Synthesis of biobased N-methylpyrrolidone by one-pot cyclization and methylation of γ-aminobutyric acid

N-Methylpyrrolidone (NMP) is an industrial solvent that is currently based on fossil resources. In order to prepare It in a biobased way, the possibility to synthesize NMP from gamma-aminobutyric acid (GABA) was investigated, since GABA can be obtained from glutamic acid, an ammo acid that is present in many plant proteins Cyclization of GABA to 2-pyrrolidone and subsequent methylation of 2-pyrrolidone to NMP was achieved in a one-pot procedure, using methanol as the methylating agent and a halogen salt (i e ammonium bromide) as a catalyst. A selectivity above 90% was achieved, as well as a high conversion. Methylation of 2-pyrrolidone could also be done with dimethyl carbonate, but then the selectivity for NMP was less (67%)