助剂钾对V2O5-Ag2O催化氧化甲苯制苯甲醛的研究

制备了 V2O5- Ag2O- K2O/Al2O3- MgO和 V2O5- Ag2O- K2O/Al2O3- USY用于甲苯气相催化氧化制苯甲醛,研究助剂 K对催化剂作用的影响,研究表明 K有助于降低亲电子氧( O-、O2-)的含量,而亲电子氧是甲苯过度氧化的氧源,同时也阻止甲苯上甲基的断裂;提高甲苯氧化的选择性,阻止甲苯上甲基的断裂,使苯的生成减少. K有助于亲核氧( O2-)的生成,加快催化氧化过程. X衍射图谱分析表明,过量 K易形成无活性的 KVO3,不利于催化过程.

Study of Potassium Doping on the Properties of V2O5- Ag2O Catalysts in Gas Phase Catalytic Oxidation of Toluene to Benzaldehyde

V_2O_5-Ag_2O-K_2O/Al_2O_3-MgO and V_2O_5-Ag_2O-K_2O/Al_2O_3-USY are prepared to be used in gaseous phase catalyticoxidation of toluene to benzaldehyde;the product during toluene oxidation by the oxygen present in the catalyst is compared for K-dopedand non-doped samples.Studies have shown:K contributes to reduce the surface concentration of electrophilic oxygen(O~-,O~2-),which is usually responsible for the deep oxidation,prevents the fracture of the methyl on the toluene,reduces the benzene formulation;a higher concentration of nucleophilic oxygen(O~2-),responsible for the partial oxidation of toluene;raises selectivity for benzaldehyde,but at a high concentration of potassium,the active vanadium species would transform into inactive KVO_3.