Sodium Dithionite

Faint sulfurous

Slight characteristic odor

2.38 g/cu cm

Na2S2O4.2H2O, mol wt 210.146 ... crystallizes in thin, yellowish shiny, soft prisms of density 1.58 g/cu cm /Dihydrate/

2.4 g/m³

White or grayish-white crystalline powder

Light-lemon-colored solid in powder or flake form

White, colorless or yellow-white crystals

Slightly sol in alcohol; very soluble in water

Slightly sol in cold water; insoluble in acids

At 20 °C, 24.1 g/100 g water

Solubility in water, g/100ml at 20 °C: 25 (moderate)

about 100 °C (open cup)

>100 °C o.c.

A batch decomposed violently during drying in graining bowl. No explanation was offered but contamination with water and/or oxidant seems likely. Thermal decomposition occurs violently at 190 °C.

>100 °C

Sodium dithionite is a whitish to light yellow crystalline solid having a sulfur dioxide-like odor. It spontaneously heats on contact with air and moisture. This heat may be sufficient to ignite surrounding combustible materials. Under prolonged exposure to fire or intense heat containers of this material may violently rupture. It is used in dyeing and to bleach paper pulp.

Liquid; Other Solid; Dry Powder

White to grayish-white granular powder with a sulfur dioxide odor; [CHEMINFO MSDS]

Solid

WHITE CRYSTALLINE POWDER.

Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed. Keep away from combustible material.

Oxidizes in air, (more readily so in presence of moisture or when in solution) to bisulfite and bisulfate and acquires an acid reaction.

Sodium dithionite is not stable under physiological conditions, with the rate of decomposition increasing with increasing acidity. Upon contact with moisture, it is oxidized to hydrogen sulfite, sulfite and hydrogen sulfate, and under strongly acidic conditions it may liberate sulfur dioxide.

Strong reducing agent; also available in liquid form

Decomposes violently when heated to 190 °C and emits toxic fumes of SOx and Na2O.

Danger

H251: Self-heating; may catch fire [Danger Self-heating substances and mixtures]；H302: Harmful if swallowed [Warning Acute toxicity, oral]

P235, P264, P270, P280, P301+P317, P330, P407, P410, P413, P420, and P501 (click each P-code to see the statement)

Danger

Water-reactive material (WR)

Water-reactive material (WR)

Chemical: Dithionous acid, disodium salt

Dithionous acid, sodium salt (1:2) is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Dithionous acid, sodium salt (1:2) are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 01-02-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/15288

Dithionous acid, disodium salt: Does not have an individual approval but may be used under an appropriate group standard

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:；Flammable/combustible material. May ignite on contact with moist air or moisture. May burn rapidly with flare-burning effect. Some react vigorously or explosively on contact with water. Some may decompose explosively when heated or involved in a fire. May re-ignite after fire is extinguished. Runoff may create fire or explosion hazard. Containers may explode when heated. (ERG, 2024)

· Flammable/combustible material.；· May ignite on contact with moist air or moisture.；· May burn rapidly with flare-burning effect.；· Some react vigorously or explosively on contact with water.；· Some may decompose explosively when heated or involved in a fire.；· May re-ignite after fire is extinguished.；· Runoff may create fire or explosion hazard.；· Containers may explode when heated.

· Flammable/combustible material.；· May ignite on contact with moist air or moisture.；· May burn rapidly with flare-burning effect.；· Some react vigorously or explosively on contact with water.；· Some may decompose explosively when heated or involved in a fire.；· May re-ignite after fire is extinguished.；· Runoff may create fire or explosion hazard.；· Containers may explode when heated.

Combustible. Gives off irritating or toxic fumes (or gases) in a fire.

Combustible solid. Easily oxidized. Heats spontaneously in contact with moisture and air, and may ignite surrounding combustible materials. Closed containers may rupture violently when heated.

