Tetrahydrofuran

Molecular Structure of Tetrahydrofuran (CAS NO.109-99-9):

Molecular Formula: C₄H₈O
Molecular Weight: 72.1057
IUPAC Name: Oxolane
Synonyms of Tetrahydrofuran (CAS NO.109-99-9): 1,4-Epoxybutane ; AI3-07570 ; Agrisynth THF ; Butane, 1,4-epoxy- ; Butane, alpha,delta-oxide ; Butylene oxide ; CCRIS 6276 ; Cyclotetramethylene oxide ; Diethylene oxide ; EINECS 203-726-8 ; Furan, tetrahydro- ; Furanidine ; HSDB 125 ; Hydrofuran ; NCI-C60560 ; NSC 57858 ; Oxacyclopentane ; Oxolane ; RCRA waste number U213 ; THF ; Tetrahydrofuraan ; Tetrahydrofuraan [Dutch] ; Tetrahydrofuranne ; Tetrahydrofuranne [French] ; Tetraidrofurano ; Tetraidrofurano [Italian] ; Tetramethylene oxide ; RCRA waste no. U213 ; Tetrahydrofuran [UN2056] [Flammable liquid] ; UN2056
CAS NO: 109-99-9
Classification Code: Human Data ; Mutation data ; Reproductive Effect ; TSCA Flag T [Subject to the Section 4 test rule under TSCA] ; Tumor data
Melting Point: 33-36 °C 
Polar Surface Area: 9.23 Å²
Index of Refraction: 1.416
Molar Refractivity: 20.05 cm³
Molar Volume: 79.7 cm³
Surface Tension: 28.8 dyne/cm
Densityof Tetrahydrofuran (CAS NO.109-99-9): 0.904 g/cm³ 
Enthalpy of Vaporization: 29.81 kJ/mol
Boiling Point: 68.3 °C at 760 mmHg
Vapour Pressure: 152 mmHg at 25°C

The main application of Tetrahydrofuran (CAS NO.109-99-9) is as an industrial solvent for PVC and in varnishes.
Tetrahydrofuran(CAS NO.109-99-9) can be polymerized by strong acids to give a linear polymer called poly(tetramethylene ether) glycol (PTMEG), also known as PTMO, polytetramethylene oxide. The primary use of this polymer is to make elastomeric polyurethane fibers like Spandex. THF can be used in hydroboration reactions to synthesize primary alcohols, and as a solvent for organometallic compounds such as organolithium and Grignard reagents. It is often used in polymer science. It can be used to liquefy old PVC cement, and is often used industrially to degrease metal parts.

Tetrahydrofuran (CAS NO.109-99-9) can be manufactured from butane by using circulating solids technology in which butane is oxidized to maleic acid and thence to tetrahydrofuran (Fig. 1).

FIGURE 1 Manufacture of tetrahydrofuran from butane.

NTP Carcinogenesis Bioassay (feed); Clear Evidence: mouse, Some Evidence: rat NTPTR*    National Toxicology Program Technical Report Series. (Research Triangle Park, NC 27709) No. NTP-TR-475 ,1998. . Reported in EPA TSCA Inventory.

Hazard Codes of Tetrahydrofuran (CAS NO.109-99-9): Xi,F
Risk Statements: 36/37/38-19-11 
R36/37/38: Irritating to eyes, respiratory system and skin. 
R19: May form explosive peroxides. 
R11: Highly flammable.
Safety Statements: 26-36-33-29-16 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S36: Wear suitable protective clothing. 
S33: Take precautionary measures against static discharges. 
S29: Do not empty into drains. 
S16: Keep away from sources of ignition.
RIDADR: UN 2924 3/PG 2
WGK Germany: 1
RTECS: MD0916000
F: 3-10-23
HazardClass: 3
PackingGroup: II
HS Code: 29321100
Hazardous Substances Data 109-99-9(Hazardous Substances Data)
Moderately toxic by ingestion and intraperitoneal routes. Mildly toxic by inhalation. Human systemic effects by inhalation: general anesthesia. Mutation data reported. Irritant to eyes and mucous membranes. Narcotic in high concentrations. Reported as causing injury to liver and kidneys.
 Flammable liquid. A very dangerous fire hazard when exposed to heat, flames, oxidizers. Explosive in the form of vapor when exposed to heat or flame. In common with ethers, unstabilized tetrahydrofuran forms thermally explosive peroxides on exposure to air. Stored THF must always be tested for peroxide prior to distillation. Peroxides can be removed by treatment with strong ferrous sulfate solution made slightly acidic with sodium bisulfate. Caustic alkalies deplete the inhibitor in THF and may subsequently cause an explosive reaction. Explosive reaction with KOH, NaAlH₂, NaOH, sodium tetrahydroaluminate. Reacts with 2-aminophenol + potassium dioxide to form an explosive product. Reacts with lithium tetrahydroaluminate or borane to form explosive hydrogen gas. Violent reaction with metal halides (e.g., hafnium tetrachloride, titanium tetrachloride, zirconium tetrachloride). Vigorous reaction with bromine, calcium hydride + heat. Can react with oxidizing materials. To fight fire, use foam, dry chemical, CO₂. When heated to decomposition it emits acrid smoke and irritating fumes. See also 2-TETRAHYDROFURYL HYDROPEROXIDE.    

OSHA PEL: TWA 200 ppm; STEL 250 ppm
ACGIH TLV: TWA 200 ppm; STEL 250 ppm; BEI: 8 mg/L tetrahydrofuran in urine at end of shift
DFG MAK: 50 ppm (150 mg/m³)
DOT Classification:  3; Label: Flammable Liquid

  Tetrahydrofuran (CAS NO.109-99-9), its  occupational chemical analysis use NIOSH: Tetrahydrofuran, 1609.