Diethanolamine

2,2`-dihydroxydiethylamine (2,2`-iminodiethanol).

Diethanolamine is an organic compound with an excellent water solubility, alkaline nature and good surface-active properties. It is mostly used as a pH regulator and corrosion inhibitor. Due to a number of its advantages, it is readily used for example in the chemical, construction and textile industries.

General characteristics and properties

Diethanolamine is the INCI name of an organic compound that belongs to the group of weak alkaline amines. Similarly to most ethanolamines, it is produced on an industrial scale, in a reaction of ethylene oxide with excess ammonia.  The substance is also known under its chemical name: 2,2’-Iminodiethanol. The CAS number of the compound is 111-42-2. In products, Diethanolamine mostly acts as a pH regulator.

Physical and chemical properties:

• an oily liquid (at room temperature),
• colourless or light yellow,
• odour of rotten fish or ammonia,
• very well soluble in water, ammonia, methanol and ethanol,
• poorly soluble in ethyl ether and benzene,
• molar mass: approx. 105.1 g/mol,
• density: approx. 1.09 g/ml, at a temperature of 30ᵒC,
• flash point: approx. 170ᵒC.

Role and function of Diethanolamine in the industry

Diethanolamine is known for a wide range of applications in industrial areas. They include its use in chemical synthesis. It is a key raw material for chemical syntheses. Due to its alkaline nature, it can be effectively used to neutralise acidic substances – the capability to change pH is used in the production of metalworking fluids as well as detergents or laundry agents.

Besides, diethanolamine is used as a surfactant and corrosion inhibitor. It can be also used to remove hydrogen sulphide and carbon dioxide from natural gas. The extraction industry conducts a process where hydrogen sulphide is removed using diethanolamine, also known as sweetening. Diethanolamine is also used in the cosmetic industry – it is added for example to shampoos, bath liquids and gels to give them a creamy consistency and a foam effect. Diethanolamine effectively helps to remove dirt and impurities.

In chemical processes, Diethanolamine is used in the production of diethanolamides and diethanolamine salts, long-chain fatty acids, that are subsequently used in soaps and surfactants in dishwashing liquids and detergents.

Diethanolamine is also widely used in the textile processing industry (as a lubricant) and in industrial gas purification to remove acidic gases. It is an anti-corrosion agent in metalworking fluids and chemicals used in agriculture (in the agrochemical industry, Diethanolamine is used as an emulsifier and dispersant).

Aqueous solutions of Diethanoloamine are used as solvents in a number of intravenous drugs. Hair shampoos and dyes may contain free diethanolamine as an ingredient and/or impurity.

Diethanolamine is also added to PUR (polyurethane) foams. The construction industry uses such foams e.g. for (heat) insulation of buildings.