Tetrahydrofuran (THF) plays a vital role across various industries including semiconductors, coatings, adhesives, polymers, catalysts, printing inks, and magnetic tapes. As an important chemical raw material, THF is highly flammable. Improper storage or transportation could result in significant safety hazards or property damage. This article will help you understand the main applications and dangers of THF, along with correct storage practices to ensure safety.

1.   What is Tetrahydrofuran (THF)? Classification and Primary Applications

Chemical Name : Tetrahydrofuran (THF)
HS Code : 2932 1100 006
Chemical Formula : (CH₂)₄O
UN Classification : Class 3 Flammable Liquid
UN Number : 2056

Physical Properties:

• Boiling Point: 66°C
• Melting Point: -108.5°C
• Density: 0.889 g/cm³ (20°C)
• Solubility: Fully miscible with water and many organic solvents
• Volatility: High vapor pressure, evaporates easily

Chemical Properties:

• THF is generally chemically stable but can form explosive peroxides upon exposure to light or air.
• It acts as a weak Lewis base and can react with acids.
• Its cyclic structure allows it to undergo ring-opening reactions in the presence of acid or base catalysts, forming derivatives like 1,4-butanediol.

THF is a hydrogenated derivative of furan, classified as a heterocyclic ether and a saturated oxygen-containing compound. Synthesis methods include:

1. Natural gas → Formaldehyde → Succinic Dialdehyde → 1,4-Butanediol → THF
2. Pentose → Furan → THF (via hydrogenation)
3. Allyl alcohol → Butanediol → THF

Major Uses:

(1) Polymer Monomer

THF can be polymerized into Polytetramethylene Ether Glycol (PTMEG), a white, waxy solid. When reacted with isocyanates, it forms polyurethanes and spandex—used in elastomers, foaming agents, crosslinking agents, plastics, and sponges.

(2) Stable Solvent

THF has a relatively high boiling point and excellent solubility. It mixes with water in any proportion and is more chemically stable than diethyl ether, making it easier to control in temperature-sensitive reactions. It is widely used as a stabilizing solvent in the synthesis and storage of organometallic compounds, such as dimethylmercury, diethylmercury, ethylmagnesium bromide, trimethylaluminum, triethylaluminum, and triethylgallium. These highly reactive compounds are essential for producing thin film materials in the semiconductor industry. In addition, THF can dissolve plastics and latex, and is frequently used in laboratory settings, industrial processes, and polymer material applications to fine-tune conductivity and maintain solution stability.

(3) Derivatives

Tetrahydrofuran (THF) can be further processed into a variety of derivatives with wide-ranging applications:

• Borane–THF Complex:
  This is a commonly used reducing agent, capable of converting amino acids into amino alcohols. It also serves as an intermediate in the synthesis of other borane-based compounds. Due to its high flammability and extreme sensitivity to water, air, and light, it must be stored in sealed, opaque containers filled with inert gas. This complex is typically synthesized by the direct reaction of THF with diborane, or by reacting iodine and sodium borohydride in THF.
• Methyl Tetrahydrofuran (Methyl-THF):
  A methylated derivative of THF that is insoluble in water and has a higher boiling point than THF. It is an ideal alternative solvent in high-temperature reactions and industrial processes, offering improved performance and stability under thermal conditions.
• Tetrahydrofurfuryl Alcohol (THFA):
  A hydroxymethylated derivative of THF, used as a solvent for resins and oils, as well as a decolorizing and deodorizing agent in pharmaceutical applications. It also serves as an intermediate in the production of herbicides and insecticides.
• THF Coordination Compounds:
  THF reacts with metals or metal halide salts to form coordination compounds that release significant heat during synthesis. These reactions are safer when carried out in aliphatic solvents like n-hexane or dichloromethane. These compounds are widely used in post-processing for metal-organic framework (MOF) materials. Common examples include:

• TiCl₄(THF)₂
• MgCl₂(THF)₂
• [Ti(MgCl)₂(THF)]₂
• Ti₂(OOCH)₄MgCl₃(THF)₂
• TiCl₃(THF)₃
• [TiCl₂(THF)₄][SnCl₅(THF)]

2.   Understanding the Risks of THF

THF can catch fire or explode when it reacts with certain materials, emitting hazardous fumes. It poses health risks such as :

• Inhalation: Causes headache, irritation in the nasal and throat passages, central nervous system depression, lowered blood pressure, and potential shock.
• Eye Contact: Can lead to corneal opacity, swelling, redness, and in severe cases, blindness.

Immediate medical attention is required in case of exposure.

3.   How to Store THF Safely: Key Guidelines

(1) Cool, Well-Ventilated Storage Area

Store THF in sealed, opaque containers in a cool, ventilated space. Avoid exposure to light and air to prevent the formation of explosive peroxides. Keep THF away from oxidizers, peroxides, halogens (especially bromine), alkali metals, and their hydroxides to avoid combustion, heat generation, or explosions.

(2) Sealed Packaging

Without inhibitors, THF can polymerize upon exposure to air and light, leading to pressure buildup and possible explosion. Since it’s highly volatile and harmful when inhaled, THF should always be sealed and ideally contain stabilizers.

(3) Hazard Labeling

Containers should display appropriate hazard labels to inform workers of the risks and safety measures required. In case of emergencies during transport, labels help guide proper response procedures.

Further Reading : What Are Dangerous Goods? A Quick Guide to Hazard Classification and Transport Regulations

(4) Personal Protective Equipment (PPE)

Workers handling THF must wear gloves, protective clothing, goggles, and respirators. Proper training is mandatory.

(5) Use Non-Sparking Tools

THF is extremely flammable and reactive to open flames, high temperatures, static electricity, and light. Only non-sparking tools—preferably plastic—should be used; metal tools are prohibited. Ensure the environment is free of ignition sources.

(6) Emergency Equipment

Emergency response equipment must be available near storage areas. MSDS documents should be prominently posted for quick access during incidents.

Further Reading : How to Understand the MSDS (Material Safety Data Sheet) and Key Details to Watch For

Published Date : January 7, 2025