# Chlorine: Relationships Source page: https://www.materialinsights.org/chemicals/chlorine/links/ Every element and industry that Chlorine is linked to, and how. Each pair has its own card explaining the relationships between the two. - [Caustic soda](https://www.materialinsights.org/links/caustic-soda-and-chlorine/): Chlorine and caustic soda come out of the same brine electrolysis in a fixed ratio of about 1.1 t of caustic per tonne of chlorine, so neither can be made alone. Plants run for whichever product is in demand and the other's price absorbs the imbalance; electricity is the largest cost of both. *(researched)* - [Energy-intensive industry](https://www.materialinsights.org/links/chlorine-and-energy-intensive-industry/): Chlorine is made by electrolysis of brine, which puts chlor-alkali among the energy-intensive industries: electricity was about 60% of its manufacturing cost in India in 2021, so power prices set where chlorine can be made. *(researched)* - [Hydrogen](https://www.materialinsights.org/links/chlorine-and-hydrogen/): Every tonne of chlorine made by brine electrolysis brings about 30 kg of hydrogen, so chlor-alkali plants are a small but steady source of electrolytic hydrogen whose volume follows chlorine demand. Plants burn it as fuel, combine it with chlorine to make hydrochloric acid, turn it into hydrogen peroxide, or sell it. *(researched)* - [Polyurethanes (MDI, TDI, polyols)](https://www.materialinsights.org/links/chlorine-and-polyurethanes-mdi-tdi-polyols/): MDI and TDI, the isocyanate half of polyurethanes, are made with phosgene from chlorine and carbon monoxide. The chlorine does not stay in the foam: it leaves as hydrogen chloride, which plants recycle to chlorine or sell, so isocyanate complexes are built beside chlor-alkali or HCl recovery units. *(researched)* - [Salt](https://www.materialinsights.org/links/chlorine-and-salt/): Almost all chlorine is made from salt: electrolysing brine yields chlorine together with caustic soda, using about 1.65 tonnes of salt per tonne of chlorine in theory. Chlor-alkali makers are India's major industrial salt users, yet salt prices hardly affect chlorine, because salt is cheap and power is the main cost. *(researched)* - [Titanium dioxide](https://www.materialinsights.org/links/chlorine-and-titanium-dioxide/): The chloride route to titanium dioxide chlorinates titanium feed into titanium tetrachloride and then burns it back to pigment, recovering most of the chlorine for reuse, so only make-up chlorine is bought. About half of world pigment is made this way, but in China, the largest producer, the sulphate route, which uses sulphuric acid instead of chlorine, still dominates. *(researched)* - [Water and sanitation](https://www.materialinsights.org/links/chlorine-and-water-and-sanitation/): Chlorine is the standard disinfectant for piped water because it leaves a residual that keeps protecting water in the pipes, so water utilities treat it as a non-negotiable input; because chlorine is bought from nearby plants, a single outage can leave utilities short within weeks, as in the US Pacific Northwest in 2021. *(researched)* - [Epoxy resins](https://www.materialinsights.org/links/chlorine-and-epoxy-resins/): Their prices have moved together. - [Fluorochemicals and refrigerants](https://www.materialinsights.org/links/chlorine-and-fluorochemicals-and-refrigerants/): Their prices have moved together. - [Healthcare services](https://www.materialinsights.org/links/chlorine-and-healthcare-services/): Healthcare services depends on chlorine. - [Herbicides](https://www.materialinsights.org/links/chlorine-and-herbicides/): Their prices have moved together. - [Hospitality and tourism](https://www.materialinsights.org/links/chlorine-and-hospitality-and-tourism/): Hospitality and tourism depends on chlorine. - [Household and personal care](https://www.materialinsights.org/links/chlorine-and-household-and-personal-care/): Household and personal care depends on chlorine. - [Hydrochloric acid](https://www.materialinsights.org/links/chlorine-and-hydrochloric-acid/): Their prices have moved together. - [Insecticides](https://www.materialinsights.org/links/chlorine-and-insecticides/): Their prices have moved together. - [PVC](https://www.materialinsights.org/links/chlorine-and-pvc/): Their prices have moved together. - [Paper and packaging](https://www.materialinsights.org/links/chlorine-and-paper-and-packaging/): Paper and packaging depends on chlorine. - [Polycarbonate](https://www.materialinsights.org/links/chlorine-and-polycarbonate/): Their prices have moved together. - [Propylene oxide](https://www.materialinsights.org/links/chlorine-and-propylene-oxide/): Their prices have moved together. - [Public administration, defence and security](https://www.materialinsights.org/links/chlorine-and-public-administration-defence-and-security/): Public administration, defence and security depends on chlorine. - [Titanium](https://www.materialinsights.org/links/chlorine-and-titanium/): Their prices have moved together. - [Vinyl chloride monomer](https://www.materialinsights.org/links/chlorine-and-vinyl-chloride-monomer/): Their prices have moved together. - [Water](https://www.materialinsights.org/links/chlorine-and-water/): Their prices have moved together. - [Water treatment chemicals](https://www.materialinsights.org/links/chlorine-and-water-treatment-chemicals/): Their prices have moved together. - [Wholesale and retail trade](https://www.materialinsights.org/links/chlorine-and-wholesale-and-retail-trade/): Wholesale and retail trade depends on chlorine. ## Other sections - [Summary](https://www.materialinsights.org/chemicals/chlorine/index.md) - [Overview](https://www.materialinsights.org/chemicals/chlorine/overview/index.md) - [Correlation](https://www.materialinsights.org/chemicals/chlorine/correlation/index.md) - [Production route](https://www.materialinsights.org/chemicals/chlorine/routes/index.md) - [Production](https://www.materialinsights.org/chemicals/chlorine/production/index.md) - [Feedstocks](https://www.materialinsights.org/chemicals/chlorine/feedstocks/index.md) - [Cycles](https://www.materialinsights.org/chemicals/chlorine/cycles/index.md) - [Trading](https://www.materialinsights.org/chemicals/chlorine/trading/index.md) - [Movement](https://www.materialinsights.org/chemicals/chlorine/movement/index.md) - [Regulation](https://www.materialinsights.org/chemicals/chlorine/regulation/index.md) - [Characteristics](https://www.materialinsights.org/chemicals/chlorine/characteristics/index.md) - [Emissions](https://www.materialinsights.org/chemicals/chlorine/emissions/index.md)