HOME

TheInfoList




Acetic acid , systematically named ethanoic acid , is a colourless liquid
organic compound 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 ...
with the
chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as parentheses, dashes, brackets, commas and ...
CH3COOH (also written as CH3CO2H, C2H4O2, or HC2H3O2).
Vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation; converting simple sugars to eth ...

Vinegar
is no less than 4% acetic acid by volume, making acetic acid the main component of vinegar apart from water. Acetic acid is the second simplest
carboxylic acid A carboxylic acid is an organic acid that contains a carboxyl group (C(=O)OH) attached to an R-group. The general formula of a carboxylic acid is R−COOH or R−CO2H, with substituent, R referring to the alkyl, alkenyl, aryl, or other group. ...
(after
formic acid Formic acid, systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH. It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. The word "formic" comes ...

formic acid
). It is an important
chemical reagent 200px, Reactants, such as sulfur (''pictured''), are the starting materials that are used in chemical reactions. A reagent is a substance or compound added to a system to cause a chemical reaction A chemical reaction is a process that leads ...
and industrial chemical, used primarily in the production of
cellulose acetate Cellulose acetate refers to any acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids ...

cellulose acetate
for
photographic film Photographic film is a strip or sheet of transparent film baseA film base is a transparent substrate which acts as a support medium for the photosensitive emulsion An emulsion is a mixture of two or more liquids that are normally Miscibil ...
,
polyvinyl acetate Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, white glue, carpenter's glue, school glue, or Elmer's glue in the US, is a widely available adhesive used for porous materials like wood, paper, and cloth. An a ...

polyvinyl acetate
for wood
glue adhesive dispensed from a tube Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that molecular binding , binds them together and resists their separati ...
, and synthetic fibres and fabrics. In households, diluted acetic acid is often used in
descaling agent A descaling agent or chemical descaler is a liquid 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 volume. All every ...
s. In the
food industry The food industry is a complex, global network of diverse businesses that supplies most of the food consumed by the World population, world's population. The term food industries covers a series of industrial activities directed at the producti ...
, acetic acid is controlled by the food additive code E260 as an
acidity regulator Acidity regulators, or pH control agents, are food additives used to change or maintain pH ( acidity or basicity). They can be organic or mineral acids, bases, neutralizing agents, or buffering agents. Typical agents include the following ...
and as a condiment. In
biochemistry Biochemistry or biological chemistry, is the study of chemical process In a scientific Science () is a systematic enterprise that Scientific method, builds and organizes knowledge in the form of Testability, testable explanations and pr ...

biochemistry
, the acetyl group, derived from acetic acid, is fundamental to all forms of life. When bound to
coenzyme A Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the Fatty acid metabolism#Synthesis, synthesis and Fatty acid metabolism#.CE.B2-Oxidation, oxidation of fatty acids, and the oxidation of pyruvic acid, pyruvate in the citric aci ...
, it is central to the
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities A bubble of exhaled gas in water In common usage and classical mechanics, a phys ...

metabolism
of
carbohydrate A carbohydrate () is a biomolecule , showing alpha helices, represented by ribbons. This poten was the first to have its suckture solved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendrew in 1958, for which they received a ...
s and
fat In nutrition Nutrition is the biochemical Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided ...

fat
s. The global demand for acetic acid is about 6.5 million
metric tons The tonne ( or ; symbol: t) is a metric unit of mass equal to 1,000 kilogram The kilogram (also kilogramme) is the base unit of mass Mass is the physical quantity, quantity of ''matter'' in a physical body. It is also a measu ...
per year (Mt/a), of which approximately 1.5 Mt/a is met by recycling; the remainder is manufactured from
methanol Methanol, also known as methyl alcohol, amongst other names, is a chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be se ...

methanol
. Vinegar is mostly dilute acetic acid, often produced by
fermentation Fermentation is a metabolism, metabolic process that produces chemical changes in organic Substrate (chemistry), substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in ...

fermentation
and subsequent oxidation of
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ (anatomy), ...

ethanol
.


Nomenclature

The
trivial name In chemistry, a trivial name is a nonsystematic name for a chemical substance. That is, the name is not recognized according to the rules of any formal system of chemical nomenclature such as IUPAC nomenclature of inorganic chemistry, IUPAC inorg ...
''acetic acid'' is the most commonly used and
preferred IUPAC name In chemical nomenclatureA chemical nomenclature is a set of rules to generate systematic names for chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) c ...
. The systematic name ''ethanoic acid'', a valid
IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the authoritative power over chemist ...
name, is constructed according to the substitutive nomenclature.IUPAC Provisional Recommendations 200
Chapter P-12.1; page 4
/ref> The name ''acetic acid'' derives from ''acetum'', the
Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the Roman Republic, it became ...

Latin
word for
vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation; converting simple sugars to eth ...

vinegar
, and is related to the word
acid An acid is a or capable of donating a (hydrogen ion H+) (a ), or, alternatively, capable of forming a with an (a ). The first category of acids are the proton donors, or s. In the special case of , proton donors form the H3O+ and are ...
itself. ''Glacial acetic acid'' is a name for water-free (
anhydrous A substance is anhydrous if it contains no 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 flui ...
) acetic acid. Similar to the
German German(s) may refer to: Common uses * of or related to Germany * Germans, Germanic ethnic group, citizens of Germany or people of German ancestry * For citizens of Germany, see also German nationality law * German language The German la ...

German
name ''Eisessig'' (''ice vinegar''), the name comes from the ice-like crystals that form slightly below room temperature at (the presence of 0.1% water lowers its melting point by 0.2 °C). A common
symbol A symbol is a mark, sign, or word In linguistics, a word of a spoken language can be defined as the smallest sequence of phonemes that can be uttered in isolation with semantic, objective or pragmatics, practical meaning (linguistics), m ...
for acetic acid is ''AcOH'', where ''Ac'' is the pseudoelement symbol representing the
acetyl In organic chemistry Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemis ...

acetyl
group A group is a number A number is a mathematical object used to counting, count, measurement, measure, and nominal number, label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with ...
−C(=O)−; the
conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory The Brønsted–Lowry theory (also called proton theory of acids and bases) is an acid–base reaction An acid–base reaction is a chemical reaction A chemical reactio ...
,
acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids) in the periodic table: Metalloids are i ...

acetate
(), is thus represented as ''AcO''. (The ''Ac'' is not to be confused with the symbol for the element
actinium Actinium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical eleme ...

actinium
; the context prevents confusion among organic chemists). To better reflect its structure, acetic acid is often written as –C(O)OH, −C(=O)OH, COOH, and . In the context of
acid–base reaction An acid–base reaction is a chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic transformations, chemical transformation of one set of chemical substances to another. Classically, chemical react ...
s, the abbreviation ''HAc'' is sometimes used, where ''Ac'' in this case is a symbol for acetate (rather than acetyl). Acetate is the
ion 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 ...
resulting from loss of from acetic acid. The name ''acetate'' can also refer to a
salt Salt is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure fo ...
containing this anion, or an
ester An ester is a derived from an (organic or inorganic) in which at least one –OH group is replaced by an –O– () group, as in the substitution reaction of a and an . s are s of ; they are important in biology, being one of the main classe ...

ester
of acetic acid.


