Bromine Compounds
Authors: Jackisch Philip F. 
Published: August 2004

Bromamide, NH2Br, is formed from bromine and liquid ammonia. NH2Br and bromimide, NHBr2, are formed when bromine reacts with ammonia in ether solution at low temperatures. These products have not been isolated. In swimming pools disinfected by bromine, bromamide and bromimide can form. These compounds have about half the disinfecting power of HOBr giving bromine an advantage compared to chlorine. Hydrogen bromide, HBr, (hydrobromic acid), is a colorless gas that fumes strongly in moist air. The gas is highly soluble in water, forming azeotropic mixtures the compositions of which have been determined at various pressures. The manufacture of HBr gas involves burning a mixture of hydrogen and bromine vapor. Hydrobromic acid is one of the strongest mineral acids. It is a more effective solvent for some ore minerals than hydrochloric acid because of its higher boiling point and stronger reducing action. The liquid and vapors of hydrobromic acid are highly corrosive to tissue. Inhalation of vapor is so irritating to the nose and throat that a person does not voluntarily remain in an area when vapors are present in hazardous concentrations. Symptoms of overexposure to HBr include coughing, choking, burning in the throat, wheezing, or asphyxia. Ingestion causes severe burns of the mouth and stomach and skin contact can cause severe burns. In the case of liquid or vapor contact with eyes, permanent damage may result. Suitable safety equipment should be used when handling HBr and a safety shower and eye bath should be available. HBr reacts with metals, producing highly explosive hydrogen gas. Technical 48% and 62% acids are colorless‐to‐light yellow liquids. They are classified under DOT regulations as corrosive materials. Anhydrous hydrogen bromide is classified as a nonflammable gas. A considerable amount of hydrobromic acid is consumed in the manufacture of inorganic bromides, as well as in the synthesis of alkyl bromides from alcohols. Anhydrous lithium bromide, LiBr, is a desiccant useful in the industrial drying of air. Sodium bromide, NaBr, is an effective biocide in cooling water systems. Sodium bromide and potassium bromide, KBr, are used to prepare light‐sensitive emulsions for photography. Potassium bromide is also used in process engraving. These three bromides have medical applications as sedatives, hypnotics, or anticonvulsants. Magnesium bromine, MgBr2, is used in organic synthesis. A concentrated solution of calcium bromide, CaBr2, in water is useful as a completion, workover, and packer fluid in oil‐well drilling and maintenance. In medicine magnesium bromide and calcium bromide are sedatives and anticonvulsants. Titanium bromide, TiBr4, ferrous bromide, FeBr2and cuprous bromide, CuBr, Silver bromide, AgBr, is used in photography, as a topical antiinfective, and as an astringent. Boron tribromide, BBr3, is used in the manufacture of diborane and in the production of ultra high purity boron. Ammonium bromide, NH4Br, is used in photography, process engraving and lithography, fireproofing of wood, corrosion inhibitors, and in medicine as a sedative. Bromine and chlorine react reversibly in the liquid or vapor states to form bromine chloride, BrCl. Bromine chloride is a dark red, fuming, lachrimatory liquid. Bromine chloride is used as a brominating agent in the preparation of fire‐retardant chemicals, pharmaceuticals, high density brominated liquids, agricultural chemicals, dyes, bleaching agents, and in water treatment, eg, in cooling towers and effluent streams from sewage plants. Hypobromites, the salts of hypobromous acid, gradually disproportionate to bromide and bromate. Hypobromites are strong bleaching agents, similar to hypochlorites. Sodium bromite is used as a desizing agent in the textile industry. Bromates are stable in storage. They have various uses based on their oxidizing power. Bromates represent a potential fire and explosion hazard if heated, subjected to shock, or acidified. They should not be allowed to contact reactive organic matter, including paper and wood. For shipment, a yellow oxidizer label is required under DOT regulations. An important use for sodium bromate, NaBrO3, is as a neutralizer or oxidizer in certain hair‐wave preparations. The primary use for potassium bromate, KBrO3, is in flour treatment. In analytical chemistry potassium bromate is used as a primary standard and a brominating agent. Organic compounds of bromine usually resemble their chlorine analogues but have higher densities and lower vapor pressures. The bromo compounds are more reactive toward alkalies and metals. Methyl bromide (bromomethane), CH3Br, is a colorless liquid or gas with practically no odor. The liquid is miscible with most organic solvents and forms a bulky, crystalline hydrate below 4°C. Methyl bromide is useful in a variety of methylation reactions, such as the syntheses of ethers, sulfides, esters, and amines. Methyl bromide reacts readily with a number of metals to form organometallic reagents useful as catalysts or for the introduction of a methyl group into a variety of organic or organometallic compounds. Reaction with magnesium gives the well‐known Grignard reagent, usually prepared in an ether solvent. Methyl bromide is nonflammable over a wide range of concentrations in air at atmospheric pressure and offers practically no fire hazard. Commercial manufacture of methyl bromide is generally based on the reaction of hydrogen bromide with methanol. Vapor trapped next to the skin can cause severe delayed burns. Methyl bromide is corrosive to the eyes. Inhalation of this chemical can cause dizziness, nausea, vomiting, headache, drowsiness, dimming of vision, and death. Respiratory tract inflammation can occur from breathing methyl bromide, with symptoms delayed 2–48 h. Repeated and prolonged exposure to lower concentrations (30–100 ppm) causes severe nervous system effects. Methyl bromide has been shown to be mutagenic in laboratory tests. The primary use for methyl bromide is in the extermination of insect and rodent pests. The material is suitable for the fumigation of food commodities and the facilities in which these foods are processed or stored. Methyl bromide finds use as a methylating agent in the syntheses of agricultural and drug chemicals. Bromochloromethane (methylene chlorobromide), CH2BrCl, is a clear, colorless liquid with a characteristic sweet odor and very low freezing point. The principal outlet for bromochloromethane is as a fire‐extinguisher fluid. It is also used as an explosion suppression agent and as an intermediate and solvent in the manufacture of pesticides and other products. Dibromomethane (methylene bromide), CH2Br2, is a similar liquid. The compound is used as a solvent, as a gauge fluid, and in producing pesticides. Both of these dihalomethanes can be used as dense, readily volatile media for mineral and salt separations. Tribromomethane (bromoform), CHBr3, is usually sold mixed with up to 3–4% ethanol as a stabilizer. Uses have been found in syntheses and in pharmacy as a sedative and antitussive. Ethyl bromide (bromoethane), CH3CH2Br, is a volatile, clear, colorless liquid. Ethyl bromide is used mainly as an ethylating agent in syntheses, particularly of pharmaceuticals. Its toxicity is markedly lower than that of methyl bromide. Ethylene dibromide (ethylene bromide, 1,2‐dibromoethane), CH2BrCH2Br, is a clear, colorless liquid with a characteristic sweet odor. Ethylene dibromide is nonflammable and under ordinary conditions is quite stable. Ethylene glycol is produced by high temperature hydrolysis under pressure, and the reaction with zinc in alcohol yields ethylene and zinc bromide. Ethylene dibromide is a suspected human carcinogen and worker exposure should be carefully controlled. Ethylene dibromide causes severe blistering of the skin if contact is prolonged. Eye contact with the liquid will cause pain, irritation, and temporary impairment of vision. Ethylene dibromide is one of the lowest cost organic compounds of bromine. This compound has found its primary use as an exhaust system scavenger in gasoline containing lead antiknocks. Other uses are in the manufacturing of dyes, pharmaceuticals, polymers, and other chemicals. Bromine compounds are used in dyes and indicators, flame retardants, pesticides, and pharmaceuticals.