A PROCESS FOR THE PREPARATION OF COPOLYMERS

A process for the preparation of a copolymer of carbon monoxide with an olefinically unsaturated compound, which process comprises suspending a copolymer of carbon monoxide with an olefinically unsaturated compound in a liquid diluent in which the copolymer to be prepared forms a suspension and subsequently contacting the monomers in the suspension so obtained with a catalyst composition which is soluble in the diluent and which is based on a Group VIII metal and a bidentate ligand of the general formula R5R6M1-R-M2R7R8, wherein M1 and M2 independently represent a phosphorus, nitrogen, arsenic or antimony atom, R5, R6, R7 and R8 independently represent an optionally polar substituted hydrocarbyl group, on the understanding that at least one of R5, R6, R7 and R8 represents a polar substituted hydrocarbyl group, and R represents a bivalent organic bridging group containing at least one carbon atom in the bridge, and which catalyst composition is used in such a quantity that in the polymerization mixture more than 0.1 mmoles of the Group VIII metal is present per litre of liquid phase.