Flammable when exposed to heat or flame. Ignites on contact with water or sodium chorite.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:；Fire will produce irritating, corrosive and/or toxic gases. Inhalation of decomposition products may cause severe injury or death. Contact with substance may cause severe burns to skin and eyes. Runoff from fire control or dilution water may cause environmental contamination. CAUTION: Pentaborane (UN1380) is highly toxic and may be fatal if inhaled, ingested or absorbed through skin. (ERG, 2024)

· Fire will produce irritating, corrosive and/or toxic gases.；· Inhalation of decomposition products may cause severe injury or death.；· Contact with substance may cause severe burns to skin and eyes.；· Runoff from fire control or dilution water may cause environmental contamination.；CAUTION: Pentaborane (UN1380) is highly toxic and may be fatal if inhaled, ingested or absorbed through skin.

· Fire will produce irritating, corrosive and/or toxic gases.；· Inhalation of decomposition products may cause severe injury or death.；· Contact with substance may cause severe burns to skin and eyes.；· Runoff from fire control or dilution water may cause environmental contamination.；CAUTION: Pentaborane (UN1380) is highly toxic and may be fatal if inhaled, ingested or absorbed through skin.

1384 135

1384 135

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:；DO NOT USE WATER, CO2 OR FOAM ON MATERIAL ITSELF. Some of these materials may react violently with water. CAUTION: For Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite) UN1384, UN1923 and UN1929, USE FLOODING AMOUNTS OF WATER for SMALL AND LARGE fires to stop the reaction. Smothering will not work for these materials, they do not need air to burn.；SMALL FIRE: Dry chemical, soda ash, lime or DRY sand, EXCEPT for UN1384, UN1923, UN1929 and UN3342.；LARGE FIRE: DRY sand, dry chemical, soda ash or lime EXCEPT for UN1384, UN1923, UN1929 and UN3342, or withdraw from area and let fire burn. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. If it can be done safely, move undamaged containers away from the area around the fire.；FIRE INVOLVING TANKS, RAIL TANK CARS OR HIGHWAY TANKS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Do not get water inside containers or in contact with substance. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks in direct contact with flames. (ERG, 2024)

Use carbon dioxide, dry sand, special powder, water in large amounts.

Fresh air, rest. Seek medical attention if you feel unwell.

Remove contaminated clothes. Rinse and then wash skin with water and soap.

Rinse with plenty of water (remove contact lenses if easily possible). Refer for medical attention.

Rinse mouth. Do NOT induce vomiting. Give one or two glasses of water to drink.

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.；· Stay upwind, uphill and/or upstream.；· Keep unauthorized personnel away.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.；· Do not touch or walk through spilled material.；· Stop leak if you can do it without risk.；Small Spill；CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal.；CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.；· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.；· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.；· Prevent entry into waterways, sewers, basements or confined areas.

· CALL 911. Then call emergency response telephone number on shipping paper. If shipping paper not available or no answer, refer to appropriate telephone number listed on the inside back cover.；· Stay upwind, uphill and/or upstream.；· Keep unauthorized personnel away.

· ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area.；· Do not touch or walk through spilled material.；· Stop leak if you can do it without risk.；Small Spill；CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal.；CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors.；· Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain.；· Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal.；· Prevent entry into waterways, sewers, basements or confined areas.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:；Refer to the "General First Aid" section. (ERG, 2024)

General First Aid:；· Call 911 or emergency medical service.；· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.；· Move victim to fresh air if it can be done safely.；· Administer oxygen if breathing is difficult.；· If victim is not breathing:；-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.；-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).；-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.；· Remove and isolate contaminated clothing and shoes.；· For minor skin contact, avoid spreading material on unaffected skin.；· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.；· For severe burns, immediate medical attention is required.；· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.；· Keep victim calm and warm.；· Keep victim under observation.；· For further assistance, contact your local Poison Control Center.；· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.；In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

