Catalytic dehydration of glycerol to acrolein over sulfuric acid-activated montmorillonite catalysts
Catalytic dehydration of glycerol to acrolein over sulfuric acid-activated montmorillonite catalysts
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DOI：
10.1016/j.clay.2012.09.011
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发表时间：
2013-04
影响因子：
5.6
通讯作者：
Heng-yu Zhao;C. Zhou;L. Wu;Jianqiu Lou;Na Li;Huimin Yang;D. Tong;W. Yu
中科院分区：
文献类型：
--
作者：
Heng-yu Zhao;C. Zhou;L. Wu;Jianqiu Lou;Na Li;Huimin Yang;D. Tong;W. Yu
为了开发甘油催化脱水制丙烯醛的高效固体酸催化剂，研究了以硫酸活化的蒙脱土为原料制备的固体酸催化剂。蒙脱石在浓度为5- 40重量%的稀硫酸中活化。采用X射线衍射、酸度测定、N2吸附-脱附等温线和傅里叶变换红外光谱等方法，研究了硫酸处理对蒙脱石结构的影响。考察了硫酸活化的蒙脱土催化剂在甘油气相脱水反应中的催化性能，考察了反应温度、进料速度和甘油浓度等因素对催化性能的影响。蒙脱石粘土经硫酸活化后，其层状结构特征基本保持不变。在活化过程中，Ca ~（2+）-蒙脱石通过离子交换反应转化为H ~+-蒙脱石。甘油催化脱水的最佳反应条件为：温度320°C，液时空速18.5h-1，甘油溶液浓度10 wt.%，N2载气流量为10 mL/min，甘油转化率为54.2%，甘油收率为44.9wt.%丙烯醛在蒙脱土催化剂上的催化活性为10 wt.%硫酸溶液。酸活化蒙脱土催化剂层间的H+对甘油催化脱水反应起着关键作用。温度、液固空速和甘油浓度通过对反应机理、接触时间和反应平衡的影响而影响催化剂的性能。
For the development of efficient solid acid catalysts for the catalytic dehydration of glycerol to acrolein, catalysts made from montmorillonitic clay activated by sulfuric acid were investigated. Montmorillonite was activated in diluted sulfuric acid in the concentration range of 5–40wt.%. The effects of sulfuric acid treatment on the structure of the montmorillonite were characterized by X-ray diffraction, measurements of acidity, N2adsorption–desorption isotherms, and Fourier transform infrared spectroscopy. The catalytic behavior of sulfuric acid-activated montmorillonite catalysts in the gas-phase dehydration of glycerol were investigated under varying conditions, including the reaction temperature, the feed rate, and the concentration of glycerol. After montmorillonitic clay was activated by sulfuric acid, the layered structural features of montmorillonite remained nearly intact. Ca2+-montmorillonite was changed to H+-montmorillonite by ion exchange reaction during activation. The optimal catalytic glycerol dehydration reaction conditions were found to be: temperature at 320°C, liquid hourly space velocity (LHSV)=18.5h−1, concentration of glycerol solution=10wt.%, and the flow rate of N2carrier gas=10mL/min. A conversion of 54.2% of glycerol and a yield of 44.9wt.% acrolein were achieved over the montmorillonite catalyst activated by an aqueous 10wt.% sulfuric acid solution. The H+in the interlayer space of acid-activated montmorillonite catalysts played a critical role in the catalytic dehydration of glycerol. The temperature, the LHSV, and the concentration of glycerol affected the performance of the catalysts through their influence on the reaction mechanism, the contact time, and the reaction equilibrium.