95% Sodium allylsulfonate CAS:2495-39-8

What is Sodium Allyl Sulfonate?

Sodium allyl sulfonate (also known as sodium propylene sulfonate, 2-propylene-1-sulfonate, or Sodium 2-propene-1-sulfonate, abbreviated as SAS or ALS) is a sulfonate functional monomer with an allyl double bond. It is an important fine chemical in the electroplating and polymer industries. Its chemical formula is usually written as:

C3H5NaO3S (CH2=CH-CH2-SO3Na, CAS No.: 2495-39-8, EINECS No.: 219-676-5, molecular weight approximately 144.13)

It is a white crystalline powder at room temperature, and commercially available products are often supplied as a clear aqueous solution of about 35% (containing a small amount of sodium chloride byproduct). It is readily soluble in water but insoluble in most organic solvents such as benzene, and has a density of about 1.206 g/cm³. Sodium allyl sulfonate is usually prepared by reacting allyl chloride (3-chloropropene) with sodium sulfite .

From a molecular structure perspective, sodium allyl sulfonate has a carbon-carbon double bond (CH2=CH-) at one end and a strongly hydrophilic sulfonic acid group (-SO3Na) at the other end. This dual-functional structure of “polymerizable at one end and strongly hydrophilic at the other” allows it to participate in copolymerization as a monomer and also endows the polymer with excellent hydrophilic, dispersing and scale-inhibiting properties—which is the structural basis for its use as an electroplating brightener and a water-soluble functional monomer.

Chemically, sodium allyl sulfonate can undergo free radical polymerization, copolymerizing with monomers such as acrylic acid, acrylamide, and methacrylic acid to form water-soluble polymers. It exhibits good thermal stability, its aqueous solution is weakly alkaline, and it is mild in nature, but may cause slight irritation to the skin and eyes. It should be stored in a sealed, moisture-proof container and protected from strong oxidizing agents.

Industrial-grade sodium allyl sulfonate refers to products intended for industrial applications such as electroplating, chemical fibers, water treatment, and building materials. Compared to reagent-grade products, industrial-grade products place greater emphasis on the following indicators:

Unsaturation (allyl activity)

The content of double bonds reflects the polymerization activity of monomers and is a core quality indicator for electroplating and copolymerization applications.

Sodium chloride content

The solution-type product contains approximately 8% sodium chloride byproduct. The sodium chloride content affects the product purity and downstream applications, and must be controlled.

Color and turbidity

The solution should be colorless to slightly yellow and clear. Abnormal color and turbidity often indicate oxidation or process impurities.

What are the uses of industrial-grade Sodium Allyl Sulfonate?

Industrial-grade sodium allyl sulfonate, with its bifunctional structure of “polymerizable double bonds + strong hydrophilic sulfonic acid groups”, has wide applications in electroplating, chemical fiber, water treatment and building materials:

1.Nickel plating brightener (core application)

Sodium allyl sulfonate is an important auxiliary brightener in nickel plating (generally used at a dosage of 0.1-0.2 g/L). It can improve the dispersion and coverage of the plating solution, improve the brightness, uniformity and ductility of the nickel plating layer, and make the plating layer denser and brighter. It is widely used in hardware, sanitary ware, automotive and electronic electroplating.

2.Third monomer of acrylic fiber

Sodium allyl sulfonate is used as the third monomer for acrylic fiber (polyacrylonitrile fiber) to improve the dyeing performance of the fiber, making the fiber absorb color quickly, have high fastness and bright color, and improve heat resistance and elasticity. It is an important modifying monomer in the chemical fiber industry.

3.Monomers for water treatment scale inhibitors and dispersants

Sodium allyl sulfonate is copolymerized with acrylic acid, acrylamide, etc. to form a water-soluble scale inhibitor and dispersant, which is used for scale inhibition and prevention in circulating cooling water, boiler water and reverse osmosis systems, helping to prevent the deposition of scale such as calcium carbonate and calcium sulfate.

4.Polycarboxylate superplasticizer copolymer monomer (concrete admixture)

Sodium allyl sulfonate is used as a comonomer of polycarboxylate superplasticizers, giving the superplasticizers good dispersibility and slump retention properties. It is used in the production of high-performance concrete and is a core admixture raw material for modern construction and infrastructure.

5.Oilfield chemicals

Sodium allyl sulfonate is copolymerized with acrylamide and other substances to produce oilfield treatment agents, which are used as filtration reducers and oil production aids in drilling fluids to help improve drilling fluid performance and oil and gas extraction efficiency, serving the oil and gas industry.

6.Synthesis of water-soluble polymers

Sodium allyl sulfonate is a functional monomer for synthesizing water-soluble polymers. It is used to prepare functional polymers such as dispersants, thickeners, and detergent additives, serving industries such as papermaking, textiles, daily chemicals, and industrial cleaning.

7.Other Applications

With the development of functional polymers and green chemical technologies, the application scope of industrial-grade sodium allyl sulfonate continues to expand, including in areas such as fine chemical intermediates and functional coating additives.

It should be noted that industrial grade does not mean “risk-free”: Although sodium allyl sulfonate is mild in nature, its dust and solution can cause slight irritation to the skin and eyes. Protective equipment should be worn and the operation should be carried out in a well-ventilated area. The solution product is weakly alkaline and should not be stored with strong acids or strong oxidants. It must be stored in a sealed and moisture-proof container.

Summarize

Sodium allyl sulfonate (SAS, CAS No. 2495-39-8) is a white crystalline powder or supplied as a 35% aqueous solution. It is a sulfonate functional monomer with a carbon-carbon double bond at one end and a strongly hydrophilic sulfonic acid group at the other, possessing both polymerization activity and hydrophilic dispersing properties. In daily life, we indirectly encounter it through electroplating hardware and bathroom products, acrylic clothing, tap water and industrial water treatment, construction engineering, oil and gas, and testing laboratories. In industry, sodium allyl sulfonate with a content of over 95% is widely used in nickel plating brighteners, as a third monomer for acrylic fibers, as a scale inhibitor and dispersant in water treatment, as a comonomer for polycarboxylate superplasticizers, in oilfield chemicals, and in the synthesis of water-soluble polymers. It is an important fine chemical connecting “functional monomers” with “electroplating, chemical fibers, water treatment, building materials, and energy.”