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 be c ...
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 more ...
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, emulsifiers, foaming ...
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 use ...
s,
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 ...
s,
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, a ...
, etc.) and for industrial uses. SLES is an inexpensive and very effective
foaming agent
A foaming agent is a material such as a surfactant or a blowing agent that facilitates the formation of foam. A surfactant, when present in small amounts, reduces surface tension of a liquid (reduces the work needed to create the foam) or increase ...
.
[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 Salt ...
(SLS),
ammonium lauryl sulfate
The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary amm ...
(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
Poly ...
are
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, emulsifiers, foaming ...
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 ...
or
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 duri ...
. 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
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 ...
or
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 duri ...
. 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 iso ...
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 quantitie ...
.
The related surfactant
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 Salt ...
(also known as sodium dodecyl sulfate or SDS) is produced similarly, but without the ethoxylation step. SLS and
ammonium lauryl sulfate
The ammonium cation is a positively-charged polyatomic ion with the chemical formula or . It is formed by the protonation of ammonia (). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary amm ...
(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 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 more ...
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, 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>
See also
* Sodium lauroyl sarcosinate
Sodium lauroyl sarcosinate (INCI), also known as sarcosyl, is an anionic surfactant derived from sarcosine used as a foaming and cleansing agent in shampoo, shaving foam, toothpaste, and foam wash products.
This surfactant is amphiphilic due to ...
* Sodium dodecyl 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 sal ...
* Sodium myreth sulfate
Sodium myreth sulfate is a mixture of organic compounds with both detergent and surfactant properties. It is found in many personal care products such as soaps, shampoos, and toothpaste. It is an inexpensive and effective foaming agent. Typical ...
* 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
Poly ...
* Magnesium laureth sulfate
Magnesium laureth sulfate is the magnesium salt of laureth sulfate (2-dodecoxyethylsulfate), which is in turn the ester of laureth (2-dodecoxylethanol) and sulfuric acid. It is used mainly in the chemical industry for the preparation of speciali ...
* Sodium dodecylbenzenesulfonate
Alkylbenzene sulfonates are a class of anionic surfactants, consisting of a hydrophilic sulfonate head-group and a hydrophobic alkylbenzene tail-group. Along with sodium laureth sulfate, they are one of the oldest and most widely used synthet ...
* 1,4-Dioxane, a common impurity of SLES
References
External links
*
{{Authority control
Cosmetics chemicals
Ethers
Household chemicals
Organic sodium salts
Anionic surfactants
Sulfate esters