Vinyl chloride
Vinyl chloride, chloroethene
| Chemical formula |
CH2=CHCl |
| Appearance |
Colorless gas |
|
Physical
|
| Formula weight |
62.5 amu |
| Melting point |
119 K (-154 °C) |
| Boiling point |
259 K (-13 °C) |
| Density |
0.91 ×103 kg/m3 (liquid) |
| Solubility |
insoluble in water |
|
Thermochemistry
|
| ΔfH0gas |
-28.45 kJ/mol |
| ΔfH0liquid |
? kJ/mol |
| ΔfH0solid |
? kJ/mol |
| S0gas, 1 bar |
? J/mol·K |
| S0liquid, 1 bar |
? J/mol·K |
| S0solid |
? J/mol·K |
|
Safety
|
| Ingestion |
May cause nausea, vomiting, severe stomach pain. |
| Inhalation |
Can cause dizziness, drowsiness, confusion, unconsciousness, and respiratory failure. Long-term effects such as asthma may result. |
| Skin |
Frostbite and irritation can result from skin contact with the refrigerated liquid. |
| Eyes |
Possible irritant. |
| More info |
|
|
SI units were used where possible. Unless otherwise stated, standard conditions were used.
Disclaimer and references
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Vinyl chloride, also known as
chloroethene, is an important industrial chemical chiefly used to produce its
polymer,
polyvinyl chloride (PVC). At room temperature, it is a toxic, colorless gas with a sweet odor.
History
Vinyl chloride was first produced in 1835 by Justus von Liebig and his student Henri Victor Regnault. They obtained it by treating ethylene dichloride with a solution of potassium hydroxide in ethanol.
In 1912, Fritz Klatte, a German chemist working for Griesheim-Elektron, patented a means to produce vinyl chloride from acetylene and hydrogen chloride using mercuric chloride as a catalyst. While this method was widely used during the 1930's and 1940's, it has since been superseded by more economical processes.
Production
Vinyl chloride is manufactured on the industrial scale from ethylene and chlorine. In the presence of ferric chloride as a catalyst, these compounds react to produce ethylene dichloride according to the chemical equation
- CH2=CH2 + Cl2 → ClCH2CH2Cl → CH2=CHCl + HCl
In industrial practice, the hydrogen chloride produced in this step is mixed with oxygen and then reacted with additional ethylene on a CH2=CH2 + 2 HCl + ½ O2 → ClCH2CH2Cl + H2O
The hydrogen chloride consumed in this step exactly balances that produced in the second step, and the resulting balanced process neither requires hydrogen chloride as an input nor produces it as a waste. Due to the economical advantages of this process, most vinyl chloride has been produced via this technique since the late 1950's.
Uses
By far the most important use of vinyl chloride is its polymerization to make PVC. Much smaller amounts are used to produce other chlorinated hydrocarbons including ethylidene chloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and vinylidene chloride.
Vinyl chloride's toxicity limits its use in consumer goods.
Health effects
Vinyl chloride depresses the central nervous system, and inhaling its vapors produces symptoms similar to intoxication. These include headache, dizziness, and loss of coordination, and in severe cases may progress to hallucination, unconsciousness, and death by respiratory failure.
In laboratory animals, exposure to vinyl chloride during pregnancy has produced miscarriages and birth defects. Its effect on human reproduction is unknown.
Long-term exposure to vinyl chloride can cause chronic skin irritations and has also been linked to a painful inflammation of the extremities called Raynaud's syndrome. Vinyl chloride is considered to be a
carcinogen and has in particular been linked to certain
cancers of the
liver.