Properties


Acidity

The hydrogen centre in the
carboxyl group A carboxylic acid is an organic acid that contains a carboxyl group (C(=O)OH) attached to an R-group. The general formula of a carboxylic acid is R−COOH or R−CO2H, with substituent, R referring to the alkyl, alkenyl, aryl, or other group. ...

carboxyl group
(−COOH) in carboxylic acids such as acetic acid can separate from the molecule by ionization: :CH3COOH CH3CO2 + H+ Because of this release of the
proton A proton is a subatomic particle, symbol or , with a positive electric charge of +1''e'' elementary charge and a mass slightly less than that of a neutron. Protons and neutrons, each with masses of approximately one atomic mass unit, are collecti ...

proton
(H+), acetic acid has acidic character. Acetic acid is a weak
monoprotic acid An acid is a molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically neutral group of two or more atoms ...
. In aqueous solution, it has a pKa value of 4.76. Its
conjugate base A conjugate acid, within the Brønsted–Lowry acid–base theory The Brønsted–Lowry theory (also called proton theory of acids and bases) is an acid–base reaction An acid–base reaction is a chemical reaction A chemical reactio ...
is
acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids) in the periodic table: Metalloids are i ...

acetate
(CH3COO). A 1.0  M solution (about the concentration of domestic vinegar) has a of 2.4, indicating that merely 0.4% of the acetic acid molecules are dissociated. However, in very dilute (< 10−6 M) solution acetic acid is >90% dissociated.


Structure

In solid acetic acid, the molecules form chains, individual molecules being interconnected by
hydrogen bond A hydrogen bond (or H-bond) is a primarily electrostatic Electrostatics is a branch of physics Physics is the that studies , its , its and behavior through , and the related entities of and . "Physical science is that department ...

hydrogen bond
s. In the vapour at , dimers can be detected. Dimers also occur in the liquid phase in dilute solutions in non-hydrogen-bonding solvents, and a certain extent in pure acetic acid, but are disrupted by hydrogen-bonding solvents. The dissociation
enthalpy Enthalpy , a property of a thermodynamic system, is the sum of the system's internal energy and the product of its pressure and volume. It is a state function used in many measurements in chemical, biological, and physical systems at a constant p ...

enthalpy
of the dimer is estimated at 65.0–66.0 kJ/mol, and the dissociation entropy at 154–157 J mol−1 K−1. Other carboxylic acids engage in similar intermolecular hydrogen bonding interactions.


Solvent properties

Liquid A liquid is a nearly incompressible In fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics Mechanics (Ancient Greek, Greek: ) is the area of physics concerned with the motions of physical objects, ...

Liquid
acetic acid is a
hydrophilic A hydrophile is a molecule File:Pentacene on Ni(111) STM.jpg, A scanning tunneling microscopy image of pentacene molecules, which consist of linear chains of five carbon rings. A molecule is an electrically neutral group of two or more atoms ...

hydrophilic
(
polar Polar may refer to: Geography Polar may refer to: * Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates *Polar climate, the clim ...
)
protic solventA protic solvent is a solvent A solvent (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a ...
, similar to
ethanol Ethanol (also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ (anatomy), ...

ethanol
and
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

water
. With a moderate
relative static permittivity The relative permittivity, or dielectric constant, of a material is its (absolute) permittivity expressed as a ratio relative to the vacuum permittivity. Permittivity is a material property that affects the Coulomb force ''F'' between two poi ...
(dielectric constant) of 6.2, it dissolves not only polar compounds such as inorganic salts and
sugar Sugar is the generic name for sweet-tasting, soluble carbohydrate is a disaccharide A disaccharide (also called a double sugar or ''biose'') is the sugar formed when two monosaccharides are joined by glycosidic linkage. Like monosacc ...

sugar
s, but also non-polar compounds such as oils as well as polar solutes. It is miscible with polar and non-polar
solvent A solvent (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

solvent
s such as water,
chloroform Chloroform, or trichloromethane, is an organic compound with formula CH Cl3. It is a colorless, strong-smelling, dense liquid that is produced on a large scale as a precursor to PTFE Polytetrafluoroethylene (PTFE) is a synthetic fluoropoly ...

chloroform
, and
hexane Hexane () is an organic compound, a straight-chain alkane with six carbon atoms and has the molecular formula C6H14. Hexane is a significant constituent of gasoline. It is a colorless liquid, odorless when pure, and with boiling points approxim ...

hexane
. With higher alkanes (starting with
octane Octane is a hydrocarbon In , a hydrocarbon is an consisting entirely of and . Hydrocarbons are examples of s. Hydrocarbons are generally colourless and hydrophobic with only weak odours. Because of their diverse molecular structures, it is di ...

octane
), acetic acid is not
miscible Miscibility () is the property of two substances to mix in all proportions (that is, to fully dissolve in each other at any concentration In chemistry Chemistry is the study of the properties and behavior of . It is a that covers ...
at all compositions, and solubility of acetic acid in alkanes declines with longer n-alkanes. The solvent and
miscibility Miscibility () is the property of two substances to mix in all proportions (that is, to fully dissolve in each other at any concentration In chemistry, concentration is the abundance of a constituent divided by the total volume of a mixture. ...
properties of acetic acid make it a useful industrial chemical, for example, as a solvent in the production of
dimethyl terephthalate Dimethyl terephthalate (DMT) is an organic compound with the formula C6H4(COOCH3)2. It is the diester formed from terephthalic acid and methanol. It is a white solid that melts to give a distillable colourless liquid.Richard J. Sheehan "Terephth ...
.


Biochemistry

At physiological pHs, acetic acid is usually fully ionised to
acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids) in the periodic table: Metalloids are i ...

acetate
. The
acetyl In organic chemistry Organic chemistry is a branch of chemistry that studies the structure, properties and reactions of organic compounds, which contain carbon in covalent bonding.Clayden, J.; Greeves, N. and Warren, S. (2012) ''Organic Chemis ...

acetyl
group A group is a number A number is a mathematical object used to counting, count, measurement, measure, and nominal number, label. The original examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with ...
, formally derived from acetic acid, is fundamental to all forms of life. When bound to
coenzyme A Coenzyme A (CoA, SHCoA, CoASH) is a coenzyme, notable for its role in the Fatty acid metabolism#Synthesis, synthesis and Fatty acid metabolism#.CE.B2-Oxidation, oxidation of fatty acids, and the oxidation of pyruvic acid, pyruvate in the citric aci ...
, it is central to the
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life Life is a characteristic that distinguishes physical entities A bubble of exhaled gas in water In common usage and classical mechanics, a phys ...

