SODIUM SULFITE

Sodium sulfite is used in a variety of industries, including photography, cosmetics, and wastewater treatment, serving as a reducing agent, hair straightening agent, and preservative.
Sodium sulfite is produced by reacting ammonia with sulfur dioxide in aqueous solution, and can be oxidized to form ammonium sulfate, which is used as a fertilizer.
Sodium sulfite is registered under the REACH Regulation and is manufactured or imported in the European Economic Area at quantities ranging from 100 to 1,000 tonnes per annum, with environmental precautions necessary due to its potential impact.

CAS Number: 10196-04-0
EC Number: 233-484-9
Molecular Formula: H8N2O3S
Molecular Weight: 116.14

Synonyms: Ammonium sulfite, Ammonium sulphite, 10196-04-0, DiAmmonium sulfite, diazanium;sulfite, 8LF589Y5GD, Sulfurous acid, diammonium salt, Diammonium sulfonate, ammoniumsulfite, Ammoniumsulfit, diazanium;sulite, Ammonium sulfonate, UNII-8LF589Y5GD, Sulfurous acid, ammonium salt, Ammonium sulfite [MI], Ammonium sulfite [HSDB], DTXSID2064991, HSDB 1426, CHEBI:186946, EINECS 233-484-9, Sulfurous acid ammonium salt (1:2), AKOS015904487, Sulfurous acid, ammonium salt (1:2), NS00080977, EC 233-484-9

Sodium sulfite is the ammonium salt of sulfurous acid with the chemical formula (NH4)2SO3.

Sodium sulfite is a colorless crystalline solid.
The primary hazard is the threat to the environment.

Immediate steps should be taken to limit its spread to the environment.
Sodium sulfite is used in the manufacture of other chemicals, in medicine, and photography.

Sodium sulfite has a wide use of applications, such as hair straightening or waving agents, as an ingredient in carmel food coloring, as well as an reducing agent in photography.
Other applications that Sodium sulfite is used in include lubricants for cold metal working and blast furnace linings.

Sodium sulfite is an ammonium salt of sulfurous acid and a byproduct of the flue gas desulfuration process by ammonia.
Sodium sulfite can be oxidized into ammonium sulfate, which can be used as a fertilizer.

Sodium sulfite is registered under the REACH Regulation and is manufactured in and / or imported to the European Economic Area, at ≥ 100 to < 1 000 tonnes per annum.
Sodium sulfite is used by consumers, by professional workers (widespread uses), in formulation or re-packing, at industrial sites and in manufacturing.

Sodium sulfite is a chemical compound that is used as an additive in wastewater treatment and as a reagent in organic synthesis.
The reaction solution contains Sodium sulfite, sodium carbonate, and water.

Sodium sulfite has been shown to be toxic to animals when administered at high doses.
Sodium sulfite does not react with hydrogen fluoride or water and it is not soluble in anhydrous sodium.

The polymerase chain reaction (PCR) technique has been used to study the reaction mechanism of Sodium sulfite.
The reactions are catalysed by metal hydroxides such as magnesium hydroxide and aluminium hydroxide, which are present at the surface of the solid phase.

Sodium sulfites are compounds that contain the sulfite ion.
The sulfite ion is the conjugate base of bisulfite.

Although Sodium sulfite is elusive, its salts are widely used.
Sodium sulfite is used in the photography industry to protect developing solutions from oxidation, in the pulp and paper industry, in water treatment as an oxygen scavenger agent, as a desulfurizing and dechlorinating agent in the leather industry and as a bleaching agent in textile industry.

Sodium sulfite is a component in many pharmaceuticals, which is effective to maintain the potency and stability of drugs.
Sodium sulfite is added to a number of drug preparations as an antioxidant and antimicrobial agent.

Sodium sulfite is used as a food preservative.
Topical, oral or parenteral exposure to sulphites has been reported to induce a range of adverse clinical effects in sensitive individuals, ranging from dermatitis, urticaria, flushing, hypotension, abdominal pain and diarrhoea to life-threatening anaphylactic and asthmatic reactions.

Exposure to the sulphites arises mainly from the consumption of foods and drinks that contain these additives; however, exposure may also occur through the use of pharmaceutical products, as well as in occupational settings.
Sodium sulfite is accepted for use as a food additive in Europe.

Sodium sulfite is generally recognized as safe by FDA.
Sodium sulfite is included in FDA Inactive Ingredients Database (epidural, IM, IV, and SC injections; inhalation solution; ophthalmic solutions; oral syrups and suspensions; otic solutions; topical creams and emulsions).
Included in nonparenteral medicines licensed in the UK.

Sodium sulfite has been shown to be toxic to animals when administered at high doses.
Sodium sulfite does not react with hydrogen fluoride or water and Sodium sulfite is not soluble in anhydrous sodium.

Uses of Sodium sulfite:
Sodium sulfite is an additive used in the production of caramel.

Sodium sulfite is used in photography and in the production of caramel, refractory bricks, lubricants, medicines, permanent wave solutions, ammonium thiosulfite, and ammonium chloride
Sodium sulfite is used in photography; as reducing agent; in bricks for blast furnace linings; in lubricants for metal cold-working.

