STUDIES OF A COBALT-PROMOTED ACRYLONITRILE COUPLING REACTION

Article abstract of DOI:10.1016/S0022-328X(00)86793-5

A stoichiometric cobalt-promoted acrylonitrile (AN) coupling reaction leading to adiponitrile (ADN) formation was reinvestigated.The active catalyst appears to involve cobalt(0) species.Cobalt hydride complexes are either inactive or give only low yields of ADN .Intermediate Co(AN)2 species can be reduced to give ADN using H2S or using H2 and Pt on C.Choice of ligand is a factor in determination of ADN yield, such yields decreasing in the order (CH3)2NCHO<*>PPh3>P(OPh)3>P(CH3)3>P(OC2H5)3.Formation of stoichiometric ADN yields from Co(N2)(PPh3)3 and AN indicate that co-promoters, such as ZnCl2 and CoCl2, are not required.Different ADN/c,t-1,4-dicyanobutene-1 product ratios, obtained by H2S treatment of Co(AN)2 species and a known complex, suggest that the intermediate Co(AN)2 species consist mainly of polymeric structures rather than monomeric metallacyclic complexes.