Previous work on the electrolysis of acrylonitrile in aqueous quaternary ammonium salts under mildly alkaline conditions has been extended into the region of high acrylonitrile- water ratios. At very low water concentrations acetone-soluble, relatively low-melting polyacrylonitriles of average mol. wt. 600-1300 are formed. From electrolyses of catholytes of intermediate (but still low) water content there were isolated an acrylonitrile hydro trimer ...