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.