N-Methylpyrrolidone Synonym(s): 1-Methyl-2-pyrrolidinone, 1-Methyl-2-pyrrolidone, N-Methyl-2-pyrrolidone, NMP Empirical Formula (Hill Notation): C5H9NO CAS No.: 872-50-4 Molecular Weight: 99.13 EC No.: 212-828-1