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A detergent is a
surfactant Surfactants are compounds that lower the (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as s, agents, , s, or s. The word "surfactant" is a of ''surface-active a ...

surfactant
or a
mixture In chemistry, a mixture is a material made up of two or more different chemical substances which are not chemically combined. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in th ...

mixture
of surfactants with cleansing properties when in
dilute
dilute
solutions Image:SaltInWaterSolutionLiquid.jpg, Making a saline water solution by dissolving Salt, table salt (sodium chloride, NaCl) in water. The salt is the solute and the water the solvent. In chemistry, a solution is a special type of Homogeneous and ...
. There are a large variety of detergents; often they are the sodium salts of long chain alkyl hydrogen sulphate or a long chain of benzene sulphonic acid. The most commonly found detergents are alkylbenzene sulfonates: a family of
soap Soap is a salt (chemistry), salt of a fatty acid used in a variety of cleansing and lubricating products. In a domestic setting, soaps are surfactants usually used for washing, bathing, and other types of housekeeping. In industrial settings, ...

soap
-like compounds that are more soluble in
hard water Hard water is water Water (chemical formula H2O) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living orga ...
, because the polar
sulfonate 144px, The sulfonate ion. A sulfonate is a salt Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of Salt (chemistry), salts; salt in its natural form as a crystallinity, crystal ...

sulfonate
(of detergents) is less likely than the polar
carboxylate A carboxylate is the conjugate base of a carboxylic acid. Carboxylate salts are salt (chemistry), salts that have the general formula M(RCOO)''n'', where M is a metal and ''n'' is 1, 2,...; ''carboxylate esters'' have the general formula R ...

carboxylate
(of soap) to bind to calcium and other ions found in hard water.


Definitions

The word ''detergent'' is derived from the Latin adjective ''detergens'', from the verb ''detergere'', meaning to wipe or polish off. Detergent is a
surfactant Surfactants are compounds that lower the (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfactants may act as s, agents, , s, or s. The word "surfactant" is a of ''surface-active a ...

surfactant
or a
mixture In chemistry, a mixture is a material made up of two or more different chemical substances which are not chemically combined. A mixture is the physical combination of two or more substances in which the identities are retained and are mixed in th ...

mixture
of surfactants with cleansing properties when in
solutions Image:SaltInWaterSolutionLiquid.jpg, Making a saline water solution by dissolving Salt, table salt (sodium chloride, NaCl) in water. The salt is the solute and the water the solvent. In chemistry, a solution is a special type of Homogeneous and ...
. However, conventionally, detergent is used to mean synthetic cleaning compounds as opposed to ''soap'' (a salt of the natural
fatty acid In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during ...
), even though soap is also a detergent in the true sense. In domestic contexts, the term ''detergent'' refers to household cleaning products such as ''
laundry detergent Laundry detergent is a type of detergent A detergent is a surfactant Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Sur ...
'' or '' dish detergent'', which are in fact complex mixture of different compounds, not all of which are by themselves detergents. Detergency is the ability to remove unwanted substances termed 'soils' from a substrate (e.g clothing).


Structure and properties

Detergents are a group of compounds with an amphiphilic structure, where each molecule has a hydrophilic (polar) head and a long hydrophobic (non-polar) tail. The hydrophobic portion of these molecules may be straight- or branched-chain
hydrocarbon In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, prop ...
s, or it may have a
steroid A steroid is a biologically active organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), millions of organic compounds are known. The study of the prope ...

steroid
structure. The hydrophilic portion is more varied, they may be ionic or non-ionic, and can range from a simple or a relatively elaborate structure. Detergents are surfactants since they can decrease the surface tension of water. Their dual nature facilitates the mixture of hydrophobic compounds (like oil and grease) with water. Because air is not hydrophilic, detergents are also
foaming agentA foaming agent is a material that facilitates the formation of foam foam bubbles Foam is an object formed by trapping pockets of gas in a liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that contin ...
s to varying degrees. Detergent molecules aggregate to form
micelle Image:Micelle scheme-en.svg, 250px, Scheme of a micelle formed by phospholipids in an aqueous solution A micelle () or micella () (plural micelles or micellae, respectively) is an aggregate (or supramolecular assembly) of surfactant phospholipid ...

