Dibenzofuran

Description

Dioxins and furans, two well-known environmental pollutants, are extremely toxic to humans and many other species. Dibenzofurans are released into the air from combustion sources, and are listed as pollutants of concern due to its persistence in the environment, potential to bioaccumulate, and toxicity to humans and the environment. These compounds, when adsorbed on soils or other substrates, are highly persistent under normal environmental conditions. The Office of Environmental Health Hazard Assessment reviews risk assessments submitted under the Air Toxics ‘Hot Spots’ Program (AB 2588) in which chlorinated dibenzo-p-dioxins and dibenzofurans are listed. Chlorinated dibenzofurans were calculated as total 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalents in the AB 2588 risk assessments. Dibenzofuran is cited in the Clean Air Act 1990 Amendments – Hazardous Air Pollutants as a volatile hazardous air pollutant of potential concern. The Superfund Amendment Reauthorization Act Section 110 placed dibenzofuran on the revised Agency for Toxic Substances and Disease Registry priority list of hazardous substances to be the subject of a toxicological profile. Dibenzofuran is also listed in the Massachusetts Substance List for Right to Know Law, the New Jersey Department of Health Hazard Right to Know Program Hazardous Substance List, the Pennsylvania Department of Labor and Industry Hazardous Substance List, and the California’s Air Toxics ‘Hot Spots’ List (Assembly Bill 2588).

Chemical properties

white to light yellow crystal powde

Chemical properties

Dibenzofuran is a white crystalline powder.

Physical properties

Colorless crystals having a creosote-like odor. The least detectable odor threshold concentration in water at 60 °C was 2 μg/L (Alexander et al., 1982).

The Uses of Dibenzofuran

Dibenzofuran is an industrial chemical or by-product, and is used as an insecticide, in the production of PVC, industrial bleaching and incineration.

The Uses of Dibenzofuran

Research chemical. Derived from industrial and experimental coal gasification operations where the maximum concentration detected in coal gas tar streams was 12 mg/m³ (Cleland, 1981).

The Uses of Dibenzofuran

Applications for GC (Gas Chromatography) and LC (Liquid Chromatography) Analysis. Dibenzofuran as the model substrate in culture procedures.

Definition

ChEBI: A mancude organic heterotricyclic parent that consists of a furan ring flanked by two benzene rings ortho-fused across the 2,3- and 4,5-positions.

Synthesis Reference(s)

Journal of the American Chemical Society, 81, p. 487, 1959 DOI: 10.1021/ja01511a056
The Journal of Organic Chemistry, 40, p. 1365, 1975 DOI: 10.1021/jo00897a048

General Description

Colorless white crystalline solid.

Air & Water Reactions

Insoluble in water.

Reactivity Profile

Dibenzofuran is sensitive to prolonged exposure to light .

Fire Hazard

Flash point data for Dibenzofuran are not available. Dibenzofuran is probably combustible.

Potential Exposure

This material is used as an insecticide and in organic synthesis to make other chemicals. It is derived from coal tar creosote.

First aid

Skin Contact: Flood all areas of body thathave contacted the substance with water. Do not wait toremove contaminated clothing; do it under the water stream.Use soap to help assure removal. Isolate contaminatedclothing when removed to prevent contact by others. EyeContact: Remove any contact lenses at once. Flush eyeswell with copious quantities of water or normal saline for atleast 2030 min. Seek medical attention. Inhalation: Leavecontaminated area immediately; breathe fresh air. Properrespiratory protection must be supplied to any rescuers. Ifcoughing, difficult breathing, or any other symptoms develop, seek medical attention at once, even if symptomsdevelop many hours after exposure. Ingestion: If convulsions are not present, give a glass or two of water or milk todilute the substance. Assure that the person’s airway isunobstructed and contact a hospital or poison center immediately for advice on whether or not to induce vomiting.

Source

Based on laboratory analysis of 7 coal tar samples, dibenzofuran concentrations ranged from 170 to 4,000 ppm (EPRI, 1990).
Schauer et al. (1999) reported dibenzofuran in diesel fuel at a concentration of 29 μg/g and in a diesel-powered medium-duty truck exhaust at an emission rate of 28.7 μg/km.
Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 5.5 and 42.2 μg/km, respectively (Schauer et al., 2002).

Environmental Fate

Biological. Dibenzofuran was oxidized by salicylate-induced cells of Pseudomonas sp. strain 9816/11 and isopropyl-β-D-thiogalactopyranoside-induced cells of Escherichia coli JM109(DE3) (pDTG141) to (1R,2S)-cis-1,2-dihydroxy-1,2-dihydrodibenzofuran (60–70% yield) and (3S,4R)- cis-3,4-dihydroxy-3,4-dihydrodibenzofuran (30–40% yield) (Resnick and Gibson, 1996).
Soil. The estimated half-lives of dibenzofuran in soil under aerobic and anaerobic conditions were 7 to 28 and 28 to 112 d, respectively (Lee et al., 1984).
Groundwater. Based on aerobic acclimated and unacclimated groundwater die away test data, the estimated half-life of dibenzofuran in groundwater ranged from 8.54 to 34.9 d (Lee et al., 1984).
Photolytic. The estimated half-life for the reaction of dibenzofuran with OH radicals in the atmosphere ranged from 1.9 to 19 h (Atkinson, 1987).
Chemical/Physical. It was suggested that the chlorination of dibenzofuran in tap water accounted for the presence of chlorodibenzofuran (Shiraishi et al., 1985).
Dibenzofuran will not hydrolyze because it has no hydrolyzable functional group (Kollig, 1995).

storage

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location.

Shipping

UN3077 Environmentally hazardous substances, solid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Purification Methods

Dissolve dibenzofuran in diethyl ether, then shake it with two portions of aqueous NaOH (2M), wash it with water, separate and dry (MgSO4) it. After evaporating the ether, dibenzofuran is crystallised from aqueous 80% EtOH and then dried under vacuum. [Cass et al. J Chem Soc 1406 1958.] High purity material is obtained by zone refining. [Beilstein 17 V 234.]

Toxicity evaluation

Dibenzofuran is a white crystalline solid. It is not soluble in water, but soluble in organic solvents like alcohol, acetone, ether, benzene, and acetic acid. Its boiling point is 287°C, melting point is 86°C, and specific gravity is 1.0886. Its octanol/ water partition coefficient is 4.12.
Presence of dibenzofuran in coal tar, oil and its uses may result in its release to the environment through various waste streams. It has very low to no mobility in soil and degrades in soil. It dissolves in water as well as volatilizes. As a gas phase in the atmosphere, it reacts with photochemically produced hydroxy radicals. It is biodegraded rapidly at contaminated sites by the microorganisms present; otherwise its biodegradation is relatively slow. It adsorbs very strongly to sediment and particulate matter in the water column. It has a potential to bioconcentrate in aquatic organisms.

Incompatibilities

This material is used as an insecticide and in organic synthesis to make other chemicals. It is derived from coal tar creosote.

Waste Disposal

In accordance with 40CFR165, follow recommendations for the disposal of pesticides and pesticide containers. Must be disposed prop- erly by following package label directions or by contacting your local or federal environmental control agency, or by contacting your regional EPA office.