POLYMERIZATION OF METHYL METHACRYLATE WITH ETHYLENE BRIDGED HETERODINUCLEAR METALLOCENE OF SAMARIUM AND TITANIUM-STUDY ON SYNERGISM AND KINETICS

ＩＮＴＲＯＤＵＣＴＩＯＮＨｅｔｅｒｏｄｉｎｕｃｌｅａｒｃｏｍｐｌｅｘｅｓａｒｅｏｆｇｒｅａｔｉｍ ｐｏｒｔａｎｃｅｆｏｒｔｈｅｓｔｕｄｙｏｆｔｈｅｓｙｎｅｒｇｉｓｔｉｃｅｆｆｅｃｔｓｆｏｕｎｄｉｎｂｉｍｅｔａｌｌｉｃｃａｔａｌｙｓｉｓ (Ａｄａｍｓ,1 988;Ｒｅｄｄｙｅｔａｌ.,1 989;Ｚｈｅｎｇｅｔａｌ.,1 989;Ｗｅｒｎｅｒｅｔａｌ.,1 992 ) ,ｗｈｉｃｈｉｎｄｉｃａｔｅｄｄｉｓｔｉｎｃ ｔｉｖｅｅｌｅｃｔｒｏｎｉｃ ,ｅｌｅｃｔｒｏｃｈｅｍｉｃａｌａｎｄｍａｇｎｅｔｉｃｐｒｏｐｅｒｔｉｅｓａｒｉｓｉｎｇｆｒｏ…     

茂金属配合物[(eta5-C5H4 Si2 Me5)Mo-Br(CO)3]的电子结构研究

运用G98W，采用Lan12dz基组，对茂金属配合物[eta^5-C5H4Si2Me5)Mo-Br(CO)3]进行从头算研究，探讨配合物结构单元的稳定性，分子轨道能量，原子净电荷布局规律，以及一些前沿分子轨道的组成特征等，结果表明，标题配合物结构在能量上是稳定的，作为结构单元而存在，为茂金属配合物的合成，分子组装分析提供参考。     

Polymerization of methyl methacrylate with ethylene bridged heterodinuclear metallocene of samarium and titanium-study on synergism and kinetics

Comparison of MMA polymerization results with samarocene chloride, titanocene chloride and the title heterodinuclear (Sm−Ti) catalyst, respectively, showed synergism in the Sm-Ligand-Ti system, which obviously influenced the polymerization behaviors, for example, of yeilding higher activity and higher molecular weight polymer. Kinetic studies on polymerization of MMA with ethylene bridged samarocene and titanocene chloride/Al(i-Bu)₃ showed that the polymerization rate was first-order on the catalyst concentration, and 1.9-order on the monomer. The overall activation energy measured was 52.8 kJ/mol. Project supported by NSFC (No. 20074028), and SINOPEC(X598037).     

THE POLYMERIZATION OF METHYL METHACRYLATE WITH A NEW TIN-BRIDGED YTTROCENE/Al(i-Bu)_3

ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｔｈｅｐｏｌｙｍｅｒｉｚａｔｉｏｎｏｆｍｅｔｈｙｌｍｅｔｈａｃｒｙｌａｔｅ(ＭＭＡ)ｗｉｔｈｒａｒｅｅａｒｔｈｃａｔａｌｙｓｔｓｗａｓｒｅａｌｉｚｅｄｆｏｒｔｈｅｆｉｒｓｔｔｉｍｅｉｎ1991,ａｓｅｒｉｅｓｏｆｎｅｗｒａｒｅｅａｒｔｈｃａｔａｌｙｓｔｓｙｓｔｅｍｓｓｕｃｈａｓＮｄ(Ｐ204)3/Ａｌ(ｉＢｕ)3,Ｎｄ(Ｐ204)3/Ａｌ(ｉＢｕ)3/ＣＣｌ4,Ｎｄ(Ｏｃｔ)3/Ａｌ(ｉＢｕ)3,Ｌｎ(ａｃａｃ)3/ＢｕＭｇＣｌ,Ｙ(ａｃａｃ)3/Ａｌ(ｉＢｕ)3/ＢｕＬｉ,Ｎｄ(ｎａｐｈ)3/ＢｕＬｉ,ａｎｄＮｄ(Ｏ…     

Polymerization of methyl methacrylate with iron-ytterbium dinuclear metallocene catalyst

A novel iron-ytterbium dinuclear catalyst, FcB(MeCp) Yb (MeCp) Cl (Fc: ferrocenyl, B: diethylene ether), was synthesized for the polymerization of methyl methacrylate (MMA). Synergistic effects between the ferrocenyl group and the lanthanocene part were investigated regarding their catalytic behaviors. UV, IR, GPC and NMR were used to characterize the structures of the catalyst and polymer. Kinetic study showed that polymerization is first order in monomer concentration and fractional order (0.78) in the catalyst. The bimetallic complex is a good catalyst for the polymerization of MMA, giving high molecular weight PMMA with 78% syndiotactivity. Project (29774021) supported by NSFC and Laboratory of Rare-Earth Chemistry and Physics, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences     

