Tungsten Species on Beta Zeolite with Abundant Silanol Nests for Efficient Olefin Metathesis

Abstract

Tungstate-based catalysts for olefin metathesis generally suffer from insufficient reaction rates, which require relatively high temperatures for the satisfied activities. This issue is mainly due to the shortage of active WO_x species related to intrinsic low adsorption and poor activation of olefin molecules. Herein, we found that the silanol nests in dealuminated Beta zeolite (DeAl-Beta) were favorable for high dispersion of tungsten species, forming active WO_x species on the zeolite, which was helpful for the adsorption and activation of olefin molecules, thus facilitating the generation of metallocycle intermediates. As a result, the propene yield in the metathesis of ethene and 1-butene over WO_x/DeAl-Beta was 2.3 times higher than that of the tungsten species supported on siliceous Beta zeolite with fewer silanol nests (WO_x/Si-Beta) under the equivalent conditions. A propene yield as high as >50% was achieved by optimizing the silanol nests in the WO_x/DeAl-Beta catalyst, outperforming those in the industrial silica supported tungsten species (W/SiO₂) catalysts reported previously.