Sodium formate, HCOONa, is the sodium salt of
formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...
, HCOOH. It usually appears as a white
deliquescent
Hygroscopy is the phenomenon of attracting and holding water molecules via either absorption or adsorption from the surrounding environment, which is usually at normal or room temperature. If water molecules become suspended among the substance' ...
powder.
Preparation
For commercial use, sodium formate is produced by absorbing
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 ...
under pressure in solid
sodium hydroxide at 130 °C and 6-8 bar pressure:
[Arnold Willmes, ''Taschenbuch Chemische Substanzen'', Harri Deutsch, Frankfurt (M.), 2007.]
:CO + NaOH → HCO
2Na
Because of the low-cost and large-scale availability of
formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...
by carbonylation of methanol and hydrolysis of the resulting methyl formate, sodium formate is usually prepared by
neutralizing
A neutralizing antibody (NAb) is an antibody that defends a cell from a pathogen or infectious particle by neutralizing any effect it has biologically. Neutralization renders the particle no longer infectious or pathogenic.
Neutralizing antibod ...
formic acid with
sodium hydroxide. Sodium formate is also unavoidably formed as a by-product in the final step of the
pentaerythritol
Pentaerythritol is an organic compound with the formula C(CH2OH)4. Classified as a polyol, it is a white solid. Pentaerythritol is a building block for the synthesis and production of explosives, plastics, paints, appliances, cosmetics, and many o ...
synthesis and in the crossed
Cannizzaro reaction
The Cannizzaro reaction, named after its discoverer Stanislao Cannizzaro, is a chemical reaction which involves the base-induced disproportionation of two molecules of a non-enolizable aldehyde to give a primary alcohol and a carboxylic acid.
...
of
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 ...
with the aldol reaction product trimethylol acetaldehyde
-hydroxy-2,2-bis(hydroxymethyl)propanal
In the laboratory, sodium formate can be prepared by neutralizing
formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...
with
sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
. It can also be obtained by reacting
chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to ...
with an alcoholic solution of
sodium hydroxide.
::CHCl
3 + 4 NaOH → HCOONa + 3 NaCl + 2 H
2O
or by reacting
sodium hydroxide with
chloral hydrate
Chloral hydrate is a geminal diol with the formula . It is a colorless solid. It has limited use as a sedative and hypnotic pharmaceutical drug. It is also a useful laboratory chemical reagent and precursor. It is derived from chloral (trichl ...
.
::C
2HCl
3(OH)
2 + NaOH → CHCl
3 + HCOONa + H
2O
The latter method is, in general, preferred to the former because the low aqueous solubility of
CHCl3 makes it easier to separate out from the sodium formate solution, by
fractional crystallization, than the soluble
NaCl
Sodium chloride , commonly known as salt (although sea salt also contains other chemical salts), is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. With molar masses of 22.99 and 35.45 g ...
would be.
Sodium formate may also be created via the
haloform reaction
In chemistry, the haloform reaction is a chemical reaction in which a haloform (, where X is a halogen) is produced by the exhaustive halogenation of an acetyl group (, where R can be either a hydrogen atom, an alkyl or an aryl group), in the ...
between
ethanol
Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...
and
sodium hypochlorite
Sodium hypochlorite (commonly known in a dilute solution as bleach) is an Inorganic chemistry, inorganic chemical compound with the chemical formula, formula NaOCl (or NaClO), comprising a sodium cation () and a hypochlorite anion (or ). It may ...
in the presence of a
base. This procedure is well documented for the preparation of
chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to ...
.
Properties
Physical properties
![Sodium formate dihydrate](https://upload.wikimedia.org/wikipedia/commons/e/e7/Sodium_formate_dihydrate.jpg)
Sodium formate crystallizes in a
monoclinic crystal system
In crystallography, the monoclinic crystal system is one of the seven crystal systems. A crystal system is described by three vectors. In the monoclinic system, the crystal is described by vectors of unequal lengths, as in the orthorhombic sy ...
with the
lattice parameter
A lattice constant or lattice parameter is one of the physical dimensions and angles that determine the geometry of the unit cells in a crystal lattice, and is proportional to the distance between atoms in the crystal. A simple cubic crystal has o ...
s a = 6,19 Å, b = 6,72 Å, c = 6,49 Å and β = 121,7°.
[W. H. Zachariasen: "The Crystal Structure of Sodium Formate, NaHCO2" in '']J. Am. Chem. Soc.
The ''Journal of the American Chemical Society'' is a weekly peer-reviewed scientific journal that was established in 1879 by the American Chemical Society. The journal has absorbed two other publications in its history, the ''Journal of Analytic ...
'', 1940, ''62''(5), S. 1011–1013.
