PROCEDE D'HYDRODIMERISATION ELECTROLYTIQUE

In an electrolytic hydrodimerisation process for olefinic cpds. in which a heavy metal passes into the aqueous medium during electrolysis in quantity greater than that which is soluble in the initial liquid; sufficient sequestrant is added during hydrolysis to maintain the heavy metal substantially in soln. in the electrolysis zone and to maintain a stable dissolved heavy metal concn., pref. sufficient sequestrant is added such that the undissolved heavy metal is below 2 millimols/1. Particularly the heavy metal comes from the anode and the olefines are of formula (R)2C=CR-X where X is -CN, -CONR, or COOR' where R is H or R' which is 2-4C alkyl. Pref. acrylonitrile is an aq. medium contg. quat. ammonium ions and a conducting salt is used; 100-2, 500 ppm of heavy metal is maintained in soln. using an iron or steel anode, a cadmium cathode and an aminocarboxylic acid sequestrant specif. a salt of ethylenediamine tetra-acetic acid or N-hydroxyethyl-ethylenediamine-tri-acetic acid. Previous methods have not been effective over long periods in preventing heavy metal deposition which results in reduced efficiency by hydrogen formation.