| 张学勤,何年志.Pt-Ir/Al2O3催化剂催化2-氧-4-苯基丁酸乙酯不对称加氢[J].分子催化,2013,(4):342-348 |
| Pt-Ir/Al2O3催化剂催化2-氧-4-苯基丁酸乙酯不对称加氢 |
| Asymmetric Hydrogenation of Ethyl 2-Oxo-4-Phenylbutyrate on Pt-Ir/Al2O3 Catalysts |
| 投稿时间：2013-05-20 修订日期：2013-06-16 |
| DOI： |
| 中文关键词: 2-氧-4-苯基丁酸乙酯 辛可尼定 铂 铱 双金属催化剂 |
| 英文关键词:ethyl 2-oxo-4-phenylbutyrate cinchonidine platinum iridium bimetallic catalyst |
| 基金项目:福建省自然科学基金（2012J05026）、福建省泉州市科技计划重点项目（2011N1） |
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| 中文摘要: |
| 用浸渍法制备了一系列γ-Al2O3负载的Pt、Ir单金属及不同Pt/Ir比例的双金属催化剂，在辛可尼定修饰下用于对2-氧-4-苯基丁酸乙酯不对称加氢合成(R)-2-羟基-4-苯基丁酸乙酯反应。运用XRD、TEM、TPR、XPS、UV-Vis等表征手段，对催化剂的物化性质进行了研究，并对Pt、Ir金属表面辛可尼定手性诱导机理进行了初步探讨。结果表明，金属组分在催化剂上分散均匀，无团聚现象，平均粒径为3-4nm; Pt-Ir/γ-Al2O3上Pt、Ir组分以单质形式存在; Ir作为作为低活性物种，在Pt/γ-Al2O3催化剂掺杂Ir组分遮盖和稀释了催化剂表面总体Pt活性位点数目，降低了Pt-Ir/γ-Al2O3催化剂加氢性能。辛可尼定在Pt、Ir表面的不同吸附行为（吸附方式、吸附强度、吸附构象）影响EOPB不对称加氢活性和对映选择性。 |
| 英文摘要: |
| A series of Pt/γ-Al2O3、Ir/γ-Al2O3 and Pt-Ir/γ-Al2O3 catalysts with different ratios of Pt and Ir were prepared by impregnation methods. The catalytic performance for asymmetric hydrogenation of ethyl 2-oxo-4-phenylbutyrate to ethyl (R)-2-hydroxy-4-phenylbutyrate was tested. The mechanism of chiral induction on cinchona-modified platinum and iridium catalysts and their physical and chemical properties were investigated by X-ray diffraction(XRD)，transmission electron microscopy(TEM), H2-temperature programmed reduction(H2-TPR),X-ray photoelectron spectroscopy(XPS) and ultraviolet-visible spectroscopy(UV-Vis). The average metal particles size for Pt/γ-Al2O3 and Pt-Ir/γ-Al2O3 catalysts were 3-4 nm；Pt and Ir existed as Pt(0) and Ir(0) for Pt-Ir/γ-Al2O3；Ir acted as an inactive species，covering and diluting the Pt active site in the surface. The results showed that a small amount of Ir obviously suppressed the hydrogenation activity and selectivity of Pt/γ-Al2O3. The notable differences in reaction rate and enantioselectivity of platinum and iridium attributed to different behaviour adsorption (adsorption strength，mode and conformation) of chiral modifier on the metal surface. |
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