α-Olefin sulfonates (also: alpha-olefin sulfonates or AOS) are a group of anionic surfactants, which are used as detergents.[1] The compounds contain a - mostly linear, primary - alkyl R and a monovalent cation M, preferably sodium.[2] The most frequently used example of this group of substances is sodium α-olefin sulfonate (INCI: Sodium C14-16 Olefin Sulfonate).[3]
R= Alkyl, M= Na+, n = 1 or 2
Production and composition
editα-Olefin sulfonates are produced by sulfonation of alpha-olefins, typically using sulfur trioxide. This reaction produces two groups of products: (1) allylic and homoallylic sulfonic acids and (2) 5- and 6-membered cyclic sulfate esters. Base hydrolysis of the mixture gives alkene sulfonates (derived from simple deprotonation of allylic and homoallylic sulfonic acids) and 3- and 4-hydroxyalkanesulfonates (derived from the cyclic sulfate esters).[4] A typical mixture consists of 60-65% alkene sulfonates and 35-40% hydroxyalkane sulfonates. The commercially available olefin sulfonates are supplied as solutions containing about 40% active ingredient content.[5][6]
Description
editIn addition to a longer hydrocarbon chain in which there must be at least one double bond (hence the name "olefin"), it has an anionic sulfonate headgroup with a sodium ion as a counterion. The sulfonate group is negative in aqueous solution, which is why the α-olefin sulfonates are among the anionic surfactants. In contrast to most other surfactants in which the C12-alkyl chains have the highest surface activity, olefin sulfonates shows maximal activity when using C14and C16-olefins.[5]
Usage
editα-Olefin sulfonates with linear alkenyl radicals from C12 to C18 are used as anionic surfactants in various areas of application due to their pronounced foam formation[clarification needed] and foam stability (even with high water hardness), excellent fat-dissolving power and oil dissolving power as well as a favorable ecological profile and low aquatic toxicity and human toxicity.[7][8] They are typically used in detergents and cleaning agents, for degreasing, in the emulsion polymerization, the conditioning of concrete and mortar as well as in the formulation of pesticides.[2]
Sodium C14-16 olefin sulfonate is being introduced in some shampoos as an alternative to sodium laureth sulfate. Some groups and sellers suggest that it is healthier, but this claim lacks evidence.[9]
References
edit- ↑ Raney, Kirk H.; Shpakoff, Paul G.; Passwater, Deborah K. (1998). "Use of high-active alpha olefin sulfonates in laundry powders". Journal of Surfactants and Detergents. 1 (3): 361–369. doi:10.1007/s11743-998-0037-z. ISSN 1558-9293. S2CID 93700546.
- 1 2 Entry on α-Olefin Sulfonate. at: Römpp Online. Georg Thieme Verlag, retrieved 6 July 2019.
- ↑ External identifiers of or database links to Sodium C14-16 olefin sulfonate: CAS-Number: 68439-57-6, EC Number: 270-407-8, ECHA-InfoCard: 100.063.987, Wikidata: Q72507735.
- ↑ Holmberg, Krister (2019). "Surfactants". Ullmann's Encyclopedia of Industrial Chemistry. pp. 1–56. doi:10.1002/14356007.a25_747.pub2. ISBN 978-3-527-30673-2.
- 1 2 Williams, D. F.; Schmitt, W. H. (1996). Chemistry and Technology of the Cosmetics and Toiletries Industry (Second ed.). Dordrecht: Springer Netherlands. p. 6. ISBN 978-94-009-1555-8. OCLC 840304608.
- ↑ Marquis, D. M.; Sharman, S. H.; House, R.; Sweeney, W. A. (November 1966). "Alpha olefin sulfonates from a commercial SO 3 -Air reactor". Journal of the American Oil Chemists' Society. 43 (11): 607–614. doi:10.1007/BF02640797. S2CID 84061525.
- ↑ Nair, Bindu (1 October 1998). "Final Report On the Safety Assessment of Sodium Alpha-Olefin Sulfonates". International Journal of Toxicology. 17 (5_suppl): 39–65. doi:10.1177/109158189801700504. ISSN 1091-5818. S2CID 208152005.
- ↑ "Re-Review of Sodium α-Olefin Sulfonates as Used in Cosmetics | Cosmetic Ingredient Review". www.cir-safety.org. Retrieved 6 July 2019.
- ↑ Cline, A.; Uwakwe, L.N.; McMichael, A.J. (January 2018). "No sulfates, no parabens, and the "no-poo" method: a new patient perspective on common shampoo ingredients". Cutis. 101 (1): 22–26. PMID 29529111.