the operation cycle.