Oxidative Ring-Opening of Dimethylfuran in Zeolitic Imidazolate Frameworks through Computational Design.

Abstract

Furans are versatile feedstocks for producing valuable chemicals and fuels, with 2,5-dimethylfuran (DMF) particularly standing out for its potential in oxidative ring-opening reactions, yielding enediones. The zeolitic imidazolate framework ZIF-8 has shown promise as a mediator to achieve high selectivity, although a precise mechanistic understanding of how this heterogeneous system works is unclear. Here, we employ a computational protocol, combining a configurational search with force fields (GFN-FF) with a refinement at the periodic density functional theory (DFT) level, to model the oxidation of DMF with H2O2 and explicit MeOH solvent in the absence and presence of ZIF-8. In line with experimental observations, our results reveal that ZIF-8 suppresses overoxidation of the enedione cf. to results for the blank reaction. We further substituted the methyl group of ZIF-8 with other groups and tested the resulting materials in the above-mentioned reaction. We observe that vinyl-substituted ZIF emerges as the most selective material, while ZIF-H (SALEM-2) offers poor selectivity when compared with the blank reaction. A featurization study, correlating energy barriers and structural features, reveals how pore accessibility and linker geometry influence the selectivity. Our findings seek to deepen the understanding of molecular interactions in ZIFs and guide the rational design of MOFs for biomass conversion.