micelle
s, which makes them soluble in water. The hydrophobic group of the detergent is the main driving force of micelle formation, its aggregation forms the hydrophobic core of the micelles. The micelle can remove grease, protein or soiling particles. The concentration at which micelles start to form is the critical micelle concentration (CMC), and the temperature at which the micelles further aggregate to separate the solution into two phases is the cloud point when the solution becomes cloudy and detergency is optimal. Detergents work better in an alkaline pH. The properties of detergents are dependent on the molecular structure of the
monomer In chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, properties, behavior and the changes they undergo during a ...

monomer
. The ability to foam may be determined by the head group, for example anionic surfactants are high-foaming, while nonionic surfactants may be non-foaming or low-foaming.


Chemical classifications of detergents

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


Anionic detergents

Typical anionic detergents are
alkylbenzene sulfonates Alkylbenzene sulfonates are a class of anionic surfactants, consisting of a hydrophilic sulfonate head-group and a hydrophobic alkylbenzene tail-group. Along with sodium laureth sulfate they are one of the oldest and most widely used synthetic dete ...

alkylbenzene sulfonates
. The
alkylbenzeneThe alkylbenzenes are derivatives of benzene Benzene is an organic chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than ...
portion of these
anions An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objects that can be touched are ...

anions
is lipophilic and the sulfonate is hydrophilic. Two varieties have been popularized, those with branched
alkyl group In organic chemistry, an alkyl substituent A substituent is one or a group of atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space ...
s and those with linear alkyl groups. The former were largely phased out in economically advanced societies because they are poorly biodegradable.Eduard Smulders, Wolfgang Rybinski, Eric Sung, Wilfried Rähse, Josef Steber, Frederike Wiebel, Anette Nordskog, "Laundry Detergents" in Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. Anionic detergents are the most common form of detergents, and an estimated 6 billion kilograms of anionic detergents are produced annually for the domestic markets.
Bile acid Bile acids are steroid acids found predominantly in the bile of mammals and other vertebrates. Diverse bile acids are synthesized in the liver. Bile acids are conjugated with taurine or glycine residues to give anions called bile salts. Primary bi ...
s, such as
deoxycholic acid Deoxycholic acid ( conjugate base deoxycholate), also known as cholanoic acid, Kybella, Celluform Plus, Belkyra, and 3α,12α-dihydroxy-5β-cholan-24-oic acid, is a bile acid Bile acids are steroid acid An acid is a molecule or ion capable ...

deoxycholic acid
(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 anionic ones, but
quaternary ammonium Quaternary ammonium cations, also known as quats, are positively charged polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalently bonded set of two or more atoms, or of a metal complex, that can be considered to behave ...
replaces the hydrophilic anionic sulfonate group. The ammonium sulfate center is positively charged. Cationic surfactants generally have poor detergency.


Non-ionic detergents

Non-ionic detergents are characterized by their uncharged, hydrophilic headgroups. Typical non-ionic detergents are based on
polyoxyethylene Polyethylene glycol (PEG; ) is a polyether compound derived from petroleum with many applications, from industrial manufacturing to medicine. PEG is also known as polyethylene oxide (PEO) or polyoxyethylene (POE), depending on its molecular wei ...
or a
glycoside In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science that covers the Chemical element, elements that make up matter to the chemical compound, compounds composed of atoms ...

glycoside
. Common examples of the former include
Tween Preadolescence, also known as pre-teen or tween, is a stage of Human development (biology), human development following early childhood and preceding adolescence.New Oxford American Dictionary. 2nd Edition. 2005. Oxford University Press. It comm ...
,
Triton Triton commonly refers to: * Triton (mythology), a Greek god * Triton (moon), a satellite of Neptune Triton may also refer to: Biology * Triton cockatoo, a parrot * Triton (gastropod), a group of sea snails * ''Triton'', a synonym of ''Triturus'', ...

Triton
, and the Brij series. These materials are also known as ethoxylates or PEGylates and their metabolites,
nonylphenol Nonylphenols are a family of closely related organic compounds composed of phenol bearing a 9 carbon-tail. Nonylphenols can come in numerous structures, all of which may be considered alkylphenols. They are used in manufacturing antioxidants, lubr ...

