There are various methods for the preparation of carboxylic acids. For example, oxidation of primary alcohols or aldehydes using strong oxidizing agents results in a carboxylic acid. Aldehydes can also be oxidized in the presence of mild oxidizing agents.

Alkyl benzenes, bearing at least one benzylic hydrogen, can be oxidized using KMnO₄ or Na₂Cr₂O₇ to yield benzoic acid exclusively. The reaction is carried out under vigorous conditions such as heat and high oxidant concentration.

When internal alkynes are treated with concentrated KMnO₄ or, upon ozonolysis, undergo oxidative cleavage to yield carboxylic acids. In comparison, terminal alkynes release CO₂ along with the generation of the acid.