Benzofuran

Chemical properties

2,3-Benzofuran is a colorless, sweet-smelling, oily liquid made by processing coal into coal oil. It may also be formed during other uses of coal or oil. 2,3-Benzofuran is not used for any commercial purposes, but the part of the coal oil that contains 2,3-benzofuran is made into a plastic called coumarone-indene resin. This resin resists corrosion and is used to make paints and varnishes. The resin also provides water resistance and is used in coatings on paper products and fabrics. It is used as an adhesive in food containers and some asphalt fl oor tiles. The resin has been approved for use in food packages and as a coating on citrus fruits. We do not know how often the resin is used or whether any 2,3-benzofuran in the coating or packaging gets into the food. 2,3-Benzofuran may enter the air, water, and soil during its manufacture, use, or storage at hazardous waste sites. Breathing contaminated air or touching the chemical in the workplace is the source of human exposure.

The Uses of Benzofuran

manufacture of coumarone-indene resins.

The Uses of Benzofuran

As an intermediate in the polymerization of coumarone-indene resins found in various corrosion-resistant coatings such as paints and varnishes; in water-resistant coatings for paper products and fabrics; in adhesives for use in food containers

The Uses of Benzofuran

Benzo[b]furan is used in the manufacture of coumarone-indene resin. It has been used to make floor tiles and other products. It is also used as a coating on grapefruit, lemons, lirnes, oranges, tangelos and tangerines and in the production of COITosion-resistant paints and varnishes, in water-resistant coatings on paper products and fabrics and as adhesives in food containers.

Definition

A bicyclic ring compound derived from coal tar naphtha, the parent substance of coumarone-indene resins.

Synthesis Reference(s)

The Journal of Organic Chemistry, 44, p. 28, 1979 DOI: 10.1021/jo01315a008

General Description

Clear oily yellow liquid with an aromatic odor.

Air & Water Reactions

Highly flammable. May be sensitive to prolonged exposure to air. Very slightly water soluble.

Reactivity Profile

Benzofuran slowly polymerizes on standing. Benzofuran may be sensitive to prolonged exposure to air. Benzofuran is polymerized by H2SO4.

Hazard

Possible carcinogen.

Health Hazard

ACUTE/CHRONIC HAZARDS: When heated to decomposition Benzofuran emits acrid and irritating smoke and fumes.

Health Hazard

Rats and mice that ingested high levels of 2,3-benzofuran over a short time had liver and kidney damage. Those exposed over a long time to moderate levels had liver, kidney, lung, and stomach damage. In one study, the ability of animals to reproduce was not affected. We do not know if people will experience health effects similar to those seen in animals.

Fire Hazard

Benzofuran is combustible.

Carcinogenicity

Benzofuran was not mutagenic in bacterial assays but did cause chromosomal aberrations and sister chromatid exchanges in cultured rodent cells.

Purification Methods

Benzofuran is steam distilled, dissolved in Et2O, washed with 5% aqueous NaOH, saturated NaCl, dried (Na2SO4), evaporated and redistilled. UV: max 245, 275, 282nm (log 4.08, 3.45, 3.48). The picrate has m 102-103o. [Burgstahler & Worden Org Synth Coll Vol V 251 1973, NMR: Black & Heffernan Aust J Chem 18 353 1965, Beilstein 17/2 V 3.]