Deprotonation [carboxylate formation]

Deprotonation [carboxylate formation] Definition:


When treated with base, carboxylic acids form carboxylate salts.



Deprotonation [carboxylate formation] Explained:


Carboxylic acids exhibit both acidic and basic character: Deprotonation to carboxylate ions is relatively easy, but protonation more difficult. Carboxylic acids are weaker acids than inorganic (H2SO4, HCl) but when compared to most classes of organic compounds, they are relatively acidic. And as such, they readily react with Brønsted-Lowry bases to form carboxylate anions.

Treatment of a carboxylic acid with a strong base (NaOH, Na2CO3, NaHCO3) yields a carboxylate salt. Carboxylate salts are ionic and are more water-soluble than their corresponding carboxylic acids. When dissolved in water, an equilibrium is established in which the carboxylic acid and the carboxylate ion are both presents.



As we already know, a strong acid has a weak, stabilized the conjugate base. Deprotonation of a carboxylic acid forms a resonance-stabilized conjugate base, a carboxylate anion. In the resonance hybrid, the negative charge is delocalized over two oxygen atoms. Resonance stabilization of the conjugate base is important in determining acidity.