Formic acid (), systematically named methanoic acid, is the simplest

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...

, and has the

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

HCOOH and structure . It is an important intermediate in

chemical synthesis As a topic of chemistry, chemical synthesis (or combination) is the artificial execution of chemical reactions to obtain one or several products. This occurs by physical and chemical manipulations usually involving one or more reactions. In moder ...

and occurs naturally, most notably in some ants.

Ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s, salts and the

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

derived from formic acid are called

formate Formate (IUPAC name: methanoate) is the conjugate base of formic acid. Formate is an anion () or its derivatives such as ester of formic acid. The salts and esters are generally colorless.Werner Reutemann and Heinz Kieczka "Formic Acid" in ''Ull ...

s. Industrially, formic acid is produced from

methanol Methanol (also called methyl alcohol and wood spirit, amongst other names) is an organic chemical and the simplest aliphatic alcohol, with the formula C H3 O H (a methyl group linked to a hydroxyl group, often abbreviated as MeOH). It is a ...

Natural occurrence

In nature, formic acid is found in most ants and in stingless bees of the genus ''

Oxytrigona ''Oxytrigona'' is a genus of bees belonging to the family Apidae Apidae is the largest family within the superfamily Apoidea, containing at least 5700 species of bees. The family includes some of the most commonly seen bees, including bumbleb ...

''. Wood ants from the genus ''

Formica ''Formica'' is a genus of ants of the family Formicidae, commonly known as wood ants, mound ants, thatching ants, and field ants. ''Formica'' is the type genus of the Formicidae, and of the subfamily Formicinae. The type species of genus ''For ...

'' can spray formic acid on their prey or to defend the nest. The puss moth caterpillar (''Cerura vinula'') will spray it as well when threatened by predators. It is also found in the

trichome Trichomes (); ) are fine outgrowths or appendages on plants, algae, lichens, and certain protists. They are of diverse structure and function. Examples are hairs, glandular hairs, scales, and papillae. A covering of any kind of hair on a pla ...

s of stinging nettle (''Urtica dioica''). Apart from that, this acid is incorporated in many fruits such as pineapple (0.21mg per 100g), apple (2mg per 100g) and kiwi (1mg per 100g), as well as in many vegetables, namely onion (45mg per 100g), eggplant (1.34 mg per 100g) and, in extremely low concentrations, cucumber (0.11mg per 100g). Formic acid is a naturally occurring component of the

atmosphere An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A s ...

primarily due to forest emissions.

History

Some

alchemists Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim world, ...

and naturalists were aware that ant hills give off an acidic vapor as early as the 15th century. The first person to describe the isolation of this substance (by the distillation of large numbers of ants) was the English naturalist

John Ray John Ray FRS (29 November 1627 – 17 January 1705) was a Christian English naturalist widely regarded as one of the earliest of the English parson-naturalists. Until 1670, he wrote his name as John Wray. From then on, he used 'Ray', after ...

, in 1671. Ants secrete the formic acid for attack and defense purposes. Formic acid was first synthesized from hydrocyanic acid by the French chemist

Joseph Gay-Lussac Joseph Louis Gay-Lussac (, , ; 6 December 1778 – 9 May 1850) was a French chemist and physicist. He is known mostly for his discovery that water is made of two parts hydrogen and one part oxygen (with Alexander von Humboldt), for two laws ...

. In 1855, another French chemist, Marcellin Berthelot, developed a synthesis from

carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...

similar to the process used today. Formic acid was long considered a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

of only minor interest in the chemical industry. In the late 1960s, however, significant quantities became available as a byproduct of

acetic acid Acetic acid , systematically named ethanoic acid , is an acidic, colourless liquid and organic compound with the chemical formula (also written as , , or ). Vinegar is at least 4% acetic acid by volume, making acetic acid the main component ...

production. It now finds increasing use as a preservative and antibacterial in

livestock Livestock are the domesticated animals raised in an agricultural setting to provide labor and produce diversified products for consumption such as meat, eggs, milk, fur, leather, and wool. The term is sometimes used to refer solely to animals ...

feed.

