Solvent · polar aprotic
N-Methylpyrrolidone C5H9NO
Also: NMP
Not a common HPLC mobile-phase solvent (high UV cutoff ~285 nm and high boiling point limit it). Used as a strong dissolution/diluent solvent for poorly soluble analytes (polymers, dyes, pharmaceuticals, battery/electrode materials) prior to injection; sample-preparation solvent; headspace-GC matrix/dissolution solvent (e.g. pharma-grade 'for headspace GC' grades exist). Also widely used industrially for extractive distillation (selective for aromatics over aliphatics) and as a general polar aprotic process solvent.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C5H9NO
- CAS number
- 872-50-4
- UV cutoff
- 285 nm
- Snyder polarity index (P′)
- 6.7
- Selectivity group
- III
- Eluotropic strength ε° (silica)
- —
- Boiling point
- 202 °C
- Viscosity (25 °C)
- 1.65 cP
- Refractive index (nD²⁰)
- 1.4685
- Density
- 1.028 g/mL
- Water miscibility
- miscible
- USP <467> class
- Class 2
Safety
- reprotoxic (REACH Repr. 1B, SVHC)
- developmental toxicant / teratogen (in-utero developmental neurotoxicity is the ICH Q3C PDE-defining endpoint)
- combustible liquid (flash point ~86-95 C; not highly flammable)
- skin and eye irritant
- high-boiling polar aprotic solvent
Reference only. Solvents can be flammable, toxic, or peroxide-forming. Always consult the Safety Data Sheet (SDS) and your lab's protocols before handling.
What N-Methylpyrrolidone mixes with
Miscible with: 1-Propanol, 1,2-Dichloroethane, 1,4-Dioxane, 2-Propanol, Acetic acid, Acetone, Acetonitrile, Benzene, Carbon tetrachloride, Chloroform, Dichloromethane, Diethyl ether, Dimethyl sulfoxide, Ethanol, Ethyl acetate, Methanol, Methyl ethyl ketone, Methyl isobutyl ketone, MTBE, n-Butanol, n-Butyl acetate, N,N-Dimethylacetamide, N,N-Dimethylformamide, Pyridine, tert-Butanol, Tetrahydrofuran, Toluene, Triethylamine, Water.
Partially miscible with: Cyclohexane, Iso-octane, n-Heptane, n-Hexane, n-Pentane — mix only over a limited range.
Check any specific pair on the interactive miscibility chart.
Using N-Methylpyrrolidone in HPLC/GC
Not a common HPLC mobile-phase solvent (high UV cutoff ~285 nm and high boiling point limit it). Used as a strong dissolution/diluent solvent for poorly soluble analytes (polymers, dyes, pharmaceuticals, battery/electrode materials) prior to injection; sample-preparation solvent; headspace-GC matrix/dissolution solvent (e.g. pharma-grade 'for headspace GC' grades exist). Also widely used industrially for extractive distillation (selective for aromatics over aliphatics) and as a general polar aprotic process solvent.
Its Snyder polarity index is 6.7 (selectivity group III), and its UV cutoff of 285 nm limits low-wavelength UV detection.See what the polarity index means and the full UV cutoff table.
Sources
- University of Toronto (TRACES) — Burdick & Jackson — Solvent UV cutoff table (absorbance = 1 AU, 1 cm cell)
- Stenutz / L. R. Snyder — Solvent polarity index (P′) and selectivity groups
- NIST — Chemistry WebBook — thermophysical properties (BP, density, refractive index)
- PubChem (NIH/NLM) — Compound property records (physical constants, CAS, formula)
- USP <467> / ICH Q3C — Residual Solvents — solvent classification (Class 1/2/3)
Values are compiled from public references and were last verified July 2026. See ourmethodologyfor how we source and verify. Always confirm critical values against primary references and the SDS.
Related solvents
Other selectivity group III to compare with N-Methylpyrrolidone.