| abstract |
1. Novel catalyst compositions characterized in that they are based upon:n a) a palladium compound, b) a quaternary phosphonium salt of an acid with a pKa of less than 2, with the proviso that the acid is not a hydrohalogenic acid or a mixture of such a salt and acid, and c) either a phosphorus bidentate ligand of the general formula R¹R²-P-R-P-R³R⁴, wherein R¹, R², R³ and R⁴ are hydrocarbyl groups which may or may not be substituted with polar groups and R represents a bivalent organic bridging group containing at least two carbon atoms in the bridge, or a nitrogen bidentate ligand of the general formulan wherein X and Y are similar or dissimilar bridging groups, each containing three or four atoms in the bridge at least two of which are carbon atoms. |