通过正交实验设计,改变钼酸铵溶液的质量分数、pH值和催化剂焙烧温度,利用共沉淀法制备了一系列Mo Bi Co Fe Ce Cs K复合氧化物催化剂。借助于BET、TG DSC、XRD等分析方法对催化剂的物理化学性质进行了表征。在常压连续流动固定床反应器中,系统地考察了上述三种制备条件对复合氧化物催化剂催化异丁烯选择性氧化生成甲基丙烯醛反应性能的影响。结果表明,大比表面积的催化剂具有较高的活性,而平均孔径小的催化剂选择性较差。催化剂的最佳制备条件为:钼酸铵溶液的质量分数10%、pH值2~3、焙烧温度500℃。在异丁烯∶空气=6∶94(体积比)、GHSV=3600h-1和360℃条件下,异丁烯转化率87.2%,甲基丙烯醛选择性72.0%,甲基丙烯醛收率62.7%。
Ionic liquid(IL),[bmim]PF6,was used in the reaction of one-step oxidative esterification from methacrolein to methyl methacrylate. It was found that ionic liquid not only increased the selectivity of methyl methacrylate but also inhibited its polymerization. The selectivity of methyl methacrylate was increased from 45% to 100% with ionic liquid. The experiment results showed that the content of ionic liquid had no effects on the selectivity of methyl methacrylate in a certain range of IL concentration,which indicated that ionic liquid could be used as a potential inhibitor of polymerization. [WT5HZ]