General Description
Colorless to pale yellow liquid with a sweet odor. Sinks in water.
Reactivity Profile
1,1,2,2-TETRACHLOROETHANE(79-34-5) may be incompatible with strong oxidizing and reducing agents. Also may be incompatible with many amines, nitrides, azo/diazo compounds, alkali metals, and epoxides. Decomposed by heat and UV light, forming phosgene and HCl; reacts violently with finely dispersed metals [Handling Chemicals Safely 1980. p. 886].
Air & Water Reactions
Insoluble in water.
Health Hazard
Compound is a powerful narcotic and liver poison; may also cause changes in blood composition and neurological disturbances. Repeated exposure by inhalation can be fatal. Ingestion causes vomiting, diarrhea, severe mucosal injury, liver necrosis, cyanosis, unconsciousness, loss of reflexes, and death. Contact with eyes causes irritation and lachrymation. Can be absorbed through the skin and may produce severe skin lesions.
Potential Exposure
Tetrachloroethane is used as an intermediate in the trichloroethylene production from acetylene and as a solvent; as a dry cleaning agent; as a fumigant; in cement; and in lacquers. It is used in the manufacture of artificial silk, artificial leather, and artificial pearls. Recently, its use as a solvent has declined due to replacement by less toxic compounds. It is also used in the estimation of water content in tobacco and many drugs, and as a solvent for chromium chloride impregnation of furs.
Fire Hazard
Special Hazards of Combustion Products: Irritating hydrogen chloride vapor may form in fire.
First aid
If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the skin, remove contaminated clothing and wash immediately with soap and water. Seek medical attention immediately. If this chemical has been inhaled, remove from exposure, begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if heart action has stopped. Transfer promptly to a medical facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce vomiting. Do not make an unconscious person vomit.
Shipping
UN1702 Tetrachloroethane or 1,1,2,2Tetrachloroe thane, Hazard Class: 6.1; Labels: 6.1Poisonous materials.
Incompatibilities
Violent reaction with chemically active metals; strong caustics; strong acids; especially fuming sulfuric acid. Degrades slowly when exposed to air. Attacks plastic and rubber.
Chemical Properties
colourless to light yellow liquid with a chloroform-like
Chemical Properties
Tetrachloroethane is a heavy, volatile colorless to light yellow liquid. It has a sweetish, chloroform-like odor. The Odor Threshold is 0.5 ppm in water and 1.5 ppm in air.
Waste Disposal
Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal. Incineration, preferably after mixing with another combustible fuel. Care must be exercised to assure complete combustion to prevent the formation of phosgene. An acid scrubber is necessary to remove the halo acids produced.
Physical properties
Colorless to pale yellow liquid with a sweet, chloroform-like odor. A detection odor threshold
concentration of 50 mg/m3 (7.3 ppmv) was experimentally determined by Dravnieks (1974).
Uses
1,1,2,2-Tetrachloroethane, once used as a solvent for cleaning
and extraction processes, is still used to some extent as a
chemical intermediate. Present usage is quite limited because
less toxic solvents are available.
Uses
Intermediate in the production of
trichloroethylene, tetrachloroethylene, and
1,2-dichloroethylene; previously used as a
solvent, insecticide and fumigant.
Uses
Nonflammable solvent for fats, oils, waxes, resins, cellulose acetate, rubber, copal, phosphorus, sulfur. As solvent in certain types of Friedel-Crafts reactions or phthalic anhydride condensations. In the manufacture of paint, varnish, and rust removers. In soil sterilization and weed killer and insecticide formulations. In the determination of theobromine in cacao. As immersion fluid in crystallography. In the biological laboratory to produce pathological changes in gastrointestinal tract, liver, and kidneys. Intermediate in the manufacture of trichloroethylene and other chlorinated hydrocarbons having two carbon atoms.
Definition
ChEBI: A member of the class of chloroethanes that is ethane substituted by chloro groups at positions 1, 1, 2 and 2.
Hazard
Toxic by ingestion, inhalation, skin absorption.
Questionable carcinogen.
Carcinogenicity
The EPA has classified this
material as “likely to be carcinogenic to humans” based on data from an oral cancer bioassay in male and female
Osborne–Mendel rats and B6C3F1 mice. In mice, a
significant increase in the incidence of hepatoceullar carcinomas
in both genders was observed. Male Osborne–Mendel
rats showed increased incidence of hepatocellular carcinomas,
which is a rare tumor in this strain.
The National Cancer Institute has included 1,1,2,2-
tetrachloroethane in their bioassay series using rats and mice.
