Abstract:
Fluorobenzene is an important fluorine-containing organic intermediate, widely used in the synthesis of pesticides/pharmaceuticals such as trifluoperidol, trifluoperazine, flufenoxuron, and flusilazole, as well as in the production of liquid crystals and the monomers for high-performance polymer materials. In recent years, with the rapid development of industries such as agrochemicals, pharmaceuticals, and electronic information, the demand for fluorobenzene has shown a significant upward trend. This review summarizes the synthetic methods of fluorobenzene reported to date, categorizing them into six types of reactions: Balz-Schiemann reaction, nucleophilic fluorination, electrophilic fluorination, electrochemical fluorination, and oxyfluorination. The research progress of each synthetic approach is systematically reviewed; the industrial synthesis of fluorobenzene is still dominated by the Balz-Schieman method, but the poor intrinsic safety of the process and the problem of many three wastes have not yet been effectively solved; and other emerging methods, such as nucleophilic fluorination and electrophilic fluorination, suffer from the problems of low activity, high cost of fluorination reagents and poor selectivity. Furthermore, we also analyze the key catalysts that influence the efficiency of these synthesis reactions, focusing on their structures, compositions, and preparation methods. The existing gas-phase fluorination catalyst system can hardly meet the demand of fluorobenzene synthesis reaction, and the liquid-phase fluorination and phase-transfer catalysts need to be further optimised due to their high cost and difficulty in recycling. Finally, the future development of fluorobenzene synthesis should focus on microreactor technology, new fluorination reagents and efficient fluorination catalysts.