Carboxylic Acids

  • Carboxylic acids are organic compounds that contain a carboxyl group (-COOH), which is a functional group consisting of a carbonyl (C=O) and a hydroxyl (O-H) group on the same carbon atom.
  • The general formula for carboxylic acids is CnH2n+1COOH. The simplest carboxylic acid is Methanoic (Formic) Acid (HCOOH).
  • They are weak acids due to the presence of the acidic hydroxyl group. In water, they partially ionise to produce hydronium ions (H3O+) and carboxylate ions (RCOO-).
  • Carboxylic acids exhibit hydrogen bonding, due to the polar nature of the carbonyl and hydroxyl groups in the carboxyl group. This results in them having higher boiling points compared to similar sized alcohols or aldehydes.
  • They react in typical acid reactions, meaning they can neutralise bases to form salts and water, and they can react with carbonates to produce carbon dioxide, a salt and water.
  • Due to their acidic nature, they can form esters when they undergo condensation reactions with alcohols in the presence of an acid catalyst. This ascertainment is known as esterification.
  • Naming carboxylic acids follows the IUPAC nomenclature by replacing the -e at the end of the corresponding alkane with -oic acid. For example, ethane becomes ethanoic acid.
  • Organic compounds can be oxidised to carboxylic acids. Primary alcohols are oxidised to aldehydes and then further oxidised to carboxylic acids. Aldehydes can also be directly oxidised to carboxylic acids.
  • The derived carboxylate salts are named by changing the -ic acid ending of the parent carboxylic acid to -ate. For instance, the sodium salt of methanoic acid is sodium methanoate.
  • Dicarboxylic acids are carboxylic acids that contain two carboxyl groups and their chemical properties are similar to those of monofunctional carboxylic acids. An example of a dicarboxylic acid is ethanedioic acid (oxalic acid) with the formula (COOH)2.
  • You will encounter carboxylic acids in diverse contexts in the chemical industry, including in the manufacture of pharmaceuticals, dyes, plastics and detergents.