(175b) Theoretical Insights into the Selective Conversion of Tetrahydrofuran to 1,3-Butadiene on ZrO2

1,3-Butadiene is an important industrial chemical used in the manufacture of automobile tires. The current production methods, mainly steam cracking of naphtha and shale gas, are energy-intensive, less selective and produce large amounts of CO₂.^1-2 Renewable biomass-based production of 1,3-butadiene could potentially be a sustainable and energy-efficient alternative due to lower reaction temperaturesand green-house gas emissions.^1-2 Out of the various possible catalytic chemical routes, conversion of biomass to butadiene via ethanol, and four-carbon alcohols have been widely explored.^1-2

A recent method, which has emerged as an alternative, converts tetrahydrofuran (THF) into 1,3-butadiene by dehydra-decyclization over Brønsted acid zeolites.^3-5 Remarkably, we have recently discovered that the dehydra-decyclization of THF to butadiene can be selectively performed (selectivity over 90%) on ZrO₂, a catalyst not typically thought of as Brønsted acidic.

In this paper, we perform Density-Functional theory calculations and microkinetic modelling to gain mechanistic insights into the high performance of ZrO₂. We consider the structural complexity of tetragonal and monoclinic ZrO₂ and investigate the catalytic activity of isolated Lewis acid-base pairs, the possible catalytic activity of Brønsted hydroxyls and the synergy of the two types of sites for two pathways: (a) the main reaction to butadiene; and (b) the retro-Prins condensation to propene and formaldehyde, the dominant side reaction.

References:

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2. S. Farzad, M.A. Mandegari, and J.F. Görgens, Bioresour. Technol. 239, 37 (2017).
3. X. Li, P. Jia, and T. Wang, ACS Catal. 6, 7621 (2016).
4. O.A. Abdelrahman, D.S. Park, K.P. Vinter, C.S. Spanjers, L. Ren, H.J. Cho, D.G. Vlachos, W. Fan, M. Tsapatsis, and P.J. Dauenhauer, ACS Sustain. Chem. Eng. 5, 3732 (2017).
5. S. Li, O.A. Abdelrahman, G. Kumar, M. Tsapatsis, D.G. Vlachos, S. Caratzoulas, and P.J. Dauenhauer, ACS Catal. 9, 10279 (2019).