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

Preparation and catalytic performance of Ag-Fe_2O_3-V_2O_5/TiO_2 on the oxidation demethylation of methylpyridine

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%。

For the oxidation demethylation of methylpyridines,Ag-Fe 2O3-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 Fe 2 O 3 can significantly improve the catalytic activity and selectivity of V-Ag/TiO 2 for the oxidation demethylation of 3-picoline.The addition of Fe 2 O 3 mainly depressed the agglomeration of V 2 O 5,so that V species were better dispersed on the surface of TiO 2.The B acid site on the surface of anatase TiO 2 is favor for the demethylation of 3-picoline to obtain high selectivity of pyridine.The optimized preparation conditions of Ag-Fe 2 O 3-V 2 O 5/TiO 2 catalyst are calcination temperature 450℃and calcination time 4 hours.The adding amount of V 2 O 5 and 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.