Patent ID: 7687655

Claim:
A process for the production of dinitrile compounds by double hydrocyanation of a mixture of hydrocarbons containing at least one diolefin, which comprises: conducting a first hydrocyanation of the diolefins by reaction between the mixture of hydrocarbons and hydrocyanic acid in the presence of a catalytic system comprising a metal in the zero oxidation state and an organophosphorus ligand, separating the linear unsaturated nitriles from the reaction medium to form a first stream PN 1 , conducting, on this first stream PN 1 , a second hydrocyanation in the presence of hydrocyanic acid and a catalytic system comprising a metal in the zero oxidation state, an organophosphorus ligand and a Lewis acid, separating from the reaction medium, by distillation, the unconverted unsaturated nitriles to form a second stream PN 2 , separating, in the reaction medium, the dinitrile compounds formed from the catalytic system by a liquid/liquid extraction with a solvent to form a first stream of dinitriles DN 1 , jointly feeding the said streams PN 2 and DN 1 to a distillation stage to produce a top fraction F 1 comprising the said solvent and a bottom fraction Q 1 comprising the dinitrile and unsaturated nitrile compounds, feeding the bottom fraction Q 1 to a second distillation stage to separate the unsaturated nitriles, forming a top fraction F 2 , from the dinitriles, and forming a bottom fraction Q 2 , feeding the bottom fraction Q 2 to a third distillation stage to obtain a fraction comprising the linear dinitriles and a top fraction comprising the compounds with lower boiling points than that of the linear dinitriles.