What is Tetrahydrofuran (THF)?

Tetrahydrofuran, THF, is a heterocyclic compound with oxygen. The molecular formula for THF is (CH2)4O. It is a colorless liquid.

Heterocyclic compounds are cyclic hydrocarbons that contain an atom in the ring of a cyclic other than a carbon atom, hence the prefix "hetero". — These atoms could be sulphur, nitrogen, or oxygen.

THF is a moderate polar aprotic solvent based on its cyclic structure that locks in its polarity. The oxygen atom in THF is available to accept hydrogen bonding making it high soluble on water.

THF can dissolve a wide variety of organic compounds. For that reason, it is a popular solvent choice for small-scale laboratory experiments. Its low boiling point also makes it easy to remove from chemical reactions by evaporation.

Sigma Aldrich Tetrahydrofuran Lewis Structure


Whether you need tetrahydrofuran in HPLC , ACS, anhydrous tetrahydrofuran or one of the other grades available, we offer the right product for your application.


Tetrahydrofuran Formulas and Structures

THF's structure comprise four carbon atoms, eight hydrogen atoms, and one oxygen atom.


Type Formula or Structure
Tetrahydrofuran Molecular Formulas C4H8O or (CH2)3CH2O
Tetrahydrofuran Ball and Sticks Structural Model Sigma Aldrich Tetrahydrofuran Ball-Stick Structure
Tetrahydrofuran Sticks Structural Model Sigma Aldrich Tetrahydrofuran Stick Structure
Tetrahydrofuran Skeletal Structural Model Sigma Aldrich Tetrahydrofuran Skeletal Structure
Tetrahydrofuran Spce-Filling Structural Model Sigma Aldrich Tetrahydrofuran Space-Filling Structure

Tetrahydrofuran Identification

Chart listing the various names, identifiers and synonyms of tetrahydrofuran.

ID Type Identification
Synonym THF, Tetrahydrofuranne, Tetraidrofurano, Tetrahydrofuraan, Oxolane
Molecular Formula C4H8O
CAS Number 109-99-9
Beilstein Registry
EG/EC Number 2037268
MDL Number MFCD00005356
RIDADR UN 2056 3/PG 2



Tetrahydrofuran Physical and Chemical Properties

Chart including the physical and chemical properties of tetrahydrofuran.

Property Value
Molecular Weight 72.11
Density 0. 889 g/mL at 25 ºC
Boiling Point 65-67 ºC
Melting Point -108 ºC
Flash Point -17.2 ºC
Viscosity (cP)
0.456 at 25 ºC
Dielectric Constant 7.52 at 22 ºC
Dipole Moment 1.750
UV cutoff 220 nm
Refractive Index 1.407 at 20 ºC
Vapor Pressure 143 mm Hg (20 °C)
Vapor Density 2.5 (vs. air)
Water Solubility Greater than or equal to 100 mg/mL at 68° F (NTP, 1992)
Heat of Combustion -14,990 BTU/lb = -8330 cal/g = -348.8X10+5 J/kg 
Heat of Vaporization 180 BTU/lb= 98.1 cal/g= 4.1X10+5 J/kg 
Surface Tension 26.4 dyn/cm at 25 °C 

Tetrahydrofuran Miscibility and Immiscibility

Property Chemical
Miscible Acetic Acid, Acetone, Acetonitrile, Benzene, Butanol, Methyl ethyl ketone (MEK), Butyl Acetate (n-), methyl tert-butyl ether (MTBE), Carbon Tetrachloride, Chloroform, Cyclohexane, Dichloroethane (1, 2), Dichloromethane, Diethyl ether, Diisopropyl ether, Dimethylformamide, Dimethyl Sulfoxide (DMSO), Dioxane, Ethanol, Ethyl Acetate, Heptane, Hexane, Methanol, Pentane, 1-Propanol, Isopropanol, Tetrahydrofuran (THF), Toluene, Trichloroethylene, Isooctane, Water, Xylene
Immiscible --
Miscibility Information and Solvent Miscibility Table

Tetrahydrofuran Hazard Statements

Hazard Statements H225-H319-H335-H351
Signal Word Danger
P210-P280-P304 + P340 + P312-P305 + P351 + P338-P337 + P313-P403 + P235


GHS Information

GHS Pictogram Statement
Flammable gases, category 1
Flammable aerosols, categories 1,2
Flammable liquids, categories 1,2,3
Flammable solids, categories 1,2
Self-reactive substances and mixtures, Types B,C,D,E,F
Pyrophoric liquids, category 1
Pyrophoric solids, category 1
Self-heating substances and mixtures, categories 1,2
Substances and mixtures, which in contact with water,
emit flammable gases, categories 1,2,3
Organic peroxides, Types B,C,D,E,F
Acute toxicity (oral, dermal, inhalation), category 4
Skin irritation, category 2
Eye irritation, category 2
Skin sensitisation, category 1
Specific Target Organ Toxicity – Single exposure, category 3
Respiratory sensitization, category 1
Germ cell mutagenicity, categories 1A,1B,2
Carcinogenicity, categories 1A,1B,2
Reproductive toxicity, categories 1A,1B,2
Specific Target Organ Toxicity – Single exposure, categories 1,2
Specific Target Organ Toxicity – Repeated exposure, categories 1,2
Aspiration Hazard, category 1


Tetrahydrofuran SDS Information

An SDS (Safety Data Sheet) is available for each tetrahydrofuran product. Start your search for an SDS.


Tetrahydrofuran Uses

Tetrahydrofuran (THF) has uses in several applications. As a chemical intermediate and industrial solvent. THF is a crucial material for the production of:

  • Printing inks for plastics,
  • PVC top coating,
  • PVC reactor cleaning,
  • PVC film casting,
  • and Cellophane coating.

THF is the solvent of choice in making polyvinyl chloride (PVC.), which is the plastic material used in indoor plumbing and sprinkler system pipes.

THF exposed to a strong acid induces polymerization. A form of a repeating network of THF molecules into what's called PTMEG.

PTMEG is the polymer used for making Spandex! 

Polymerization of THF

Polytetrahydrofuran (polyTHF), is an essential soft segment for the production of thermoplastic elastomers such as polyester and polyurethane.

THF reacts with cationic initiators to give polyTHF. Such reactions have been the subject of several papers.

Polymerization of THF proceeds via a cationic mechanism in which the nucleophilic THF monomer attacks an oxonium ion that is ring-opened.

The reaction can be catalyzed  in systems by

  • FSO3H, 
  • A mix of H2SO4 and SO3
  • A mix of HClO4 and acid anhydride, 
  • ClSO3H.

The following is the general reaction of this process:
Sigma Aldrich Tetrahydrofuran Cationic Polymerization

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