Names | |||
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Systematic IUPAC name Sodium methanoate | |||
Other names
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Identifiers | |||
3D model (JSmol) | |||
ChEBI | |||
ChEMBL | |||
ChemSpider | |||
ECHA InfoCard | 100.004.990 | ||
EC Number |
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E number | E237 (preservatives) | ||
PubChem CID | |||
UNII | |||
CompTox Dashboard (EPA) | |||
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Properties | |||
HCOONa | |||
Molar mass | 68.007 g/mol | ||
Appearance | white granules deliquescent | ||
Density | 1.92 g/cm3 (20 °C) | ||
Melting point | 253 °C (487 °F; 526 K) | ||
Boiling point | decomposes | ||
43.82 g/100 mL (0 °C) 97.2 g/100 mL (20 °C) 160 g/100 mL (100 °C) | |||
Solubility | insoluble in ether soluble in glycerol, alcohol, formic acid | ||
Thermochemistry | |||
Heat capacity (C) | 82.7 J/mol K | ||
Std molar entropy (S⦵298) | 103.8 J/mol K | ||
Std enthalpy of formation (ΔfH⦵298) | -666.5 kJ/mol | ||
Gibbs free energy (ΔfG⦵) | -599.9 kJ/mol | ||
Hazards | |||
NFPA 704 (fire diamond) | |||
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). |
Sodium formate, HCOONa, is the sodium salt of formic acid, HCOOH. It usually appears as a white deliquescent powder.
For commercial use, sodium formate is produced by absorbing carbon monoxide under pressure in solid sodium hydroxide at 130 °C and 6-8 bar pressure: [1]
Because of the low-cost and large-scale availability of formic acid by carbonylation of methanol and hydrolysis of the resulting methyl formate, sodium formate is usually prepared by neutralizing formic acid with sodium hydroxide. Sodium formate is also unavoidably formed as a by-product in the final step of the pentaerythritol synthesis and in the crossed Cannizzaro reaction of formaldehyde with the aldol reaction product trimethylol acetaldehyde [3-hydroxy-2,2-bis(hydroxymethyl)propanal]. [2]
In the laboratory, sodium formate can be prepared by neutralizing formic acid with sodium carbonate. It can also be obtained by reacting chloroform with an alcoholic solution of sodium hydroxide.
or by reacting sodium hydroxide with chloral hydrate.
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 would be.
Sodium formate crystallizes in a monoclinic crystal system with the lattice parameters a = 6,19 Å, b = 6,72 Å, c = 6,49 Å and β = 121,7°. [3]
On heating, sodium formate decomposes to form sodium oxalate and hydrogen. [4] The resulting sodium oxalate can be converted by further heating to sodium carbonate upon release of carbon monoxide: [5] [4]
As a salt of a weak acid (formic acid) and a strong base (sodium hydroxide) sodium formate reacts in aqueous solutions basic:
A solution of formic acid and sodium formate can thus be used as a buffer solution.
Sodium formate is slightly water-hazardous and inhibits some species of bacteria but is degraded by others.
Sodium formate is used in several fabric dyeing and printing processes. It is also used as a buffering agent for strong mineral acids to increase their pH, as a food additive (E237), and as a de-icing agent.
In structural biology, sodium formate can be used as a cryoprotectant for X-ray diffraction experiments on protein crystals, [6] which are typically conducted at a temperature of 100 K to reduce the effects of radiation damage.
Sodium formate plays a role in the synthesis of formic acid, it is converted by sulfuric acid via the following reaction equation:
The urticating hair of stinging nettles contain sodium formate as well as formic acid.
Solid sodium formate is used as a non-corrosive agent at airports 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 from 1987 to 1988. [7]
The high freezing point depression e.g. in comparison to the still frequently used urea (which is effective but problematic due to eutrophication) 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 or potassium acetate 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 (740 mg O2/g) and urea with (> 2,000 mg O2/g). [8]
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 because of their relatively high density. By mixing the corresponding saturated alkali metal formate solutions any densities between 1,0 and 2,3 g/cm3 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 barytes) and the formate solutions can be recovered and recycled at the drilling site, formates represent an important advance in exploration technology. [9]
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen ion, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid.
In chemistry, an acid–base reaction is a chemical reaction that occurs between an acid and a base. It can be used to determine pH via titration. Several theoretical frameworks provide alternative conceptions of the reaction mechanisms and their application in solving related problems; these are called the acid–base theories, for example, Brønsted–Lowry acid–base theory.