Sodium sulfite is used in production of ammonium thiosulfite.
Sodium sulfite is the precursor to ammonium thiosulfate, by reaction with elemental sulfur.

Niche:
For cosmetics, Sodium sulfite is used as a hair straightening agent and a hair waving agent.
Ammonium based hair products have been made to replace sodium hydroxide-based products due to the destructive nature of sodium hydroxide on hair.

The most common food product with Sodium sulfite is caramel coloring E150d.
According to the FDA, caramel coloring contains ammonium or potassium.

Sodium sulfite is used as a preservative for fixers in photography.
When film photographs are being developed Sodium sulfite can be one of the reducing agents used to preserve the hypo (sodium thiosulfate or ammonium thiosulfate).

Sodium sulfite can also be used in the making of bricks.
The bricks made using Sodium sulfite are mainly used for blast furnace linings.

Sodium sulfite can be included in lubricants for cold metal working.
The lubricants are intended to reduce friction to keep heat production down and keep impurities out of the metals.

Widespread uses by professional workers:
Sodium sulfite is used in the following products: adsorbents, metals, coating products, fertilisers, metal surface treatment products, non-metal-surface treatment products, hydraulic fluids, inks and toners, pH regulators and water treatment products, leather treatment products, lubricants and greases, metal working fluids, paper chemicals and dyes, photo-chemicals, polishes and waxes, textile treatment products and dyes, washing & cleaning products, water treatment chemicals and welding & soldering products.
Sodium sulfite is used in the following areas: mining, agriculture, forestry and fishing and printing and recorded media reproduction.
Sodium sulfite is used for the manufacture of: food products, textile, leather or fur, wood and wood products, metals and furniture.

Release to the environment of Sodium sulfite can occur from industrial use: formulation of mixtures, as processing aid, manufacturing of Sodium sulfite and in processing aids at industrial sites.
Other release to the environment of Sodium sulfite is likely to occur from: indoor use as reactive substance and outdoor use as reactive substance.

Industry Uses:
Oxidizing/reducing agents
Intermediate
Agricultural chemicals (non-pesticidal)
Processing aids, not otherwise listed
Soil amendments (fertilizers)

Uses at industrial sites:
Sodium sulfite is used in the following products: textile treatment products and dyes.
Sodium sulfite has an industrial use resulting in manufacture of another substance (use of intermediates).

Sodium sulfite is used in the following areas: mining and formulation of mixtures and/or re-packaging.
Sodium sulfite is used for the manufacture of: textile, leather or fur, pulp, paper and paper products and chemicals.

Release to the environment of Sodium sulfite can occur from industrial use: formulation of mixtures, as processing aid, manufacturing of Sodium sulfite, in processing aids at industrial sites, as an intermediate step in further manufacturing of another substance (use of intermediates), for thermoplastic manufacture and of substances in closed systems with minimal release.
Other release to the environment of Sodium sulfite is likely to occur from: indoor use as reactive substance and outdoor use as reactive substance.

Consumer Uses:
Processing aids, not otherwise listed
Soil amendments (fertilizers)
Oxidizing/reducing agents
Agricultural chemicals (non-pesticidal)

Background information on use in cosmetics:
Preservatives protect cosmetic products against microbial spoilage and hence make a major contribution to consumer health.
Preservatives are particularly required in cosmetic formulations containing water, because microorganisms can colonise and reproduce in an aqueous (water-containing) environment.

Cosmetics often contain more than one preservative substances and these preservative systems act simultaneously against different bacteria, yeasts or moulds.
Each of these substances has been comprehensively tested and assessed for safety (individually and in combination).
Manufacturers always use only the lowest possible effective concentration in a product so that an optimum shelf life and safe application are ensured.

Information on safe use:
Sodium sulfite is expressly approved and / or subject to a restriction as a result of an entry in Annex III of the EC Cosmetics Regulation after an assessment by the Scientific Committee on Consumer Safety of the EU Commission (SCCS).
Restrictions can relate eg to purity criteria, a maximum concentration or the restriction to certain product categories.
Subject to the conditions possibly imposed in Annex III, the use of Sodium sulfite in cosmetic products is safe.

In accordance with the EC Cosmetics Regulation (Regulation (EC) No. 1223/2009), which applies to the entire EU market, preservatives means substances which are exclusively or mainly intended to inhibit the development of microorganisms in the cosmetic product.
Annex V of the Regulation defines Sodium sulfites which may be used as preservatives in cosmetic products.
In this so-called positive list of preservatives, maximum concentrations are defined for the use of these substances in cosmetic products as well as the permissible uses.

Preservatives are examined in respect of their toxicological safety prior to their approval in Annex V and undergo extensive tests.
Manufacturers must prove the health safety in extensive scientific studies.

Experimental Properties of Sodium sulfite:

Chemical properties:
Sodium sulfite is a reducing agent.
Sodium sulfite emits sulfur dioxide and oxides of nitrogen upon heating to decomposition.

The specific gravity of Sodium sulfite is 1.41.
The refractive index of Sodium sulfite is 1.515.