General First Aid:；· Call 911 or emergency medical service.；· Ensure that medical personnel are aware of the material(s) involved, take precautions to protect themselves and avoid contamination.；· Move victim to fresh air if it can be done safely.；· Administer oxygen if breathing is difficult.；· If victim is not breathing:；-- DO NOT perform mouth-to-mouth resuscitation; the victim may have ingested or inhaled the substance.；-- If equipped and pulse detected, wash face and mouth, then give artificial respiration using a proper respiratory medical device (bag-valve mask, pocket mask equipped with a one-way valve or other device).；-- If no pulse detected or no respiratory medical device available, provide continuous compressions. Conduct a pulse check every two minutes or monitor for any signs of spontaneous respirations.；· Remove and isolate contaminated clothing and shoes.；· For minor skin contact, avoid spreading material on unaffected skin.；· In case of contact with substance, remove immediately by flushing skin or eyes with running water for at least 20 minutes.；· For severe burns, immediate medical attention is required.；· Effects of exposure (inhalation, ingestion, or skin contact) to substance may be delayed.；· Keep victim calm and warm.；· Keep victim under observation.；· For further assistance, contact your local Poison Control Center.；· Note: Basic Life Support (BLS) and Advanced Life Support (ALS) should be done by trained professionals.；In Canada, an Emergency Response Assistance Plan (ERAP) may be required for this product. Please consult the shipping paper and/or the "ERAP" section.

· Wear positive pressure self-contained breathing apparatus (SCBA).；· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.；· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

· Wear positive pressure self-contained breathing apparatus (SCBA).；· Wear chemical protective clothing that is specifically recommended by the manufacturer when there is NO RISK OF FIRE.；· Structural firefighters' protective clothing provides thermal protection but only limited chemical protection.

TIH (Toxic Inhalation Hazard) - Term used to describe gases and volatile liquids that are toxic when inhaled. Some are TIH materials themselves, e.g., chlorine, and some release TIH gases when spilled in water, e.g., chlorosilanes. [ERG 2016].

Special protective equipment for fire-fighters: Wear self contained breathing apparatus for fire fighting if necessary.

Use only flooding quantities of water. Monitor temperature of containers exposed to fire for at least 48 hours to verify decomposition has not begun in the sealed container.

Store in cool place. Keep container tightly closed in a dry and well-ventilated place. Do not store near acids. Air sensitive. Heat sensitive. Moisture sensitive. Handle under inert gas. Protect from moisture.

Store in a cool, dry, well-ventilated location. Outside or detached storage is preferred. Separate from combustibles and oxiding materials. Immediately remove and properly dispose of any spilled material.

Materials to avoid: strong oxidizing agents, acids.

Keep water away from release. Prompt cleanup and removal are necessary. Control runoff and isolate discharged material for proper disposal.

Personal precautions: Wear respiratory protection. Avoid dust formation. Avoid breathing dust. Ensure adequate ventilation.

Methods for cleaning up: Pick up and arrange disposal without creating dust. Keep in suitable, closed containers for disposal.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Excerpt from ERG Guide 135 [Substances - Spontaneously Combustible]:；ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. Do not touch or walk through spilled material. Stop leak if you can do it without risk.；SMALL SPILL: CAUTION: For spills of Xanthates, UN3342 and for Dithionite (Hydrosulfite/Hydrosulphite), UN1384, UN1923 and UN1929, dissolve in 5 parts water and collect for proper disposal. CAUTION: UN3342 when flooded with water will continue to evolve flammable Carbon disulfide/Carbon disulphide vapors. Cover with DRY earth, DRY sand or other non-combustible material followed with plastic sheet to minimize spreading or contact with rain. Use clean, non-sparking tools to collect material and place it into loosely covered plastic containers for later disposal. Prevent entry into waterways, sewers, basements or confined areas. (ERG, 2024)

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. Observe all federal, state, and local environmental regulations. Contact a licensed professional waste disposal service to dispose of this material.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Do NOT let this chemical enter the environment. Sweep spilled substance into covered containers. Carefully collect remainder. Then store and dispose of according to local regulations. Do NOT absorb in saw-dust or other combustible absorbents.

