Oxalic acid, oxalic acid, one of the simplest organic dibasic acid. Short form HOOCCOOH structure. It is usually colorless, transparent crystal, harmful to human body, can raise the body's ph balance, affect a child's development, play an important role in the industrial, oxalate oxalate can derusting. Oxalic acid in in nature, often in the form of oxalate found in plants such as barberry, sheep hoof grass, sorrel and sorrel grass membrane, almost all plants contain oxalic acid salt.
Colorless monoclinic flake or prism crystals or white powder, oxidation, no smell, oxalate synthesis oxalic acid. 150 ~ 160 ℃ sublimation. In hot, dry air weathering. 1 g soluble in 7 ml and 2 ml water boiling water, 2.5 ml of ethanol and 1.8 ml, 100 ml boiling ethanol ether, 5.5 ml, glycerin, insoluble in benzene, chloroform and petroleum ether. 0.1 mol/L solution of the pH value of 1.3. Relative density (d18.54) 1.653. Melting point of 101 ~ 102 ℃, 187 ℃, no water). Low toxicity, median lethal dose (rabbit, percutaneous) 2000 mg/kg.
Oxalate in sublimation to the start of the 100 ℃, 100 ℃ when rapid sublimation, 157 ℃ when a large number of sublimation, and began to decompose. Can react with alkali, can occur esterification, acyl halide, amidation reaction. Can also occur reduction reaction, heat decarboxylation reaction. Anhydrous oxalic acid has the water absorbability. Oxalic acid can complex with many metals to form soluble in water. acid Oxalic acid is 10000 times stronger than acetic acid (acetic acid), is a strong acid in organic acids. The level of ionization constant Ka1 = 5.9 * 10 ^ 2, secondary ionization constant Ka2 = 6.4 * 10 ^ - 5. Connectivity with acid. Can occur with alkali neutralization, can make indicator discoloration, can and carbonate ions to emit carbon dioxide.