Preparation Of Bifunctional Oxide Catalyst And Study On Catalytic Performance Of Methanol

As the coal chemical and petrochemical products, methanol has important applications in chemical production. but this year, due to the excess production of methanol, Therefore, it is of great significance to use methanol to prepare downstream high value-added chemicals. Among them,the selective oxidation of methanol can be used to prepare a series of chemical products with industrial application value. As a downstream product of methanol oxidation, methyl formate has important industrial value. It can be used not only as an intermediate for drug production and organic synthesis, but also for the productions of multi carbon molecular hydrocarbons. The traditional method of preparing methyl formate requires a multi-step reaction process, and by-products are more, which is unfavorable to the separation at a later stage. Therefore, it is of great economic significance to convert methanol into high value-added methyl formate by using bifunctional catalysts. Due to its unique advantages, the synthesis of methyl formate by one-step oxidation of methanol has attracted extensive attention in academia and industry. Although the production of methyl formate by selective oxidation of methanol is far from mature in industrial technology. However, the method can be used to prepare methyl formate directly, and it is economical and efficient, the design and preparation of bifunctional catalyst also has important significance.In this paper, V2O5 is supported on the surface of SiO2, γ-Al2O3, ZrO2 and TiO2 by incipient-wetness impregnation method. From the evaluation of the performance of the catalyst for the oxidation of methanol, it is found that the performance of the catalyst is highest when TiO2 is used as the carrier.Then, the conditions of V2O5 loading and calcination temperature in the preparation of catalysts are studied, the preparation conditions of catalysts are optimized and modified, and the structure of the catalysts are characterized by XRD, FTIR, TPR, TPD and XPS, and the performance of catalysts are evaluated by the fixed bed reactor.TiO2 is used as the carrier to prepare a series of catalysts with V2O5 loading of 1wt%, 5wt%, 10wt%, 15wt% and 20wt%, respectively. The results show that 10wt%V2O5/TiO2 catalyst that the calcination temperature is 500 ℃ has the highest performance for methanol oxidation. Then, it is indicated when the catalyst loading is 0.10 g, the flow rate of oxygen is 20 ml/min, nitrogen flow rate is 20 ml/min, the reaction conditions is 190 ℃with optimizing the reaction conditions, conversion of methanol can reach 44.94%. at the same time, methyl formate selectivity and yield are 61.01%and 27.42%. Finally, the stability of the 10wt%V2O5/TiO2 catalyst in catalytic reaction is tested. After 80 hours of continuous use, conversion of methanol and the selectivity of methyl formate decreased slightly. which indicated that the catalyst for methanol oxidation reaction have a certain stability.After that, the effect of different additives on the modification of the catalyst is studied. The addition of MgO, La2O3, CeO2, CoO, CuO, ZrO2,Y2O3 and MoO3 to the TiO2 support is studied. And a series of modified 10wt%V2O5/TiO2 catalysts are prepared. The results show that the ZrO2 additive has the best improvement on the performance of the catalyst. And then the preparation conditions of TiO2-ZrO2 composite support are optimized, when the additive amount of ZrO2 is 10wt%, the catalysts with composite carrier are prepared at 500 ℃ by incipient-wetness impregnation method. The supported catalyst have the highest performance for methanol oxidation reaction.The conversion of methanol can reach 50.34%, and the selectivity and yield of methyl formate is 61.77% and 31.10%.