Fe-Mo对二甲苯选择氧化催化剂的制备及其性能

以Fe(NO₃)₃和(NH₄)₆MoO₂₄为原料，采用溶胶-凝胶法制备了不同n(Fe)∶n(Mo)的催化剂，考察了该催化剂对对二甲苯催化氧化合成对苯二甲醛的催化性能。并应用X射线衍射、傅立叶变换红外光谱、紫外漫反射和热分析对催化剂进行了表征。结果表明，Fe对MoO₃改性能明显改善催化剂的活性，提高对苯二甲醛收率，原因是由于Fe₂(MoO₄)₃的生成。当n(Fe)∶n(Mo)=1∶3时,催化剂活性最佳，此时对二甲苯转化率为66.8%，对苯二甲醛选择性和收率分别为37.2%和24.8%。XRD、FT-IR和DRS结果表明，当n(Fe)∶n(Mo)=1∶3时,催化剂中有适量MoO₃存在，其催化活性最好，该催化剂能在高温维持较好的活性稳定性。

Preparation of Fe-Mo catalysts for selective oxidation of p-xylene and its catalytic behaviors

Catalysts with different Fe/Mo molar ratio were prepared by sol-gel method, with the precursor being obtained from Fe(NO₃)₃ and (NH₄)₆MoO₂₄ in citric acid, characterized by XRD, FT-IR, DRS and DSC. Catalytic behaviors of the catalysts for selective oxidation of p-xylene to terephthalaldehyde(TPAL) were investigated. The results showed that modification of MoO₃ by Fe enhanced activity of the catalyst and yield of TPAL due to formation of Fe₂(MoO₄)₃, with p-xylene conversion of 66.8%, selectivity to TPAL of 37.2% and TPAL yield of 24.8% at optimum Fe/Mo molar ratio of 1∶3. XRD, FT-IR and DRS results showed that there existed appropriate amount of MoO₃ at Fe/Mo molar ratio of 1∶3, leading to optimum catalytic activity and high activity stability at high temperature.