抄録
In recent years, ultrasonic effects on electrochemical processes have received much interest, since the processes are typical heterogeneous reactions in solid (electrode)-liquid (electrolytic solution) interfaces and should be greatly affected by mass transport of the substrate and intermediate species across the interface. In this work, the ultrasonic effect on the anodic cyanation of N-methylpyrrole was examined. The current efficiency for the anodic cyanation was greatly increased by ultrasonic irradiation. In addition, the product selectivity for the monocyanated product (1) formed by two-electrons oxidation along with dicyanated product (2) formed by four-electrons oxidation, was significantly increased under ultrasonic irradiation. This ultrasonic effect could be rationalized in terms of mass-transport promotion of N-methylpyrrole molecules to the anode surface from the bulk of the electrolytic solution by ultrasonic irradiation. Thus, the ultrasonic effect can be purposively applied to control the efficiency and selectivity in the anodic cyanation. Moreover, It was found that the current efficiency and product selectivity under ultrasonic irradiation was relatively high even if the NaCN concentration was decreased. This is desirable from an environmental viewpoint.
