Copolymerization Of Carbon Monoxide Research Articles

Recent Advances in Synthesis of Non-Alternating Polyketone Generated by Copolymerization of Carbon Monoxide and Ethylene.

The copolymers of carbon monoxide (CO) and ethylene, namely aliphatic polyketones (PKs), have attracted considerable attention due to their unique property and degradation. Based on the arrangement of the ethylene and carbonyl groups in the polymer chain, PKs can be divided into perfect alternating and non-perfect alternating copolymers. Perfect alternating PKs have been previously reviewed, we herein focus on recent advances in the synthesis of PKs without a perfect alternating structure including non-perfect alternating PKs and PE with in-chain ketones. The chain structure of PKs, catalytic copolymerization mechanism, and non-alternating polymerization catalysts including phosphine-sulfonate Pd, diphosphazane monoxide (PNPO) Pd/Ni, and phosphinophenolate Ni catalysts are comprehensively summarized. This review aims to enlighten the design of ethylene/CO non-alternating polymerization catalysts for the development of new polyketone materials.

Nickel-Catalyzed Selective Incorporation of Isolated In-Chain Carbonyls into Ethylene/Carbon Monoxide Copolymer Using Metal Carbonyls as a Carbonyl Source

Abstract Non-alternating copolymers of ethylene and carbon monoxide were obtained by nickel-catalyzed polymerization of ethylene in the presence of Fe2(CO)9 as a carbon monoxide source. Higher selectivity to isolated ketone group than the previously reported nickel-catalyzed systems, while having a higher catalytic activity than the palladium catalysts in our previous report has been achieved. Furthermore, various P-stereogenic phosphine-phenolate ligands were developed to investigate the effect of ligand structure on the copolymerization. Finally, the degradability of the resulting polymer was evaluated.

Controlled Cobalt-Mediated Free-Radical Co- and Terpolymerization of Carbon Monoxide.

While controlled free-radical polymerizations are established for a vast range of vinyl monomers, they have not been reported for carbon monoxide, although it is a unique monomer that forms in-chain keto groups which can promote, for example, desirable photo-degradability in polyethylenes. We report organometallic-mediated radical copolymerization of carbon monoxide with ethylene initiated by an organocobaltIII compound to keto-modified polyethylenes with up to 15 mol % ketone repeat units. Terpolymerization with 2-methylene-1,3-dioxepane affords polyethylenes with in-chain ester and keto groups. Compared to ethylene homopolymerization, the controlled character of the copolymerization is strongly enhanced by the Lewis base function of carbon monoxide, which suppresses multiple unfavorable termination pathways.

Alternating copolymerization of carbon monoxide and vinyl arenes using [N,N] bidentate palladium catalysts

AbstractThe alternating copolymers of carbon monoxide (CO) and vinyl arene monomers, namely aromatic polyketones, are a family of attractive engineering plastic. In the catalytic synthesis of this kind of polymeric materials, [N,N] bidentate palladium catalysts represent the most successful catalytic systems. In this review, we introduce the present status of polyketone synthesis, with a focus on the aromatic polyketones made from vinyl arene and CO. We also address the palladium‐catalyzed CO/vinyl arene alternating copolymerization mechanism. A variety of [N,N] bidentate palladium catalysts bearing 2,2′‐bipyridine, 1,10‐phenanthroline, α‐diimine, and pyridine‐imine ligands are surveyed for CO/vinyl arene copolymerization. The effects of vinyl arene monomer, counteranion, and solvent on copolymerization are also discussed. The copolymerization stereochemistry including chain end‐control and enantiomorphic site control mechanisms is introduced. This review aims to promote the design of [N,N] bidentate palladium catalysts for CO/vinyl arene copolymerization for the development of high‐performance aromatic polyketones.

