AbstractThe reduction of acrylonitrile at mercury electrodes has been studied both polarographically and coulometrically at controlled potential. The half‐wave potential is about 1.6 v. versus a mercury pool both for pure acrylonitrile and for acrylonitrile in dimethylformamide, in the presence and absence of water. As long as water is present the diffusion current is directely proportional to the concentration of acrylonitrile, at least up to 0.2 mg./ml. In the absence of water, reduction of acrylonitrile in dimethylformamide at this potential leads to condensation of reactions initiated by the carbanion. The diffusion current is no longer proportional to the concentration. Comparison of electrolytic‐ and sodium‐reduction products of acrylonitrile gives information about the mechanisms of these reductions and the role of water in the polarographic analysis. A new yellow sodium‐reduction polymer of acrylonitrile is described, and data on the ultraviolet and infrared spectra are presented.