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.


Amphoteric detergents

Amphoteric In chemistry, an amphoteric compound is a molecule or ion that can react both as an acid An acid is a molecule or ion An ion () is a particle In the Outline of physical science, physical sciences, a particle (or corpuscule in older ...
or zwitterionic detergents have
zwitterionIn chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds composed of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo ...
s within a particular pH range, and possess a net zero charge arising from the presence of equal numbers of +1 and −1 charged chemical groups. Examples include
CHAPS The Clearing House Automated Payment System (CHAPS) is real-time gross settlement Real-time gross settlement (RTGS) systems are specialist Electronic funds transfer, funds transfer systems where the transfer of money or securities takes place from ...
.


History

Soap is known to be have been used as a surfactant for washing clothes since the time in 2,500 B.C. In
ancient Egypt Ancient Egypt was a civilization  A civilization (or civilisation) is a that is characterized by , , a form of government, and systems of communication (such as ). Civilizations are intimately associated with additional char ...

ancient Egypt
, was used as a wash additive. In the 19th century, synthetic surfactants began to be created, for example from olive oil.
Sodium silicate Sodium silicate is a generic name for chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from more than one chemical element, element ...

Sodium silicate
(water glass) was used in soap-making in the United States in the 1860s, and in 1876,
Henkel Henkel AG & Co. KGaA is a German chemical and consumer goods company headquartered in Düsseldorf Düsseldorf ( , , ; often in English sources; Low Franconian Low Franconian, Low Frankish, NetherlandicSarah Grey Thomason, Terrence Ka ...

Henkel
sold a sodium silicate-based product that can be used with soap and marketed as a "universal detergent" (''Universalwaschmittel'') in Germany. Soda was then mixed with sodium silicate to produce Germany's first brand name detergent Bleichsoda. In 1907 Henkel also added a bleaching agent
sodium perborate Sodium perborate is chemical compound A chemical compound is a chemical substance A chemical substance is a form of matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having ...

sodium perborate
to launch the first 'self-acting' laundry detergent
Persil Persil is a German brand of laundry detergent Laundry detergent, or washing powder, is a type of detergent (cleaning agent) used for cleaning laundry. Laundry detergent is manufactured in powder and liquid form. While powdered and liquid d ...

Persil
to eliminate the laborious rubbing of laundry by hand. During the
First World War World War I, often abbreviated as WWI or WW1, also known as the First World War or the Great War, was a global war A world war is "a war War is an intense armed conflict between states State may refer to: Arts, entertainmen ...

First World War
, there was a shortage of oils and fats needed to make soap. In order find alternatives for soap, synthetic detergents were made in Germany by chemists using raw material derived from coal tar. These early products, however, did not provide sufficient detergency. In 1928, effective detergent was made through the
sulfation Sulfation or sulfurylation in biochemistry is the enzyme-catalyzed Conjugation (biochemistry), conjugation of a Sulfonic acid, sulfo group (not a sulfate or sulfuryl group) to another molecule. This biotransformation involves a sulfotransferase e ...
of
fatty alcohol Fatty alcohols (or long-chain alcohols In chemistry, alcohol is an organic compound that carries at least one hydroxyl functional group (−OH) bound to a Saturated and unsaturated compounds, saturated carbon atom. The term alcohol origina ...
, but large-scale production was not feasible until low-cost fatty alcohols become available in the early 1930s. The synthetic detergent created was more effective and less likely to form scum than soap in hard water, and can also eliminate acid and alkaline reactions and decompose dirt. Commercial detergent products with fatty alcohol sulphates began to be sold, initially in 1932 in Germany by
Henkel Henkel AG & Co. KGaA is a German chemical and consumer goods company headquartered in Düsseldorf Düsseldorf ( , , ; often in English sources; Low Franconian Low Franconian, Low Frankish, NetherlandicSarah Grey Thomason, Terrence Ka ...

Henkel
. In the United States, detergents were sold in 1933 by
Procter & Gamble The Procter & Gamble Company (P&G) is an American multinational consumer goods A final good or consumer good is a final product In Production (economics), production, a final product, or finished product is a product (business), product th ...
(
Dreft Dreft is a laundry detergent Laundry detergent is a type of detergent A detergent is a surfactant or a mixture of surfactants with cleansing properties in dilute solutions. These substances are usually alkylbenzene sulfonates, a family o ...

