| abstract |
New bidentate ligands of the general formula (I) are described. Formula (I): R represents a hydrocarbyl aromatic structure. The substituent Y x on the aromatic structure has a total x = 1 to n ΣtY x of atoms other than hydrogen so that x = 1 to n ΣtY x is ≧ 4, where n is the substituent Y x is the total number of x , and tY x represents the total number of atoms other than hydrogen in the specific substituent Y x . Group, X 1, X 2, X 3 and X 4 via a tertiary carbon atom for each atom Q 1 or Q 2 bound to Q 1 or Q 2, Q 1 and Q 2 are independently phosphorus Represents arsenic or antimony. A catalyst system and a process for the carbonylation of ethylenically unsaturated compounds utilizing the catalyst system are also described. |