Although some bromine compounds can be very harmful to the environment (for example bromomethane leads to depletion of ozone in the stratosphere), they are also extremely important in the manufacture of many indispensable compounds.
Uses of bromine
Several important flame retardants, such as tetrabromobisphenol A, are derived from bromine and bromine compounds although there are concerns about the effectiveness of some of them. The flame retardants are, for example, either bonded (chemically) or incorporated physically, into plastics. This is particularly important when plastics are used where there are fire hazards.
Bromine is also used in the manufacture of biocides, such as biobrom (2,2-dibromo-3-nitrilopropionamide). This is used extensively in treating water
Concentrated solutions of calcium bromide and magnesium bromide (collectively known as 'clear brines') are used in oil drilling. They are very dense solutions (ca 1.8 kg m-3) and when poured into the drilling hole, sink through the water to the bottom. They help to lubricate the drill, increasing its capacity to drill deeper. They also help to disperse the solids being drilled out.
Figure 1 The uses of bromine.
While Figure 1 shows data for the worldwide use of bromine, the proportion varies country by country. For example in the US, less (45%) is used to make flame retardants and more (21%) as clear brines for drilling.
A further use of bromine is in making bromomethane, used as a fumigant against pests, and to clean soils before planting. However, this is decreasing in importance as there are international agreements to reduce its use as, like CFCs, it is considered to lead to depletion of ozone when it is transported into the stratosphere. It is now used under strictly limited conditions in developed countries but is allowed to be used until 2015 by developing countries.
Annual production of bromine
Most of the bromine is manufactured in the US and Israel.