Diethanolamine is an organic compound that is both a secondary amine and a diol. A secondary amine is a molecule with two organic groups attached to a nitrogen atom. A diol is a molecule with two alcohol groups. Diethanolamine is produced from the reaction of ethylene oxide with aqueous ammonia. Ethanolamine and triethanolamine are also formed in this reaction. Diethanolamine is soluble in water and some organic solvents. It is a colorless compound, but may appear yellow due to impurities. It has a slight ammonia odor. Solidifies below 28 °C.

The chemical and physical properties of diethanolamine are as follows:

• Its chemical formula is C4H11NO2.
• Its molecular weight is 105.14 g/mol.
• Melting point is 28 °C.
• Its boiling point is 268 °C.
• Its density is 1.096 g/mL.
• Vapor pressure is 0.01 mmHg (at 25 °C).
• Flash point is 134 °C.
• The octanol/water partition coefficient (log Kow) is -1.01.
• Acidity (pKa) is 8.8.
• The pH value is 12.0 (0.1M solution).
• Its solubility is high in water and some organic solvents and low in hydrocarbons.

Diethanolamine has many uses. Most commonly, it is used in cosmetics, pharmaceuticals and personal care products. The purpose of its application in such areas is to act as an emulsifier, foaming agent, pH control agent (acidity regulator). Diethanolamine is used as a solvent for numerous drugs whose aqueous solutions are administered intravenously. Diethanolamine is used as a surfactant in metalworking fluids and oils, as a corrosion inhibitor, as a dispersant in agricultural chemical formulations, and as an intermediate in the production of other compounds such as the widely used diethanolamine fatty acid condensates. Diethanolamine fatty acid condensates are used as emulsifiers, thickeners, wetting agents and detergents in soaps and cosmetics.

Some common products that contain diethanolamine include:

• Shampoos Diethanolamine is used in shampoos as a foaming agent and cleanser. It also helps to adjust the pH of the shampoo and moisturize the hair.
• Cosmetics Diethanolamine is used as an emulsifier and moisturizer in cosmetics. It also helps to improve the structure and texture of cosmetics.
• Pharmaceuticals Diethanolamine is used as a solvent and buffer in pharmaceuticals. It also helps to increase the bioavailability of some drugs.
• Metalworking fluids: Diethanolamine is used as a corrosion inhibitor and lubricant in metalworking fluids. It also helps to remove rust from metal surfaces and increase the efficiency of metalworking processes.
• Agricultural chemicals Diethanolamine is used as an intermediate in the production of agricultural chemicals. For example, iminodiethanol, an intermediate of the herbicide glyphosate, is derived from diethanolamine.

Diethanolamine is also used in industrial gas purification, textile processing, dyes, inks and complexometric titrations. Diethanolamine is a versatile chemical compound and is used for different purposes in many industries.