Chlorine (aka Chlorine Gas) is primarily produced by the electrolysis of sodium chloride, with a by-product of sodium chloride.
Chlorine is a poisonous gas and, for public safety, is produced on a JIT basis. Because sodium chloride is a by-product of chlorine production, an excess supply of chlorine can cause a shortage of sodium hydroxide (basically, if you have too much chlorine gas and no place to put it, you can't make sodium hydroxide).
Up Stream Materials/Building Blocks:
Sodium Hydroxide (Co-product relationship)
Down Stream Materials Consuming Chlorine:
The primary consumer of chlorine is Poly Vinyl Chloride (PVC). Demand for PVC (and availability of chlorine and sodium hydroxide) depends on the construction market.
Other downstream materials:
-Actyl decylmethyl ammonium chloride
-Alky dimethyl benzyl ammonium chloride
-Dioctyl dimethyl ammonium chloride