Chemical properties
On heating, sodium formate decomposes to form
sodium oxalate
Sodium oxalate, or disodium oxalate, is the sodium salt of oxalic acid with the formula Na2C2O4. It is a white, crystalline, odorless solid, that decomposes above 290 °C.
Disodium oxalate can act as a reducing agent, and it may be used as a pr ...
and hydrogen.
The resulting sodium oxalate can be converted by further heating to
sodium carbonate
Sodium carbonate, , (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula Na2CO3 and its various hydrates. All forms are white, odourless, water-soluble salts that yield moderately alkaline solutions ...
upon release of carbon monoxide:
[T. Yoshimori, Y. Asano, Y. Toriumi, T. Shiota: "Investigation on the drying and decomposition of sodium oxalate" in '']Talanta
''Talanta'' is a peer-reviewed scientific journal in pure and applied analytical chemistry. It was established in 1958 and is published by Elsevier, with 15 issues per year. In addition to original research articles, ''Talanta'' also publishes revi ...
'' 1978, ''25''(10) S. 603-605. [T. Meisel, Z. Halmos, K. Seybold, E. Pungor: "The thermal decomposition of alkali metal formates" in '']Journal of Thermal Analysis and Calorimetry
The ''Journal of Thermal Analysis and Calorimetry'' is a peer-reviewed scientific journal published by Springer Science+Business Media in cooperation with Akadémiai Kiadó. Formerly this journal was known as ''Journal of Thermal Analysis''. It ...
'' 1975, ''7''(1). S. 73-80.
:
2HCOONa ->Delta
Delta commonly refers to:
* Delta (letter) (Δ or δ), a letter of the Greek alphabet
* River delta, at a river mouth
* D ( NATO phonetic alphabet: "Delta")
* Delta Air Lines, US
* Delta variant of SARS-CoV-2 that causes COVID-19
Delta may also ...
+ H2\!\uparrow
:
(COO)2Na2 -> \ \ce">\atop >\ \ce + CO\!\uparrow
As a
salt
Salt is a mineral composed primarily of sodium chloride (NaCl), a chemical compound belonging to the larger class of salts; salt in the form of a natural crystalline mineral is known as rock salt or halite. Salt is present in vast quantitie ...
of a weak acid (
formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...
) and a
strong base (
sodium hydroxide) sodium formate reacts in aqueous solutions basic:
:
HCOO^- + H2O <<=> HCOOH + OH^-
A solution of formic acid and sodium formate can thus be used as a
buffer
Buffer may refer to:
Science
* Buffer gas, an inert or nonflammable gas
* Buffer solution, a solution used to prevent changes in pH
* Buffering agent, the weak acid or base in a buffer solution
* Lysis buffer, in cell biology
* Metal ion buffer
* ...
solution.
Sodium formate is slightly water-hazardous and inhibits some species of bacteria but is degraded by others.
Uses
Sodium formate is used in several fabric dyeing and printing processes. It is also used as a
buffering agent
A buffer solution (more precisely, pH buffer or hydrogen ion buffer) is an aqueous solution consisting of a mixture of a weak acid and its conjugate base, or vice versa. Its pH changes very little when a small amount of strong acid or base is a ...
for strong mineral acids to increase their
pH, as a food additive (E237), and as a
de-icing
Deicing is the process of removing snow, ice or frost from a surface. Anti-icing is the application of chemicals that not only deice but also remain on a surface and continue to delay the reformation of ice for a certain period of time, or prev ...
agent.
In
structural biology
Structural biology is a field that is many centuries old which, and as defined by the Journal of Structural Biology, deals with structural analysis of living material (formed, composed of, and/or maintained and refined by living cells) at every le ...
, sodium formate can be used as a
cryoprotectant
A cryoprotectant is a substance used to protect biological tissue from freezing damage (i.e. that due to ice formation). Arctic and Antarctic insects, fish and amphibians create cryoprotectants (antifreeze, antifreeze compounds and antifreeze prot ...
for X-ray diffraction experiments on protein crystals, which are typically conducted at a temperature of 100 K to reduce the effects of
radiation damage
Radiation damage is the effect of ionizing radiation on physical objects including non-living structural materials. It can be either detrimental or beneficial for materials.
Radiobiology is the study of the action of ionizing radiation on livin ...
.
Sodium formate plays a role in the
synthesis
Synthesis or synthesize may refer to:
Science Chemistry and biochemistry
*Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors
** Organic synthesis, the chemical synthesis of organ ...
of
formic acid
Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Es ...
, it is converted by sulfuric acid via the following reaction equation:
:
:
Sodium formate is converted with sulfuric acid to formic acid and sodium sulfate
Sodium sulfate (also known as sodium sulphate or sulfate of soda) is the inorganic compound with formula Na2SO4 as well as several related hydrates. All forms are white solids that are highly soluble in water. With an annual production of 6 milli ...
