Sodium laureth sulfate

Sodium laureth sulfate (SLES), an accepted contraction of 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.[1] SLES, sodium lauryl sulfate (SLS), ammonium lauryl sulfate (ALS), and sodium pareth sulfate are surfactants that are used in many cosmetic products for their cleaning and emulsifying properties. It is derived from palm kernel oil or coconut oil.

Sodium laureth sulfate
Names
IUPAC name
α-Sulfo-ω-(dodecyloxy)-poly(oxyethane-1,2-diyl), sodium salt
Other names
Sodium lauryl ether sulfate
Sodium laureth sulphate
Sodium lauryl ether sulphate
Identifiers
Abbreviations SLES
ChemSpider
  • none
ECHA InfoCard 100.036.281
  • 23665884 (sodium 2-dodecoxyethyl sulfate)
UNII
Properties
CH3(CH2)11(OCH2CH2)nOSO3Na
Molar mass Variable; typically around 420 g/mol
(288.38 + 44.05n) g/mol
Hazards
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
1
2
0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Its chemical formula is CH3(CH2)11(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. Laureth-3 sulfate is common in commercial products.

Production

SLES is prepared by ethoxylation of dodecyl alcohol, which is produced industrially from palm kernel oil or coconut oil. The resulting ethoxylate is converted to a half ester of sulfuric acid, which is neutralized by conversion to the sodium salt.[1] 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.[1]

Safety

Tests in the US indicate that it is safe for consumer use. The Australian government's Department of Health and Ageing and its National Industrial Chemicals Notification and Assessment Scheme (NICNAS) have determined SLES does not react with DNA.[2]

Irritation

Like many other detergents, SLES is an irritant.[3] It has also been shown that SLES causes eye or skin irritation in experiments conducted on animals and humans.[3] The related surfactant SLS is a known irritant.[4][5][6][7]

1,4-Dioxane contamination

Some products containing SLES contain traces (up to 300 ppm) of 1,4-dioxane, which is formed as a by-product during the ethoxylation step of its production. 1,4-Dioxane is classified by the International Agency for Research on Cancer as a Group 2B carcinogen: possibly carcinogenic to humans. The United States Food and Drug Administration (FDA) recommends that these levels be monitored,[8] and encourages manufacturers to remove 1,4-dioxane, though it is not required by federal law.[9]

See also

References
  1. Kurt Kosswig,"Surfactants" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, 2005, Weinheim. doi:10.1002/14356007.a25_747
  2. NICNAS SLES animal test
  3. "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. S2CID 208502361.
  4. 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.
  5. 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.
  6. 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.
  7. 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. S2CID 42092578.
  8. 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. doi:10.1093/jaoac/84.3.666. PMID 11417628.
  9. FDA/CFSAN--Cosmetics Handbook Part 3: Cosmetic Product-Related Regulatory Requirements and Health Hazard Issues. Prohibited Ingredients and other Hazardous Substances: 9. Dioxane
  • Record in the Household Products Database of NLM

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