Sodium hyposulfite at a concentration of 1 x 10-5 M decreased the number of chromosome fragments produced by cobalt 60 gamma rays in Tradescantia paludosa (clone B2-2) root tip by 46%. Concentrations of 1 x 10-4 or 1 x 10-3 M were no more effective, and the 1 x 10-3 M concentration was toxic to the root tips.

LC50 Species; Leuciscus idus (ide, freshwater fish); Conditions: German Industrial Standard DIN 38 412, Part 15; Concentration: 63.2 mg/L (nominal) for 96 hr

EC50; Species: Daphnia magna (water flea); Conditions: Directive 79.831 EEC, C2; Concentration: 98.3 mg/L for 48 hr, endpoint: immobilization /Effect not given in source/

Human Health: Sodium dithionite is not stable under physiological conditions, with the rate of decomposition increasing with increasing acidity. Upon contact with moisture, it is oxidized to hydrogen sulfite, sulfite and hydrogen sulfate, and under strongly acidic conditions it may liberate sulfur dioxide. Under anaerobic conditions (such as in the lower gastrointestinal tract), hydrogen sulfite and thiosulfate may be formed. Hydrogen sulfite can be absorbed after ingestion. It is efficiently metabolized, and the major part rapidly excreted as sulfate into the urine. The acute oral LD50 of sodium dithionite in rats was about 2500 mg/kg bw, with atony, gastro-intestinal irritation, diarrhea and dyspnea as the main clinical and pathological signs at doses near to or exceeding the LD50. There were no acute dermal and no valid acute inhalation studies available. Sodium dithionite was slightly irritating to the skin, and strongly irritating to the eyes of rabbits. Under acidic conditions, sodium dithionite may liberate sulfur dioxide, which is known to induce respiratory irritation in humans. There was no animal data available regarding sensitization. In humans, allergic dermatitis from exposure to sulfites is rare and, consequently, sodium dithionite is not considered to possess a significant skin sensitization potential. Although there were no specific reports with regard to sodium dithionite available, the potential for allergoid reactions ("sulfite-asthma") should be assumed in sensitive individuals following oral or inhalation exposure. Sodium dithionite was not tested for its toxicity after repeated dosing. Due to its rapid degradation under in vivo conditions, the toxicity data on its decomposition products were used for the evaluation of this endpoint. The conversion products, including sulfite, hydrogen sulfite, sulfate and thiosulfate, are considered as substances of very low order systemic toxicity. It should be noted that sulfites, in general, reduce the thia

/AQUATIC SPECIES/ A test following Directive 79/831/EEC, C2, with Daphnia magna with 10 nominal concentrations, plus a control ranging from 0.976 - 500 mg/L, resulted in an EC50 (48 hr, immobilization) of 98.3 mg/L. As oxygen values in the 250 mg/L and 500 mg/L test solutions were below 1 mg/L at the beginning of the test, it cannot be excluded that the toxicity was in part due to oxygen deficiency effects.

/AQUATIC SPECIES/ In a study with Leuciscus idus, following the German Industrial Standard DIN 38 412, Part 15, six concentrations from 21.5 - 147 mg/L (nominal), plus a control and pH adjusted 147 mg/L and 500 mg/L group, were tested. An LC50 (96 hr) of 63.2 mg/L (nominal) was calculated. All fish in the pH adjusted 147 mg/L and 500 mg/L concentration groups died within one hour. Less than 1 mg/L oxygen was measured in those test solutions at test start. In a pre-test in which the fish were placed into the aquaria 1 hr after preparation of the test solution the initial oxygen consumption was compensated by the continuous aeration and the concentration of 100 mg/L did not cause any mortality or symptoms. Therefore, the toxic effect may be, in part, due to oxygen deficiency.

/AQUATIC SPECIES/ Acute toxicity to Scenedesmus subspicatus was determined in a study, following the German Industrial Standard DIN 38 412 Part 9, with 7 nominal concentrations ranging from 7.81 -500 mg/L, plus a control. The ErC50 (72 hr) for growth rate was 206 mg/L (nominal concentration) and the NOEC 62.5 mg/L (nominal concentration); corresponding values for the endpoint biomass were 135 mg/L and 62.5 mg/L respectively.

