Electrochemical Studies of the Fries Rearrangement in Ionic Liquids

The Fries rearrangement of phenyl benzoate has been investigated in the aluminum chloride: 1-ethyl-3-methylimidazolium chloride ( EMIC) system using both weakly acidic and neutral buffered melt compositions. The rearrangement products at 70o – 90oC were 2-hydroxybenzophenone ( 2-OHBP) and 4-hydroxybenzophenone ( 4-OHBP) in both systems. This reaction was also attempted in the ionic liquid EMIBF4, adding BF3 etherate as the Lewis acid. At a BF3: PB 3: 1 ratio, conversion to the PB: BF3 complex was not complete, but reaction at 85oC gave small amounts of 2-OHBP and 4-OHBP. Addition of AlCl3 to PB in EMIBF4 gave a more complete complexation of PB than did BF3 etherate