1,2,4,5-Tetrachlorobenzene

white solid

1,2,4,5-Tetrachlorobenzene was used to study the environmental behavior of hexachlorobutadiene (HCBD).

Intermediate for herbicides and defoliants, insecticide, impregnant for moisture resistance, electrical insulation.

ChEBI: A tetrachlorobenzene carrying chloro groups at positions 1, 2, 4 and 5.

Biological. A mixed culture of soil bacteria or a Pseudomonas sp. transformed 1,2,4,5- tetrachlorobenzene to 2,3,5,6-tetrachlorophenol (Ballschiter and Scholz, 1980). After incubation in sewage sludge for 32 d under anaerobic conditions, 1,2,4,5-tetrachlorobenzene did not biodegrade (Kirk et al., 1989).
In an enrichment culture derived from a contaminated site in Bayou d’Inde, LA, 1,2,4,5- tetrachlorobenzene underwent reductive dechlorination to 1,2,4-trichlorobenzene. The maximum dechlorination rate, based on the recommended Michaelis-Menten model, was 5.5 nM/d (Pavlostathis and Prytula, 2000).
Photolytic. Irradiation (λ ≥285 nm) of 1,2,4,5-tetrachlorobenzene (1.1–1.2 mM/L) in an acetonitrile-water mixture containing acetone (0.553 mM) as a sensitizer gave the following products (% yield): 1,2,4-trichlorobenzene (25.3), 1,3-dichlorobenzene (8.1), 1,4-dichlorobenzene (3.6), 2,2′,3,4′,5,5′,6-heptachlorobiphenyl (4.19), four hexachlorobiphenyls (6.78), four pentachlorobiphenyls (2.33), one tetrachlorobiphenyl (0.32), 2,4,5-trichloroacetophenone, and (2,4,5- trichlorophenyl)acetonitrile (Choudhry and Hutzinger, 1984). Without acetone, the identified photolysis products (% yield) included 1,2,4-trichlorobenzene (27.7), 1,3-dichlorobenzene (0.3), 1,4-dichlorobenzene (8.5), pentachlorobenzene (trace), 1,2,3,4-tetrachlorobenzene (0.45), 1,2,3,5- tetrachlorobenzene (1.11), 2,2′,3,4′,5,5′,6-heptahlorobiphenyl (1.24), three hexachlorobiphenyls (1.19), and four pentachlorobiphenyls (0.56) (Choudhry and Hutzinger, 1984). The sunlight irradiation of 1,2,4,5-tetrachlorobenzene (20 g) in a 100-mL borosilicate glass-stoppered Erlenmeyer flask for 28 d yielded 26 ppm heptachlorobiphenyl (Uyeta et al., 1976).
Chemical/Physical. Based on an assumed base-mediated 1% disappearance after 16 d at 85 °C and pH 9.70 (pH 11.26 at °C), the hydrolysis half-life was estimated to be >900 yr (Ellington et al., 1988).

Crystallise it from EtOH, ether, *benzene, *benzene/EtOH or carbon disulfide. [Beilstein 5 IV 668.]

The current initial threshold screening level (ITSL) for 1,2,4,5-tetrachlorobenzene is 1 μg/m3 based on an annual averaging time.