Diethanolamine

Diethanolamine, often abbreviated as DEA or DEOA, is an organic compound with the formula HN(CH2CH2OH)2. Pure diethanolamine is a white solid at room temperature, but its tendencies to absorb water and to supercool often results in it being found in a colorless, viscous liquid state. Diethanolamine is polyfunctional, being a secondary amine and a diol. Like other organic amines, diethanolamine acts as a weak base. Reflecting the hydrophilic character of the secondary amine and hydroxyl groups, DEA is soluble in water. Amides prepared from DEA are often also hydrophilic. In 2013, the chemical was classified by the International Agency for Research on Cancer as "possibly carcinogenic to humans" (Group 2B).

Production
The reaction of ethylene oxide with aqueous ammonia first produces ethanolamine:
 * C2H4O +  NH3  →  H2NCH2CH2OH

which reacts with a second and third equivalent of ethylene oxide to give DEA and triethanolamine:
 * C2H4O +  H2NCH2CH2OH  →  HN(CH2CH2OH)2
 * C2H4O +  HN(CH2CH2OH)2  →  N(CH2CH2OH)3

About 300M kg are produced annually in this way. The ratio of the products can be controlled by changing the stoichiometry of the reactants.

Uses
DEA is used as a surfactant and a corrosion inhibitor. It is used to remove hydrogen sulfide and carbon dioxide from natural gas.

Diethanolamine is widely used in the preparation of diethanolamides and diethanolamine salts of long-chain fatty acids that are formulated into soaps and surfactants used in liquid laundry and dishwashing detergents, cosmetics, shampoos and hair conditioners. In oil refineries, a DEA in water solution is commonly used to remove hydrogen sulfide from sour gas. It has an advantage over a similar amine, ethanolamine, in that a higher concentration may be used for the same corrosion potential. This allows refiners to scrub hydrogen sulfide at a lower circulating amine rate with less overall energy usage.

DEA is a chemical feedstock used in the production of morpholine.
 * Morpholine from DEA.png

Amides derived from DEA and fatty acids, known as diethanolamides, are amphiphilic.

The reaction of 2-chloro-4,5-diphenyloxazole with DEA gave rise to ditazole. The reaction of DEA and isobutyraldehyde with water removed produces an oxazolidine.

Commonly used ingredients that may contain DEA
DEA is used in the production of diethanolamides, which are common ingredients in cosmetics and shampoos added to confer a creamy texture and foaming action. Consequently, some cosmetics that include diethanolamides as ingredients contain DEA. Some of the most commonly used diethanolamides include:
 * Cocamide DEA
 * DEA-Cetyl Phosphate
 * DEA Oleth-3 Phosphate
 * Lauramide DEA
 * Myristamide DEA
 * Oleamide DEA

Safety and environment
DEA is a potential skin irritant in workers sensitized by exposure to water-based metalworking fluids.

DEA has potential toxicity properties for aquatic species.