Direct immobilization of triphenylphosphine palladium complexes on the external surface of zeolite β
Direct immobilization of triphenylphosphine palladium complexes on the external surface of zeolite β
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三苯基膦钯配合物直接固定在β沸石外表面
DOI：
10.1016/j.micromeso.2019.109571
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发表时间：
2019
影响因子：
5.2
通讯作者：
Yuito Koga
中科院分区：
文献类型：
--
作者：
Kazu Okumura;Kakeru Sato;Keisuke Kamioka;Yuito Koga
用一种简单的方法将Pd络合物固定在若干支撑物上。为此，双（三苯基膦）二氯化钯（Pd(PPh3)2Cl2）与几种氧化物（包括MgO， γ-Al2O3， TiO2和沸石）结合。Pd K-edge x射线吸收精细结构光谱（XAFS）分析表明，β沸石上负载的Pd(PPh3) 2cl2基本保持完整，而配合物完全分解，在MgO和γ-Al2O3上提供金属Pd或PdO。在β沸石上加载Pd(PPh3) 2cl2后，其比表面积略有降低，这可能是由于配合物在外表面沉积所致。通过吸附三苯基膦（PPh3）的对比实验，推测Pd(PPh3) 2cl2的PPh3配体被插入到靠近外表面的β沸石孔中。与原始Pd(PPh3)2Cl2相比，固定在β沸石上的Pd配合物具有更高的烯丙基烷基化活性。用甲苯漂洗后，负载Pd配合物的沸石β可以回收。在β沸石上加入少量白光孔雀石绿（LMG）或白光结晶紫（LCV）可提高Pd配合物的活性。
The immobilization of a Pd complex on several supports was attempted using a simple method. For this purpose, bis(triphenylphosphine)palladium(II) dichloride(Pd(PPh3)2Cl2) was attached to several oxides including MgO, γ-Al2O3, TiO2, and zeolites. Pd(PPh3)2Cl2supported on zeolite β remained mostly intact, whereas the complex completely decomposed to provide metal Pd or PdO on MgO and γ-Al2O3, as analyzed by Pd K-edge X-ray absorption fine structure spectroscopy (XAFS). The specific surface area was slightly reduced after Pd(PPh3)2Cl2loading on zeolite β, probably due to the deposition of the complex on the external surface. From a comparison experiment using the adsorption of triphenylphosphine (PPh3), it was supposed that the PPh3ligand of Pd(PPh3)2Cl2was inserted into the pores of zeolite β located close to the external surface. The Pd complexes immobilized on zeolite β exhibited much higher activity for allylic alkylation compared with that of pristine Pd(PPh3)2Cl2. Recycling of the zeolite β loaded Pd complex was possible after the used catalyst was rinsed with toluene. The activity of the Pd complex loaded on zeolite β was enhanced by the addition of a small amount of leucomalachite green (LMG) or leucocrystal violet (LCV).