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Ethoxylation is a chemical process that creates surfactants used in many commercial products, including biochemistry and medicine. Compounds like nonylphenol, amines, fatty acids, and fatty alcohols are commonly ethoxylated. Surfactants are found in detergents, shampoos, paints, inks, pesticides, and more. PEGylation is a specific type of ethoxylation used in medicine to promote drug delivery. Some ethoxylated materials, like nonylphenol ethoxylates, are hazardous and regulated in some countries due to their toxic effects on aquatic life and reproductive problems in animals.
Ethoxylation is a chemical process used in industry to create surfactants, compounds that reduce the surface tension of liquids. The ethoxylation process involves adding ethylene oxide to an alcohol or phenol to make products. Many products produced by ethoxylation have commercial applications and some are used in biochemistry and medicine. While most surfactants can be widely used, others are dangerous to humans and the environment, and their use is restricted in some countries.
Compounds that are commonly ethoxylated include nonylphenol, amines, fatty acids and fatty alcohols. A catalyst such as potassium hydroxide must usually be added together with the ethylene oxide to speed up the ethoxylation reaction. Some compounds, such as lactic acid and 12-hydroxystearic acid, can be ethoxylated without a catalyst.
In industrial plants, ethoxylation can involve a pre-treatment step where water is removed to prevent the formation of foreign compounds and a post-treatment step where the catalyst is neutralized and removed. The various steps of the reaction can take place in different vessels, or in a large reactor. The design of the reaction depends on the efficiency. Industrial chemists often directly monitor the ethoxylation process and make changes to increase productivity.
The products of ethoxylation are known as ethoxylated materials or surfactants. These are organic compounds that contain both hydrophilic (water attractant) and hydrophobic (water repellent) groups. Surfactants modify the surface properties of liquids because their structure causes them to migrate towards the liquid boundary interface. For example, in water, the surfactants will migrate towards the air-water boundary, but in an oil-water mixture, the surfactants will migrate towards the oil-water boundary. The term surfactant is a shortened version of the term surfactant agent, reflecting this behavior.
Surfactants are found in detergents, shampoos, paints, inks, pesticides and many other commercial products. They are typically used as emulsifiers, causing otherwise unmixable liquids to mix, or as foaming and cleaning agents. Some surfactants have biochemical applications and are used to extract proteins from cells or make proteins soluble in solution.
A specific type of ethoxylation, known as PEGylation, is used in medicine to promote drug delivery into the body. In PEGylation, polyethylene glycol chains are attached to a protein or therapeutic drug. This prevents the body’s immune system from recognizing and attacking the drug or protein, and also allows normally insoluble drugs to become water soluble.
Some ethoxylated materials can be hazardous and are currently regulated by some government agencies. Nonylphenol ethoxylates (NPE), used in pesticides, industrial cleaners and some household cleaning products, can reach groundwater and soil via the sewage system. NPEs have toxic effects on aquatic life and also cause reproductive problems in animals. Concern about the possibility that NPEs could migrate through agricultural land to human food has led to restrictions on their use in several countries.
