Room temperature synthesis of N-substituted pyrrolidone from levulinic acid and nitrobenzene via a tandem hydrogenation and reductive amination process

Abstract

N-substituted pyrrolidone is one type of organic small molecules with high added values. The synthesis of N-substituted pyrrolidone via a tandem hydrogenation and reductive amination of biomass-derived levulinic acid (LA) with nitroarenes is an attractive route, but has rarely been reported, especially at room temperature. Herein, various Pt-based catalysts were used for the one-pot hydrogenation/reductive amination of LA with nitrobenzene and 96.0% yield of 5-methyl-N-phenyl-2-pyrrolidone (MNPP) was achieved over 0.5Pt/Nb2O5 at 30 °C, 24 h. Deep investigations demonstrated that the strongest ability of Nb2O5 to activate CO bond in LA and the hydrogenation ability of small size of Pt particles were the key factors to realize room temperature synthesis over 0.5Pt/Nb2O5. This Pt/Nb2O5 catalyst was reused 5 runs without obvious deactivation and it can be extended to various N-substituted pyrrolidone’s synthesis directly from LA and different nitroarenes at room temperature. This work would be helpful for designing more efficient reductive amination catalysts.