Solvent · polar aprotic
1,4-Dioxane C4H8O2
Also: dioxane
Polar aprotic ether solvent that is fully miscible with both water and virtually all organic solvents, so historically used as a bridging/modifier solvent in normal-phase and reversed-phase HPLC and as a versatile GC sample-injection solvent. Its moderate polarity (P' 4.8) and unusual all-round miscibility make it useful for dissolving samples spanning wide polarity ranges. Use in trace/UV work is limited by a relatively high UV cutoff, and modern use is declining sharply because of its carcinogenicity classification and strong tendency to form explosive peroxides.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C4H8O2
- CAS number
- 123-91-1
- UV cutoff
- 215 nm
- Snyder polarity index (P′)
- 4.8
- Selectivity group
- VIa
- Eluotropic strength ε° (silica)
- 0.49
- Boiling point
- 101.1 °C
- Viscosity (25 °C)
- 1.2 cP
- Refractive index (nD²⁰)
- 1.4224
- Density
- 1.033 g/mL
- Water miscibility
- miscible
- USP <467> class
- Class 2
Safety
- highly flammable (flash point ~12 C)
- suspected/possible human carcinogen (IARC Group 2B; NTP reasonably anticipated to be a human carcinogen)
- dangerous peroxide-former on exposure to air/light - can form explosive peroxides on storage and concentration
- harmful/toxic - target organs liver and kidney; irritant to eyes and respiratory tract
- may cause drowsiness/dizziness (CNS)
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 1,4-Dioxane mixes with
Miscible with: 1-Propanol, 1,2-Dichloroethane, 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-Butanol, n-Butyl acetate, n-Heptane, n-Hexane, N-Methylpyrrolidone, n-Pentane, N,N-Dimethylacetamide, N,N-Dimethylformamide, Pyridine, tert-Butanol, Tetrahydrofuran, Toluene, Triethylamine, Water.
Check any specific pair on the interactive miscibility chart.
Using 1,4-Dioxane in HPLC/GC
Polar aprotic ether solvent that is fully miscible with both water and virtually all organic solvents, so historically used as a bridging/modifier solvent in normal-phase and reversed-phase HPLC and as a versatile GC sample-injection solvent. Its moderate polarity (P' 4.8) and unusual all-round miscibility make it useful for dissolving samples spanning wide polarity ranges. Use in trace/UV work is limited by a relatively high UV cutoff, and modern use is declining sharply because of its carcinogenicity classification and strong tendency to form explosive peroxides.
Its Snyder polarity index is 4.8 (selectivity group VIa), 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.