Abstract: The present invention relates to a process for the preparation of dinitriles by hydrocyanation of unsaturated nitrile compounds in the presence of a catalyst based on a metal element in the zero oxidation state and on organophosphorus ligands;the invention relates more particularly to a process for the recovery from the hydrocyanation medium of a catalyst for the hydrocyanation of unsaturated nitrites to dinitriles. It consists in controlling the concentration of unsaturated nitrites in the reaction medium resulting from the hydrocyanation reaction in order to obtain a concentration by weight of unsaturated nitrites of less than 20% in the said medium, and in then feeding the said medium to a stage of settling into two upper and lower phases. The lower phase comprises most of the catalytic system, while the upper phase is composed essentially of the dinitriles.

Abstract: Hydrocyanation reactions employing multidentate phosphite ligands and multidentate phosphite ligands are disclosed. The ligands have phenyl containing substituents attached to the ortho position of the terminal phenol group and/or attached to the ortho position of the bridging group. Catalyst compositions havng such ligands achieve 97% or greater distribution in hydrocyanation.

Abstract: A catalyst comprising at least one nickel(0) complex which comprises at least one mono-, bi- or multidentate phosphonite ligand of the formula I or salts and mixtures thereof, is prepared as described, and the catalysts are used to prepare mixtures of monoolefinic C5 mononitriles with nonconjugated C═C and C≡N bonds by catalytic hydrocyanation of butadiene or of a 1,3-butadiene-containing hydrocarbon mixture in the presence of a catalyst of this type.

Abstract: A process for resolving the racemates of phenylacetonitriles of the formula I ##STR1## where R.sup.1, R.sup.2, R.sup.3 and m have the meanings stated in the description is described. The process comprises dissolving the racemates I in a polar solvent, adding from 0.5 to 1.0 mol of optically active camphorsulfonic acid per mol of compound I, heating to 40.degree.-100.degree. C., allowing to cool and liberating the optically active phenylacetonitrile I from the salt obtained in this way.