Ion-exchange membranes were initially used to separate the anode and cathode regions. In the latest advances in electrolysis cells, developed by Asahi, BASF, and UCB as well as by Mon- santo, no such mechanical separation is necessary. Instead, a finely divided two-phase emulsion is rapidly pumped through the cathode-anode system. The aqueous phase contains the con- ducting salt and a small amount of acrylonitrile (determined by its solubility), while the organic phase consists of acrylonitrile and adiponitrile. The loss of acrylonitrile in the aqueous phase by reaction is offset by the more facile transfer of acrylonitrile from the emulsified organic phase. Although graphite and magnetite (Fe,O,) can be used as cathode and anode, respec- tively, the most recent patents refer to an advantageous membrane-free procedure with a Cd cathode and Fe anode.