Electrocarboxylation of Carbon Dioxide with Polycyclic Aromatic Hydrocarbons Using Ni as the Cathode

Using Ni cathode and Al sacrificial anode, the electrocarboxylation of polycyclic aromatic hydrocarbons (naphthalene, 5-methylnaphthalene, anthracene, phenanthrene and 1H-indene) with carbon dioxide (4 MPa) could be successfully performed in an undivided cell containing n-Bu4NBr-DMF supporting electrolyte with a constant current at room temperature, affording the corresponding trans-dicarboxylic acids in good to excellent yields (62% -90%). Among the examined cathode materials (Ni, Pt, Ag, Cu and Zn), Ni and Pt cathodes exhibited a good catalytic activity for the electrocarboxylations. In addition, the experimental results indicated that electrolytic conditions (conducting salts, electricity, CO2 pressure and temperature) could also affect the result of the electrocarboxylation. According to the results of the electrocarboxylations and CV (cyclic voltammetry), a possible electrochemical reaction mechanism was also proposed.