Ethoxylate

Ethoxylate is a term used for the chemical species produced by the ethoxylation of a substrate with ethylene oxide. In this process, ethylene oxide is added to molecules bearing an active hydrogen, such as alcohols, phenols, or amines, yielding polyoxyethylene chains linked to the original moiety. The resulting products are typically described by the formula R-O-(CH2-CH2-O)n-H, where R is the hydrophobic group and n is the average number of ethoxy units. When neutralized or salted, the products become R-O-(CH2-CH2-O)n-Na+ or other salts.

The most common members are alcohol ethoxylates (AEOs), nonionic surfactants used widely in detergents, cleaners, emulsifiers, and cosmetic products. Their performance depends on the alkyl R tail and the average EO degree n; increasing n increases water solubility and tends to raise the hydrophilic-lipophilic balance (HLB), affecting detergency, foaming, and compatibility.

Manufacture involves catalyzed ethoxylation of the substrate with ethylene oxide, usually under basic conditions using alkali catalysts. The process yields mixtures with distributions of n; commercial products are described by reported average n. Often the final product is neutralized or converted to salts to adjust properties and handling.

Safety and environmental notes: Some ethoxylates may contain trace contaminants such as 1,4-dioxane, a potential carcinogen, requiring purification and testing. Certain ethoxylated substances, particularly older nonionic surfactants like nonylphenol ethoxylates, have faced regulatory restrictions due to environmental or endocrine concerns; modern formulations aim to minimize risks and comply with regulations such as REACH.