An unbridged zirconocene complex bis(1,2-diphenylcyclopentadienyl)zirconium dichloride [(1,2-Ph2-C5H3)2ZrCl2] 1 has been synthesized and structurally characterized. When activated by MAO, 1 produces ultra-high molecul...An unbridged zirconocene complex bis(1,2-diphenylcyclopentadienyl)zirconium dichloride [(1,2-Ph2-C5H3)2ZrCl2] 1 has been synthesized and structurally characterized. When activated by MAO, 1 produces ultra-high molecular weight polyethylene with high melting transition temperature, as well as atactic oligopropylene with average molecular weight of ~1150 g mol-1.展开更多
Three ansa-metallocenes(Me_2C)(Me_2Si)Cp_2TiCl_2(1),[(CH_2)_5C](Me_2Si)Cp_2TiCl_2 (2)and (Me_2C)(Me_2Si)Cp_2ZrCl_2 (3)with larger dihedral angles and longer distance from metal to the center of Cp planes were synthesi...Three ansa-metallocenes(Me_2C)(Me_2Si)Cp_2TiCl_2(1),[(CH_2)_5C](Me_2Si)Cp_2TiCl_2 (2)and (Me_2C)(Me_2Si)Cp_2ZrCl_2 (3)with larger dihedral angles and longer distance from metal to the center of Cp planes were synthesized and used as catalysts for ethylene polymerization in the presence of methylaluminoxane (MAO).In the case of ethylene polymerization,compared the feature structures of unbridged metallocenes, singly bridged metallocenes and doubly bridged metallocenes 1,2,3,there exhibit the relationship bet...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
Two new half-sandwich zirconium（IV） complexes bearing salicylaldimine ligands of the type Cp＊Zr[2-tBu-4-R-6-（CH=NiPr）C6H2O]C12[R=H（1）, tBu（2）] were prepared by the reaction of Cp＊ZrC13 with the corresponding...Two new half-sandwich zirconium（IV） complexes bearing salicylaldimine ligands of the type Cp＊Zr[2-tBu-4-R-6-（CH=NiPr）C6H2O]C12[R=H（1）, tBu（2）] were prepared by the reaction of Cp＊ZrC13 with the corresponding lithium of salicylaldimine ligands 2-tBu-4-R-6-（CH=NiPr）C6H2OLi[R=H（LiLa）, tBu（LiLb）]. Com- plexes 1 and 2 were characterized by 1H NMR, BC NMR spectroscopy and elemental analysis. When activated with AliBu3 and Ph3CB（C6F5）4, both complexes 1 and 2 exhibited reasonable catalytic activities for ethylene polymeriza- tion, producing polyethylenes with moderate molecular weight. Complexes 1 and 2 also exhibited reasonable catalyt- ic activities for ethylene copolymerization with 1-hexene, producing poly（ethylene-co-l-hexene）s with moderate molecular weight and reasonable 1-hexene content.展开更多
Synthesis and elemental analysis of metallocene analogic complexes (NpCpTiCl 2) containing the azole ligand (Np) are described,in which Np is Pr=Pyrolyl (C 4H 4N)(1); Id=Indolyl (C 8H 6N)(2); Ai=7 Azaindolyl (C 7H 5N ...Synthesis and elemental analysis of metallocene analogic complexes (NpCpTiCl 2) containing the azole ligand (Np) are described,in which Np is Pr=Pyrolyl (C 4H 4N)(1); Id=Indolyl (C 8H 6N)(2); Ai=7 Azaindolyl (C 7H 5N 2)(3); Iz=Indazolyl (C 7H 5N 2)(4); Bi=Benzimidazolyl (C 7H 5N 2)(5),respectively.It is proved by the experiments that NpCpTiCl 2 is active for ethylene polymerization at 30℃ and 0.1?mPa with MAO activation,and the results show that the activity of 1 and 2 which contain one nitrogen in the azole ring is higher than 4 and 5 which contain two nitrogens,while 3 is inactive.For the NpCpTiCl 2/MAO system,the activity is “up and down” type with increase in the Al/Ti molar ratio,and up to the highest when the Al/Ti molar ratio is about 500.The polyethylene obtained is characteristic of narrow distribution with molecular weight M w around 35×10 4 and molecular weight ratio M w/ M n less than 3.展开更多
Synthesis of half metallocene complexes ([O,N]CpTiCl 2) containing 8 hydroxy quinoline ligand is described.The results indicate that [O,N]CpTiCl 2 is active for ethylene polymerization at 30℃ and 0.1?mPa with MAO act...Synthesis of half metallocene complexes ([O,N]CpTiCl 2) containing 8 hydroxy quinoline ligand is described.The results indicate that [O,N]CpTiCl 2 is active for ethylene polymerization at 30℃ and 0.1?mPa with MAO activation,and exhibits much higher activity than CpTiCl\-3.The results show that when there is an electron donor substituent next to N,such as a methyl,the activity of [O,N]CpTiCl 2 increases greatly; however,if there is an electron acceptor substituent,such as nitro in the benzene ring,it is inactive.For the [O,N]CpTiCl 2/MAO system,the polymerization rate is “up and down” type with increasing the Al/Ti molar ratio.The activity reaches its maximum at molar ratio of Al/Ti = 500,which is over 1×10 5?gPE/molTi·h.The activity decreases as the polymerization time is longer.The polyethylene obtained is characteristic of narrow molecular distribution with molecular weight M w around 40×10 4 and molecular weight ratio M w/ M n=2 8.展开更多
文摘An unbridged zirconocene complex bis(1,2-diphenylcyclopentadienyl)zirconium dichloride [(1,2-Ph2-C5H3)2ZrCl2] 1 has been synthesized and structurally characterized. When activated by MAO, 1 produces ultra-high molecular weight polyethylene with high melting transition temperature, as well as atactic oligopropylene with average molecular weight of ~1150 g mol-1.
