SSZ-60 : Synthetic Investigation and Catalytic Application to the Alkylation of Biphenyl and Naphthalene
SSZ-60 : Synthetic Investigation and Catalytic Application to the Alkylation of Biphenyl and Naphthalene
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SSZ-60 : 联苯和萘烷基化的合成研究和催化应用
DOI：
10.1016/j.micromeso.2011.03.023
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Y. Sugi
中科院分区：
文献类型：
--
作者：
H. Naiki;K. Komura;J.-H. Kim;G. Seo;Y. Sugi
将[B]-SSZ-24与铁进行同构取代，制备了具有AFI拓扑结构的硅酸亚铁[Fe]-SSZ-24，并将其应用于联苯（BP）的异丙基化反应，以了解其形状选择催化机理。用一定量的Fe(NO3)3·6H2O水溶液取代[B]-SSZ-24有效地得到了[Fe]-SSZ-24，其XRD显示出清晰的AFI拓扑结构，没有Fe2O3的峰。[Fe]-SSZ-24对BP的异丙化反应具有较强的催化活性。4,4′-二异丙基联苯（4,4′-DIPB）在中等温度（250 ~ 300℃）下可选择性形成；在高温（325 ~ 350℃）下，4,4′-DIPB的选择性降低。另一方面，无论反应温度和SiO2/ fe2o3的比例如何，封装产物中4,4 ' -DIPB的选择性几乎保持不变（约75%）。块状和封装产物对4,4′-DIPB的选择性差异表明，4,4′-DIPB的形状选择性形成发生在[Fe]-SSZ-24通道中，这些通道阻止了4,4′-DIPB的异构化，即使在350°C下也是如此。这些结果表明，SSZ-24通道可以在过渡态上区分4,4 ' -DIPB和其他可能的DIPB异构体，尽管高温会导致外部酸位异构化。AFI拓扑的大孔分子筛，[Fe]-SSZ-24, [Al]-SSZ-24, MgAPO-5， ZnAPO-5和SAPO-5，在BP的异丙化反应中对4,4 ' -DIPB具有相似的选择性。这些结果表明，尽管材料的催化活性取决于酸性，但AFI拓扑结构的框架主要控制4,4 ' -DIPB的形状选择性形成。
[Fe]-SSZ-24, a ferrosilicate with AFI topology, was prepared through an isomorphous substitution of [B]-SSZ-24 with iron, and applied for the isopropylation of biphenyl (BP) to understand the mechanism of shape-selective catalysis. The substitution of [B]-SSZ-24 with an aqueous solution of a limited amount of Fe(NO3)3·6H2O effectively gave [Fe]-SSZ-24, and its XRD gave clear patterns of AFI topology without the peaks assigned to Fe2O3. [Fe]-SSZ-24 exhibited enhanced catalytic activity for the isopropylation of BP. Shape-selective formation of 4,4′-diisopropylbiphenyl (4,4′-DIPB) occurred at moderate temperatures (250–300°C); however, the decreases of the selectivity for 4,4′-DIPB occurred at high temperatures (325–350°C). On the other hand, the selectivities for 4,4′-DIPB in encapsulated products remained almost constant (ca 75%), irrespective of the reaction temperature and the SiO2/Fe2O3ratios. The differences in the selectivities for 4,4′-DIPB between bulk and encapsulated products indicate that shape-selective formation of 4,4′-DIPB occurs in the [Fe]-SSZ-24 channels, and these channels prevent the isomerization of 4,4′-DIPB, even at 350°C. These results suggest that the channels of SSZ-24 can discriminate 4,4′-DIPB from other possible DIPB isomers at their transition states although high reaction temperatures cause isomerization at external acid sites. Large pore molecular sieves of AFI topology, [Fe]-SSZ-24, [Al]-SSZ-24, MgAPO-5, ZnAPO-5, and SAPO-5, gave similar levels of selectivities for 4,4′-DIPB in the isopropylation of BP. These results indicate that the framework of AFI topology primarily controls shape-selective formation of 4,4′-DIPB, although catalytic activities of the materials were dependent on acidic properties.