Process for preparing nitrile compounds from ethylenically unsaturated compounds

#The present invention concerns a process for hydrocyanating ethylenically unsaturated organic compounds to compounds containing at least one nitrile function.

#It relates more particularly to the hydrocyanation of diolefins such as butadiene or of substituted olefins such as alkenenitriles, for instance pentenenitriles. The hydrocyanation of butadiene to pentenenitriles is an important reaction which has been implemented industrially for a number of years, particularly in the process for synthesizing adiponitrile, a major chemical intermediate which allows access in particular to the monomers of numerous polymers, foremost among which are the polyamides.

#French patent 1 599 761 describes a process for preparing nitrites by addition of hydrocyanic acid with organic compounds having at least one ethylenic double bond, in the presence of a nickel catalyst and a triaryl phosphite. This reaction may be conducted in the presence or absence of a solvent.

#The general procedure used is as follows:

#Under an argon atmosphere a 60 ml Schott glass tube equipped with a septum stopper is charged in succession with the ligand (2.5 eq), 1.21 g (15 mmol; 30 eq) of anhydrous 3PN, 138 mg (0.5 mmol; 1 eq) of Ni(cod)2 and the Lewis acid (0.5 mmol; 1 eq).

#The mixture is taken to 70° C. with stirring. Acetone cyanohydrin is injected into the reaction mixture by means of a syringe driver at a rate of 0.45 ml per hour. After 3 hours of injection the syringe driver is stopped. The mixture is cooled to ambient temperature, diluted with acetone and analysed by gas chromatography.