ALKYL (OR ALCOHOL) ETHOXY SULPHATE (AES)

Alkyl ethoxy sulphates or alcohol ethoxy sulphates (AES) are a widely used class of anionic surfactants. They are commonly used in household cleaning products, personal care products, institutional cleaners and industrial cleaning processes, as industrial process aids in emulsion polymerization and as additives during plastics and paint production. (Ref: HERA)

  • Function and benefits

    What is its function and benefits?
    Alkyl ethoxy sulphates (AES) are a surfactant or surface active agent which is a substance that is used to change the surface tension of water to assist cleansing, wetting surfaces, foaming and emulsifying (the suspension of one liquid evenly within another). (Ref: Cleanright). As anionic surfactants, AES are particularly effective at oily soil cleaning and oil/clay soil suspension. (Ref: Cleanright)

    How does it work?
    As a surfactant, alkyl ethoxy sulphates (AES) give a product, when dissolved in water, the ability to remove dirt from surfaces such as the human skin, textiles, and other solids.
    Because they are anionic, AES can react in the wash water with the positively charged water hardness ions (calcium and magnesium), which can lead to partial deactivation. (Ref: Cleanright)
    To know more about surfactants, visit its definition in the SIB Glossary.

  • Chemical structure and composition

    The structure beside is an example of AES with the structure C12EO3S:

    Alkyl Ethoxy Sulphates structure

    There are several CAS numbers describing Alkyl Ethoxy Sulphates (AES).
    Commercial Alkyl Ethoxy Sulphates (AES) mixtures consist largely of linear primary alcohol ethoxy sulphates with the basic structure
    CH3(CH2)n (OCH2)mOSO4X
    where n can vary between 11 and 17 and m varies from 0 to 8 with X most often being sodium. The AES used in laundry detergents typically has an n = 11 - 14 and an average m < 3.

  • Product / Category: where is it used?

    Alkyl Ethoxy Sulphates (AES) mixtures are used in household cleaning products, personal care products, institutional cleaners and industrial cleaning processes. They are used in laundry detergents, hand dishwashing liquids, and various hard surface cleaners. They also are used as process aids and additives in the production of plastics and paints.
  • Ingredient safety and information

    AISE-CEFIC published a human and environmental risk assessment for alkyl ethoxy sulphates. The aquatic toxicity of alkyl ethoxy sulphates (AES) has been reviewed by several authors. The large number of acute and chronic values reported for various homologues and mixtures reveal that no particular species is uniquely sensitive to AES. Depending on the exact variant, AES toxicity ranges from very toxic (EC50 below 1 mg per litre in short-term tests) to not harmful (EC50 above 100 mg per litre) to aquatic organisms.
    Alkyl ethoxy sulphates (AES) mixtures with a wide range of homologue distributions are readily biodegradable. AES degradation has been demonstrated in raw sewage, activated sludge, river water, estuarine water and soil. AES degradation does not produce any persistent metabolites and the aquatic toxicity decreases over the course of the degradation.
    Ingredient information sheet (PDF file)
    Read the full risk assessment in www.heraproject.com

  • References

    • Belanger, S.E., Meiers, E.M. and Bausch, R.G., 1995, Direct and Indirect Ecotoxicological Effects of Alkyl Sulfate and Alkyl Ethoxysulfate on Macroinvertebrates in Stream Mesocosms. Aquatic Toxicology, 33, pp.65-87.
    • Dyer, S.D., Stanton, D.T., Lauth, J.R. and Cherry, D.S., 2000, Structure-activity relationships for acute and chronic toxicity of alcohol ether sulfates. Environmental Toxicology and Chemistry, 19, pp.608-616.
    • Federle, T.W., Gasior, S.D. and Nuck, B.A., 1997, Extrapolating mineralization rates from the ready CO2 screening test to activated sludge, river water, and soil. Environmental Toxicology and Chemistry, 16(2), pp.127-134.
    • Matthijs et al., 1999, Environmental Toxicology and Chemistry, 19, pp.2635-2644.
    • Nuck, B.A. and Federle, T.W., 1996, A batch test for assessing the mineralisation of 14C-radiolabeled compounds under realistic conditions. Environmental Toxicology and Chemistry, 30, pp.3597-3603.
    • van de Plassche, E.J. et al., 1999, Predicted No-Effect Concentrations and Risk Characterization of Four Surfactants: Linear Alkyl Benzene Sulfonate, Alcohol Ethoxylates, Alcohol Ethoxylated Sulfates, and Soap. Environmental Toxicology and Chemistry, 18(11), pp.2653-2663.
    • Yoshirmura, K. and Masuda, F., 1982, Biodegradation of Sodium Alkyl Poly(oxyalkylene)sulfates, Journal of the American Oil Chemists' Society, 59, pp.328-332.
    • HERA, 2003, Human & Environmental Risk Assessment on ingredients of European household cleaning products, Alcohol Ethoxysulphates (AES). [online] Available at: http://www.heraproject.com/RiskAssessment.cfm?SUBID=1 [Accessed November 17, 2011]
    • Cleanright website: http://uk.cleanright.eu

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