C/MgAl水滑石复合材料为前驱物所制催化剂在柠檬醛-丙酮缩合反应中的催化性能

Citral-acetone Condensation over Catalysts Prepared from C/MgAl Hydrotalcite Hybrids

在MgAl水滑石的合成体系中引入不同量的葡萄糖,得到了系列C/MgAl水滑石复合材料。该复合材料经550℃焙烧后,形成MgAl复合金属氧化物。该MgAl复合金属氧化物在含水的反应体系中可原位活化形成插层阴离子为OH-的MgAl水滑石催化剂(meixnerite)。采用XRD、N2吸附、元素分析和碱性能测试等手段对所制meixnerite催化剂的物化性能进行了表征。结果表明,以C/MgAl水滑石复合材料为前驱物所制备的meixnerite催化剂,较以常规的MgAl水滑石为前驱物所制催化剂具有较高的比表面和更多可接近的碱性位。这些特征使以C/MgAl水滑石复合材料为前驱物所制备的meixnerite催化剂在柠檬醛-丙酮缩合反应中的催化活性高于常规的以MgAl水滑石为前驱物所制备的催化剂。此外,本文还对合成体系中葡萄糖的引入量和反应条件对所制催化剂的催化性能的影响进行了考察。

A series of C/MgAl hydrotalcite hybrid materials were prepared by adding different amounts of glucose into the MgAl hydrotalcite synthesis system. Upon being calcined at 550 ℃, the as-synthesized hybrids were transferred into MgAl mixed oxides, and the MgAl mixed oxides could further in-situ transferred into MgA1 hydrotalcite analogues with OH- group in the interlayer＇s space （meixnerite） in the aqueous-containing reaction system. XRD, N2 adsorption, ICP, and benzoic acid titration were used to characterize the prepared samples. The results show that the meixnerite samples derived from C/MgAl hydrotalcite hybrids have higher surface areas, and more accessible basic sites than the sample derived from conventional MgAl hydrotalcites, which makes the former catalytically more active in citral-aetone condensation. In addition, the effects of the glucose amount in the synthesis system and the reaction conditions on the catalytic performances of the prepared catalysts were also investigated.