Benzoic Acid Synthesis

Introduction Toluene, according to the International Union of Pure and Applied Chemistry system (IUPAC) – methylbenzene, is most commonly used to synthesize benzoic acid. The importance of benzoic acid in modern world is due to its uses: the acid and its salts are used as preservatives in food: benzoic acid is globally known as E210 and sodium benzoate as E211. The benzoic acid and its precursors are also used in pharmacy and hygiene products : the shampoo and shower gel that I am using all contain sodium benzoate. With its increasing production I was curious to explore the synthesis methods for benzoic acid and try it in the laboratory. Interestingly, in the U.S. the production of benzoic acid exceeds over 139 tons per year and there are

However, potassium permanganate was readily available at the school laboratory as well as it proposed less dangers compared to the other oxidizing agents for the experiment. Additionally, the description and explanation of this experiment allowed me to have a guideline how to perform the synthesis. An unknown aromatic starting material was chosen as toluene and no sodium hydroxide was used. After doing a preliminary research, the alkali was not a necessity for the synthesis. I expected the synthesis yield to be at least lower than 50% as it is not an industrial method but was interested to get the exact result from the calculations. Thus, my research question claims to be how efficient the toluene oxidation by potassium permanganate is? After the practical efficiency of the reaction was obtained, the theoretical comparison with industrial oxidizers and alkyl benzenes was done. Also, the question whether this particular synthesis method should be encouraged for green chemistry method is also

The mixture is allowed to reach its boiling temperature 110.6°C (383.75K) and mixed by magnetic-stirring bar from 3 to 4 hours. The first step results in intermediate potassium benzoate (C6H5COOK) and alkaline medium potassium hydroxide formed from alkaline potassium permanganate. When potassium permanganate dissociates, it forms potassium ions K+ and permanganate ions MnO_4^- of purple colour. This K+ ion reacts with water in the mixture and forms the basic