Ethylene dibromide volatilization

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. 

Rathbun RE, Tai DY. 1986. Gas-film coefficients for the volatilization of ethylene dibromide from water. Environ Sci Technol 20 949-952. 

Second, reaction 8.9 and other relevant reactions appear to occur preferentially on available solid surfaces, which are often ice crystals but may also be particles of sulfate hazes from volcanic eruptions or human activity. Third, volatile bromine compounds are even more effective (via Br atoms) than chlorine sources at destroying ozone methyl bromide is released into the atmosphere naturally by forest fires and the oceans, but anthropogenic sources include the use of organic bromides as soil fumigants (methyl bromide, ethylene dibromide) and bromofluorocarbons as fire extinguishers (halons such as CFsBr, CF2BrCl, and C2F4Br2). 

These are compds of the general formula R-N(N02)-CH2.CH2-N(N02)-CH2.CH2-N(N02)-CH2, CH2"N(N02) -R. They were patented by Blomquist and Fiedorek (Ref 3) for use in propellants as explosive, practically non-volatile,plasticizers for NC. The dialkyl triethylenetetranitramines are obtained, together with compds of general formula R-N(N02)-CH2-N=N( 0)-0-CH2.CH2-N(N02)-CH2-CH2-N(N02)-R, when N-alkylethylene-dinitramines are treated with ethylene dibromide as described by Franchimont Klobbie (Ref 2)... 

In 1954, Ethylene Dibromide (EDB) was introduced as a product for the preplant treatment of agricultural fields to control nematodes and it is still used worldwide. EDB is a volatile, halogenated hydrocarbon that is usually marketed as a liquid. The liquid is injected 15 to 30 centimeters beneath the soil surface with a tractor driven chisel tool where the vapors permeate soil air spaces and kill the... 

Ethylene dibromide (EDB or dibromoethane) is a volatile liquid produced by the bromination of ethylene. EDB is used as a lead scavenger in leaded gasoline and as a pesticide and fumigant in soil and on grain, fruits, and vegetables. Because EDB has been classified as a suspected human carcinogen and is a male reproductive toxin, its use as a pesticide has been restricted since 1984. 

D5. A column with 29 equilibrium stages and a partial reboiler is being operated at total reflux to separate a mixture of ethylene dibromide and propylene dibromide. Ethylene dibromide is more volatile, and the relative volatility is constant at a value of 1.30. We are measuring a distillate concentration that is 98.4 mol% ethylene dibromide. The column has a total condenser and saturated liquid reflux, and CMO can be assumed. Use the Fenske equation to predict the bottoms conposition. 

---