Properties

Formic acid is a colorless liquid having a pungent, penetrating odor at room temperature, comparable to the related

. Formic acid is about ten times stronger than

. It is

miscible Miscibility () is the property of two substances to mix in all proportions (that is, to fully dissolve in each other at any concentration), forming a homogeneous mixture (a solution). The term is most often applied to liquids but also applies ...

with water and most polar

organic Organic may refer to: * Organic, of or relating to an organism, a living entity * Organic, of or relating to an anatomical organ Chemistry * Organic matter, matter that has come from a once-living organism, is capable of decay or is the product ...

solvent A solvent (s) (from the 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 gas, or a supercritical fluid. Water is a solvent for ...

s, and is somewhat soluble in

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ex ...

s. In hydrocarbons and in the vapor phase, it consists of

hydrogen-bond In chemistry, a hydrogen bond (or H-bond) is a primarily electrostatic force of attraction between a hydrogen (H) atom which is covalently bound to a more electronegative "donor" atom or group (Dn), and another electronegative atom bearing ...

ed dimers rather than individual molecules. Owing to its tendency to hydrogen-bond, gaseous formic acid does not obey the

ideal gas law The ideal gas law, also called the general gas equation, is the equation of state of a hypothetical ideal gas. It is a good approximation of the behavior of many gases under many conditions, although it has several limitations. It was first stat ...

. Solid formic acid, which can exist in either of two polymorphs, consists of an effectively endless network of hydrogen-bonded formic acid molecules. Formic acid forms a high-boiling azeotrope with water (22.4%). Liquid formic acid tends to

supercool Supercooling, also known as undercooling, is the process of lowering the temperature of a liquid or a gas below its melting point without it becoming a solid. It achieves this in the absence of a seed crystal or nucleus around which a crystal ...

Chemical reactions

Decomposition

Formic acid readily decomposes by dehydration in the presence of concentrated

sulfuric acid Sulfuric acid (American spelling and the preferred IUPAC name) or sulphuric acid ( Commonwealth spelling), known in antiquity as oil of vitriol, is a mineral acid composed of the elements sulfur, oxygen and hydrogen, with the molecular formu ...

to form

and water: :HCO₂H → H₂O + CO Treatment of formic acid with

is a convenient laboratory source of CO. In the presence of platinum, it decomposes with a release of

hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, an ...

and

carbon dioxide Carbon dioxide (chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transpar ...

. :HCO₂H → H₂ + CO₂ Soluble ruthenium catalysts are also effective. Carbon monoxide free hydrogen has been generated in a very wide pressure range (1–600 bar).

Reactant

Formic acid shares most of the chemical properties of other

s. Because of its high acidity, solutions in alcohols form esters spontaneously. Formic acid shares some of the reducing properties of

aldehyde In organic chemistry, an aldehyde () is an organic compound containing a functional group with the structure . The functional group itself (without the "R" side chain) can be referred to as an aldehyde but can also be classified as a formyl grou ...

s, reducing solutions of metal oxides to their respective metal. Formic acid is a source for a formyl group for example in the

formylation In biochemistry, the addition of a formyl functional group is termed formylation. A formyl functional group consists of a carbonyl bonded to hydrogen. When attached to an R group, a formyl group is called an aldehyde. Formylation has been identi ...

of methylaniline to N-methylformanilide in

toluene Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) at ...

. In synthetic organic chemistry, formic acid is often used as a source of

hydride In chemistry, a hydride is formally the anion of hydrogen( H−). The term is applied loosely. At one extreme, all compounds containing covalently bound H atoms are called hydrides: water (H2O) is a hydride of oxygen, ammonia is a hydride of ...

ion, as in the Eschweiler-Clarke reaction: It is used as a source of hydrogen in

transfer hydrogenation In chemistry, transfer hydrogenation is a chemical reaction involving the addition of hydrogen to a compound from a source other than molecular . It is applied in laboratory and industrial organic synthesis to saturate organic compounds and reduce ...

