Karboksilaatti

Karboksilaatti, or carboxylate, is the term for salts of carboxylic acids. They contain the carboxylate anion, R-COO−, paired with a countercation such as Na+, K+, or NH4+. They are the conjugate bases of carboxylic acids, forming when the acidic proton is replaced by a metal or ammonium ion.

In aqueous solutions, carboxylates behave as weak bases because their parent carboxylic acids are weak. The specific properties depend on the R group; small, alkyl carboxylates are often soluble in water with appropriate counterions, while longer chains reduce solubility. The carboxylate group is resonance-stabilized, giving high stability to the anion. Carboxylates commonly act as ligands in coordination chemistry, binding through the two oxygens to metal centers. Common examples include sodium acetate, potassium formate, and potassium benzoate.

Carboxylates are produced by neutralizing carboxylic acids with bases such as sodium hydroxide or potassium hydroxide. They also form in metabolism and fermentation processes and are widely manufactured for industrial and consumer use. In food and pharmaceuticals, salts like sodium benzoate and potassium sorbate serve as preservatives or buffering agents.

Beyond additives, carboxylates are important in organic synthesis and catalysis, in leather tanning, textile processing, and as reagents in esterifications and transesterifications. In biology, many metabolic pathways involve carboxylate intermediates.