Sodium laureth sulfate (SLES), an accepted contraction of sodium lauryl

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again ...

sulfate (SLES), also called sodium alkylethersulfate, is an anionic

detergent A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are m ...

and

surfactant Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsion#Emulsifiers , ...

found in many personal care products (

soap Soap is a salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, soaps are us ...

shampoo Shampoo () is a hair care product, typically in the form of a viscous liquid, that is used for cleaning hair. Less commonly, shampoo is available in solid bar format. Shampoo is used by applying it to wet hair, massaging the product into the ...

toothpaste Toothpaste is a paste or gel dentifrice used with a toothbrush to clean and maintain the aesthetics and health of teeth. Toothpaste is used to promote oral hygiene: it is an abrasive that aids in removing dental plaque and food from the teeth, ...

, etc.) and for industrial uses. SLES is an inexpensive and very effective foaming agent.Kurt Kosswig,"Surfactants" in ''Ullmann's Encyclopedia of Industrial Chemistry'', Wiley-VCH, 2005, Weinheim. SLES,

sodium lauryl sulfate Sodium dodecyl sulfate (SDS) or sodium lauryl sulfate (SLS), sometimes written sodium laurilsulfate, is an organic compound with the formula . It is an anionic surfactant used in many cleaning and hygiene products. This compound is the sodium s ...

(SLS), ammonium lauryl sulfate (ALS), and

sodium pareth sulfate Sodium pareth sulfate is a surfactant found in some detergent products such as hand or body washes, but not as commonly as other chemicals such as sodium laureth sulfate (SLES). It is the sodium salt of a sulfated polyethylene glycol ether. ...

are

s that are used in many cosmetic products for their cleaning and emulsifying properties. It is derived from

palm kernel oil Palm kernel oil is an edible plant oil derived from the kernel of the oil palm tree ''Elaeis guineensis''. It is related to other two edible oils: ''palm oil'', extracted from the fruit pulp of the oil palm, and ''coconut oil'', extracted from ...

coconut oil frameless , right , alt = A cracked coconut and a bottle of coconut oil Coconut oil (or coconut butter) is an edible oil derived from the wick, meat, and milk of the coconut palm fruit. Coconut oil is a white solid fat; in warmer climates du ...

. In herbicides, it is used as a surfactant to improve absorption of the herbicidal chemicals and reduces time the product takes to be rainfast, when enough of the herbicidal agent will be absorbed. Its chemical formula is . Sometimes the number represented by ''n'' is specified in the name, for example laureth-2 sulfate. The product is heterogeneous in the number of ethoxyl groups, where ''n'' is the mean. Laureth-3 sulfate is the most common one in commercial products.

Production

SLES is prepared by

ethoxylation Ethoxylation is a chemical reaction in which ethylene oxide adds to a substrate. It is the most widely practiced alkoxylation, which involves the addition of epoxides to substrates. In the usual application, alcohols and phenols are converted in ...

of dodecyl alcohol, which is produced industrially from

. The resulting ethoxylate is converted to a half ester of sulfuric acid, which is neutralized by conversion to the

sodium Sodium is a chemical element with the symbol Na (from Latin ''natrium'') and atomic number 11. It is a soft, silvery-white, highly reactive metal. Sodium is an alkali metal, being in group 1 of the periodic table. Its only stable ...

salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quant ...

. The related surfactant

(also known as sodium dodecyl sulfate or SDS) is produced similarly, but without the ethoxylation step. SLS and ammonium lauryl sulfate (ALS) are commonly used alternatives to SLES in consumer products.

Safety

Tests in the US indicate that it is safe for consumer use. The Australian government's

Department of Health and Ageing The Australian Federal Department of Health and Ageing was an Government of Australia, Australian government Government department, department that existed between November 2001 and September 2013. The department was created after th ...

and its National Industrial Chemicals Notification and Assessment Scheme (NICNAS) have determined that SLES does not react with DNA.

Irritation

Like many other

s, SLES is an irritant. It has been shown that SLES causes eye or skin irritation in experiments conducted on animals and humans. The related surfactant SLS is also a known irritant.

1,4-Dioxane contamination

Products containing SLES can be contaminated with (up to 300 ppm) of

1,4-dioxane 1,4-Dioxane () is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers ( ...

, a by-product of SLES production. 1,4-Dioxane is classified by the

International Agency for Research on Cancer The International Agency for Research on Cancer (IARC; french: Centre International de Recherche sur le Cancer, CIRC) is an intergovernmental agency forming part of the World Health Organization of the United Nations. Its role is to conduct and ...

as a Group 2B carcinogen: ''possibly carcinogenic to humans''. The

United States Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food s ...

(FDA) recommends that these levels be monitored, and encourages manufacturers to remove 1,4-dioxane, though it is not required by federal law.FDA/CFSAN--Cosmetics Handbook Part 3: Cosmetic Product-Related Regulatory Requirements and Health Hazard Issues
Prohibited Ingredients and other Hazardous Substances: 9. Dioxane
/ref>

References

External links