The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, ...The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.展开更多
A nickel-diimine catalyst [N, N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1, 3-butadiene nickel dibromide, DMN] was supported on palygorskite clay for ethylene slurry polymerization. The effect of support...A nickel-diimine catalyst [N, N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1, 3-butadiene nickel dibromide, DMN] was supported on palygorskite clay for ethylene slurry polymerization. The effect of supporting methods on the catalyst impregnation was studied and compared. Pretreatment of the support with methylalumi-noxane (MAO) followed by DMN impregnation gave higher catalyst loading and catalytic activity than the direct impregnation of DMN. Catalyst activity as high as 5.42×105g PE·molNi-1·h-1 was achieved at ethylene pressure of 6.87×105 Pa and polymerization temperature of 20℃. In particular, the morphological change of the support during MAO treatment was characterized and analyzed. It was found that nano-fiber clusters formed during the support pretreatment, which increased the surface area of the support and favored the impregnation of the catalyst. The investigation of polymerization behavior of supported catalyst revealed that the polymerization rate could be kept at a relatively high level for a long time, different from the homogeneous catalyst. By analyzing the SEM photographs of the polymer produced by the supported catalyst, the morphological evolution of polymer particles was preliminarily studied.展开更多
A new α-diimine ligand 1a, bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2a, {bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene}d...A new α-diimine ligand 1a, bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2a, {bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene}dibromo- nickel were successfully synthesized, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscope（FTIR）, elemental analysis and X-ray photoelectron spectroscopy（XPS）. α-Diimine ligand 1b, bis[N,N′-（2,6- dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2b, {bis[N,N′-（2,6-dimethyl- phenyl）imino]-2,3-butanediylidene}dibromonickel were also synthesized and characterized for comparison. The pre-catalyst 2a with sterically bulky, electron-donating group tert-butyl, activated by diethylaluminum chloride （DEAC） and tested in the polymerization of ethylene, was very highly active[2.01×107 g PE/（mol Ni？h？0.1 MPa）] and led to a very highly branched polyethylene（ca. 35―103 branches/1000 C）. The state of the polyethylene obtained varied from plastic, elastomer polymers to the oil-like hyperbranched polymers.展开更多
Bis （4-（4-amino-3, 5-diethylbenzyl）-2, 6-diethylphenylimino） acenaphthene] di- chloronickel （NiLCl2） was prepared and supported on SiO2 modified by methyl trichlorsilane（S-1） and on SiO2-MgCl2/TiCl4 （S-2） re...Bis （4-（4-amino-3, 5-diethylbenzyl）-2, 6-diethylphenylimino） acenaphthene] di- chloronickel （NiLCl2） was prepared and supported on SiO2 modified by methyl trichlorsilane（S-1） and on SiO2-MgCl2/TiCl4 （S-2） respectively. Two supported catalysts S-1 and S-2 used as catalysts for ethylene polymerization were studied and the influences of various polymerization conditions, including the polymerization temperature, cocatalysts, Al/Ni molar ratio on the catalytic activity, branching degree and branch length of PE were also investigated. The experimental results show that the supported catalysts exhibit higher catalytic activity for ethylene polymerization, the highest catalytic activity of S-1 using AlEt2Cl as cocatalyst at 50 ℃, reaching 5.8×10^5gPE/molNi·h, and needed lower Al/Ni molar ratio compared to homogeneous analogue.展开更多
