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.

Catalytic Transformation of Biomass Derivatives to Value‐Added Chemicals and Fuels in Continuous Flow Microreactors

“…[347] The amination of (biobased) acids (e. g., succinic acid, itaconic acid, LA or 3-HPA) can produce pyrrolidones that are widely used for the synthesis of polymers, dyes, surfactants, pharmaceuticals and agrochemicals. [348][349][350] These gas-liquid reductive aminations may benefit from operation in microreactors by overcoming gas-liquid mass transfer limitations and having well-regulated temperature distribution for an intensified and more selective product formation. [348][349][350] These gas-liquid reductive aminations may benefit from operation in microreactors by overcoming gas-liquid mass transfer limitations and having well-regulated temperature distribution for an intensified and more selective product formation.…”

Study of 1D Titanate‐Based Materials –New Modification of the Synthesis Procedure and Surface Properties‐Recent Applications

“…Over the last decade, titania has undergone remarkable transformations in its shape and structure. Indeed, today titania may be found in the form of nanowires, nanofilms, nanoribbons, nanosheets, nanorods, and many others.…”

Cycloamination strategies for renewable N-heterocycles

“…Among the developed catalytic systems, noble metal catalysts (e.g., Pt/P-TiO 2 , Pt-MoO x /TiO 2 , Pt/TiO 2D , Ru/TiO 2 , Ir/SiO 2 -SO 3 H, and iridium complexes) are highly efficient for the cascade reaction process (up to 99% yield of pyrrolidones) under mild conditions (room temperature to 120°C, P(H 2 ) ≲1 MPa). [114][115][116][117][118][119][120] Apart from LA (22a) and primary amines, carbohydrates (e.g., glucose) and nitro compounds can be employed as the precursor of LA (22a) and nitrogen sources for producing pyrrolidones via additional acid-catalyzed hydrolysis and in situ hydrogenation steps, respectively. 121,122 The replacement of precious elements in Scheme 8 with abundant and low-cost metals is highly desirable, for which several well-designed base metal catalysts, such as Cu 15 /Al 2 O 3 doped with Pr (Cu 15 Pr 3 /Al 2 O 3 ), 123 carbon-supported FeNi nanoparticles, 124 and carbon nanotubes supported porous-carbon-coated Ni (CNF x @Ni@CNTs) 125 have been explored for synthesis of N-substituted pyrrolidones (up to 99% yield) from LA (22a) and amines although they require relatively harsh reaction conditions (130°C to 175°C, 1 to 5 MPa H 2 ).…”