1,2-Dibromoethane, also known as ethylene dibromide (EDB), is an organobromine compound with the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

. Although trace amounts occur naturally in the

ocean The ocean (also the sea or the world ocean) is the body of salt water that covers approximately 70.8% of the surface of Earth and contains 97% of Earth's water. An ocean can also refer to any of the large bodies of water into which the wor ...

, where it is formed probably by

algae Algae (; singular alga ) is an informal term for a large and diverse group of photosynthetic eukaryotic organisms. It is a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from unicellular micr ...

and

kelp Kelps are large brown algae seaweeds that make up the order Laminariales. There are about 30 different genera. Despite its appearance, kelp is not a plant - it is a heterokont, a completely unrelated group of organisms. Kelp grows in "underwa ...

, it is mainly synthetic. It is a dense colorless liquid with a faint sweet odor, detectable at 10 ppm, is a widely used and sometimes-controversial fumigant. The combustion of 1,2-dibromoethane produces

hydrogen bromide Hydrogen bromide is the inorganic compound with the formula . It is a hydrogen halide consisting of hydrogen and bromine. A colorless gas, it dissolves in water, forming hydrobromic acid, which is saturated at 68.85% HBr by weight at room tem ...

gas that is significantly corrosive.

Preparation and use

It is produced by the reaction of

ethylene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene ...

gas with

bromine Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table ( halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simi ...

, in a classic halogen addition reaction: :CH=CH + Br → BrCH–CHBr Historically, 1,2-dibromoethane was used as a component in anti-knock additives in leaded fuels. It reacts with lead residues to generate volatile lead bromides, thereby preventing fouling of the engine with lead deposits.

Pesticide

It has been used as a

pesticide Pesticides are substances that are meant to control pests. This includes herbicide, insecticide, nematicide, molluscicide, piscicide, avicide, rodenticide, bactericide, insect repellent, animal repellent, microbicide, fungicide, and ...

soil Soil, also commonly referred to as earth or dirt, is a mixture of organic matter, minerals, gases, liquids, and organisms that together support life. Some scientific definitions distinguish ''dirt'' from ''soil'' by restricting the former ...

and on various crops. The applications were initiated after the forced retirement of 1,2-dibromo-3-chloropropane (DBCP). Most of these uses have been stopped in the U.S. It continues to be used as a fumigant for treatment of logs for

termite Termites are small insects that live in colonies and have distinct castes ( eusocial) and feed on wood or other dead plant matter. Termites comprise the infraorder Isoptera, or alternatively the epifamily Termitoidae, within the order Blat ...

s and

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

s, for control of

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

s in beehives.

Reagent

1,2-Dibromoethane has wider applications in the preparation of other organic compounds including those carrying modified diazocine rings and vinyl bromide that is a precursor to some

fire retardant A fire retardant is a substance that is used to slow down or stop the spread of fire or reduce its intensity. This is commonly accomplished by chemical reactions that reduce the flammability of fuels or delay their combustion. Fire retardants ...

s. In

organic synthesis Organic synthesis is a special branch of chemical synthesis and is concerned with the intentional construction of organic compounds. Organic molecules are often more complex than inorganic compounds, and their synthesis has developed into one o ...

, 1,2-dibromoethane is used as a source of bromine to brominate

carbanion In organic chemistry, a carbanion is an anion in which carbon is trivalent (forms three bonds) and bears a formal negative charge (in at least one significant resonance form). Formally, a carbanion is the conjugate base of a carbon acid: :R3 ...

s and to activate

magnesium Magnesium is a chemical element with the symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 of the periodic ...

for certain

Grignard reagent A Grignard reagent or Grignard compound is a chemical compound with the general formula , where X is a halogen and R is an organic group, normally an alkyl or aryl. Two typical examples are methylmagnesium chloride and phenylmagnesium bromide . ...

s. In the latter process, 1,2-dibromoethane reacts with magnesium, producing

ethene Ethylene (IUPAC name: ethene) is a hydrocarbon which has the formula or . It is a colourless, flammable gas with a faint "sweet and musky" odour when pure. It is the simplest alkene (a hydrocarbon with carbon-carbon double bonds). Ethylene i ...

and

magnesium bromide Magnesium bromide is a chemical compound of magnesium and bromine, with the chemical formula . It is white and deliquescent crystalline solid. It is often used as a mild sedative and as an anticonvulsant for treatment of nervous disorders. It is wa ...

, and exposes a freshly etched portion of magnesium to the substrate.

Health effects

1,2-Dibromoethane causes changes in the metabolism and severe destruction of living tissues. The known empirical LD50 values for 1,2-dibromoethane are 140 mg kg⁻¹ (oral, rat), and 300.0 mg kg⁻¹ (dermal, rabbit). 1,2-Dibromoethane is a known

carcinogen A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive sub ...

, with pre-1977 exposure levels ranking it as the most carcinogenic substance on the HERP Index. The effects on people of breathing high levels are not known, but animal studies with short-term exposures to high levels caused depression and collapse, indicating effects on the brain. Changes in the brain and behavior were also seen in young rats whose male parents had breathed 1,2-dibromoethane, and birth defects were observed in the young of animals that were exposed while pregnant. 1,2-Dibromoethane is not known to cause

birth defect A birth defect, also known as a congenital disorder, is an abnormal condition that is present at birth regardless of its cause. Birth defects may result in disabilities that may be physical, intellectual, or developmental. The disabilities ca ...

s in humans. Swallowing has caused death at 40ml doses.

References

External links

National Pollutant Inventory 1,2-Dibromoethane Fact Sheet

Congressional Research Service (CRS) Reports regarding Ethylene Dibromide

ATSDR ToxFAQs

{{DEFAULTSORT:Dibromoethane, 1, 2- Endocrine disruptors Insecticides Bromoalkanes Fumigants Flame retardants Hazardous air pollutants Fuel additives IARC Group 2A carcinogens Sweet-smelling chemicals