1,2-Dibromotetrachloroethane

1,2-Dibromotetrachloroethane (DBTCE) is an organohalide with the chemical formula C2Br2Cl4. It is a crystalline solid that emits lachrymatory (tear-producing) vapours.[2] Dibromotetrachloroethane can be used as a fungicide,[2] flame retardant[3] and a source for bromine in the laboratory.[4] Because the 1,1-dibromotetrachloroethane isomer is rare, 1,2-dibromotetrachloroethane is frequently referred to as simply dibromotetrachloroethane.

1,2-Dibromotetrachloroethane
Names
IUPAC name
1,2-dibromo-1,1,2,2-tetrachloroethane
Other names
dibromotetrachloroethane, sym-Dibromotetrachloroethane, DBTCE, Bromure de chloréthose ("bromide of chlorethose")
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.010.125 Edit this at Wikidata
EC Number
  • 211-136-7
UNII
  • InChI=1S/C2Br2Cl4/c3-1(5,6)2(4,7)8
    Key: WJUKOGPNGRUXMG-UHFFFAOYSA-N
  • ClC(Cl)(Br)C(Cl)(Cl)Br
Properties
C2Br2Cl4
Molar mass 325.63 g·mol−1
Appearance Crystalline solid
Hazards
GHS labelling:[1]
GHS07: Exclamation mark
Warning
H302, H315, H319, H335
P261, P264, P264+P265, P270, P271, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P319, P321, P330, P332+P317, P337+P317, P362+P364, P403+P233, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Reactions and synthesis

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Dibromotetrachloroethane decomposes to Tetrachloroethylene and bromine when heated. Reacted with potassium sulphide, it gives tetrachloroethylene, potassium bromide and sulphur:[5]

C2Br2Cl4 + K2S → C2Cl4 + S + 2 KBr

Dibromotetrachloroethane, when reacted with aniline at 140 to 150 °C, gives pure tetrachloroethylene.[6]

When reacted with compounds like cyclohexene, 2,2,4-trimethylpentl-ene, 1-hexene, 1-octene, 2-methyl-1-butene and 2,2,4-trimethyl-2-pentene, it yields allylic monobromides via bromination. Dibromotetrachloroethane loses both of its bromine atoms, leaving tetrachloroethylene and hydrogen bromide.[7]

Dibromotetrachloroethane was discovered by the Italian chemist Faustino Malaguti in 1846.[8] Malaguti exposed a mixture of Tetrachloroethylene (then known as chloréthose) and bromine to sunlight. It was named Bromure de chloréthose ("bromide of chlorethose") after its synthesis method.[5] Similar to Malaguti's method, modern synthesis of dibromotetrachloroethane uses bromine dissolved in carbon tetrachloride.

References

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  1. ^ "1,2-Dibromotetrachloroethane". pubchem.ncbi.nlm.nih.gov.
  2. ^ a b Dewayne Torgeson, Agricultural and Industrial Applications Environmental Interactions: An Advanced Treatise (2012), p. 333
  3. ^ Richard Montgomery Stephenson, Stanisław Malanowski, Handbook of the Thermodynamics of Organic Compounds (2012), p.20
  4. ^ B. Iddon, Basil John Wakefield, D. Price, Bromine Compounds: Chemistry and Applications (1988)
  5. ^ a b Edmond Frémy, Paul Louis Chastain, Encyclopédie Chimique (1883) p. 235
  6. ^ E. Burgoin, Preparation of Perchlorethylene (1870)
  7. ^ G. H. Williams Advances in Free-radical Chemistry (1972), p. 186
  8. ^ Faustino Malaguti, Recherches sur Éthers Chlorés, Annales de Chimie et de Physique, 16-3, p. 24