Electrosyntheses of α ‐Hydroxycarboxylic Acids from Carbon Dioxide and Aromatic Ketones Using Nickel as the Cathode

Abstract

AbstractWith Ni as the cathode and Al as the anode, aromatic ketones (acetophenone, benzophenone, 6‐methoxy‐2‐acetonaphthone, 4‐methylacetophenone and 4‐methoxyacetophenone) could be successfully electrocarboxylated with CO2 (4 MPa) in an undivided cell containing n‐Bu4NBr‐DMF electrolyte at a constant current under room temperature, affording the corresponding α‐hydroxycarboxylic acids in good to excellent yields (56%–90%). The experimental results showed that the yields of the target products were strongly dependent on the nature of cathode materials and aromatic ketones as well as electrolytic conditions (such as electricity, substrate concentrations, conducting salts and solvents, CO2 pressure). In addition, it was found that the presence of protic agent such as water would lead to the increase of pinacol byproducts. The reaction mechanism was briefly discussed by CV experiments.