Sodium Laureth Sulfate CAS：1335-72-4
Outstanding Cleaning Efficiency:Sodium Laureth Sulfate (SLES) markedly reduces water surface tension, delivering strong removal performance against grime and various contaminants.
Rich and Stable Foaming:Its special molecular structure allows SLES to produce plentiful and long-lasting foam, ideal for use in personal care and cleaning product formulas.
Hard Water Compatibility:It retains high cleaning efficiency in hard water environments, guaranteeing consistent performance with different water quality conditions.
Wide-Ranging Emulsifying Ability:Featuring strong emulsifying performance, SLES is commonly incorporated into many products such as cosmetics, shampoos, soaps and detergent formulations.
1. Product Overview
Sodium Laureth Sulfate, commonly known as SLES, is a potent anionic surfactant that ranks among the most extensively applied detergent raw materials worldwide. It is derived through the ethoxylation of sodium lauryl sulfate (SLS), with polyoxyethylene segments inserted between the lauryl alcohol structure and the sulfate functional group.
The term “laureth” is a condensed form of “lauryl ether”, which precisely describes its chemical makeup as sodium lauryl ether sulfate. SLES exists as an oligomeric blend, generally featuring an average of 1 to 3 ethylene oxide groups; among commercial products, the 2-mole and 3-mole ethoxylated grades are the most prevalent.
Its molecular formula is generally expressed as CH₃(CH₂)ₙCH₂(OCH₂CH₂)ₓOSO₃Na, with n ranging from 10 to 13 and x averaging between 1 and 3. Relevant CAS registries include 9004-82-4 for polymeric grades and 68891-38-3 for specialized C12-14 alkyl ether types.
SLES usually presents as a transparent to faintly turbid liquid, with hues varying from colorless and light yellow to amber, based on its concentration and product grade. It is highly valued for its outstanding foaming performance, milder nature relative to SLS, strong adaptability to hard water, and convenient viscosity adjustment in formula systems.
Acting as a core surfactant in personal care manufacturing, SLES serves as the main cleansing ingredient in a vast number of shampoos, shower gels, hand soaps and facial cleansers. It also acts as an essential ingredient in many household cleaning and industrial detergent products.
2. Key Features
Excellent Foaming Performance: Generates dense and long-lasting foam with fast initial foaming ability, even when used in hard water. Among its types, the 2-mole ethoxylate grade stands out for stable foaming under various water hardness levels.
Milder Than SLS: Compared with regular sodium lauryl sulfate (SLS), the ethoxylated structure greatly lowers irritation to skin and eyes, making it ideal for personal care products designed for daily use.
Strong Viscosity Adjustment Performance: Can be easily thickened using common additives including sodium chloride, cocamidopropyl betaine and other betaines, as well as alkanolamides, helping formulators reach target texture and consistency efficiently.
Strong Resistance to Hard Water: Retains full cleaning and foaming performance in both soft and hard water environments, avoiding the soap scum issue typical of conventional soap products. Wide Compatibility: Mixes well with anionic, nonionic and amphoteric surfactants, along with alkaline additives, supporting the development of diversified and multi-functional formulations. Environmentally Friendly: Features good biodegradability, complying with relevant environmental requirements for surfactant raw materials.
Diverse Concentration Specifications: Supplied in various active content levels, commonly 25–28%, 60% and 70%, to match different formulation designs and production conditions. C
ontrolled 1,4-Dioxane Content: Modern production technology supports low-dioxane grades, with 1,4-dioxane limited to below 10 ppm or even below 5 ppm, effectively reducing safety risks related to this byproduct.
3. Technical Specifications with Explanations
| Parameter | Typical Value/Specification | Description & Significance |
| CAS Numbers | 9004-82-4 (polymer) | Universal chemical identifiers. 68891-38-3 is most common for commercial SLES. |
| 68891-38-3 (C12-14 alkyl ethers) | ||
| INCI Name | Sodium Laureth Sulfate | International Nomenclature of Cosmetic Ingredients designation. |
| Molecular Formula | C₁₈H₃₇NaO₇S (n=3 average) | Represents the ethoxylated structure with variable alkyl chain lengths. |
| CH₃(CH₂)ₙCH₂(OCH₂CH₂)ₓOSO₃Na | ||
| Molecular Weight | ~420.54 g/mol (n=3 average) | Varies with ethylene oxide content. |
| Appearance | Clear to slightly hazy liquid (low-active) | Visual quality indicator varies by concentration and grade. |
| Yellow to dark amber liquid | ||
| Homogenous smooth paste (high-active) | ||
| Active Matter Content | 25-28% (low-active grades) | Core specification. Higher concentrations offer lower shipping costs but require different handling. |
| 60% (medium-active) | ||
| 70% (high-active grades) | ||
| Ethylene Oxide (EO) Content (average moles) | 2.0 moles | Determines mildness and performance characteristics; 2-mol offers excellent foam, 3-mol offers enhanced mildness. |
| 3.0 moles | ||
| pH (10% aqueous) | 6.0 - 8.5 | Near-neutral pH suitable for personal care formulations. |
| Density (at 25°C) | ~1.03 - 1.04 g/mL | Slightly heavier than water; used for volume-to-weight conversions. |
| Viscosity (at 25°C) | Varies with concentration and grade | Varies significantly with active content and temperature. |
| Flash Point | ≥94°C (low-active grades) | High-active grades may contain solvents (ethanol) and have lower flash points. |
| ~26°C (some 60% grades) | ||
| Pour/Freeze Point | ~ -2°C to 4°C | Indicates low-temperature handling characteristics. May solidify at low temperatures; gentle warming and agitation restore homogeneity. |
| Sodium Chloride (NaCl) Content | ≤ 0.2% | Residual salt from manufacturing; higher levels affect viscosity response. |
| Sodium Sulfate (Na₂SO₄) Content | ≤ 0.5% | Byproduct of sulfation process; controlled for purity. |
| Unsulfated Matter Content | ≤ 3.0% | Measures non-sulfated organic matter; lower values indicate higher purity. |
| 1,4-Dioxane Content | <3 ppm to <50 ppm (grade dependent) | Critical quality parameter. Process impurity with regulatory limits; low-dioxane grades meet strict requirements. |
| <5 ppm (low dioxane grades) | ||
| VOC Content | 0-14% (grade dependent) | Volatile Organic Compounds; some high-active grades contain ethanol as solvent. |
| Biodegradability | Readily biodegradable | Meets environmental safety standards. |
| Oral Toxicity (LD₅₀) | >5 g/kg (rat) | Practically non-toxic orally. |
| Skin/Eye Irritation | Mild to moderate (10% active) | Less irritating than SLS; avoid eye contact. |
4. Applications
Personal Care & Cosmetics
Home Care
Industrial & Institutional Cleaning
Industrial Applications
Emulsion Polymerization: Serves as a surfactant in the production of polymer materials.