NEW MATERIALS BY POLYMERIZATION OF OLEFINS AND STYRENE BY METALLOCENE/MAO CATALYSTS

ＩＮＴＲＯＤＵＣＴＩＯＮＭｅｔａｌｌｏｃｅｎｅｓｉｎｃｏｍｂｉｎａｔｉｏｎｗｉｔｈｍｅｔｈｙｌａｌｕ ｍｏｘａｎｅｏｒｐｅｒｆｌｕｏｒｉｎａｔｅｄｂｏｒａｔｅｓａｓｃｏｃａｔａｌｙｓｔｆｏｒｍｅｘｔｒｅｍｅｌｙａｃｔｉｖｅｃａｔａｌｙｓｔｓｆｏｒｔｈｅｐｏｌｙｍｅｒ ｉｚａｔｉｏｎｏｆｏｌｅｆｉｎｓ ,ｃｙｃｌｏｏｌｅｆｉｎｓ,ｓｔｙｒｅｎｅ ,ａｎｄｂｕｔａｄｉｅｎｅａｒｅｎｏｗｕｓｅｄｉｎｉｎｄｕｓｔｒｉａｌｐｒｏｃｅｓｓｅｓ(Ｓｃｈｅｉｒｓｅｔａｌ.,2 0 0 0 ;Ｋａｍｉｎｓｋｙｅｔａｌ.,1 997ｂ ;Ｂｏ…     

Strong influences of polymerization temperature on ethylene/1-hexene copolymerization catalyzed by (2-PhInd)2ZrCl2/methyl aluminoxane

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 copolymer 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 molecular weight distribution. A mechanism model based on ligand rotation hindered by the propagation chain has been proposed to qualitatively explain the observed phenomena. Project (Nos. 29734144 and 20274037) supported by the National Natural Science Foundation of China     

POLYMERIZATION OF METHYL METHACRYLATE WITH IRON-YTTERBIUM DINUCLEAR METALLOCENE CATALYST

ＩＮＴＲＯＤＵＣＴＩＯＮＨｅｔｅｒｏｄｉｎｕｃｌｅａｒｃｏｍｐｌｅｘｅｓａｒｅｏｆｇｒｅａｔｉｎｔｅｒ ｅｓｔｆｏｒｔｈｅｓｔｕｄｙｏｆｓｙｎｅｒｇｉｓｔｉｃｅｆｆｅｃｔｓｆｏｕｎｄｉｎｂｉｍｅｔａｌｌｉｃｃａｔａｌｙｓｉｓ(Ｄｏｍｂｅｋ ,1 985;ＪｎＬｉｎｇｅｔａｌ.,1 993 ;Ｍｃｃｏｌｌｕｍｅｔａｌ.,1 996) .Ｍｏｒｅａｎｄｍｏｒｅｓｙｎｔｈｅｔｉｃｒｏｕｔｅｓｈａｖｅｂｅｅｎｒｅｐｏｒｔｅｄｉｎｔｈｅｌａｓｔｄｅｃａｄｅ(Ｈａｒｔｅｒｅｔａｌ.,1 989;Ｓｃｏｔｔｅｔａｌ.,1 993 ;Ｄｉａｍｏｎｄｅｔａｌ.…     

The polymerization of methyl methacrylate with a new Tin-bridged yttrocene/Al(I-Bu)3

A new catalyst composed of Tin-bridged yttrocene Ph₂Sn(MeCp)₂YCI (MeCp=methylcyclopentadienyl) and Al (i-Bu)₃ was successfully developed for the polymerization of methyl methacrylate (MMA). Detailed study of factors (such as the molar ratio of Al/Cat., catalyst concentration, various solvents, temperature and time) influencing polymerization reaction indicated that the catalytic active species may be still somewhat stable at high temperature and still have a long catalytic lifetime.¹H NMR spectrum showed about 65% syndiotactic content in the polymethyl methacrylate (PMMA) prepared. From kinetic studies, the polymerization rate equation may be expressed as Rp=Kp[Cat.]^2.4. The overall activation energy of polymerization is 20.9±3.1 kJ/mol. Project(29774021) supported by the Natural Science Foundation of China and National Laboratory of Element-Organic Chemistry, Nakai, University.     

Strong influences of polymerization temperature on ethylene/1-hexene copolymerization catalyzed by (2-PhInd)_2ZrCl_2/methyl aluminoxane

Ethylene/1-hexene was copolymerized by an unbridged zirconocene, (2-PhInd)2ZrCl2/MAO (methyl aluminoxane) at 0 ℃ and 50 ℃ respectively. High copolymerization activity and 1-hexene incorporation were observed at 0 ℃, with the copolymer formed having random sequence distribution and narrow molecular weight distribution. Ethylene polymerization at 50 ℃showed high activity, but copolymerization at 50 ℃ showed much lower activity, which decreased sharply with increasing 1-hexene concentration in the monomer feed. Copolymer formed at 50 ℃ showed blocky sequence distribution and broad molecular weight distribution. A mechanism model based on ligand rotation hindered by the propagation chain has been proposed to qualitatively explain the observed phenomena.