Catalytic conversion of biomass-derived levulinic acid (LA) into high-valued 5-methylpyrrolidones has become an attractive case in studies of biomass utilization. Herein, we developed a disordered mesoporous Pt/MNS catalyst for this reductive amination process under room temperature and atmospheric pressure of hydrogen. The disordered mesoporous structures in support of Pt/MNS catalyst led the formation of highly dispersed Pt species via confinement effect, providing high specific area for enhancing the catalytic sites. With the synergistic effect between highly dispersed Pt species and mesoporous structures, 5-methylpyrrolidones were successfully synthesized from biomass-derived LA and primary amines with high selectivity. Mechanism studies indicated that introducing protonic acid would promote the reductive-amination process, and enamine intermediates could be detected during the in-situ DRIFT tests. Density functional theory (DFT) calculation confirmed that the hydrogenation of enamine intermediate was more accessible than that of imide intermediates, leading the excellent performance of the Pt/MNS catalyst. This work provided a green method to produce 5-methylpyrrolidone and revealed the impact of catalyst structural characteristics on the reaction process.
Keywords: 5-Methylpyrrolidone; Amination; Hydrogenation; Levulinic Acid; Supported catalysts.
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