Field Of Olefin Polymerization Research Articles

Ammonium Tetrakis(pentafluorophenyl)borate: Preparation and Application in Olefin Coordination Polymerization as the Cocatalyst Compound.

Metallocene catalysts have attracted much attention from academia and industry for their excellent catalytic activity in the field of olefin polymerization. Cocatalysts play a key role in metallocene catalytic systems, which can not only affect the overall catalytic activity, but also have an obvious influence on the structure and properties of the polymer. Although methylaluminoxane (MAO) is currently the most widely used cocatalyst, its price increases the production cost of polyolefin materials. Ammonium tetrakis(pentafluorophenyl)borate has shown excellent performance in polymerization, being one of the best substitutes for the traditional cocatalyst MAO. Compared with the main catalyst, whose composition and structure are relatively complex, the research on cocatalyst is very limited. This review mainly introduces the research history, preparation methods, and application progress in polymerization of ammonium tetrakis(pentafluorophenyl)borate, deepening our understanding of the role of cocatalyst in polymerization, with the hope of inspiring brand-new thinking on improving and enhancing the overall performance of catalyst systems.

Double stimulus-responsive palladium catalysts for ethylene polymerization and copolymerization

The external stimulus response strategy has been evolved rapidly in the field of olefin polymerization. In this work, we modularly synthesized three types of double stimulus responsive α-diimine palladium catalysts, combining redox regulation and other regulation together, such as light, Lewis acid and alkali cations. The catalytic activities and the molecular weight of polyethylene products can be regulated for 4 times in ethylene polymerization. These palladium complexes were also used for the copolymerization reaction of ethylene and polar monomers, such as methyl 10-undecylenate and methyl acrylate, effectively regulating the catalytic activities, the molecular weight and polar monomer incorporation of the prepared copolymers. The research on these dual-regulated palladium complexes makes full use of prepared catalysts and provides new inspirations for regulating olefin polymerization.

Promoting Ethylene (co)Polymerization in Aliphatic Hydrocarbon Solvents Using tert‐Butyl Substituted Nickel Catalysts

Comprehensive SummaryIn 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 discrepancy exists between industrial researches which utilize aliphatic hydrocarbon solvents, and academic researches which predominantly focus the catalytic properties in aromatic solvents. In this contribution, 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. The multiple tert‐butyl groups enable great solubility of the metal complexes in aliphatic hydrocarbon solvents, leading to similar polymerization properties comparing with aromatic solvents. In contrast, their counterparts without tert‐butyl groups demonstrate significant solvent effect. Moreover, the ligand electronic and steric effects induced by the tert‐butyl groups lead to nickel catalysts with great thermal stability (up to 140 oC) and capabilities of generating high molecular weight polymer and copolymer products. This tert‐butyl strategy can be potentially applied to many different polymerization catalyst systems and help to bridge academic studies with practical applications.

Synthesis of mononuclear and dinuclear palladium (II) complexes containing oxadithioether ligands and their catalytic activities in norbornene polymerization

AbstractThe Pd (II) complexes trans‐[PdCl2(μ‐L)]2 and [Pd(acac)(L)][BF4] (L = RS(CH2)2O(CH2)2SR, R = Me, Et, nPr, iPr, nBu, iBu, n‐hexyl, benzyl) were obtained through the reaction of Pd(cod)Cl2 or [Pd(acac)(MeCN)2][BF4] with one equivalent of oxadithioether (L). The structural features of these complexes were analyzed by nuclear magnetic resonance (NMR) and Fourier‐transform infrared spectroscopy (FTIR), as well as electrospray ionisation mass spectrometry and density functional theory calculations. The complexes di‐μ‐(2,10‐dimethyl‐6‐oxa‐3,9‐dithiaundecane‐κ2S,S′)‐bis[trans‐dichloropalladium (II)] and (acetylacetonate‐κ2O,O′)(2,10‐dimethyl‐6‐oxa‐3,9‐dithiaundecane‐κ2S,S′)palladium (II) tetrafluoroborate were characterized by X‐ray diffractometry. The X‐ray structures of each complex indicate an axial M–O interaction formed by the endodentate conformation of the oxadithioether ligand. Palladium (II) dichloride complexes with oxadithioethers were demonstrated to have a 16‐membered dinuclear structure with a trans‐configured S2PdCl2 fragment. In the case of cationic palladium acetylacetonate complexes, only mononuclear complexes with a cis configuration of the oxadithioether fragment were observed. Variable temperature 1H and 13C NMR studies of the complexes demonstrate dynamic bonding of the oxadithioether ligands consistent with the presence of diastereoisomers that differ in the orientation of the S‐R groups along with both endodentate and exodentate bonding modes in solution. FTIR studies of the complexes indicate the presence of isomers in the solid state. The palladium catalyst precursors trans‐[PdCl2(μ‐L)]2 and [Pd (acac)(L)][BF4] were found to be active in the addition polymerization of norbornene. In the presence of cocatalysts, such as diisobutylaluminum chloride and boron trifluoride etherate, Pd (II) complexes exhibited activities in the range of 105 to 107 g of polymer (mol of Pd)−1 h−1. The catalyst systems showed good thermostability with a high activity of 1.43 × 107 g of polymer (mol of Pd)−1 h−1 at 75°C. These complexes are examples of Pd (II) complexes bearing thioether ligands, which are rarely observed in the field of olefin polymerization.

