Highly active, recyclable catalyst for the manufacture of viscous, low molecular weight, CO–ethene–propene-based polyketone, base component for a new class of resins

A highly active, recyclable homogeneous palladium(II) catalyst is described for the manufacture of viscous, low molecular weight CO–ethene–propene-based polyketone (CariliteOligomer), used for the manufacture of a new class of resins (CariliteResins). The catalyst is composed of palladium acetate, and a sulfonated diphosphine ligand, bdompp-S (1,3-bis(di-(2-methoxy, 5-sulfonatophenyl)phosphino)propane). In comparison with its non-sulfonated counterpart this catalyst not only exhibits a much more favourable partitioning coefficient in liquid–liquid separation of the polyketone product and solvent, but it also exhibits an approximately 2.5 times higher catalytic activity (up to 11.2 kg PK (g Pd)−1 h−1) in the manufacture of PK-PE-30 (polyketone terpolymer built up of CO, ethene and propene in a molar ratio of 100:30:70). A variety of salts were found to exert a positive influence on the activity of the catalyst. Possible origins of this ‘salt-effect’ are briefly discussed. The bdompp-S ligand was synthesised by sulfonation of bdompp using either a boric acid–oleum mixture or sulfuric acid as the sulfonation reagent. The product was isolated either as sodium-salt (bdompp-S[Na]4·nNa2SO4), by extraction with methanol after neutralisation, or, in acidic, hydrated form (bdompp-S[H]4·nH2O), via a new and highly efficient procedure, i.e. cooling the reaction mixture after dilution with water. The X-ray crystal structure of bdompp-S[H]4·nH2O is discussed.