Abstract：The crystalline phase composition, valence states of vanadium (V), and acidic/basic sites of vanadium phosphorus oxide (VPO) catalysts play critical roles in their catalytic performance. While existing literature reported high activity of VPO catalysts in aldol condensation reactions, challenges such as catalytic instability and limited operational lifespan persist. To address the deactivation issues of VPO catalysts during the aldol condensation of acetic acid and formaldehyde, this study employed characterization techniques including X-ray diffraction (XRD), scanning electron microscope (SEM), and X-ray photoelectron spectroscopy (XPS) to analyze changes in crystalline structure, surface morphology, and elemental valence states before and after reactions. Combined with fixed-bed reactor evaluation, and long-term stability assessments, the effects of oxygen concentration on catalytic activity, selectivity, and stability were systematically investigated. Results indicated that oxygen concentration significantly influenced deactivation rates and product distribution. Under oxygen-free conditions, severe carbon deposition caused rapid activity decline (formaldehyde conversion rate decreased from 95.4% to 80.5% within 400 min), whereas introducing oxygen effectively mitigated carbon deposition, delayed crystalline phase collapse, and optimized the V5+/V4+ ratio and acidic/basic site distribution, achieving 92.4% acrylic acid selectivity. Furthermore, catalyst regeneration and long-term aldol condensation evaluations confirmed that a 10% oxygen concentration enhanced operational stability, providing a feasible strategy for industrial continuous production of VPO catalysts in aldol condensation reactions.
ZHANG Yuchen,ZHANG Lingling,TONG Mingliang et al. Study on Deactivation and Regeneration of Aldol Condensation Catalyzed by VPO Catalyst[J]. Chemical Reaction Engineering and Technology, 2025, 41(5): 558-566.
