The formation of benzoic acid is done through the nucleophilic addition of a Grignard reagent with carbon dioxide. Grignard reagents contain a polarized carbon-magnesium bond, which allows the compound to be a good nucleophile and a strong base. Since the compound is a good nucleophile, it can donate electrons to the partially positive charged carbon of a carbonyl in a nucleophilic addition. However, because Grignard reagents are also strong bases, any compound with acidic hydrogen can destroy the reagent by forming a new carbon-hydrogen bond. Therefore, anhydrous conditions must be used to prevent the decomposition of the reagent. The Grignard reagent for this experiment, phenylmagnesium bromide, is synthesized through a reaction of bromobenzene with magnesium turnings in diethyl ether. The reagent is then reacted with carbon dioxide to yield the bromomagnesium salt of benzoic acid. Hydrochloric acid is used to protonate the benzoate ion and dissolves magnesium salts. The organic and aqueous layers are separated with the aqueous layer containing the undesirable inorganic ions. The ether layer is extracted with several portions…show more content… However, such reactions with Grignard reagents do not occur in living systems. Thus, nucleophilic additions with Grignard reagents are only useful in lab and industrial settings to produce desired compounds. Benzoic acid itself is used as an antifungal agent, oral antiseptic, and as a food preservative (Medical Dictionary for the Health Professions and Nursing). Therefore, the synthesis of Benzoic Acid is extremely useful in the pharmaceutical industry and in food production. Conclusion Through the formation of a Grignard reagent and its reaction with solid carbon dioxide, benzoic acid was successfully synthesized. An acceptable percent yield and melting point were determined in order to validate the synthesis of the desired
