Selectivity enhancement of aromatic halogenation reactions at the micellar interface: effect of highly ionic media

Abstract

Halogenation (iodination and bromination) of various aromatic compounds has been studied in micellar media in order to observe the effect on regioselectivity and conversion of the reaction. The addition of surfactant causes a change in the chemical shifts of the aromatic proton resonance of phenol which proves the orientation of the aromatic compound on the micellar surface. However, increase in ionic strength of the reaction media affects the selectivity of reaction by disturbing this spatial orientation of the aromatic compound in the micelle. Selectivity towards particular isomers is dependent on the concentration of the surfactant. In bromination of chlorobenzene (deactivated aromatic compound) enhancement in selectivity and conversion towards the para isomer has been observed.