Tetrahydrofuran (THF) is a clear, colorless, low-viscosity liquid with an ether-like odor. THF exhibits high volatility and an extremely low freezing point. At 20°C, THF is completely miscible with water.
THF is a versatile solvent with numerous industrial applications. Due to its tendency to form peroxides on storage, THF is inhibited with BHT.
THF is produced by the cyclodehydration of 1,4-BDO. Lyondell produces 1,4-BDO in a proprietary process starting with allyl alcohol.
Benefits and Applications
Polytetramethylene Ether Glycol (PTMEG)
THF is polymerized under strong acidic conditions to form PTMEG which is used extensively to manufacture urethane elastomers and fibers. PTMEG provides exceptional flexibility and elasticity to such products. In particular, PTMEG based urethanes are noted for their good flex properties at low temperature and their hydrolytic resistance.
Solvents are needed to dissolve the raw binder polymers and to provide a fluid medium for the pigment dispersion in the magnetic tape paint. THF, with its high purity, excellent solvency power and favorable conductivity value, is fast becoming the solvent of choice.
THF solvents can be used to join rigid plastic pipe and in compounded cements for leather, plastic sheet film extrusions and for molded plastic parts assemblies. The combined advantages of rapid solvent activity, minimum gelation and lower relative viscosities for resin solutions, makes THF an attractive solvent choice.
THF-PVC formulations meet NSF standards. THF solvent cements can be formulated with additional solvents and inorganic fillers to control set time. THF can also function as a PVC-type cleaner before joint formation.
Vinyl Films and Cellophane
THF is a superb solvent for many chlorinated resins which find utility in film formation applications such as vinyl topcoating, cast vinyl films, and coated cellophane. Such applications rely on the ability of THF to solvate the polymeric resins without excessive viscosity build up. In addition, the high volatility of THF is essential in these applications because of the need to remove the solvent completely with minimal energy input.
Pharmaceutical Solvent Applications
THF is frequently utilized as a solvent in many pharmaceutical synthetic procedures because of its broad solvency for polar and non-polar compounds. THF is particularly capable of dissolving many ionic species and organometallics which are commonly used in specialty syntheses. In many cases, THF makes higher yields and faster reaction rates possible. In addition, THF's high volatility and very high purity facilitate solvent removal and recovery without leaving residues in the desired product.
THF is stable under very strongly basic conditions and is therefore the choice for numerous specialty syntheses which involve complex catalysts and Grignard reagents. Also, THF is a preferred solvent for anionic polymerization.
Miscellaneous Solvent Applications
THF is used in very large quantities in research institutions worldwide as a solvent for numerous chromatographic techniques such as Gel Phase Chromatography. Its broad solvency capabilities are consistently reliable. Other examples of its utilization as a solvent are:
- Natural Products
- Industrial Resins
- Polyurethane Coatings
- Printing Inks
The current Occupational Safety and Health Administration (OSHA) (US) exposure limits for tetrahydrofuran are two-hundred (200) parts of tetrahydrofuran per million parts of air (ppm) averaged over an eight (8) hour work shift and two-hundred fifty (250) ppm over a period of 15 minutes. Tetrahydrofuran has a ether-like odor. The vapor of tetrahydrofuran is highly irritating to the eyes of human subjects. Inhalation of tetrahydrofuran vapors may cause central nervous system depression. THF has an odor threshold in the range of 2 to 50 ppm so that it is readily detectable before its exposure limits are reached.
The intent of this information is to inform personnel who handle or may be exposed to tetrahydrofuran of the properties and hazards associated with the compound. The purpose is not to present all the data, rather, it is to present pertinent information, data and references in a summary form.
U.S. Superfund Amendments and Reauthorization Act of 1986 (SARA), Title III:
Section 311/312 Hazard Categories: None known to apply.
Section 313 Hazard Category: No chemicals in this product exceed the de minimus reporting level established by SARA Title III, Section 313 and 40 CFR 372.
U.S. Toxic Substances Control Act (TSCA):
All components of this product are listed on the TSCA inventory.
U.S. Comprehensive Environmental Response, Compensation and Liability Act (CERCLA):
This product contains the following chemicals subject to the reporting requirements of CERCLA: Tetrahydrofuran, 1000# / 454 kg.
California (U.S.) Safe Drinking Water and Toxic Enforcement Act of 1986 -- Proposition 65:
Based on information currently available, this product is not known to contain any chemicals currently listed as carcinogens or reproductive toxins under California Proposition 65 at levels which would be subject to this proposition. If you reformulate or further process this product you should further evaluate the resultant product based upon such reformulation or processing, as well as upon its final composition and use.
Storage and Handling
THF has a flammable DOT hazard class. As a result, heat, sparks, open flames, open containers and poor ventilation are conditions to be avoided. Materials to avoid include oxidizing agents and strong acids and bases. Care should be taken to store THF under cool, dry conditions due to its volatile and flammable nature. While THF as supplied contains an inhibitor, heat sensitive peroxides can form if stored for long periods of time. Explosions have been known to occur when uninhibited THF was heated.
For more safety/health information, please refer to Lyondell's MSDS or specific Product Storage & Handling Guide.