2,4,5-Трихлорфенол

Химические свойства

White to pale brown solid in appearance; 2,4,5-Trichlorophenol also looks like small needles. It has a really strong odor that smells like phenol (a poisonous crystal-looking compound). This man-made substance is not found naturally in the environment.

Физические свойства

Colorless crystals or yellow to gray flakes with a strong, disinfectant or phenolic odor. At 40 °C, the average odor threshold concentration and the lowest concentration at which an odor were detected were 350 and 63 μg/L, respectively. At 25 °C, the lowest concentration at which a taste was detected was 100 μg/L (Young et al., 1996).

Использование

2,4,5-Trichlorophenol is used as a broad range pesticide against insects, fungi, vegetation and bacteria. It has become a common environmental contaminant and probable human carcinogen.

Определение

ChEBI: 2,4,5-trichlorophenol is a trichlorophenol carrying chloro groups at positions 2, 4 and 5.

Подготовка

2,4,5-Trichlorophenol is prepared indirectly, by the alkaline hydrolysis of 1,2,4,5-tetrachlorobenzene,because the direct chlorination of 2,5-dichlorophenol, difficult to achieve, proceeds with poor yield.

Общее описание

Colorless needles, gray flakes or off-white lumpy solid. Phenolic odor. Formerly used as a fungicide and bactericide.

Реакции воздуха и воды

Insoluble in water.

Профиль реактивности

2,4,5-Trichlorophenol is a weak monobasic acid. Incompatible with acid chlorides, acid anhydrides and oxidizing agents. Produces dioxin in alkaline medium at high temperatures

Пожароопасность

Literature sources indicate that 2,4,5-Trichlorophenol is nonflammable.

Профиль безопасности

Suspected carcinogen with experimental neoplastigenic data. Poison by intraperitoneal and intravenous routes. Moderately toxic by ingestion and subcutaneous routes. Experimental reproductive effects. Mutation data reported. When heated to decomposition it emits toxic fumes of Cland explodes. See also CHLOROPHENOLS.

Экологическая судьба

Biological. Chloroperoxidase, a fungal enzyme isolated from Caldariomyces fumago, chlorinated 2,4,5-trichlorophenol to give 2,3,4,6-tetrachlorophenol (Wannstedt et al., 1990).
Photolytic. When 2,4,5-trichlorophenol (100 μM) in an oxygenated, titanium dioxide (2 g/L) suspension was irradiated by sunlight (λ ≥340 nm), complete mineralization to carbon dioxide and water and chloride ions was observed (Barbeni et al., 1987a).
The following phototransformation half-lives were reported for 2,4,5-trichlorophenol in estuarine water exposed to sunlight and microbes: 1 h during winter; in distilled water: 0.6 and 1 h during summer and winter, respectively; in poisoned estuarine water: 14 and 24 h during summer and winter, respectively (Hwang et al., 1986).
A photooxidation rate constant of <3,000/M·sec was reported for the reaction of 2,4,5- trichlorophenol and ozone in water at a pH range of 1.2 to 1.5 (Hoigné and Bader, 1983). Chemical/Physical. 2,4,5-Trichlorophenol will not hydrolyze because it does not contain a hydrolyzable functional group (Kollig, 1993).
During the manufacture/synthesis of 2,4,5-T using alkalies at high temperatures, some TCDD may form (Worthing and Hance, 1991).

Методы очистки

Crystallise the phenol from EtOH or pet ether. [Beilstein 6 IV 962.]