Detergent
Overview
 
A detergent is a surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...

 or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap
Soap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...

 but are less affected by hard water
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...

. In most household contexts, the term detergent by itself refers specifically to laundry detergent
Laundry detergent
Laundry detergent, or washing powder, is a substance that is a type of detergent that is added for cleaning laundry. In common usage, "detergent" refers to mixtures of chemical compounds including alkylbenzenesulfonates, which are similar to soap but are less affected by "hard water." In most...

or dish detergent, as opposed to hand soap or other types of cleaning agents.
Discussions
Encyclopedia
A detergent is a surfactant
Surfactant
Surfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...

 or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap
Soap
In chemistry, soap is a salt of a fatty acid.IUPAC. "" Compendium of Chemical Terminology, 2nd ed. . Compiled by A. D. McNaught and A. Wilkinson. Blackwell Scientific Publications, Oxford . XML on-line corrected version: created by M. Nic, J. Jirat, B. Kosata; updates compiled by A. Jenkins. ISBN...

 but are less affected by hard water
Hard water
Hard water is water that has high mineral content . Hard water has high concentrations of Ca2+ and Mg2+ ions. Hard water is generally not harmful to one's health but can pose serious problems in industrial settings, where water hardness is monitored to avoid costly breakdowns in boilers, cooling...

. In most household contexts, the term detergent by itself refers specifically to laundry detergent
Laundry detergent
Laundry detergent, or washing powder, is a substance that is a type of detergent that is added for cleaning laundry. In common usage, "detergent" refers to mixtures of chemical compounds including alkylbenzenesulfonates, which are similar to soap but are less affected by "hard water." In most...

or dish detergent, as opposed to hand soap or other types of cleaning agents. Detergents are commonly available as powders or concentrated solutions. Detergents work because they are amphiphilic - partly hydrophilic (polar) and partly hydrophobic (non-polar). Their dual nature facilitates the mixture of hydrophobic compounds (like oil and grease) with water. Because air is not hydrophillic, detergents are also foaming agent
Foaming agent
A foaming agent is a surfactant, which when present in small amounts, facilitates the formation of a foam, or enhances its colloidal stability by inhibiting the coalescence of bubbles....

s to varying degrees. Completely non-polar solvents known as degreasers can also remove hydrophobic contaminants but may not dissolve in water because of a lack of polar elements.

Chemical classification of detergents

Detergents are classified into three broad groupings, depending on the electrical charge of the surfactants.

Anionic detergents

Typical anionic detergents are alkylbenzenesulfonates
Sodium dodecylbenzenesulfonate
Sodium dodecylbenzenesulfonate is a series of organic compounds with the formula C12H25C6H4SO3Na. It is a colourless salt with useful properties as a surfactant. It is usually produced as a mixture of related sulfonates...

. The alkylbenzene portion of these anions is lipophilic and the sulfonate is hydrophilic. Two 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
Deoxycholic acid
Deoxycholic acid, also known as deoxycholate, cholanoic acid, and 3α,12α-dihydroxy-5β-cholanate, is a bile acid. Deoxycholic acid is one of the secondary bile acids, which are metabolic byproducts of intestinal bacteria. The two primary bile acids secreted by the liver are cholic acid and...

 (DOC), are anionic detergents produced by the liver to aid in digestion and absorption of fats and oils.

Cationic detergents

Cationic detergents are similar to the anionic ones, with a hydrophobic component, but, instead of the anionic sulfonate group, the cationic surfactants have quaternary ammonium as the polar end. The ammonium center is positively charged.

Non-ionic and zwitterionic detergents

Non-ionic detergents are characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on polyoxyethylene or a glycoside
Glycoside
In chemistry, a glycoside is a molecule in which a sugar is bound to a non-carbohydrate moiety, usually a small organic molecule. Glycosides play numerous important roles in living organisms. Many plants store chemicals in the form of inactive glycosides. These can be activated by enzyme...

. Common examples of the former include Tween
Polysorbate
Polysorbates are a class of emulsifiers used in some pharmaceuticals and food preparation. They are often used in cosmetics to solubilize essential oils into water-based products. Polysorbates are oily liquids derived from PEG-ylated sorbitan esterified with fatty acids...

, Triton, and the Brij series. These materials are also known as ethoxylates or PEGylates). 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
CHAPS detergent
CHAPS is a zwitterionic detergent used in the laboratory to solubilize biological macromolecules such as proteins. It is used as a non-denaturing solvent in the process of protein purification and is especially useful in purifying membrane proteins, which are often sparingly soluble or insoluble in...

.

See surfactants for more applications.

Laundry detergents

One of the largest applications of detergents is for cleaning clothing. The formulations are complex, reflecting the diverse demands of the application and the highly competitive consumer market. In general, laundry detergents contain water softeners, surfactants, bleach, enzymes, brighteners, fragrances, and many other agents. The formulation is strongly affected by the temperature of the cleaning water and varies from country to country.

Fuel additives

Both carburetors and fuel injector components of Otto engine
Otto engine
-Otto Engine Types:There are three types of internal combustion engines designed by German inventors Nikolaus August Otto and his partner Eugen Langen. They are the 1862 compression engine, which failed, the 1864 atmospheric engine, and the engine known today as the "Gasoline Engine", the Otto...

s 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.

Soapless soap

Soapless soap refers to a soapfree
Soap substitute
A soap substitute refers to detergents or cleansing creams, other than soap, for cleaning the skin, especially removing greasy films or glandular exudates. Soap substitutes can be made from a variety of sources including plants with high saponin levels...

 liquid
Hydrophile
A hydrophile, from the Greek "water" and φιλια "love," is a molecule or other molecular entity that is attracted to, and tends to be dissolved by water. A hydrophilic molecule or portion of a molecule is one that has a tendency to interact with or be dissolved by, water and other polar substances...

 cleanser
Cleanser
A cleanser is a product used to cleanse something, such as a detergent or industrial cleaning agent.A popular type of cleanser is a facial care product that is used to remove make-up, dead skin cells, oil, dirt, and other types of pollutants from the skin of the face...

 with a slightly acidic pH
PH
In chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Pure water is said to be neutral, with a pH close to 7.0 at . Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline...

. Soapless soaps are used in an array of products.

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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