/AQUATIC SPECIES/ The following chronic toxicity test with aquatic organisms is available: Water flea (Daphnia magna): NOEC (21 d) > 10 mg/L. Three concentrations (1, 5, and 10 mg/L) were tested.

Cough. Sore throat.

Redness. Pain.

Nausea. Abdominal pain. Vomiting. Diarrhoea.

/SIGNS AND SYMPTOMS/ Probable oral lethal dose (human) 0.5-5 g/kg bw. Because of rapid oxidation to sulfates, sulfites are well tolerated until large dises are reached; then violent colic and diarrhea, circulatory disturbances, central nervous depression, and death are described.

/SIGNS AND SYMPTOMS/ May cause respiratory tract irritation ... May cause skin irritation. May cause eye irritation.

/CASE REPORTS/ ... A female dry cleaner is reported to have developed hand dermatitis presumably due to regular preparation of sodium sulfite solutions. Patch testing gave a positive response on application of a 0.5% and 1% solution of sodium dithionite.

/ALTERNATIVE and IN VITRO TESTS/ Incubation of normal human erythrocytes with sodium dithionite resulted in the formation of Heinz bodies. Addition of superoxide dismutase to the incubation medium incr the formation of Heinz bodies by sodium dithionite.

/OTHER TOXICITY INFORMATION/ Under acidic conditions, sodium dithionite may liberate sulfur dioxide (SO2). Sulfur dioxide is known to induce respiratory irritation and in disposed humans also bronchospasms. The hypersensitivity reaction is also known as "sulfite-asthma" and linked to SO2 exposure or the use of SO2 or bisulfite as antioxidants in foodstuffs. About 10 % of asthmatic humans are reportedly sulfite- or SO2-sensitive.

/LABORATORY ANIMALS: Acute Exposure/ 2% aq soln of sodium hydrosulfite adjusted to pH 7 with sodium bicarbonate tested on rabbit eyes by irrigation of surface of eye for 10 min after removal of corneal epithelium caused slight corneal edema ...

/LABORATORY ANIMALS: Acute Exposure/ For sodium dithionite (tested as suspension in aqueous carboxymethylcellulose), an oral LD50 of about 2500 mg/kg bw was determined for rats. No clinical signs were noted at doses up to and including 1600 mg/kg bw. At higher doses (>= 2000 mg/kg bw), clinical signs included atony, dyspnea and diarrhea. Gross pathology revealed acute hyperemic congestion, cardiac dilatation, gastrointestinal irritation and dilatation, associated with bloody ulceration in animals administered doses of 2500 mg/kg bw or higher.

/LABORATORY ANIMALS: Acute Exposure/ An 80% aqueous suspension of sodium dithionite tested in two rabbits under occlusive conditions for 20 hours produced mild skin erythema. The mild erythema seen at 24 hours post-treatment did not persist to 8 days. With an exposure time of 20 hours (instead of 4 hours), and occlusive conditions (instead of semi-occlusive), the test conditions were more stringent than those required in the current OECD TG 404.

/LABORATORY ANIMALS: Acute Exposure/ Sodium dithionite was tested for its effects on the eye of rabbits in a study performed in accordance with OECD TG 405. 97 mg of the finely powdered test substance (purity 88%) were instilled in the conjunctival sac of three rabbits, and washed out with physiological saline after one hour of exposure. In all animals, moderate to severe erythema and slight edema were found after 1 hour and persisted until 72 and 48 hours, respectively. Mean scores for erythema were 3.0 (24 hr), 3.0 (48 hr), and 2.3 (72 hr), and for edema 1.3 (24 hr), 0.67 (48 hr), and 0.33 (72 hr). No changes were noted in the cornea and iris. All effects were completely reversible by day 7 after exposure except for 1 animal which still showed slight conjunctival redness.

