Boron tribromide is a chemical compound of boron and bromine. It is a commercially available strong Lewis acid. Boron tribromide is an excellent demethylating or dealkylating agent for ethers and is often used in the production of pharmaceuticals. Additionally, it also finds applications in olefin polymerization and in Friedel-Crafts chemistry as a Lewis acid catalyst. The electronics industry uses boron tribromide as a boron source in pre-deposition processes for doping in the manufacture of semiconductors. Bromine is a halogen element with the symbol Br and atomic number 35. Diatomic bromine does not occur naturally, but bromine salts can be found in crustal rock. (2, 5)
belongs to the class of inorganic compounds known as metalloid bromides. These are inorganic compounds in which the largest halogen atom is Bromine, and the heaviest metal atom a metalloid.
Bromine is a powerful oxidizing agent and is able to release oxygen free radicals from the water in mucous membranes. These free radicals are also potent oxidizers and produce tissue damage. In additon, the formation of hydrobromic and bromic acids will result in secondary irritation. The bromide ion is also known to affect the central nervous system, causing bromism. This is believed to be a result of bromide ions substituting for chloride ions in the in actions of neurotransmitters and transport systems, thus affecting numerous synaptic processes. (3, 4, 1)
Metabolism
Bromine is mainly absorbed via inhalation, but may also enter the body through dermal contact. Bromine salts can be ingested. Due to its reactivity, bromine quickly forms bromide and may be deposited in the tissues, displacing other halogens. (3)
No indication of carcinogenicity to humans (not listed by IARC).
Uses/Sources
Boron tribromide is an excellent demethylating or dealkylating agent for ethers and is often used in the production of pharmaceuticals. Additionally, it also finds applications in olefin polymerization and in Friedel-Crafts chemistry as a Lewis acid catalyst. The electronics industry uses boron tribromide as a boron source in pre-deposition processes for doping in the manufacture of semiconductors. (5)
Minimum Risk Level
Not Available
Health Effects
Bromine vapour causes irritation and direct damage to the mucous membranes. Elemental bromine also burns the skin. The bromide ion is a central nervous system depressant and chronic exposure produces neuronal effects. This is called bromism and can result in central reactions reaching from somnolence to coma, cachexia, exicosis, loss of reflexes or pathologic reflexes, clonic seizures, tremor, ataxia, loss of neural sensitivity, paresis, papillar edema of the eyes, abnormal speech, cerebral edema, delirium, aggressiveness, and psychoses. (2, 3, 4)
Symptoms
Bromine vapour causes irritation and direct damage to the mucous membranes. Symptoms include lacrimation, rhinorrhoea, eye irritation with mucous secretions from the oropharyngeal and upper airways, coughing, dyspnoea, choking, wheezing, epistaxis, and headache. The bromide ion is a central nervous system depressant producing ataxia, slurred speech, tremor, nausea, vomiting, lethargy, dizziness, visual disturbances, unsteadiness, headaches, impaired memory and concentration, disorientation and hallucinations. This is called bromism. (3, 4)
Treatment
EYES: irrigate opened eyes for several minutes under running water.
INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice.
SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention.
INHALATION: supply fresh air. If required provide artificial respiration.
