Selective Activation of Alcohols in the Presence of Reactive Amines over Intermetallic PdZn: Efficient Catalysis for Alcohol-Based N-Alkylation of Various Amines
Selective Activation of Alcohols in the Presence of Reactive Amines over Intermetallic PdZn: Efficient Catalysis for Alcohol-Based N-Alkylation of Various Amines
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DOI：
10.1021/acscatal.6b01677
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发表时间：
2016-09-01
期刊：
影响因子：
12.9
通讯作者：
Komatsu, Takayuki
中科院分区：
文献类型：
--
作者：
Furukawa, Shinya;Suzuki, Ryohei;Komatsu, Takayuki
制备了负载在Al 2 O3上的Pd基金属间化合物（PdxMy/Al 2 O3）（其中M = Bi、Cu、Fe、Ga、In、Pb、Sn或Zn），并将其用作在活性胺存在下选择性活化醇的催化剂，这是具有高度挑战性的，并且是基于醇的胺的N-烷基化的关键策略。虽然Pd/Al 2 O3催化剂表现出高的催化活性，但发生不希望的副反应，如胺二聚（通过胺活化）和C-O键断裂，导致N-烷基化产物的产率低。相比之下，PdZn/Al 2 O3催化剂作为一个有效的催化剂，该反应，显示出高的催化活性，选择性，原子效率和广泛的底物范围。详细的动力学和计算研究表明，Pd的相对亲和力的醇和胺的急剧变化的PdZn金属间相的形成。在单钯上，胺的吸附和活化在热力学和动力学方面分别优于醇。然而，这种趋势是相反的PdZn，允许优先吸附和活化的醇，因此，选择性的N-烷基化。
Pd-based intermetallic compounds supported on Al2O3 (PdxMy/Al2O3) where M = Bi, Cu, Fe, Ga, In, Pb, Sn, or Zn) were prepared and tested as catalysts for the selective activation of alcohols in the presence of reactive amines, which is highly challenging and is the key strategy for alcohol-based N-alkylation of amines. Although the Pd/Al2O3 catalyst exhibited a high catalytic activity, undesired side reactions such as amine dimerization (via amine activation) and C-O bond scission occurred, resulting in a poor yield of the N-alkylation product. In contrast, the PdZn/Al2O3 catalyst acted as an efficient catalyst for this reaction, displaying high catalytic activities, selectivities, and atom efficiencies and a wide substrate scope. Detailed kinetic and computational studies revealed that the relative affinity of Pd for alcohol and amine drastically changes by the formation of a PdZn intermetallic phase. On monometallic Pd, the adsorption and activation of amines are preferred over those of alcohols in terms of thermodynamic and kinetic aspects, respectively. However, this trend is inverted on PdZn, allowing preferential adsorption and activation of alcohols and, hence, selective N-alkylation.