Quaternary ammonium cation
Encyclopedia
Quaternary
ammonium cations, also known as quats, are positively charged polyatomic ion
s of the structure NR4+, R being an alkyl group or an aryl
group. Unlike the ammonium ion
(NH4+) and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the pH
of their solution. Quaternary ammonium salts or quaternary ammonium compounds (called quaternary amines in oilfield parlance) are salts of quaternary ammonium cations with an anion.
of tertiary amines, in a process called quaternization. Typically one of the alkyl groups on the amine is larger than the others. A typical synthesis is for benzalkonium chloride
from a long-chain alkyldimethylamine and benzyl chloride
:
s, and as antistatic agent
s (e.g. in shampoo
s). In liquid
fabric softeners, the chloride
salts are often used. In dryer
anticling
strips, the sulfate
salts are often used. Spermicidal jellies also contain quaternary ammonium salts.
s and disinfectants. Examples are benzalkonium chloride
, benzethonium chloride
, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride
, cetrimonium
, cetrimide, dofanium chloride, tetraethylammonium bromide
, didecyldimethylammonium chloride
and domiphen bromide. Also good against fungi, amoeba, and enveloped viruses, quats act by disrupting the cell membrane. Quaternary ammonium compounds are lethal to a wide variety of organisms except endospores, Mycobacterium tuberculosis
, non-enveloped viruses, and Pseudomonas spp.
In contrast to phenolics, quaternary ammonium compounds are not very effective in the presence of organic compounds. Yet, they are very effective in combination with phenols. Quaternary ammonium compounds are deactivated by soaps, other anionic detergents, and cotton fibers. Also, they are not recommended for use in hard water. Effective levels are at 200 ppm. They are effective at temperatures up to 212 °F (100 °C).
Along with sodium hypochlorite, quaternary ammonium salts are the primary chemicals used in foodservice
industry as sanitizing agents.
s (PTC). Such catalysts accelerate reactions between reagents dissolved in immiscible solvents. The highly reactive reagent dichlorocarbene
is generated via PTC by reaction of chloroform and sodium hydroxide.
s, specifically glycine betaine, which stabilize osmotic pressure in cells.
They are thought to be the chemical group responsible for anaphylactic reactions that occur with use of neuromuscular blocking drugs during general anaesthesia
in surgery
. Quaternium-15
is the single most often found cause of allergic contact dermatitis
of the hands (16.5% in 959 cases)
Quaternary compound
In chemistry, a quaternary compound is a cation consisting of a central positively charged nitrogen group atom with four substituents, especially organic groups, discounting hydrogen atoms....
ammonium cations, also known as quats, are positively charged polyatomic ion
Polyatomic ion
A polyatomic ion, also known as a molecular ion, is a charged species composed of two or more atoms covalently bonded or of a metal complex that can be considered as acting as a single unit in the context of acid and base chemistry or in the formation of salts. The prefix "poly-" means "many," in...
s of the structure NR4+, R being an alkyl group or an aryl
Aryl
In the context of organic molecules, aryl refers to any functional group or substituent derived from an aromatic ring, be it phenyl, naphthyl, thienyl, indolyl, etc....
group. Unlike the ammonium ion
Ammonium
The ammonium cation is a positively charged polyatomic cation with the chemical formula NH. It is formed by the protonation of ammonia...
(NH4+) and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the 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...
of their solution. Quaternary ammonium salts or quaternary ammonium compounds (called quaternary amines in oilfield parlance) are salts of quaternary ammonium cations with an anion.
Synthesis
Quaternary ammonium compounds are prepared by alkylationAlkylation
Alkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene . Alkylating agents are widely used in chemistry because the alkyl group is probably the most common group encountered in...
of tertiary amines, in a process called quaternization. Typically one of the alkyl groups on the amine is larger than the others. A typical synthesis is for benzalkonium chloride
Benzalkonium chloride
Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. This product is a nitrogenous cationic surface-acting agent belonging to the quaternary ammonium group...
from a long-chain alkyldimethylamine and benzyl chloride
Benzyl chloride
Benzyl chloride, or α-chlorotoluene, is an organic compound with the formula C6H5CH2Cl. This colourless liquid is a reactive organochlorine compound that is a widely used chemical building block.-Preparation:...
