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

chemical formula 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, such as pare ...

. Although trace amounts occur naturally in the

ocean The ocean is the body of salt water that covers approximately 70.8% of Earth. The ocean is conventionally divided into large bodies of water, which are also referred to as ''oceans'' (the Pacific, Atlantic, Indian Ocean, Indian, Southern Ocean ...

, where it is probably formed by

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

and kelp, substantial amounts are produced industrially. It is a dense colorless liquid with a faint, sweet odor, detectable at 10 ppm. It is a widely used and sometimes-controversial fumigant. The combustion of 1,2-dibromoethane produces hydrogen bromide gas that is significantly corrosive.

Preparation and use

It is produced by the reaction of ethylene gas with

bromine Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between th ...

, 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 used to control pests. They include herbicides, insecticides, nematicides, fungicides, and many others (see table). The most common of these are herbicides, which account for approximately 50% of all p ...

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

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 a group of detritivore, detritophagous Eusociality, eusocial cockroaches which consume a variety of Detritus, decaying plant material, generally in the form of wood, Plant litter, leaf litter, and Humus, soil humus. They are dist ...

s and

beetle Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...

s, and for control of

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

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 retardants. In organic synthesis, 1,2-dibromoethane is used to brominate carbanions and to activate

magnesium Magnesium is a chemical element; it has Symbol (chemistry), 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 ...

for certain Grignard reagents. In the latter process, 1,2-dibromoethane reacts with magnesium, producing ethylene and magnesium bromide, which are innocuous, exposing a more active portion of the magnesium particle to the substrate.

Health effects

1,2-Dibromoethane causes changes in the

metabolism Metabolism (, from ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the co ...

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 agent that promotes the development of cancer. Carcinogens can include synthetic chemicals, naturally occurring substances, physical agents such as ionizing and non-ionizing radiation, and biologic agents such as viruse ...

, 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 defects 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 Fuel additives IARC Group 2A carcinogens Sweet-smelling chemicals