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

Highly efficient incorporation of polar comonomers in copolymerizations with ethylene using iminopyridyl palladium system

Given that high-molecular-weight functionalized polyethylene with high polar monomer incorporation ratio are often difficult to achieve, the development of highly efficient catalysts for ethylene and polar monomer copolymerization is still an urgent need in the field of olefin polymerization. In this contribution, we developed a series of highly sterically hindered iminopyridyl Pd(II) catalysts bearing the 8-aryl naphthyl substituents or/and dibenzosuberyl substituents. These substituents can provide an effective shield on the axial sites of the active center, thus allowing for the formation of high-molecular-weight polyethylene or functionalized polyethylene. Unexpectedly, these catalysts were also highly efficient for ethylene and various polar monomers copolymerization, giving access to high-molecular-weight functionalized polyethylene with very high incorporation ratio (up to 24%). The unique structure of the iminopyridyl ligand, especially its ability to shield the axial binding sites, may lead to permitting an adequate incorporation of polar monomers in our system.

Amidine/Phosphine‐Oxide‐Based Nickel Catalysts for Ethylene Polymerization and Copolymerization

AbstractNickel catalyzed copolymerization of olefins with polar co‐monomers remains a great challenge in the field of olefin polymerization. In this contribution, a series of amidine/phosphine‐oxide‐based ligands were synthesized and investigated for nickel catalyzed ethylene polymerization and copolymerization with polar co‐monomers. These nickel catalysts exhibited high catalytic activities (homopolymerization: up to 2.6×106 g (mol of Ni)−1 h−1; copolymerization: up to 1.0×105 g (mol of Ni)−1 h−1;) and good thermal stabilities at 80 °C, generating high‐molecular‐weight polyethylenes (Mn up to 8.45×104 g mol−1) as well as copolymers (Mn up to 2.19×104 g mol−1). The Ni center exhibited square planar geometry. The N atom between the imine and phosphine‐oxide moieties exhibited trigonal planar geometry, indicating electron‐donating conjugate effect of the sp2 hybrid N‐atom linker. This electronic effect can increase the electron density on the nickel center and result in enhanced catalytic performance.

A Versatile Ligand Platform for Palladium- and Nickel-Catalyzed Ethylene Copolymerization with Polar Monomers.

The ability to carry out transition-metal-catalyzed copolymerizations of olefins with polar monomers is a great challenge in the field of olefin polymerization. Palladium has been the dominant player in this field, while its low-cost nickel counterpart has only achieved very limited success. We report the synthesis and evaluation of a highly versatile platform based on diphosphazane monoxide ligands. Both palladium and nickel catalysts bearing these ligands mediate the copolymerization of ethylene with a number of fundamental polar monomers.

A Versatile Ligand Platform for Palladium‐ and Nickel‐Catalyzed Ethylene Copolymerization with Polar Monomers

AbstractThe ability to carry out transition‐metal‐catalyzed copolymerizations of olefins with polar monomers is a great challenge in the field of olefin polymerization. Palladium has been the dominant player in this field, while its low‐cost nickel counterpart has only achieved very limited success. We report the synthesis and evaluation of a highly versatile platform based on diphosphazane monoxide ligands. Both palladium and nickel catalysts bearing these ligands mediate the copolymerization of ethylene with a number of fundamental polar monomers.

Influence of Polyethylene Glycol Unit on Palladium- and Nickel-Catalyzed Ethylene Polymerization and Copolymerization.

