Catalytic conversions in water: Part 14. The alternating copolymerization of ethene and CO catalyzed by water-soluble Pd catalysts

• Published in: Applied catalysis. A, General General, 2000-05, Vol.198 (1), p.5-11
• Main Authors: Verspui, Göran, Schanssema, Frank, Sheldon, Roger A
• Format: Article
• Language: English
• Subjects: Alternating copolymerization; Applied sciences; Aqueous phase catalysis; Carbon monoxide; Exact sciences and technology; Organic polymers; Palladium; Physicochemistry of polymers; Polymerization; Preparation, kinetics, thermodynamics, mechanism and catalysts; tppts
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/S0926-860X(00)00457-9

The alternating copolymerization of ethene and carbon monoxide proceeds efficiently in aqueous media in the presence of the water-soluble Pd/DPPPr-S/HOTs (DPPPr-S: C 3H 6-1,3-(P(C 6H 4- m-SO 3Na) 2) 2, HOTs: p-toluenesulfonic acid) catalyst system. A maximum catalyst activity of 7.7 kg copolymer (g Pd) −1 h −1 was observed at 90°C and 60 bar. The molecular weights of the copolymer samples increased with increasing pressure and decreasing temperature and ranged from M n=50.0 kg mol −1 (50°C, 40 bar) to M n=9.6 kg mol −1 (90°C, 40 bar). High reaction rates were observed when ethene/CO mixtures richer in CO (optimum at 64% v/v CO) were used, but the highest molecular weights were obtained when the ethene/CO ratio was 1.0. The water-soluble catalysts containing the water-soluble ligands 1,2-bis(di( m-sodiumsulfonatophenyl)phosphino)ethane (DPPEt-S), 1,4-bis(di( m-sodiumsulfonatophenyl)phosphino)butane (DPPBu-S) and ( s, s) 2,4-bis(di( m-sodiumsulfonatophenyl)phosphino)pentane (2,4-DPPPen-S), having a C 2H 4, n-C 4H 8 or 2,4- n-C 5H 10 bridge between the phosphorus atoms, respectively, were also tested in the copolymerization. Pd/DPPEt-S/HOTs was less stable, Pd/2,4-DPPPen-S/HOTs also exhibited a lower catalyst activity, while Pd/DPPBu-S/HOTs was more active compared to the catalyst system based on DPPPr-S. In all cases, the average molecular weights of the products were considerably lower compared to those of samples obtained with Pd/DPPPr-S/HOTs.