Dreft
) primarily in areas with hard water. However, sales in the US grew slowly until the introduction of 'built' detergents with the addition of effective phosphate builder developed in the early 1940s. The builder improves the performance of the surfactants by softening the water through the
chelation Chelation is a type of bonding of ions An ion () is an atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All ...
of calcium and magnesium ions, helping to maintain an alkaline pH, as well as dispersing and keeping the soiling particles in solution. The development of the petrochemical industry after the Second World War also yielded material for the production of a range of synthetic surfactants, and alkylbenzene sulfonates became the most important detergent surfactants used. By the 1950s,
laundry detergent Laundry detergent is a type of detergent A detergent is a surfactant Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Sur ...
s had become widespread, and largely replaced soap for cleaning clothes in developed countries. Over the years, many types of detergents have been developed for a variety of purposes, for example, low-sudsing detergents for use in front-loading washing machines, heavy-duty detergents effective in removing grease and dirt, all-purpose detergents and specialty detergents. They become incorporated in various products outside of laundry use, for example in
dishwasher detergent Dishwasher detergent is a detergent made for washing dishes in a dishwasher. Dishwasher detergent is different from dishwashing liquid made to wash dishes by hand. Uses When using a dishwasher, the user must select a special detergent for its use. ...
s, shampoo, toothpaste, industrial cleaners, and in lubricants and fuels to reduce or prevent the formation of sludge or deposits. The formulation of detergent products may include
bleach Bleach is the generic name for any chemical product that is used industrially and domestically to remove color from a fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers, specifically, to a dilute so ...

bleach
, fragrances, dyes and other additives. The use of
phosphates in detergentPhosphates in detergent refers to the use of phosphates as an ingredient in a detergent product. The advantage of using phosphates in a consumer laundry detergent or dishwashing detergent is that they make detergents more efficient by chelation, chel ...
, however, led to concerns over
nutrient pollution Nutrient pollution, a form of water pollution Water pollution (or aquatic pollution) is the contamination of water bodies ( Lysefjord) in Norway Norway ( nb, ; nn, ; se, Norga; smj, Vuodna; sma, Nöörje), officially the Ki ...
and demand for changes to the formulation of the detergents. Concerns were also raised over the use of surfactants such as branched alkylbenzene sulfonate (tetrapropylenebenzene sulfonate) that lingers in the environment, which led to their replacement by surfactants that are more biodegradable, such as linear alkylbenzene sulfonate. Developments over the years have included the use of
enzymes Enzymes () are proteins that act as biological catalysts (biocatalysts). Catalysts accelerate chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates int ...
, substitutes for phosphates such as
zeolite Zeolites are microporous, aluminosilicate Aluminosilicate mineral In geology Geology (from the Ancient Greek γῆ, ''gē'' ("earth") and -λoγία, ''-logia'', ("study of", "discourse")) is an Earth science concerned with the solid Ear ...

zeolite
A and NTA, as
bleach activator Bleach activators are compounds that allow a lower washing temperature than would be required otherwise to achieve the full activity of bleaching agents in the wash liquor. Bleaching agents, usually peroxides, are usually sufficiently active only ...
, sugar-based surfactants which are biodegradable and milder to skin, and other green friendly products, as well as changes to the form of delivery such as tablets, gels and pods.


Major applications of detergents


Household cleaning

One of the largest applications of detergents is for household and shop cleaning including dish washing and washing
laundry Laundry refers to the washing of clothing and other textiles, and, more broadly, their drying Drying is a process consisting of the removal of water or another by from a , or . This process is often used as a final production step before s ...

laundry
. These detergents are commonly available as powders or concentrated solutions, and the formulations of these detergents are often complex mixtures of a variety of chemicals aside from surfactants, reflecting the diverse demands of the application and the highly competitive consumer market. These detergents may contain the following components: * surfactants * foam regulators * builders * bleach * bleach activators * enzymes * dyes * fragrances * other additives