, as in the

Leuckart reaction The Leuckart reaction is the chemical reaction that converts aldehydes or ketones to amines by reductive amination in the presence of heat. The reaction, named after Rudolf Leuckart, uses either ammonium formate or formamide as the nitrogen donor ...

to make amines, and (in aqueous solution or in its azeotrope with

triethylamine Triethylamine is the chemical compound with the formula N(CH2CH3)3, commonly abbreviated Et3N. It is also abbreviated TEA, yet this abbreviation must be used carefully to avoid confusion with triethanolamine or tetraethylammonium, for which TEA ...

) for hydrogenation of

ketone In organic chemistry, a ketone is a functional group with the structure R–C(=O)–R', where R and R' can be a variety of carbon-containing substituents. Ketones contain a carbonyl group –C(=O)– (which contains a carbon-oxygen double bo ...

Addition to alkenes

Formic acid is unique among the carboxylic acids in its ability to participate in addition reactions with

alkene In organic chemistry, an alkene is a hydrocarbon containing a carbon–carbon double bond. Alkene is often used as synonym of olefin, that is, any hydrocarbon containing one or more double bonds.H. Stephen Stoker (2015): General, Organic, an ...

s. Formic acids and alkenes readily react to form formate

ester In chemistry, an ester is a compound derived from an oxoacid (organic or inorganic) in which at least one hydroxyl group () is replaced by an alkoxy group (), as in the substitution reaction of a carboxylic acid and an alcohol. Glycerides ar ...

s. In the presence of certain acids, including

sulfuric Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula ...

and

hydrofluoric acid Hydrofluoric acid is a Solution (chemistry), solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly Corrosive substance, corrosive. It is used to make most fluorine-containing compounds; examples include th ...

s, however, a variant of the

Koch reaction The Koch reaction is an organic reaction for the synthesis of tertiary carboxylic acids from alcohols or alkenes. The reaction is a strongly acid-catalyzed carbonylation using carbon monoxide, and typically occurs at high pressures ranging from 50 ...

occurs instead, and formic acid adds to the alkene to produce a larger carboxylic acid.

Formic acid anhydride

An unstable

formic anhydride Formic anhydride, also called methanoic anhydride, is an organic compound with the chemical formula and a structural formula of (H(C=O)−)2O. It can be viewed as the anhydride of formic acid (HCOOH). Preparation Formic anhydride can be obtai ...

, H(C=O)−O−(C=O)H, can be obtained by dehydration of formic acid with ''N'',''N′''-dicyclohexylcarbodiimide in ether at low temperature.

Production

In 2009, the worldwide capacity for producing formic acid was per year, roughly equally divided between Europe (, mainly in Germany) and Asia (, mainly in China) while production was below per year in all other continents. It is commercially available in solutions of various concentrations between 85 and 99 w/w %. , the largest producers are BASF, Eastman Chemical Company,

LC Industrial LC or Lc may refer to: Arts and entertainment * Library of Congress Classification, a system of library classification Gaming and play * Lego Chess, a Lego-based chess video game * Lego Creator, a theme of Lego * ''Lego Creator'' (video game), ...

, and

Feicheng Acid Chemicals Feicheng Acid Chemicals () is a chemical company based in Feicheng, Shandong, China. The company was founded in 1994, with registered capital RMB 52.2 million. It is one of Chinese top 500 chemical industry enterprises and has established a ...

, with the largest production facilities in

Ludwigshafen Ludwigshafen, officially Ludwigshafen am Rhein (; meaning " Ludwig's Port upon Rhine"), is a city in the German state of Rhineland-Palatinate, on the river Rhine, opposite Mannheim. With Mannheim, Heidelberg, and the surrounding region, it form ...

( per year, BASF, Germany),

Oulu Oulu ( , ; sv, Uleåborg ) is a city, municipality and a seaside resort of about 210,000 inhabitants in the region of North Ostrobothnia, Finland. It is the most populous city in northern Finland and the fifth most populous in the country after: ...

