Etanodioico

Etanodioico, more commonly known as oxalic acid, is a simple organic dicarboxylic acid with the chemical formula C2H2O4. It exists as colorless, crystalline solid that is highly soluble in water and exhibits strong acidity in its two dissociable carboxyl groups. The compound forms a variety of salts, collectively called oxalates, with calcium oxalate being particularly well known for its low solubility in water.

Chemically, etanodioico features two carboxyl groups attached to a two-carbon backbone. Its dissociation occurs in two steps, with the first pKa around 1.2–1.3 and the second around 4.3, making it a relatively strong diprotic acid among carboxylic acids. As a reducing agent, it can participate in redox reactions, including the reduction of permanganate. On heating, oxalic acid decomposes and releases carbon monoxide and carbon dioxide.

Natural occurrence and production are linked to both plant metabolism and industrial processes. Oxalic acid occurs in many plants, such as spinach and rhubarb, and is involved in metabolic pathways producing oxalate. Industrially, it is produced by oxidation of glycolic acid or ethylene glycol, using oxidants such as nitric acid or air in catalytic processes.

Applications of etanodioico include use as a bleaching agent and cleaning agent, particularly in wood bleaching and rust removal. It is also employed in analysis as a standard reagent for precipitation reactions, in paper and boiler water conditioning as a sequestrant, and in various textile and leather processes. Safety considerations are important: oxalic acid is corrosive and toxic if ingested, capable of forming insoluble calcium oxalate crystals in the body, and exposure should be minimized.