低负载量Fe基固体酸催化剂的制备及应用于苯酚羟基化

摘要

以HZSM-5分子筛为载体,采用浸渍法制备了用于苯酚羟基化反应制苯二酚的低负载量Fe基复合金属氧化物固体酸催化剂,研究了活性组分和助剂含量以及煅烧温度对催化剂性能的影响.实验结果表明,活性组分Fe以及助剂Cu,Sn,Mg的含量(基于载体的质量)分别为5.45％,3.65％,0.43％,0.68％时,在450℃下煅烧2h性能最优,苯酚转化率达到47.06％,邻苯二酚选择性达到62.28％,对苯二酚选择性达到23.81％,焦油选择性降至13.91％.XRD表征结果显示,活性组分Fe和助剂Cu,Sn,Mg在载体表面高度分散；NH3-IR表征结果显示,5.45％Fe-3.65％Cu-0.43％Sn-0.68％Mg/HZSM-5催化剂的总酸量为1.98 mmol/g,与苯酚羟基化反应相匹配,有效降低了焦油含量.%A series of Fe-based solid acid catalysts with low loading were prepared through impregnation method using HZSM-5 molecular sieves as the support and used in the hydroxylation of phenol to hydroquinone and catechol.The effects of active components,promoters and calcination temperature on the catalytic performance were studied.The results showed that the catalyst 5.45％Fe-3.65％Cu-0.43％Sn-0.68％Mg/HZSM-5(the Fe,Cu,Sn,Mg contents were based on the mass of the support) calcined at 450 ℃ for 2 h exhibited the best catalytic performance,and the phenol conversion,catechol selectivity,hydroquinone selectivity and tar selectivity were 47.06％,62.28％,23.81％ and 13.91％,respectively.The XRD result indicated that the active component Fe and promoters Cu,Sn,Mg were highly dispersed on the support.The NH3-IR result suggested that the 5.45％Fe-3.65％Cu-0.43％Sn-0.68％Mg/HZSM-5 catalyst with the total acid amount 1.98 mmol/g was fit for the hydroxylation of phenol,which could reduce the tar content effectively.