Evaluating the per site activity of common mesoporous materials as supports for aminosilica catalysts for the aldol reaction and condensation
Evaluating the per site activity of common mesoporous materials as supports for aminosilica catalysts for the aldol reaction and condensation
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评估普通介孔材料作为氨基二氧化硅催化剂载体用于羟醛反应和缩合的每位点活性
DOI：
10.1016/j.apcata.2022.118997
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Brunelli, Nicholas A.
中科院分区：
文献类型：
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作者：
Brizes, Michael;Chen, Jee-Yee;Pineault, Hannah;Brunelli, Nicholas A.
介孔二氧化硅被认为是理想的体系，但它们是复杂的。这些材料可以用氨基硅烷功能化，以生产用于羟醛化学的高活性催化剂。尽管多相催化剂通常具有多个位置，但测试时假设每个位置对催化活性的贡献相等，则对功能化材料进行测试。在这里，我们对常见的介孔二氧化硅(MCM-41、MCM-48和SBA-15)进行官能化处理，并测定其逐位催化活性。如果SBA-15的微孔体积可以忽略不计(NMP-SBA-15)，则功能化的MCM-41、MCM-48和SBA-15的活性相似。场地量化数据显示，每种材料都有四种不同类型的场地。MCM-41具有最高比例的活性中心，但大多数活性中心都是低活性的。有趣的是，NMP-SBA-15的活性与MCM-41一样。与两种MCM材料相比，NMP SBA-15具有更高的高活性中心和中等活性中心比例。总体而言，每种材料都有相似的位置类型，尽管这些材料具有不同的孔结构和不同的孔大小。
Mesoporous silicas are regarded as ideal systems; however, they are complex. The materials can be functionalized with aminosilanes to produce highly active catalysts for aldol chemistry. Despite heterogeneous catalysts often having multiple sites, functionalized materials are tested assuming each site contributes equally to catalytic activity. Here, we functionalize common mesoporous silicas (MCM-41, MCM-48, and SBA-15) and determine the per site catalytic activity. The activity of functionalized MCM-41, MCM-48, and SBA-15 are similar if SBA-15 has negligible micropore volume (NMP-SBA-15). Site quantification data reveal that each material has four different types of sites. MCM-41 has the highest fraction of active sites; however, most sites are low activity. Interestingly, NMP-SBA-15 is as active as MCM-41. NMP SBA-15 has a higher fraction of high activity and medium activity sites than both MCM materials. Overall, each material has similar types of sites even though the materials have different pore structures and different pore sizes.