Catalyst synthesis is an art where an inefficient material can be remarkably converted into a highly active and selective catalyst by adopting a suitable synthetic strategy to tune its properties during synthesis. The underlying principle of the strategy presented here is the integration of tailoring the structural and chemical behavior of tin phosphates with tuned catalytic active centers directed by employing different structure directing agents (SDAs) and the attempt to understand this in detail. It is demonstrated how soft templates can be effectively used for their so far unknown utilization of tuning the active sites in phosphate containing catalysts. We found that, by using an appropriate synthesis strategy, it is possible to tune and control explicitly both the catalyst morphology and the nature of active sites at the same time. The ³¹P MAS NMR study revealed that employing SDAs in the synthesis strongly influenced the nature and amount of phosphate species in addition to porosity. The resultant different nanostructured SnPO catalysts were investigated for one-pot synthesis of alkyl levulinates via alcoholysis of furfuryl alcohol. Among the catalysts, SnPO-P123 exhibited greater butyl levulinate yield via alcoholysis of furfuryl alcohol with n-butanol and the study was extended to synthesize different alkyl levulinates. Importantly, the active sites in the SnPO-P123 catalyst responsible for the reaction were elucidated by a study using 2,6-lutidine as a basic probe molecule. This study therefore provides an avenue for rational design and construction of highly efficient and robust nanostructured SnPO catalysts to produce alkyl levulinates selectively.

中文翻译：

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将软模板识别为磷酸锡多元调制中的刺激物及其在乙酰丙酸烷基酯合成中的催化作用

催化剂合成是一门技术，其中通过采用合适的合成策略在合成过程中调整其性能，可以将低效材料显着转化为高活性和选择性的催化剂。此处提出的策略的基本原理是通过采用不同的结构导向剂（SDA）来调整磷酸锡与调节的催化活性中心的结构和化学行为，并尝试进行详细了解。事实证明，软模板如何有效地用于迄今未知的调节含磷酸盐催化剂中活性位点的用途。我们发现，通过使用适当的合成策略，可以同时明确地调节和控制催化剂的形态和活性位点的性质。的³¹ P MAS NMR研究表明，在合成过程中使用SDA不仅会影响孔隙率，而且还会严重影响磷酸盐种类和性质。研究了通过糠醇的醇解一锅法合成乙酰丙酸烷基酯的不同纳米结构SnPO催化剂。在这些催化剂中，SnPO-P123通过糠醇与正丁醇的醇解显示出更高的乙酰丙酸丁酯收率。-丁醇的研究扩展到合成不同的乙酰丙酸烷基酯。重要的是，通过使用2，6-二甲基吡啶作为碱性探针分子的研究阐明了负责该反应的SnPO-P123催化剂中的活性位点。因此，本研究为合理设计和构建高效且坚固的纳米结构SnPO催化剂提供了途径，以选择性地生产乙酰丙酸烷基酯。