Ag-Fe_2O_3-V_2O_5/TiO_2催化剂制备及其甲基吡啶催化氧化脱甲基性能

针对甲基吡啶氧化脱甲基反应,以TiO_2为载体经浸渍法制备Ag-Fe_2O_3-V_2O_5/TiO_2催化剂,结合结构表征和催化剂性能评价,考察制备条件对其催化甲基吡啶氧化脱甲基性能的影响。结果表明,通过Fe_2O_3改性可以提高Ag-V_2O_5/TiO_2催化剂对3-甲基吡啶氧化脱甲基化反应的催化性能,其作用主要是抑制V_2O_5团聚,促进V物种的分散。同时,锐钛矿相TiO_2载体表面B酸中心有利于催化3-甲基吡啶脱甲基,提高产物吡啶选择性。经实验优化,Ag-Fe_2O_3-V_2O_5/TiO_2催化剂适宜制备条件为:焙烧温度450℃、焙烧时间4 h、V_2O_5和Ag的负载质量分数分别为15%和1.5%、Fe与V物质的量比1∶2。在优化条件下,吡啶收率与选择性最高可达到62.97%和78.75%。

Preparation and catalytic performance of Ag-Fe2O3-V2O5/TiO2 on the oxidation demethylation of methylpyridine

For the oxidation demethylation of methylpyridines,Ag-Fe₂O₃-V₂O₅/TiO₂ catalyst was prepared by impregnation method with as TiO₂ carrier.Effects of its preparation conditions on the catalytic performances were investigated by structural characterizations and catalytic experiments.The results indicated that the modification of Fe₂O₃ can significantly improve the catalytic activity and selectivity of V-Ag/TiO₂ for the oxidation demethylation of 3-picoline.The addition of Fe₂O₃ mainly depressed the agglomeration of V₂O₅,so that V species were better dispersed on the surface of TiO₂.The B acid site on the surface of anatase TiO₂ is favor for the demethylation of 3-picoline to obtain high selectivity of pyridine.The optimized preparation conditions of Ag-Fe₂O₃-V₂O₅/TiO₂ catalyst are calcination temperature 450 ℃ and calcination time 4 hours.The adding amount of V₂O5and Ag are 15wt% and 1.5wt%,respectively.The molar ratio of Fe/V is 1:2.Under optimization reaction conditions,the highest yield and selectivity of pyridine arrived at 62.97% and 78.75%,respectively.