| The DMC catalyst based on Zn3[Co(CN)6]2 (ZHCC) was employed successfully in copolymerization of propylene oxide (PO) and CO2, the highest molar fraction of CO2 in PO- CO2 copolymer(f CO2) was 0.32, at the same time, propylene carbonate(PC) was also obtained as by-product. The efficiency of catalyst was up to 2,000 g copolymer/g ZHCC, which was about 20 times and 50 times over efficiency of Fe-Zn DMC, zinc carboxylate and ZnEt2-multiprotic compounds respectively. The effect of reaction conditions on efficiency and composition of products was investigated. The results revealed that catalytic efficiency increased with ascending temperature and descending pressure. The efficiency demonstrated in stepwise feed was lower than that in one-pot feed. The f CO2 was at the range of 0.1-0.32, and it ascended with increased pressure and decreased temperature. The content of PC varied between 10~30% under different reaction conditions. The results showed that higher temperature and pressure were favored for production of PC.The effect of preparative method on catalytic efficiency was systematically studied. The results showed that catalyst exhibited different efficiency when various organic solvents were employed in preparation of catalyst, the catalyst exhibited highest efficiency when tert-butyl alcohol was used. These catalysts showed no difference on f CO2- Lewis acid zinc halide was testified as important composition when various zinc salts were used in preparation of catalysts. When other halide salts were used combining with zinc chloride in preparation, the efficiency of resulted catalysts decreased sharply except for AlCl3, SnCl2.When the catalyst was used in copolymerization of cyclohexene oxide (CHO) and CO2 , the nearly alternative copolymer (f CO2=0.45~0.47) with Mw = 40,000~50,000 was obtained. The efficiency for CHO- CO2 copolymerization was up to 10,000 copolymer/ g ZHCC at concentration of 120 ppm. To sum up, the catalyst exhibited highest efficiency for epoxide-CO2 copolymerization among contemporary catalysts, whose efficiency was about 20-50 times over diethyl zinc and zinc carboxylate catalyst, tenfold over efficiency of zinc (β-diiminates) complex. It was highest effective catalyst reported by literatures up to now.The effect on reaction temperature, pressure, catalyst concentration on f CO2 of copolymer, and effect of preparative method of catalyst on efficiency were thoroughly investigated. The results showed that higher pressure and lower temperature were favored for incorporation of CO2. The f CO2 can reach 0.408 even under lower pressure as 0.6MPa. Catalyst concentration and catalysts prepared in the presence of different organic solvents did not impact on f CO2 of copolymer. The fully alternative copolymer could not obtained even under optimum condition (the highest f CO2 was 0.47). The catalyst efficiency increased with ascending temperature and pressure.The DMC catalyst with hybrid ligand (Zn3[Co(CN)5L]2, L= Cl-, Br-, I-, NO2 -, N3-respectively) was prepared and employed in copolymerization of PO and CO2.The results showed that the catalytic trait changed significantly after tiny modification, they exhibited inferior efficiency compared with catalyst based on ZHCC, the descending order of efficiency for ligand was N3-> Br- NO2-> I-> Cl-, the descending order of f CO2 was Na3- Br-> NO2- I~> Cl-. The DMC containing I- or Cl- ligand was not a suitable catalyst for copolymerization of epoxide and carbon dioxide yet.The DMC catalyst with other central metal except for Co(III), which was Cr(III), Mo(IV), Mn(III), Fe(III),Fe(II), Ni(II), Cd( II),respectively was prepared and used as catalyst for copolymerization of PO and CO2. They exhibited lower efficiency than catalyst based on ZHCC. The descending order for efficiency was Ni(II)> Fe(III) > Fe(II) > Cr(III) >Mo(IV) Mn(III) Cd(II). Only the first two kinds of catalysts were suitable as catalyst for copolymerization.The DMC catalyst based on ZHCC was firstly prepared by precipitation transformation instead of solution precipitating method, in which insolub...
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