Chloroethane

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Chloroethane
Skeletal formula of chloroethane Skeletal formula of chloroethane with stereo bonds
Ball-and-stick model of chloroethane
Identifiers
CAS number 75-00-3 YesY
PubChem 6337
ChemSpider 6097 YesY
UNII 46U771ERWK YesY
KEGG D04088 YesY
ChEBI CHEBI:47554 YesY
ChEMBL CHEMBL46058 YesY
RTECS number KH7525000
ATC code N01BX01
Jmol-3D images Image 1
Properties
Molecular formula C2H5Cl
Molar mass 64.51 g mol−1
Appearance Colorless gas
Odor Pungent, ethereal[1]
Density 0.921 g/cm3 (0-4 °C)[2]
0.8898 g/cm3 (25 °C)
Melting point −138.7 °C (−217.7 °F; 134.5 K)
Boiling point 12.27 °C (54.09 °F; 285.42 K)
decomposes at 510 °C[4]
Solubility in water 0.447 g/100 mL (0 °C)
0.574 g/100 mL (20 °C)[3][4]
Solubility Soluble in alcohol, ether[5]
Solubility in ethanol 48.3 g/100 g (21 °C)[4]
Vapor pressure 8.4 kPa (-40 °C)
62.3 kPa (0 °C)[6]
134.6 kPa (20 °C)[1]
kH 11.1 L·atm/mol (24 °C)[1]
Refractive index (nD) 1.3676 (20 °C)
1.001 (25 °C)[1]
Viscosity 0.279 cP (10 °C)[1]
Structure
Dipole moment 2.06 D
Thermochemistry
Specific
heat capacity
C
104.3 J/mol·K[4]
Std molar
entropy
So298
190.8 J/mol·K[4]
Std enthalpy of
formation
ΔfHo298
-137 kJ/mol[6][4]
Gibbs free energy ΔG -59.3 kJ/mol[4]
Hazards
GHS pictograms The flame pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)The health hazard pictogram in the Globally Harmonized System of Classification and Labelling of Chemicals (GHS)[2]
GHS signal word Danger
GHS hazard statements H220, H280, H351, H412[2]
GHS precautionary statements P210, P273, P281, P410+403[2]
EU classification Extremely Flammable F+ Harmful Xn
R-phrases R12, R40, R52/53
S-phrases S9, S16, S33, S36/37, S61
Main hazards Flammable
NFPA 704
Flammability code 4: Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23 °C (73 °F). E.g., propane Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 2: Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water, or may form explosive mixtures with water. E.g., phosphorus Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point −43 °C (−45 °F; 230 K)
open cup[3]
−50 °C (−58 °F; 223 K)
closed cup[5][2]
Autoignition temperature 494–519 °C (921–966 °F; 767–792 K) [4][5]
Related compounds
Related haloalkanes 1,1-dichloroethane

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

Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
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Infobox references

Chloroethane or monochloroethane, commonly known by its old name ethyl chloride, is a chemical compound with chemical formula C
2
H
5
Cl
, once widely used in producing tetraethyllead, a gasoline additive. It is a colorless, flammable gas or refrigerated liquid with a faintly sweet odor.

Production[edit]

Chloroethane is produced by hydrochlorination of ethene:

C2H4 + HCl → C2H5Cl

At various times in the past, chloroethane has also been produced from ethanol and hydrochloric acid, or from ethane and chlorine, but these routes are no longer economical. Some chloroethane is generated as a byproduct of polyvinyl chloride production. Should demand for chloroethane 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[edit]

Beginning in 1922 and continuing through most of the 20th century, the major use of chloroethane 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 chloroethane has fallen sharply. It also reacts with aluminium metal to give ethylaluminium sesquichloride, a precursor to polymers and other useful organoaluminium compounds.[7]

Like other chlorinated hydrocarbons, chloroethane 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 chloroethane is in treating cellulose to make ethylcellulose, a thickening agent and binder in paints, cosmetics, and similar products.

Chloroethane 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.

Chloroethane 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".[8]

In dentistry, chloroethane 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. Chloroethane'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[edit]

Chloroethane 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 of 3% to 5%, victims usually exhibit symptoms similar to those of alcohol intoxication. Breathing its vapors at >15% concentration 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 exhibit shallow breathing, loss of consciousnesses, and depressed heart-rate. They can be aroused with physical contact or loud noise. At this point removal from the area of exposure is advised to restore consciousness. The long term effects of exposure over a period of 4 or more hours will cause side effects similar to alcoholic hang-over with dehydration, dizziness, loss of clear vision and temporary loss of consciousness, 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 vomit, which can lead to aspiration if the victim is not turned on his side. This constitutes a medical emergency and requires prompt action. It is advised to move the victim to clear air and administrator forced breathing for them to purge the lungs of the toxic fumes. If the victim recovers quickly enough, hospitalization may not be required, but will require a medical examination to ensure that no organ damage has occurred.

At >12% concentration, the victim's heart, lungs and kidneys begin to fail. Immediate CPR followed by medical support measures may be required to prevent fatal kidney,lung and heart failure.

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).[9]

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[edit]

  1. ^ a b c d e CID 6337 from PubChem
  2. ^ a b c d e Sigma-Aldrich Co., Chloroethane. Retrieved on 2014-05-26.
  3. ^ a b "Summary of Emissions Associated with Sources of Ethyl Chloride". http://nepis.epa.gov. National Service Center for Environmental Publications (NSCEP). Retrieved 2014-05-26. 
  4. ^ a b c d e f g h http://chemister.ru/Database/properties-en.php?dbid=1&id=1545
  5. ^ a b c "Material Safety Data Sheet". http://www.mathesongas.com. Matheson Tri-Gas, Inc. Retrieved 2014-05-26. 
  6. ^ a b Ethyl chloride in Linstrom, P.J.; Mallard, W.G. (eds.) NIST Chemistry WebBook, NIST Standard Reference Database Number 69. National Institute of Standards and Technology, Gaithersburg MD. http://webbook.nist.gov (retrieved 2014-05-26)
  7. ^ Krause, M.J., Orlandi, F., Saurage, A.T., Zietz Jr., J.R. Aluminum Compounds. Ullmann's Encyclopedia of Industrial Chemistry. 2000. doi:10.1002/14356007.a01_543
  8. ^ 1904 Brazilian advertisement
  9. ^ Chloroethane, IARC

External links[edit]