Sodium dodecyl sulfate

Product Details

CasNo： 151-21-3

MF： C12H25NaO4S

Appearance： powder

Delivery Time： 15 days

Packing： 25kg/bag

Purity： 99%

1. Basic Information​

1.1 Chemical Formula​

The chemical formula of sodium dodecyl sulfate is ​

C12​H25​SO4​Na

. Its molecular structure consists of a long - chain alkyl group (​

C12​H25​−

) and a sulfate group (​

−SO4​Na

). The long - chain alkyl group provides hydrophobicity, while the sulfate group endows it with hydrophilicity, which is the key to its surfactant properties.​

1.2 CAS Number​

The CAS number of sodium dodecyl sulfate is 151 - 21 - 3. This unique identifier is widely used in the chemical industry for product identification, registration, and safety assessment, ensuring accurate tracking and management of this chemical substance.​

1.3 Molecular Weight​

With a molecular weight of approximately 288.38 g/mol, this value is calculated based on the atomic weights of carbon (C), hydrogen (H), sulfur (S), oxygen (O), and sodium (Na) in its chemical formula. The molecular weight affects its physical and chemical properties, such as solubility and surface activity.​

1.4 Synonyms​

It is also known as SDS, K12, SLS, lauryl sulfate sodium salt, and sodium lauryl sulfate. These synonyms are commonly used in different industries and regions. For example, in the cosmetics and personal care industry, K12 is a frequently used abbreviation, while in scientific research, SDS is more commonly adopted.​

2. Physical and Chemical Properties​

2.1 Appearance​

Sodium dodecyl sulfate typically presents as a white or light - yellow powder. The color may vary slightly depending on the purity and manufacturing process. High - purity products are usually closer to pure white, while those with trace impurities may show a faint yellowish tint.​

2.2 Melting Point​

The melting point of sodium dodecyl sulfate ranges from 204 - 207 °C. This relatively high melting point is related to the strong intermolecular forces in its crystal structure. The presence of ionic and hydrophobic interactions contributes to the stability of the solid state at room temperature.​

2.3 Relative Density​

Its relative density (compared to water) is approximately 1.09. This density value indicates that it is slightly denser than water. When added to an aqueous system, it will sink to some extent, but due to its surfactant properties, it can quickly disperse and interact with water molecules and other substances in the solution.​

2.4 Solubility​

It is highly soluble in water. At room temperature, it can form clear solutions with water, with a solubility of about 150 g/L at 20 °C. This excellent water - solubility is due to the hydrophilic sulfate group in its molecule, which can form hydrogen bonds with water molecules. It is only slightly soluble in ethanol and insoluble in organic solvents such as chloroform and ether.​

2.5 pH Value​

In a 1% aqueous solution, the pH value of sodium dodecyl sulfate is typically in the range of 6.5 - 7.5, which is close to neutral. This pH characteristic makes it suitable for use in a wide range of applications without significantly affecting the acidity or alkalinity of the system.​

3. Technical Indicators​

3.1 Active Content​

The active content of high - quality sodium dodecyl sulfate products is usually ≥92.0%. The active ingredient is the key component that exerts surfactant functions, such as emulsification, foaming, and detergency. Higher active content means better performance and effectiveness in various applications.​

3.2 Moisture Content​

The moisture content is required to be ≤3.0%. Excessive moisture can affect the product's storage stability, physical form, and performance. Strict control of moisture content ensures that the product remains in a stable powder form and maintains its original properties over a long period.​

3.3 Sodium Sulfate Content​

The content of sodium sulfate (an impurity in the product) should be ≤5%. High levels of sodium sulfate can reduce the surfactant activity of sodium dodecyl sulfate and may also have negative impacts on product performance in some applications, such as in the formulation of high - end detergents or cosmetics.​

3.4 Sodium Chloride Content​

The sodium chloride content is typically ≤0.1%. Similar to sodium sulfate, excessive sodium chloride can interfere with the performance of sodium dodecyl sulfate. In applications where high purity is required, such as in pharmaceutical and food - related industries, strict control of sodium chloride content is crucial.​

3.5 Petroleum Ether Soluble Matter Content​

The content of petroleum ether soluble matter is usually ≤1.5%. These soluble substances may be unreacted raw materials or by - products in the production process. Limiting their content is important to ensure the quality and purity of the final product, especially in applications where product purity is of utmost importance.​

4. Product Features​

4.1 Excellent Detergency, Emulsification, and Foaming Power​

Sodium dodecyl sulfate has outstanding detergency. It can effectively remove dirt, oil, and grease from various surfaces. In the presence of water, it can emulsify oils and fats, breaking them into small droplets and dispersing them in the water phase. Moreover, it has excellent foaming properties, capable of generating rich and stable foams, which is widely used in applications such as detergents and personal care products.​

