1,1,2-Trichloroethane

Chemical Properties

Clear, colorless liquid; characteristic sweet odor. Miscible with alcohols, ethers, esters, and ketones; insoluble in water. Nonflammable.

Chemical Properties

1,1,2-Trichloroethane is a colorless, nonflammable (must be pre-heated before ignition can occur) liquid Sweet, chloroform-like odor.

Physical properties

Colorless liquid with a pleasant, sweet, chloroform-like odor

Uses

Intermediate in the production of vinylidene chloride; solvent.

Uses

Solvent for fats, oils, waxes, resins, other products; organic synthesis.

Uses

The use of 1,1,2-trichloroethane is quite restrictive. It is used to a slight extent as a specialty solvent and mostly as a chemical intermediate; a solvent for fats, waxes, natural resins, alkaloids, and various other organic materials; as an intermediate in production of vinylidene chloride and teflon tubing; and as a component of adhesives. The availability of other less toxic solvents discourages its use. More than 95% of this compound manufactured in the United States is consumed in producing vinylidene chloride. Domestic production is about 410 million pounds. It must not be confused with its much less toxic isomer, 1,1,1- trichloroethane.

Definition

ChEBI: A member of the class of chloroethanes that is ethane substituted by chloro groups at positions 1, 1 and 2.

General Description

A clear light colored liquid. Flash point between 0 and 74°F. Insoluble in water and slightly denser than water. Hence sinks in water. May be toxic by inhalation.

Reactivity Profile

1,1,2-Trichloroethane is sensitive to light and heat. Incompatible with strong oxidizing agents and strong bases. Reacts violently with sodium, potassium, magnesium, and aluminum. Attacks some plastics, rubber and coatings.

Health Hazard

Inhalation causes irritation of the nose, throat, and lungs. High concentrations may cause death by respiratory failure. Highly toxic by ingestion; may cause liver or kidney damage or myocardial irritability. Causes severe irritation of the gastrointestinal tract. Vapor may produce superficial skin burns or defatting type dermatitis and may irritate the eyes.

Safety Profile

Suspected carcinogen with experimental carcinogenic data. Poison by ingestion, intravenous, and subcutaneous routes. Moderately toxic by inhalation, skin contact, and intraperitoneal routes. Experimental reproductive effects. Mutation data reported. An eye and severe skin irritant. Has narcotic properties and acts as a local irritant to the eyes, nose, and lungs. It may also be injurious to the liver and kidneys. Incompatible with potassium. When heated to decomposition it emits toxic fumes of Cl-. See also CHLORINATED HYDROCARBONS, ALIPHATIC; and other trichloroethane entries,

Synthesis

First, trichloroethane was put into the reactor, and then trichloroethylene and chlorine gas in 1:1.2 molar ratio were passed at 20~25° for reaction. After water washing and separation, the finished product is obtained. ClCH=CH2+Cl2→Cl2CHCHCl

Potential Exposure

1,1,2-Trichloroethane is used as an intermediate in the production of vinylidine chloride, and a component of adhesives; as a solvent; but is not as widely used as is its isomer 1,1,1-Trichloroethane; it is an isomer of 1,1,1-Trichloroethane but should not be confused with it toxicologically. 1,1,2-Trichloroethane is comparable to carbon tetrachloride and tetrachloroethane in toxicity. Forms a flammable vapor
air mixture at 43℃ and higher.

