substance

Chlorine

Formula: Cl2
CAS: 7782-50-5
InChIKey: KZBUYRJDOAKODT-UHFFFAOYSA-N
ChEBI: CHEBI:29310

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Made by

Chlor-alkali by membrane-cell electrolysis (100 kt/a Cl2, 50 wt-% caustic soda, hydrogen)Main productConcept · not reviewed

Used by

Bromine from bromide brine by chlorine oxidation and steaming-out (Smackover-type brine)FeedstockConcept · not reviewed
Hydrogen chloride synthesis burner and absorption (33 wt-% hydrochloric acid, steam recovery)FeedstockConcept · not reviewed
Iodine from natural iodide brine by chlorine oxidation, air blowing-out and SO2 absorption (1000 t/a)FeedstockConcept · not reviewed
Phosgene from CO and chlorine over activated carbon (17.3 t/h liquid phosgene, captive)FeedstockConcept · not reviewed
Phosphorus oxychloride from white phosphorus, chlorine and oxygen via PCl3 (4.0 t/h)FeedstockConcept · not reviewed
Thionyl chloride from sulfur, chlorine and SO2 over activated carbon (3.75 t/h)FeedstockConcept · not reviewed

Takes part in

2NaCl+2H₂OgivesCl₂+H₂+2NaOHProduct · Chlor-alkali electrolysis (overall cell reaction) · one process
H₂+Cl₂in equilibrium with2HClReactant · Hydrogen chloride synthesis (chlorine burnt in hydrogen) · one process
Cl₂S₂+Cl₂in equilibrium with2Cl₂SReactant · one process
Cl₂S+SO₂+Cl₂in equilibrium with2SOCl₂Reactant · one process
P₄+6Cl₂gives4PCl₃Reactant · Chlorination of white phosphorus · one process
Cl₂+SO₂+2H₂Ogives2HCl+H₂SO₄Reactant · Reduction of the blown-out excess chlorine by sulfur dioxide (T-202) · one process
2HI+Cl₂gives2HCl+I₂Reactant · Liberation of iodine from the recycled hydriodic acid (R-101) · one process
2NaBr+Cl₂gives2NaCl+Br₂Reactant · Oxidation of bromide by chlorine (bromine liberation) · one process
Cl₂+2NaOHgivesNaCl+NaOCl+H₂OReactant · 2 processes
2NaI+Cl₂gives2NaCl+I₂Reactant · Liberation of iodine from the brine iodide by chlorine (R-101) · one process
2S+Cl₂givesCl₂S₂Reactant · one process
CO+Cl₂in equilibrium withCOCl₂Reactant · one process
H₂S+Cl₂givesS+2HClReactant · Side reaction - oxidation of the brine's hydrogen sulfide by chlorine to sulfur · one process
Na₂SO₃+Cl₂+2NaOHgivesNa₂SO₄+2NaCl+H₂OReactant · Chemical dechlorination with sulfite in alkaline brine · 2 processes

Routes compared

One route in the Atlas makes Chlorine: nothing to compare yet. A comparison appears when a second route is added.

Per 1 kg of Chlorine: inventory from each route's LCI dataset, unallocated; footprints per the functional unit of their own LCA.

Route	Tier, design maturity, review status	Geography, year	Energy	Feedstocks	Key emissions	Footprint	Comparability
Chlor-alkali by membrane-cell electrolysis (100 kt/a Cl2, 50 wt-% caustic soda, hydrogen)bipolar membrane-cell NaCl electrolysis, 100 kt/a Cl2, rock salt with brine recirculation, 3.0 V at 6.0 kA/m2, double-effect caustic evaporation to 50 wt-%	flowsheet or hand-writtenDesign maturity: Concept (research)Not independently reviewedDataset review: unreviewed	GLO, 2026	Electric power (AC, grid): 2.58 kWh MP steam 1000 kPa(a): 0.544 kWh	Rock salt: 1.7 kg Make-up process water: 0.922 kg Demineralised water: 1.12 kg Soda ash: 0.00763 kg Hydrochloric acid 32 wt-%: 0.0336 kg Sodium sulfite: 0.000273 kg Sulfuric acid 98 wt-%: 0.0189 kg	CO2 to the environment: 0.00234 kg Na2SO4 to the environment: 0.0029 kg NaCl to the environment: 0.0574 kg	not published	–

ISO 14044 requires a critical review (by a panel of interested parties, ISO/TS 14071) of a comparative assertion intended to be disclosed to the public. These routes are listed side by side for screening; a statement that one is better than another needs that review. None of these routes has had such a review.