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 -aminobutyric acid (GABA) was investigated, since GABA can be obtained from glutamic acid, an amino 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%).
- dimethyl carbonate
Lammens, T. M., Franssen, M. C. R., Scott, E. L., & Sanders, J. P. M. (2010). Synthesis of biobased N-methylpyrrolidone by one-pot cyclization and methylation of c-aminobutyric acid. Green Chemistry, 12(8), 1430-1436. https://doi.org/10.1039/c0gc00061b