Hexachloroethane

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Structural formula
Structure of hexachloroethane
General
Surname Hexachloroethane
other names
  • Carbon hexachloride
  • Carbon hexachloride
  • Perchlorethane
  • Hexachloride ethane
  • HCE
  • Hexachlorethylene (historical)
  • Dichloroform
  • R-110
Molecular formula C 2 Cl 6
Brief description

white powder with a camphor- like odor

External identifiers / databases
CAS number 67-72-1
EC number 200-666-4
ECHA InfoCard 100,000,606
PubChem 6214
Wikidata Q415988
properties
Molar mass 236.74 g mol −1
Physical state

firmly

density

2.09 g cm −3

Sublimation point

186.8 ° C

Vapor pressure

0.29 h Pa (20 ° C)

solubility
safety instructions
GHS labeling of hazardous substances
08 - Dangerous to health 07 - Warning 09 - Dangerous for the environment

Caution

H and P phrases H: 315-319-335-351-410
P: 261-273-281-305 + 351 + 338-501
MAK
  • DFG : 9.8 mg m −3
  • Switzerland: 1 ml m −3 or 10 mg m −3
Toxicological data

4460 mg kg −1 ( LD 50 ,  rat ,  oral )

Thermodynamic properties
ΔH f 0

−202.8 kJ / mol

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Hexachloroethane is an organic chemical compound of chlorine that has found many uses.

Occurrence

Hexachloroethane is one of the chlorinated hydrocarbons and is produced from tetrachloroethene by adding chlorine .

Physical Properties

Hexachloroethane has two crystalline modifications: rhombic up to 46 ° C and triclinic between 46 and 71 ° C.

use

Hexachloroethane has been used in two main areas.

Military use

In the military sector, the connection was used to generate artificial fog, also known as Berger fog, until the second half of the 20th century. The French chemist Berger made a mixture of hexachloroethane and zinc , also magnesium or aluminum powder and caused it to ignite. For decades it was the most widely used military means to quickly produce artificial fog, be it from cartridges, smoke pots, artillery shells or grenades. When several accidents occurred around 1970 during Bundeswehr exercises because the fog was inhaled in too high a concentration, this type of fog generation was stopped. Existing stocks were dismantled and put to use in the aluminum industry that was already known around 1935.

Non-ferrous metallurgy

During the melting and casting of aluminum and its alloys, it was found that the manufacture of cast parts that met growing demands (armor also played a role here) was difficult because of the tendency of the aluminum melts to oxidize and absorb hydrogen. The hydrogen solubility in the melt is 15 times higher than in the solid state, so when the melt solidifies, precipitation occurs with the formation of bubbles in the casting. It has been found that flushing the melts with a suitable flushing gas - inert or, better, reactive in a suitable form - lowers the hydrogen content and reduces the problems. As a consequence, chlorine gas was used as a flushing agent for the first time in 1928. Chlorine reacts with aluminum to form aluminum chloride and because this leaves the melt at approx. 180 ° C with a surge, it is suitable as a rinsing agent / degassing agent (see also melt treatment ).

A German Reich Patent (DRP) from 1931, which was also temporarily used in operational practice, provides for cartridges filled with carbon tetrachloride absorbed in kieselguhr as a chlorine carrier. The well-known poisonous substance did not catch on. In search of a less dangerous substance, hexachloroethane was first found in foundries around 1935; According to what was known at the time, it was a harmless solid that was compressed into crystalline form or pressed into briquettes, pure or in preparations (cf. DRP 733616), and soon found general use and was produced in large quantities by the chlorochemical industry until the end of the twentieth century and consumed in aluminum smelters and foundries has been. The Seveso accident , although in no connection with the production and use of hexachloroethane, drew attention to the chlorinated hydrocarbons as a whole, and a possible formation of hexachlorobenzene was finally demonstrated. By oxidative control of the hexachloroethane decomposition in the melt, this possibility can be reduced to below the critical threshold (DP 36 30 711.4), but the "end" for hexachloroethane was only postponed by a few years for this second large area of ​​application.

Today, their use is limited, at least in the EU area, to a few medical products and special technical processes, with the consequence of sharply declining production volumes.

safety instructions

Oral ingestion of hexachloroethane is liver-damaging; when inhaled in high concentrations, it has a slightly narcotic effect. The extent to which it could be carcinogenic has been investigated for a long time; biologically it is not dangerous as a solid substance, as it is insoluble in water. At room temperature it slowly sublimes with a smell of camphor . Thermal decomposition in a molten metal can also produce polychlorinated dibenzodioxins and dibenzofurans .

Individual evidence

  1. ↑ a b c d e f g h Entry on hexachloroethane in the GESTIS substance database of the IFA , accessed on February 1, 2016(JavaScript required) .
  2. ↑ Entry on hexachloroethane. In: Römpp Online . Georg Thieme Verlag, accessed on November 10, 2014.
  3. ↑ Swiss Accident Insurance Fund (Suva): Limit values ​​- current MAK and BAT values (search for 67-72-1 or hexachloroethane ), accessed on November 2, 2015.
  4. ↑ Data sheet hexachloroethane from AlfaAesar, accessed on December 9, 2007 ( PDF )(JavaScript required) .
  5. ↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Standard Thermodynamic Properties of Chemical Substances, pp. 5-21.

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