Patent attributes
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.
