Solvent-free synthesis of bio-based N-isobutyl-5-methyloxazolidinone: an eco-friendly solvent

Oxazolidinones are five-membered N-heterocycle rings containing a carbamate moiety and are known for their industrial applications as antibiotics, herbicides and electrolytes in Li batteries. Considering the projected ecological transition, they have the potential to be recognized as a green solvent according to the European standards for bio-based solvents, if they can be synthesized via an eco-friendly synthetic route. Herein, a strategy is proposed for the kilogram scale synthesis of N-isobutyl-5-methyloxazolidinone (BMOX) in two steps, starting from the renewable resources from sugar industry and without using any organic solvent. The first step was the addition of bio-based isobutylamine to chloropropanol in basic aqueous solution to afford an amino-alcohol. In the second step, to this amino-alcohol, diethyl carbonate was added in the presence of a bio-based imidazolium salt catalyst to afford the desired oxazolidinone containing more than 62% bio-based carbon atoms. This study elucidates the physicochemical properties of this new bio-sourced oxazolidinone.