A detergent is a surfactant or a mixture of surfactants with cleansing properties in dilutesolutions. These substances are usually alkylbenzene sulfonates, a family of compounds that are similar to soap but are more soluble in hard water, because the polar sulfonate is less likely than the polar carboxylate to bind to calcium and other ions found in hard water. In domestic contexts, the term detergent by itself refers specifically to laundry detergent or dish detergent, as opposed to hand soap or other types of cleaning agents. Detergents are commonly available as powders or concentrated solutions. Detergents, like soaps, work because they are amphiphilic: partly hydrophilic and partly hydrophobic. Their dual nature facilitates the mixture of hydrophobic compounds with water. Because air is not hydrophilic, detergents are also foaming agents to varying degrees.
Etymology
"Detergent" is borrowed from the Latin verb "detergere", which is a compound of de, "away from", and tergere, "to wipe". In the English language, it was used as an adjective, "detergent", in the 17th century.
Chemical classifications of detergents
Detergents are classified into three broad groupings, depending on the electrical charge of the surfactants.
Anionic detergents
Typical anionic detergents are alkylbenzenesulfonates. The alkylbenzene portion of these anions is lipophilic and the sulfonate is hydrophilic. Two different varieties have been popularized, those with branched alkyl groups and those with linear alkyl groups. The former were largely phased out in economically advanced societies because they are poorly biodegradable. An estimated 6 billion kilograms of anionic detergents are produced annually for domestic markets. Bile acids, such as deoxycholic acid, are anionic detergents produced by the liver to aid in digestion and absorption of fats and oils. , and a soap.
Non-ionic detergents are characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on polyoxyethylene or a glycoside. Common examples of the former include Tween, Triton, and the Brij series. These materials are also known as ethoxylates or PEGylates and their metabolites, nonylphenol. Glycosides have a sugar as their uncharged hydrophilic headgroup. Examples include octyl thioglucoside and maltosides. HEGA and MEGA series detergents are similar, possessing a sugar alcohol as headgroup. Zwitterionic detergents possess a net zero charge arising from the presence of equal numbers of +1 and −1 charged chemical groups. Examples include CHAPS. See surfactants for more applications.
One of the largest applications of detergents is for household and shop cleaning including dish washing and washing laundry. The formulations are complex, reflecting the diverse demands of the application and the highly competitiveconsumer market.
Fuel additives
Both carburetors and fuel injector components of Otto engines benefit from detergents in the fuels to prevent fouling. Concentrations are about 300 ppm. Typical detergents are long-chain amines and amides such as polyisobuteneamine and polyisobuteneamide/succinimide.