4.2 High Calcium Soap Dispersing Power and Hard - Water Resistance​

It exhibits extremely strong calcium soap dispersing power. In hard water containing high levels of calcium and magnesium ions, it can prevent the formation of calcium and magnesium soaps (which are insoluble and can cause problems like soap scum), ensuring its good performance in hard - water conditions. This makes it suitable for use in areas with hard water resources without significant loss of effectiveness.​

4.3 Good Biodegradability and Mildness to Skin​

Sodium dodecyl sulfate has good biodegradability, with a biodegradation degree of more than 90%. After being discharged into the environment, it can be decomposed by microorganisms over time, reducing its impact on the ecosystem. Although it is an anionic surfactant, it is relatively mild to the skin compared to some other surfactants. However, it still needs to be used with appropriate caution in personal care products to avoid excessive irritation.​

4.4 Good Compatibility​

It has excellent compatibility with anionic and non - ionic surfactants. When combined with other surfactants, it can often produce synergistic effects, enhancing the overall performance of the formulation. For example, in detergent formulations, combining it with non - ionic surfactants can improve cleaning power and foam stability.​

5. Main Applications​

5.1 Detergent and Textile Auxiliary Industry​

It is a major raw material in detergents such as laundry detergents, composite soaps, and dishwashing detergents. In the textile industry, it is used as a bleaching aid and dyeing aid. In laundry detergents, it helps to remove various types of stains on fabrics, while in textile dyeing, it can improve the penetration and fixation of dyes on fibers, resulting in more uniform and fast - colored fabrics.​

5.2 Cosmetics Field​

Sodium dodecyl sulfate is widely used in shampoo, shower gel, facial cleanser, and other cleansing - type cosmetics. In shampoo, it acts as a foaming agent and cleansing agent, helping to remove sebum, dirt, and dandruff from the hair and scalp. In facial cleansers, it can effectively clean the skin surface while maintaining a certain degree of foam, providing users with a good cleaning experience.​

5.3 Food Industry​

According to the provisions of GB 2760 - 96, it can be used as a processing aid in the food industry, such as in cakes, beverages, etc. In cakes, it can improve the texture and volume of the cake by affecting the foaming and emulsification of the batter. In beverages, it may be used to help emulsify flavor oils or stabilize foam - like structures.​

5.4 Pharmaceutical Field​

It can serve as an emulsifier, solubilizer, and skin penetration enhancer for drugs. In pharmaceutical formulations, it can help dissolve poorly - soluble drugs, improve their bioavailability. As a skin penetration enhancer, it can promote the penetration of drugs through the skin, which is beneficial for transdermal drug delivery systems. It is also used as a lubricant and wetting agent in tablets and capsules to facilitate the manufacturing process and improve the dissolution rate of drugs.​

5.5 Other Industries​

In the paper industry, it is used as a cooking penetrant to help chemicals penetrate into wood pulp fibers more effectively during the paper - making process. In the oil - production industry, it can be used as an emulsifier in enhanced oil recovery processes. In the electroplating and coating industries, it is used as a wetting agent and surfactant to improve the adhesion and uniformity of coatings on the substrate surface.​

6. Packaging and Storage​

6.1 Packaging​

It is usually packaged in 25 - kg drums or 20 - kg bags. The packaging materials are selected to ensure good sealing performance to prevent moisture absorption, oxidation, and contamination. For example, the inner layer of the packaging may be a plastic film to prevent moisture penetration, and the outer layer may be a kraft paper bag or a plastic - coated fiber drum for mechanical protection.​

6.2 Storage​

It should be stored in a cool, ventilated, and dry warehouse. It is necessary to pay attention to fire prevention, water - proofing, and moisture - proofing. High temperatures can cause decomposition or changes in its physical and chemical properties. Moisture absorption can lead to clumping and a decrease in product quality. Therefore, storing it in a proper environment can extend its shelf life and maintain its performance.​

7. Safety Information​

7.1 Health Hazards​

Sodium dodecyl sulfate can irritate the mucous membranes and the upper respiratory tract. Inhalation of its dust may cause coughing, shortness of breath, and other respiratory discomfort. It also has an irritating effect on the eyes and skin. Prolonged or excessive contact with the skin may cause redness, itching, and even skin damage. In addition, it may cause allergic reactions in some individuals, especially those with sensitive respiratory systems.​

7.2 Fire and Explosion Hazards​

It is combustible, and when exposed to open flames or high heat, it can burn. When it burns, it may release toxic gases such as sulfur dioxide and sodium oxide. Although it is not highly explosive under normal conditions, in the presence of strong oxidants, it may pose an explosion risk due to chemical reactions. Therefore, appropriate safety measures should be taken during storage and use to prevent fire and explosion accidents.​