Two novel copper complexes with methyl or trifluoro-substituted mono-β-diiminato ligands and one acetoxyl anion were synthesized and characterized by IR spectroscopy and elemental analysis for the first time. The str...Two novel copper complexes with methyl or trifluoro-substituted mono-β-diiminato ligands and one acetoxyl anion were synthesized and characterized by IR spectroscopy and elemental analysis for the first time. The structure of complex 2 bearing trifluoro substituents was further confirmed by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.377（4）, b = 11.727（6）, c = 12.913（7） ？, α = 116.569（6）, β = 98.829（7）, γ = 96.520（6）°, V = 966.2（8） ？3, Z = 2, Mr = 479.86, Dc = 1.649 g/cm3, F（000） = 482, μ = 1.205 mm-1, the final R = 0.0370 and w R = 0.0903 for 3430 observed reflections with I 〉 2σ（I）. These mono-β-diiminato copper complexes can effectively catalyze methacrylate（MA） polymerization when activated by MMAO. The introduction of fluoro groups into the N-aryl ring of β-diiminato ligands can greatly increase the catalytic activity of copper complexes as well as the molecular weight of PMA.展开更多
A Csp3-Csp3 coupling production of the original ligand molecule [（CMeN（2,6-iPr2C6H3））2]2 （1） and an antimony ionic compound with α-diimine ligand [LH3]＋[SbCl4]-（2, L = [（2,6-iPrC6H3）NC（Me）]2） were synthe...A Csp3-Csp3 coupling production of the original ligand molecule [（CMeN（2,6-iPr2C6H3））2]2 （1） and an antimony ionic compound with α-diimine ligand [LH3]＋[SbCl4]-（2, L = [（2,6-iPrC6H3）NC（Me）]2） were synthesized and characterized by 1H NMR, elemental analysis and single-crystal X-ray structural analysis. The crystal of compound 1 belongs to the orthorhombic system, space group Pbca with a = 21.173（4）, b = 10.1639（17）, c = 22.954（4） , V = 4939.8（14） 3, C56H78N4, Mr = 807.22, Z = 4, Dc = 1.085 g/cm3, μ（MoKα） = 0.062 mm-1, F（000） = 1768, S = 0.998, the final R = 0.0593 and wR = 0.1616 for 6481 observed reflections （Ⅰ 〉 2σ（Ⅰ）） and R = 0.0819 and wR = 0.1805 for all 28753 data. The crystal of compound 2 belongs to the triclinic system, space group P with a = 10.930（2）, b = 12.553（2）, c = 12.561（3） , α = 89.780（7）, β = 82.861（6）, γ = 68.598（4）o, V = 1590.5（5） 3, C28H43Cl4N2Sb, Mr = 671.19, Z = 2, Dc = 1.401 g/cm3, μ（MoKα） = 1.222mm-1, F（000） = 688, S = 0.989, the final R = 0.0294 and wR = 0.0616 for 7578 observed reflections （Ⅰ 〉 2σ（Ⅰ）） and R = 0.0366 and wR = 0.0639 for all 16515 data. Complex 1 can be rationalized as a result of Csp3-Csp3 coupling of two ligand molecules. The reaction of corres- ponding potassium salts with Sb（Ⅲ） chloride resulted in the antimony complex 2, in which the cationic moiety [LH3]^＋ is balanced by the presence of [SbCl4]- anion.展开更多
Diimine)nickel {[C 6 H 5 -N = C(CH 3 ) - C(CH 3 ) = N - QH 5 ]NiBr 2 }-TiCl 4 , abbreviated as NiL-TiCl 4 combined catalyst which is supported on MgCl 2 -SiO 2 carrier has been prepared, by using alkyl aluminum (AlR 3...Diimine)nickel {[C 6 H 5 -N = C(CH 3 ) - C(CH 3 ) = N - QH 5 ]NiBr 2 }-TiCl 4 , abbreviated as NiL-TiCl 4 combined catalyst which is supported on MgCl 2 -SiO 2 carrier has been prepared, by using alkyl aluminum (AlR 3 ) as the cocatalyst in place of methylaluminoxane (MAO) to catalyze ethylene oligomerization and copolymerization in situ. The influences of procedure for supporting NiL-TiCl 4 , the molar ratio of NiL to TiCl 4 , cocatalyst type and polymerization temperature on the catalytic performance were studied. The degree of branching and the composition of the branched chain of polymers produced have been investigated by IR and 13C-NMR spectra. The results show that the combined catalyst can synthesize the branched polyethylene with various banched chains .The polymerization reaction was monitored by gas chromatography and mass spectrometry (GC-MS). The results show that this catalyst promotes the oligomerization and copolymerization in situ for ethylene.展开更多
