Cu/SiO_2催化剂的制备及在环己醇脱氢制环己酮反应中的催化性能

Preparation of Cu/SiO_2 catalyst and catalytic performance study on dehydration of cyclohexanol to cyclohexanone

采用共沉淀法制备了不同铜/硅物质的量比的Cu/SiO2催化剂,结果表明:在n(Cu)∶n(Si)=1∶2时,DH-0.5-400催化剂在环己醇脱氢制环己酮的反应中表现出优异的催化活性。考察了不同焙烧温度对环己醇脱氢制环己酮的影响。结果表明:焙烧温度400℃时,制备的DH-0.5-400催化剂上的环己酮得率为52.9%,高于其他催化剂。采用XRD和BET对催化剂进行了表征,根据结果,在催化剂中氧化铜是以均匀、高分散的微小纳米粒子或以簇的形式存在,结果增加了与反应物的接触机会,致使DH-0.5-400催化剂显示出高的催化性能和环己酮选择性。

The series of Cu/SiO2 catalyst with the different molar ratio of Cu/Si are prepared by the co-precipitation method. When the molar ratio of copper to silica is 1 ： 2, as-prepared DH-0.5-400 shows the excellent catalytic performance in the dehydrogenation of cyclohexanol to cyclohexanone based on the activity results. The effect of different calcination temperature on the dehydrogenation of cyclohexanol to cyelohexanone is investigated and the result shows that using DH-0.5-400 catalyst calcined at 673 K , the yield of eyclo- hexanone is 52.9% which higher than that of other catalysts. The catalysts are characterized by means of XRD and BET. The results indicate that the statuses of copper oxide in the DH-0.5-400 catalyst are uniform, highly dispersive in the silica, increasing the contact chances between active species and cyclohexanol. Therefore, DH-0.5-400 catalyst shows better catalytic activity and higher selectivity of cyclohexanone.