metabolism
of
carbohydrate A carbohydrate () is a biomolecule , showing alpha helices, represented by ribbons. This poten was the first to have its suckture solved by X-ray crystallography by Max Perutz and Sir John Cowdery Kendrew in 1958, for which they received a ...
s and
fat In nutrition Nutrition is the biochemical Biochemistry or biological chemistry, is the study of chemical processes within and relating to living organisms. A sub-discipline of both chemistry and biology, biochemistry may be divided ...

fat
s. Unlike longer-chain carboxylic acids (the
fatty acids In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence in ...
), acetic acid does not occur in natural
triglyceride A triglyceride (TG, triacylglycerol, TAG, or triacylglyceride) is an ester An ester is a derived from an (organic or inorganic) in which at least one –OH group is replaced by an –O– () group, as in the substitution reaction of a an ...

triglyceride
s. However, the artificial triglyceride (glycerine triacetate) is a common food additive and is found in cosmetics and topical medicines. Acetic acid is produced and
excreted Excretion is a process in which metabolic waste is eliminated from an organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμός, ''organismos'') is any individual contiguous system that embodies the Life#Biology, p ...
by
acetic acid bacteria Acetic acid bacteria (AAB) are a group of Gram-negative Gram-negative bacteria are bacteria Bacteria (; common noun bacteria, singular bacterium) are a type of Cell (biology), biological cell. They constitute a large domain (biology), do ...
, notably the genus ''
Acetobacter ''Acetobacter'' is a genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also refer ...
'' and ''
Clostridium acetobutylicum ''Clostridium acetobutylicum'', ATCC 824, is a commercially valuable bacterium Bacteria (; common noun bacteria, singular bacterium) are a type of Cell (biology), biological cell. They constitute a large domain (biology), domain of proka ...

Clostridium acetobutylicum
''. These bacteria are found universally in
food Food is any substance consumed to provide Nutrient, nutritional support for an organism. Food is usually of plant, animal or Fungus, fungal origin, and contains essential nutrients, such as carbohydrates, fats, protein (nutrient), proteins, vi ...

food
stuffs,
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

water
, and
soil Soil is a mixture 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, comp ...

soil
, and acetic acid is produced naturally as fruits and other foods spoil. Acetic acid is also a component of the
vaginal lubrication Vaginal lubrication is a naturally produced fluid that a . Vaginal lubrication is always present, but production increases significantly near and during in anticipation of . Vaginal dryness is the condition in which this lubrication is insuff ...

vaginal lubrication
of
human Humans (''Homo sapiens'') are the most abundant and widespread species In biology, a species is the basic unit of biological classification, classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A speci ...

human
s and other
primate A primate ( ) (from Latin , from 'prime, first rank') is a eutherian mammal constituting the Taxonomy (biology), taxonomic order (biology), order Primates (). Primates arose 85–55 million years ago first from small Terrestrial animal, ...

primate
s, where it appears to serve as a mild
antibacterial An antibiotic is a type of antimicrobial An antimicrobial is an agent that kills microorganism A microorganism, or microbe,, ''mikros'', "small") and ''organism In biology, an organism (from Ancient Greek, Greek: ὀργανισμ ...
agent.


Production

Acetic acid is produced industrially both synthetically and by bacterial
fermentation Fermentation is a metabolism, metabolic process that produces chemical changes in organic Substrate (chemistry), substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in ...
. About 75% of acetic acid made for use in the chemical industry is made by the
carbonylation Carbonylation refers to reaction Reaction may refer to a process or to a response to an action, event, or exposure: Physics and chemistry *Chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic tra ...
of
methanol Methanol, also known as methyl alcohol, amongst other names, is a chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be se ...

methanol
, explained below. The biological route accounts for only about 10% of world production, but it remains important for the production of vinegar because many food purity laws require vinegar used in foods to be of biological origin. Other processes are methyl formate isomerization, conversion of syngas to acetic acid, and gas phase oxidation of ethylene and ethanol. Acetic acid is often a side product of different reactions, i.e. during heterogeneous catalytic acrylic acid synthesis or fermentative lactic acid production. As of 2003–2005, total worldwide production of virgin acetic acid was estimated at 5 Mt/a (million tonnes per year), approximately half of which was produced in the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...

United States
.
Europe Europe is a continent A continent is any of several large landmass A landmass, or land mass, is a large region In geography Geography (from Greek: , ''geographia'', literally "earth description") is a field of scienc ...

Europe
an production was approximately 1 Mt/a and declining, while
Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an in ...

Japan
ese production was 0.7 Mt/a. Another 1.5 Mt were recycled each year, bringing the total world market to 6.5 Mt/a. Since then the global production has increased to 10.7 Mt/a (in 2010), and further; however, a slowing in this increase in production is predicted. The two biggest producers of virgin acetic acid are
Celanese Celanese Corporation, formerly known as Hoechst Celanese, is a Fortune 500 The ''Fortune'' 500 is an annual list compiled and published by ''Fortune Fortune may refer to: General * Fortuna or Fortune, the Roman goddess of luck * Luck, a cha ...
and Chemicals. Other major producers include
Millennium Chemicals Millennium Inorganic Chemicals is a Hunt Valley, Maryland based chemical company. The business was established in 1985. It was a subsidiary of United Kingdom, British conglomerate Hanson plc at one time, but was demerged on 1 October 1996, when i ...
, Sterling Chemicals,
Samsung The Samsung Group (or simply Samsung) ( ko, 삼성) is a South Korean Multinational corporation, multinational manufacturing Conglomerate (company), conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affil ...

Samsung
,
EastmanEastman may refer to: People * Eastman (surname) * Eastman Jacobs, Eastman Nixon Jacobs (1902–1987), American aerodynamicist * Eastman Johnson, Jonathan Eastman Johnson (1824–1906), American painter * George Eastman (1854-1932), American entrep ...
, and Svensk Etanolkemi.


Methanol carbonylation

Most acetic acid is produced by methanol
carbonylation Carbonylation refers to reaction Reaction may refer to a process or to a response to an action, event, or exposure: Physics and chemistry *Chemical reaction A chemical reaction is a process that leads to the IUPAC nomenclature for organic tra ...
. In this process,
methanol Methanol, also known as methyl alcohol, amongst other names, is a chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be se ...

methanol
and
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom. It is the simplest molecule of the oxocarbon family. In ...

carbon monoxide
react to produce acetic acid according to the equation: : The process involves
iodomethane Iodomethane, also called methyl iodide, and commonly abbreviated "MeI", is the chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entity, molecular entities) composed of atoms from ...

iodomethane
as an intermediate, and occurs in three steps. A
catalyst Catalysis () is the process of increasing the rate of a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter In cla ...

catalyst
,
metal carbonyl Metal carbonyls are coordination complex A coordination complex consists of a central 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 ...
, is needed for the carbonylation (step 2). #CH3OH + HI → CH3I + H2O #CH3I + CO → CH3COI #CH3COI + H2O → CH3COOH + HI Two related processes for the carbonylation of methanol: the rhodium-catalyzed
Monsanto process The Monsanto Company () was an American agrochemical An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical A chemical substance is a form of matter having constant chemical composition and characteristi ...
, and the iridium-catalyzed
Cativa process 200px, Space-filling model of the greener and more efficient and has largely supplanted the former process, often in the same production plants. Catalytic amounts of water are used in both processes, but the Cativa process requires less, so the water-gas shift reaction is suppressed, and fewer by-products are formed. By altering the process conditions,
acetic anhydride Acetic anhydride, or ethanoic anhydride, is the 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, ...

acetic anhydride
may also be produced on the same plant using the rhodium catalysts.


