Sustainable Catalytic Synthesis for a Bio-Based Alternative to the Reach-Restricted N-Methyl-2-Pyrrolidone

The catalytic conversion of biomass and its derivatives into valuable chemicals requires efficient, energy saving, and sustainable technologies. In this work, a variety of bifunctional catalysts are prepared combining immobilized metal nanoparticles and acid solid materials featuring Lewis or Brønsted acidity. The catalytic systems are tested in the reductive amination of bio-derived levulinates with primary amines, using hydrogen as clean reducing agent, to obtain N-substituted-5-methyl-2-pyrrolidones, which are proposed as substitutes for the widely used, REACH-restricted solvent N-methyl-2-pyrrolidone. The overall process is studied in depth to identify the best combination of metal and acid functionalities to be used in one-pot and one stage. Pt immobilized onto the Brønsted solid acid Aquivion is shown to be the most efficient catalyst, with a productivity of N-heptyl-5-methyl-2-pyrrolidone of 7.9 mmolgcat-1 h-1 reached at full conversion and 98.6% selectivity, under 120 °C, 4 bar H2 pressure and solvent-free conditions.