基金the National Natural Science Foundation of China(No.50573018)
文摘Three ansa-metallocenes(Me_2C)(Me_2Si)Cp_2TiCl_2(1),[(CH_2)_5C](Me_2Si)Cp_2TiCl_2 (2)and (Me_2C)(Me_2Si)Cp_2ZrCl_2 (3)with larger dihedral angles and longer distance from metal to the center of Cp planes were synthesized and used as catalysts for ethylene polymerization in the presence of methylaluminoxane (MAO).In the case of ethylene polymerization,compared the feature structures of unbridged metallocenes, singly bridged metallocenes and doubly bridged metallocenes 1,2,3,there exhibit the relationship bet...
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.
基金Supported by the National Natural Science Foundation of China（No.21204082）.
文摘Two new half-sandwich zirconium（IV） complexes bearing salicylaldimine ligands of the type Cp＊Zr[2-tBu-4-R-6-（CH=NiPr）C6H2O]C12[R=H（1）, tBu（2）] were prepared by the reaction of Cp＊ZrC13 with the corresponding lithium of salicylaldimine ligands 2-tBu-4-R-6-（CH=NiPr）C6H2OLi[R=H（LiLa）, tBu（LiLb）]. Com- plexes 1 and 2 were characterized by 1H NMR, BC NMR spectroscopy and elemental analysis. When activated with AliBu3 and Ph3CB（C6F5）4, both complexes 1 and 2 exhibited reasonable catalytic activities for ethylene polymeriza- tion, producing polyethylenes with moderate molecular weight. Complexes 1 and 2 also exhibited reasonable catalyt- ic activities for ethylene copolymerization with 1-hexene, producing poly（ethylene-co-l-hexene）s with moderate molecular weight and reasonable 1-hexene content.
文摘Synthesis and elemental analysis of metallocene analogic complexes (NpCpTiCl 2) containing the azole ligand (Np) are described,in which Np is Pr=Pyrolyl (C 4H 4N)(1); Id=Indolyl (C 8H 6N)(2); Ai=7 Azaindolyl (C 7H 5N 2)(3); Iz=Indazolyl (C 7H 5N 2)(4); Bi=Benzimidazolyl (C 7H 5N 2)(5),respectively.It is proved by the experiments that NpCpTiCl 2 is active for ethylene polymerization at 30℃ and 0.1?mPa with MAO activation,and the results show that the activity of 1 and 2 which contain one nitrogen in the azole ring is higher than 4 and 5 which contain two nitrogens,while 3 is inactive.For the NpCpTiCl 2/MAO system,the activity is “up and down” type with increase in the Al/Ti molar ratio,and up to the highest when the Al/Ti molar ratio is about 500.The polyethylene obtained is characteristic of narrow distribution with molecular weight M w around 35×10 4 and molecular weight ratio M w/ M n less than 3.
文摘Synthesis of half metallocene complexes ([O,N]CpTiCl 2) containing 8 hydroxy quinoline ligand is described.The results indicate that [O,N]CpTiCl 2 is active for ethylene polymerization at 30℃ and 0.1?mPa with MAO activation,and exhibits much higher activity than CpTiCl\-3.The results show that when there is an electron donor substituent next to N,such as a methyl,the activity of [O,N]CpTiCl 2 increases greatly; however,if there is an electron acceptor substituent,such as nitro in the benzene ring,it is inactive.For the [O,N]CpTiCl 2/MAO system,the polymerization rate is “up and down” type with increasing the Al/Ti molar ratio.The activity reaches its maximum at molar ratio of Al/Ti = 500,which is over 1×10 5?gPE/molTi·h.The activity decreases as the polymerization time is longer.The polyethylene obtained is characteristic of narrow molecular distribution with molecular weight M w around 40×10 4 and molecular weight ratio M w/ M n=2 8.
