Institute for Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 1, CH-8093 Zurich, Switzerland.
Chem Soc Rev. 2015 Oct 21;44(20):7025-43. doi: 10.1039/c5cs00028a. Epub 2015 Apr 28.
The catalytic conversion of renewable feedstocks into chemicals is pursued as a means to sustainably fulfil future societal needs. Due to the oxygen-rich nature of bio-derived substrates, isomerisation, transfer-hydrogenation and retro-aldol reactions have emerged as relevant transformations to produce commodity chemicals and polymer building blocks. In this context, porous materials containing Lewis-acid metals (e.g., Al, Ga, Sn, Ti, Zr) play an important role. Among these, tin-containing zeolites have demonstrated superior catalytic properties which have mainly been attributed to their hydrophobicity and crystallinity. This review evaluates the versatility and the scalability of bottom-up and top-down approaches to introduce Lewis-acid functionalities in zeolitic matrices. A precise characterisation is shown to be crucial to determine the structure, acidity and environment of the sites introduced. In this regard, we highlight the limitations of conventional techniques and the advantages of analytical and modelling tools recently applied to gain an improved understanding of these solids. Thereafter, property-performance relations and important aspects for the industrial amenability of new synthetic routes are exemplified through case studies. Finally, we put forward the need for gathering deeper knowledge of the site location, surface properties and stability to aid the design of next-generation Lewis-acid catalysts.
将可再生原料转化为化学品是一种可持续的方法，可以满足未来社会的需求。由于生物衍生底物中富含氧，异构化、转移氢化和反醛缩合反应已成为生产大宗商品化学品和聚合物结构单元的相关转化反应。在这种情况下，含有路易斯酸金属（如 Al、Ga、Sn、Ti、Zr）的多孔材料发挥着重要作用。在这些材料中，含锡沸石表现出优异的催化性能，这主要归因于其疏水性和结晶性。本综述评估了在沸石骨架中引入路易斯酸功能的自下而上和自上而下方法的多功能性和可扩展性。精确的表征对于确定引入的位点的结构、酸度和环境至关重要。在这方面，我们强调了传统技术的局限性以及最近应用于深入了解这些固体的分析和建模工具的优势。然后，通过案例研究说明了新合成路线的性能-性能关系和对工业适用性的重要方面。最后，我们提出需要深入了解位点位置、表面性质和稳定性，以帮助设计下一代路易斯酸催化剂。
