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Vinyl chloride

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Properties

General

Name 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 Hazardous Chemical Database
SI units were used where possible. Unless otherwise stated, standard conditions were used.

Disclaimer and references

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.

Table of contents
1 History
2 Production
3 Uses
4 Health effects

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 While this method was widely used during the 1930's and 1940's, it has since been superseded by more economical processes.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

Typically, this reaction is conducted in a bath of boiling ethylene dichloride. When then heated to 500°C at 15-30 atm pressure, the ethylene dichloride decomposes to produce vinyl chloride and hydrogen chloride.

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 cupric chloride catalyst to produce even more ethylene dichloride via the reaction

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.