:
- CH3(CH2)nN(CH3)2 + ClCH2C6H5 → CH3(CH2)nN(CH3)2CH2C6H5]+Cl-
Applications
Quaternary ammonium salts are used as disinfectants, surfactants, fabric softenerFabric softener
Fabric softener is used to prevent static cling and make fabric softer. It is available as a liquid, crystals and dryer sheets.- Varieties :...
s, and as antistatic agent
Antistatic agent
An antistatic agent is a compound used for treatment of materials or their surfaces in order to reduce or eliminate buildup of static electricity generally caused by the triboelectric effect. Its role is to make the surface or the material itself slightly conductive, either by being conductive...
s (e.g. in shampoo
Shampoo
Shampoo is a hair care product used for the removal of oils, dirt, skin particles, dandruff, environmental pollutants and other contaminant particles that gradually build up in hair...
s). In liquid
Liquid
Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...
fabric softeners, the chloride
Chloride
The chloride ion is formed when the element chlorine, a halogen, picks up one electron to form an anion Cl−. The salts of hydrochloric acid HCl contain chloride ions and can also be called chlorides. The chloride ion, and its salts such as sodium chloride, are very soluble in water...
salts are often used. In dryer
Clothes dryer
A clothes dryer or tumble dryer is a household appliance that is used to remove moisture from a load of clothing and other textiles, generally shortly after they are cleaned in a washing machine....
anticling
Fabric softener
Fabric softener is used to prevent static cling and make fabric softer. It is available as a liquid, crystals and dryer sheets.- Varieties :...
strips, the sulfate
Sulfate
In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...
salts are often used. Spermicidal jellies also contain quaternary ammonium salts.
As antimicrobials
Quaternary ammonium compounds have also been shown to have antimicrobial activity. Certain quaternary ammonium compounds, especially those containing long alkyl chains, are used as antimicrobialAntimicrobial
An anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes or prevent the growth of microbes...
s and disinfectants. Examples are benzalkonium chloride
Benzalkonium chloride
Benzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. This product is a nitrogenous cationic surface-acting agent belonging to the quaternary ammonium group...
, benzethonium chloride
Benzethonium chloride
Benzethonium chloride is a synthetic quaternary ammonium salt. This compound is an odorless white solid; soluble in water. It has surfactant, antiseptic, and anti-infective properties, and it is used as a topical antimicrobial agent in first aid antiseptics. It is also found in cosmetics and...
, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chloride
Cetylpyridinium chloride
Cetylpyridinium chloride is a cationic quaternary ammonium compound in some types of mouthwashes, toothpastes, lozenges, throat sprays, breath sprays, and nasal sprays. It is an antiseptic that kills bacteria and other microorganisms. It has been shown to be effective in preventing dental plaque...
, cetrimonium
Cetrimonium
Cetrimonium, cetyl trimethylammonium, or hexadecyltrimethylammonium is a quaternary ammonium cation whose salts are used as antiseptics:* Cetrimonium bromide * Cetrimonium chloride...
, cetrimide, dofanium chloride, tetraethylammonium bromide
Tetraethylammonium bromide
Tetraethylammonium bromide is a quaternary ammonium salt. It is a common source for the tetraethylammonium cation. Currently, no NFPA 704 for TEABr has been established. Industrially, it can be used to determine the epoxide value of various adhesives....
, didecyldimethylammonium chloride
Didecyldimethylammonium chloride
Didecyldimethylammonium chloride is an antiseptic/disinfectant, which is used in many biocidal applications. They cause disruption of intermolecular interactions and dissociation of lipid bilayers. They are Broad spectrum Bactericidal and Fungicidal.They can be used as Disinfectant Cleaner for...
and domiphen bromide. Also good against fungi, amoeba, and enveloped viruses, quats act by disrupting the cell membrane. Quaternary ammonium compounds are lethal to a wide variety of organisms except endospores, Mycobacterium tuberculosis
Mycobacterium tuberculosis
Mycobacterium tuberculosis is a pathogenic bacterial species in the genus Mycobacterium and the causative agent of most cases of tuberculosis . First discovered in 1882 by Robert Koch, M...
, non-enveloped viruses, and Pseudomonas spp.