Acetaldehyde oxidation

Prior to the commercialization of the Monsanto process, most acetic acid was produced by oxidation of
acetaldehyde Ethanal (common name acetaldehyde) is an organic chemical compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds ...
. This remains the second-most-important manufacturing method, although it is usually not competitive with the carbonylation of methanol. The acetaldehyde can be produced by hydration of acetylene. This was the dominant technology in the early 1900s. Light
naphtha Naphtha ( or ) is a flammable liquid hydrocarbon mixture. Mixtures labelled ''naphtha'' have been produced from natural gas condensate Natural-gas condensate, also called natural gas liquids, is a low-density mixture of hydrocarbon In , a ...
components are readily oxidized by oxygen or even air to give
peroxides Peroxides are a group of compounds with the structure R−O−O−R, where R = any element. The O−O group in a peroxide is called the peroxide group or peroxo group. The nomenclature is somewhat variable. The most common peroxide is hydrogen ...
, which decompose to produce acetic acid according to the
chemical equation A chemical equation is the symbolic representation of a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter In classical ...
, illustrated with butane: : 2 C4H10 + 5 O2 → 4 CH3CO2H + 2 H2O Such oxidations require metal catalyst, such as the naphthenate
salt Salt is a mineral In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure fo ...
s of
manganese Manganese is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical e ...

manganese
,
cobalt Cobalt is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical element ...

cobalt
, and
chromium Chromium is a chemical element upright=1.0, 500px, The chemical elements ordered by link=Periodic table In chemistry Chemistry is the science, scientific study of the properties and behavior of matter. It is a natural science tha ...

chromium
. The typical reaction is conducted at
temperature Temperature ( ) is a physical quantity that expresses hot and cold. It is the manifestation of thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical concept ...

temperature
s and pressures designed to be as hot as possible while still keeping the butane a liquid. Typical reaction conditions are and 55 atm. Side-products may also form, including
butanone Butanone, also known as methyl ethyl ketone (MEK), is an organic compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, com ...
,
ethyl acetate Ethyl acetate ( systematically ethyl ethanoate, commonly abbreviated EtOAc, ETAC or EA) is the organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), million ...

ethyl acetate
,
formic acid Formic acid, systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH. It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. The word "formic" comes ...

formic acid
, and
propionic acid Propionic acid (, from the Greek#REDIRECT Greek Greek may refer to: Greece Anything of, from, or related to Greece Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its population ...

propionic acid
. These side-products are also commercially valuable, and the reaction conditions may be altered to produce more of them where needed. However, the separation of acetic acid from these by-products adds to the cost of the process. Under similar conditions and using similar
catalyst Catalysis () is the process of increasing the rate of a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter In cla ...

catalyst
s as are used for butane oxidation, the
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
in
air The atmosphere of Earth is the layer of gas Gas is one of the four fundamental states of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (ph ...

air
to produce acetic acid can oxidize
acetaldehyde Ethanal (common name acetaldehyde) is an organic chemical compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds ...
. : 2 CH3CHO + O2 → 2 CH3CO2H Using modern catalysts, this reaction can have an acetic acid yield greater than 95%. The major side-products are
ethyl acetate Ethyl acetate ( systematically ethyl ethanoate, commonly abbreviated EtOAc, ETAC or EA) is the organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), million ...

ethyl acetate
,
formic acid Formic acid, systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH. It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. The word "formic" comes ...

formic acid
, and
formaldehyde Formaldehyde ( , also ) (systematic nameA systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance A chemical substance is a form of matter In classical physics and general chemist ...
, all of which have lower
boiling point The boiling point of a substance is the temperature at which the vapor pressure 280px, The ''pistol test tube'' experiment. The tube contains alcohol and is closed with a piece of cork. By heating the alcohol, the vapors fill in the space, inc ...
s than acetic acid and are readily separated by
distillation Distillation, or classical distillation, is the process of separating the components or substances from a liquid mixture In chemistry, a mixture is a material made up of two or more different chemical substances which are not chemically com ...

distillation
.


Ethylene oxidation

Acetaldehyde may be prepared from
ethylene Ethylene (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the authoritativ ...

ethylene
via the Wacker process, and then oxidised as above. In more recent times, chemical company
Showa Denko , founded in 1939 by the merger of Nihon Electrical Industries and Showa Fertilizers, both established by a Japan , image_flag = Flag of Japan.svg , alt_flag = Centered deep red circle on a white rectang ...

Showa Denko
, which opened an ethylene oxidation plant in Ōita,
Japan Japan ( ja, 日本, or , and formally ) is an island country An island country or an island nation is a country A country is a distinct territory, territorial body or political entity. It is often referred to as the land of an in ...

Japan
, in 1997, commercialised a cheaper single-stage conversion of ethylene to acetic acid. The process is catalyzed by a
palladium Palladium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical elem ...

palladium
metal catalyst supported on a
heteropoly acid In chemistry, a heteropolymetalate is a subset of the polyoxometalates. They consist of three or more transition metal oxyanions linked together by shared oxygen atoms to form closed 3-dimensional molecular framework. In contrast to isopolymetalat ...
such as
silicotungstic acid Silicotungstic acid (also known as tungstosilicic acid) is a heteropoly acid In chemistry, a heteropolymetalate is a subset of the polyoxometalates. They consist of three or more transition metal oxyanions linked together by shared oxygen atoms ...
. Similar process use the same metal catalyst on silicotungstic acid and silica: :C2H4 + O2 → CH3CO2H It is thought to be competitive with methanol carbonylation for smaller plants (100–250 kt/a), depending on the local price of ethylene. The approach will be based on utilizing a novel selective photocatalytic oxidation technology for the selective oxidation of ethylene and ethane to acetic acid. Unlike traditional oxidation catalysts, the selective oxidation process will use UV light to produce acetic acid at ambient temperatures and pressure.


