2,4,5-Trichlorophenol

Chemical properties

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.

Physical properties

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).

The Uses of 2,4,5-Trichlorophenol

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.

Definition

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

Preparation

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.

General Description

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

Air & Water Reactions

Insoluble in water.

Reactivity Profile

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

Health Hazard

If your skin comes into contact with 2,4,5-trichlorophenol, it may burn the skin and produce redness and edema in humans. It also irritates the eyes, nose, pharynx, and lungs in humans.
Tests involving acute exposure of rats, mice, and guinea pigs have demonstrated 2,4,5-trichlorophenol to havemoderateacute toxicity by oral exposure.

Fire Hazard

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

Safety Profile

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.

Environmental Fate

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).

Purification Methods

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