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Phosphine/Benzocyclone-based Neutral Nickel Catalysts for ethylene polymerization and Copolymerization with Polar Monomers

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Chinese Journal of Polymer Science 2024年第2期42卷 202-212,I0007页

作者： Fei Wang Li Pan Vladislav A.Tuskaev Svetlana Ch.Gagieva Yue-Sheng Li Tianjin Key Lab of Composite&Functional Materials School of Material Science and EngineeringTianjin UniversityTianjin300072China Department of Chemistry Lomonosov Moscow State UniversityRussian Federation InstitutionLeninskie Gory 1Moscow119991Russian Federation A N Nesmeyanov Institute of Organoelement Compounds Russian Academy of SciencesVavilova st.28Moscow119991Russian Federation

The efficient copolymerization of olefin with polar monomers using nickel-based catalysts presents a longstanding challenge. In this contribution, three phosphine-benzocyclone ligands and corresponding neutral nickel catalysts(Ni1: Ar = Ph;Ni2: Ar = 2-(C_(6)H_(5))C_(6)H_(4);Ni3: Ar = 2-[2',6'-(Me O)_(2)-C_(6)H3]C_(6)H_(4)) were prepared and applied for the ethylene polymerization and copolymerization with polar monomers without any cocatalyst. The bulky substituent groups in complexes Ni2 and Ni3 contributed to high catalytic activities(up to 7.24×10^(6) and 9.04×10^(6)g·mol Ni^(-1)·h^(-1), respectively), and produced high-molecular-weight polyethylene(Mw up to 545.7 k Da). Complex Ni3 exhibited high activities for ethylene polymerization at the level of 10^(6) g·mol Ni^(-1)·h^(-1) across a wide range from 30 ℃ to 120 ℃, exhibiting excellent high temperature tolerance. These nickel complexes were also effectively employed in the copolymerization of ethylene with methyl acrylate, ethyl acrylate, butyl acrylate and lauryl acrylate, producing copolymers with high molecular weights(Mw up to 80.5 k Da) and high polar monomer incorporation(up to 8.2 mol%). Microstructure analyses revealed that the introduction of large sterically hindered substituents facilitated the incorporation of polar functional units into the polymer backbone. This study demonstrates the potential of these nickel-based catalysts for efficient copolymerization of olefin with polar monomers.

关键词： Neutral nickel catalyst ethylene polymerization Copolymerization Polar acrylate monomers

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Peculiarities of ethylene polymerization Reactions with Bis(imino)pyridyl Complexes of CoCl_(2) and FeCl_(2)

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Chinese Journal of Polymer Science 2024年第4期42卷 492-500页

作者： Laura A.Rishina Yury V.Kissin Svetlana S.Lalayan Artem A.Antonov Vadim G.Krasheninnikov Alexander A.Gulin N.N.Semenov Federal Research Center for Chemical Physics Russian Academy of Sciences4 Kosygin St.Moscow119991Russia Department of Chemistry and Chemical Biology RutgersThe State University of New Jersey123 Bevier Rd.PiscatawayNJ08854USA Boreskov Institute of Catalysis Russian Academy of Sciences5 Lavrentieva Prosp.Novosibirsk630090Russia

The article describes ethylene polymerization reactions with transition metal catalysts based on complexes of CoCl_(2) and FeCl_(2) with an N,N,N-tridentate ligand 2,6-bis[1-(2,6-dimethylphenylimino)ethyl]pyridine. The complexes are converted into polymerization catalysts by reacting them either with polymethylalumoxane (MAO) or with a combination of Al(C2H5)2Cl and Mg(C4H9)2 at an [Al]:[Mg] ratio of ~3. Both MAO-activated complexes readily polymerize ethylene at 35 ℃ with the formation of linear, low molecular weight polymers with a narrow molecular weight distribution. The same complexes, when activated with the Al(C2H5)2Cl-Mg(C4H9)2 combination, form multi-center catalysts and generate polyethylenes with a broad molecular weight distribution.

关键词： ethylene polymerization Bis(imino)pyridyl complexes of CoCl_(2)and FeCl_(2) Molecular-weight distribution Polymer chain structure

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High Temperature Iron ethylene polymerization Catalysts Bearing N,N,N'-2-(1-(2,4-Dibenzhydryl-6-fluorophenylimino)ethyl)-6-(1-(arylphenylimino)ethyl)pyridines

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Chinese Journal of Polymer Science 2024年第2期42卷 188-201,I0007页

作者： Chantsalnyam Bariashir Qiu-Yue Zhang Bayasgalan Ulambayar Gregory A.Solan Tong-Ling Liang Wen-Hua Sun Institute of Chemistry and Chemical Technology Mongolian Academy of SciencesUlaanbaatar13330Mongolia Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China Department of Chemistry University of LeicesterUniversity RoadLeicesterLE17RHUK State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