Hydroxide is a diatomic anion with chemical formula OH−. It consists of an oxygen and hydrogen atom held together by a single covalent bond, and carries a negative electric charge. It is an important but usually minor constituent of water. It functions as a base, a ligand, a nucleophile, and a catalyst. The hydroxide ion forms salts, some of which dissociate in aqueous solution, liberating solvated hydroxide ions. Sodium hydroxide is a multi-million-ton per annum commodity chemical. The corresponding electrically neutral compound HO• is the hydroxyl radical. The corresponding covalently bound group –OH of atoms is the hydroxy group. Both the hydroxide ion and hydroxy group are nucleophiles and can act as catalysts in organic chemistry.
Hydrolysis is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile.
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations Na+ and hydroxide anions OH−.
Sodium chloride, commonly known as table salt, is an ionic compound with the chemical formula NaCl, representing a 1:1 ratio of sodium and chloride ions. Sodium chloride is the salt most responsible for the salinity of seawater and of the extracellular fluid of many multicellular organisms. In its edible form, it is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. Another major application of sodium chloride is deicing of roadways in sub-freezing weather.
In chemistry, there are three definitions in common use of the word "base": Arrhenius bases, Brønsted bases, and Lewis bases. All definitions agree that bases are substances that react with acids, as originally proposed by G.-F. Rouelle in the mid-18th century.
Nitrous acid is a weak and monoprotic acid known only in solution, in the gas phase, and in the form of nitrite salts. It was discovered by Carl Wilhelm Scheele, who called it "phlogisticated acid of niter". Nitrous acid is used to make diazonium salts from amines. The resulting diazonium salts are reagents in azo coupling reactions to give azo dyes.
In chemistry, neutralization or neutralisation is a chemical reaction in which acid and a base react with an equivalent quantity of each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The pH of the neutralized solution depends on the acid strength of the reactants.
The Brønsted–Lowry theory (also called proton theory of acids and bases) is an acid–base reaction theory which was first developed by Johannes Nicolaus Brønsted and Thomas Martin Lowry independently in 1923. The basic concept of this theory is that when an acid and a base react with each other, the acid forms its conjugate base, and the base forms its conjugate acid by exchange of a proton (the hydrogen cation, or H+). This theory generalises the Arrhenius theory.
Classical qualitative inorganic analysis is a method of analytical chemistry which seeks to find the elemental composition of inorganic compounds. It is mainly focused on detecting ions in an aqueous solution, therefore materials in other forms may need to be brought to this state before using standard methods. The solution is then treated with various reagents to test for reactions characteristic of certain ions, which may cause color change, precipitation and other visible changes.
Formate 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.
In organic chemistry, a carboxylate is the conjugate base of a carboxylic acid, RCOO−. It is an ion with negative charge.
Sodium periodate is an inorganic salt, composed of a sodium cation and the periodate anion. It may also be regarded as the sodium salt of periodic acid. Like many periodates, it can exist in two different forms: sodium metaperiodate (formula NaIO4) and sodium orthoperiodate (normally Na2H3IO6, but sometimes the fully reacted salt Na5IO6). Both salts are useful oxidising agents.
Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2SiF
6. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.
The alkali–silica reaction (ASR), also commonly known as concrete cancer, is a deleterious internal swelling reaction that occurs over time in concrete between the highly alkaline cement paste and the reactive amorphous silica found in many common aggregates, given sufficient moisture.
Aluminium formate is the aluminium salt of formic acid, with the chemical formula Al(HCOO)3. It can be produced via the reaction of aluminium soaps and formic acid. Reaction between formic acid and aluminium hydroxide yields Al(HCOO)3(CO2)0.75(H2O)0.25(HCOOH)0.25. Upon activation at 180 °C, guest molecules are removed to obtain Al(HCOO)3.
Aluminium triacetate, formally named aluminium acetate, is a chemical compound with composition Al(CH
3CO
2)
3. Under standard conditions it appears as a white, water-soluble solid that decomposes on heating at around 200 °C. The triacetate hydrolyses to a mixture of basic hydroxide / acetate salts, and multiple species co-exist in chemical equilibrium, particularly in aqueous solutions of the acetate ion; the name aluminium acetate is commonly used for this mixed system.
The nickel organic acid salts are organic acid salts of nickel. In many of these the ionised organic acid acts as a ligand.
Americium(III) hydroxide is a radioactive inorganic compound with the chemical formula Am(OH)3. It consists of one americium atom and three hydroxy groups. It was first discovered in 1944, closely related to the Manhattan Project. However, these results were confidential and were only released to the public in 1945. It was the first isolated sample of an americium compound, and the first americium compound discovered.