Fuel additives

Both carburetors and fuel injector components of
internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine In thermodynamics and engineering, a heat engine is a system that converts heat to mechanical energy, which can then be used to do work (physics), mechanical work. It doe ...

internal combustion engine
s benefit from detergents in the fuels to prevent
fouling Fouling is the accumulation of unwanted material on solid surfaces. The fouling materials can consist of either living organisms (biofouling) or a non-living substance (inorganic or organic). Fouling is usually distinguished from other surfa ...
. Concentrations are about 300 ppm. Typical detergents are long-chain
amine In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, ...

amine
s and
amide In organic chemistry Organic chemistry is a branch of chemistry Chemistry is the study of the properties and behavior of . It is a that covers the that make up matter to the composed of s, s and s: their composition, structure, ...

amide
s such as polyisobuteneamine and polyisobuteneamide/
succinimide Succinimide is an organic compound with the formula (CH2)2(CO)2NH. This white solid is used in a variety of organic syntheses, as well as in some industrial silver plating processes. The compound is classified as a cyclic imide. It may be prepared ...

succinimide
.


Biological reagent

Reagent grade detergents are employed for the isolation and purification of
integral membrane proteins An integral membrane protein (IMP) is a type of membrane protein Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Int ...
found in biological cells. Solubilization of
cell membrane The cell membrane (also known as the plasma membrane (PM) or cytoplasmic membrane, and historically referred to as the plasmalemma) is a biological membrane A biological membrane, biomembrane or cell membrane is a selectively permeable membra ...

cell membrane
bilayers requires a detergent that can enter the inner membrane
monolayerA monolayer is a single, closely packed layer of atom An atom is the smallest unit of ordinary matter In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. All everyday objec ...

monolayer
. Advancements in the purity and sophistication of detergents have facilitated structural and biophysical characterization of important membrane proteins such as
ion channels s (typically four per channel), 2 - outer vestibule, 3 - selectivity filter, 4 - diameter of selectivity filter, 5 - phosphorylation site, 6 - cell membrane. Ion channels are pore-forming membrane protein Membrane proteins are common proteins ...

ion channels
also the disrupt membrane by binding
lipopolysaccharide Lipopolysaccharides (LPS) are large molecule A molecule is an electrically Electricity is the set of physical phenomena associated with the presence and motion Image:Leaving Yongsan Station.jpg, 300px, Motion involves a change ...

lipopolysaccharide
, transporters, , and
photosystem II Photosystem II (or water-plastoquinone oxidoreductase) is the first protein complex in the light-dependent reactions of oxygenic photosynthesis. It is located in the thylakoid membrane of plants, algae, and cyanobacteria. Within the photosystem, ...

photosystem II
.


See also

* Cleavable detergent *
Dishwashing liquid Dishwashing liquid (BrE British English (BrE) is the standard dialect A standard language (also standard variety, standard dialect, and standard) is a language variety that has undergone substantial codification of grammar and usage an ...
*
DispersantA dispersant or a dispersing agent is a substance, typically a surfactant Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Surfac ...
*
Green cleaning Green cleaning refers to using cleaning methods and products with environmentally friendly Environment friendly processes, or environmental-friendly processes (also referred to as eco-friendly, nature-friendly, and green), are sustainability and ...
* Hard-surface cleaner *
Laundry detergent Laundry detergent is a type of detergent A detergent is a surfactant Surfactants are compounds that lower the surface tension (or interfacial tension) between two liquids, between a gas and a liquid, or between a liquid and a solid. Sur ...
*
List of cleaning products This is a list of cleaning products and agents. Cleaning agent Cleaning is the process of removing unwanted substances, such as dirt, infectious agents, and other impurities, from an object or environment. Cleaning occurs in many different contex ...
*
Triton X-100 Triton X-100 (''n'') is a nonionic surfactant that has a hydrophilic polyethylene oxide chain (on average it has 9.5 ethylene oxide units) and an aromatic hydrocarbon lipophilic or hydrophobic group. The hydrocarbon group is a 4-(2,2,4-Trimethylpen ...

Triton X-100


References


External links


About.com: How Do Detergents Clean


for detergents chemistry

an

related to laundry washing

an

{{Authority control Cleaning products Membrane-active molecules Surfactants