TETRAHYDROFURAN

Tetrahydrofuran
(THF, oxacyclopentane, tetramethylene oxide)
CAS 109-99-9

(CH₂ )₄O

Colorless liquid
bp 66 °C, mp -108 °C
Miscible with water

Ethereal, detectable at 2 to 50 ppm

2.5 (air = 1.0)

160 mmHg at 25 °C

-14 °C

321 °C

LD₅₀ oral (rat) 2880 mg/kg

LC₅₀ inhal (rat) 21,000 ppm (3 h)

PEL (OSHA) 200 ppm (590 mg/m³)

TLV-TWA (ACGIH) 200 ppm (590 mg/m³)

STEL (ACGIH) 250 ppm (737 mg/m³)

Highly flammable; forms sensitive peroxides on exposure to air, which may explode on concentration by distillation or drying.

The acute toxicity of THF by inhalation and ingestion is low. Liquid THF is a severe eye irritant and a mild skin irritant, but is not a skin sensitizer. At vapor levels of 100 to 200 ppm, THF irritates the eyes and upper respiratory tract. At high concentrations (25,000 ppm), THF vapor can produce anesthetic effects. Since the odor threshold for THF is well below the permissible exposure limit, this substance is regarded as having good warning properties.

Limited animal testing indicates that THF is not carcinogenic and shows developmental effects only at exposure levels producing other toxic effects in adult animals. Bacterial and mammalian cell culture studies demonstrate no mutagenic activity with THF.

THF is extremely flammable (NFPA rating = 3), and its vapor can travel a considerable distance to an ignition source and "flash back." A 5% solution of THF in water is flammable. THF vapor forms explosive mixtures with air at concentrations of 2 to 12% (by volume). Carbon dioxide or dry chemical extinguishers should be used for THF fires.

THF can form shock- and heat-sensitive peroxides, which may explode on concentration by distillation or evaporation. Always test samples of THF for the presence of peroxides before distilling or allowing to evaporate. THF should never be distilled to dryness.

THF can form potentially explosive peroxides upon long exposure to air. THF may react violently with strong oxidizers and reacts vigorously with bromine and titanium tetrachloride. Polymerization can occur in the presence of cationic initiators such as certain Lewis acids and strong protic acids.

Storage and Handling

THF should be handled in the laboratory using the "basic prudent practices" described in Chapter 5.C, supplemented by the additional precautions for dealing with extremely flammable substances (Chapter 5.F). In particular, THF should be used only in areas free of ignition sources, and quantities greater than 1 liter should be stored in tightly sealed metal containers in areas separate from oxidizers. Containers of THF should be dated when opened and tested periodically for the presence of peroxides.

In the event of skin contact, immediately wash with soap and water and remove contaminated clothing. In case of eye contact, promptly wash with copious amounts of water for 15 min (lifting upper and lower lids occasionally) and obtain medical attention. If THF is ingested, obtain medical attention immediately. If large amounts of this compound are inhaled, move the person to fresh air and seek medical attention at once.

In the event of a spill, remove all ignition sources, soak up the THF with a spill pillow or absorbent material, place in an appropriate container, and dispose of properly. Respiratory protection may be necessary in the event of a large spill or release in a confined area.

Excess THF and waste material containing this substance should be placed in an appropriate container, clearly labeled, and handled according to your institution's waste disposal guidelines.

The information in this LCSS has been compiled by a committee of the National Research Council from literature sources and Material Safety Data Sheets and is believed to be accurate as of July 1994. This summary is intended for use by trained laboratory personnel in conjunction with the NRC report Prudent Practices in the Laboratory: Handling and Disposal of Chemicals. This LCSS presents a concise summary of safety information that should be adequate for most laboratory uses of the title substance, but in some cases it may be advisable to consult more comprehensive references. This information should not be used as a guide to the nonlaboratory use of this chemical.

Copyright 1995 National Academy of Sciences. All rights reserved.