(, Eastman, Finland),

Nakhon Pathom Nakhon Pathom ( th, นครปฐม, ) is a city (''thesaban nakhon'') in central Thailand, the former capital of Nakhon Pathom province. One of the most important landmarks is the giant Phra Pathommachedi. The city is also home to Thailand's ...

(n/a, LC Industrial), and

Feicheng Feicheng ( zh, s=肥城, p=Féichéng) is a county-level city under the administration of Tai'an City in the west of Shandong Province, China. , the population was 992,000. Part of the Great Wall of Qi starts here and is listed on the People's R ...

(, Feicheng, China). 2010 prices ranged from around €650/tonne (equivalent to around $800/tonne) in Western Europe to $1250/tonne in the United States.

From methyl formate and formamide

When

and

are combined in the presence of a strong base, the result is methyl formate, according to the chemical equation: :CH₃OH + CO → HCO₂CH₃ In industry, this reaction is performed in the liquid phase at elevated pressure. Typical reaction conditions are 80 °C and 40 atm. The most widely used base is sodium methoxide.

Hydrolysis Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution reaction, substitution, elimination reaction, elimination, and solvation reactions in which water ...

of the methyl formate produces formic acid: :HCO₂CH₃ + H₂O → HCOOH + CH₃OH Efficient hydrolysis of methyl formate requires a large excess of water. Some routes proceed indirectly by first treating the methyl formate with

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

to give

formamide Formamide is an amide derived from formic acid. It is a colorless liquid which is miscible with water and has an ammonia-like odor. It is chemical feedstock for the manufacture of sulfa drugs and other pharmaceuticals, herbicides and pesticide ...

, which is then hydrolyzed with

: :HCO₂CH₃ + NH₃ → HC(O)NH₂ + CH₃OH :2 HC(O)NH₂ + 2H₂O + H₂SO₄ → 2HCO₂H + (NH₄)₂SO₄ A disadvantage of this approach is the need to dispose of the ammonium sulfate byproduct. This problem has led some manufacturers to develop energy-efficient methods of separating formic acid from the excess water used in direct hydrolysis. In one of these processes, used by BASF, the formic acid is removed from the water by liquid-liquid extraction with an organic base.

Niche and obsolete chemical routes

By-product of acetic acid production

A significant amount of formic acid is produced as a byproduct in the manufacture of other chemicals. At one time,

was produced on a large scale by oxidation of

alkane In organic chemistry, an alkane, or paraffin (a historical trivial name that also has other meanings), is an acyclic saturated hydrocarbon. In other words, an alkane consists of hydrogen and carbon atoms arranged in a tree structure in which ...

s, by a process that cogenerates significant formic acid. This oxidative route to acetic acid has declined in importance so that the aforementioned dedicated routes to formic acid have become more important.

Hydrogenation of carbon dioxide

The catalytic

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a Catalysis, catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or S ...

of CO₂ to formic acid has long been studied. This reaction can be conducted homogeneously.

Oxidation of biomass

Formic acid can also be obtained by aqueous catalytic partial oxidation of wet biomass by the

OxFA process The OxFA process is a process to produce formic acid from biomass by catalytic oxidation using molecular oxygen or air. Polyoxometalates of the Keggin-type are used as catalysts. OxFA-Process General description Formic acid is obtained by aqueous ...

. A Keggin-type polyoxometalate (H₅PV₂Mo₁₀O₄₀) is used as the homogeneous catalyst to convert sugars, wood, waste paper, or cyanobacteria to formic acid and CO₂ as the sole byproduct. Yields of up to 53% formic acid can be achieved.

Laboratory methods

In the laboratory, formic acid can be obtained by heating

oxalic acid Oxalic acid is an organic acid with the systematic name ethanedioic acid and formula . It is the simplest dicarboxylic acid. It is a white crystalline solid that forms a colorless solution in water. Its name comes from the fact that early inve ...

