A new polymer-supported metallocene catalyst has been prepared, The polymer-supported metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62x10(7) gPE/molZr.h, the molecula...A new polymer-supported metallocene catalyst has been prepared, The polymer-supported metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62x10(7) gPE/molZr.h, the molecular weight of the polyethylene produced was Mn = 1.29x10(5). about 3-4 times those of corresponding homogeneous zirconocenes. The polymer-supported metallocene keeps the characteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable to gas phase and slurry processes: easy to prepare in low cost: relatively high activity and lower MAO/Zr ratio; lower inorganic residues in the polyolefins as compared to cases of SiO2, Al2O3 or MgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of the resulting polymer.展开更多
Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preact...Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preactivated with methylaluminoxane （MAO） on calcinated silica at different temperatures. Polymerizations of ethylene were conducted at different temperatures to find the optimized polymerization temperature for maximum activity of the catalyst. The Me2Si bridge catalyst showed higher activity at the lower polymerization temperature compared to the Et bridge catalyst. The highest catalytic activities were obtained at temperatures about 50 ~C and 70 ~C for Me2Si（Ind）2ZrC1JMAO and Et（Ind）zZrCI2/MAO catalysts systems, respectively. Inductively coupled plasma-atomic emission spectroscopy results and polymerization activity results confirmed that the best temperature for calcinating silica was about 450 ℃ for both catalysts systems. The melting points of the produced polyethylene were about 130 ℃, which could be attributed to the linear structure of HDPE.展开更多
Spherical MgCl 2 supported metallocene catalyst was prepared by supporting MAO on carrier which was prepared from MgCl 2 ·n EtOH.Ethylene polymerization was carried out by addition of MAO/MgCl 2,different metallo...Spherical MgCl 2 supported metallocene catalyst was prepared by supporting MAO on carrier which was prepared from MgCl 2 ·n EtOH.Ethylene polymerization was carried out by addition of MAO/MgCl 2,different metallocenes and alkylaluminum,in the absence of soluble MAO.It shows high activity for ethylene polymerization at lower Al/Zr(Al/Zr=45).The effect of concentration of Al( i Bu) 3 on polymerization activities and activation of Et(Ind) 2ZrCl 2 were studied.Kinetic behavior of ethylene polymerization on spherical MgCl 2 supported metallocene catalyst was investigated,which indicated the polymers obtained by reaction could affect the diffusion of ethylene in hexane under the experiment condidtion.Different aluminium alkyls have great impact on the whole polymerization behavior,and the relative reactivity decreases in the following order:Al( i Bu) 3>AlEt 3>AlMe 3>AlEt 2Cl,in which Al( i Bu) 3 shows the highest catalytic activity (5 78×10 7 g PE/mol\|Zr·h).展开更多
A novel polymer-supported metallocene catalyst has been prepared. The polymer-support-ed metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62× 107 g/(mol · h), ...A novel polymer-supported metallocene catalyst has been prepared. The polymer-support-ed metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62× 107 g/(mol · h), the molecular weight of the polyethylene produced was Mn = 1.29 × 105 , about 3～4 times those prepared by corresponding homogeneous zirconocenes. The polymer-supported metallocene poly(styrene-acrylamide)supported zirconocene]keeps thecharacteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable togas phase and slurry processes; easy to prepare in low cost; relatively high activity and lowerMAO/Zr ratio ; lower inorganic residues in the polyolefins as compared to those using SiO2, Al2O3 orMgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of theresulting polymer.展开更多
文摘A new polymer-supported metallocene catalyst has been prepared, The polymer-supported metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62x10(7) gPE/molZr.h, the molecular weight of the polyethylene produced was Mn = 1.29x10(5). about 3-4 times those of corresponding homogeneous zirconocenes. The polymer-supported metallocene keeps the characteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable to gas phase and slurry processes: easy to prepare in low cost: relatively high activity and lower MAO/Zr ratio; lower inorganic residues in the polyolefins as compared to cases of SiO2, Al2O3 or MgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of the resulting polymer.
基金financially supported by the National Iranian Petrochemical Company Research and Technology(NIPC-RT)
文摘Ethylene polymerization was carried out by immobilization of rac-ethylenebis（1-indenyl）zirconium dichloride （Et（Ind）2ZrCl2） and rac-dimethylsilylbis（1-indenyl）zirconium dichloride （Me2Si（Ind）2ZrCl2） preactivated with methylaluminoxane （MAO） on calcinated silica at different temperatures. Polymerizations of ethylene were conducted at different temperatures to find the optimized polymerization temperature for maximum activity of the catalyst. The Me2Si bridge catalyst showed higher activity at the lower polymerization temperature compared to the Et bridge catalyst. The highest catalytic activities were obtained at temperatures about 50 ~C and 70 ~C for Me2Si（Ind）2ZrC1JMAO and Et（Ind）zZrCI2/MAO catalysts systems, respectively. Inductively coupled plasma-atomic emission spectroscopy results and polymerization activity results confirmed that the best temperature for calcinating silica was about 450 ℃ for both catalysts systems. The melting points of the produced polyethylene were about 130 ℃, which could be attributed to the linear structure of HDPE.
文摘Spherical MgCl 2 supported metallocene catalyst was prepared by supporting MAO on carrier which was prepared from MgCl 2 ·n EtOH.Ethylene polymerization was carried out by addition of MAO/MgCl 2,different metallocenes and alkylaluminum,in the absence of soluble MAO.It shows high activity for ethylene polymerization at lower Al/Zr(Al/Zr=45).The effect of concentration of Al( i Bu) 3 on polymerization activities and activation of Et(Ind) 2ZrCl 2 were studied.Kinetic behavior of ethylene polymerization on spherical MgCl 2 supported metallocene catalyst was investigated,which indicated the polymers obtained by reaction could affect the diffusion of ethylene in hexane under the experiment condidtion.Different aluminium alkyls have great impact on the whole polymerization behavior,and the relative reactivity decreases in the following order:Al( i Bu) 3>AlEt 3>AlMe 3>AlEt 2Cl,in which Al( i Bu) 3 shows the highest catalytic activity (5 78×10 7 g PE/mol\|Zr·h).
文摘A novel polymer-supported metallocene catalyst has been prepared. The polymer-support-ed metallocene displayed considerably high activity in ethylene polymerization, the highest being 3.62× 107 g/(mol · h), the molecular weight of the polyethylene produced was Mn = 1.29 × 105 , about 3～4 times those prepared by corresponding homogeneous zirconocenes. The polymer-supported metallocene poly(styrene-acrylamide)supported zirconocene]keeps thecharacteristics of homogeneous metallocene catalysts, and offers some features, such as adaptable togas phase and slurry processes; easy to prepare in low cost; relatively high activity and lowerMAO/Zr ratio ; lower inorganic residues in the polyolefins as compared to those using SiO2, Al2O3 orMgCl2; unitary active structure, no complex surface as with SiO2; good control of morphology of theresulting polymer.
