SODIUM SULPHITE

Sodium Sulphite is an inorganic sulfite salt used widely as an antioxidant, reducing agent, oxygen scavenger, and preservative support ingredient in food, beverage, pharmaceutical, and industrial processes.
Sodium Sulphite is valued because Sodium Sulphite reacts readily with dissolved oxygen and oxidizing species, and Sodium Sulphite helps prevent oxidative discoloration, off-odors, and degradation of sensitive ingredients in compatible systems.
Sodium Sulphite must be handled with care because Sodium Sulphite dust can irritate eyes and respiratory tract, and sulfites can trigger allergic or asthma-like reactions in sensitive individuals, so Sodium Sulphite use requires appropriate hygiene, labeling compliance, and exposure control.

CAS Number: 7757-83-7
EC Number: 231-821-4
Molecular Formula: Na2SO3
Molecular Weight: 126.04 g/mol

Synonyms: Sodium Sulphite, Sodium Sulfite (US spelling), Na2SO3, Sulfurous Acid Disodium Salt (common naming), Sodium Sulphite Anhydrous, Sodium Sulphite Powder, Sodium Sulphite Reducing Agent, Sodium Sulphite Oxygen Scavenger, Sodium Sulphite Antioxidant, Sodium Sulphite Dechlorination Agent, Sodium Sulphite Process Chemical, Sodium Sulphite Technical Grade, Sodium Sulphite, Sodium Sulfite, Disodium Sulphite, Disodium Sulfite, Sulphurous Acid Disodium Salt, Sulfurous Acid Disodium Salt, Sulphite of Soda, Sulfite of Soda, Sodium Sulphite Anhydrous, Sodium Sulfite Anhydrous, Sodium Sulphite Solution, Sodium Sulfite Solution, Sodium Sulphite Reagent, Sodium Sulfite Reagent, Sodium Sulphite Technical Grade, Sodium Sulfite Technical Grade, Sodium Sulphite Industrial Grade, Sodium Sulfite Industrial Grade, Sodium Sulphite Food Grade, Sodium Sulfite Food Grade, Sodium Sulphite Pharmaceutical Grade, Sodium Sulfite Pharmaceutical Grade, Sodium Sulphite Preservative, Sodium Sulfite Preservative, Sodium Sulphite Antioxidant, Sodium Sulfite Antioxidant, Sodium Sulphite Reducing Agent, Sodium Sulfite Reducing Agent, Sodium Sulphite Oxygen Scavenger, Sodium Sulfite Oxygen Scavenger, Sodium Sulphite Dechlorinating Agent, Sodium Sulfite Dechlorinating Agent, Sodium Sulphite Water Treatment Grade, Sodium Sulfite Water Treatment Grade, Sodium Sulphite FCC, Sodium Sulfite FCC, Sodium Sulphite USP, Sodium Sulfite USP, Sodium Sulphite BP, Sodium Sulfite BP, Sodium Sulphite EP, Sodium Sulfite EP, Sodium Sulphite NF, Sodium Sulfite NF, Sodium Sulphite ACS, Sodium Sulfite ACS, Sodium Sulphite Analytical Grade, Sodium Sulfite Analytical Grade, Sodium Sulphite Laboratory Grade, Sodium Sulfite Laboratory Grade, Sodium Sulphite Food Additive, Sodium Sulfite Food Additive, Sodium Sulphite E221, Sodium Sulfite E221, E221, INS 221, Na2SO3, Na₂SO₃, Sodium Sulphite Na2SO3, Sodium Sulfite Na2SO3, Monosodium Sulphite, Monosodium Sulfite, Neutral Sodium Sulphite, Neutral Sodium Sulfite, Sulphurous Acid Sodium Salt, Sulfurous Acid Sodium Salt, Sodium Sulphite Powder, Sodium Sulfite Powder, Aqueous Sodium Sulphite, Aqueous Sodium Sulfite

APPLICATIONS

Sodium Sulphite is used in water treatment as an oxygen scavenger to reduce dissolved oxygen and protect boilers and pipelines from corrosion.
Sodium Sulphite is incorporated into boiler water treatment programs to reduce oxidative corrosion risk in steam systems.
Sodium Sulphite is used in closed-loop water systems where deoxygenation improves equipment lifetime and reliability.

Sodium Sulphite is used in water treatment as a dechlorination agent to neutralize residual chlorine and protect downstream processes.
Sodium Sulphite is incorporated into wastewater treatment to quench chlorine before discharge when permitted and controlled.
Sodium Sulphite is used in membrane and resin protection strategies where chlorine removal prevents damage.

Sodium Sulphite is used in pulp and paper processing as a reducing agent and bleaching support chemical in compatible pulping and deinking processes.
Sodium Sulphite is incorporated into paper recycling and deinking operations to improve brightness and reduce ink-related color bodies.
Sodium Sulphite is used in specialty bleaching steps where sulfite chemistry provides controlled reduction.

Sodium Sulphite is used in textile processing as a reducing agent in dyeing and printing to control color development and remove excess dye.
Sodium Sulphite is incorporated into dye baths to reduce oxidative side reactions and improve shade consistency.
Sodium Sulphite is used in textile finishing to support bleaching and color stripping operations in compatible systems.

Sodium Sulphite is used in food processing as an antioxidant and preservative support agent in applications where sulfites are permitted and labeling is managed.
Sodium Sulphite is incorporated into dried fruit processing and potato processing to reduce browning and oxidative discoloration in compatible operations.
Sodium Sulphite is used in seafood processing in some markets to support anti-browning and quality preservation when regulations permit.

