Sulfur-Modified SBA-15 Supported Amorphous Palladium with Superior Catalytic Performance for Aerobic Oxidation of Alcohols
Sulfur-Modified SBA-15 Supported Amorphous Palladium with Superior Catalytic Performance for Aerobic Oxidation of Alcohols
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DOI：
10.1007/s10562-013-1184-2
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发表时间：
2014-01
影响因子：
2.8
通讯作者：
Kun Liu;Zhaoxiang Chen;Zhiqiang Hou;Yuanyuan Wang;L. Dai
中科院分区：
文献类型：
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作者：
Kun Liu;Zhaoxiang Chen;Zhiqiang Hou;Yuanyuan Wang;L. Dai
摘要制备了一系列硫改性SBA-15负载非晶态钯催化剂，系统考察了制备条件对苯甲醇有氧氧化反应的影响。优化后的催化剂具有较高的催化活性（转化率100%，选择性99%），且分离方便。通过X射线衍射、BET、ICP、X射线光电子能谱、CO化学吸附和透射电镜等手段对催化剂进行了表征，结果表明，催化剂中的二硫键骨架既是稳定的连接体，又是Pd物种的良好螯合剂。随着硫键间碳链长度的增加，Pd ~（2+）被还原为Pd ~（0+），这是催化剂失活的原因。其机理是碱从配位醇中夺取一个质子，形成Pd醇化物物种，随后进行β-氢化物消除，得到苯甲醛，这一点已被催化和特征结果所证实。图形摘要
AbstractA series of sulfur-modified SBA-15 supported amorphous palladium catalysts are prepared, and the effects of preparation parameters on the aerobic oxidation of benzyl alcohol are systematically investigated. The optimal catalyst exhibits remarkably enhanced catalytic activity (conversion 100 % and selectivity 99 %) and could be separated conveniently. The catalysts are characterized by X-ray diffraction patterns, BET, ICP, X-ray photoelectron spectroscopy, CO chemisorption and transmitting electron microscopy, and the results show that disulfur bond framework in the optimal catalyst act as both a stable linker and a good chelator for Pd species. Pd2+is reduced to Pd0with the increasement of the carbon chain lengths between sulfur bonds, which is the cause of deactivation. The mechanism is that a base abstracts a proton from the coordinated alcohol to form a Pd alcoholate species that subsequently undergo β-hydride elimination to give benzyl aldehyde, which is confirmed by the catalytic and characteristic results.Graphical Abstract