Palladium Promoted Copolymerization of Carbon Monoxide with Polar or Non-polar Olefinic Monomers

The copolymers of carbon monoxide (CO) and olefins, namely polyketones, are a family of widely used materials. In the catalytic preparation of these materials, palladium(II) catalysts represent the most successful catalytic systems. The production of both alternating and non-alternating polyketones has been achieved, with a great difference in their physical properties. Herein, a variety of palladium(II) catalysts, employed for the copolymerization of CO with various olefinic monomers, such as ethylene, α -olefins, styrene and polar vinyl monomers, are fully summarized. The influence of important factors, such as solvents and counterions on specific copolymerization, is also discussed. This review aims to enlighten the design of new Pd catalysts with improved properties, as well as the development of new polyketone materials.

Selective, Catalytic Oxidations of C–H Bonds in Polyethylenes Produce Functional Materials with Enhanced Adhesion

Summary The synthesis of functional and processable polyethylenes from simple vinyl monomers with controlled molecular weights and architectures has been a grand challenge of polymer chemistry. Post-polymerization modification of the homopolymers of ethylene is attractive for this purpose but has been hampered by the lack of efficient methods for the selective functionalization of C–H bonds in polyolefins. We report the selective, catalytic oxidation of C–H bonds in commodity polyethylenes with varying molecular weights and architectures. Remarkably, the functionalized materials, even at low levels of functionalization, exhibit physical properties that are absent in unmodified polyolefins, such as strong adhesion and the ability to be painted with common waterborne latex paint. Such observations indicate that selectively modified polyethylenes as described here may help to transform existing commodity plastics into more valuable and potentially more sustainable materials.

Photodegradable branched polyethylenes from carbon monoxide copolymerization under benign conditions

Small amounts of in-chain keto groups render polyethylene (PE) photodegradable, a desirable feature in view of environmental plastics pollution. Free-radical copolymerization of CO and ethylene is challenging due to the formation of stable acyl radicals which hinders further chain growth. Here, we report that copolymerization to polyethylenes with desirable low ketone content is enabled in dimethyl carbonate organic solvent or under aqueous conditions at comparatively moderate pressures <350 atm that compare favorable to typical ethylene polymerization at 2000 atm. Hereby, thermoplastic processable materials can be obtained as demonstrated by injection molding and tensile testing. Colloidally stable dipersions from aqueous polymerizations form continuous thin films upon drying at ambient conditions. Extensive spectroscopic investigation including 13C labeling provides an understanding of the branching microstructures associated with keto groups. Exposure of injection molded materials or thin films to simulated sunlight under sea-like conditions results in photodegradation.

Enhancement on Alternating Copolymerization of Carbon Monoxide and Styrene by Dibenzobarrelene-Based α-Diimine Palladium Catalysts

CO/styrene copolymerization by α-diimine palladium catalysts is a promising method for direct synthesis of polyketones. The effect of the catalyst backbone structure on CO/styrene copolymerization has been studied with the aim of developing robust α-diimine palladium catalysts able to improve the polymerization productivity and controllability. Dibenzobarrelene derived α-diimine palladium catalysts without o-aryl substituents were designed and synthesized for CO/styrene alternating copolymerization. Introduction of the rigid and bulky dibenzobarrelene backbone enhanced the thermal stability and the productivity of palladium catalyst. The dibenzobarrelene ligand backbone also improved the polymerization controllability, and living CO/styrene copolymerizations were achieved at 15 °C using α-diimine palladium catalysts in CH2Cl2. The steric hindrance of backbone and the π–π stacking between the dibenzobarrelene backbone and the aniline played crucial roles in stereocontrol and productivity.

Zwitterionic Design Principle of Nickel(II) Catalysts for Carbonylative Polymerization of Cyclic Ethers

AbstractZwitterionic structure is necessary for NiII complexes to catalyze carbonylative polymerization (COP) of cyclic ethers. The cationic charge at the NiII center imparts sufficient electrophilicity to the Ni–acyl bond for it to react with cyclic ethers to give an acyl‐cyclic ether oxonium intermediate, while the ligand‐centered anionic charge ensures that the resultant oxonium cation is ion‐paired with the Ni0 nucleophile. The current catalysts give non‐alternating copolymers of carbon monoxide and cyclic ethers and are the most effective when both ethylene oxide and tetrahydrofuran are present as the cyclic ether monomers.