In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as het...In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as heterogeneous catalysts due to their excellent processability. In this study, nine types of heterogeneous procatalyst Ln/Ni2+-micas were synthesized via a one-pot preparation method, which includes both the condensation reaction of the ligand derivatives and the intercalation of the ligands into the Ni2+ ion-exchanged fluorotetrasilicic mica interlayer. The ligand structures of the prepared procatalysts were [Ln: R-N = C(Nap)-C(Nap) = N-R] [(Nap = 1,8-naphthdiyl) (L1, R = 2-MePh;L2, R = 2-FPh;L3, R = 2-BrPh;L4, R = 4-MePh;L5, R = 4-FPh;L6, R = 4-BrPh;L7, R = 2,4-F2Ph;L8, R = 2,4-Br2Ph;L9, R = 2,6-F2Ph). At 50℃ and 0.7 MPaethylene pressure, the triisobutylaluminum-activated L1-L6/Ni2+-mica showed a catalytic activity for the ethylene oligo-/polymerization in the range of 334 - 549 g-ethylene•g-cat–1•h–1. A high catalyst activity was obtained when the substituent having a larger steric bulk than that of a methyl substituent was introduced at the ortho-position of the aryl rings. The introduction of the fluorine substituent as a strong electron-withdrawing group to the para-position also increased the catalytic activity. The L2, L4, L5, and L6/Ni2+-micas showed moderate selectivities to oligomers consisting of C4-C20 in the range of 19.9 - 41.6 wt% at 50℃. The calculated Schulz-Flory constants α based on the mole fraction of C12 and C14 were within 0.61 - 0.78.展开更多
文摘The catalysis of olefin polymerization through the chain-walking process is a subject of great interest. In this contribution, the successful synthesis of a Brookhart-type unsymmetrical α-diimine nickel catalyst Ni, which contains both dibenzhydryl and phenyl groups, was determined by X-ray crystallography. The compound has a pseudo-tetrahedral geometry at the Ni center, showing pseudo-C2-symmetry. Upon activation with modified methylaluminoxane (MMAO), Ni1 exhibits high catalytic activity up to 1.02 × 107 g PE (mol Ni h)−1 toward ethylene polymerization, enabling the synthesis of high molecular weight branched polyethylene. The molecular weights and branching densities could be tuned over a very wide range. The polymerization results indicated the possibility of precise microstructure control, depending on the polymerization temperature. The branching densities were decreased with increasing the polymerization temperature.
基金Supported by the National Natural Science Foundation of China (No. 20376069).
文摘A nickel-diimine catalyst [N, N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1, 3-butadiene nickel dibromide, DMN] was supported on palygorskite clay for ethylene slurry polymerization. The effect of supporting methods on the catalyst impregnation was studied and compared. Pretreatment of the support with methylalumi-noxane (MAO) followed by DMN impregnation gave higher catalyst loading and catalytic activity than the direct impregnation of DMN. Catalyst activity as high as 5.42×105g PE·molNi-1·h-1 was achieved at ethylene pressure of 6.87×105 Pa and polymerization temperature of 20℃. In particular, the morphological change of the support during MAO treatment was characterized and analyzed. It was found that nano-fiber clusters formed during the support pretreatment, which increased the surface area of the support and favored the impregnation of the catalyst. The investigation of polymerization behavior of supported catalyst revealed that the polymerization rate could be kept at a relatively high level for a long time, different from the homogeneous catalyst. By analyzing the SEM photographs of the polymer produced by the supported catalyst, the morphological evolution of polymer particles was preliminarily studied.
