不同沉淀剂对制备邻苯基苯酚的Cu-Mg催化剂性能的影响

采用共沉淀法制备了用于环己烯基环己酮脱氢合成邻苯基苯酚的Cu-Mg催化剂，考察了不同共沉淀剂Na₂CO₃、NaOH、NaHCO₃、（NH₄）₂CO₃和H₂C₂O₄ 制备的Cu-Mg催化剂对催化活性和选择性的影响，利用XRD、BET、H₂-TPD、NH₃-TPD和CO₂-TPD等手段对催化剂进行表征。研究表明，催化剂制备中共沉淀剂种类对催化剂晶形结构、比表面积、表面酸、碱性和对氢吸附能力等影响显著，从而影响催化剂的活性和选择性；采用NaCO₃作共沉淀剂制备的Cu-Mg催化剂具有较大的比表面积，有利于MgO和活性组分Cu的分散，催化剂表面低温吸氢中心多，因而催化剂活性大，反应物转化率高，有利于降低催化剂表面强酸和强碱中心数，有利于抑制副反应，从而有利于提高生成邻苯基苯酚的选择性，在空速0.12 h^-1、H₂空速33 mL·（g·h）^-1和反应温度360 ℃条件下，环己烯基环己酮转化率达99.95%，邻苯基苯酚收率达95.23%。

Effect of precipitants on Cu-Mg catalysts for synthesis of o-phenylphenol

Cu/MgO catalysts used for synthesis of 〖WTBX〗o〖WTBZ〗 phenylphenol(OPP) via dehydrogennation of 〖WTBX〗o〖WTBZ〗 cyclohexenyl cyclohexanone were prepared by precipitation method. The effects of five precipitants［Na2CO3、NaOH、NaHCO3、（NH4）2CO3、H2C2O4］ on the catalytic activities of Cu/MgO catalysts and selectivity were studied. The catalysts were characterized by XRD, BET, H2 TPD, NH3 TPD and CO2 TPD techniques. The results showed that the precipitants affected the crystal structure, specific surface area, acidity and basity of the catalyst surface and hydrogen absorption, and then influenced the activity and selectivity of the catalysts. Cu/MgO catalysts coprecipitated by using Na₂CO₃ as precipitant had larger specific surface area beneficial to the dispersion of Cu and MgO, better adsorption capacity to H₂ at low temperature, and higher catalytic activities and conversion of o cyclohexenyl cyclohexanone than those coprecipitated by using the other precipitants. It was advantageous to decrease the amount of strong acidity and basicity, suppress the side reaction and improve the selectivity of OPP. The conversion of o cyclohexenyl cyclohexanone and yield of OPP were reached 99.95% and 95.23%, respectively, under the conditions of Na₂CO₃ as precipitant, reaction temperature 360 ℃, LHSV 0.12 h^-1 and H₂ space velocity 33 mL·(g·h)^－1.