Oxidative fermentation

For most of human history, acetic acid bacteria of the genus ''
Acetobacter ''Acetobacter'' is a genus Genus (plural genera) is a taxonomic rank Taxonomy (general) is the practice and science of classification of things or concepts, including the principles that underlie such classification. The term may also refer ...
'' have made acetic acid, in the form of vinegar. Given sufficient oxygen, these bacteria can produce vinegar from a variety of alcoholic foodstuffs. Commonly used feeds include
apple cider Apple cider (also called sweet cider or soft cider or simply cider) is the name used in the United States and Canada for an unfiltered, unsweetened, non-alcoholic beverage made from apples. Though typically referred to simply as "cider" in the Un ...

apple cider
,
wine Wine is an alcoholic drink An alcoholic drink is a drink A drink (or beverage) is a liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flow ...

wine
, and fermented
grain A grain is a small, hard, dry seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double albu ...

grain
,
malt Malt is germinated cereal grain that has been dried in a process known as "malting Malting is a process of steeping Steeping is the soaking of an organic solid, such as leaves, in a liquid (usually water) to extract flavours or to soft ...
,
rice Rice is the seed A seed is an embryonic ''Embryonic'' is the twelfth studio album by experimental rock band the Flaming Lips released on October 13, 2009, on Warner Bros. Records, Warner Bros. The band's first double album, it was relea ...

rice
, or
potato The potato is a starch#Food, starchy tuber of the plant ''Solanum tuberosum'' and is a root vegetable native to the Americas. The plant is a perennial plant, perennial in the nightshade family Solanaceae. Wild potato species can be found thro ...

potato
mashes. The overall chemical reaction facilitated by these bacteria is: : C2H5OH + O2 → CH3COOH + H2O A dilute alcohol solution inoculated with ''Acetobacter'' and kept in a warm, airy place will become vinegar over the course of a few months. Industrial vinegar-making methods accelerate this process by improving the supply of
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
to the bacteria. The first batches of vinegar produced by fermentation probably followed errors in the
winemaking Winemaking or vinification is the production of wine Wine is an alcoholic drink typically made from Fermentation in winemaking, fermented grapes. Yeast in winemaking, Yeast consumes the sugar in the grapes and converts it to ethanol and ca ...
process. If
must Must (from the Latin ''vinum mustum'', "young wine") is freshly crushed fruit juice Juice is a drink A drink (or beverage) is a liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics ...

must
is fermented at too high a temperature, acetobacter will overwhelm the
yeast Yeasts are eukaryotic Eukaryotes () are organism In biology Biology is the natural science that studies life and living organisms, including their anatomy, physical structure, Biochemistry, chemical processes, Molecular ...
naturally occurring on the
grapes A grape is a fruit In botany Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term ...

grapes
. As the demand for vinegar for culinary, medical, and sanitary purposes increased, vintners quickly learned to use other organic materials to produce vinegar in the hot summer months before the grapes were ripe and ready for processing into wine. This method was slow, however, and not always successful, as the vintners did not understand the process. One of the first modern commercial processes was the "fast method" or "German method", first practised in Germany in 1823. In this process, fermentation takes place in a tower packed with wood shavings or
charcoal Charcoal is a lightweight black carbon Carbon (from la, carbo "coal") is a with the C and 6. It is lic and —making four s available to form s. It belongs to group 14 of the periodic table. Carbon makes up only about 0.025 perc ...

charcoal
. The alcohol-containing feed is trickled into the top of the tower, and fresh
air The atmosphere of Earth is the layer of gas Gas is one of the four fundamental states of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (ph ...

air
supplied from the bottom by either natural or forced
convection Convection is single or multiphase fluid flow that occurs Spontaneous process, spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When t ...

convection
. The improved air supply in this process cut the time to prepare vinegar from months to weeks. Nowadays, most vinegar is made in submerged tank
culture Culture () is an umbrella term which encompasses the social behavior and Norm (social), norms found in human Society, societies, as well as the knowledge, beliefs, arts, laws, Social norm, customs, capabilities, and habits of the individuals i ...
, first described in 1949 by Otto Hromatka and Heinrich Ebner. In this method, alcohol is fermented to vinegar in a continuously stirred tank, and oxygen is supplied by bubbling air through the solution. Using modern applications of this method, vinegar of 15% acetic acid can be prepared in only 24 hours in batch process, even 20% in 60-hour fed-batch process.


Anaerobic fermentation

Species of
anaerobic bacteria An anaerobic organism or anaerobe is any organism that does not require oxygen for growth. It may react negatively or even die if free oxygen is present. In contrast, an aerobic organism (aerobe) is an organism that requires an oxygenated environme ...

anaerobic bacteria
, including members of the genus ''
Clostridium ''Clostridium'' is a genus Genus /ˈdʒiː.nəs/ (plural genera /ˈdʒen.ər.ə/) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, virus ...
'' or ''
Acetobacterium ''Acetobacterium'' is a genus of anaerobic, Gram-positive bacteria that belong to the Eubacteriaceae family. The type species of this genus is ''Acetobacterium woodii''. The name, ''Acetobacterium'', has originated because they are acetogens, p ...
'' can convert sugars to acetic acid directly without creating ethanol as an intermediate. The overall chemical reaction conducted by these bacteria may be represented as: : C6H12O6 → 3 CH3COOH These acetogenic bacteria produce acetic acid from one-carbon compounds, including methanol,
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom. It is the simplest molecule of the oxocarbon family. In ...

carbon monoxide
, or a mixture of
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

carbon dioxide
and
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

hydrogen
: : 2 CO2 + 4 H2 → CH3COOH + 2 H2O This ability of ''Clostridium'' to metabolize sugars directly, or to produce acetic acid from less costly inputs, suggests that these bacteria could produce acetic acid more efficiently than ethanol-oxidizers like ''Acetobacter''. However, ''Clostridium'' bacteria are less acid-tolerant than ''Acetobacter''. Even the most acid-tolerant ''Clostridium'' strains can produce vinegar in concentrations of only a few per cent, compared to ''Acetobacter'' strains that can produce vinegar in concentrations up to 20%. At present, it remains more cost-effective to produce vinegar using ''Acetobacter'', rather than using ''Clostridium'' and concentrating it. As a result, although acetogenic bacteria have been known since 1940, their industrial use is confined to a few niche applications.


Uses

Acetic acid is a chemical
reagent A reagent is a substance or compound added to a system to cause a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter ...
for the production of chemical compounds. The largest single use of acetic acid is in the production of vinyl acetate
monomer In chemistry Chemistry is the scientific Science () is a systematic enterprise that builds and organizes knowledge Knowledge is a familiarity or awareness, of someone or something, such as facts A fact is an occurrence in th ...

monomer
, closely followed by acetic anhydride and ester production. The volume of acetic acid used in vinegar is comparatively small.