Sodium Sulphite is used in beverage processing as an antioxidant and oxygen scavenger in compatible products and process steps.
Sodium Sulphite is incorporated into fermentation-adjacent processing to reduce oxidative stress in sensitive ingredients where allowed.
Sodium Sulphite is used in syrup and concentrate processing to protect flavor and color from oxidation when permitted by food rules.

Sodium Sulphite is used in pharmaceutical manufacturing as a reducing agent and antioxidant in compatible formulations to protect APIs from oxidation.
Sodium Sulphite is incorporated into injectable and oral products only when appropriate quality, stability, and regulatory requirements are met.
Sodium Sulphite is used in excipient and reagent roles where oxygen scavenging improves product stability.

Sodium Sulphite is used in photographic processing in some legacy systems as a preservative and reducing agent for developing solutions.
Sodium Sulphite is incorporated into developer formulations to reduce oxidation and extend solution life.
Sodium Sulphite is used in laboratory chemistry as a reducing agent and oxygen scavenger for controlled reactions.

Sodium Sulphite is used in chemical manufacturing as a reducing agent and as a precursor for sodium bisulfite and sodium metabisulfite production.
Sodium Sulphite is incorporated into sulfite/bisulfite chemistry where controlled sulfur(IV) species are required.
Sodium Sulphite is used in industrial cleaning and processing where oxygen removal and reduction improve process stability.

Sodium Sulphite is valued because Sodium Sulphite provides effective reduction and oxygen scavenging for many processes, but Sodium Sulphite use requires careful control for safety, allergen labeling, and compatibility.

DESCRIPTION

Sodium Sulphite is a white crystalline powder that dissolves in water to form sulfite ions, and sulfite can equilibrate with bisulfite depending on pH.
Sodium Sulphite acts as a reducing agent by consuming dissolved oxygen and oxidizing species, and this helps protect sensitive compounds from oxidative degradation.
Sodium Sulphite can generate sulfur dioxide in acidic conditions, so Sodium Sulphite solutions should be handled with ventilation and pH control to avoid SO2 release.

Sodium Sulphite can be oxidized to sodium sulfate during storage and use, especially in the presence of air and moisture, so sealed storage and controlled dosing help maintain performance.
Sodium Sulphite dust can irritate eyes and respiratory tract, and sensitive individuals can react to sulfites, so exposure control and allergen communication are important.
Sodium Sulphite should be kept away from strong oxidizers, and Sodium Sulphite should not be mixed with acids unless controlled reaction is intended.

Sodium Sulphite should be stored in tightly closed containers in a cool, dry place to minimize oxidation and caking.
Sodium Sulphite should be used according to applicable regulations and specifications for the intended market and product category.
Sodium Sulphite waste and solutions should be disposed of according to local regulations and facility procedures.

PROPERTIES

Chemical Formula: Na2SO3
Molecular Weight: 126.04 g/mol
Common Name: Sodium Sulphite (Sodium Sulfite)
Chemical Type: Inorganic sulfite salt; reducing agent; oxygen scavenger
Appearance: White crystalline powder
Odor: Odorless
Solubility: Soluble in water; forms sulfite and bisulfite equilibria depending on pH
Reactivity: Reducing agent; reacts with oxygen; releases SO2 under acidic conditions; incompatible with strong oxidizers
pH Behavior: Alkaline to neutral solutions; bisulfite formation increases at lower pH
Stability: Oxidizes to sodium sulfate over time, especially with air and moisture exposure
Health Considerations: Dust irritant; sulfite sensitivity possible; manage exposure and labeling
Storage Temperature: 10–25°C, dry, tightly closed
Shelf Life: Typically 24–36 months in original sealed packaging (supplier dependent)

FIRST AID

Inhalation:
Move to fresh air if dust is inhaled.
Seek medical attention if respiratory irritation persists.
Monitor sensitive individuals for asthma-like reactions.

Skin Contact:
Wash with soap and water after contact.
Remove contaminated clothing and wash before reuse.
Seek medical advice if irritation develops or persists.

Eye Contact:
Rinse cautiously with water for several minutes.
Remove contact lenses if present and easy to do, then continue rinsing.
Seek medical attention if irritation persists.

Ingestion:
Rinse mouth with water.
Seek medical attention if discomfort occurs or if a significant amount is swallowed.
Never give anything by mouth to an unconscious person.

Note to Physicians:
Treat symptomatically.
Consider sulfite sensitivity and bronchospasm risk in susceptible individuals.
Provide supportive care based on exposure route and symptoms.

HANDLING AND STORAGE

Handling:
Use appropriate PPE including gloves and safety glasses, and use dust protection as needed.
Avoid generating dust and avoid inhalation of fine powder.
Do not mix with acids unless the process is designed and ventilated because SO2 can be released.

Ventilation:
Use local exhaust or general ventilation where dust may be generated.
Maintain good airflow during weighing, charging, and blending operations.
Avoid enclosed spaces where SO2 could accumulate if acid contact occurs.

Storage:
Store in tightly closed containers in a cool, dry place.
Protect from moisture and air exposure to reduce oxidation to sulfate and prevent caking.
Keep away from strong oxidizers and store away from acids.

Spill and Leak Procedures:
Sweep up spilled material and avoid dust generation.
Collect into suitable containers for reuse or disposal according to local regulations.
Clean residues with wet wiping if needed to reduce airborne dust.

Handling Precautions:
Control pH in solutions to minimize SO2 release and to maintain desired sulfite/bisulfite balance.
Implement allergen and sensitivity awareness where Sodium Sulphite is used in food or consumer products.
Rotate stock using FIFO practices to maintain consistent reducing performance and product quality.