.
The
urticating hair
Urticating hairs or urticating bristles are one of the primary defense mechanisms used by numerous plants, almost all New World tarantulas, and various lepidopteran caterpillars. ''Urtica'' is Latin for "nettle" (stinging nettles are in the genu ...
of
stinging nettles contain sodium formate as well as formic acid.
Solid sodium formate is used as a non-corrosive agent at
airport
An airport is an aerodrome with extended facilities, mostly for commercial air transport. Airports usually consists of a landing area, which comprises an aerially accessible open space including at least one operationally active surface ...
s for de-icing of runways in mix with corrosion inhibitors and other additives, which rapidly penetrate solid snow and ice layers, detach them from the asphalt or concrete and melt the ice rapidly. Sodium formate was also used as a road deicer in the city of
Ottawa
Ottawa (, ; Canadian French: ) is the capital city of Canada. It is located at the confluence of the Ottawa River and the Rideau River in the southern portion of the province of Ontario. Ottawa borders Gatineau, Quebec, and forms the core ...
from 1987 to 1988.
The high freezing point depression e.g. in comparison to the still frequently used
urea
Urea, also known as carbamide, is an organic compound with chemical formula . This amide has two amino groups (–) joined by a carbonyl functional group (–C(=O)–). It is thus the simplest amide of carbamic acid.
Urea serves an important r ...
(which is effective but problematic due to
eutrophication
Eutrophication is the process by which an entire body of water, or parts of it, becomes progressively enriched with minerals and nutrients, particularly nitrogen and phosphorus. It has also been defined as "nutrient-induced increase in phytopla ...
) effectively prevents the re-icing, even at temperatures below −15 °C. The thawing effect of the solid sodium formate can even be increased by moistening with aqueous
potassium formate
Potassium formate, HCO2K, HCOOK, or CHKO2, is the potassium salt of formic acid. This strongly hygroscopic white solid is an intermediate in the formate potash process for the production of potassium. Potassium formate has also been studied as a ...
or
potassium acetate
Potassium acetate (CH3COOK) is the potassium salt of acetic acid. It is a hygroscopic solid at room temperature.
Preparation
It can be prepared by treating a potassium-containing base such as potassium hydroxide or potassium carbonate with acetic ...
solutions. The degradability of sodium formate is particularly advantageous with a chemical oxygen demand (COD) of 211 mg
O2/g compared with the de-icing agents
sodium acetate
Sodium acetate, CH3COONa, also abbreviated Na O Ac, is the sodium salt of acetic acid. This colorless deliquescent salt has a wide range of uses.
Applications
Biotechnological
Sodium acetate is used as the carbon source for culturing bacteria ...
(740 mg O
2/g) and urea with (> 2,000 mg O
2/g).
Saturated sodium formate solutions (as well as mixtures of other alkali metal formates such as potassium and cesium formate) are used as important drilling and stabilizing aids in gas and
oil exploration
Hydrocarbon exploration (or oil and gas exploration) is the search by petroleum geologists and geophysicists for deposits of hydrocarbons, particularly petroleum and natural gas, in the Earth using petroleum geology.
Exploration methods
Vis ...
because of their relatively high density. By mixing the corresponding saturated alkali metal formate solutions any densities between 1,0 and 2,3 g/cm
3 can be set. The saturated solutions are
biocidal and
long-term stable against microbial degradation. Diluted, on the other hand, they are fast and completely biodegradable. As alkali metal formates as drilling aids make it unnecessary to add solid fillers to increase the density (such as
baryte
Baryte, barite or barytes ( or ) is a mineral consisting of barium sulfate ( Ba S O4). Baryte is generally white or colorless, and is the main source of the element barium. The ''baryte group'' consists of baryte, celestine (strontium sulfate), ...
s) and the formate solutions can be recovered and
recycled
Recycling is the process of converting waste materials into new materials and objects. The recovery of energy from waste materials is often included in this concept. The recyclability of a material depends on its ability to reacquire the p ...
at the drilling site, formates represent an important advance in exploration technology.
[William Benton and Jim Turner, Cabot Specialty Fluids]
Cesium formate fluid succeeds in North Sea HPHT field trials
(PDF; 88 kB); In: Drilling Contractor, Mai/Juni 2000.
See also
*
Sodium acetate
Sodium acetate, CH3COONa, also abbreviated Na O Ac, is the sodium salt of acetic acid. This colorless deliquescent salt has a wide range of uses.
Applications
Biotechnological
Sodium acetate is used as the carbon source for culturing bacteria ...
References
{{Authority control
Formates
Organic sodium salts
Deliquescent substances