What is Carboxylic Acid?

Carboxylic acids are organic compounds that contain a (C=O)OH group attached to an R group (where R refers to the remaining part of the molecule).

The COOH group is commonly referred to as a carboxyl group. Carboxylic acids can generally be expressed via the formula R-COOH. Carboxylic acids have a polar nature. They can also participate in hydrogen bonding owing to their hydrogen bond accepting nature of the C=O group and the hydrogen bond donating nature of the O-H bond. They generally have higher boiling points when compared to water and tend to form stable dimers.

Carboxylic acids play an important role in the production of pharmaceuticals, food additives, solvents, and polymers. Acetic acid, adipic acid, and citric acid are a few carboxylic acids which are extremely useful industrially.

Preparation of Carboxylic Acids

Primary alcohols are readily oxidized to carboxylic acids with common oxidizing agents such as potassium permanganate in neutral acidic or alkaline media or by potassium dichromate and chromium trioxide in acidic media.

RCH₂OH → RCOOH

CH₃(CH₂)₈CH₂OH → CH₃(CH₂)₈COOH

Properties of Carboxylic Acids

• Carboxylic acids are polar compounds and can extensively enter into hydrogen bonding.
• Aromatic carboxylic acids are practically insoluble in cold water. All carboxylic acids are soluble in organic solvents like ether, alcohol, benzene, etc.
• Among organic acids, carboxylic acids are the most acidic, but they are less acidic than the mineral acids, namely nitric acid and sulphuric acid.

Nomenclature of Carboxylic Acids

• Carboxylic acids are named by adding an “-oic acid” suffix to their parent chain. For example, C₃H₇COOH is called butanoic acid.
• Even if there are other substituents present, the carboxylic acid can be considered at the first position of the parent chain, as seen in the name for 3-Chloropropanoic acid.
• The COOH group can also be called “carboxy” and used as a substituent in the name of the parent structure. For example, 2-Furoic acid is commonly referred to as 2-carboxy furan.