枸橼酸法制备纯晶相Mg_3（VO_4）_2及其环己烷氧化脱氢反应性能

摘要

采用枸橼酸法制备纯晶相Mg3 VO4 2,考察不同制备条件对催化剂微观形貌、物理性质以及环己烷氧化脱氢反应制取环己烯的影响.实验结果表明,当枸橼酸加入量与溶液中金属离子量物质的量比为1.2∶1,起始溶液pH值为4.8,焙烧温度为550°C及焙烧时间为6h时,制备的Mg3 VO4 2催化剂具有高度均一性、晶粒尺寸大小为110 nm且具有较好的环己烷氧化脱氢反应催化性能.在反应温度450℃、烃氧比为2∶1及环己烷进料量为0.107 mol/h的条件下,环己烯产率为6.4%.%Citric acid method was proposed to prepare Mg3 VO4 2 which was used as an active catalyst for the oxidative dehydrogenation of cyclohexane to cyclohexene.Effects of the preparation conditions were investigated in details.The experimental results showed that Mg3 VO4 2 catalyst calcined at 550℃ for 6 h with a molar ratio of citric acid∶metal ion = 1.2∶1 and initial pH = 4.8,exhibited the best catalytic performance with an excellent thermal stability.The yield of cyclohexene was 6.4% under the temperature of 450 °C,the molar ratio of cyclohexane to oxygen of 2∶1 and the flow of cyclohexane of 0.107 mol/h.