Carbonylation catalyst system

摘要

Catalyst system comprising a palladium compound, an acid compound having a pKa>2 measured in water of 18° C. and an non-symmetrical bidentate phosphorous ligand according to:in which the -PR1R2 group is different from the -PR3R4 group and in which X is a divalent organic bridging group, in which the shortest direct link between the two phosphorous atoms in the bridging group X consists of a chain of 2-10 carbon atoms and optionally a sulphur or oxygen atom.