Gluconic Acid Formula – Structure, Uses, Properties

Gluconic acid formula is known for its chelating properties and is used in various industrial and food applications, including as a food additive and a cleaning agent.

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Gluconic Acid Formula It is an organic compound. It is also one of 16 stereoisomers of 2, 3, 4, 5, 6-pental-hydroxyhexanoic acid. Furthermore, gluconic acid forms the gluconate ion in aqueous solution at a neutral pH. In addition, we know the salts of gluconic acid as ‘gluconates’. Gluconates are also used to inject drugs into the body.

Gluconic Acid Formula And Structure

This chemical compound has the molecular formula C6H12O7 and the condensed structural formula HOCH2(CHOH)4COOH. Its chemical structure consists of six carbon chains with five hydroxyl groups (OH), which are arranged in the same manner as in the open chained form of glucose, ending in a carboxylic acid group. Gluconic acid is also in equilibrium with the cyclic ester of gluconic delta-lactone in aqueous solution. The molar mass of the ester is 196.16 g/mol.

Gluconic Acid Formula

Occurrence of Gluconic Acid

As the result of glucose oxidation, gluconate salts, gluconate esters, and gluconic acid are widely found in nature. In 1929, Horace Terhune Herrick developed a method that could produce its salts by fermentation. However, gluconic acid naturally occurs in fruits, honey, and wine. In addition to acting as an acidity regulator, it is also a food additive (E574).

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Preparation of Gluconic Acid

A carboxylic acid that forms naturally in honey, wine, fruits, and many other foods is gluconic acid. It is a nontoxic compound that can be found in nature. A mixture of bromide and sulfuric acid can also be used to synthesize glucose, which is a carboxylic acid. In addition, it can also be prepared by gamma irradiation of D-glucose with a bromine water solution. Oxidation of glucose in bromine water yields glucose acid.

Gluconic acid production relies on the fermentative oxidation of glucose’s aldehyde group obtained from corn. This process is carried out by various fungi including Aspergillus niger, Aspergillus fumaricus, and Penicillium chryrosogenum. In addition to this method, gluconic acid and sorbitol can also be formed through the Cannizaro reaction using glucose under alkaline conditions. Another option for its preparation is through the electrolytic oxidation of glucose in an alkaline environment. Alternatively, it can be chemically oxidized using a hypochlorite or hypobromite solution or directly oxidized with a palladium catalyst present.

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Physical Properties of Gluconic Acid

Chemical Formula  C6H12O7 
IUPAC Name D-Gluconic acid
Systematic IUPAC name (2R,3S,4R,5R)-2,3,4,5,6-Pentahydroxyhexanoic acid
Molar mass 196.155 g/mol 
Appearance Colourless crystals
Taste Mild acid taste
Density 1.23 mg/mL
Melting point 131 °C
Solubility Soluble in water, slightly soluble in alcohol, and insoluble in ether  
Acidity (pKa) 3.86
Refractive index 1.4161
Hydrogen bond donor count  6
Hydrogen bond acceptor count  7
Rotatable Bond Count 5

Chemical Properties of Gluconic Acid

As a result of neutralizing gluconic acid with lime or calcium carbonate, calcium gluconate is formed. An aqueous solution of ferrous carbonate and gluconic acid can be used to produce ferrous gluconate or iron (II) gluconate. In water, gluconic acid partially forms an equilibrium mixture with gamma and delta gluconolactone.

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Uses of Gluconic Acid

  • Gluconic acid has a wide range of applications, such as in industrial cleaning, textile bleach stabilization, aluminum processing, and as a chelating agent for cement set retarding. 
  • It is also utilized in metal surface treatment, cleaning and personal care products, pharmaceuticals, and as a food additive. 
  • In addition, calcium gluconate is administered to patients with hypocalcemia while its gel form is used in treating burns caused by hydrofluoric acid. Another gluconic acid derivative, quinine gluconate, is commonly used to treat malaria. 
  • Ferrous gluconate (also known as iron (II) gluconate) injections have been considered as a potential solution for anemia resulting from iron deficiency. 
  • To top it off, the aqueous solution of gluconic acid serves as an effective medium for organic synthesis.

Gluconic Acid Formula FAQs

What is the chemical formula of gluconic acid?

The chemical formula of gluconic acid is C6H12O7.

Is gluconic acid a natural compound?

Yes, gluconic acid is a naturally occurring organic acid found in various fruits, honey, and wine.

What is the primary use of gluconic acid?

Gluconic acid is commonly used as a food additive and in cleaning products due to its chelating and mild acidic properties.

Is gluconic acid safe for consumption?

The FDA generally recognizes gluconic acid as safe (GRAS) when used in food and beverage products within specified limits.

How does gluconic acid contribute to its chelating properties?

Gluconic acid forms stable complexes with metal ions, making it effective in removing mineral deposits and stains, which is why it's used in cleaning agents.

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