基金Supported by the National Natural Science Foundation of China(No.20964003)
文摘A new α-diimine ligand 1a, bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2a, {bis[N,N′-（4-tert-butyl-2,6-dimethylphenyl）imino]-2,3-butanediylidene}dibromo- nickel were successfully synthesized, and characterized by 1H NMR, 13C NMR, Fourier transform infrared spectroscope（FTIR）, elemental analysis and X-ray photoelectron spectroscopy（XPS）. α-Diimine ligand 1b, bis[N,N′-（2,6- dimethylphenyl）imino]-2,3-butanediylidene and its corresponding Ni（II） complex 2b, {bis[N,N′-（2,6-dimethyl- phenyl）imino]-2,3-butanediylidene}dibromonickel were also synthesized and characterized for comparison. The pre-catalyst 2a with sterically bulky, electron-donating group tert-butyl, activated by diethylaluminum chloride （DEAC） and tested in the polymerization of ethylene, was very highly active[2.01×107 g PE/（mol Ni？h？0.1 MPa）] and led to a very highly branched polyethylene（ca. 35―103 branches/1000 C）. The state of the polyethylene obtained varied from plastic, elastomer polymers to the oil-like hyperbranched polymers.
基金Funded by the Science Foundation of Guangdong Province (No.031598)
文摘Bis （4-（4-amino-3, 5-diethylbenzyl）-2, 6-diethylphenylimino） acenaphthene] di- chloronickel （NiLCl2） was prepared and supported on SiO2 modified by methyl trichlorsilane（S-1） and on SiO2-MgCl2/TiCl4 （S-2） respectively. Two supported catalysts S-1 and S-2 used as catalysts for ethylene polymerization were studied and the influences of various polymerization conditions, including the polymerization temperature, cocatalysts, Al/Ni molar ratio on the catalytic activity, branching degree and branch length of PE were also investigated. The experimental results show that the supported catalysts exhibit higher catalytic activity for ethylene polymerization, the highest catalytic activity of S-1 using AlEt2Cl as cocatalyst at 50 ℃, reaching 5.8×10^5gPE/molNi·h, and needed lower Al/Ni molar ratio compared to homogeneous analogue.
基金Supported by the National Natural Science Foundation of China(21172269)the Applied Fundamental Research Project of Wuhan City(2015011701011598)
文摘Two novel copper complexes with methyl or trifluoro-substituted mono-β-diiminato ligands and one acetoxyl anion were synthesized and characterized by IR spectroscopy and elemental analysis for the first time. The structure of complex 2 bearing trifluoro substituents was further confirmed by single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P1 with a = 7.377（4）, b = 11.727（6）, c = 12.913（7） ？, α = 116.569（6）, β = 98.829（7）, γ = 96.520（6）°, V = 966.2（8） ？3, Z = 2, Mr = 479.86, Dc = 1.649 g/cm3, F（000） = 482, μ = 1.205 mm-1, the final R = 0.0370 and w R = 0.0903 for 3430 observed reflections with I 〉 2σ（I）. These mono-β-diiminato copper complexes can effectively catalyze methacrylate（MA） polymerization when activated by MMAO. The introduction of fluoro groups into the N-aryl ring of β-diiminato ligands can greatly increase the catalytic activity of copper complexes as well as the molecular weight of PMA.
基金supported by the National Natural Science Foundation of China (No. 21001016 and 20902112)
文摘A Csp3-Csp3 coupling production of the original ligand molecule [（CMeN（2,6-iPr2C6H3））2]2 （1） and an antimony ionic compound with α-diimine ligand [LH3]＋[SbCl4]-（2, L = [（2,6-iPrC6H3）NC（Me）]2） were synthesized and characterized by 1H NMR, elemental analysis and single-crystal X-ray structural analysis. The crystal of compound 1 belongs to the orthorhombic system, space group Pbca with a = 21.173（4）, b = 10.1639（17）, c = 22.954（4） , V = 4939.8（14） 3, C56H78N4, Mr = 807.22, Z = 4, Dc = 1.085 g/cm3, μ（MoKα） = 0.062 mm-1, F（000） = 1768, S = 0.998, the final R = 0.0593 and wR = 0.1616 for 6481 observed reflections （Ⅰ 〉 2σ（Ⅰ）） and R = 0.0819 and wR = 0.1805 for all 28753 data. The crystal of compound 2 belongs to the triclinic system, space group P with a = 10.930（2）, b = 12.553（2）, c = 12.561（3） , α = 89.780（7）, β = 82.861（6）, γ = 68.598（4）o, V = 1590.5（5） 3, C28H43Cl4N2Sb, Mr = 671.19, Z = 2, Dc = 1.401 g/cm3, μ（MoKα） = 1.222mm-1, F（000） = 688, S = 0.989, the final R = 0.0294 and wR = 0.0616 for 7578 observed reflections （Ⅰ 〉 2σ（Ⅰ）） and R = 0.0366 and wR = 0.0639 for all 16515 data. Complex 1 can be rationalized as a result of Csp3-Csp3 coupling of two ligand molecules. The reaction of corres- ponding potassium salts with Sb（Ⅲ） chloride resulted in the antimony complex 2, in which the cationic moiety [LH3]^＋ is balanced by the presence of [SbCl4]- anion.
