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