Citric acid is a weak organic acid that has the molecular formula C6H8O7. It decomposes with loss of carbon dioxide above about 175 °C. More than two million tons of citric acid are manufactured every year. Citric acid can be obtained as an anhydrous form or as a monohydrate.
About Citric acid in brief
Citric acid is a weak organic acid that has the molecular formula C6H8O7. It occurs naturally in citrus fruits. More than two million tons of citric acid are manufactured every year. It is used widely as an acidifier, as a flavoring and a chelating agent. Citric acid can be obtained as an anhydrous form or as a monohydrate. It decomposes with loss of carbon dioxide above about 175 °C. The pKa of the hydroxyl group has been found, by means of spectroscopy, to be 13C to 14. On the other hand, the pH of a citrate solution of 1MmM will be about 3.5. The SSCX hybridization is an example of a common use in common use. The pH of the citrate ion and monohydrogen ion are about 2.5 to 4.5 in biological systems around pH 7, the two species present are citrate ions and monoHydrogen ion. The citrate anion is written as C3H5O3−7 or C4H5 O3−3. It can constitute as much as 8% of the dry weight of lemons and limes. It also dissolves in absolute ethanol at 15 °C, and can be converted to the anHydrous form at about 78 °C. It was first isolated in 1784 by the chemist Carl Wilhelm Scheele, who crystallized it from lemon juice.
In 1917, American food chemist James Currie discovered certain strains of the mold Aspergillus niger could be efficientcitric acid producers. The source of sugar is corn steep liquor, molasses, hydrolyzed corn starch, or other inexpensive, sugary solution. After the mold is filtered out of the resulting solution, citric Acid is isolated by precipitating it with calcium hydroxide to yield calcium citrate salt, from which it is regenerated by treatment with sulfuric acid, as in the direct extraction from citrus fruit juice. Global production was in excess of 2,000,000 tons in 2018. More than 50% of this volume was produced in China. Some 20% was used as a acidity regulator in beverages, some 20% in other food applications, 20% for detergent applications, and 10% for applications other than food, such as cosmetics, pharmaceuticals, and in the chemical industry. In 1977, a patent was granted to Lever Brothers for the chemical synthesis of citic acid starting from aconitic or isocitratealloisocitrates calcium salts under high pressure conditions.