The kinetics of gas-phase furfural partial oxidation to maleic anhydride (MA) was studied over bulk vanadium–phosphorus-based catalysts obtained by aqueous (VPAq) and organic (VPOr) methods and compared to a supported V₂O₅/Al₂O₃ catalyst. The solids were characterized by N₂ adsorption–desorption, XRD and UV-vis DRS. Results showed a higher specific surface area on VPOr compared with VPAq materials, with a well-defined (VO)₂P₂O₇ crystalline structure. UV-vis analysis showed mainly V(V) on VPAq and an intermediate state between V(IV) and V(V) on VPOr. A detailed kinetic study demonstrated that furfural can be oxidized to MA or CO_x through parallel paths. At high oxygen partial pressures MA oxidation is inhibited on VPO catalysts but favored on V₂O₅/Al₂O₃. A Langmuir–Hinshelwood kinetic model with negligible site occupancy fits the experimental data with a 16% mean error. It also shows a higher apparent activation energy for furfural partial oxidation than for complete oxidation, highlighting the favored selectivity to maleic anhydride at higher temperatures on VPO catalysts.

中文翻译：

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用于糠醛氧化成马来酸酐的本体和负载型钒基催化剂的动力学和结构理解

在通过水法 (VPAq) 和有机法 (VPOr) 获得的本体钒磷基催化剂上研究了气相糠醛部分氧化成马来酸酐 (MA) 的动力学，并与负载型 V ₂ O ₅ /Al ₂ O 进行了比较。₃催化剂。通过N ₂吸附-解吸、XRD 和UV-vis DRS对固体进行表征。结果表明，与 VPAq 材料相比，VPOr 具有更高的比表面积，具有明确的 (VO) ₂ P ₂ O ₇晶体结构。UV-vis 分析主要显示VPAq 上的V( V ) 和 V( IV ) 和 V( V )之间的中间态) 在 VPOr 上。详细的动力学研究表明，糠醛可以通过平行路径氧化为 MA 或 CO _x。在高氧分压下，MA 氧化在 VPO 催化剂上受到抑制，但对 V ₂ O ₅ /Al ₂ O ₃有利。场地占用率可忽略不计的 Langmuir-Hinshelwood 动力学模型与实验数据吻合，平均误差为 16%。它还显示出糠醛部分氧化比完全氧化更高的表观活化能，突出了 VPO 催化剂在较高温度下对马来酸酐的有利选择性。