Zwitterionic Design Principle of Nickel(II) Catalysts for Carbonylative Polymerization of Cyclic Ethers.

Zwitterionic structure is necessary for NiII complexes to catalyze carbonylative polymerization (COP) of cyclic ethers. The cationic charge at the NiII center imparts sufficient electrophilicity to the Ni-acyl bond for it to react with cyclic ethers to give an acyl-cyclic ether oxonium intermediate, while the ligand-centered anionic charge ensures that the resultant oxonium cation is ion-paired with the Ni0 nucleophile. The current catalysts give non-alternating copolymers of carbon monoxide and cyclic ethers and are the most effective when both ethylene oxide and tetrahydrofuran are present as the cyclic ether monomers.

Dependence of the Thermodynamic Characteristics of a Carbon Monoxide–Ethylene–Butene-1 Copolymer on the Concentration of Butane Fragments in the Macromolecules

The heat capacity, temperatures and enthalpies of the physical transformations of a triple alternating copolymer of carbon monoxide with ethylene and butene-1 with a 46 mol % concentration of butane fragments are studied via adiabatic and differential scanning calorimetry in the region of 6−570 K. Its combustion energy in a condensed state at T = 298.15 K is measured calorimetrically. Standard thermodynamic functions of the copolymer in the region of T → 0 to 400 K and the thermodynamic characteristics of its formation at T = 298.15 K and synthesis within the range of T → 0 to 400 K are calculated. The dependences of the thermodynamic properties of the copolymer on the concentration of butane fragments in the macromolecules are obtained.

New Ion-Exchange Membranes Derived from Polyketone

The centre piece at the heart of numerous energy storage and conversion devices, such as fuel cells and redox flow batteries, is the ion-exchange membrane (IEM). This typically polymeric material is responsible for the migration of ionic species, separation of fuel stocks and for providing additional support to the electrode assemblies. As a result, IEMs are required to possess excellent stability (both thermal and chemical), long lifetimes, electrical insulation, and high ionic conductivity and specificity. Current state-of-the-art polymer electrolytes possessing the more desirable properties tend to come with a price tag that can render their use in energy storage/conversion technologies somewhat cost prohibitive [1]. This has created a strong driving force aimed towards new, cheaper but still high performing materials, for use in energy storage/exchange systems. The copolymerization of carbon monoxide and ethylene (two readily available and cheap feedstocks) leads to the formation of polyketone, a high performance thermoplastic that has found many applications resulting in its global production of thousands of tonnes per annum. The alternating 1,4-dicarbonyl functionality of aliphatic polyketone enables access, via classic Paal-Knorr chemistry, to a variety of new functionalized polymers [2]. Here we present a new ion conducting polymeric material derived from polyketone, that possess N-functionalized pyrrole units in the backbone (FPK) [3]. Ion-conductivities on the order of 10.6 and 8.6 mScm-1 for the hydroxide and iodide forms of methylated FPKs have been achieved at 80 oC, with the hydroxide FPK demonstrating high resistance towards alkaline conditions for over 20 hours at 80 oC. The flexibility in the choice of the N-substituent renders these new materials higher tailorable and potentially useful in a range of energy storage/conversion technologies as either proton or anion exchange membranes. Acknowledgements The authors wish to thank the Strategic Project of the University of Padova “Materials for Membrane-Electrode Assemblies to Electric Energy Conversion and Storage Devices (MAESTRA)” for funding. V.D.N. thanks the University Carlo III of Madrid for granting him the “Catedra de Excelentia” (Chair of Excellence).

