Gasoline ethylene dibromide

Much of the bromine output in the U.S. was used in the production of ethylene dibromide, a lead scavenger used in making gasoline antiknock compounds. Lead in gasoline, however, has been drastically reduced, due to environmental considerations. This will greatly affect future production of bromine. 

About 10% is marketed ia elemental form. Eighteen percent is converted to ethylene dibromide [106-93 ] for use ia gasoline and 30% is used ia fire retardants. Fifteen percent is used as a soil fumigant methyl bromide [74-83-9]. Other commercial forms are alkaU metal bromides, ammonium bromide [12124-97-9] and hydrobromic acid [10035-10-6],... 

The mechanism of poisoning automobile exhaust catalysts has been identified (71). Upon combustion in the cylinder tetraethyllead (TEL) produces lead oxide which would accumulate in the combustion chamber except that ethylene dibromide [106-93-4] or other similar haUde compounds were added to the gasoline along with TEL to form volatile lead haUde compounds. Thus lead deposits in the cylinder and on the spark plugs are minimized. Volatile lead hahdes (bromides or chlorides) would then exit the combustion chamber, and such volatile compounds would diffuse to catalyst surfaces by the same mechanisms as do carbon monoxide compounds. When adsorbed on the precious metal catalyst site, lead haUde renders the catalytic site inactive. 

Use of bromine-containing additives (ethylene dibromide) in leaded gasoline results in the release of bromomethane in exhaust fumes (about 70-220 pg/m of exhaust) (Harsch and Rasmussen 1977), and this may have been significant source of bromomethane release in the past. Combustion of unleaded gasoline releases much less bromomethane (about 4-5 pg/m ), so current emissions from this source are presumably much lower than previously, and are likely to decrease further as leaded gasoline continues to be phased out. 

Ethylene dibromide has been used as a scavenger for lead in gasoline, as a general... 

According to the 1981-83 National Occupational Exposure Survey (NOES, 1997), approximately 9000 workers in the United States were potentially exposed to ethylene dibroinide (see General Remarks). Occupational exposures to ethylene dibromide occur in pest control occupations, petroleum refining and waterproofing. In addition, car mechanics and other workers handling leaded gasoline may be dennally exposed to ethylene dibromide. 

Ethylene dibromide (EDB, also 1,2-dibromoethane) is a xenobiotic compound used as a gasoline additive and a soil fumigant. What initial biodegradation product would you expect from this compound ... 

By similar methods, ethylene dibromide [106-93-4] can also be obtained. This compound is used in gasoline as an antiknocking additive. 

That bromine is relatively a less important element from the standpoint of its applications may be seen from the fact that the annual production of bromine in this country is only about one-twentieth that of chlorine. At the present time, the chief use of bromine is in the manufacture of ethylene dibromide (C2H4Br2), which is used in the production of high-test gasolines. Bromine is also used in the production of other bromine compounds. Thus, potassium bromide is used medicinally as a sedative and silver bromide is used in photographic processes, while other compounds of bromine are used in the production of dyes. 

Most of the bromine produced is converted into ethylene dibromide, C2H4Bro, which is an important constituent of ethyl gas, together with tetraethyl lead, (CoH-)4pb. Tetraethyl lead has valuable anti-knock properties, but its continued use would cause damage to a motor through the deposition of metallic lead, unless some way were found to eliminate this deposit. The ethylene dibromide that is added to the gasoline provides bromine on combustion, which combines with the lead, permitting its elimination as lead bromide, PSBro. 

But leaded gasoline gives off free lead as it burns. Free lead is a very toxic element that causes damage to the nervous system. Ethylene dibromide is added to react with free lead and convert it to a safe compound. 

Ethylene dibromide does not completely solve the problem. Some free lead still escapes into the atmosphere. Leaded gasoline has been banned in the United States for many years but is still used in some countries. 

Use Manufacture of ethylene dibromide (antiknock gasoline), organic synthesis, bleaching, water purification, solvent, intermediate for fumigants (methyl bromide), analytical reagent, fireretardant for plastics, dyes, pharmaceuticals, photography, shrink-proofing wool. 

So far as we know, bromine compounds occur naturally only in some marine organisms. Seawater is about 1 X 10 M Br therefore, it is the main source of bromine. Bromine is used to prepare ethylene dibromide (BrCH2CH2Br), which is used as an insecticide and as a scavenger for lead (that is, to combine with lead) in gasoline to keep lead deposits from clogging engines. Recent studies have shown that ethylene dibromide is a very potent carcinogen. 

Ethylene dibromide Probable carcinogen Gasoline, pesticides 50 days 7.4 ppt (SoCAB) —... 

OTHER COMMENTS used in water disinfection used in bleaching fibers and silk used in the manufacture of medicinal bromine compounds and manufacture of anti-knock compounds, such as ethylene bromide, for gasoline chemical intermediate for ethyl bromide, methyl bromide, ethylene dibromide, and other bromine compounds intermediate in manufacture of sedatives, anesthetics, antispasmodic agents, refrigerating and dehumidifying agents use as a fire-retardant for plastics. 

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