用于低温液相合成甲醇的Cu/MgO/ZnO催化剂

采用并流共沉淀法制备了不同Cu:(Mg+Zn)及Mg:Zn摩尔比的铜基催化剂Cu/MgO/ZnO，用于低温液相甲醇的合成，并对比了Cu/ZnO及Cu/MgO催化剂，分析了催化剂中载体MgO的作用. 结果表明，MgO的引入有利于催化剂中Cu+的生成并均匀分散在载体中，可提高催化剂的催化活性. 以合成气CO+H2为原料，在443 K和5.0 MPa条件下，采用液体石蜡作溶剂，考察了催化剂的催化性能. 结果表明，Cu/MgO/ZnO催化剂的活性优于Cu/ZnO和Cu/MgO催化剂，且当Cu:Mg:Zn=2:1:1时催化性能最好，此时合成气中CO的转化率为63.56%，甲醇的选择性为99.09%，时空收率为5.413 mol/(kg×h). 分析了Cu/MgO催化剂在高温反应条件下的失活现象，认为铜烧结是其失活的主要原因.

Study on Cu/MgO/ZnO Catalyst for Low-temperature Synthesis of Methanol

A series of Cu/MgO/ZnO catalysts with different Cu:(Mg+Zn) and Mg:Zn molar ratios were prepared by conventional co-precipitation method, which are used for low-temperature methanol synthesis. And Cu/ZnO and Cu/MgO catalysts were prepared as well. Comparison was made among them by characterization. Addition of MgO to Cu/ZnO catalyst could introduce more dispersed Cu+ sites, therefore the catalytic activity was promoted. At 443 K and 5.0 MPa, the activities of prepared catalysts were tested in a slurry reactor using liquid paraffin as solvent. The results indicated that the activity of Cu/MgO/ZnO catalyst was superior to that of Cu/ZnO and Cu/MgO, and when Cu:Mg:Zn=2:1:1, the catalyst had the highest activity: the conversion rate of CO was as high as 63.56%, and the selectivity and space time yield of methanol reached 99.09% and 5.413 mol/(kg×h) respectively. The deactivation phenomenon of Cu/MgO/ZnO catalyst was observed under high reaction temperature, and the characterization results indicated that it was due to the sintering of Cu particles.