In contrast to phenolics, quaternary ammonium compounds are not very effective in the presence of organic compounds. Yet, they are very effective in combination with phenols. Quaternary ammonium compounds are deactivated by soaps, other anionic detergents, and cotton fibers. Also, they are not recommended for use in hard water. Effective levels are at 200 ppm. They are effective at temperatures up to 212 °F (100 °C).
Along with sodium hypochlorite, quaternary ammonium salts are the primary chemicals used in foodservice
Foodservice
Food Service or catering industry defines those businesses, institutions, and companies responsible for any meal prepared outside the home...
industry as sanitizing agents.
As phase transfer catalysts
In organic synthesis, quaternary ammonium salts are employed as phase transfer catalystPhase transfer catalyst
In chemistry, a phase transfer catalyst or PTC is a catalyst that facilitates the migration of a reactant from one phase into another phase where reaction occurs. Phase transfer catalysis is a special form of heterogeneous catalysis. Ionic reactants are often soluble in an aqueous phase but...
s (PTC). Such catalysts accelerate reactions between reagents dissolved in immiscible solvents. The highly reactive reagent dichlorocarbene
Dichlorocarbene
Dichlorocarbene is a carbene commonly encountered in organic chemistry. This reactive intermediate with chemical formula CCl2 is easily available by reaction of chloroform and a base such as potassium t-butoxide or sodium hydroxide dissolved in water...
is generated via PTC by reaction of chloroform and sodium hydroxide.
Osmolytes
Quaternary ammonium compounds are present in osmolyteOsmolyte
Osmolytes are compounds affecting osmosis. They are soluble in the solution within a cell, or in the surrounding fluid, e.g. as plasma osmolytes. They play a role in maintaining cell volume and fluid balance. For example, when a cell swells due to external osmotic pressure, membrane channels open...
s, specifically glycine betaine, which stabilize osmotic pressure in cells.
Health effects
Quaternary ammonium compounds can display a range of health effects, amongst which are mild skin and respiratory irritation up to severe caustic burns on skin and gastro-intestinal lining (depending on concentration), gastro-intestinal symptoms (e.g., nausea and vomiting), coma, convulsions, hypotension and death.They are thought to be the chemical group responsible for anaphylactic reactions that occur with use of neuromuscular blocking drugs during general anaesthesia
General anaesthesia
General anaesthesia is a state of unconsciousness and loss of protective reflexes resulting from the administration of one or more general anaesthetic agents...
in surgery
Surgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
. Quaternium-15
Quaternium-15
Quaternium-15 is a quaternary ammonium salt used as a preservative in many cosmetics and industrial substances. It acts as a formaldehyde releaser...
is the single most often found cause of allergic contact dermatitis
Contact dermatitis
Contact dermatitis is a term for a skin reaction resulting from exposure to allergens or irritants . Phototoxic dermatitis occurs when the allergen or irritant is activated by sunlight....
of the hands (16.5% in 959 cases)
See also
- Benzalkonium chlorideBenzalkonium chlorideBenzalkonium chloride, also known as alkyldimethylbenzylammonium chloride and ADBAC, is a mixture of alkylbenzyldimethylammonium chlorides of various even-numbered alkyl chain lengths. This product is a nitrogenous cationic surface-acting agent belonging to the quaternary ammonium group...
, benzethonium chlorideBenzethonium chlorideBenzethonium chloride is a synthetic quaternary ammonium salt. This compound is an odorless white solid; soluble in water. It has surfactant, antiseptic, and anti-infective properties, and it is used as a topical antimicrobial agent in first aid antiseptics. It is also found in cosmetics and...
, methylbenzethonium chloride, cetalkonium chloride, cetylpyridinium chlorideCetylpyridinium chlorideCetylpyridinium chloride is a cationic quaternary ammonium compound in some types of mouthwashes, toothpastes, lozenges, throat sprays, breath sprays, and nasal sprays. It is an antiseptic that kills bacteria and other microorganisms. It has been shown to be effective in preventing dental plaque...
, cetrimoniumCetrimoniumCetrimonium, cetyl trimethylammonium, or hexadecyltrimethylammonium is a quaternary ammonium cation whose salts are used as antiseptics:* Cetrimonium bromide * Cetrimonium chloride...
