Electrohydrodimerization process

In a continuous process for hydrodinergizing an olefinic compound having the formula R.sub.2 C.dbd.CR--X wherein --X is --CN, --CONR.sub.2 or --COOR;

• R is hydrogren or R' and R' is C.sub.1 --C.sub.4 alkyl, to form a dimerized product, which comprises electrolyzing in an undivided reaction cell an aqueous electrolyte having dissolved therein at least 0.1% by weight of the olefinic compound, at least 10.sup.-5 gram mol per liter of quaternary ammonium cations of a directive salt and at least 0.1% by weight of conductive salt, the aqueous electrolyte being in contact with a cathodic surface having a cathode potential sufficient for hydrodimerization of the olefinic compound with incidental formation of oxygen at the anodic surface, purging the aqueous electrolyte and recovering therefrom dimerized product, and reconstituting the aqueous electrolyte with the olefinic compound, fresh and recovered conductive salt and fresh and recovered quaternary ammonium salt, the improvement comprising charging to the electrolyte during electrolyzing an effective amount of a non-competing gas as herein defined whereby the concentration of oxygen in the aqueous electrolyte and at the cathodic surface is significantly lowered with a commensurate diminishing in corrosion of the cathodic surface.