C6H5F

Fluorobenzene, with the chemical formula C6H5F, is an organofluorine compound that represents benzene in which one hydrogen has been replaced by fluorine. It is a colorless to pale yellow liquid at room temperature with a boiling point around 85°C. It is relatively volatile and insoluble in water, but miscible with many organic solvents.

Synthesis and occurrence: Fluorobenzene is prepared by direct fluorination of benzene using fluorinating agents such as elemental fluorine in the presence of catalysts (for example iron(III) fluoride) at elevated temperatures, or by halogen exchange from chlorobenzene with hydrogen fluoride under catalytic conditions. It can also arise as a byproduct in other fluorination processes.

Chemical properties: The fluorine substituent withdraws electron density, making fluorobenzene less reactive toward electrophilic substitution than benzene, though it still participates in nitration, sulfonation, and further halogenation under suitable conditions. The carbon–fluorine bond is strong and fluorobenzene can undergo nucleophilic substitution only under activated or specialised conditions.

Uses: It is used as a solvent and as a versatile building block in the synthesis of pharmaceuticals, agrochemicals, and organic materials. In medicinal chemistry, it is employed to introduce fluorine into molecules, influencing metabolic stability and bioavailability.

Safety: Fluorobenzene is flammable and its vapors can be harmful if inhaled. It can irritate skin, eyes, and the respiratory tract. It should be handled with proper ventilation and protective equipment.