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DESIGNATIONS
CAS No.: 7726-95-6
Registry name: Bromine
Chemical name : Bromine
Synonyms, Trade names: Bromine
Chemical name (German): Brom
Chemical name (French): Brome
Appearance: dark, reddish-brown, fuming, highly volatile liquid or vapour (below -7.2°C metal-like crystals, colourless at -252°C)
BASIC CHEMICAL AND PHYSICAL DATA
| Empirical formula: | Br2 |
| Rel. molecular mass: | 159.80 g |
| Density: | 3.12 g/cm3 |
| Relative gas density: | 5.5 |
| Boiling point: | 58.78°C |
| Melting point: | -7.2°C |
| Vapour pressure: | 220 hPa at 20°C; 340 hPa at 30°C; 740 hPa at 50 °C |
| Odour threshold: | 1 ppm in air |
| Solvolysis/solubility: | in water 42 g/l at 0°C |
| 35.5 g/l at 20°C | |
| soluble in benzene, gasoline, chloroform, ethanol, ether and hydrogen sulphide | |
| Conversion factors: | 1 mg/m3 = 0.150 ml/m3 |
| 1 ml/m3 = 6.658 mg/m3 | |
| Note: | Apart from mercury, bromine is the only element which is liquid at room temperature. Bromine is highly reactive: it reacts explosively with several metals, corrodes many organic substances and reacts as an oxidising agent. |
ORIGIN AND USE
Usage:
Most bromine (about 30 %) is used to produce
1,2-dibromoethane which is added to fuels containing tetraethyl
lead to stop lead deposits collecting on the valves of
internal-combustion engines. Further uses are the production of
oil well packs and completion fluids as calcium bromide (22 %)
and in flame retardants (16 %). It is used as starting material
for the organic synthesis of pesticides, dyes, medicines,
photographic chemicals and contrast media.
Origin/derivation:
Bromine is mainly obtained from waste lyes in the potassium
industry; seawater is a further source. Waste lyes, brine and
mother liquids etc. with a bromine content of
> 1 g/l are processed by means of hot debromination,
with cold debromination being used for seawater. Subsequent
distillation and drying remove chlorine, residual water and
impurities from the raw bromine segregated from the aqueous phase
(99% yield).
Production figures:
Worldwide
1982 = 381,000 t (ULLMANN, 1985)
1983 = 364,200 t
1984 = 373,000 t
Toxicity
| Humans: | LDLo 14 mg/kg, oral | acc. UBA, 1986 |
| LCLo 1000 ppm, res. air (inhal.) = lethal | acc. UBA, 1986 | |
| Mammals: | ||
| Mouse | LC50 750 ppm (9 min), inhalation | acc. UBA, 1986 |
| Cat | LCLo 140 ppm (7 h), inhalation | acc. UBA, 1986 |
| Rabbit | LCLo 180 ppm (6.5 h), inhalation | acc. UBA, 1986 |
| Aquatic organisms: | ||
| Goldfish | 20 mg/l = lethal | acc. UBA, 1986 |
| Small crustaceans | 10 mg/l = lethal | acc. UBA, 1986 |
Characteristic effects:
Humans/mammals: The liquid produces severe, poorly healing irritation and burning of the eyes, the respiratory organs, the skin and the gastro-intestinal tract. Deep, painful necroses form on the skin and the mucous membranes. High concentrations cause oedemas of the glottis, larynx and lungs as well as inflammation of the lungs. Poison class 2 (ROTH, 1989). Bromine vapours are even more hazardous as they produce bronchial spasms and pneumonia.
Plants: Bromine is a trace element. Bromides do not damage plants, but are not necessarily required.
ENVIRONMENTAL BEHAVIOUR
Water:
Bromine is denser than water, but dissolves slightly in water and
colours it brown. This is followed by the generation of bromine
vapours. There is a strong hazard to all types of water, in
particular to drinking water, service water and waste water on
account of the high toxicity linked to oxidising and corrosive
properties. Bromides are found as accompanying ions in potassium
and sodium deposits. The bromide content rises with increasing
salinity. In coastal areas, higher bromide concentrations in the
groundwater can be attributed to the infiltration of seawater.
Water hazard class 2 (ROTH, 1989). Bromine prevents the
formation of algae in water.
Air:
The liquid readily evaporates and forms caustic vapours. The
vapours are denser than air and creep along the ground.
ENVIRONMENTAL STANDARDS
| Medium/acceptor | Sector | Country/organ. | Status |
Value | Cat. | Remarks | Source |
| Soil: | NL | G |
20 mg/kg AD | acc. KLOKE, 1988 | |||
| NL | G |
50 mg/kg AD | Investigation | acc. KLOKE, 1988 | |||
| NL | G |
300 mg/kg AD | Rehabilitation | acc. KLOKE, 1988 | |||
| Air: | Workp | D | L |
0.1 ml/m3 | MAK | DFG, 1989 | |
| Workp | USA | (L) |
0.7 mg/m3 | TWA | acc. ACGIH, 1986 | ||
| Workp | USA | (L) |
2 mg/m3 | STEL | acc. UBA, 1986 | ||
| Workp | SU | (L) |
0.075 ml/m3 | acc. UBA, 1986 | |||
| Workp | SU | (L) |
1 mg/m3 | Skin resorption | acc. KETTNER, 1979 | ||
| Emiss. | D | L | 5 mg/m3 | mass flow > 50 g/h | acc. TA Luft, 1986 |
Comparison/reference values
| Medium/origin | Country | Value | Source |
| Seawater | 0.065 kg/m3 | acc. ULLMANN, 1978 | |
| Fly ash (coal) | USA | 0.3-21 mg/kg | acc. HOCK, 1988 |
| Plants | 15 mg/kg | acc. HOCK, 1988 |
Assessment/comments
The biological action of bromine and its compounds is quite similar to that of chlorine and its compounds. However, most bromine compounds are more toxic than the corresponding chlorine compounds while chlorine itself is more hazardous than bromine because of its reactivity.