Definition and Usage of Oxalic acid

Oxalic acid is mainly produced by the oxidation of carbohydrates or glucose in the presence of vanadium pentoxide using nitric acid or air. Various precursors can be used, including glycolic acid and ethylene glycol. A newer method requires oxidative carbonylation of alcohols to yield oxalic acid diesters.

4 ROH + 4 CO + 02 → 2 (CO2R) 2 + 2H20

Oxalic acid is one of the most well-known plant-derived organic acids. Oxalic acid, which is shown with the chemical formula COOH2, is found in nature as a calcium salt in the rhubarb plant, in the plant called sorrel as the sodium salt, and in the sap of some plants. Most plant sources contain this organic acid. Plants such as spinach, tomatoes, sorrel are in it. Because it is an acid, it can form a salt with an ion in the environment. Oxalic acid enters a biologically living system and body, where it forms salts with ions. Calcium oxalate, the most common salt, accumulates in the body, usually in the urinary system, especially in the kidneys, causing stone formation.

It is applied by mixing some oxalic acid into sugar syrup prepared with warm water and dripping on bees when the bee is in clusters and there are no closed brood at an outdoor temperature below 10 degrees. While the amount of sugar and water in the solution remains the same, the rate of oxalic acid may change according to the regional temperature. In other words, the rates vary for each region. It is recommended to apply this once a year. It is recommended not to apply this in colonies with less than three frames, due to the deterioration of the cluster temperature balance in colonies where bees are weak.

When heat is applied on oxalic acid dihydrate, it is a struggle with its sublimation property from solid state to gas state. In order to make these, there are evaporation apparatuses inside the hive, and oxalic acid is evaporated outside and sent into the hive through a pipe.

Usage areas

• The two aqueous dihydrates of oxalic acid are used in alkalimetry and manganometry, rarely in the separation of earth metals and in the quantitative analysis of calcium.
• C2H2O4 and its antimony salts are used as mordant in textile dyeing in the industry.
• It is used in the control of varroa in organic and conventional beekeeping in the food field. C2H2O4 used in the control of varroa in honey bees is oxalic acid hydrate with the chemical formula C2H2O4 – 2H2O. Instead of products containing heavy metals and residues, C2H2O4 hydrate from reliable places should be used.
• C2H2O4 main applications include cleaning or bleaching (iron complexing agent), especially to remove rust. Bar Keepers Friend is an example of a household cleaner that contains C2H2O4. Its usefulness in rust removal agents is that ferrous iron forms a stable, water-soluble salt with the ferrioxalate ion.
• C2H2O4 is an important reagent in lanthanide chemistry. Hydrated lanthanide oxalate occurs readily in strongly acidic solutions, in a densely crystallized, easily leached state, primarily free from contamination by non-lanthanide elements. Thermal decomposition of this oxalate yields oxides, the most marketed form of these elements.
• Evaporated C2H2O4 or a 3.2% solution of oxalic acid in sugar syrup is used by some beekeepers as a killer against parasitic insects.
• C2H2O4 is rubbed on the finished marble sculptures, sealing the surface and adding shine. C2H2O4 is also used to clean iron and manganese deposits from quartz crystals.
• C2H2O4 is used as a bleach for wood to remove black stains caused by water penetration.