Solvent · polar protic
n-Butanol C4H10O
Also: 1-butanol
Moderately polar protic solvent used as an HPLC mobile-phase modifier and sample diluent, in normal-phase and ion-pair separations, and in solvent systems for sugars, amino acids, and polar analytes. Also a GC solvent/analyte, a common extraction and TLC-development solvent, and a general organic-synthesis/plasticizer feedstock. Its higher viscosity (~2.95 cP) raises HPLC backpressure, so it is used more as a modifier than a bulk mobile phase.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C4H10O
- CAS number
- 71-36-3
- UV cutoff
- 215 nm
- Snyder polarity index (P′)
- 3.9
- Selectivity group
- II
- Eluotropic strength ε° (silica)
- 0.7
- Boiling point
- 117.7 °C
- Viscosity (25 °C)
- 2.95 cP
- Refractive index (nD²⁰)
- 1.399
- Density
- 0.81 g/mL
- Water miscibility
- partial
- USP <467> class
- Class 3
Safety
- flammable (H226; flash point ~35-37 C)
- harmful if swallowed (H302)
- causes serious eye damage (H318)
- skin/eye irritant (H315)
- respiratory tract irritation (H335)
- may cause drowsiness or dizziness - CNS depressant (H336)
- not classified as a carcinogen
- not classified as reprotoxic
- not a peroxide-former
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-Butanol mixes with
Miscible with: 1-Propanol, 1,2-Dichloroethane, 1,4-Dioxane, 2-Propanol, Acetic acid, Acetone, Acetonitrile, Benzene, Carbon tetrachloride, Chloroform, Cyclohexane, Dichloromethane, Diethyl ether, Dimethyl sulfoxide, Ethanol, Ethyl acetate, Iso-octane, Methanol, Methyl ethyl ketone, Methyl isobutyl ketone, MTBE, n-Butyl acetate, n-Heptane, n-Hexane, N-Methylpyrrolidone, n-Pentane, N,N-Dimethylacetamide, N,N-Dimethylformamide, Pyridine, tert-Butanol, Tetrahydrofuran, Toluene, Triethylamine.
Partially miscible with: Water — mix only over a limited range.
Check any specific pair on the interactive miscibility chart.
Using n-Butanol in HPLC/GC
Moderately polar protic solvent used as an HPLC mobile-phase modifier and sample diluent, in normal-phase and ion-pair separations, and in solvent systems for sugars, amino acids, and polar analytes. Also a GC solvent/analyte, a common extraction and TLC-development solvent, and a general organic-synthesis/plasticizer feedstock. Its higher viscosity (~2.95 cP) raises HPLC backpressure, so it is used more as a modifier than a bulk mobile phase.
Its Snyder polarity index is 3.9 (selectivity group II), and its UV cutoff of 215 nm is low enough for most 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.