Solvent · low polarity
Toluene C7H8
Also: methylbenzene, PhMe
Common nonpolar/mid-strength solvent in normal-phase HPLC and as a mobile-phase modifier; frequent GC/GC-MS diluent and headspace solvent; UV cutoff (~285 nm) limits use as a UV-transparent HPLC solvent but it is a useful UV probe/marker; sample diluent for nonpolar analytes, polymers, oils and resins; extraction and dissolution solvent; common GC calibration/reference and residual-solvent (USP <467> Class 2) analyte.
Compiled by Hemant RawatLast reviewed July 2026How we verify
Properties
- Formula
- C7H8
- CAS number
- 108-88-3
- UV cutoff
- 285 nm
- Snyder polarity index (P′)
- 2.4
- Selectivity group
- VII
- Eluotropic strength ε° (silica)
- 0.22
- Boiling point
- 110.6 °C
- Viscosity (25 °C)
- 0.56 cP
- Refractive index (nD²⁰)
- 1.4969
- Density
- 0.8669 g/mL
- Water miscibility
- immiscible
- USP <467> class
- Class 2
Safety
- highly flammable liquid and vapor
- reprotoxic (repro. tox. Cat. 2, suspected damage to unborn child)
- aspiration hazard (may be fatal if swallowed and enters airways)
- CNS depressant / neurotoxic on repeated exposure (STOT RE)
- skin and eye irritant
- not classified as carcinogen (IARC Group 3)
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 Toluene 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, 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, Triethylamine.
Partially miscible with: Dimethyl sulfoxide — mix only over a limited range.
Immiscible with: Water — these form two layers.
Check any specific pair on the interactive miscibility chart.
Using Toluene in HPLC/GC
Common nonpolar/mid-strength solvent in normal-phase HPLC and as a mobile-phase modifier; frequent GC/GC-MS diluent and headspace solvent; UV cutoff (~285 nm) limits use as a UV-transparent HPLC solvent but it is a useful UV probe/marker; sample diluent for nonpolar analytes, polymers, oils and resins; extraction and dissolution solvent; common GC calibration/reference and residual-solvent (USP <467> Class 2) analyte.
Its Snyder polarity index is 2.4 (selectivity group VII), 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 VII to compare with Toluene.