Simultaneous construction of Zr-β zeolite with high content and high accessibility of framework Zr sites in the conversion of ethanol to 1,3-butadiene: Mechanisms and synergistic effects

Abstract

Metallosilicate zeolites, represented by Zr-β zeolite, possess unique porosity and tunable acidity, showing great potential in the conversion of ethanol to 1,3-butadiene. However, there still remains potential for further improvement of catalytic activity and stability by breaking the bottleneck framework metal site content and microporosity diffusion. In this paper, a novel Zr-β zeolite with both high content and high accessibility of framework Zr sites was successfully synthesized via the combination strategy of “Improved Decomposition Reconstruction” and “Silanization.” Based on the activity evaluation experiments of key reaction steps and in situ DRIFTS in the conversion of ethanol to 1,3-butadiene, the enhanced activity and stability are due to the synergistic effects of the content and accessibility of framework Zr sites, which both facilitate reactant conversion and inhibit the covering of active sites or the plugging of pore channels by polymerized heavy compounds. The prepared zeolite demonstrates excellent performance with a total conversion of 66% and a 1,3-butadiene selectivity above 67% in 100 h, along with good regenerability.