1,2,3,4-Tetrachlorobenzene

WHITE CRYSTALLINE SOLID

Component of dielectric fluids, synthesis.

1,2,3,4-tetrachlorobenzene was used as a model compound to determine the chlorobenzenes (CBs) in soil samples. It was also used for rapid dechlorination of 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD).

ChEBI: A tetrachlorobenzene carrying chloro groups at positions 1, 2 , 3 and 4.

White to off-white crystals.

Insoluble in water.

Simple aromatic halogenated organic compounds, such as 1,2,3,4-Tetrachlorobenzene, are very unreactive. Reactivity generally decreases with increased degree of substitution of halogen for hydrogen atoms. Materials in this group may be incompatible with strong oxidizing and reducing agents. Also, they may be incompatible with many amines, nitrides, azo/diazo compounds, alkali metals, and epoxides.

ACUTE/CHRONIC HAZARDS: 1,2,3,4-Tetrachlorobenzene may cause irritation of the skin.

1,2,3,4-Tetrachlorobenzene is probably combustible.

Moderately toxic by ingestion. An experimental teratogen. Experimental reproductive effects. Irritant. Combustible liquid. When heated to decomposition it emits toxic fumes of Cl-. See also CHLORINATED HYDROCARBONS, AROMATIC.

Biological. A mixed culture of soil bacteria or a Pseudomonas sp. transformed 1,2,3,4- tetrachlorobenzene to 2,3,4,5-tetrachlorophenol (Ballschiter and Scholz, 1980). After incubation in sewage sludge for 32 d under anaerobic conditions, 1,2,3,4-tetrachlorobenzene did not biodegrade (Kirk et al., 1989). The half-life of 1,2,3,4-tetrachlorobenzene in an anaerobic enrichment culture was 26.4 h (Beurskens et al., 1993). Potrawfke et al. (1998) reported that a pure culture of Pseudomonas chlororaphis RW71 mineralized 1,2,3,4-tetrachlorobenzene as a sole source of carbon and energy. Intermediate biodegradation products identified were tetrachlorocatechol, tetrachloromuconic acid, 2,3,5-trichlorodienelactone, 2,3,5-trichloro-4-hydroxymuconic acid. In an enrichment culture derived from a contaminated site in Bayou d’Inde, LA, 1,2,4,5- tetrachlorobenzene underwent reductive dechlorination yielding 1,2,4-trichlorobenzene. The maximum dechlorination rate, based on the recommended Michaelis-Menten model, was 208 nM/d (Pavlostathis and Prytula, 2000).
Photolytic. Irradiation (λ ≥285 nm) of 1,2,3,4-tetrachlorobenzene (1.1–1.2 mM/L) in an acetonitrile-water mixture containing acetone (0.553 mM/L) as a sensitizer gave the following products (% yield): 1,2,3-trichlorobenzene (9.2), 1,2,4-trichlorobenzene (32.6), 1,3-dichlorobenzene (5.2), 1,4-dichlorobenzene (1.5), 2,2′,3,3′,4,4′,5-heptachlorobiphenyl (2.52), 2,2′,3,3′,4,5,6′- heptachlorobiphenyl (1.22), 10 hexachlorobiphenyls (3.50), five pentachlorobiphenyls (0.87), dichlorophenyl cyanide, two trichloroacetophenones, trichlorocyanophenol, (trichlorophenyl) acetonitriles, and 1-(trichlorophenyl)-2-propanone (Choudhry and Hutzinger, 1984). Without acetone, the identified photolysis products (% yield) included 1,2,3-trichlorobenzene (7.8), 1,2,4- trichlorobenzene (26.8), 1,2-dichlorobenzene (0.5), 1,3-dichlorobenzene (0.7), 1,4-dichloro-benzene (30.4), 1,2,3,5-tetrachlorobenzene (2.26), 1,2,4,5-tetrachlorobenzene (0.72), 2,2′,3,3′,4,4′,5- heptachlorobiphenyl (<0.01), and 2,2′,3,3′,4,5,6′-heptachlorobiphenyl (<0.01) (Choudhry and Hutzinger, 1984). The sunlight irradiation of 1,2,3,4-tetrachlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered Erlenmeyer flask for 56 d yielded 4,280 ppm heptachlorobiphenyl (Uyeta et al., 1976).

Soluble in acetic acid, ether, ligroin (Weast, 1986), and very soluble in many chlorinated solvents including chloroform, carbon tetrachloride, etc.

Crystallise it from EtOH. [Beilstein 5 H 204, 5 II 156, 5 III 550, 5 IV 667.]