1,2-Dibromoethane
Ethylene dibromide
Colorless to yellowish liquid with odor phenolartigem
Liquid
2.18 g · cm -3
10 ° C.
131 ° C.
11.3 hPa ( 20 ° C)
- 5.3 g · l-1 in water (30 ° C)
- Soluble in diethyl ether and ethanol
1.539 (20 ° C)
Risk
-79.2 KJ / mol
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1,2- dibromoethane is a colorless, poisonous liquid that smells like chloroform similar and is mainly used as a solvent for container fumigation and as a synthesis intermediate use.
Production and representation
1,2-dibromoethane can be obtained by direct bromination of ethene ( ie, by a conventional halogen - addition reaction ) can be prepared by reacting with ethyne or hydrobromic acid.
Properties
Dibromoethane is a flammable, colorless to yellowish liquid with phenolartigem odor. At atmospheric pressure, the compound boils at 131 ° C. The enthalpy of vaporization is 41.78 kJ · mol here -1. The vapor pressure function is given by Antoine corresponding log10 (P) = A- ( B / ( T C )) ( P in bar, T in K) with A = 7.36914, B = 4101.146 and C = 153.034 in the temperature range from 246 K to 405 K. vapors of dibromoethane are six times heavier than air. In solid phase two polymorphic crystal forms may be present. The transition point of the low-temperature form II to high temperature form I is located at -23 ° C. The transition enthalpy of this solid phase transition is 1.94 kJ · mol -1. Both forms are enantiotropic each other. The crystal form I at 10 ° C shows a melting point with a heat of fusion of 10.94 kJ · mol -1. The triple point is 10 ° C and 9.2 mbar. Dibromoethane slowly decomposes in sunlight, otherwise the connection is stable.
Use
The customary in the 1980s using 1,2- dibromoethane as an additive in leaded fuel to prevent lead deposits in the engine was stopped because of its toxicity in the industrialized countries.
Safety
1,2- dibromoethane causes severe skin and mucous membranes and is absorbed through the skin. It causes headaches, vomiting, uremia, liver and kidney damage. It is also a carcinogen that for humans is a risk to be and was assigned to the MAK Group III A 2.