Vinyl acetate monomer

The primary use of acetic acid is the production of
vinyl acetate Vinyl acetate is an organic compound with the Chemical formula, formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate and ethylene-vinyl acetate, ethene-vinyl acetate copolymers, important industrial polymers. Producti ...

vinyl acetate
monomer (VAM). In 2008, this application was estimated to consume a third of the world's production of acetic acid. The reaction consists of
ethylene Ethylene (IUPAC The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering OrganizationsNational Adhering Organizations in chemistry are the organizations that work as the authoritativ ...

ethylene
and acetic acid with
oxygen Oxygen is the chemical element Image:Simple Periodic Table Chart-blocks.svg, 400px, Periodic table, The periodic table of the chemical elements In chemistry, an element is a pure substance consisting only of atoms that all have the same ...

oxygen
over a
palladium Palladium is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical elem ...

palladium
catalyst Catalysis () is the process of increasing the rate of a chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter In cla ...

catalyst
, conducted in the gas phase. : 2 H3C−COOH + 2 C2H4 + O2 → 2 H3C−CO−O−CH=CH2 + 2 H2O Vinyl acetate can be polymerised to
polyvinyl acetate Polyvinyl acetate (PVA, PVAc, poly(ethenyl ethanoate)), commonly known as wood glue, white glue, carpenter's glue, school glue, or Elmer's glue in the US, is a widely available adhesive used for porous materials like wood, paper, and cloth. An a ...

polyvinyl acetate
or other
polymers A polymer (; Greek ''wikt:poly-, poly-'', "many" + ''wikt:-mer, -mer'', "part") is a Chemical substance, substance or material consisting of very large molecules, or macromolecules, composed of many Repeat unit, repeating subunits. Due to thei ...

polymers
, which are components in
paint Paint is any pigmented liquid A liquid is a nearly incompressible In fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics Mechanics (Ancient Greek, Greek: ) is the area of physics concerned wi ...

paint
s and
adhesive Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advantag ...
s.


Ester production

The major
ester An ester is a derived from an (organic or inorganic) in which at least one –OH group is replaced by an –O– () group, as in the substitution reaction of a and an . s are s of ; they are important in biology, being one of the main classe ...

ester
s of acetic acid are commonly used as solvents for
ink Ink is a gel, Sol (colloid), sol, or Solution (chemistry), solution that contains at least one colourant, such as a dye or pigment, and is used to color a surface to produce an image, writing, text, or design. Ink is used for drawing or writing ...

ink
s,
paint Paint is any pigmented liquid A liquid is a nearly incompressible In fluid mechanics Fluid mechanics is the branch of physics concerned with the mechanics Mechanics (Ancient Greek, Greek: ) is the area of physics concerned wi ...

paint
s and
coating A coating is a covering that is applied to the surface of an object, usually referred to as the Substrate (materials science), substrate. The purpose of applying the coating may be decorative, functional, or both. Paints and lacquers are coating ...
s. The esters include
ethyl acetate Ethyl acetate ( systematically ethyl ethanoate, commonly abbreviated EtOAc, ETAC or EA) is the organic compound In , organic compounds are generally any s that contain - . Due to carbon's ability to (form chains with other carbon s), million ...

ethyl acetate
, ''n''-
butyl acetate ''n''-Butyl acetate, also known as butyl ethanoate, is an ester that is a colorless, flammable liquid at room temperature. It is found in many types of fruit, where along with other chemicals, it imparts characteristic flavors and has a sweet sm ...

butyl acetate
,
isobutyl acetate The chemical compound isobutyl acetate, also known as 2-methylpropyl ethanoate (IUPAC name) or β-methylpropyl acetate, is a common solvent. It is produced from the esterification of isobutanol with acetic acid. It is used as a solvent for lacquer ...

isobutyl acetate
, and
propyl acetate Propyl acetate, also known as propyl ethanoate, is an organic compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compou ...

propyl acetate
. They are typically produced by
catalyzed that utilizes a low-temperature oxidation catalyst to convert carbon monoxide to less toxic carbon dioxide at room temperature. It can also remove formaldehyde from the air. Catalysis () is the process of increasing the reaction rate, rate of a ...

catalyzed
reaction from acetic acid and the corresponding
alcohol 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 originally referred to the primary alcohol ethan ...

alcohol
: : H3C−COOH + HO−R → H3C−CO−O−R + H2O, (R = a general
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 ...
) Most acetate esters, however, are produced from
acetaldehyde Ethanal (common name acetaldehyde) is an organic chemical compound , CH4; is among the simplest organic compounds. In chemistry Chemistry is the scientific discipline involved with Chemical element, elements and chemical compound, compounds ...
using the
Tishchenko reaction The Tishchenko reaction is an organic chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substance A chemical substance is a form of matter In classical physics and gener ...

Tishchenko reaction
. In addition, ether acetates are used as solvents for
nitrocellulose Nitrocellulose (also known as cellulose nitrate, flash paper, flash cotton, guncotton, pyroxylin and flash string, depending on form) is a highly flammable compound formed by nitrating In organic chemistry, nitration is a general class of chem ...

nitrocellulose
, acrylic lacquers,
varnish Varnish is a clear transparent Transparency, transparence or transparent most often refer to transparency and translucency, the physical property of allowing the transmission of light through a material. They may also refer to: Literal uses ...

varnish
removers, and wood stains. First, glycol monoethers are produced from
ethylene oxide Ethylene oxide is an organic compound 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, beh ...

ethylene oxide
or
propylene oxide Propylene oxide is an organic compound 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, beha ...

propylene oxide
with alcohol, which are then esterified with acetic acid. The three major products are ethylene glycol monoethyl ether acetate (EEA), ethylene glycol monobutyl ether acetate (EBA), and propylene glycol monomethyl ether acetate (PMA, more commonly known as PGMEA in semiconductor manufacturing processes, where it is used as a resist solvent). This application consumes about 15% to 20% of worldwide acetic acid. Ether acetates, for example EEA, have been shown to be harmful to human reproduction.


Acetic anhydride

The product of the
condensation Condensation is the change of the state of matter In physics Physics is the natural science that studies matter, its Elementary particle, fundamental constituents, its Motion (physics), motion and behavior through Spacetime, space ...
of two molecules of acetic acid is
acetic anhydride Acetic anhydride, or ethanoic anhydride, is the 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, ...

acetic anhydride
. The worldwide production of acetic anhydride is a major application, and uses approximately 25% to 30% of the global production of acetic acid. The main process involves dehydration of acetic acid to give
ketene A ketene is an 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 properties, reactions, and sy ...

ketene
at 700–750 °C. Ketene is thereafter reacted with acetic acid to obtain the anhydride: :CH3CO2H → CH2=C=O + H2O :CH3CO2H + CH2=C=O → (CH3CO)2O Acetic anhydride is an
acetylation Acetylation (or in IUPAC nomenclature The International Union of Pure and Applied Chemistry The International Union of Pure and Applied Chemistry (IUPAC ) is an international federation of National Adhering Organizations that represents chemi ...

acetylation
agent. As such, its major application is for
cellulose acetate Cellulose acetate refers to any acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids ...

cellulose acetate
, a synthetic
textile A textile is a flexible material made by creating an interlocking bundle of yarn Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, ...

textile
also used for
photographic film Photographic film is a strip or sheet of transparent film baseA film base is a transparent substrate which acts as a support medium for the photosensitive emulsion An emulsion is a mixture of two or more liquids that are normally Miscibil ...
. Acetic anhydride is also a reagent for the production of
heroin Heroin, also known as diacetylmorphine and diamorphine among other names, is an opioid Opioids are substances that act on opioid receptor Opioid receptors are a group of inhibitory G protein-coupled receptors with opioids as ligands. T ...

heroin
and other compounds.


