Ethyl chloride

Ethyl chloride

Chloroethane
Identifiers
CAS number 75-00-3 YesY
PubChem 6337
ChemSpider 6097 YesY
UNII 46U771ERWK YesY
KEGG D04088 YesY
ChEBI CHEBI:47554 YesY
RTECS number KH7525000
ATC code BX01
Jmol-3D images Image 1
Properties
Molecular formula C2H5Cl
Molar mass 64.51 g/mol
Appearance colourless gas
Density 0.92 g/cm3, liquid
Melting point

−139 °C (134 K)

Boiling point

12.3 °C (285.4 K)

Solubility in water 0.6 g/100 ml (?°C)
Structure
Dipole moment 2.06 D
Hazards
R-phrases R12, R40, R52, R53
S-phrases S9, S16, S33, S36, S37, S61
Main hazards Flammable
NFPA 704
4
2
2
Flash point −50°C (closed cup)
Related compounds
Related haloalkanes 1,1-dichloroethane

1,2-dichloroethane
1,1,1-trichloroethane
1,1,2-trichloroethane
bromoethane
chloromethane

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Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Chloroethane or monochloroethane, commonly known by its old name ethyl chloride, is a chemical compound with chemical formula , once widely used in producing tetraethyllead, a gasoline additive. It is a colorless, flammable gas or refrigerated liquid with a faintly sweet odor.

Production

Ethyl chloride is produced by hydrochlorination of ethylene:

C2H4 + HCl → C2H5Cl

At various times in the past, ethyl chloride has also been produced from ethanol and hydrochloric acid, or from ethane and chlorine, but these routes are no longer economical. Some ethyl chloride is generated as a byproduct of polyvinyl chloride production. Should demand for ethyl chloride continue to fall to the point where making it for its own sake is not economical, this may become the leading source of the chemical.

Uses

Beginning in 1922 and continuing through most of the 20th century, the major use of ethyl chloride was to produce tetraethyllead (TEL), an anti-knock additive for gasoline. TEL has been or is being phased out in most of the industrialized world, and the demand for ethyl chloride has fallen sharply. It also reacts with aluminium metal to give ethylaluminium sesquichloride, a precursor to polymers and other useful organoaluminium compounds.[1]

Like other chlorinated hydrocarbons, ethyl chloride has been used as a refrigerant, an aerosol spray propellant, an anesthetic, and a blowing agent for foam packaging. For a time it was used as a promoter chemical in the aluminium chloride catalyzed process to produce ethylbenzene, the precursor for styrene monomer. At present though, it is not widely used in any of these roles.

The only remaining industrially important use of ethyl chloride is in treating cellulose to make ethylcellulose, a thickening agent and binder in paints, cosmetics, and similar products.

Ethyl chloride is supplied as a liquid in a spray bottle propelled by its own vapor pressure. It acts as a mild topical anesthetic by its chilling effect when sprayed on skin, such as when removing splinters in a clinical setting. The heat absorbed by the boiling liquid on tissues produces a deep and rapid chill, but since the boiling point is well above the freezing point of water, it presents no danger of frostbite. The vapor is flammable and narcotic, which requires care.

Ethyl chloride is a recreational inhalant drug, sometimes referred to as "Duster". Similar to poppers, ethyl chloride is used as an inhalant (huffed) during sexual activity. In Brazil, it is a traditional (though illegal) drug taken during Carnaval parades, known as "lança-perfume".[2]

In dentistry, ethyl chloride is used as one of the means of diagnosing a 'dead tooth', i.e. one in which the pulp has died. A small amount of the substance is placed on the suspect tooth using a cotton wad. Ethyl chloride's low boiling point creates a localised chilling effect. If the tooth is still alive this should be sensed by the patient as mild discomfort that subsides when the wad is removed.

Safety

Ethyl chloride is the least toxic of the chloroethanes. Like other chlorinated hydrocarbons, it is a central nervous system depressant, albeit a less potent one than many similar compounds. People breathing its vapors at less than 1% concentration in air usually experience no symptoms. At concentrations like 3% to 5%, victims usually exhibit symptoms similar to those of alcohol intoxication. Breathing its vapors at 15% or higher is often fatal but most commercially available handheld containers contain a total of 30% per volume of concentrated vapors which naturally disperse in the outside air.

If exposed to concentrations higher than 6% to 8% victims often have shallow breathing, lose consciousnesses, and their heart-rate drops a little bit to the more relaxed state, they can be aroused with physical contact or loud noises. At this point removal from the area of exposure is advised so as to force consciousness back to the victim. The long term effects of exposure over a period of four or more hours will cause side effects similar to alcoholic hang-over with dehydration, dizziness, lose of clear vision, and temporary coma-states which can last an hour or more. If no longer exposed to the gas a victim will return to normal health quickly; this can be helped with intake of extra fluids, vitamins, and sugars.

Toxic over-exposure starts at 9% to 12% concentrations, the heart rate drops further, the victim may have more shallow breathing or stop all together, they do not respond to any outside stimulation and may begin to involuntarily gasp, belch, or vomiting which can lead to aspiration if they do not get turned on their sides. This is a medical emergency situation and requires prompt action, it is advised to move the victim to clear air and administrator forced breathing for them to help clear the lungs of the toxic fumes. If the victim recovers quickly enough, they may not require hospitalization but will require a medical prognosis to ensure no organ damage occurred.

At anything over 12% the victim's heart, lungs, and kidneys start to fail, they require immediate CPR and hospitalization with in the first 10 minutes otherwise their kidneys, lungs, and heart will cease functioning.

Studies on the effects of chronic ethyl chloride exposure in animals have given inconsistent results, and no data exists for its long-term effects on humans. Some studies have reported that prolonged exposure can produce liver or kidney damage, or uterine cancer in mice, but these data have been difficult to reproduce.

Chloroethane is not classifiable as to its carcinogenicity to humans (Group 3).[3]

Recent information suggests carcinogenic potential; it has been designated as ACGIH category A3, Confirmed Animal Carcinogen with Unknown Relevance to Humans. As a result, the State of California has incorporated it into Proposition 65 as a known carcinogen. Nonetheless, it is still used in medicine as a local anesthetic.

References

External links

  • International Chemical Safety Card 0132
  • Pocket Guide to Chemical Hazards 0267
  • Chloroethane."
  • http://webbook.nist.gov
  • National Pollutant Inventory - Chloroethane