Tetrahydrofuran


Tetrahydrofuran
Tetrahydrofuran
Identifiers
CAS number 109-99-9 YesY
PubChem 8028
ChemSpider 7737 YesY
ChEBI CHEBI:26911 N
ChEMBL CHEMBL276521 YesY
RTECS number LU5950000
Jmol-3D images Image 1
Properties
Molecular formula C4H8O
Molar mass 72.11 g mol−1
Appearance colorless liquid
Density 0.8892 g/cm3 @ 20 °C, liquid
Melting point

−108.4 °C, 165 K, -163 °F

Boiling point

66 °C, 339 K, 151 °F

Solubility in water Miscible
Viscosity 0.48 cP at 25 °C
Structure
Molecular shape envelope
Dipole moment 1.63 D (gas)
Hazards
MSDS External MSDS
EU classification Flammable (F)
Irritant (Xi)
R-phrases R11, R19, R36/37
S-phrases S16, S29, S33
NFPA 704
NFPA 704.svg
3
2
0
Flash point −14 °C
Related compounds
Related heterocycles Furan
Pyrrolidine
Dioxane
Related compounds Diethyl ether
Supplementary data page
Structure and
properties
n, εr, etc.
Thermodynamic
data
Phase behaviour
Solid, liquid, gas
Spectral data UV, IR, NMR, MS
 N (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Tetrahydrofuran (THF) is a colorless, water-miscible organic liquid with low viscosity at standard temperature and pressure. This heterocyclic compound has the chemical formula (CH2)4O. As one of the most polar ethers with a wide liquid range, it is a useful solvent. Its main use, however, is as a precursor to polymers. THF has an odor similar to its chemical cousin, diethyl ether, but is a much less potent anesthetic than diethyl ether.

Contents

Production

About two hundred thousand tonnes of tetrahydrofuran are produced annually.[1] The most widely used industrial process involves the acid-catalyzed dehydration of 1,4-butanediol, akin to the production of diethyl ether from ethanol. The butanediol is derived from carbonylation of acetylene followed by hydrogenation. Du Pont developed a process for producing THF by oxidizing n-butane to crude maleic anhydride followed by catalytic hydrogenation.[2] A third major industrial route entails hydroformylation of allyl alcohol followed by hydrogenation to the butanediol.

THF can also be synthesized by catalytic hydrogenation of furan.[3][4] Where furan is derived from pentose, this method can involve renewable resources. Nevertheless, this route is not widely practiced.

Applications

THF can be polymerized by strong acids to give a linear polymer called poly(tetramethylene ether) glycol (PTMEG), CAS Registry Number [25190-06-1], also known as PTMO, polytetramethylene oxide. The primary use of this polymer is to make elastomeric polyurethane fibers like Spandex.[5]

As a solvent

The other main application of THF is as an industrial solvent for PVC and in varnishes.[6] It is an aprotic solvent with a dielectric constant of 7.6. It is a moderately polar solvent and can dissolve a wide range of nonpolar and polar chemical compounds.[7] THF is water-miscible, and can form solid clathrate hydrate structures with water at low temperatures.[8]

Laboratory use

Although a minor application, THF is a popular solvent in the laboratory when a moderately higher-boiling ethereal solvent is required and its water miscibility is not an issue. The oxygen center of ethers can coordinate to Lewis acids such as Li+, Mg2+, and boranes, forming adducts. Hence, like diethyl ether, THF can be used in hydroboration reactions to synthesize primary alcohols, and as a solvent for organometallic compounds such as organolithium and Grignard reagents.[9] Although similar to diethyl ether, THF is a stronger base.[10] Thus, while diethyl ether remains the solvent of choice for some reactions (e.g., Grignard reactions), THF fills that role in many others where strong coordination is desirable, and the precise properties of ethereal solvents such as these (alone and in mixtures and at various temperatures) allows for fine-tuning modern chemical reactions.

THF is often used in polymer science. For example, it can be used to dissolve polymers prior to determining its molecular mass using gel permeation chromatography. THF dissolves PVC as well and is the main ingredient in PVC adhesives. It can be used to liquefy old PVC cement, and is often used industrially to degrease metal parts.

2-MethylTHF

2-Methyltetrahydrofuran (2MeTHF) is a THF alternative that is being promoted as being more ecologically friendly.[11] Whereas 2-MeTHF is more expensive, it may provide for greater overall process economy. 2MeTHF has solvating properties that are intermediate between diethyl ether and THF, has limited water-miscibility, and forms an azeotrope with water on distillation. Its lower melting point makes it useful for lower temperature reactions, and its higher boiling point allows procedures under reflux at higher temperatures (relative to THF).