Crystal polymorphism of polylactides and poly(Pro-alt-CO): The metastable beta and gamma phases. Formation of homochiral PLLA phases in the PLLA/PDLA blends

Among the various crystalline phases of polylactides, an elusive orthorhombic gamma phase (γPLLA) had been obtained so far only by epitaxial crystallization on hexamethylbenzene. A recent work by J. Shao et al. (Macromolecules, 2013, 46, 6933) reports on two “novel modified crystallites” of PLLA obtained “under the confinement of stereocomplex PLLA/PDLA crystallites” produced on cooling blends of PLLA and PDLA from the melt at specific rates. These novel modified crystallites are metastable and transform to the stable αPLLA on heating. Reinterpretation of Shao et al.'s DSC and X-ray data suggests that one novel modified crystallite is the elusive γPLLA. The second form could be a disordered hexagonal phase that blends PDLA and PLLA three-fold helices, although the structural evidence is less compelling. In a parallel line of analysis, a crystal modification of the related alternating copolymer of propene and carbon monoxide (poly(Pro-alt-CO)) described as an orthorhombic structure very similar to γPLLA by Anokhin et al. (Polymer Science, Ser. A, Vol. 46, No. 1, 2004, pp. 52–60) must be reinterpreted as a trigonal frustrated phase, a phase that has already been observed in single crystals of this polymer.

Design and synthesis of 4,4′-disubstituted-[2,2′]-bipyridines for catalyzing CO/styrene copolymerization with palladium(II)

A series of 4,4’-disubstituted-[2,2’]-bipyridines, featuring electron withdrawing/donating functional groups such as amino, chloro, nitro, ethoxycarbonyl, carboxy, methyl, methoxy and hydroxymethyl, have been synthesized and employed in the copolymerization of carbon monoxide(CO)and styrene. The available bipyridine and its derivatives were coordinated with palladium(II)acetate for catalyzing the copolymerization of CO and styrene, and the concomitant polyketone was characterized by means of 13C NMR, FTIR, differential scanning calorimetry( DSC)and element analysis techniques concerning its structure and thermal performance. The effect of different electron-donating and electron-withdrawing groups on catalyst performance and molecular weight of copolymer was studied under certain experimental condition. It has been proved that the enhancement of electron donating and conjugative effects on bipyridine ligand will not only improve the catalytic activity of the composition, but also increase the molecular weight of the as-prepared polyketone. The catalytic activity is the highest in hydroxymethyl substituted 2,2’-bipyridine ligand(1 356 gSTCO/(gPd · h)), when the molecular weight and polydispersity index of the polyketone are M n=8 502,M w=1 3440 and M w/M n=1.581, respectively.

Effects of finishing conditions on the properties of polyketone fiber

Polyketone fiber, a newly developed super fiber, is available by copolymerization of carbon monoxide and unsaturated hydrocarbon monomer, ethylene. Because of its high mechanical properties and good adhesion with rubber materials, it can be applied for the reinforcement of mechanical rubber goods (MRG) such as tires, hoses and protective gloves. In this study, the mechanical property changes of polyketone fiber as finishing treatment (drawing, annealing, and sizing) were investigated. Drawing of polyketone fiber was conducted from 1.2 to 2.0 times at 180 °C and its annealing was conducted from 120 to 200 °C at draw ratio of 1.8, respectively. As subsequent results, the sizing treated polyketone fibers have a higher tensile strength and modulus due to the surface protection effect. Especially, the drawing treatment has more influence on the tensile modulus of a fiber, while the annealing does on the tensile strength.

