Anode-Initiated Polymerizations of Olefins and Tetrahydrofuran

Nakahama, Seiichi; Hashimoto, Kazuhito; Yamazaki, Noboru

doi:10.1295/polymj.4.437

Cited by 15 publications

(5 citation statements)

References 8 publications

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“…A coulometric measurement carried out at an applied potential of E w = −3.0 V (THF; [ n Bu 4 N][PF 6 ]) gave an electron count of approximately 1.5 e – per molecule 4 . Coulometry on main-group compounds is notoriously problematic and tends to give a low electron count due to the inherent instability of radical species, reactions between the electrode products and still untransformed analyte molecules, or adsorption of the electrogenerated species to the electrode surface. , In the present case, the problem is aggravated by THF polymerization at the anode . Given this background, our bulk electrolysis indicates that, in fact, two electrons could be delivered at the same potential value.…”

Section: Results and Discussionmentioning

confidence: 75%

“…41,45 In the present case, the problem is aggravated by THF polymerization at the anode. 46 Given this background, our bulk electrolysis indicates that, in fact, two electrons could be delivered at the same potential value. For a two-electron reduction, the occurrence of only one irreversible reduction wave in the cyclic voltammogram again points toward a structural reorganization associated with one or both electrontransfer steps that leads to similar or inverted energetic potentials.…”

Section: ■ Results and Discussionmentioning

confidence: 91%

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Forming B–B Bonds by the Controlled Reduction of a Tetraaryl-diborane(6)

et al. 2016

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Dimeric aryl(hydro)boranes can provide suitable platforms for the synthesis of boron-containing graphene flakes through reductive B-B coupling. Two-electron reduction of 1,2:1,2-bis(4,4'-di-tert-butyl-2,2'-biphenylylene)diborane(6) (4) with LiNaph/THF establishes a B-B σ bond but can be accompanied by substituent redistribution. In the singly rearranged product, Li2[6], only one 1,2-phenyl shift has occurred. The doubly ring-contracted product, Li2[7], consists of two 9H-9-borafluorenyl moieties that are linked via their boron atoms. When the amount of LiNaph/THF is increased to 4 equiv, Li2[6] is subsequently observed as the dominant species. Addition of 11 equiv of LiNaph/THF results in over-reduction with hydride elimination to afford the doubly boron-doped dibenzo[g,p]chrysene Li2[1]. In contrast, excess KC8 reduces 4 to the corresponding dihydro-dibenzo[g,p]chrysene, K2[5], with a trans-HB-BH core. Hydride abstraction from K2[5] with 1 equiv of 4 leads to K[8], in which the central B-B bond is bridged by a single hydrogen atom. K[8] is also obtained upon treatment of 4 with 1 equiv of KC8. All products have been characterized by multinuclear NMR spectroscopy and X-ray crystallography.

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Section: Results and Discussionmentioning

confidence: 75%

Section: ■ Results and Discussionmentioning

confidence: 91%

Forming B–B Bonds by the Controlled Reduction of a Tetraaryl-diborane(6)

et al. 2016

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“…There are three orders of magnitude more solvent molecules than the number of electrons passed, so it is unlikely that the visible changes are solely caused by electrochemical reactions. The anodic reaction in a THF‐based electrolyte has previously been described with a simple electrochemical step that leads to a cationic ring‐opening polymerization of THF, [36,37] as shown in Equations (4), (5) and (6). In addition, this polymerization could in principle also be initiated by protonation of the oxygen in THF [38] …”

Section: Resultsmentioning

confidence: 99%

Is Ethanol Essential for the Lithium‐Mediated Nitrogen Reduction Reaction?

