OXALIC ACID - CHINA/ INDIA
CAS number: 144-62-7
EC Number: 205-634-3
UN number: 3261
MeSH: + Oxalic acid
Cheb: 16 995
RTECS number: RO2450000
ATCvet code: QP53AG03
Beilstein Reference: 385 686
Gmelin Reference: 2208
Molecular formula: C2H2O4
Molar mass: 90.03 g mol-1 (anhydrous) 126.07 g mol-1 (dihydrate)
Appearance: White crystals
Density: 1.90 g cm-3 (anhydrous) 1.653g cm-3 (dihydrate)
Melting point: 189-191 ° C, 462 to 464 N, 372 376 ° F (101.5 ° C (214.7 ° C) dihydrate)
Solubility in water: 3.14 g / 100ml (25 ° C)
Solubility: 7.23 g / 100 mL in ethanol (15 ° C) 1.4 g / 100 ml in diethyl ether (15 ° C)
Acid (pKa): 1.25, 4.14
Flash point: 166 ° C (331 ° F)
Oxalic acid, whose chemical formula is C2H2O4, is one of the most well-known organic acids, a weakly acidic, odorless crystalline or powdery plant-based chemical. It consists only of two interconnected carboxyl radicals. Water and polar organic solvents in the event is resolved. The oxalic used in beekeeping is a form of Dihydrate in which two molecules of water have been added. Commercially it is usually sold in the form of dihydrate, ie H2C2O4.2H2O, as it has the ability to absorb moisture from the bed. Calcium oxalate is the most common salt form.
Production and Reactions
Oxalic acid is obtained commercially from the sodium formate (H-COONa). For this purpose, the sodium formate is rapidly heated to 360 ° C with sodium hydroxide; According to the reaction, the sodium salt of oxalic acid is obtained. This is followed by calcium oxalate with the addition of lime milk, followed by sulfuric acid treatment to give oxalic acid.
Dihydrate form is used in this sector as titration standard in alkalimetri and manganometry. Calcium is used in the quantitative analysis and the use of rare earth metals in the separation of other types of use.
We know that it is also used in the Varroa struggle in organic and conventional beekeeping.
In the pharmaceutical industry; used as purification agent.
It is used to remove calcium ions from the water in the waste water treatment industry.
Unlike other carboxylic acids other than formic acid, oxalic acid can be easily amplified. Because of this feature, whitening, rust and ink removal is used in such operations.