A method of reducing the formation of an impurity in a terephthalic acid (TPA) production process includes: combining in a reactor, a catalyst, a mixture comprising the impurity and the TPA, and a compound comprising an active carbon atom; reacting the impurity with the compound in the presence of the catalyst by a condensation-dehydration reaction process comprising a nucleophilic addition of the active carbon atom of the compound to a carbonyl group of the impurity to form an intermediate followed by a dehydration reaction of the intermediate to form a product mixture comprising a water, the TPA, and an alkene; and recovering the product mixture from the reactor.