Precautions

THF is considered a relatively nontoxic solvent, with the median lethal dose (LD50) comparable to that for acetone. Reflecting its remarkable solvent properties, it penetrates the skin causing rapid dehydration. THF readily dissolves latex and is typically handled with nitrile or neoprene rubber gloves. It is highly flammable.

The greatest danger posed by THF follows from its tendency to form highly-explosive peroxides on storage in air. To minimize this problem, commercial samples of THF are often inhibited with BHT. THF should not be distilled to dryness, because the explosive peroxides concentrate in the residue.

See also

References

  1. ^ "Ethers, by Lawrence Karas and W. J. Piel". Kirk‑Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 2004. 
  2. ^ Merck Index of Chemicals and Drugs, 9th ed.
  3. ^ Morrison, Robert Thornton; Boyd, Robert Neilson: Organic Chemistry, 2nd ed., Allyn and Bacon 1972, p. 569
  4. ^ Donald Starr and R. M. Hixon (1943), "Tetrahydrofuran", Org. Synth., http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv2p0566 ; Coll. Vol. 2: 566 
  5. ^ "Polyethers, Tetrahydrofuran and Oxetane Polymers by Gerfried Pruckmayr, P. Dreyfuss, M. P. Dreyfuss". Kirk‑Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, Inc. 1996. 
  6. ^ Herbert Müller, "Tetrahydrofuran" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi:10.1002/14356007.a26_221
  7. ^ "Chemical Reactivity". Cem.msu.edu. http://www.cem.msu.edu/~reusch/VirtualText/enrgtop.htm#top4. Retrieved 2010-02-15. 
  8. ^ "FileAve.com". Gashydrate.fileave.com. http://gashydrate.fileave.com/NMR-MRI%20study%20of%20clathrate%20hydrate%20mechanisms.pdf. Retrieved 2010-02-15. 
  9. ^ Elschenbroich, C.; Salzer, A. ”Organometallics : A Concise Introduction” (2nd Ed) (1992) Wiley-VCH: Weinheim. ISBN 3-527-28165-7
  10. ^ E.g., B.L. Lucht, D.B. Collum "Lithium Hexamethyldisilazide: A View of Lithium Ion Solvation through a Glass-Bottom Boat" Accounts of Chemical Research, 1999, volume 32, 1035–1042 doi:10.1021/ar960300e, and references therein.
  11. ^ "Greener Solvent Alternatives - Brochure" (PDF). http://www.sigmaaldrich.com/etc/medialib/docs/Sigma/Brochure/greener_solvent_alternatives.Par.0001.File.tmp/greener_solvent_alternatives.pdf. Retrieved 2010-02-15. 

General reference

External links


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Look at other dictionaries:

  • Tetrahydrofuran — Strukturformel Allgemeines Name Tetrahydrofuran Andere Namen …   Deutsch Wikipedia

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  • tetrahydrofuran — oksolanas statusas T sritis chemija apibrėžtis Heterociklinis junginys. formulė Formulę žr. priede. santrumpa( os) THF priedas( ai) Grafinis formatas atitikmenys: angl. oxolane; tetrahydrofuran rus. оксолан; тетрагидрофуран ryšiai: sinonimas –… …   Chemijos terminų aiškinamasis žodynas

  • tetrahydrofuran — noun Etymology: tetrahydro + furan Date: circa 1943 a flammable liquid heterocyclic ether C4H8O that is derived from furan and used as a solvent and as an intermediate in organic synthesis …   New Collegiate Dictionary

  • tetrahydrofuran — /te treuh huy dreuh fyoor an/, n. Chem. a clear liquid, C4H8O, soluble in water and organic solvents, used as a solvent for resins, in polymerizations and as a chemical intermediate. [1940 45; TETRA + HYDRO 2 + FURAN] * * * …   Universalium

  • tetrahydrofuran — noun a heterocyclic ether having a five membered ring with four carbon atoms and one carbon; it is a colourless liquid with an ether like smell, and is used as a polar solvent …   Wiktionary

  • tetrahydrofuran — tet·ra·hy·dro·furan …   English syllables

  • tetrahydrofuran — “+ noun Etymology: International Scientific Vocabulary tetrahydr + furan : a flammable liquid heterocyclic ether C4H8O resembling ethyl ether that is made by hydrogenation of furan and is used as a solvent and as an intermediate in the… …   Useful english dictionary

  • Tetrahydrofuran (data page) — This page provides supplementary chemical data on tetrahydrofuran. Material Safety Data Sheet The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet (MSDS) for this… …   Wikipedia

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