Title: Furan
CAS Registry Number: 110-00-9
Additional Names: Furfuran; oxole; tetrole; divinylene oxide
Molecular Formula: C4H4O
Molecular Weight: 68.07
Percent Composition: C 70.58%, H 5.92%, O 23.50%
Literature References: Occurs in oils obtained by the distillation of rosin contg pine wood. Prepd by decarboxylation of 2-furancarboxylic acid: Wilson, Org. Synth. coll. vol. I (2nd ed., 1941), p 274. Has been prepd directly from furfural over hot soda-lime or by dropping furfural on a fused mixt of sodium and potassium hydroxides: Hurd et al., J. Am. Chem. Soc. 54, 2532 (1932). Toxicity data: Henderson, J. Pharmacol. Exp. Ther. 57, 394 (1936). Thermodynamic properties: G. B. Guthrie, Jr. et al., J. Am. Chem. Soc. 74, 4662 (1952).
Properties: Liquid. d419.4 0.9371. bp760 31.36°; bp758 32°. nD20 1.4216. Flash pt, closed cup: -32°F (-35°C). Absorption spectrum: Purvis, J. Chem. Soc. 97, 1648, 1655 (1910). Insol in water. Freely sol in alcohol and ether. Stable to alkalies; resinifies on evaporation or when in contact with mineral acids. LC (in air) in rats: 30400 ppm (Henderson).
Boiling point: bp760 31.36°; bp758 32°
Flash point: Flash pt, closed cup: -32°F (-35°C)
Index of refraction: nD20 1.4216
Density: d419.4 0.9371
Toxicity data: LC (in air) in rats: 30400 ppm (Henderson)
CAUTION: The vapors are anesthetic. Can be absorbed through skin. See: Toxicity of Industrial Metals, E. Browning (Appleton-Century-Crofts, New York, 2nd ed., 1969) p 698. This substance is reasonably anticipated to be a human carcinogen: Report on Carcinogens, Eleventh Edition (PB2005-104914, 2004) p III-127.
Use: In organic syntheses.
Furazabol Furazolidone Furazolium Chloride Furcellaran Furethidine

Full structural formula of furan Skeletal formula showing numbering convention
Ball-and-stick model Space-filling model
CAS number 110-00-9 YesY
PubChem 8029
ChemSpider 7738 YesY
KEGG C14275 YesY
ChEBI CHEBI:35559 YesY
Jmol-3D images Image 1
Molecular formula C4H4O
Molar mass 68.07 g mol−1
Appearance Colorless, volatile liquid
Density 0.936 g/mL
Melting point −85.6 °C; −122.1 °F; 187.6 K
Boiling point 31.3 °C; 88.3 °F; 304.4 K
MSDS Pennakem
R-phrases R26/27/28, R45
S-phrases S16, S37, S45, S28
NFPA 704
NFPA 704.svg
Flash point −69 °C; −92 °F; 204 K
Autoignition temperature 390 °C; 734 °F; 663 K
Explosive limits Lower:2.3%, upper:14.3% @ 20 °C
LD50 > 2 g/kg (rat)
Related compounds
Related heterocycles Pyrrole
Related compounds Tetrahydrofuran (THF)
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Furan is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen. The class of compounds containing such rings are also referred to as furans.

Furan is a colorless, flammable, highly volatile liquid with a boiling point close to room temperature. It is soluble in common organic solvents, including alcohol, ether and acetone, but is slightly soluble in water.[2] It is toxic and may be carcinogenic. Furan is used as a starting point to other specialty chemicals.[3]