Bjarke Valbæk Mygind,

Pedersen,

et al. 2023

ChemSusChem

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The lithium‐mediated nitrogen reduction reaction (Li‐NRR) is a promising method for decentralized ammonia synthesis using renewable energy. An organic electrolyte is utilized to combat the competing hydrogen evolution reaction, and lithium is plated to activate the inert N2 molecule. Ethanol is commonly used as a proton shuttle to provide hydrogen to the activated nitrogen. In this study, we investigate the role of ethanol as a proton shuttle in an electrolyte containing tetrahydrofuran and 0.2 M lithium perchlorate. Particularly designed electrochemical experiments show that ethanol is necessary for a good solid‐electrolyte interphase but not for the synthesis of ammonia. In addition, electrochemical quartz crystal microbalance (EQCM) demonstrates that the SEI formation at the onset of lithium plating is of specific importance. Chemical batch synthesis of ammonia combined with real‐time mass spectrometry confirms that protons can be shuttled from the anode to the cathode by other species even without ethanol. Moreover, it raises questions regarding the electrochemical nature of Li‐NRR. Finally, we discuss electrolyte stability and electrochemical electrode potentials, highlighting the role of ethanol on electrolyte degradation.

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“…There are three orders of magnitude more solvent molecules than the number of electrons passed, so it is unlikely that the visible changes are solely caused by electrochemical reactions. The anodic reaction in a THF-based electrolyte has previously been described with a simple electrochemical step that leads to a cationic ring-opening polymerization of THF, [36,37] as shown in Equations ( 4), ( 5) and ( 6). In addition, this polymerization could in principle also be initiated by protonation of the oxygen in THF.…”

Section: Ethanol-mediated Changes In Electrolyte Transformations and ...mentioning

confidence: 99%

Is Ethanol Essential for the Lithium-Mediated Nitrogen Reduction Reaction?

Mygind,

Bruun Pedersen,

Vesborg

et al. 2023

Meet. Abstr.

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Ammonia is used extensively as a fertilizer in agriculture and in the chemical industry. It also has the potential to store carbon-neutral fuel (hydrogen) in the future. To help meet the future demand for ammonia, the electrochemical nitrogen reduction reaction (NRR) has received much attention. It would serve as a decentralized method of synthesizing ammonia at low temperature and pressure. [1] To this day, the most promising NRR results have been shown via the lithium-mediated approach, in which lithium metal is electroplated in an organic electrolyte containing a lithium salt, saturated nitrogen gas, and a proton shuttle. The saturated nitrogen in the electrolyte reacts with electrodeposited lithium and protons are subsequently delivered by the shuttle. The local availabilities of protons and nitrogen are crucial for achieving a high selectivity towards ammonia rather than hydrogen evolution. The selectivity is heavily affected by the solid electrolyte interphase (SEI) which is formed between the electrodeposited lithium and bulk electrolyte. [2,3,4,5] This study investigates the role of ethanol as the proton shuttle in the lithium-mediated nitrogen reduction reaction (Li-NRR). In situ mass spectrometry and electrochemical quartz crystal microbalance are used to elucidate the importance of ethanol. Furthermore, particularly designed chronopotentiometry experiments are designed to provide additional information, allowing for a detailed discussion of ethanol’s multifaceted role in the Li-NRR. It is shown that ethanol is crucial for the formation of the SEI, but not necessary for the actual synthesis of ammonia. The SEI formation in the Li-NRR system is critically influenced by ethanol at the onset of lithium plating. Ethanol is not necessary to shuttle protons from the anode to the cathode. Furthermore, it is shown that lithium is an active species in the Li-NRR system even without electrochemistry. Finally, it is revealed that ethanol plays an important role in the context of anodic electrode potentials and electrolyte stability. References MacFarlane, D. R. et al. Adv. Mater. 32, 1904804 (2020) Du, H-L et al. Nature 609, 722 (2022) Lazaouski, N. et al. ACS Catal. 12, 5197-5208 (2022) Andersen, S. Z. et al. Energy Environ. Sci. 13, 4291-4300 (2020) Andersen, S. Z. et al. Nature 570, 504 (2019)

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Anode-Initiated Polymerizations of Olefins and Tetrahydrofuran

Cited by 15 publications

References 8 publications

Forming B–B Bonds by the Controlled Reduction of a Tetraaryl-diborane(6)

Forming B–B Bonds by the Controlled Reduction of a Tetraaryl-diborane(6)

Is Ethanol Essential for the Lithium‐Mediated Nitrogen Reduction Reaction?

Is Ethanol Essential for the Lithium-Mediated Nitrogen Reduction Reaction?

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