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

and extraction by steam distillation. Glycerol acts as a catalyst, as the reaction proceeds through a glyceryl oxalate intermediate. If the reaction mixture is heated to higher temperatures, allyl alcohol results. The net reaction is thus: :C₂O₄H₂ → HCO₂H + CO₂ Another illustrative method involves the reaction between

lead formate Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, le ...

and

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The unde ...

, driven by the formation of lead sulfide. :Pb(HCOO)₂ + H₂S → 2HCOOH + PbS

Electrochemical production

It has been reported that formate can be formed by the

electrochemical reduction Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference, as a measurable and quantitative phenomenon, and identifiable chemical change, with the potential difference as an outco ...

of CO₂ (in the form of

bicarbonate In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula . Bicarbonate serves a crucial biochemic ...

) at a

lead Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...

cathode A cathode is the electrode from which a conventional current leaves a polarized electrical device. This definition can be recalled by using the mnemonic ''CCD'' for ''Cathode Current Departs''. A conventional current describes the direction in whi ...

at pH 8.6: : + + 2e⁻ → + 2 or : + + 2e⁻ → + If the feed is and oxygen is evolved at the anode, the total reaction is: : + → + 1/2

Biosynthesis

Formic acid is named after ants which have high concentrations of the compound in their venom. In ants, formic acid is derived from

serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − form un ...

through a

5,10-methenyltetrahydrofolate 5,10-Methenyltetrahydrofolate (5,10-CH=THF) is a form of tetrahydrofolate that is an intermediate in metabolism. 5,10-CH=THF is a coenzyme that accepts and donates methenyl (CH=) groups. It is produced from 5,10-methylenetetrahydrofolate by eith ...

intermediate. The conjugate base of formic acid, formate, also occurs widely in nature. An

assay An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a ...

for formic acid in body fluids, designed for determination of formate after methanol poisoning, is based on the reaction of formate with bacterial

formate dehydrogenase Formate dehydrogenases are a set of enzymes that catalyse the oxidation of formate to carbon dioxide, donating the electrons to a second substrate, such as NAD+ in formate:NAD+ oxidoreductase () or to a cytochrome in formate:ferricytochrome-b1 o ...

Uses

Agriculture

A major use of formic acid is as a

preservative A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by ...

and

antibacterial An antibiotic is a type of antimicrobial substance active against bacteria. It is the most important type of antibacterial agent for fighting bacterial infections, and antibiotic medications are widely used in the treatment and prevention of ...

agent in livestock feed. In Europe, it is applied on silage, including fresh hay, to promote the fermentation of

lactic acid Lactic acid is an organic acid. It has a molecular formula . It is white in the solid state and it is miscible with water. When in the dissolved state, it forms a colorless solution. Production includes both artificial synthesis as well as natu ...

and to suppress the formation of

butyric acid Butyric acid (; from grc, βούτῡρον, meaning "butter"), also known under the systematic name butanoic acid, is a straight-chain alkyl carboxylic acid with the chemical formula CH3CH2CH2CO2H. It is an oily, colorless liquid with an unple ...

; it also allows fermentation to occur quickly, and at a lower temperature, reducing the loss of nutritional value. Formic acid arrests certain decay processes and causes the feed to retain its nutritive value longer, and so it is widely used to preserve winter feed for

cattle Cattle (''Bos taurus'') are large, domesticated, cloven-hooved, herbivores. They are a prominent modern member of the subfamily Bovinae and the most widespread species of the genus ''Bos''. Adult females are referred to as cows and adult mal ...

. In the

poultry Poultry () are domesticated birds kept by humans for their eggs, their meat or their feathers. These birds are most typically members of the superorder Galloanserae (fowl), especially the order Galliformes (which includes chickens, quails, a ...

industry, it is sometimes added to feed to kill ''

E. coli ''Escherichia coli'' (),Wells, J. C. (2000) Longman Pronunciation Dictionary. Harlow ngland Pearson Education Ltd. also known as ''E. coli'' (), is a Gram-negative, facultative anaerobic, rod-shaped, coliform bacterium of the genus ''Escher ...