基金This project was supported by the National Natural Science Foundation of China (No. 29874039) and the Foundation ofGuangdong Province (No. 031598).
文摘Diimine)nickel {[C 6 H 5 -N = C(CH 3 ) - C(CH 3 ) = N - QH 5 ]NiBr 2 }-TiCl 4 , abbreviated as NiL-TiCl 4 combined catalyst which is supported on MgCl 2 -SiO 2 carrier has been prepared, by using alkyl aluminum (AlR 3 ) as the cocatalyst in place of methylaluminoxane (MAO) to catalyze ethylene oligomerization and copolymerization in situ. The influences of procedure for supporting NiL-TiCl 4 , the molar ratio of NiL to TiCl 4 , cocatalyst type and polymerization temperature on the catalytic performance were studied. The degree of branching and the composition of the branched chain of polymers produced have been investigated by IR and 13C-NMR spectra. The results show that the combined catalyst can synthesize the branched polyethylene with various banched chains .The polymerization reaction was monitored by gas chromatography and mass spectrometry (GC-MS). The results show that this catalyst promotes the oligomerization and copolymerization in situ for ethylene.
文摘In the practical use for the production of the α-olefins, it is highly desired to develop a novel heterogeneous catalyst system. The metal complexes immobilized into the clay interlayers show a great potential as heterogeneous catalysts due to their excellent processability. In this study, nine types of heterogeneous procatalyst Ln/Ni2+-micas were synthesized via a one-pot preparation method, which includes both the condensation reaction of the ligand derivatives and the intercalation of the ligands into the Ni2+ ion-exchanged fluorotetrasilicic mica interlayer. The ligand structures of the prepared procatalysts were [Ln: R-N = C(Nap)-C(Nap) = N-R] [(Nap = 1,8-naphthdiyl) (L1, R = 2-MePh;L2, R = 2-FPh;L3, R = 2-BrPh;L4, R = 4-MePh;L5, R = 4-FPh;L6, R = 4-BrPh;L7, R = 2,4-F2Ph;L8, R = 2,4-Br2Ph;L9, R = 2,6-F2Ph). At 50℃ and 0.7 MPaethylene pressure, the triisobutylaluminum-activated L1-L6/Ni2+-mica showed a catalytic activity for the ethylene oligo-/polymerization in the range of 334 - 549 g-ethylene•g-cat–1•h–1. A high catalyst activity was obtained when the substituent having a larger steric bulk than that of a methyl substituent was introduced at the ortho-position of the aryl rings. The introduction of the fluorine substituent as a strong electron-withdrawing group to the para-position also increased the catalytic activity. The L2, L4, L5, and L6/Ni2+-micas showed moderate selectivities to oligomers consisting of C4-C20 in the range of 19.9 - 41.6 wt% at 50℃. The calculated Schulz-Flory constants α based on the mole fraction of C12 and C14 were within 0.61 - 0.78.
基金supported by the National Key Technology R&D Program of China (2007BAE14B01‐06)the Fund for Creative Research Groups of the National Natural Science Foundation of China (50621302)~~
