Ethylene/1-hexene was copolymerized by an unbridged zirconocene, (2-PhInd)2ZrCl2/MAO (methyl aluminoxane) at 0 °C and 50 °C respectively. High copolymerization activity and 1-hexene incorporation were observ...Ethylene/1-hexene was copolymerized by an unbridged zirconocene, (2-PhInd)2ZrCl2/MAO (methyl aluminoxane) at 0 °C and 50 °C respectively. High copolymerization activity and 1-hexene incorporation were observed at 0 °C, with the co- polymer formed having random sequence distribution and narrow molecular weight distribution. Ethylene polymerization at 50 °C showed high activity, but copolymerization at 50 °C showed much lower activity, which decreased sharply with increasing 1-hexene concentration in the monomer feed. Copolymer formed at 50 °C showed blocky sequence distribution and broad mo- lecular weight distribution. A mechanism model based on ligand rotation hindered by the propagation chain has been proposed to qualitatively explain the observed phenomena.展开更多
Copolymerization of ethylene/1-octene was carried out in toluene withvarious concentrations of comonomer in the feed using Et(Ind)_2ZrCl_2/MAO (methyl alu-minoxane) as catalyst. It was found that with the increase of ...Copolymerization of ethylene/1-octene was carried out in toluene withvarious concentrations of comonomer in the feed using Et(Ind)_2ZrCl_2/MAO (methyl alu-minoxane) as catalyst. It was found that with the increase of 1-octene concentration in thefeed the content of 1-octene in the copolymer increases, while the density, melting point,crystallinity and intrinsic viscosity of copolymer decrease. A copolymer with very lowdensity, containing 11.5 mol% of 1-octene (VLLDPE) can be produced with this catalystsystem. The effect of temperature and zirconium aluminum mole ratio of the catalyst onthe copolymerization was also investigated. The results of ^(13)C NMR determination of thecopolymer showed that the 1-octene units in the copolymer are principally isolated.展开更多
Complexes （R^1Cp）（R^2Ind）ZrCl2, the catalysts previously reported active for ethylene polymerization showed high activity in ethylene/1-hexene copolymerization and propylene polymerization in the presence of MAO. ...Complexes （R^1Cp）（R^2Ind）ZrCl2, the catalysts previously reported active for ethylene polymerization showed high activity in ethylene/1-hexene copolymerization and propylene polymerization in the presence of MAO. The content of 1-hexene in copolymers ranged from 1.2% to 3.2%. In propylene polymerization the complex 1 showed the highest activity, up to 1.2×10^6 g of polypropylene per mol of catalyst per hour. Based on the analysis of NMR spectral data, the relationships between complex structures and polymerization results were explored.展开更多
With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversi...With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversion,catalyst efficiency(CE),intrinsic viscosity([g])and insoluble content were studied.The copolymer was analyzed with Fourier transform-infrared(FTIR)and nuclear magnetic resonance(1H-NMR).Results showed that the optimal polymerization conditions were:He/Bt=0.25,temperature 40℃–50℃,Al/Ti=400–500,Ti/(Bt+He)=3x10-5-4x10-5,time 4 h.Intrinsic viscosity was found to increase with increasing Ti/(Bt+He)and decreasing Al/Ti and polymerization temperature.When the molar content of He,Al/Ti and polymerization temperature increased,the insoluble content in CH2Cl2 of copolymers decreased.When Ti/(Bt+He)and reaction time increased,the insoluble con-tent in CH2Cl2 of copolymers also increased.The crystal-lization and stereoregularity of poly(1-butene)decreased with the addition of He.展开更多
The cyclocopolymerization of 1,6-heptadiene （HPD） with ethylene （E） by a series of half-sandwich scandium alkyl catalysts bearing various auxiliary ligands have been examined. Significant ligand influence on the c...The cyclocopolymerization of 1,6-heptadiene （HPD） with ethylene （E） by a series of half-sandwich scandium alkyl catalysts bearing various auxiliary ligands have been examined. Significant ligand influence on the copolymerization activity and selectivity was observed. In combination with one equivalent of [Ph3C][B（C6F5）4], the half-sandwich scandium dialkyl complexes bearing a Lewis base THF （1） or an NHC side arm （2） yielded the copolymer products together with cross-linked polymers in the copolymerization of HPD with ethylene. In contrast, the THF-free complexes Cp＇Sc（CH2C6H4NMe2-o）2 （3： Cp＇ = C5H5; 4： Cp＇ = CsMe4SiMe3） and the phosphine oxide side-arm containing complex （C5Me4SiMe2CH2（O）PPh2）Sc（CH2SiM%）2 （5） showed excellent activity and selectivity for the cyclocopolymerization reaction, without giving cross-linked products. The 1H and 13C NMR analyses revealed that the resulting copolymers consist of E-E sequences and six-membered ring methylene-1,3-cyclohexane （MCH） and five-membered ring ethylene-1,2-cyclopentane （ECP） units. The HPD content in the co- polymer products could be easily controlled by changing the feeding amount of HPD under 1 atm of ethylene.展开更多
基金Project (Nos. 29734144 and 20274037) supported by the National Natural Science Foundation of China
文摘Ethylene/1-hexene was copolymerized by an unbridged zirconocene, (2-PhInd)2ZrCl2/MAO (methyl aluminoxane) at 0 °C and 50 °C respectively. High copolymerization activity and 1-hexene incorporation were observed at 0 °C, with the co- polymer formed having random sequence distribution and narrow molecular weight distribution. Ethylene polymerization at 50 °C showed high activity, but copolymerization at 50 °C showed much lower activity, which decreased sharply with increasing 1-hexene concentration in the monomer feed. Copolymer formed at 50 °C showed blocky sequence distribution and broad mo- lecular weight distribution. A mechanism model based on ligand rotation hindered by the propagation chain has been proposed to qualitatively explain the observed phenomena.