'' bacteria. Use as a preservative for silage and (other) animal feed constituted 30% of the global consumption in 2009.

Beekeeper A beekeeper is a person who keeps honey bees. Beekeepers are also called honey farmers, apiarists, or less commonly, apiculturists (both from the Latin '' apis'', bee; cf. apiary). The term beekeeper refers to a person who keeps honey bees i ...

s use formic acid as a miticide against the tracheal mite (''

Acarapis woodi ''Acarapis woodi'' is an internal parasite affecting honey bees, the symptoms of infestation was originally observed on the Isle of Wight in 1904, but was not species description, described until 1921. ''Acarapis woodi'' mites live and reproduce ...

'') and the ''Varroa destructor'' mite and ''Varroa jacobsoni'' mite.

Energy

Formic acid can be used in a

fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most batteries in requ ...

(it can be used directly in

formic acid fuel cell Formic acid fuel cells (direct formic acid fuel cells or DFAFCs) are a subcategory of direct liquid-feed fuel cells (DLFCs), in which the liquid fuel is directly oxidized (electrochemically) at the anode instead of reforming to produce hydrogen. For ...

s and indirectly in hydrogen fuel cells). Electrolytic conversion of electrical energy to chemical fuel has been proposed as a large-scale source of formate by various groups. The formate could be used as feed to modified ''

'' bacteria for producing

biomass Biomass is plant-based material used as a fuel for heat or electricity production. It can be in the form of wood, wood residues, energy crops, agricultural residues, and waste from industry, farms, and households. Some people use the terms bi ...

. Natural microbes do exist that can feed on formic acid or formate (see

Methylotroph Methylotrophs are a diverse group of microorganisms that can use reduced one-carbon compounds, such as methanol or methane, as the carbon source for their growth; and multi-carbon compounds that contain no carbon-carbon bonds, such as dimethyl et ...

). Formic acid has been considered as a means of

hydrogen storage Hydrogen storage can be accomplished by several existing methods of holding hydrogen for later use. These include mechanical approaches such as using high pressures and low temperatures, or employing chemical compounds that release H2 upon demand ...

. The co-product of this decomposition, carbon dioxide, can be rehydrogenated back to formic acid in a second step. Formic acid contains 53 g/L hydrogen at room temperature and atmospheric pressure, which is three and a half times as much as compressed hydrogen gas can attain at 350 bar pressure (14.7 g/L). Pure formic acid is a liquid with a

flash point The flash point of a material is the "lowest liquid temperature at which, under certain standardized conditions, a liquid gives off vapours in a quantity such as to be capable of forming an ignitable vapour/air mixture". (EN 60079-10-1) The fl ...

of +69 °C, much higher than that of gasoline (−40 °C) or ethanol (+13 °C). It is possible to use formic acid as an intermediary to produce isobutanol from using microbes.

Artificial photosynthesis

In August 2020 researchers at Cambridge University announced a stand-alone advanced 'photosheet' technology that converts sunlight, carbon dioxide and water into oxygen and formic acid with no other inputs.

Soldering

Formic acid has a potential application in

soldering Soldering (; ) is a process in which two or more items are joined by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Unlike welding, soldering does not involv ...

. Due to its capacity to reduce oxide layers, formic acid gas can be blasted at an oxide surface in order to increase solder wettability.

Chromatography

Formic acid used as a volatile pH modifier in

HPLC High-performance liquid chromatography (HPLC), formerly referred to as high-pressure liquid chromatography, is a technique in analytical chemistry used to separate, identify, and quantify each component in a mixture. It relies on pumps to pa ...

and

capillary electrophoresis Capillary electrophoresis (CE) is a family of electrokinetic separation methods performed in submillimeter diameter capillaries and in micro- and nanofluidic channels. Very often, CE refers to capillary zone electrophoresis (CZE), but other electr ...

