Synthesis and Nuclear Magnetic Resonance Study of Boron-Modified MCM-41 Mesoporous Materials
Synthesis and Nuclear Magnetic Resonance Study of Boron-Modified MCM-41 Mesoporous Materials
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DOI：
10.1021/j100044a026
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发表时间：
1995-11
期刊：
影响因子：
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通讯作者：
A. Sayari;I. Moudrakovski;C. Danumah;C. Ratcliffe;J. Ripmeester;K. F. Preston
中科院分区：
文献类型：
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作者：
A. Sayari;I. Moudrakovski;C. Danumah;C. Ratcliffe;J. Ripmeester;K. F. Preston
合成了硼改性的介孔材料MCM-41，并对其进行了核磁共振表征。1* B MAS NMR数据表明，即使在Si/B比低至6.25的样品中，合成样品中的硼原子也以四配位状态存在。29 Si MAS NMR的结果表明，通过与结构羟基的相互作用，硼与晶格的连接发生。煅烧后硼主要以三方配位状态存在，只有少量的硼以四面体配位状态存在。发现部分硼与晶格连接较弱，在室温下，在潮湿空气中水解可容易地除去。水解过程通过13 Bmas NMR监测。硼的剩余部分与晶格紧密结合，可以承受严格的处理。
Boron-modified mesoporous materials MCM-41 have been synthesized and characterizedby nuclear magnetic resonance(NMR) spectroscopy. 1* B MAS NMR data show that all the boronin the as-synthesized samples is present in the four-coordinated state even in samples with Si/B ratios as low as 6.25. Results of 29Si MAS NMR suggest that attachment of boron to the lattice takes place through interaction with structural hydroxyl groups. After calcination, the boron is present mainly in a trigonal coordination state, and only a small amount remainedtetrahedrally coordinated. It was found that part of the boron is weakly connected to the lattice and can be easily removedby hydrolysis in moist air at room temperature. The process of hydrolysis was monitored by” Bmas NMR. The remaining part of the boron is strongly bound to the lattice and can withstand severe treatments.