Sustainable Efficient Synthesis of Pyrrolidones from Levulinic Acid over Pd/C Catalyst

Abstract

The synthesis of 5‐methyl‐2‐pyrrolidone through reductive amination of levulinic acid (LA) with ammonium formate (AF) as a source of both hydrogen and nitrogen over Pd/C catalyst was investigated. The effects of various reaction parameters, such as solvent, catalyst dosage, ammonium formate amount and temperature on the conversion of LA into 5‐methyl‐2‐pyrrolidone (MPD) were systematically investigated. The results showed that a MPD yield as high as 98 % was obtained in water at 180 °C for 4 h under a low metal content (0.28 mol% Pd relative to LA), which is higher than many previous reports. The Pd/C catalyst could be reused for at least 9 times with only a slight loss in activity. Meanwhile, Pd/C catalyst was efficient for the conversion of LA/ester into various N‐substituted‐5‐methyl‐2‐pyrrolidones (80–93 % yield) by using a mixture of formic acid and the corresponding primary amines.