substance
Sodium hydroxide
Caustic soda solutions (e.g. 50 wt%) are a flow of this substance; the flow says its concentration.
- Formula
- NaOH
- CAS
- 1310-73-2
- InChIKey
- HEMHJVSKTPXQMS-UHFFFAOYSA-M
- ChEBI
- CHEBI:32145
Made by
- Chlor-alkali by membrane-cell electrolysis (100 kt/a Cl2, 50 wt-% caustic soda, hydrogen)Co-productConcept · not reviewed
Used by
- Acetone and phenol from cumene (cumene hydroperoxide route, 200 kt/a phenol)FeedstockConcept · not reviewed
- Alumina by the Bayer process (3000 t/d smelter-grade alumina, concept)FeedstockConcept · not reviewed
- Ethylene and propylene by ethane steam cracking (1000 kt/a ethylene, concept)FeedstockConcept · not reviewed
- Refined glycerol (USP) from biodiesel crude glycerol (10 000 t/a, concept)FeedstockConcept · not reviewed
- Iodine from natural iodide brine by chlorine oxidation, air blowing-out and SO2 absorption (1000 t/a)FeedstockConcept · not reviewed
- Bleached softwood kraft pulp with chemical recovery (1000 ADt/d market pulp, concept)FeedstockConcept · not reviewed
- N-Bromosuccinimide by semi-batch bromination of succinimide in aqueous NaOH (500 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
- Solid sodium cyanide from Andrussow HCN (6.25 t/h, 50 kt/a)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
- NaAlO2+2H2OgivesAl(OH)3+NaOHProduct · Seeded gibbsite precipitation · one process
- 2LIG+2NaOH+O2gives2NaOXL+2H2OReactant · Oxidative lignin dissolution in the O2 stage · one process
- SO2+2NaOHgivesNa2SO3+H2OReactant · one process
- 2NaOHgivesNa2O+H2OReactant · Occluded soda fixed as Na2O in the calciner · one process
- 3Al2Si2O5(OH)4+8NaOHgivesDSP+9H2OReactant · Desilication (kaolinite to sodalite-type desilication product) · one process
- 3CaH2O2+2NaAlO2+4H2OgivesCa3Al2(OH)12+2NaOHProduct · Lime in aluminate liquor to tricalcium aluminate · one process
- SOCl2+4NaOHgivesNa2SO3+2NaCl+2H2OReactant · one process
- 5CELL+24ClO2+24NaOHgives30CO2+24NaCl+37H2OReactant · Oxidation of carbohydrate by the ClO2 not used on lignin (yield loss) · one process
- 5LIG+2ClO2+2NaOHgives5OXL+2NaCl+H2OReactant · Lignin oxidation by chlorine dioxide (5 electrons per ClO2) · one process
- PCl3+5NaOHgivesNA2HPO3+3NaCl+2H2OReactant · one process
- 2Cl2S2+6NaOHgivesNa2S2O3+2S+4NaCl+3H2OReactant · one process
- 2Cl2S+6NaOHgivesNa2S2O3+4NaCl+3H2OReactant · one process
- POCl3+6NaOHgivesNa3PO4+3NaCl+3H2OReactant · one process
- Al(OH)3+NaOHgivesNaAlO2+2H2OReactant · Gibbsite digestion · one process
- C4H5NO2+NaOH+Br2givesC4H4BrNO2+NaBr+H2OReactant · Bromination of succinimide in aqueous NaOH · one process
- Na2CO3+CaH2O2givesCaCO3+2NaOHProduct · Causticizing · one process
- CELL+NaOHgivesNaISAReactant · Alkaline peeling of cellulose to isosaccharinate · one process
- CHN+NaOHgivesNaCN+H2OReactant · one process
- Cl2+2NaOHgivesNaCl+NaOCl+H2OReactant · 2 processes
- Na2SO3+Cl2+2NaOHgivesNa2SO4+2NaCl+H2OReactant · Chemical dechlorination with sulfite in alkaline brine · 2 processes
- CO2+2NaOHgivesNa2CO3+H2OReactant · Carbonation of residual alkali in the furnace · 2 processes
- COCl2+4NaOHgivesNa2CO3+2NaCl+2H2OReactant · one process
- EXTR+NaOHgivesNaEXT+H2OReactant · Saponification of extractives to resin soap · one process
- H2SO4+2NaOHgivesNa2SO4+2H2OReactant · Neutralisation of the sulfuric acid of the spent brine (R-401) · 3 processes
- NaOH+HClgivesNaCl+H2OReactant · Neutralisation of caustic and hydrochloric acid · 3 processes
- HEMI+NaOHgivesNaISAReactant · Alkaline dissolution and peeling of hemicellulose · one process
- HI+NaOHgivesNaI+H2OReactant · Neutralisation of the residual hydriodic acid of the spent brine (R-401) · one process
- LIG+NaOHgivesNaLIG+H2OReactant · Lignin dissolution as sodium lignate · one process
- MgCl2+2NaOHgivesMg(OH)2+2NaClReactant · Magnesium removal with caustic · one process
Routes compared
One route in the Atlas makes Sodium hydroxide: nothing to compare yet. A comparison appears when a second route is added.
Per 1 kg of Sodium hydroxide: 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 | a co-product of a multi-output dataset (product:CL2, product:H2 besides it): its share needs the allocation of the LCI database build | no footprint | – | ||
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.