Diethanolamine (DEA), also known as 2,2'-dihydroxydiethylamine, is an organic compound with the chemical formula C4H11NO2. It is primarily used as an absorbent for acidic gases such as CO2, H2S, and SO2, as a non-ionic surfactant, emulsifier, polishing agent, industrial gas purifier, and lubricant; it is an intermediate in the herbicide glyphosate; used as a purifier for gases and as a raw material in the synthesis of pharmaceuticals and organic compounds. It is an important corrosion inhibitor, applicable in boiler water treatment, automotive engine coolants, drilling and cutting oils, and various other lubricants to inhibit corrosion; under acidic conditions, it serves as an emulsifier for oils and waxes, and as a softening agent for leather and synthetic fibers; in shampoos and light-duty detergents, it is used as a thickener and foam modifier; it also functions as a complexing agent in the electroplating of silver, cadmium, lead, and zinc.