Brominated flame retardants
represent a commodity of growing importance, and represent the largest use of bromine. When the brominated material burns, the flame retardant produces hydrobromic acid
which interferes in the radical chain reaction
of the oxidation
reaction of the fire. The mechanism is that the highly reactive hydrogen oxygen and hydroxy radicals react with hydrobromic acid and form less reactive bromine radicals (free bromine atoms). These also react with radicals in the first to help terminate the reaction.
The bromine-containing compounds can be placed in the polymers either during polymerization
if a small amount of brominated monomer is added or the bromine containing compound is added after polymerization. Tetrabromobisphenol A
can be added to produce polyesters
or epoxy resins. Epoxy used in printed circuit boards
(PCB) are normally made from flame retardant resins, indicated by the FR in the abbreviation of the products (FR-4
. Vinyl bromide
can be used in the production of polyethylene
. Decabromodiphenyl ether
can be added to the final polymers.
was an additive in gasolines
containing lead anti-engine knocking
agents. It scavenges lead by forming volatile lead bromide, which is exhausted from the engine. This application accounted for 77% of the bromine uses in 1966 in the US. This application has declined since the 1970s due to environmental regulations.
Ethylene bromide is also used as a fumigant, but again this application is declining.
These volatile organobromine compounds are all now regulated as ozone depletion
agents (see below).
Poisonous methyl bromide
was widely used as pesticide
soil and to fumagate housing, by the tenting method. The Montreal Protocol on Substances that Deplete the Ozone
scheduled the phase out for the ozone depleting
chemical by 2005, and it is no longer used (in housing fumagation it has been replaced by such compounds as sulfuryl fluoride
, which contain neither the chlorine or bromine organics which harm ozone). Prior to the Montreal protocol in 1991 (for example) an estimated 35,000 metric tons of the chemical were used to control nematodes
and other soil-borne diseases.
Medical and veterinary
compounds, especially potassium bromide
, were frequently used as general sedatives in the 19th and early 20th century. Bromides in the form of simple salts are still used as anticonvulsants, in both veterinary and human medicine.