Shampoo Chemistry

How Surfactants Are Made

This is for everyone who would like to know how those "other" soaps are made! Some of this information is from The American Cleaning Institute web site.


A detergent is an effective cleaning product because it contains one or more surfactants. Because of their chemical makeup, the surfactants used in detergents can be engineered to perform well under a variety of conditions. Such surfactants are less sensitive than soap to the hardness minerals in water and most will not form a film. Detergent surfactants were developed in response to a shortage of animal and vegetable fats and oils during World War I and World War II. In addition, a substance that was resistant to hard water was needed to make cleaning more effective. At that time, petroleum was found to be a plentiful source for the manufacture of these surfactants. Today, detergent surfactants are made from a variety of petrochemicals (derived from petroleum) and/or oleochemicals (derived from fats and oils).

Petrochemicals and Oleochemicals

Like the fatty acids used in soapmaking, both petroleum and fats and oils contain hydrocarbon chains that are repelled by water but attracted to oil and grease in soils. These hydrocarbon chain sources are used to make the water-hating end of the surfactant molecule.

Other Chemicals

Chemicals, such as sulfur trioxide, sulfuric acid and ethylene oxide, are used to produce the water-loving end of the surfactant molecule.


As in soapmaking, an alkali is used to make detergent surfactants. Sodium and potassium hydroxide are the most common alkalis.

How Detergent Surfactants Are Made

Anionic Surfactants

The chemical reacts with hydrocarbons derived from petroleum or fats and oils to produce new acids similar to fatty acids. A second reaction adds an alkali to the new acids to produce one type of anionic surfactant molecule.

Nonionic Surfactants

(this includes those made with glucose and coconut oil) Nonionic surfactant molecules are produced by first converting the hydrocarbon to an alcohol and then reacting the fatty alcohol with ethylene oxide (ethoxylated). These nonionic surfactants can be reacted further with sulfur-containing acids to form another type of anionic surfactant.
----- Ethoxylated-----
Surfactants that have been "Ethoxylated" have been chemically combined with the compound "ethylene oxide". When you see the word 'laureth', it means it is ethoxylated. Tear-free shampoos are all ethoxylated. These ethoxylated surfactants are used in baby shampoos. They are considered slightly milder because the molecules are larger. The more ethylene oxide you add, the larger the molecule becomes. The idea is to make the molecule large enough so that it won't irritate the skin or eyes, but this effect is negligible in most cases. The more ethoxylation, the greater the risk of exposure to harmful carcinogens, nitrosamines, and/or 1,4 dioxane. In the process of ethoxylation, a by-product called 1,4 dioxane can be released. 1,4 dioxane is a known carcinogen that reacts with other ingredients in shampoos to form dangerous nitrates. These nitrates are capable of permeating through intact skin each time you shampoo. Dr. John Baily, of the FDA reported many shampoos, bubble baths, creams and lotions contain "excessively high" levels of 1,4 dioxane. Relying on the National Cancer Institute clinical tests showing that 1,4 dioxane causes liver damage in animals, Dr. Baily went on to say that the higher degree of ethoxylation, the more likely of the occurrence of 1,4 dioxane. Dr. Baily expressed concern that the levels of 1,4 dioxane has "not significantly dropped" in the 10 years since this information was first released. Products for children and babies usually use highly ethoxylated ingredients. Unfortunately, parents permit their babies to sit for long periods of time in bubble baths, or use "no tear" baby shampoos - possibly exposing their children to these dangerous elements. We advise that you keep young children away from harsh and highly ethoxylated surfactants. ---------------


These types of energy interact and should be in proper balance. Let's look at how they work together. Let's assume we have oily, greasy soil on clothing. Water alone will not remove this soil. One important reason is that oil and grease present in soil repel the water molecules. Now let's add soap or detergent. The surfactant's water-hating end is repelled by water but attracted to the oil in the soil. At the same time, the water-loving end is attracted to the water molecules. These opposing forces loosen the soil and suspend it in the water. Warm or hot water helps dissolve grease and oil in soil. Washing machine agitation or hand rubbing helps pull the soil free.