Use as solvent

Glacial acetic acid is an excellent polar
protic solventA protic solvent is a solvent A solvent (from the Latin language, Latin ''wikt:solvo#Latin, solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a ...
, as noted #Solvent properties, above. It is frequently used as a solvent for recrystallization (chemistry), recrystallization to purify organic compounds. Acetic acid is used as a
solvent A solvent (from the Latin Latin (, or , ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken in the area around Rome, known as Latium. Through the power of the ...

solvent
in the production of terephthalic acid (TPA), the raw material for polyethylene terephthalate (PET). In 2006, about 20% of acetic acid was used for TPA production. Acetic acid is often used as a solvent for reactions involving carbocations, such as Friedel-Crafts#Friedel–Crafts alkylation, Friedel-Crafts alkylation. For example, one stage in the commercial manufacture of synthetic camphor involves a Wagner-Meerwein rearrangement of camphene to isobornyl acetate; here acetic acid acts both as a solvent and as a nucleophile to trap the rearrangement reaction, rearranged carbocation. Glacial acetic acid is used in analytical chemistry for the estimation of weakly alkaline substances such as organic amides. Glacial acetic acid is a much weaker base (chemistry), base than water, so the amide behaves as a strong base in this medium. It then can be titrated using a solution in glacial acetic acid of a very strong acid, such as perchloric acid.


Medical use

Acetic acid injection into a tumor has been used to treat cancer since the 1800s. Acetic acid is used as part of cervical cancer screening in many areas in the developing world. The acid is applied to the cervix and if an area of white appears after about a minute the test is positive. Acetic acid is an effective antiseptic when used as a 1% solution, with broad spectrum of activity against streptococci, staphylococci, pseudomonas, enterococci and others. It may be used to treat skin infections caused by pseudomonas strains resistant to typical antibiotics. While diluted acetic acid is used in iontophoresis, no high quality evidence supports this treatment for rotator cuff disease. As a treatment for otitis externa, it is on the WHO Model List of Essential Medicines, World Health Organization's List of Essential Medicines, the safest and most effective medicines needed in a health system.


Foods

Acetic acid has 349 kcal per 100 g. Vinegar is typically no less than 4% acetic acid by mass. Legal limits on acetic acid content vary by jurisdiction. Vinegar is used directly as a condiment, and in the pickling of vegetables and other foods. Table vinegar tends to be more diluted (4% to 8% acetic acid), while commercial food pickling employs solutions that are more concentrated. The proportion of acetic acid used worldwide as vinegar is not as large as commercial uses, but is by far the oldest and best-known application.


Reactions


Organic chemistry

Acetic acid undergoes the typical chemical reactions of a carboxylic acid. Upon treatment with a standard base, it converts to metal
acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids) in the periodic table: Metalloids are i ...

acetate
and
water Water (chemical formula H2O) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known li ...

water
. With strong bases (e.g., organolithium reagents), it can be doubly deprotonated to give LiCH2CO2Li. Reduction of acetic acid gives ethanol. The OH group is the main site of reaction, as illustrated by the conversion of acetic acid to acetyl chloride. Other substitution derivatives include
acetic anhydride Acetic anhydride, or ethanoic anhydride, is the 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, ...

acetic anhydride
; this anhydride is produced by Condensation reaction, loss of water from two molecules of acetic acid. Esters of acetic acid can likewise be formed via Fischer esterification, and amides can be formed. When heated above , acetic acid decomposes to produce
carbon dioxide Carbon dioxide (chemical formula A chemical formula is a way of presenting information about the chemical proportions of s that constitute a particular or molecule, using symbols, numbers, and sometimes also other symbols, such as pare ...

carbon dioxide
and methane, or to produce
ketene A ketene is an 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 properties, reactions, and sy ...

ketene
and water: :CH3COOH → CH4 + CO2 :CH3COOH → CH2CO + H2O


Reactions with inorganic compounds

Acetic acid is mildly corrosion, corrosive to metals including iron, magnesium, and zinc, forming
hydrogen Hydrogen is the chemical element with the Symbol (chemistry), symbol H and atomic number 1. Hydrogen is the lightest element. At standard temperature and pressure, standard conditions hydrogen is a gas of diatomic molecules having the che ...

hydrogen
gas and salts called
acetate An acetate is a salt formed by the combination of acetic acid with a base (e.g. alkaline, earthy, metallic, nonmetal image:Simple Periodic Table Chart-en.svg, upright=1.75, Nonmetals (and metalloids) in the periodic table: Metalloids are i ...

acetate
s: : Mg + 2 CH3COOH → (CH3COO)2Mg + H2 Because aluminium forms a Passivation (chemistry), passivating acid-resistant film of aluminium oxide, aluminium tanks are used to transport acetic acid. Metal acetates can also be prepared from acetic acid and an appropriate Base (chemistry), base, as in the popular "Sodium bicarbonate, baking soda + vinegar" reaction: : NaHCO3 + CH3COOH → CH3COONa + CO2 + H2O A colour reaction for salts of acetic acid is iron(III) chloride solution, which results in a deeply red colour that disappears after acidification. A more sensitive test uses lanthanum nitrate with iodine and ammonia to give a blue solution. Acetates when heated with arsenic trioxide form cacodyl oxide, which can be detected by its odour, malodorous vapours.


Other derivatives

Organic or inorganic salts are produced from acetic acid. Some commercially significant derivatives: *Sodium acetate, used in the
textile A textile is a flexible material made by creating an interlocking bundle of yarn Yarn is a long continuous length of interlocked fibres, suitable for use in the production of textiles, sewing, crocheting, knitting, weaving, embroidery, ...

textile
industry and as a food preservative (E number, E262). *Copper(II) acetate, used as a pigment and a fungicide. *Aluminium acetate and iron(II) acetate—used as mordants for dyes. *Palladium(II) acetate, used as a catalyst for organic coupling reactions such as the Heck reaction. Halogenated acetic acids are produced from acetic acid. Some commercially significant derivatives: *Chloroacetic acid (monochloroacetic acid, MCA), dichloroacetic acid (considered a by-product), and trichloroacetic acid. MCA is used in the manufacture of indigo dye. *Bromoacetic acid, which is esterified to produce the reagent ethyl bromoacetate. *Trifluoroacetic acid, which is a common reagent in organic synthesis. Amounts of acetic acid used in these other applications together account for another 5–10% of acetic acid use worldwide.


History

Vinegar Vinegar is an aqueous solution of acetic acid and trace compounds that may include flavorings. Vinegar typically contains 5–8% acetic acid by volume. Usually, the acetic acid is produced by a double fermentation; converting simple sugars to eth ...