. Formic acid is often used as a component of mobile phase in reversed-phase high-performance liquid chromatography (RP-HPLC) analysis and separation techniques for the separation of hydrophobic macromolecules, such as peptides, proteins and more complex structures including intact viruses. Especially when paired with mass spectrometry detection, formic acid offers several advantages over the more traditionally used phosphoric acid.

Other uses

Formic acid is also significantly used in the production of leather, including

tanning Tanning may refer to: *Tanning (leather), treating animal skins to produce leather *Sun tanning, using the sun to darken pale skin **Indoor tanning, the use of artificial light in place of the sun **Sunless tanning, application of a stain or dye t ...

(23% of the global consumption in 2009), and in dyeing and finishing textiles (9% of the global consumption in 2009) because of its acidic nature. Use as a coagulant in the

production of rubber Rubber, also called India rubber, latex, Amazonian rubber, ''caucho'', or ''caoutchouc'', as initially produced, consists of polymers of the organic compound isoprene, with minor impurities of other organic compounds. Thailand, Malaysia, and ...

consumed 6% of the global production in 2009. Formic acid is also used in place of mineral acids for various cleaning products, such as limescale remover and toilet bowl cleaner. Some formate esters are artificial flavorings and perfumes. Formic acid application has been reported to be an effective treatment for warts.

Safety

Formic acid has low toxicity (hence its use as a food additive), with an of 1.8g/kg (tested orally on mice). The concentrated acid is corrosive to the skin. Formic acid is readily metabolized and eliminated by the body. Nonetheless, it has specific

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

effects; the formic acid and

formaldehyde Formaldehyde ( , ) (systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section F ...

produced as metabolites of

are responsible for the

optic nerve In neuroanatomy, the optic nerve, also known as the second cranial nerve, cranial nerve II, or simply CN II, is a paired cranial nerve that transmits visual system, visual information from the retina to the brain. In humans, the optic nerve i ...

damage, causing blindness, seen in

methanol poisoning Methanol toxicity (also ''methanol poisoning'') is poisoning from methanol, characteristically via ingestion. Symptoms may include a decreased level of consciousness, poor or no coordination, hypothermia, vomiting, abdominal pain, and a specific s ...

. Some chronic effects of formic acid exposure have been documented. Some experiments on bacterial species have demonstrated it to be a

mutagen In genetics, a mutagen is a physical or chemical agent that permanently changes nucleic acid, genetic material, usually DNA, in an organism and thus increases the frequency of mutations above the natural background level. As many mutations can ca ...

. Chronic exposure in humans may cause kidney damage. Another possible effect of chronic exposure is development of a skin

allergy Allergies, also known as allergic diseases, refer a number of conditions caused by the hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include hay fever, food allergies, atopic derma ...

that manifests upon re-exposure to the chemical. Concentrated formic acid slowly decomposes to carbon monoxide and water, leading to pressure buildup in the containing vessel. For this reason, 98% formic acid is shipped in plastic bottles with self-venting caps. The hazards of solutions of formic acid depend on the concentration. The following table lists the

Globally Harmonized System of Classification and Labelling of Chemicals The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is an internationally agreed-upon standard managed by the United Nations that was set up to replace the assortment of hazardous material classification and labelli ...

for formic acid solutions: Formic acid in 85% concentration is flammable, and diluted formic acid is on the U.S. Food and Drug Administration list of food additives., The principal danger from formic acid is from skin or eye contact with the concentrated liquid or vapors. The U.S.

OSHA OSHA or Osha may refer to: Work * Occupational Safety and Health Administration, a federal agency of the United States that regulates workplace safety and health * Occupational Safety and Health Act (United States) of 1970, a federal law in the Un ...

Permissible Exposure Level ( PEL) of formic acid vapor in the work environment is 5 parts per million parts of air ( ppm).

References

External links

International Chemical Safety Card 0485

{{DEFAULTSORT:Formic Acid Alkanoic acids Solvents Cleaning product components Organic compounds with 1 carbon atom