Dichloroethyne

Chemical Properties

DCA is a volatile, pyrophoric oil. It has an unpleasant, sweetish odor. A gas above 32°C/90°F.

Uses

DCA is not commercially available in large quantities. It is reportedly a by-product of the synthesis of vinylidene chloride and is not known to be used commercially.

Production Methods

DCA is a highly toxic, spontaneously combustible, undesired, and noncommercial product of the dehydrochlorination of trichloroethylene. It has resulted from exposure of trichloroethylene vapor to Hopcalite in a closed environmental system (submarine) and soda lime in closed circuit (rebreathing) anesthesia machines and from exposure of trichloroethylene liquid to caustic in degreaser tanks. It may also be an undesired by-product during chemical processes such as production of vinylidene chloride. When DCA was decomposed in the presence of oxygen, seven substanceswere found: phosgene, hexachlorobutadiene, chloroform, carbon tetrachloride, trichloroacetyl chloride, tetrachloroethylene, and trichloroacryloyl chloride.

General Description

Volatile oil with a disagreeable, sweetish odor. Mp: -68 to -65°C; bp: 32-34°C. Density: 1.38 g cm-3. Is not produced commercially.

Air & Water Reactions

Ignites or explodes upon contact with air (MCA Case History 1989 (1974)).

Reactivity Profile

Dichloroethyne is a reducing agent. Incompatible with oxidizing agents. Can ignite or explode on contact with air or if heated. Can explode if shocked. Burns in the presence of chlorine to form phosgene (Ann. Chem. 640:5(1961)).

Health Hazard

Dichloroacetylene is a neurotoxin; it is carcinogenic in experimental animals.

Potential Exposure

DCA, dichloroacetylene, is not produced commercially and is a possible decomposition product of trichloroethylene or trichloroethane. Reported to be a by-product of vinylidene chloride (see V:0220). Also, a closed circuit anesthesia with trichloroethylene, heat and moisture produced by soda-lime absorption of CO2 may produce dichloroacetylene (DCA) along with phosgene and carbon monoxide (CO).

Carcinogenicity

The IARC concluded that there is limited evidence for the carcinogenicity of DCA to experimental animals based on treatment-related increases in the incidence of adenocarcinomas of the kidney in male mice, benign tumors of the liver and kidney, and an increased incidence of lymphomas in rats.

Metabolic pathway

By the incubation of dichloroacetylene with rat liver and kidney subcellular fractions, the formation of S- (1,2-dichlorovinyl)glutathione (DCVG) is observed, and N-acetyl-S-(1,2-dichlorovinyl)-L-cysteine is identified as a urinary metabolite in rats.

Shipping

Explosive! Dichloroacetylene is cited by DOT as “FORBIDDEN.”

Incompatibilities

An unstable explosive; heat or shock may cause explosion. 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 (forms poisonous gases of phosgene and hydrogen chloride), strong bases.

Raw materials

Preparation Products