Sodium sulfite is a colorless to yellow crystalline (sand-like or sugar-like) solid, normally sold or used in a 40% solution.
Sodium sulfite is used both as a reducing agent and in photography.

Sodium sulfite is a salt that can form from the reaction of ammonia and sulfur dioxide or hydrogen sulfide.
Sodium sulfite is frequently found in the overhead of crude distillation units and can be quite corrosive to steel equipment.
Chemical corrosion inhibitors are often used to control corrosion from Sodium sulfite and other ammonium salts.

Physical properties:
Sodium sulfite is colorless monoclinic crystals.
Sodium sulfite is soluble in water, its aqueous solution is alkaline.

Sodium sulfite is slightly soluble in alcohol.
Sodium sulfite is insoluble in acetone and carbon disulfide.

Sodium sulfite is easily oxidized to ammonium sulfate in air.
Sodium sulfite can be decomposed into ammonia and sulfur dioxide when heated.

Preparation of Sodium sulfite:

Sodium sulfite can be prepared by the reaction of ammonia with sulfur dioxide in aqueous solution:
2 NH3 + SO2 + H2O → (NH4)2SO3

Sodium sulfite is produced in gas scrubbers, now obsolete, consisting of ammonium hydroxide to remove sulfur dioxide from emissions from power plants.
The conversion is the basis of the Walther Process.
The resulting Sodium sulfite can be air oxidized to give ammonium sulfate.

Manufacturing Methods of Sodium sulfite:
In the ATS process, sulfur dioxide is absorbed from incinerated Claus tail gas in aqueous ammonia to produce Sodium sulfite and ammonium bisulfite in solution.

Identifiers of Sodium sulfite:
CAS Number: 10196-04-0
ChemSpider: 23404
ECHA InfoCard: 100.030.428
EC Number: 233-484-9
PubChem CID: 25041
UNII: 8LF589Y5GD
UN number: 3077
CompTox Dashboard (EPA): DTXSID2064991
InChI: InChI=1S/2H3N.H2O3S/c;;1-4(2)3/h2*1H3;(H2,1,2,3)
Key: PQUCIEFHOVEZAU-UHFFFAOYSA-N

SMILES:
[H][N+]([H])([H])[H].[H][N+]([H])([H])[H].O=S([O-])[O-]
[O-]S([O-])=O.[NH4+].[NH4+]

HS Code: 2832 20 00
Quality Level: MQ200

CAS Registry Number: 10196-04-0
Molecular Formula: H8N2O3S
Molecular Weight: 116.14
Percent Composition: H 6.94%, N 24.12%, O 41.33%, S 27.61%
Line Formula: (NH4)2SO3

Molecular weight: 116.14 g/mol
Formula: (NH4)2SO3
Purity: Min. 95%
Color/Form: Powder
MDL: MFCD00066094
HS code: 2832200000

Properties of Sodium sulfite:
Chemical formula: (NH4)2SO3
Molar mass: 116.14 g/mol
Appearance: colourless hygroscopic crystals
Melting point: 65 °C (149 °F; 338 K) decomposes
Solubility in water: 35 g/100 mL
32.4g/100mL at 0 degrees Celsius
60.4g/100mL at 100 degrees Celsius
Solubility: Insoluble in acetone and alcohol
Refractive index (nD): 1.515.

Density: 1.19 g/cm3 (20 °C)
Melting Point: 4 - 8 °C
pH value: 7.5 - 7.6 (H₂O, 20 °C)

Molecular Weight: 116.14 g/mol
Hydrogen Bond Donor Count: 2
Hydrogen Bond Acceptor Count: 4
Rotatable Bond Count: 0
Exact Mass: 116.02556330 g/mol
Monoisotopic Mass: 116.02556330 g/mol
Topological Polar Surface Area: 84.4Å²
Heavy Atom Count: 6
Complexity: 18.8
Isotope Atom Count: 0
Defined Atom Stereocenter Count: 0
Undefined Atom Stereocenter Count: 0
Defined Bond Stereocenter Count: 0
Undefined Bond Stereocenter Count: 0
Covalently-Bonded Unit Count: 3
Compound Is Canonicalized: Yes

Specifications of Sodium sulfite:
Assay (iodometric): 37.0 - 40.0 %
Density (d 20 °C/ 4 °C): 1.195 - 1.205

density: 1.19 g/cm3 at 20 °C
form: liquid
mp: 4-8 °C
pH: 7.5-7.6 (20 °C in H2O)
Quality Level: 200
storage temp.: 2-30°C

Names of Sodium sulfite:

IUPAC name:
Sodium sulfite
Sodium sulfite Monohydrate
ammonium sulphite
diSodium sulfite
diazanium sulfite
Sulfurous acid, diammonium salt

Regulatory process names:
Sodium sulfite
Ammonium sulphite
ammonium sulphite
Sulfurous acid, diammonium salt

Other names:
Ammonium sulphite
DiSodium sulfite
Diammonium sulfonate
Sulfurous acid
Diammonium salt
Sulfurous acid
ammonium salt(1:2)

Other identifiers:
10196-04-0