溶胶凝胶法制备含铁介孔催化剂用于二苯甲烷的合成

Synthesis of Diphenylmethane using Iron-containing Mesoporous Catalysts Prepared by Sol-gel Method

摘要:

本文采用溶胶凝胶法以柠檬酸铁为铁源合成含Fe纳米介孔材料。室温下凝胶样品60 ℃真空干燥后得到的干凝胶采用热重分析(TG)。最终400 ℃焙烧3 h得到介孔Fe₂O₃/SiO₂纳米粒子。合成材料的结构和性能采用XRD、N₂吸脱附、TEM、FT-IF、及H₂-TPR测试方法表征,结果显示合成了尺寸约50 nm的带有30-45? 介孔孔道的球形的Fe₂O₃/SiO₂纳米粒子,并且成功引入了高分散的Fe₃₊物种。催化性能是通过傅克烷基化法合成二苯甲烷的反应测试的,实验结果表明该催化剂具有优异的催化性能,高达100 % 苄基氯的转化率和相对较高的二苯甲烷的选择性,并且能够重复利用。

Abstract:

Using sol-gel method, the iron-containing nanocomposites with the ferric citrate as iron raw were synthesized. The clear sols were gelated at room temperature and then treated at 60 _oC in vacuum to get dry gels which were characterized by thermogravimetricSanalysis (TG). Finally, mesoporous Fe₂O₃/SiO₂ nanoparticles were obtained by the calciner at 400 _oC for 3h. The structural properties of synthesized particles were investigated by X-ray diffraction (XRD), N₂ adsorption-desorptionStechnique, transmission electron microscopy (TEM), Fourier-transform IR spectroscopy (FT-IR), and Temperature programmed reduction (H₂-TPR), which revealed that the iron active centers were successfully incorporated into the silica framework with spherical particles size about 50 nm and a average pore diameter of 30-45 ?. The catalytic activity of nanocatalysts had been tested in the synthesis diphenylmethane by Friedel-Crafts alkylation reaction. It found that the catalysts exhibited an excellent activity with 100% conversion of benzyl chloride and relatively higher selectivity to diphenylmethane, and could be reusedSmultiple times.