2,6-Dinitrotoluene

Chemical Properties

2,6-Dinitrotoluene is one of the six dinitrotoluene isomers. Dinitrotoluene (DNT) or Dinitro is an explosive with the formula C6H3(CH3)(NO2)2. At room temperature it is a pale yellow to orange crystalline solid. It is a high explosive and one of the precursors for trinitrotoluene (TNT), which is synthesized through three separate nitrations of toluene. The first product is mononitrotoluene, DNT is the second, and TNT is the third and final product.

Physical properties

Pale yellow, orange, brown or reddish rhombic crystals. Odor threshold concentration in water is 100 ppb (quoted, Keith and Walters, 1992).

Uses

Organic synthesis; propellant additive; manufacture of explosives; intermediate in the manufacture of polyurethanes.

Uses

2,6-Dinitrotoluene is used primarily, along with the other isomers, in producing toluene diisocyanate; production of the diisocyanate ranges from 100 million to almost a billion pounds each year.

Definition

ChEBI: 2,6-dinitrotoluene is a dinitrotoluene carrying nitro substituents at positions 2 and 6. It has a role as a genotoxin.

Preparation

2,6-Dinitrotoluene is synthesized from o-nitrotoluene by nitration with mixed acid.

General Description

Yellow to red solid or heated liquid with a slight odor. Solidifies in cool water. Solid and liquid sink in water.

Air & Water Reactions

Mixes slowly with water. Insoluble in water.

Reactivity Profile

2,6-Dinitrotoluene is sensitive to heat. 2,6-Dinitrotoluene may explode when exposed to heat or flame. 2,6-Dinitrotoluene can be detonated only by a very strong initiator. 2,6-Dinitrotoluene is incompatible with strong oxidizers. 2,6-Dinitrotoluene is also incompatible with caustics and metals such as tin and zinc. 2,6-Dinitrotoluene may react with reducing agents. 2,6-Dinitrotoluene will attack some forms of plastics, rubber and coatings.

Health Hazard

INHALATION, INGESTION OR SKIN ABSORPTION: Headache, weakness, nausea or dizziness, cyanosis, drowsiness, shortness of breath and collapse. Can burn eyes and skin.

Safety Profile

Poison by ingestion. A skin irritant. Questionable carcinogen with experimental tumorigenic data. Mutation data reported. When heated to decomposition it emits toxic fumes of NOx. See also 2,4-DINITROTOLUENE

Environmental Fate

Biological. When 2,6-dinitrotoluene was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum, significant biodegradation with gradual acclimation was followed by deadaptive process in subsequent subcultures. At a concentration of 5 mg/L, 82, 55, 47, and 29% losses were observed after 7, 14, 21, and 28-d incubation periods, respectively. At a concentration of 10 mg/L, only 57, 49, 35, and 13% were observed after 7, 14, 21, and 28-d incubation periods, respectively (Tabak et al., 1981). Under anaerobic and aerobic conditions, a sewage inoculum degraded 2,6-dinitrotoluene to aminonitrotoluene (Hallas and Alexander, 1983).
Photolytic. Simmons and Zepp (1986) estimated the photolytic half-life of 2,6-dinitrotoluene in surface water to range from 2 to 17 h.
Low et al. (1991) reported that the nitro-containing compounds (e.g., 2,4-dinitrophenol) undergo degradation by UV light in the presence of titanium dioxide yielding ammonium, carbonate, and nitrate ions. By analogy, 2,6-dinitrotoluene should degrade forming identical ions.
Chemical/Physical. 2,6-Dinitrotoluene will not hydrolyze (Kollig, 1993).
At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities were 145, 70, 33, and 16 mg/g, respectively (Dobbs and Cohen, 1980).

Metabolic pathway

2-Amino-6-nitrotoluene, 2,6-dinitrobenzyl alcohol, 2- amino-6-nitrobenzyl alcohol, and the conjugates of the latter two alcohols are detected in the urine of male Wistar rats as metabolites of 2,6-dinitrotoluene (2,6- DNT). In addition to the metabolites identified in the urine, 2,6-dinitrobenzaldehyde is detected in the rat bile. Incubation of 2,6-DNT with a hepatic microsomal preparation gives 2,6-dinitrobenzyl alcohol. Incubation of benzyl alcohol with a microsomal plus cytosol preparation gives 2,6-dinitrobenzaldehyde, and incubation of 2,6-dinitrobenzaldehyde with cytosol preparations gives 2,6-dinitrobenzyl alcohol and 2,6- dinitrobenzoic acid.

Purification Methods

Crystallise it from acetone. EXPLOSIVE when dry.[Beilstein 5 III 761, 5 IV 866.]