Ambient Reductive Amination of Levulinic Acid to Pyrrolidones over Pt Nanocatalysts on Porous TiO₂ Nanosheets

Abstract

Construction of N-substituted pyrrolidones from biomass-derived levulinic acid (LA) via reductive amination is a highly attractive route for biomass valorization. However, realizing this transformation using H₂ as the hydrogen source under mild conditions is still very challenging. Herein, we designed porous TiO₂ nanosheets-supported Pt nanoparticles (Pt/P-TiO₂) as the heterogeneous catalyst. The prepared Pt/P-TiO₂ was highly efficient for reductive amination of LA to produce various N-substituted pyrrolidones (34 examples) at ambient temperature and H₂ pressure. Meanwhile, Pt/P-TiO₂ showed good applicability for reductive amination of levulinic esters, 4-acetylbutyric acid, 2-acetylbenzoic acid, and 2-carboxybenzaldehyde. Systematic studies indicated that the strong acidity of P-TiO₂ and the lower electron density of the Pt sites as well as the porous structure resulted in the excellent activity of Pt/P-TiO₂.