Synthesis of polyketone by copolymerization of styrene and CO using carbon nanotube-complex Pd2+ catalyst

The dipping method was devised to deposit Pd onto carbon nanotube as supported catalyst (Pd/CNT) for the copolymerization of carbon monoxide (CO) and styrene(ST) towards the formation of polyketone (PK). The Pd/CNT was characterized by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The construction and crystallization property of PK were evaluated by Fourier transform infrared spectroscopy (FTIR), 13C-nuclear magnetic resonance(NMR) and XRD, respectively. The catalyst showed excellent activity and reusability in promoting the fabrication of PK. It can be recycled 14 times with the highest total catalytic activity of 4 239.64 gPK/ (gPd·h) at Pd content of 8.63wt%. The results indicate that the prepared catalyst is effective to catalyze the copolymerization of CO and styrene.

Mechanical and thermal properties of ternary alternating copolymers of carbon monoxide with olefins

Thermal properties and the deformational behavior of ternary alternating copolymers of carbon monoxide with ethylene and other olefins (propylene, 1-butene, styrene) with molecular masses of Mn = 1000–35000 and molar fraction of the third comonomer in the polymer chain from 0.02 to 0.70 were investigated. Temperatures of melting and glass transition are significantly affected by the composition of the products. Varying the nature of the third comonomer or the content of its units in the polymer chain and the molecular masses of terpolymers makes it possible to obtain materials with Young’s moduli of 0.003–3.090 GPa and elongations at break of 5–2000%.

Polyoximes based on the alternating carbon monoxide copolymers

A new efficient method for the synthesis of polyoximes was developed based on the oximation of the alternating carbon monoxide copolymer with ethylene or styrene in the polar aprotic solvent.

Ethylene and Styrene Carbon Monoxide Copolymerization Catalyzed by Pyrazolyl Palladium(II) Complexes

The pyrazolyl pyridylimine ligands [2-(3,5-dimethylpyrazol-1-yl)ethyl]pyridin-2-ylmethyleneimine (L1) and [2-(3,5-di-tert-butylpyrazol-1-yl)ethyl]pyridin-2-ylmethyleneimine (L2) and pyrazolyl thienylimine ligands [2-(3,5-dimethylpyrazol-1-yl)ethyl]thiophen-2-ylmethyleneimine (L3), [2-(3,5-di-tert-butyl-pyrazol-1-yl)ethyl]thiophen-2-ylmethyleneimine (L4), [2-(3,5-dimethylpyrazol-1-yl)ethyl]-2-bromothiophen-2-ylmethyleneimine (L5), and [2-(3,5-di-tert-butyl-pyrazol-1-yl)ethyl]-2-bromothiophen-2-ylmethyleneimine (L6) were synthesized by condensation of the appropriate pyrazolylamine and the corresponding aldehyde. Reactions of L1–L6 with [PdCl(Me)(cod)] gave the corresponding palladium(II) complexes [PdCl(Me)(L)] (where L = L1 (1a), L2 (2a), L3 (3a), L4 (4a), L5 (5a), L6 (6a)) in very good yields. The pyridylimine ligands L1 and L2 were found to coordinate via the imine and pyridine nitrogen atoms, while the thienylimine ligands L3–L6 coordinate via imine and pyrazolyl nitrogen atoms to the palladium. The ca...

Influence of formic acid and water on the [Pd(OAc)2(dppp)] catalyzed ethene–carbon monoxide copolymerization carried out in aprotic organic solvents

The copolymerization of ethene with carbon monoxide catalyzed by [Pd(OAc)2(dppp)] in an aprotic solvent such as 1,4-dioxane or nitromethane is efficiently promoted both by H2O and HCOOH and yields a perfectly alternating polyketone (PK). The influence of the concentration of the promoters, pressure and temperature on the catalyst productivity and the limiting viscosity number (LVN) has been studied. The productivity increases with the increase of temperature and pressure. The LVN increases upon increasing the pressure and lowering the temperature. At 363K and 9.0MPa, in HCOOH/H2O/1-4,dioxane (2.7/1.35/1 molar ratio), the productivity is 37.50kgPK(gPdh)−1 (LVN 2.77dLg−1).LVN lowers upon increasing the concentration of the acid, suggesting that it is involved in the protonolysis chain-transfer process.