The N,N,N'-ferrous chloride complexes,[2-{CMeN(2,4-(CHPh)_(2)-6-FC_(6)H_(2))}-6-(CMeNAr)C_(5)H_(3)N]FeCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3) Fe1,2,6-Et_(2)C_(6)H_(3)Fe2,2,6-^(i)Pr_(2)C_(6)H_(3) Fe3,2,4,6-Me_(3)C_(6)H_(2) Fe4 and 2,6-Et_(2)-4-MeC_(6)H_(2) Fe5),each possessing one N-2,4-dibenzhydryl-6-fluorophenyl group,were readily synthesized from their respective unsymmetrical bis(imino)pyridines,L1-L5.Structural identification of Fe2 highlighted the variation in the steric properties provided by the dissimilar N-aryl groups.Following pre-treatment with either MAO or MMAO,complexes Fe1-Fe5 all displayed,at an operating temperature of 80℃,high activities for ethylene polymerization with levels falling in the order:Fe4> Fe1> Fe5> Fe2> Fe3.Notably,Fe4/MAO displayed the highest activity of 1.94×10^(7) g_(PE)·mol_(Fe)^(-1)·h^(-1) of the study with only a modest loss in performance at 90℃.Generally,the resulting polyethylenes were highly linear(T_(m) range:122-132℃),narrowly disperse and of low molecular weight(M_(w) range:6.73-46.04kg·mol^(-1)),with the most sterically hindered Fe3 forming the highest molecular weight polymer of the series.End-group analysis by ^(1)H-and ^(13)CNMR spectroscopy revealed saturated alkyl(n-propyl and i-propyl) and unsaturated vinyl chain ends indicative of the role of both β-H elimination and chain transfer to aluminum as termination pathways.By comparison with previou sly reported iron precatalysts with similar tridentate ligand skeletons,it is evident that the introduction of a large benzhydryl group in combination with a fluorine as the ortho-substituents of one N-aryl group has the effect of enhancing thermal stability of the iron polymerization catalyst whilst maintaining appreciable polymer molecular weight.

关键词： Iron catalyst ethylene polymerization Linear polyethylene Fluoride effect Thermal stability

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Synthesis of Branched Polyethylene via Bulky α-Diimine Nickel(II)-Catalyzed ethylene Chain-Walking polymerization

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Open Journal of Organic Polymer Materials 2024年第1期13卷 1-12页

作者： Zhengquan Dong Pei Li Guoyong Xu Fuzhou Wang Institutes of Physical Science and Information Technology School of Computer Science and Technology Anhui University Hefei China

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.

关键词： ethylene polymerization α-Diimine Ni(II) Complex Chain-Walking polymerization Branched Polyethylene

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Heterogeneousα-Diimine Nickel Catalysts with Improved Catalytic Performance in ethylene polymerization

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Chinese Journal of Chemistry 2023年第10期41卷 1155-1162页

作者： Zhanshan Ma Mengli Xu Ningning Zhu Chen Tan Changle Chen CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid Materials of Ministry of EducationKey Laboratory of Environment-Friendly Polymeric Materials of Anhui ProvinceAnhui UniversityHefeiAnhui 230601China

Heterogenization can improve the thermal tolerance of olefin polymerization catalysts and result in good product morphology con-trol,which are two important parameters for industrial polyethylene production.In this work,α-diimine nickel catalysts bearing-OH or-ONa anchoring groups were designed and prepared.The anchoring groups can enable facile heterogenization of the cata-lysts on silica.The heterogeneous catalysts demonstrated enhanced thermal stabilities,along with high catalytic activity at 120℃(up to 5.5×10^(6)g·PE·mol·Ni^(-1)·h^(-1)).Furthermore,the heterogenization process results in the improvements of many other parame-ters,including polymer morphology control,catalytic activity(up to 1.9×10^(7)g·PE·mol·Ni^(-1)·h^(-1))and polyethylene molecular weight(Mn up to 2.3×10^(6)g·mol^(-1)).More importantly,the structure and properties of the polymer products can be controlled by catalyst structures,polymerization conditions and heterogenization to achieve good mechanical properties and elasticity.

