The Synthesis And Investigation In The Copolymerization Of PO/CO₂ As Catalysts Of Schiff Transition-Metal Complexes

The chemical utilization of carbon dioxide makes great sense in both utilizeing carbon dioxide resource and environmental issue. Since Inoue et al. firstly discovered that aliphatic polycatbonate could be synthesized via the copolymerization of CO2 and cyclic ethers in 1969, more and more scientist had worked in this field. In this paper, a series of SalenCoX complexes have been synthesized and applied them in the copolymerization of carbon dioxide and propylene oxide as catalysts. The results and structure of copolymer affected by catalysts and reaction conditions were investigated.1. 8 kinds of salicylaldehyde derivatives had been synthesized and their structures were characterized by 1H-NMR spectroscopy and melting point testing.2. 6 kinds of Salen ligands and 10 kinds of complexes had been synthesized,all of the ligands were characterized by 1H-NMR, 13C-NMR, IR, MS and UV-Vis and part of the complexes were characterized by IR, cyclic voltammetry, MS and elemental analysis, the H2L2, H2L6 and all of the metal-Salen complexes were first reported.3. The catalysts we synthesized were employed in the copolymerization of CO2 and propylene oxide as catalysts for the first time. The effect on copolymerization of CO2 and propylene oxide by catalysts, reaction time, the pressure of CO2 and the ratio of monomer/Co were investigated.4. The copolymer were characterized by 1H-NMR, 13C-NMR, IR and GPC. The results show that the copolymer have a good selectivity for the incopration of carbon dioxide into polymer (carbonate linkages >96% selectivity at least) and a good regioselectivity for the Head-to-Tail sequence of linkage (H-T% linkages reach to 86% best).