Difference between revisions of "Furan"

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Latest revision as of 14:22, 11 January 2020

Furan
Names
IUPAC name
Furan
Preferred IUPAC name
1,4-Epoxybuta-1,3-diene
1-Oxacyclopenta-2,4-diene
Other names
1,4-Epoxy-1,3-butadiene
5-Oxacyclo-1,3-pentadiene
5-Oxacyclopenta-1,3-diene
Divinylene oxide
Furfuran
Oxa[5]annulene
Oxole
Properties
C4H4O
Molar mass 68.075 g/mol
Appearance Colorless volatile
Odor Ethereal, chloroform-like
Density 0.9731 g/cm3 (20 °C)
Melting point −85.6 °C (−122.1 °F; 187.6 K)
Boiling point 31.3 °C (88.3 °F; 304.4 K)
1 g/100 ml (25 °C)
Solubility Miscible with glacial acetic acid, acetone, benzene, chloroform, ethanol
Vapor pressure 600 mmHg at 25 °C
Thermochemistry
-34.45 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point −69 °C (−92 °F; 204 K)
Lethal dose or concentration (LD, LC):
200-2,000 mg/kg (rat, oral)
5.2 mg/kg (rat, IP)
7 mg/kg (mouse, IP)
Related compounds
Related compounds
Tetrahydrofuran
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Furan (C4H4O) is a heterocyclic organic compound, consisting of a five-membered aromatic ring with four carbon atoms and one oxygen. Chemical compounds containing such rings are also referred to as furans.

Properties

Chemical

Furan is aromatic because one of the lone pairs of electrons on the oxygen atom is delocalized into the ring, creating a 4n + 2 aromatic system similar to benzene. Because of the aromaticity, the molecule is flat and lacks discrete double bonds. Due to its aromaticity, furan's behavior is quite dissimilar to that of the more typical heterocyclic ethers such as tetrahydrofuran.

Physical

Furan is a colorless, flammable, highly volatile liquid with a boiling point slightly above room temperature. It is soluble in common organic solvents, including acetone, diethyl ether, ethanol and toluene, but is only slightly soluble in water. Its odor has been described as "strong, ethereal, chloroform-like".

Availability

Furan is sold by chemical suppliers.

Preparation

Furan can be obtained from furfural by oxidation to 2-furoic acid, followed by decarboxylation.[1]

Industrially, furan is manufactured by the palladium-catalyzed decarbonylation of furfural, or by the copper-catalyzed oxidation of 1,3-butadiene.

It can also be prepared directly by thermal decomposition of pentose-containing materials, and cellulosic solids, especially pine wood.

Projects

  • Make THF via hydrogenation of furan
  • Make pyrole

Handling

Safety

Furan is volatile and flammable. It is irritant, toxic and carcinogen. Exposure to furan at doses about 2000 times the projected level of human exposure from foods increases the risk of hepatocellular tumors in rats and mice and bile duct tumors in rats. Furan is therefore listed as a possible human carcinogen.

Furan is found in heat-treated commercial foods and is produced through thermal degradation of natural food constituents. It can be found in roasted coffee, instant coffee, and processed baby foods, though the amount is small.

Storage

In closed bottles, in well ventilated, dark fireproof cabinets.

Disposal

Should be mixed with a more flammable solvent and burned outside or in an incinerator.

References

  1. http://www.orgsyn.org/demo.aspx?prep=cv1p0274

Relevant Sciencemadness threads