关键词： ethylene polymerization Mechanical properties Nickel Supported catalysts Heterogeneous catalysis polymerization Morphology

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Investigating the Effects of Para-methoxy Substitution in Sterically Enhanced Unsymmetrical Bis(arylimino)pyridine-cobalt ethylene polymerization Catalysts

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Chinese Journal of Polymer Science 2022年第3期40卷 266-279,I0007页

作者： Yi Yan Shi-Fang Yuan Ming Liu Gregory A.Solan Yan-Ping Ma Tong-Ling Liang Wen-Hua Sun Institute of Applied Chemistry Shanxi UniversityTaiyuan 030006China Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Sciences Institute of Chemistry Chinese Academy of SciencesBeijing 100190China Department of Chemistry University of LeicesterUniversity RoadLeicester LE17RHUK State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

A group of five bis(arylimino)pyridine-cobalt(Ⅱ)chloride complexes,[2-{(2,6-(Ph_(2)CH)_(2)-4-MeOC_(6)H_(2))N=CMe}-6-(ArN=CMe)C_5 H_(3)N]CoCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3)Co1,2,6-Et_(2)C_(6)H_(3)Co2,2,6-iPr_(2)C_(6)H_(3)Co3,2,4,6-Me_(3)C_(6)H_(2)Co4,2,6-Et_(2)-4-MeC_(6)H_(2)Co5),each containing one N-4-methoxy-2,6-dibenzhydrylphenyl group and one smaller sterically/electronically variable N-aryl group,have been synthesized in good yield(>71%)from the corresponding neutral terdentate nitrogen-donor precursor,L1-L5.All complexes have been characterized by^(1)H-NMR and FTIR spectroscopy with the former highlighting the paramagnetic nature of these cobaltous species and the unsymmetrical nature of the chelating ligand.The molecular structures of Co3 and Co4 emphasize the steric differences of the two inequivalent N-aryl groups and the distorted square pyramidal geometry about the metal centers.In the presence of MAO or MMAO,Co1-Co5 collectively displayed high activities for ethylene polymerization producing high molecular weight polyethylenes that,in general,exhibited narrow dispersities(M_w/M_n values:2.12-4.07).Notably,the least sterically hindered Co1 when activated with MAO was the most productive(6.92×10^(6)g_(PE)·mol^(-1)_((Co))·h^(-1))at an operating temperature of60℃.Conversely,the most sterically hindered Co3/MMAO produced the highest molecular weight polyethylene(M_w=6.29×10^(5)g·mol^(-1)).All the polymers displayed high linearity as demonstrated by their melting temperatures(>130℃)and their~1 H-and^(13)C-NMR spectra.By comparison of Co1 with its para-methyl,-chloro and-nitro counterparts,the presence of the para-methoxy substituent showed the most noticeable effect of enhancing the thermal stability of the catalyst.

关键词： Cobalt(II)precatalyst ethylene polymerization High molecular weight polyethylene Electronic effects Thermal stability

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A general cocatalyst strategy for performance enhancement in nickel catalyzed ethylene(co)polymerization

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Chinese Chemical Letters 2022年第9期33卷 4363-4366页

作者： Quan Wang Zhao Zhang Chen Zou Changle Chen CAS Key Laboratory of Soft Matter Chemistry Department of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

The tuning of olefin-polymerization catalyst properties through ligand modifications is efficient but requires complicated and costly syntheses.In this contribution,a simple Bu_(2)Mg-based cocatalyst strategy is designed that can simultaneously enhance the catalytic properties(activity,thermal stability,polymer molecular weight,branching density,melting point,etc.)of various nickel catalysts(α-diimine nickel,pyridine imine nickel and iminopyridine-N-oxide nickel)in ethylene polymerization,and enable great product morphology control.For example,a simpleα-diimine nickel catalyst can demonstrate polymerization activity of up to 1.29×10^(7)g mol^(−1)h^(−1)and molecular weight of up to 1.90×10^(6)g/mol in the presence of Bu_(2)Mg cocatalyst.The resulting polyethylenes exhibit excellent mechanical properties,with tensile stress of up to 47.4 MPa and strain of up to 1020%.This cocatalyst strategy is generally applicable to different nickel catalysts,and can lead to property enhancement in ethylene copolymerization with a series of polar comonomers such as methyl 10-undecylenate,10-undecylenic acid and 10-undecenol.

关键词： Nickel Cocatalyst Magnesium ethylene polymerization

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Promoting ethylene (co)polymerization in Aliphatic Hydrocarbon Solvents Using tert-Butyl Substituted Nickel Catalysts

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Chinese Journal of Chemistry 2022年第2期40卷 215-222页

作者： Ao Chen Daohong Liao Changle Chen Hefei National Laboratory for Physical Sciences at the Microscale CAS Key Laboratory of Soft Matter ChemistryDepartment of Polymer Science and EngineeringUniversity of Science and Technology of ChinaHefeiAnhui 230026China

In the past few decades,the development of high-performance catalysts has been a key driving force and a center of research efforts in the field of olefin polymerization.However,a major discrepa ncy exists between in dustrial researches which utilize aliphatic hydrocarb on solventsz and academic researches which predominantly focus the catalytic properties in aromatic solvents.In this con-tribution,a novel diaryl-methyl aniline bearing eight tert-butyl groups was prepared and subsequently transformed to four different kinds of imine-type ligands.The corresponding nickel complexes as well as their counterparts derived from diphenyl-methyl aniline without the tert-butyl groups were prepared and investigated in ethylene polymerization.