The transition-metal-catalyzed copolymerization of olefins with polar functionalized co-monomers represents a major challenge in the field of olefin polymerization. It is extremely difficult to simultaneously achieve improvements in catalytic activity, polar monomer incorporation, and copolymer molecular weight through ligand modifications. Herein we introduce a polyethylene glycol unit to some phosphine-sulfonate palladium and nickel catalysts, and its influence on ethylene polymerization and copolymerization is investigated. In ethylene polymerization, this strategy leads to enhanced activity, catalyst stability, and increased polyethylene molecular weight. In ethylene copolymerization with polar monomers, improvements in all copolymerization parameters are realized. This effect is most significant for polar monomers with hydrogen-bond-donating abilities.

Influence of Polyethylene Glycol Unit on Palladium‐ and Nickel‐Catalyzed Ethylene Polymerization and Copolymerization

AbstractThe transition‐metal‐catalyzed copolymerization of olefins with polar functionalized co‐monomers represents a major challenge in the field of olefin polymerization. It is extremely difficult to simultaneously achieve improvements in catalytic activity, polar monomer incorporation, and copolymer molecular weight through ligand modifications. Herein we introduce a polyethylene glycol unit to some phosphine‐sulfonate palladium and nickel catalysts, and its influence on ethylene polymerization and copolymerization is investigated. In ethylene polymerization, this strategy leads to enhanced activity, catalyst stability, and increased polyethylene molecular weight. In ethylene copolymerization with polar monomers, improvements in all copolymerization parameters are realized. This effect is most significant for polar monomers with hydrogen‐bond‐donating abilities.

ChemInform Abstract: Redox Control in Olefin Polymerization and Copolymerization

AbstractReview: [23 refs.

Redox Control in Olefin Polymerization and Copolymerization

In the field of olefin polymerization, catalyst modification remains the prevalent strategy to control the polymerization and copolymerization processes. The development of alternative strategies is, nevertheless, highly fascinating. Here, the concept of redox-controlled polymerization and its applications in the ring-opening polymerization of cyclic ester type monomers is presented. Early work on the introduction of the redox-control concept into the field of olefin polymerization is described, and our approach to address the early issues and realize redox controlled olefin polymerization and copolymerization is demonstrated. Finally, some conclusions and perspectives are discussed. 1 Introduction 2 The Concept of Redox Control in Polymerization 3 Early Work on Redox Control in Olefin Polymerization 4 Our Approach to Realize Redox-Controlled Olefin (Co)Polymerization 5 Conclusions and Perspectives

Postep badan w zakresie polimeryzacji olefin

Postep badan w zakresie polimeryzacji olefin

後周期遷移金属錯体触媒によるオレフィン重合 最近の研究動向

This review summarizes the recent developments in the field of olefin polymerization, especially focuses on the topic by nickel, palladium, iron, cobalt, and ruthenium complex catalysts including the brief summary of this research background. A lot of studies have been explored concerning olefin polymerization by nickel and palladium complex catalysts especially after the discovery of α-diimine coordinated nickel and palladium catalysts reported by Brookhart et al., and these results introduce new possibilities for making new type of olefin-based copolymers by these catalysts. In particular, recent discovery concerning ethylene polymerization by iron and cobalt complexes containing 2, 6-bis (imino) pyridine ligand attracted particular attention due to the exceptionally high catalytic activity, and the contents concerning this topic have also been summarized briefly. We also wish to introduce our recent results concerning olefin polymerization by ruthenium and iron complexes-cocatalyst systems.

Supported metallocene catalysts with MAO and boron activators

Metallocene catalysts have had a significant impact in the field of olefin polymerization over the last years. This article describes how the metallocenes made it from a laboratory curiosity to industrial scale applications. A major breakthrough was the development of suitable supporting techniques that allow the adaptation of this new generation of catalysts to large scale heterogeneous polymerization reactors.

The Role of MgCl2as Supporter for the New Generation of Olefin Polymerization Catalysts

Abstract Most of the research in the field of olefin polymerization is focused on TiC1, catalysts on a specially prepared MgCl, support. In order to combine a high polymer yield with good stereoselectivity, a complexed cocatalyst is used. Most frequently it is a mixture of AIEtzCl or AlEt, with an electron donor such as tetrahydrofuran (THF) or ethyl benzoate for ethylene and propylene polymerization, respectively.

Recent advances in the polymerisation of propylene

Since its discovery, the field of olefin polymerization using Ziegler-Natta catalysts has undergone rapid development both in terms of industrial catalysis as well as fundamental understanding of this polymerization process. This paper reviews some aspects of the recent developments with specific regard to propylene polymerizations.