Fe2O3-V2O5掺杂Cr2O3催化间甲酚甲基化制2,3,6-三甲基苯酚

摘要

Metallic oxide doped Fe2O3-V2O5 catalysts, which were used in the methylation of w-cresol to 2, 3, 6-trimethylphenol, were prepared by the addition of CeO2, CaO, ZnO, ZrO2 or Cr2O3 to the Fe2O3-V2O5 catalyst. The results showed that Cr2O3 doping could improve the catalyst activity with the optimized ratio n(Fe) : n(V) : n(Cr) 100.0 : 1.0 : 0.5. The optimized catalyst preparation conditions were: calcination temperature 450 ℃, calcination time 4 h and 25%(w)NH3 , H2O as the precipitant. Under the appropriate reaction conditions of reaction temperature 330 ℃ and LHSV 0.53 h-1, the conversion of w-cresol and selectivity to 2, 3, 6-trimethylphenol could reach 99.2% and 94.6%, respectively. The reaction temperature is lower than that of Fe2O3-V2O5 catalyst.%为得到高效低温催化剂,在Fe2O3-V2O5复合氧化物催化剂中添加不同金属氧化物MaOb(MaOb=CeO2,CaO,ZnO,ZrO2,Cr2O3)对其进行改性,制得Fe2O3-V2O5-MaOb催化剂,并将其用于间甲酚甲基化制备2,3,6-三甲基苯酚的反应.实验结果表明,按n(Fe)∶n(V)∶n(Cr)=100.0∶1.0∶0.5的比例添加Cr2O3可有效改善Fe2O3-V2O5催化剂的活性,优化的Fe2O3-V2O5-Cr2O3催化剂制备条件为:焙烧温度450℃、焙烧时间4 h、沉淀剂为25％(w)氨水.采用优化条件下制备的Fe2O3-V2O5-Cr2O3催化剂进行间甲酚甲基化反应,适宜的反应条件为:反应温度330℃、进料液态空速0.53 h-1.在优化反应条件下,间甲酚转化率为99.2％,2,3,6-三甲基苯酚选择性为94.6％.