Sodium laureth sulfate
Sodium lauryl ether sulfate; sodium laureth sulphate; sodium lauryl ether sulphate
|Molar mass||around 420 g/mol
(288.38 + 44.05n) g mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
|what is: / ?)(|
Sodium laureth sulfate (SLS), or sodium lauryl ether sulfate (SLES), is an anionic detergent and surfactant found in many personal care products (soaps, shampoos, toothpaste etc.). SLES is an inexpensive and very effective foaming agent. SLES, SLS, ALS and sodium pareth sulfate are surfactants that are used in many cosmetic products for their cleaning and emulsifying properties. They behave similarly to soap.
Its chemical formula is CH3(CH2)10CH2(OCH2CH2)nOSO3Na. 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. It is common for commercial products for n= 3. SLES is prepared by ethoxylation of dodecyl alcohol. The resulting ethoxylate is converted to a half ester of sulfuric acid, which is neutralized by conversion to the sodium salt. The related surfactant sodium lauryl sulfate (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.
SLES is an irritant like many other detergents, with the irritation increasing with concentration. It has also been shown that SLES causes eye or skin irritation in experiments done on animals and humans. The related surfactant SLS is a known irritant, and research suggests that SLES can also cause irritation after extended exposure in some people.
It has long been speculated that the SLS would be carcinogenic, but toxicology research by the U.S. OSHA and IARC supports the conclusions of the Cosmetic, Toiletry, and Fragrance Association (CTFA) and the American Cancer Society that SLES is not a carcinogen. The Australian government's Department of Health and Ageing and its National Industrial Chemicals Notification and Assessment Scheme (NICNAS) have determined SLS does not react with DNA .
Some products containing SLES have been found to also contain traces (up to 279 ppm) of 1,4-dioxane; this is formed as a by-product during the ethoxylation step of its synthesis. The U.S. Food and Drug Administration recommends that these levels be monitored. The U.S. Environmental Protection Agency classifies 1,4-dioxane to be a probable human carcinogen (not observed in epidemiological studies of workers using the compound, but resulting in more cancer cases in controlled animal studies), and a known irritant with a no-observed-adverse-effects level of 400 milligrams per cubic meter at concentrations significantly higher than those found in commercial products. Under Proposition 65, 1,4-dioxane is classified in the U.S. state of California to cause cancer. The FDA encourages manufacturers to remove 1,4-dioxane, though it is not required by federal law.
- Sodium lauroyl sarcosinate
- Sodium dodecyl sulfate
- Sodium myreth sulfate
- Sodium pareth sulfate
- Magnesium laureth sulfate
- Sodium dodecylbenzenesulfonate
- Kurt Kosswig,"Surfactants" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, 2005, Weinheim. doi:10.1002/14356007.a25_747
- "Final report on the safety assessment of sodium laureth sulfate and ammonium laureth sulfate". Journal of the American College of Toxicology 2 (5): 1–34. 1983. doi:10.3109/10915818309140713.
- Agner T (1991). "Susceptibility of atopic dermatitis patients to irritant dermatitis caused by sodium lauryl sulphate". Acta Dermato-venereologica 71 (4): 296–300. PMID 1681644.
- Nassif A, Chan SC, Storrs FJ, Hanifin JM (November 1994). "Abnormal skin irritancy in atopic dermatitis and in atopy without dermatitis". Archives of Dermatology 130 (11): 1402–7. doi:10.1001/archderm.130.11.1402. PMID 7979441.
- Magnusson B, Gilje O (1973). "Allergic contact dermatitis from a dish-washing liquid containing lauryl ether sulphate". Acta Dermato-venereologica 53 (2): 136–40. PMID 4120956.
- Van Haute N, Dooms-Goossens A (March 1983). "Shampoo dermatitis due to cocobetaine and sodium lauryl ether sulphate". Contact Dermatitis 9 (2): 169. doi:10.1111/j.1600-0536.1983.tb04348.x. PMID 6851541.
- NICNAS SLES animal test
- Black RE, Hurley FJ, Havery DC (2001). "Occurrence of 1,4-dioxane in cosmetic raw materials and finished cosmetic products". Journal of AOAC International 84 (3): 666–70. PMID 11417628.
- 1,4-Dioxane (1,4-Diethyleneoxide). Hazard Summary. U.S. Environmental Protection Agency. Created in April 1992; Revised in January 2000. Fact Sheet
- "1,4-Dioxane cancer 123-91-1 January 1988" (PDF). Office of Environmental Health Hazard Assessment.
- "California Files Prop 65 Lawsuit Against Whole Foods, Avalon". Bloomberg.
- FDA/CFSAN--Cosmetics Handbook Part 3: Cosmetic Product-Related Regulatory Requirements and Health Hazard Issues. Prohibited Ingredients and other Hazardous Substances: 9. Dioxane