Is Sodium Cocoyl Isethionate natural?

Coconut fatty acids esterified with sodium isethionate, itself made from ethylene oxide and mineral sodium bisulfite.

The industrial synthesis of Sodium Cocoyl Isethionate (SCI) is a two-step process. The first step involves the production of sodium isethionate. This is commonly achieved by reacting ethylene oxide with sodium bisulfite in an aqueous solution. This reaction is typically carried out under controlled temperature and pressure conditions to ensure efficient conversion and minimize side reactions. The resulting sodium isethionate is then isolated and purified.

The second and primary step is the esterification of fatty acids with sodium isethionate. The fatty acids are typically derived from the hydrolysis of coconut oil or palm kernel oil, yielding a mixture rich in lauric acid. This fatty acid mixture is then reacted with sodium isethionate. The esterification reaction is usually carried out at elevated temperatures, often in the range of 180-220°C, and can be facilitated by catalysts, although it can also proceed thermally. Water is removed as a byproduct to drive the reaction to completion. The reaction mixture is then cooled and processed to obtain the final SCI product, which is often a powder or flake.

Purification of the final SCI product typically involves steps to remove unreacted starting materials, byproducts such as sodium salts of fatty acids, and residual water. This can include washing, drying, and sometimes recrystallization or other physical separation techniques to achieve the desired purity for cosmetic applications. The final product is a sodium salt of a fatty acid ester of isethionic acid.

Sodium Cocoyl Isethionate, often called SCI, is a popular ingredient in gentle cleansing products like shampoos, facial cleansers, and body washes. It's known for creating a rich, creamy lather while being mild on the skin and hair, making it a great alternative to harsher sulfates. Because it's derived from coconut oil, it's often seen as a more natural choice by consumers.

While the fatty acid part of SCI comes from coconut oil, the other part, called isethionate, is typically made from petrochemicals. This means that while it has renewable origins, it's not entirely natural. The manufacturing process involves combining these two components under heat to create the final ingredient that gives products their excellent cleansing and foaming properties.

CosIng definition: Fatty acids, coco, 2-sulfoethyl esters, sodium salts