采用尿素作为pH值自调节剂,一锅法合成了Fe-SBA-15催化剂.X射线衍射和N2吸附-脱附等温线结果表明,Fe-SBA-15具有与SBA-15相似的介孔结构.紫外-可见光谱结果表明,Fe-SBA-15样品在550℃焙烧后Fe元素主要以四配位形式存在.活性测试结果表明,Fe-SBA-15对苯及其衍生物的Friedel-Crafts苄基化反应具有优异的催化性能.例如,在反应温度为70℃和苯/苄基氯摩尔比为14.4的条件下,催化剂上苄基氯完全转化所需的时间为20~70min,二苯甲烷的选择性为97.8%~100%.随着反应温度的升高和Fe含量的增加,苄基氯的转化率逐渐升高;随着苯/苄基氯比的减小,苄基氯完全转化所需的时间逐渐延长.
Mesoporous Fe-SBA-15 samples with different Si/Fe ratios were prepared by one-pot synthesis using urea as a self-adjustor for pH values, The XRD patterns and nitrogen adsorption-desorption isotherms showed that the samples had similar mesoporous structure to SBA-15. The UV-Vis spectra showed that the iron atoms in the samples calcined at 550℃ were mainly tetrahedrally coordinated. The activity test results showed that the samples exhibited excellent catalytic performance in Friedel-Crafts benzylation of aromatics with benzyl chloride. For example, the Fe-SBA-15 samples took 20-70 min for the complete conversion of benzyl chloride with 97.8 %-100 % selectivity for diphenylmethane under the conditions of 70℃ and benzene/benzyl chloride molar ratio of 14.4. The conversion of benzyl chloride increased with increasing reaction temperature and iron content, whereas the time required for complete conversion of benzyl chloride increased with the decrease of the molar ratio of benzene to benzyl chloride.