For more Non-Human Toxicity Excerpts (Complete) data for Sodium hydrosulfite (9 total), please visit the HSDB record page.

Chemical: Dithionous acid, disodium salt

Dithionous acid, sodium salt (1:2) is listed on the EPA's Chemical Data Reporting (CDR) system. Manufacturers and importers of Dithionous acid, sodium salt (1:2) are required to report information about their production and use of this chemical to the EPA under the Toxic Substances Control Act (TSCA). (40 eCFR Part 711)

Status: Active Update: 01-02-2023 https://echa.europa.eu/registration-dossier/-/registered-dossier/15288

Dithionous acid, disodium salt: Does not have an individual approval but may be used under an appropriate group standard

The New Jersey Worker and Community Right to Know Act requires public and private employers to provide information about hazardous substances at their workplaces. (N.J.S.A. 34:5A-1 et. seq.)

Sodium hydrosulfite

A Commercial Grade

A Placarded Amount

Chemical or material that can be mixed with readily available materials.

Sodium dithionite is not stable under physiological conditions, with the rate of decomposition increasing with increasing acidity. Upon contact with moisture, it is oxidized to hydrogen sulfite, sulfite and hydrogen sulfate, and under strongly acidic conditions it may liberate sulfur dioxide. Under anaerobic conditions (such as in the lower gastrointestinal tract), hydrogen sulfite and thiosulfate may be formed. Hydrogen sulfite can be absorbed after ingestion. It is efficiently metabolized, and the major part rapidly excreted as sulfate into the urine.

As sodium dithionite is chemically unstable in the presence of water and oxygen, in particular under acidic conditions, rapid conversion of sodium dithionite into various related sulfite species is expected to occur under physiological conditions. Therefore, it is justified to take account of toxicological data of sodium sulfite, sodium hydrogen sulfite, and disodium disulfite (= sodium metabisulfite) in the human health assessment of dithionite ... In this context, sodium sulfite and sodium hydrogen sulfite are considered to be the predominant chemicals that are systemically available to the body.

Used to dye fibers and textiles, to strip dyes from fabrics, and to bleach sugar, soap, oils and wood pulp; Used as a chemical reagent and an oxygen scavenger in the production of synthetic rubber; [Hawley]

Pulp and Paper Processing [Category: Industry]；Textiles (Printing, Dyeing, or Finishing) [Category: Industry]；Toxic Gas from Spilling Chemical in Water [Category: Other]

Reducing agent to strip certain dyes from fabrics and in vat dyeing; bleaching agent for ground wood pulp, soap, straws, sugar reducing agent to strip certain dyes from fabrics and in vat dyeing; bleaching agent for ground wood pulp, soap, straws, sugar

Oxygen scavenger for synthetic rubbers; vat dyeing of fibers and textiles; stripping agent for dyes; reagent; bleaching of sugar, soap, oils, and groundwood.

As reducing agent, particularly in dyeing with indigo and vat dyes; bleaching soaps, straw; removing dyes from dyed fabrics.

All uses of sodium dithionite are based on its reducing properties. In the textile industry, sodium dithionite is primarily used as reducing agent for vat dyes and sulfur containing dyes, and for the removal of pigments on textiles. It is also used as a bleaching agent in reductive bleaching processes, for instance, in the bleaching of mechanical paper pulp, and the bleaching of cotton and wool, as well as sugar.

(1972) 1.63X10+9 grams

(1975) 3.9X10+9 grams

CHEMICAL PROFILE: Sodium Hydrosulfite. US Exports: 2001: 8,000 short tons; 2002: 9,000 short tons.

CHEMICAL PROFILE: Sodium Hydrosulfite. US Exports: 2004: 8,300 short tons; 2005: 7,900 short tons.

(1972) 6.35X10+8 grams

(1975) 9.08X10+7 grams

CHEMICAL PROFILE: Sodium Hydrosulfite. US Imports: 2001: 18,000 short tons; 2002: 17,000 short tons.

CHEMICAL PROFILE: Sodium Hydrosulfite. US Imports: 2004: 35,300 short tons; 2005: 33,500 short tons.

