Dichloroethyne

Description

DCA is a volatile oil. It has a disagreeable,sweetish odor. A gas above 32℃/90°F. Molecularweight = 94.92; Boiling point =32℃ (explodes); Freezing/Melting point=250℃ to 266℃. Hazard Identification(based on NFPA-704 M Rating System): Health 3,Flammability 0, Reactivity 0. Insoluble in water

Chemical properties

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

The Uses of Dichloroethyne

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.

The Uses of Dichloroethyne

By-product in synthesis of vinylidene chloride; decomposition product of trichloroethylene under alkaline conditions

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.

Definition

ChEBI: Dichloroacetylene is an organochlorine compound.

Synthesis Reference(s)

The Journal of Organic Chemistry, 52, p. 3461, 1987 DOI: 10.1021/jo00391a059

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.

Safety Profile

Confirmed carcinogen with experimental carcinogenic data. Poison by inhalation. Central nervous system effects. Can be formed by thermal decomposition (>70℃) from trichloroethylene. Symptoms include a disabling nausea and intense jaw pain. Strong explosive when shocked or exposed to heat or air. Can react vigorously with oxidizing materials. When heated to decomposition or on contact with acid or acid fumes it emits highly toxic fumes of Cl-. See also ACETYLENE COMPOUNDS and CHLORINATED HYDROCARBONS , ALIPHATIC.

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).

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith 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 ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.Medical observation is recommended for 2448 h afterbreathing overexposure, as pulmonary edema may bedelayed. As first aid for pulmonary edema, a doctor orauthorized paramedic may consider administering a corticosteroid spray.

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.

storage

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with DCA youshould be trained on its proper handling and storage.Dichloroacetylene must be stored to avoid contact with oxidizers (such as perchlorates, peroxides, permanganates,chlorates, and nitrates) since violent reactions occur. Keepdichloroacetylene away from strong acids (such as hydrochloric, sulfuric, and nitric) because poisonous gasesmay be given off, including phosgene and hydrogen chloride. Store in tightly closed containers in a cool, well-ventilated area away from heat, potassium, sodium, andaluminum powders. Sources of ignition, such as smokingand open flames are prohibited where dichloroacetylene isused, handled, or stored in a manner that could create apotential fire or explosion hazard. Use only nonsparkingtools and equipment, especially when opening and closingcontainers of dichloroacetylene. Wherever dichloroacetylene is used, handled, manufactured, or stored, use explosion-proof electrical equipment and fittings. A regulated,marked area should be established where this chemical ishandled, used, or stored in compliance with OSHAStandard 1910.1045.

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.