1.2- Dibromoethane residues

Uptake of 1,2-dibromoethane readily occurs in rats following oral intubation (Botti et al. 1982 Nachtomi 1981 Plotnick et al. 1979 Van Bladeren et al. 1980). The presence of 1,2-dibromoethane residues in the kidney, liver, and spleen of rats following ingestion is also evidence of its absorption (Plotnick et al. 1979). It may be inferred that uptake from the gastrointestinal tract of rats is extensive, since 73% of a radiolabeled C-1,2-dibromoethane dose was excreted in the urine (Plotnick et al. 1979 Van Bladeren et al. 1980) and about 2% was excreted in the feces by 24- 48 hours (Plotnick et al. 1979). 

Dibromoethane residues in foods have decreased since the use of the compound as a fumigant was banned by EPA. For example. Daft (1989) reported finding 1,2-dibromoethane in only 2 of 549 samples of fatty and nonfatty foods analyzed for fumigant residues in a recent survey. 

To a stirred and refluxed suspension of 17 parts of 1,2-dibromoethane, 7.8 parts of sodium hydrogen carbonate and 50 parts of 2-propanol is added a mixture of 3.4 parts of dl-2-thio-1-phenyl-lmidazolidine, 9 parts of a 20% potassium hydroxide solution in 40 parts of 2-propanol over a period of about 1 hour. After the addition is complete, the whole is stirred and refluxed for an additional 3 hours. The reaction mixture is evaporated. To the residue are added 18 parts of a 15% potassium hydroxide solution. The whole is extracted with toluene. The extract is dried and evaporated. The oily residue is dissolved in acetone and gaseous hy-... 

Renal Effects. The clinical chemistry prior to death of two men who entered a pesticide tank that contained residues of 1,2-dibromoethane revealed acute renal failure (Letz et al. 1984). The exposure levels were not reported. 

Two fatal cases of occupational exposure to 1,2-dibromoethane were reported by Letz et al. (1984). A worker collapsed shortly after entering a pesticide storage tank containing residues of 1,2-dibromoethane he remained in the tank for 45 minutes. A supervisor attempting to rescue the worker also collapsed and was exposed for 20-30 minutes prior to rescue. Both men died 12 and 64 hours after collapse, respectively. The primary route of exposure was postulated to be dermal, with inhalation also playing a potentially important role. Neither worker had been wearing protective clothing or respirators. 

Erythema and blisters developed within 24 hours on the trunk and legs of a worker exposed to residues of 1,2-dibromoethane in a pesticide tank (Letz et al. 1984). This patient, immediately after rescue, complained of burning eyes, but ocular lesions did not develop. 

Neurological Effects. Depression, disorientation, and collapse have been reported in humans with acute exposure to toxic closes of 1,2-dibromoethane by oral (Saraswat et al. 1986) or dermal (Letz et al. 1984) routes. Residues of 1,2-dibromoethane were detected in the brain tissue of one fatality (Letz et al. 1984). The fact that the nervous system is at risk when humans are acutely exposed to lethal doses is supported by animal studies (Rowe et al. 1952). 

Dibromoethane was detected in samples of peanut butter and whiskey at a mean concentration of 7 ng/g (range 2-11 ng/g). Historical foodstuff residue levels have been reviewed by EPA (1983). 

Dumas T. 1962. Determination of 1,2-dibromoethane in air and as residue in fruits. J Agric Food Chem 10 476-477. 

Dry, clean magnesium turnings (1.22 g, 0.05 mol) are placed in a 250 ml three-necked flask, furnished with an atmosphere of argon, and dry ether (10 ml) is added. A mixture of 5-iodo-2-isopropylpentanonitrile (12.55 g, 0.05 mol) and ether (35 ml) is added dropwise. The reaction is initiated by the addition of a few drops of 1,2-dibromoethane. The mixture is stirred gently at 20-25° for 12-15 h, by which time the metal has reacted. Saturated aqueous ammonium chloride (20 ml) is added. The organic layer is separated and washed with sodium hyposulfite solution. The solvent is evaporated from the ether layer. A solution of oxalic acid (10 g) in water (60 ml) is added to the residue and heated under reflux for 4 h. Extraction with ether and distillation gives 2-isopropylcyclopentanone (4.54 g, 72%). 

A mixture consisting of (2.S )-/V-(4-hydroxy-5-mc(hoxy-2-ntirobcnzoyl)pyrrolidinc-2-carboxaldehyde diethylthioacetal (2 mmol), 1,2-dibromoethane (2.5 mmol), and K2C03 (3 mmol) dissolved in 40 ml acetone was refluxed 48 hours, then poured into water, and extracted with EtOAc. The solution was concentrated, the residue purified using chromatography with silica gel using EtOAc/hexane, 1 1, and the product isolated. 

A solution of lithium bis(trimethylsilyl)bismuthide-2 THF (25.3 g, 50 mmol) in pentane (100 ml) was added slowly to a cooled (-30°C) solution of 1,2-dibromoethane (4.7 g, 25 mmol) in the same solvent (100 ml). As the reaction proceeded, lithium bromide precipitated from a yellowish orange reaction mixture. Liberated ethylene gas (24.6 mmol) was collected into an inverted stand cylinder above water. After completion of the reaction, the precipitate was filtered off and washed successively with pentane. The volatiles were distilled off in vacuo at 20°C to leave a solid residue, which was recrystallized from pentane. The yield was 13.5 g (76%) [82ZN(B)91],... 

Intense room-temperature phosphorescence was obtained with 1,2 di-bromoethane (0.6 M) as heavy-atom perturber. The phenomenon was observed with 18 PNA [192] and 16 azaaromatics containing one or two heterocyclic nitrogens [193]. The formation of a three-component complex, CD/aromatic/dibromoethane, in which the aromatic and the heavy-atom perturber are organized in a small space, is believed to be responsible for the phosphorescence emission. It was found that, concomitant with phosphorescence emission, the fluorescence of the included aromatic was quenched. It should be noted that, for most of the aromatics examined, a residual phosphorescence emission was found also in air-equilibrated solutions. 

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