2023: 100,000,000 - <500,000,000 lb；2022: 100,000,000 - <500,000,000 lb；2021: 100,000,000 - <500,000,000 lb；2020: 100,000,000 - <500,000,000 lb

(1972) 4.26X10+10 grams

(1975) 4.54X10+10 grams

Production volumes for non-confidential chemicals reported under the Inventory Update Rule. [Table#2081]

Production volume for non-confidential chemicals reported under the 2006 Inventory Update Rule. Chemical: Dithionous acid, sodium salt (1:2). Aggreated National Production Volume: 100 to <500 million lbs.

For more U.S. Production (Complete) data for Sodium hydrosulfite (13 total), please visit the HSDB record page.

70% as a reducing agent in vat dyeing; 15% as a bleaching agent for pulp; 15% in misc bleaching, reducing, and dyestripping applications (1972)

CHEMICAL PROFILE: Sodium Hydrosulfite. End-use pattern for sodium hydrosulfite in 1985.；Table: End-use pattern for sodium hydrosulfite in 1985. [Table#2071]

CHEMICAL PROFILE: Sodium Hydrosulfite. End-use pattern for sodium hydrosulfite in 1988.；Table: End-use pattern for sodium hydrosulfite in 1988. [Table#2072]

CHEMICAL PROFILE: Sodium Hydrosulfite. End-use pattern for sodium hydrosulfite in 1991.；Table: End-use pattern for sodium hydrosulfite in 1991. [Table#2073]

For more Consumption Patterns (Complete) data for Sodium hydrosulfite (17 total), please visit the HSDB record page.

Zinc dust process: ... An aqueous slurry of zinc dust is treated in a stirred reactor with cooling at ca. 40 °C with liquid or gaseous sulfur dioxide to give zinc dithionite. After completion of the reaction the solution is passed through a filter press to remove unreacted zinc dust and impurities from the zinc. The zinc is then precipitated from the zinc dithionite by adding sodium carbonate or sodium hydroxide in stirred vessels. The zinc carbonate or hydroxide is removed in filter presses. Anhydrous sodium dithionite is precipitated from the clarified sodium dithionite solution by concentration under vacuum and addition of sodium chloride at > 60 °C. It is filtered, washed with methanol, and dried at 90 - 100 °C. Besides the evaporation process the salting out process, which was more widely used previously, is still known. In this process the dithionite is obtained from the solution by the addition of sodium chloride and methanol.

Amalgam Process. In the amalgam process, sodium hydrogensulfite is reduced to sodium dithionite in aqueous solution in a cooled, stirred vessel using the sodium amalgam of a chloralkali electrolysis cell. The sodium-free mercury is returned to the electrolysis cell where it is recharged with sodium. During reaction of the amalgam with the hydrogensulfite solution a pH of 5 - 6 must be maintained. The product is obtained by precipitation with salts or methanol or both.

Formate Process: Sodium formate, dissolved in 80% aqueous methanol, is charged to a stirred vessel. At a pressure of 2 - 3 bar sulfur dioxide and sodium hydroxide are introduced into this solution such that a pH of 4 - 5 is maintained.

Sodium Borohydride Process Sodium borohydride is stable in strong aqueous alkali and can be used in this form for the production of sodium dithionite by adding SO2 and sodium hydroxide.

For more Methods of Manufacturing (Complete) data for Sodium hydrosulfite (8 total), please visit the HSDB record page.

Commercial sodium dithionite generally has a purity of about 88%. It contains about 3% of each of the following: sodium disulfite, sodium sulfite, sodium sulfate, and sodium carbonate. The latter stabilizes the Na2S2O4. The total heavy metal content is generally < 20 ppm. The product from the zinc-dust process has a zinc content of up to 300 ppm.

Grades: technical; reagent. /Dihydrate/

Blankit

Burmol

For more Formulations/Preparations (Complete) data for Sodium hydrosulfite (17 total), please visit the HSDB record page.