Bifunctional phosphines immobilized on inorganic oxides
Bifunctional phosphines immobilized on inorganic oxides
复制标题
固定在无机氧化物上的双官能膦
DOI：
10.1021/cm011018r
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发表时间：
2001
影响因子：
8.6
通讯作者：
J. Blümel
中科院分区：
文献类型：
--
作者：
C. Merckle;J. Blümel
双功能膦Ph_2P（CH_2）_3Si（OEt）_3被固定在MgO、TiO_2、Al_2 O_3和SiO_2表面上。用~（27）Al MAS、~（29）Si CP/MAS、~（31）P CP/MAS和~（31）P悬浮液NMR谱对材料进行了研究。MgO和TiO 2不能强烈地结合磷化氢，因此发生持续浸出。Al 2 O3以碱性、中性和酸性形式应用。所有这些都需要大量的洗涤，并发现酸性Al 2 O3的磷化氢浸出。以氧化铝和二氧化硅为载体，测定了膦的~（31）P悬浮NMR信号的半宽和化学位移，以研究膦的迁移率。因此，表面覆盖度，悬浮介质，酸度和孔径已经变化。虽然孔径（40 - 100 A）和酸度实际上对信号线宽度没有影响，但增加表面覆盖度会导致所有载体的线变窄。这被解释为刷式而不是毯式排列的结果。
The bifunctional phosphine Ph2P(CH2)3Si(OEt)3 has been immobilized on MgO, TiO2, Al2O3, and SiO2 surfaces. The materials were studied by 27Al MAS, 29Si CP/MAS, 31P CP/MAS, and 31P suspension NMR spectroscopy. MgO and TiO2 cannot bind the phosphine strongly, so persistent leaching occurs. Al2O3 was applied in the basic, neutral, and acidic versions. All of them needed extensive washing, and leaching of the phosphine was found for acidic Al2O3. With alumina and silica as the supports, the half-widths and chemical shifts of the 31P suspension NMR signals of the phosphine have been determined in order to investigate the mobilities of the phosphine moieties. Hereby the surface coverages, suspension media, acidities, and pore diameters have been varied. While the pore diameters (40−100 A) and acidities have practically no influence on the signal line widths, increasing surface coverage leads to narrower lines for all supports. This was interpreted as the result of brush-type rather than blanket-type arrangement...