Is Steareth-20 natural?

Palm-derived stearyl alcohol ethoxylated with 20 mol petrochemical ethylene oxide.

Steareth-20 is a non-ionic surfactant belonging to the polyoxyethylene ether family. Its synthesis involves the ethoxylation of stearyl alcohol (C18H37OH). The process typically occurs in a batch reactor under controlled conditions.

Stearyl alcohol, the starting material, is first dried and then reacted with ethylene oxide (EO) in the presence of a catalyst. Common catalysts include alkaline catalysts such as potassium hydroxide (KOH) or sodium hydroxide (NaOH). The reaction is carried out at elevated temperatures, generally ranging from 120°C to 180°C, and under pressure, typically between 2 to 6 bar, to maintain ethylene oxide in a liquid state and ensure efficient reaction.

The reaction is an addition polymerization where ethylene oxide molecules sequentially add to the hydroxyl group of stearyl alcohol. The '20' in Steareth-20 indicates the average number of ethylene oxide units added per molecule of stearyl alcohol. This average is controlled by the molar ratio of ethylene oxide to stearyl alcohol used in the reaction. The reaction is exothermic and requires careful temperature control to prevent runaway reactions and ensure product consistency.

Following the ethoxylation, the reaction mixture is typically neutralized to remove the alkaline catalyst. This is often achieved by adding an acid, such as acetic acid or phosphoric acid. The crude product is then purified to remove unreacted starting materials, catalyst residues, and by-products. Purification steps may include filtration, vacuum stripping to remove volatile impurities, and sometimes bleaching to improve color. The final product is a waxy solid or viscous liquid, depending on the exact degree of ethoxylation and purity.

Steareth-20 is a type of ingredient commonly used in cosmetics and personal care products to help mix oil and water-based ingredients, making them work together smoothly. Think of it like a bridge that allows oil and water, which normally don't mix, to form a stable blend, like in lotions or creams.

It's made by chemically reacting a fatty alcohol called stearyl alcohol with ethylene oxide. Stearyl alcohol is a fatty substance, and ethylene oxide is a chemical building block. The '20' in its name tells us that, on average, 20 units of ethylene oxide are attached to each molecule of stearyl alcohol. This process is done under specific temperature and pressure conditions using a catalyst. The resulting Steareth-20 helps create the desired texture and stability in products like conditioners, cleansers, and moisturizers.

CosIng definition: Poly(oxy-1,2-ethanediyl), .alpha.-octadecyl-.omega.-hydroxy