Carcinogenicity

According to the NCI, 1,1,2-trichloroethane has been included in the NCI bioassay program, in which it was fed by gavage to rats and mice. As in many of these studies with hepatotoxic compounds, hepatocellular carcinomas occurred in mice but not in rats fed for 78 weeks. Rats were kept an additional 35 weeks and mice 13 weeks following treatment. Pheochromocytomas were also observed in mice. The doses fed were 92 and 46 mg/kg/ day for rats and 390 and 195 mg/kg/day for mice. Mortality was accelerated in female mice but not in the rats or male mice. The NCI report does not indicate the degree of noncarcinogenic histopathology produced by these doses.
In a bioassay conducted by NCI, technical-grade (92.7% pure) 1,1,2-trichloroethane was administered by gavage in corn oil to Osborne–Mendel rats and B6C3F1 mice: (50/species/sex/dose) for each of two doses and 20 animals/ species/sex for each of two control groups. Administration was five times/week for 78 weeks, during which time doses for rats were increased from 70 and 30 mg/kg/day to 100 and 50 mg/kg/day and doses for mice were increased from 300 and 150 mg/kg/day to 400 and 200 mg/kg/day. By two statistical tests, treatment of mice was found to be associated with increased incidence of hepatocellular carcinomas. A dose-related increase in pheochromocytomas was also confirmed in female mice. Tumors found in treated but not control rats included adrenal cortical carcinomas; transitional cell carcinomas of kidney; renal tubular adenomas; and hemangiosarcomas of spleen, pancreas, abdomen, and subcutaneous tissue. There was, however, no statistically significant increase in tumor incidence in rats as a function of treatment.
IRIS classifies this compound as C, possible human carcinogen on the basis of hepatocellular carcinomas and pheochromocytomas in one strain of mice. Carcinogenicity was not shown in rats. 1,1,2-Trichloroethane is structurally related to 1,2-dichloroethane, a probable human carcinogen. There are no human carcinogenicity data.

Environmental Fate

Biological. Vinyl chloride was reported to be a biodegradation product from an anaerobic digester at a wastewater treatment facility (Howard, 1990). Under aerobic conditions, Pseudomonas putida oxidized 1,1,2-trichloroethane to chloroacetic and glyoxylic acids. Simultaneously, 1,1,2-trichloroethane is reduced to vinyl chloride exclusively (Castro and Belser,1990). In a static-culture-flask screening test, 1,1,2-trichloroethane was statically incubated in the dark at 25 °C with yeast extract and settled domestic wastewater inoculum. Biodegradative activity was slow to moderate, concomitant with a significant rate of volatilization (Tabak et al., 1981).
Chemical/Physical. Products of hydrolysis include chloroacetaldehyde, 1,1-dichloroethylene, and HCl. The aldehyde is subject to hydrolysis forming hydroxyacetaldehyde and HCl (Kollig, 1993). The reported half-life for this reaction at 20 °C is 170 yr (Vogel et al., 1987). Under alkaline conditions, 1,1,2-trichloroethane hydrolyzed to 1,2-dichloroethylene. The reported hydrolysis half-life in water at 25 °C and pH 7 is 139.2 yr (Sata and Nakajima, 1979).

Shipping

UN3082 Environmentally hazardous substances, liquid, n.o.s., Hazard class: 9; Labels: 9-Miscellaneous hazardous material, Technical Name Required.

Purification Methods

Purify the chloroethane as for 1,1,1-trichloroethane above. [Beilstein 1 IV 139.]

Structure and conformation

1,1,2-Trichloroethane (TCE) is liquid at room temperature, and below 237 K, it displays a monoclinic phase, referred to as phase α, characterized by the simultaneous presence of distinct molecular conformers and orientations, accompanied by site disorder close to the melting point. At high pressure, a different monoclinic solid phase is observed (referred to as phase β), which at room temperature is stable above 0.82 GPa. Different conformers are present in the different phases of TCE. The gauche conformer is energetically more stable in isolation and by far the most abundant in the gas phase, where intermolecular interactions are negligible. Vibrational and NMR studies on the pure solvent have shown instead that in the liquid phase, the C2H3Cl3 molecules exist in both gauche and transoid conformations with comparable concentrations. Only transoid conformers are observed in the β crystalline phase (at high pressure)[1].

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong acids, strong caustics; chemically active metals;, such as aluminum, magnesium powders, sodium, potassium. Attacks some plastics, rubber, coatings, steel, and zinc.

Toxics Screening Level

The initial risk screening level (IRSL) for 1,1,2-trichloroethane (CAS #79-00-5) is 0.063 μg/m3 based on an annual averaging time.

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.

References

[1] Michela Romanini. “Simultaneous Orientational and Conformational Molecular Dynamics in Solid 1,1,2-Trichloroethane.” The Journal of Physical Chemistry C 122 10 (2018): 5774–5783.