What is Sodium Isethionate?
Sodium isethionate is the organic salt isethionic acid (C2H6O4S), which is an organosulfur compound that has many uses throughout the home and personal care industries. Isethionic acid was originally discovered in 1833 upon reacting solid sulphur trioxide with ethanol, which can then be neutralized to form the sodium salt.
Since the discovery of isethionic acid in the 19th century, the production of sodium isethionate has become more efficient. Currently, the most proficient route to the sodium salt of isethionic acid (C2H5O4SNa) is via the ethoxylation of sodium sulfites and their derivatives. The product of this reaction yields a small molecule comprised of an alkylsulfonic acid coupled to a hydroxyl functional group (beta position, Figure 1).
The unique pairing of these two chemical structures allows sodium isethionate to be utilized as a versatile compound throughout the home and personal care industries because it acts as an amphoteric detergent and can also be used as an intermediate in the preparation of surfactants derived from fatty acid sulphoalkyl esters (acyloxyethanesulfonates).
Oxiteno is bringing its expertise in ethoxylation and its global manufacturing capabilities to the US market to produce high quality isethionate products. With a new production facility located in Pasadena, TX, Oxiteno intends to be one of the leading chemical manufacturers in the US for premium sodium isethionate and isethionate derivatives.
Oxiteno’s ULTRADET ITS and ULTRADET ITS LS benefit the home and personal care markets because of their ability to increase formulation stability, enhance detergency in hard water, and for their mild effect on skin. For these reasons, sodium isethionates are commonly used to formulate soap bars and shampoos in the personal care chemicals market.
Some benefits of using Oxiteno’s ULTRADET ITS and ULTRADET ITS LS in soap formulations include a reduction in soap residue on the skin (as this line of sodium isethionates is readily rinsed off during washing), enriched lather made by the soap and it can serve as an anti-static agent in shampoos.
What Are Acyloxyethanesulfonates (Sodium Cocoyl-Isethionate or Sodium Lauroyl-Isethionate)?
In addition to being a stand-alone additive to moisturizing soap bars, sodium isethionate is often used as a precursor in the production of the sulphoalkyl esters of fatty acids (acyloxyethanesulfonates). In the production of acyloxyethanesulfonates (Figure 2), the hydroxyl moiety on the sodium isethionate is utilized to esterify biorenewable fatty acids (e.g. coconut fatty acid), producing a compound that contains a hydrophilic (isethionate) and hydrophobic (fatty acid carbon chain) portion.
Compounds consisting of two groups that have varying ‘opinions’ of water are commonly referred to as surfactants because they have the unique ability to reduce the surface energy of immiscible phases (i.e. oil-and-water). The combination of the isethionate functionality with the fatty acid makes this class of biodegradable surfactants excellent cleansing agents that are very effective in hard water conditions.
What makes these acyloxyethanesulfonates different from surfactants of similar structures, for instance sodium lauryl sulfate and sodium laureth sulfate, is their lower propensity to cause skin irritation (as compared to similar structures derived from sulfates).1 These mild cleansing agents are designed from bio-renewable sources, making them an eco-friendly alternative to other synthetic surfactants.
Sodium cocoyl- and lauroyl-isethionates are very often used in personal care formulations because this compound combines good detergency and wetting properties with high foaming capabilities in soft and hard waters. Soap bars that contain acyloxyethanesulfonates are not required to have an alkaline pH like most soap bars based on the saponification of triglycerides. Lowering the pH of the soap bar while maintaining a high level of detergency and lather can be accomplished using acyloxyethanesulfonates, resulting in a milder effect on skin, which is commonly at pH of 5.5-6.5.
With a new production site located near Houston, TX, Oxiteno intends to produce isethionates in the US for the first time, affording a cost-effective, premium alternative for soap and shampoo formulators. For more information regarding Oxiteno’s line of sodium isethionates, please contact us today.
1- Belsito, Donald V., et al. “Amended Safety Assessment of Isethionate Salts as Used in Cosmetics.” (2013).