Department of Chemical Engineering and Chemistry, Eindhoven University of Technology, P.O. Box 513, Eindhoven, The Netherlands.
Chemistry. 2012 Sep 17;18(38):12122-9. doi: 10.1002/chem.201202077. Epub 2012 Aug 14.
Efficient basic hydrotalcite (HT)-supported gold nanoparticle (AuNP) catalysts have been developed for the aerobic oxidative tandem synthesis of methyl esters and imines from primary alcohols catalyzed under mild and soluble-base-free conditions. The catalytic performance can be fine-tuned for these cascade reactions by simple adjustment of the Mg/Al atomic ratio of the HT support. The one-pot synthesis of methyl esters benefits from high basicity (Mg/Al = 5), whereas moderate basicity greatly improves imine selectivity (Mg/Al = 2). These catalysts outperform previously reported AuNP catalysts by far. Kinetic studies show a cooperative enhancement between AuNP and the surface basic sites, which not only benefits the oxidation of the starting alcohol but also the subsequent steps of the tandem reactions. To the best of our knowledge, this is the first time that straightforward control of the composition of the support has been shown to yield optimum AuNP catalysts for different tandem reactions.
高效的基本水滑石（HT）负载金纳米粒子（AuNP）催化剂已被开发出来，用于在温和且无可溶性碱条件下，催化伯醇经有氧氧化串联合成甲酯和亚胺。通过简单调整 HT 载体的 Mg/Al 原子比，可以精细调节这些串联反应的催化性能。一锅法合成甲酯得益于高碱性（Mg/Al = 5），而适度的碱性则大大提高了亚胺的选择性（Mg/Al = 2）。这些催化剂的性能远远优于之前报道的 AuNP 催化剂。动力学研究表明，AuNP 和表面碱性位之间存在协同增强作用，这不仅有利于起始醇的氧化，也有利于串联反应的后续步骤。据我们所知，这是首次表明通过直接控制载体的组成，可以得到用于不同串联反应的最佳 AuNP 催化剂。