文摘Copolymerization of ethylene/1-octene was carried out in toluene withvarious concentrations of comonomer in the feed using Et(Ind)_2ZrCl_2/MAO (methyl alu-minoxane) as catalyst. It was found that with the increase of 1-octene concentration in thefeed the content of 1-octene in the copolymer increases, while the density, melting point,crystallinity and intrinsic viscosity of copolymer decrease. A copolymer with very lowdensity, containing 11.5 mol% of 1-octene (VLLDPE) can be produced with this catalystsystem. The effect of temperature and zirconium aluminum mole ratio of the catalyst onthe copolymerization was also investigated. The results of ^(13)C NMR determination of thecopolymer showed that the 1-octene units in the copolymer are principally isolated.
基金Project supported by the Major State Basic Research Development Program（No.G1999064801） the National Natural Science Foundation of China （No. 20372022） and the Research Fund for the Doctoral Program of Higher Education （No. 20020251002）.
文摘Complexes （R^1Cp）（R^2Ind）ZrCl2, the catalysts previously reported active for ethylene polymerization showed high activity in ethylene/1-hexene copolymerization and propylene polymerization in the presence of MAO. The content of 1-hexene in copolymers ranged from 1.2% to 3.2%. In propylene polymerization the complex 1 showed the highest activity, up to 1.2×10^6 g of polypropylene per mol of catalyst per hour. Based on the analysis of NMR spectral data, the relationships between complex structures and polymerization results were explored.
基金supported by the National High-Tech Research and Development Program of China(863 Program)(Grant No.2006AA03Z546).
文摘With TiCl4/MgCl2(Ti)and Al(i-Bu)3(Al)as catalysts,the thermoplastic copolymer of 1-butene(Bt)and 1-hexene(He)was synthesized successfully.The effects of Bt/He,Ti/(He+Bt),Al/Ti,temperature and reaction time on conversion,catalyst efficiency(CE),intrinsic viscosity([g])and insoluble content were studied.The copolymer was analyzed with Fourier transform-infrared(FTIR)and nuclear magnetic resonance(1H-NMR).Results showed that the optimal polymerization conditions were:He/Bt=0.25,temperature 40℃–50℃,Al/Ti=400–500,Ti/(Bt+He)=3x10-5-4x10-5,time 4 h.Intrinsic viscosity was found to increase with increasing Ti/(Bt+He)and decreasing Al/Ti and polymerization temperature.When the molar content of He,Al/Ti and polymerization temperature increased,the insoluble content in CH2Cl2 of copolymers decreased.When Ti/(Bt+He)and reaction time increased,the insoluble con-tent in CH2Cl2 of copolymers also increased.The crystal-lization and stereoregularity of poly(1-butene)decreased with the addition of He.
基金supported by Grant-in-aid for Scientific Research (B) (24350030 to M.N.)a Grant-in-Aid for Scientific Research (S) ( 21225004 to Z.H.) from JSPS+1 种基金the National Natural Science Foundation of China (21204008)the Fundamental Research Funds for the Central Universities (DUT12RC(3)94)
文摘The cyclocopolymerization of 1,6-heptadiene （HPD） with ethylene （E） by a series of half-sandwich scandium alkyl catalysts bearing various auxiliary ligands have been examined. Significant ligand influence on the copolymerization activity and selectivity was observed. In combination with one equivalent of [Ph3C][B（C6F5）4], the half-sandwich scandium dialkyl complexes bearing a Lewis base THF （1） or an NHC side arm （2） yielded the copolymer products together with cross-linked polymers in the copolymerization of HPD with ethylene. In contrast, the THF-free complexes Cp＇Sc（CH2C6H4NMe2-o）2 （3： Cp＇ = C5H5; 4： Cp＇ = CsMe4SiMe3） and the phosphine oxide side-arm containing complex （C5Me4SiMe2CH2（O）PPh2）Sc（CH2SiM%）2 （5） showed excellent activity and selectivity for the cyclocopolymerization reaction, without giving cross-linked products. The 1H and 13C NMR analyses revealed that the resulting copolymers consist of E-E sequences and six-membered ring methylene-1,3-cyclohexane （MCH） and five-membered ring ethylene-1,2-cyclopentane （ECP） units. The HPD content in the co- polymer products could be easily controlled by changing the feeding amount of HPD under 1 atm of ethylene.
