Compositional Relationships in the Copolymerization of Ethylene with Carbon Monoxide

Coffman, D. D.; Pinkney, P. S.; Wall, Frederick T.; Wood, William H.; Young, Howard S.

doi:10.1021/ja01133a051

Cited by 49 publications

(18 citation statements)

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“…[4] Since 2002, it was reported that the use of Pd[P-O] catalysts enables successive insertion of several ethylene units into the growing polyketone chain for the synthesis of non-perfectly alternating copolymerization of CO and ethylene. [14,15] Although al ow content of CO was used in these cases,t he obtained polyketones still contained significant alternating units which showed strong interchain dipolar interactions.O nt he contrary,C Oc an be slowly generated in situ by the decarbonylation of cyclopropenone in this study.T oo btain an on-alternating polyketone,t he copolymerization of 1.0 MPa ethylene with 1.0 mmol 1a at 120 8 8Cw as carried out using C.T he reaction led to the formation of acopolymer with units b as the dominant polar structures (Figure 1e;i.r. 1.80 %, nine ketone groups per 1000 CH 2 units, Mn4 100).…”

Section: Angewandte Chemiementioning

confidence: 99%

Synthesis of Polyethylene with In‐Chain α,β‐Unsaturated Ketone and Isolated Ketone Units: Pd‐Catalyzed Ring‐Opening Copolymerization of Cyclopropenone with Ethylene

2019

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Although various functionalizedu nits can be incorporated into polyolefins by transition metal catalyzed coordination copolymerizations of nonfunctionalized olefins with polar functional monomers,t he incorporated functional units are largely limited to aC1unit from either CO or C2 units from vinyl monomers.R eported here is the Pd-catalyzed copolymerization of ethylene with cyclopropenone,leading to incorporation of C3 units with functional groups, a,b-unsaturated ketones,i nt he chain. Coordination-insertion of the carbonyl group and ring opening of the strained threemembered ring are proposed as the key steps in the mechanism. Under different reaction conditions an isolated ketone structure was afforded as the major carbonyl unit, and could be generated by the copolymerization of ethylene with CO formed in situ from cyclopropenone.

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Section: Angewandte Chemiementioning

confidence: 99%

Synthesis of Polyethylene with In‐Chain α,β‐Unsaturated Ketone and Isolated Ketone Units: Pd‐Catalyzed Ring‐Opening Copolymerization of Cyclopropenone with Ethylene

2019

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“…Therefore, other catalytic approaches using special comonomers to incorporate isolated keto groups into PE were investigated more recently 17 . In free-radical growth, the low reactivity of the acyl radicals formed upon incorporation of CO hinders further chain growth and favors the formation of oligomers rather than PE materials 18 .…”

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confidence: 99%

Photodegradable branched polyethylenes from carbon monoxide copolymerization under benign conditions

et al. 2020

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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 13 C 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.

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“…For instance, no evidence for sequential trap of radicals by two molecules of CO was observed in Coffman's radical copolymerization of ethylene and CO even at extremely high CO pressures (>1000 atm, ethylene/CO = 3/7). 20,21 This study suggested that further trap of an acyl radical by CO occurs with great difficulty. 22,23 In the study of UV light/Pd-promoted atom transfer radical carbonylation of alkyl halides, Ryu reported that in some cases a mixture of singly and double carbonylated products, amides and α-ketoamides, could be obtained but with low selectivity (Fig.…”

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confidence: 91%

Switchable radical carbonylation by polarity-regulation

Lü

Xiao

et al. 2021

Preprint

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Carbonylation reactions involving CO as readily available C1 synthons have become one of the most important tools for construction of carbonyl compounds from feedstock chemicals in modern chemical synthesis. Whereas numerous catalytic methods for carbonylation reactions proceeding via ionic or radical pathways have been reported, an inherent limitation to these methods is the need to control switchable single and double carbonylative formation of value-added products from the same and simple starting materials. Here we describe a new strategy that exploits simple visible-light-driven photoredox catalysis to regulate the polarity of coupling partners to drive switchable radical carbonylation reactions. Controlled trap of various alkyl radicals by single or double CO thereby proceed smoothly with excellent selectivity in the presence of various amine nucleophiles at room temperature, generating valuable amides and α-ketoamides in a versatile and controlled fashion. Combined experimental and DFT computational studies suggest that trap of the initially formed acyl radical by the second molecule of CO to form α-ketoacyl radical is a facile but reversible process; and photoredox-catalyzed SET oxidation of natural nucleophilic amines into relatively electrophilic nitrogen radical cations is responsible for switchable coupling with such two radical intermediates.

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Compositional Relationships in the Copolymerization of Ethylene with Carbon Monoxide

Cited by 49 publications

References 0 publications

Synthesis of Polyethylene with In‐Chain α,β‐Unsaturated Ketone and Isolated Ketone Units: Pd‐Catalyzed Ring‐Opening Copolymerization of Cyclopropenone with Ethylene

Synthesis of Polyethylene with In‐Chain α,β‐Unsaturated Ketone and Isolated Ketone Units: Pd‐Catalyzed Ring‐Opening Copolymerization of Cyclopropenone with Ethylene

Photodegradable branched polyethylenes from carbon monoxide copolymerization under benign conditions

Switchable radical carbonylation by polarity-regulation

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