SO_4^(2-)/TiO_2-HNbMoO_6的制备及其对甲苯硝化反应的催化性能

Preparation of SO_4^(2-)/TiO_2-HNbMoO_6 and Its Catalytic Performance for Toluene Nitration

采用插层-柱撑和浸渍的方法制备了新型的固体酸催化剂SO_4^(2-)/TiO_2-HNbMoO_6,并用XRD、LRS、TG-DSC和NH3-TPD等手段对催化剂进行表征。结果表明,复合物SO_4^(2-)/TiO_2-HNbMoO_6保存了前驱体的层状结构且层间距有所提高,其热稳定性和酸性也有明显增强。当反应温度为40℃,反应时间为2.5h时,以CCl4为溶剂,以质量分数为95%的硝酸和醋酸酐混合物为硝化剂,以经500℃焙烧3h后的SO_4^(2-)/TiO_2-HNbMoO_6作为催化剂,甲苯硝化产物中异构体的对邻比达1.54,较HNbMoO_6的1.28明显提高,甲苯转化率达100%。

A novel solid acid catalyst SO42 - /TiO2‐HNbMoO6 was prepared by the methods of intercalation‐pillared and impregnation .It was characterized by means of XRD ,LRS ,TG‐DSC and NH3‐TPD .The results showed that the layered structure of the precursor was maintained after composite and the layer spacing was increased ,the thermal stability and acidity were also significantly enhanced .The nitration of toluene was carried out with CCl4 as solvent ,the mixture of acetic anhydride and 95% nitric acid as nitrating reagent ,and SO42 - /TiO2‐HNbMoO6 calcinated at 500℃ for 3 h as catalyst for 2 .5 h at 40℃ .And the conversion rate of toluene was 100% and p/o ratio was 1 .54 which was significantly improved than that of HNbMoO6 (1 .28) .