Synthesis, characterization and catalytic application of RuII–ethylenediamine complex—mesoporous silica as heterogeneous catalyst system in chemo-selective hydrogenation of α,β-unsaturated carbonyl compounds
Synthesis, characterization and catalytic application of RuII–ethylenediamine complex—mesoporous silica as heterogeneous catalyst system in chemo-selective hydrogenation of α,β-unsaturated carbonyl compounds
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DOI：
10.1016/j.micromeso.2005.06.042
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发表时间：
2005-12
影响因子：
5.2
通讯作者：
Anirban Ghosh;R. Kumar
中科院分区：
文献类型：
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作者：
Anirban Ghosh;R. Kumar
以有机功能化介孔分子筛（MCM-41和MCM-48）为载体，将Ru Ⅱ-膦配合物固定于MCM-41和MCM-48的内表面，合成了一种用于α，β-不饱和醛选择性加氢的多相催化剂体系.粉末XRD，SEM和TEM实验揭示了高度有序的六方和立方图案的有机改性的MCM-41和MCM-48材料，分别，即使在掺入钌配合物。此外，钌配合物锚定到介孔主体后，保留了完整性，这是由FTIR，31 P CP MAS NMR和XPS分析支持。该多相催化剂对α，β-不饱和醛的羰基加氢反应具有良好的活性和选择性。考察了反应温度、反应时间、氢气压力等因素对催化剂活性和选择性的影响。锚定的固体催化剂可以有效地回收并重复使用多次，而活性和选择性没有任何损失。虽然，当接枝到气相二氧化硅的有机改性表面上时，相同的Ru络合物的初始活性与相应的MCM-41/MCM-48催化剂相当，但由于浸出，催化剂在循环期间的活性和化学选择性显著降低。
An efficient heterogeneous catalyst system for chemo-selective hydrogenation of α,β-unsaturated aldehydes was synthesized, involving anchoring of a RuII–phosphine complex on the inner surfaces of organo-functionalized (propylamine and propylethylenediamine) mesoporous MCM-41 and MCM-48 materials. Powder XRD, SEM and TEM experiments reveal highly ordered hexagonal and cubic patterns of the organically modified MCM-41 and MCM-48 materials, respectively, even after incorporation of Ru complexes. Moreover, the integrity of the Ru complex was retained after anchoring into the mesoporous hosts, which was supported by FTIR,31P CP MAS NMR and XPS analyses. This heterogeneous catalyst shows promising activity and chemo-selectivity towards hydrogenation of carbonyl groups in α,β-unsaturated aldehydes. The effects of reaction temperature, reaction time and hydrogen pressure on the activity and selectivity were studied in detail. The anchored solid catalysts can be recycled effectively and reused several times without any loss in activity and selectivity. Although, the initial activity of the same Ru complex when grafted onto the organically modified surfaces of fumed silica is comparable to corresponding MCM-41/MCM-48 catalysts, the activity and chemo-selectivity significantly decrease during recycle of the catalyst due to leaching.