Vinegar
was known early in civilization as the natural result of exposure of beer and
wine Wine is an alcoholic drink An alcoholic drink is a drink A drink (or beverage) is a liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flow ...

wine
to air, because acetic acid-producing bacteria are present globally. The use of acetic acid in alchemy extends into the 3rd century BC, when the Greece, Greek philosopher Theophrastus described how vinegar acted on metals to produce pigments useful in art, including ''white lead'' (lead carbonate) and ''verdigris'', a green mixture of copper salts including copper(II) acetate. Ancient Rome, Romans boiled soured wine to produce a highly sweet syrup called ''sapa''. Defrutum, Sapa that was produced in lead pots was rich in Lead(II) acetate, lead acetate, a sweet substance also called ''sugar of lead'' or ''sugar of Saturn (mythology), Saturn'', which contributed to lead poisoning among the Roman aristocracy. In the 16th-century Germany, German alchemist Andreas Libavius described the production of acetone from the dry distillation of lead acetate, ketonic decarboxylation. The presence of water in vinegar has such a profound effect on acetic acid's properties that for centuries chemists believed that glacial acetic acid and the acid found in vinegar were two different substances. French chemist Pierre Adet proved them identical. In 1845 German chemist Hermann Kolbe Chemical synthesis, synthesised acetic acid from inorganic compounds for the first time. This reaction sequence consisted of chlorination reaction, chlorination of carbon disulfide to carbon tetrachloride, followed by pyrolysis to tetrachloroethylene and aqueous chlorination to trichloroacetic acid, and concluded with electrolysis, electrolytic organic redox reaction, reduction to acetic acid. By 1910, most glacial acetic acid was obtained from the pyroligneous acid, pyroligneous liquor, a product of the distillation of wood. The acetic acid was isolated by treatment with limewater, milk of lime, and the resulting calcium acetate was then acidified with sulfuric acid to recover acetic acid. At that time, Germany was producing 10,000 tons of glacial acetic acid, around 30% of which was used for the manufacture of indigo dye. Because both
methanol Methanol, also known as methyl alcohol, amongst other names, is a chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be se ...

methanol
and
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom. It is the simplest molecule of the oxocarbon family. In ...

carbon monoxide
are commodity raw materials, methanol carbonylation long appeared to be attractive precursors to acetic acid. Henri Dreyfus at British Celanese developed a methanol carbonylation pilot plant as early as 1925. However, a lack of practical materials that could contain the corrosive reaction mixture at the high pressures needed (200 Atmosphere (unit), atm or more) discouraged commercialization of these routes. The first commercial methanol carbonylation process, which used a
cobalt Cobalt is a chemical element In chemistry, an element is a pure Chemical substance, substance consisting only of atoms that all have the same numbers of protons in their atomic nucleus, nuclei. Unlike chemical compounds, chemical element ...

cobalt
catalyst, was developed by German chemical company BASF in 1963. In 1968, a rhodium-based catalyst (''cis''−[Rh(CO)2I2]) was discovered that could operate efficiently at lower pressure with almost no by-products. US chemical company Monsanto Company built the first plant using this catalyst in 1970, and rhodium-catalyzed methanol carbonylation became the dominant method of acetic acid production (see
Monsanto process The Monsanto Company () was an American agrochemical An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical A chemical substance is a form of matter having constant chemical composition and characteristi ...
). In the late 1990s, the chemicals company Chemicals commercialised the Cativa process, Cativa catalyst ([Ir(CO)2I2]), which is promoted by iridium for greater efficiency. This iridium-catalyzed
Cativa process 200px, Space-filling model of the [Ir(CO)2I2sup>− catalyst used in the Cativa process The Cativa process is a method for the production of acetic acid by the carbonylation of methanol. The technology, which is similar to the Monsanto process, wa ...
is Green chemistry, greener and more efficient and has largely supplanted the Monsanto process, often in the same production plants.


Interstellar medium

Interstellar medium, Interstellar acetic acid was discovered in 1996 by a team led by David Mehringer using the former Berkeley-Illinois-Maryland Association array at the Hat Creek Radio Observatory and the former Millimeter Array located at the Owens Valley Radio Observatory. It was first detected in the Sagittarius B2 North molecular cloud (also known as the Sgr B2 Large Molecule Heimat source). Acetic acid has the distinction of being the first molecule discovered in the interstellar medium using solely Radio telescope#Radio interferometry, radio interferometers; in all previous ISM molecular discoveries made in the millimetre and centimetre wavelength regimes, single dish radio telescopes were at least partly responsible for the detections.


Health effects and safety

Concentrated acetic acid is corrosion, corrosive to skin. These burns or blisters may not appear until hours after exposure. Prolonged inhalation exposure (eight hours) to acetic acid vapours at 10 ppm can produce some irritation of eyes, nose, and throat; at 100 ppm marked lung irritation and possible damage to lungs, eyes, and skin may result. Vapour concentrations of 1,000 ppm cause marked irritation of eyes, nose and upper respiratory tract and cannot be tolerated. These predictions were based on animal experiments and industrial exposure. In 12 workers exposed for two or more years to acetic acid airborne average concentration of 51 ppm (estimated), produced symptoms of conjunctive irritation, upper respiratory tract irritation, and hyperkeratotic dermatitis. Exposure to 50 ppm or more is intolerable to most persons and results in intensive lacrimation and irritation of the eyes, nose, and throat, with pharyngeal oedema and chronic bronchitis. Unacclimatised humans experience extreme eye and nasal irritation at concentrations in excess of 25 ppm, and conjunctivitis from concentrations below 10 ppm has been reported. In a study of five workers exposed for seven to 12 years to concentrations of 80 to 200 ppm at peaks, the principal findings were blackening and hyperkeratosis of the skin of the hands, conjunctivitis (but no corneal damage), bronchitis and pharyngitis, and erosion of the exposed teeth (incisors and canines). The hazards of solutions of acetic acid depend on the concentration. The following table lists the Directive 67/548/EEC, EU classification of acetic acid solutions: Concentrated acetic acid can be ignited only with difficulty at standard temperature and pressure, but becomes a flammable risk in temperatures greater than , and can form explosive mixtures with air at higher temperatures (explosive limits: 5.4–16%).


See also

*Acetic acid (data page) *Acetyl group, the CH3-CO– group *Acids in wine *Acetate


References


External links

*
National Pollutant Inventory – Acetic acid fact sheetMethod for sampling and analysis29 CFR 1910.1000, Table Z-1
(US Permissible exposure limits)

*Calculation o
vapor pressureliquid densitydynamic liquid viscositysurface tension
of acetic acid
Acetic acid bound to proteins
in the Protein Data Bank, PDB
Swedish Chemicals Agency. Information sheet – Acetic Acid
* Process Flow sheet of Acetic acid Production by th
Carbonylation of Methanol
{{portal bar, Medicine Acetic acids, Acids in wine Antiseptics Commodity chemicals E-number additives Flavors Household chemicals Otologicals Photographic chemicals Solvents World Health Organization essential medicines