制备了不同硅铁(钒)比的中孔分子筛Fe(V)-MCM-48,通过XRD、红外(IR)、氮气吸附-脱附和透射电镜(TEM)等分析手段对产物进行结构表征并研究了样品对苯羟基化制备苯酚的催化性能。结果表明,金属离子掺杂量以及制备过程中原料的加入顺序都对样品结构有很大影响。在适量金属掺杂量下,通过先加金属盐后加硅源的方法得到具有完好MCM-48型中孔特征结构的Fe(V)-MCM-48。以Fe-MCM-48或V-MCM-48为催化剂,双氧水作氧化剂,详细考察了金属掺杂量、催化剂用量和反应时间对苯羟基化反应的影响。结果表明,在70℃下反应时间6h时,苯/双氧水摩尔比为1:5,催化剂用量0.1g时,Fe-MCM-48(n(Si)/n(Fe)=40)和V-MCM-48(n(Si)/n(V)=20)具有较高的催化活性,苯的转化率分别为9.5%和9.7%。
The mesoporous molecular sieves Fe-MCM-48 and V-MCM-48 with different Si/M (M Fe or V) ratio were successfully prepared in a hydrothermal system. The products were characterized by means of X ray dif- fraction (XRD), Ne adsorption/desorption, IR and TEM. The results show that the solid simples have excel- lent crystalline structure and typical mesoporous characterization of MCM-48. It also indicates that Si/M and the adding order of reagents effect the structure of products effectively. By using Fe MCM-48 and V-MCM-48 as catalysts and H2 02 as oxidant, the activity of catalysts on hydroxylation of benzene discussed by observing the Si/M, the catalyst dosage and the reaction time. It shows that the products can efficiently catalyze the oxi- dation of benzene into phenol. Under the reaction condition of 0. lg catalyst, the mole ratio of n (H2()2) : n (benzene) = S, reaction temperature 70C and reaction time 6h, the conversation of benzene were 9. 5 and 9.7 by using Fe-MCM-48 (n(Si)/n(Fe)=-40) and V-MCM-48 (n(Si)/n(V)=20) respectively.