Production of Polyvinylchloride

Introduction: Polyvinyl chloride (PVC) is a thermoplastic and is produced by polymerization of the monomer vinyl chloride. . It is produced in several steps.

1. Vinyl chloride is manufactured industrially from ethylene and chlorine. In the presence of iron(III) chloride as a catalyst, the compounds react to produce ethylene dichloride. CH2=CH2 + Cl2 → ClCH2CH2Cl
2. The reaction is then conducted in a bath of boiling ethylene dichloride. The reaction is known as thermal cracking or pyrolysis. When heated to 500 °C at 15–30 atmospheric (1.5 to 3 MPa) pressure, the ethylene dichloride decomposes to produce vinyl chloride and hydrogen chloride. ClCH2CH2Cl → CH2=CHCl + HCl
3. The vinyl chloride is then isolated.
4. Then, the hydrogen chloride produced is mixed with oxygen and reacted with ethylene on a copper(II) chloride catalyst to produce more ethylene dichloride. CH2=CH2 + 2 HCl + ½ O2 → ClCH2CH2Cl + H2O
5. Finally, Polyvinyl chrloride (PVC) is made by addition polymerization of the vinyl chloride, linking the molecules of a simple substance (monomer) together to form large molecules, without forming any other products.

Glossary:
Polymerization: The bonding of two or more monomers to form a polymer
Monomer: A molecule of low molecular weight capable of reacting with identical or different molecules of low molecular weight to form a polymer.