Preparation of zerovalent nickel complexes

Claim 1

In a process for the production of dinitriles by the addition of hydrogen cyanide to pentenenitriles in the presence of a zero-valent nickel-organophosphorus ligand containing catalyst promoted with an arylborane wherein the product fluid from said addition is contacted with a paraffin or cycloparaffin at a temperature of at least about 60° C. to form a primary light hydrocarbon extract phase containing catalyst values and a heavy dinitrile phase which phases are separated and wherein said catalyst is initially prepared by reacting elemental nickel with an organophosphorus compound, the improvement which comprises cooling said primary light extract phase sufficiently to form a secondary light phase and a secondary heavy phase, separating the secondary phases, removing substantially all of said hydrocarbon from the secondary light phase, and returning at least a portion of the residue thus obtained from the secondary light phase to the initial catalyst preparation to react with said elemental nickel.