Sulphated surfactants are among the controversial ingredients of the moment, which leads some distribution chains (e. g. Biocoop) to refuse them in the products listed on their shelves. And they are particularly controversial in the organic sector, since, although not exactly natural, they are still authorized by the COSMOS standard. At the Ingredients Meeting organised by Cosmébio on 8 October 2019, Franck Barlerin, Industrial and Scientific Director of Version Organique, took stock of what these “sulphates” are and what puts them in the spotlight.
From a chemical point of view, a sulphate is a molecule that contains a sulphate group SO42- associated with a positive counter ion.
This sulphate can be alone with its counter ion: we are then in the presence of a salt, one of the best known of which is magnesium sulphate MgSO42-.
It can also be grafted to a carbon chain (R, which can range from C4 to C22), giving a generic formula R-SSO42-.
This carbon chain can be of different origins: synthetic, petrochemical or natural, with all possible bio-sourcing, whether animal or plant.
But in all cases, it is necessary to subject it to a sulfonation involving sulphuric acid, followed by additional oxidation to complete its transformation. The R chain, especially when it is long, being lipophilic, and the sulphate group being hydrophilic , the molecules thus obtained are surfactants, of the anionic category.
The use of sulphates in cosmetics
In the form of salt, sulphates are mainly used to stabilize “water-in-oil” emulsions and as an active ingredient (recomposition of marine active ingredients, styling active ingredient, etc.). They are also found in spring and mineral waters.
Present in less than 1% …
