Tetrahydrofuran
[CAS# 109-99-9]

Identification

• Classification: Organic raw materials >> Heterocyclic compound
• Name: Tetrahydrofuran
• Synonyms: 1,4-Epoxybutane; Butylene oxide; Cyclotetramethylene oxide; Furanidine; THF
• Molecular Formula: C₄H₈O
• Molecular Weight: 72.11
• CAS Registry Number: 109-99-9
• EC Number: 203-726-8
• SMILES: C1CCOC1

Properties

• Density: 0.886
• Melting point: -108.4 °C
• Boiling point: 66 °C
• Refractive index: 1.407
• Flash point: -21 °C
• Water solubility: miscible

Safety Data

• Hazard Symbols: GHS02;GHS07;GHS08 Danger
• Risk Statements: H225-H351-H335-H319
• Safety Statements: P203-P210-P233-P240-P241-P242-P243-P261-P264-P264+P265-P270-P271-P280-P301+P317-P303+P361+P353-P304+P340-P305+P351+P338-P318-P319-P330-P337+P317-P370+P378-P403+P233-P403+P235-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Flammable liquids	Flam. Liq.	2	H225
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2	H319
Carcinogenicity	Carc.	2	H351
Acute toxicity	Acute Tox.	4	H302
Specific target organ toxicity - single exposure	STOT SE	3	H336
Eye irritation	Eye Irrit.	2A	H319
Acute toxicity	Acute Tox.	2	H302
Specific target organ toxicity - single exposure	STOT SE	3	H370
Serious eye damage	Eye Dam.	1	H318
Skin irritation	Skin Irrit.	2	H315
Acute toxicity	Acute Tox.	4	H332
Flammable liquids	Flam. Liq.	3	H225
Acute toxicity	Acute Tox.	4	H312
Flammable liquids	Flam. Liq.	1	H224
Specific target organ toxicity - single exposure	STOT SE	2	H371
Skin corrosion	Skin Corr.	1B	H314

• Transport Information: UN 2056

Discovery and Applications

Tetrahydrofuran (THF) is a highly versatile, organic compound widely used as a solvent and chemical intermediate in various industries. Its discovery dates back to the early 20th century, where it was first isolated as a byproduct in the catalytic hydrogenation of furfural, a compound derived from agricultural waste. THF is a cyclic ether with a simple five-membered ring structure, and its chemical formula is (CH₂)₄O. The properties of THF, such as its low viscosity, ability to dissolve both polar and nonpolar substances, and relatively low boiling point (66°C), make it an ideal solvent in many industrial applications.

THF is primarily produced via the catalytic hydrogenation of furan or through the acid-catalyzed dehydration of 1,4-butanediol. The latter method is more commonly used today due to its higher efficiency and scalability. The commercial production of THF began in the mid-20th century as demand for versatile solvents and intermediates increased. Its ability to dissolve a wide range of organic compounds and polymers positioned THF as a critical solvent in various chemical processes, including polymer manufacturing, pharmaceuticals, and the production of fine chemicals.

One of the most significant applications of THF is in the production of polytetramethylene ether glycol (PTMEG), a key raw material for the synthesis of spandex fibers, polyurethanes, and elastomers. THF undergoes polymerization in the presence of strong acid catalysts to form PTMEG, which has exceptional elasticity and strength. This material is used extensively in the textile industry for producing elastic fibers, including spandex, which are valued for their stretchability and durability. THF’s role in this application has made it indispensable in the manufacture of flexible, high-performance fabrics and coatings.

THF is also widely used as a solvent in organic synthesis and the pharmaceutical industry. Its ability to dissolve a wide range of organic compounds makes it an excellent medium for Grignard reactions, metal hydride reductions, and other reactions involving organometallic reagents. These reactions often require solvents that are non-reactive toward highly reactive intermediates, and THF’s stability toward strong nucleophiles and bases makes it a suitable choice. Furthermore, its miscibility with water and many organic solvents enables THF to be used in multi-step synthetic processes. In pharmaceutical research, THF is employed as a solvent for drug discovery and the production of active pharmaceutical ingredients (APIs).

Another important application of THF is in the field of adhesives and coatings. THF is a preferred solvent in the formulation of polyurethane and vinyl adhesives due to its ability to dissolve polymers effectively. Its fast evaporation rate and ability to form clear, durable bonds make it suitable for use in coatings and adhesives for various materials, including plastics, metals, and textiles. In addition, THF is used as a solvent for polyvinyl chloride (PVC) in the production of flexible hoses, films, and sheets. Its ability to dissolve PVC efficiently and to produce uniform coatings has made it a key ingredient in the plastics industry.

In recent years, THF has found applications in the production of lithium-ion batteries. As a solvent in the electrolyte solutions of these batteries, THF plays a critical role in improving the efficiency of charge transfer between the anode and cathode. THF-based electrolytes enhance battery performance by promoting better ionic conductivity and stability. Its low viscosity and dielectric constant make THF particularly useful in this growing sector, where the demand for high-capacity energy storage systems continues to rise.

The handling of THF requires careful safety measures, as it is highly flammable and can form explosive peroxides upon prolonged exposure to air. Proper storage in tightly sealed containers and periodic testing for peroxide formation are necessary to minimize safety risks. Additionally, THF can pose health hazards if inhaled or absorbed through the skin, so protective equipment and proper ventilation are required when working with this compound.

The environmental impact of THF production and disposal has become an area of concern in recent years. As a volatile organic compound (VOC), THF can contribute to air pollution and pose environmental hazards if not managed correctly. Efforts to improve the sustainability of THF production, such as using renewable feedstocks or improving catalyst efficiency in production processes, are ongoing to reduce the environmental footprint of this important industrial chemical.

References

1998. Carcinogenesis Studies of Tetrahydrofuran Vapors in Rats and Mice. Toxicological sciences : an official journal of the Society of Toxicology.
DOI: 10.1006/toxs.1997.2399

2000. Preparation of Novel Synthons, Uniquely Functionalized Tetrahydrofuran and Tetrahydropyran Derivatives. Chemical and Pharmaceutical Bulletin.
DOI: 10.1248/cpb.48.1581

2024. Self-driving AMADAP laboratory: Accelerating the discovery and optimization of emerging perovskite photovoltaics. MRS Bulletin.
DOI: 10.1557/s43577-024-00816-4