Their summary states that the time-weighted average doses
(by gavage) were 108 and 62 mg/kg/day for male rats, 76 and
43 mg/kg/day for female rats, and 282 and 142 mg/kg/day for
all mice. There was a highly significant positive dose-related
trend in the incidence of hepatocellular carcinoma in mice of
both sexes. No statistically significant incidence of neoplastic
lesions was observed in male or female rats. However, two
hepatocellular carcinomas and one neoplastic nodule, which
are rare tumors in the male Osborne–Mendel rat, were
observed in high-dose males. Under the conditions of this
bioassay, orally administered 1,1,2,2-tetrachloroethane was
a liver carcinogen in B6C3Fl mice of both sexes.
The proposed metabolic pathway involves the production
of dichloroacetic acid, which was identified as the
major urinary metabolite in treated mice. Other pathways
involve formation of trichloroethylene via dehydrochlorination
or tetrachloroethylene via oxidation. Free radicals may
also be formed.
From the NCI study, a oral slope factor (OSF) of 0.2
per mg/kg/day was developed by the EPA. No inhalation unit
risk (IUR) was determined by the EPA because of absence of
data from inhalation exposure.
Environmental Fate
Biological. Monodechlorination by microbes under laboratory conditions produced 1,1,2-
trichloroethane (Smith and Dragun, 1984). In a static-culture-flask screening test, 1,1,2,2-
tetrachloroethane (5 and 10 mg/L) was statically incubated in the dark at 25 °C with yeast extract
and settled domestic wastewater inoculum. No significant degradation was observed after 28 d of
incubation (Tabak et al., 1981).
Chemical/Physical. In an aqueous solution containing 0.100 M phosphate-buffered distilled
water, 1,1,2,2-tetrachloroethane was abiotically transformed to 1,1,2-trichloroethane. This reaction
was investigated within a temperature range of 30 to 95 °C at various pHs (5 to 9) (Cooper et al.,
1987). Abiotic dehydrohalogenation of 1,1,2,2-tetrachloroethane yielded trichloroethylene (Vogel
et al., 1987) and HCl (Kollig, 1993). The half-life for this reaction at 20 °C was reported to be 0.8
yr (Vogel et al., 1987). Under alkaline conditions, 1,1,2,2-tetrachloroethane dehydrohalogenated
to trichloroethylene. The reported hydrolysis half-life of 1,1,2,2-tetrachloroethane in water at 25
°C and pH 7 is 146 d (Jeffers et al., 1989).
The evaporation half-life of 1,1,2,2-tetrachloroethane (1 mg/L) from water at 25 °C using a
shallow-pitch propeller stirrer at 200 rpm at an average depth of 6.5 cm was 55.2 min (Dilling,
1977).
At influent concentrations of 1.0, 0.1, 0.01, and 0.001 mg/L, the GAC adsorption capacities
were 11, 4.5, 1.9, and 0.8 mg/g, respectively (Dobbs and Cohen, 1980).
Purification Methods
Stir the ethane, on a steam-bath, with conc H2SO4 until a fresh portion of acid remains colourless. The organic phase is then separated, distilled in steam, dried (CaCl2 or K2CO3), and fractionally distilled in a vacuum. [Beilstein 1 IV 144.]
Toxicity evaluation
Metabolism of tetrachloroethane to reactive products plays
a key role in its toxicity. Both nuclear and microsomal cytochrome
P450 enzymes have been implicated in the metabolism
of the compound, possibly releasing aldehydes, alkenes,
acids, and free radicals that may react with biological tissues.
Therefore, because of high metabolic activity of the liver, the
formation of active metabolites is a likely mechanism for the
toxicity tetrachloroethane. Hence, tetrachloroethane metabolism
could result in the reductive formation of radical products,
leading to the stimulation of lipid peroxidation resulting in
hepatotoxic effects, as noted in carbon tetrachloride, a structurally
related chlorinated alkane. Both dichloroacetic and trichloroacetic
acids are known to cause proliferation of
peroxisomes.
The mechanism of neurological toxicity of tetrachloroethane
has not been well characterized. Studies of similar
compounds suggest that the parent compound itself may be
the causative agent. This property allows interference with
neural membrane function, bringing about central nervous
system depression, behavioral changes, and anesthesia.
The mechanisms by which tetrachloroethane produces
carcinogenic effects are incompletely characterized. Tetrachloroethane
has been shown to bind to DNA in the liver and several
other organs in rats and mice, which may contribute to the
carcinogenic process. Studies indicate that there may be initiating
and promoting activities when tetrachloroethane is metabolized,
possibly by cytochrome P450 enzymes producing urinary
metabolites such as dichloroacetic acid, trichloroacetic acid,
trichloroethylene, and tetrachloroethylene. Studies of chronic exposure of rats and mice to these specific metabolites revealed
hepatic tumors in male and female mice. Although it is possible
that the carcinogenicity of tetrachloroethane involves metabolism
with these compounds, there is no direct evidence linking
one or more metabolites to its carcinogenic effects. Tetrachloroethane
may be metabolized to form free radicals, which
can in turn covalently bind to tissues, including DNA.