, cetrimide, dofanium chloride, tetraethylammonium bromideTetraethylammonium bromideTetraethylammonium bromide is a quaternary ammonium salt. It is a common source for the tetraethylammonium cation. Currently, no NFPA 704 for TEABr has been established. Industrially, it can be used to determine the epoxide value of various adhesives....
, and domiphen bromide – antimicrobialAntimicrobialAn anti-microbial is a substance that kills or inhibits the growth of microorganisms such as bacteria, fungi, or protozoans. Antimicrobial drugs either kill microbes or prevent the growth of microbes...
ingredients found in various over-the-counter products - CarnitineCarnitineCarnitine is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine. In living cells, it is required for the transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids for the generation of metabolic energy. It is widely...
- Cetyl trimethylammonium bromide (CTAB), stearalkonium chlorideStearalkonium chlorideStearalkonium chloride is a type of benzalkonium chloride which is used as an anti-static agent, a surfactant and an antimicrobial. It is an ingredient in some cosmetics and hair care products, particularly conditioners....
– cationic surfactantSurfactantSurfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
s commonly used in toiletries - CholineCholineCholine is a water-soluble essential nutrient. It is usually grouped within the B-complex vitamins. Choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation....
- Cocamidopropyl betaineCocamidopropyl betaineCocamidopropyl betaine is a synthetic surfactant derived from coconut oil and dimethylaminopropylamine. It is a zwitterionic chemical compound with a quaternary ammonium cation...
(CAPB), a common Zwitterionic surfactantSurfactantSurfactants are compounds that lower the surface tension of a liquid, the interfacial tension between two liquids, or that between a liquid and a solid...
used ubiquitously in toiletries - DenatoniumDenatoniumDenatonium, usually available as denatonium benzoate and as denatonium saccharide, is the bitterest chemical compound known; with bitterness thresholds of 0.05 ppm for the benzoate and 0.01 ppm for the saccharide.It was discovered in 1958 during research on local anesthetics by Macfarlan...
, the most bitter compound known - Dimethyldioctadecylammonium chloride
- ParaquatParaquatParaquat is the trade name for N,N′-dimethyl-4,4′-bipyridinium dichloride, one of the most widely used herbicides in the world. Paraquat, a viologen, is quick-acting and non-selective, killing green plant tissue on contact. It is also toxic to human beings and animals...
, an herbicide - PolyquaterniumPolyquaterniumPolyquaternium is the International Nomenclature for Cosmetic Ingredients designation for several polycationic polymers that are used in the personal care industry. Polyquaternium is a neologism used to emphasize the presence of quaternary ammonium centers in the polymer. INCI has approved at...
, designations for quaternary ammonium-containing polymers used for personal care products - Quaternary ammonium muscle relaxants
- Tetra-n-butylammonium bromideTetra-n-butylammonium bromideTetra-n-butylammonium bromide is a quaternary ammonium salt with a bromine counterion commonly used as a phase transfer catalyst.-See also:*Tetrabutylammonium tribromide, with an additional Br2 unit*Tetrabutylammonium fluoride...
and Aliquat 336Aliquat 336Aliquat 336 is a mixture of C8 and C10 chains with C8 predominating. It is a quaternary ammonium salt used as a phase transfer catalyst and metal extraction reagent.-Applications:...
, common phase transfer catalystPhase transfer catalystIn chemistry, a phase transfer catalyst or PTC is a catalyst that facilitates the migration of a reactant from one phase into another phase where reaction occurs. Phase transfer catalysis is a special form of heterogeneous catalysis. Ionic reactants are often soluble in an aqueous phase but...
s - Tetramethylammonium chlorideTetramethylammonium chlorideTetramethylammonium chloride is a quaternary ammonium salt with the chemical formula [4N]Cl. It is a very hygroscopic colourless solid that is soluble in water and polar organic solvents...
- Tetramethylammonium hydroxideTetramethylammonium hydroxideTetramethylammonium hydroxide is a quaternary ammonium salt with the molecular formula 4NOH. It is used as an anisotropic etchant of silicon. It is also used as a basic solvent in the development of acidic photoresist in the photolithography process. Since it is a phase transfer catalyst, it is...