仲丁醇脱氢制甲乙酮的Cu-ZnO催化剂

Research of Cu-ZnO catalysts for sec-butanol dehydrogenation to methyl ethyl ketone

采用共沉淀法和机械混合法制备了铜锌催化剂,并利用TPR、XRD和N2O吸附分解催化剂表征手段分析了铜锌催化剂中ZnO和Cu在仲丁醇(sec-butanol,SBA)脱氢反应中的作用。研究表明,Cu0是SBA脱氢的活性中心,ZnO具有分散铜物种和抗烧结能力。ZnO能够有效分散铜物种和阻止Cu0烧结的原因是在催化剂制备过程中形成了(CuZn)x(OH)y(CO3)z(x=1,5;y=2,6,z=1,2)前体,经焙烧形成了高分散的CuO-ZnO固溶体。同时,通过SBA催化脱氢反应测试筛选了适宜的Cu/Zn摩尔比,当Cu/Zn为1∶1时,表现出良好的反应活性,常压、240℃下质量空速为17.5 h 1时,该催化剂对SBA转化率达到80.54%,甲乙酮(methyl ethyl ketone,MEK)收率达到76.04%。铜锌催化剂的脱氢活性与Cu0比表面积不呈线性关系,SBA脱氢反应是一结构敏感型反应。

Copper-zinc catalysts prepared by co-precipitation and physical mixing were characterized by TPR, XRD and N20 adsorption-decomposition techniques to analyze the roles of ZnO and Cu in the dehydrogenation of sec-butanol （SBA）. The studies suggested that Cu~ were active sites and ZnO was provided with the properties of dispersion and anti-sintering of Cu species. ZnO could effectively disperse Cu species and prevent Cu^3＋ from sintering because （CuZn）x（OH）y（CO3）z（x=1,5; y=2,6; z=1,2） precursor was formed in catalyst preparation and highly dispersed CuO-ZnO solid solution was shaped after calcination. Optimum Cu/Zn molar ratio was also studied for the dehydrogenation tests of SBA. Cu/Zn molar ratio at 1 ： 1 exhibited excellent reactivity. Conversion of SBA and yield of methyl ethyl ketone （MEK） reached 80.54% and 76.04%, respectively, under atmospheric pressure, at reaction temperature 240 ℃ and weight space velocity 17.5 h-1. The dehydrogenation activity of copper-zinc catalyst was not in linear relationship with Cu^0 surface area, indicating that dehydrogenation of SBA could be a structure-sensitive reaction.