Electrochemical Investigation of Quinone Complexation by Lewis Acids in a Chloroaluminate Ionic Liquid

摘要

The electrochemical behavior of 9,10-anthraquinone (AQ) hasbeen investigated in the initially neutral aluminum chloride : 1-ethyl-3-methylimidazolium chloride ionic liquid. It has beenfound that AQ is characterized by a single irreversible redoxprocess in the neutral melt. Additions of AlCl_3 cause a positivepotential shift, first by the formation of two reversible redoxprocesses corresponding to AlCl_3 complexes of AQ under mildlyacidic conditions, and then by the appearance of a shiftedirreversible redox process in an acidic melt. HfCl4 additions causesimilar behavior, except that the reversible systems persist athigher Lewis acid levels than for AlCl_3. At the 11:1 Lewis acid:AQpoint, AQ is still soluble as an orange solution for AlCl_3 additions,but a yellow solid precipitates from a yellow (amber) solution forHfCl4 additions.