Developing novel catalysts that are able to achieve high space-time-yields is of considerable importance for the future development of more sustainable processes. In this respect, heterogeneous Lewis acid catalysts are known to catalyze a variety of industrially relevant reactions, such as liquid phase oxidations and isomerization reactions. Titanium silicalite-1 (TS-1) and Sn-beta zeolite are two important examples from this class of catalysts. Site isolation and uniform distribution of the Lewis acid centers, in combination with the unique hydrophobic pore architecture of the material, results in unrivalled catalytic performance.During this presentation, we will present model Sn catalysts, featuring well-defined SnIV-sites, and discuss the influence of site speciation, hydrophobicity and confinement on Lewis acid-mediated reactivity. For this, a grafting procedure is applied, anchoring SnIV to the surface of an amorphous silica support, followed by structural modifications of the active sites and its surroundings. Various spectroscopic techniques are combined with probe molecule adsorption studies and reactivity tests. Upon chemical tuning of a model-catalyst, it has been shown that a hydrophobic surface and intermediate-stabilizing forces inside zeolite pores all contribute to the overall catalytic performance in hydrogen-transfer reactions like the Meerwein-Ponndorf-Verley reaction of cyclohexanone with 2-butanol.

Active site speciation, surface polarity, and cavity effects on Lewis acid catalysis

248th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.