Catalysis Science & Engineering, Short talk
CE-026

Active Site Structures in Titanium-Silicalite 1: An NMR Point of View

C. P. Gordon1, A. Parvulescu2, J. H. Teles2, C. Copéret1*
1ETH Zürich, 2BASF SE

Titanium-Silicalite 1 (TS-1) is a unique oxidation catalyst that allows for the efficient activation of hydrogen peroxide (H2O2) as a terminal oxidant.[1] In particular, it allows for the catalytic epoxidation of propene on industrial scale leaving only water as byproduct. TS-1 has been studied in great detail, with the aim to understand the nature of the active sites that are still highly debated. Numerous studies based on both spectroscopic methods (IR, UV-VIS, EXAFS, NMR, XRD, neutron diffraction)[2] and computational approaches (MM, QM/MM, DFT)[3] led to isolated titanium peroxo and titanium hydroperoxo species being most commonly proposed as active sites.

Here, through the use of solid-state NMR spectroscopy augmented by computational studies and complementary spectroscopic methods, we will discuss the nature of the active sites in the TS-1 catalyst. Contrary to what is reported in the literature, non-isolated Ti sites are proposed to be key to the unique catalytic properties of TS-1.

[1] a) Bruno Notari, Catal. Today, 1993, 18, 163-172. b) Mario G. Clerici in Metal Oxide Catalysis. Eds. S. David Jackson, Justin S. J. Hargreaves, Wiley-VCH2009.
[2] Silvia Bordiga, Alessandro Damin, Francesca Bonino, Carlo Lamberti in Surface and Interfacial Organometallic Chemistry and Catalysis. Topics in Organometallic Chemistry. Eds. Christophe Copéret, Bruno Chaudret, Springer, 2005.
[3] Xavier Solans-Monfort, Christophe Copéret, Odile Eisenstein in Quantum Chemical Calculations of Surfaces and Interfaces. Eds. Vladimir A. Basiuk, Piero Ugliengo, American Scientific Publishers, 2009