Preparation of Gluconic Acid
Gluconic acid is a non-toxic compound that can be found naturally in honey, wine, fruits, etc. It is a carboxylic acid that can be formed by the oxidation of the first carbon of glucose with antiseptic and chelating properties. It can also be synthesized by hydrolysis of α-D-glucose with a mixture of bromide and sulfuric acid. It can also be prepared by gamma-irradiation of D-glucose. Gluconic acid is produced by oxidizing glucose in the presence of bromine water.
At present, gluconic acid is synthesized in commercial quantities by the fermentative oxidation of the aldehyde group in glucose from corn, which is carried out by Aspergillus niger, Aspergillus fumaricus, Aspergillus acetic, Penicillium chryrosogenum, and other pencillia. Gluconic acid and sorbitol are formed by the Cannizaro reaction on glucose, under alkaline conditions. It may also be prepared from the electrolytic oxidation of glucose in an alkaline medium. Or it can also be prepared by the chemical oxidation of glucose by a hypochlorite or hypobromite solution, or by directly oxidizing glucose in the presence of the palladium catalyst.
Gluconic Acid Formula
Gluconic acid is an organic compound that is also termed Dextronic acid and is one of the 16 stereoisomers of 2,3,4,5,6-pentahydroxyhexanoic acid. Its IUPAC name is D-Gluconic acid, and it has a molecular formula of C6H12O7. It is a non-toxic compound that can be found in honey, wine, fruits, etc. It appears as a colourless to light yellow, clear, syrupy liquid and has a mild acid taste. It is very soluble in water, slightly soluble in alcohol, and insoluble in ether and many other organic solvents. It was first discovered by Hlasiwetz and Habermann in 1870, through the chemical oxidation of glucose. In the presence of the cyclic ester glucono-delta-lactone, gluconic acid exists in equilibrium in an aqueous solution. The salts of gluconic acid are called gluconates, where a gluconate ion is formed by gluconic acid in an aqueous solution at neutral pH. Gluconic acid, gluconate salts, and gluconate esters are abundant in nature as they can be produced by the oxidation of glucose. In an alkaline solution, the gluconate anion chelates Ca2+, Fe2+, Al3+, and other metals, including lanthanides and actinides.