关键词： ethylene polymerization Polyethylene Nickel Solvent effects Steric hindranee

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High-Performanceα-Diimine Nickel Complexes for Facile Access of PE Elastomers with Exceptional Material Properties

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Chinese Journal of Polymer Science 2024年第5期42卷 620-635,I0008页

作者： Li-Dong Qin Xin-Yu Wang Qaiser Mahmood Zhi-Xin Yu Yi-Zhou Wang Song Zou Tong-Ling Liang Wen-Hua Sun School of Pharmaceutical Sciences Changchun University of Chinese MedicineChangchun130117China Chemistry and Chemical Engineering Guangdong Laboratory Shantou515031China Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China

For practicable elastomeric polyethylene,achieving high catalyst thermal stability and activity,along with precise control of polymer properties such as branching density,molecular weights,and distribution,is crucial but challenging.In this study,two sets of symmetricalα-diimine nickel complexes,each comprising four nickel bromide or chloride complexes,were synthesized and investigated their performance for ethylene polymerization under various reaction conditions.Upon activation with either Et2AlCl or MMAO cocatalysts,these complexes displayed not only high activity but also generated high molecular weight polyethylenes with controlled polydispersity and a substantial number of branches.The catalyst with the least steric hindrance displayed the remarkable high activity(up to 1.2×10^(7) g·mol^(-1)·h^(-1)).Notably,nickel bromides demonstrated higher activity compared to their chloride counterparts.The investigation into the effect of reaction temperature on catalytic performance revealed that NiBrMe-MMAO system displayed high thermal stability(activity up to 2.51×10^(6) g·mol^(-1)·h^(-1) at 100℃)and consistently yielded high polymer molecular weights with narrow polydispersity over a broad temperature range of 30-100℃.Of significant note,mechanical analysis of the resulting polyethylene demonstrated excellent ultimate tensile strength and high strain at break.Particularly,the polyethylene sample prepared at 100℃exhibited ultimate tensile strength up to 10 MPa with 1863%maximum strain at break and a strain recovery of up to 54.9%after ten cycles at a fixed strain of 300%,indicating excellent material properties of prepared thermoplastic polyethylene elastomers(TPE).

关键词： Thermoplastic polyethylene elastomers α-Diimine nickel pre-catalysts ethylene polymerization Mechanical properties Highly branched polyethylene

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ethylene polymerization by a Novel Dinuclear Heter-oligated Titanium Complex with the Ligand of (Salicylaldiminato) (β-enaminoketonato)

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Journal of Wuhan University of Technology(Materials Science) 2008年第6期23卷 821-824页

作者：聂玉静孙俊全 Department of Chemical Engineering Institute of United Chemical Reaction Engineering College of Material and Chemical EngineeringZhejiang University

The condensation of acetylacetone （CH3COCH2COCH3） with benzdine （H2N-C6H4-C6H4-NH2） yielded diimine ligand 1 [HOC（Me）C（H）（Me）C=N（p-C6H4）（C6H4-p）N= C（Me）C（H）C（Me）OH）], which was converted into sodium salts. And then the sodium salts reacted with monosalicylaldiminato titanium complex 2{[3,5-di-But′2-（O）C6H2CHN（PH）]TiCl3（THF）} in dried dichloromethane to give a new benzdine-bridged binuclear complex 3{[3,5-di-Bu′-2-（O）C6H2CHN（PH）]2 [OC（Me）C（H）（Me）C=N（p-C6H4）-（C6H4-p）N=C（Me）C（H） C（Me）]Ti2Cl4}. The complex 3 was characterized by ^1HNMR and elemental analysis. In the presence of MAO（methylaluminoxane）, the complex 3 in toluene was effective to catalyze polymerization, affording moderately high catalytic activity 1.93 × 10^5 g PE/（mol.Ti.h）]and high molecular weight polyethylene [5.63× 10^5 g/moll. The high temperature gel permeation chromatography （GPC） curve of polyethylene obtained revealed a single peak, but the molecular weight distribution （MWD = 3.21） is obviously broader than that of the similar mononuclear titanium complex. The melting points of the obtained polyethylene reaches 138 ℃, indicating that the polyethylene is of high crystallinity.

关键词： ethylene polymerization titanium complex binuclear

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