Kolbe Reactions

Schäfer, Hans J.

doi:10.1016/b978-0-08-052349-1.00075-5

Cited by 17 publications

(9 citation statements)

References 174 publications

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“…At diluted glycine concentration, the experimental anodic oxidation leads to a monoelectronic oxidative decarboxylation in agreement with the literature, as depicted in reaction : ,− …”

Section: Resultssupporting

confidence: 88%

From Anodic Oxidation of Aliphatic α-Amino Acids to Polypeptides by Quantum Electrochemistry Approach: Beyond Miller–Urey Experiments

2019

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For years, polypeptide formation has fascinated the scientific world because its understanding could lead to one of the possible explanations for the origin of life. Anodic oxidation of aliphatic α-amino acids in aqueous electrolytes can result either in their decomposition or in their polymerization into polypeptide. This behavior depends experimentally on both amino acid concentration and pH. The elucidation of the involved mechanisms remains a challenge because of the multitude of products which can be obtained. In this context, the electrochemical behavior of glycine and alanine on a biased platinum surface was examined at the nanoscale by quantum electrochemistry via the effective screening medium method. Several electrochemical systems with different concentrations and pH values have been explored. Simulations of the anodic oxidation of the amino acids have not only confirmed their electropolymerization and decomposition at high and low concentrations, respectively, but also have revealed unsuspected mechanisms at the origin of polypeptide formation. This sheds new light on electrochemistry of α-amino acids, on occurrence of polypeptides, and more generally on organic electrochemistry.

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“…At diluted glycine concentration, the experimental anodic oxidation leads to a monoelectronic oxidative decarboxylation in agreement with the literature, as depicted in reaction : ,− …”

Section: Resultssupporting

confidence: 88%

From Anodic Oxidation of Aliphatic α-Amino Acids to Polypeptides by Quantum Electrochemistry Approach: Beyond Miller–Urey Experiments

2019

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“…These are based on the concept of adsorption of deprotonated carboxylic acid (carboxylate) on the surface, thereby inhibiting the competing oxygen evolution. [16][17][18][19][20][21] The formation of this layer of adsorbate, also referred to as the inflection zone, is observed as a flat region in a broad potential range above 2.1 V vs. RHE (reversible hydrogen electrode). Recently Liu et al [22] revealed that the inflection zone arises from a shift in the rate determining step of oxygen evolution.…”

Section: Introductionmentioning

confidence: 99%

Study on the Effect of Electrolyte pH during Kolbe Electrolysis of Acetic Acid on Pt Anodes

et al. 2022

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Kolbe already discovered in 1849 that electrochemical oxidative decarboxylation of carboxylic acids is feasible and leads to formation of alkanes and CO 2 , via alkyl radical intermediates. We now show for Pt electrodes that Kolbe electrolysis of acetic acid is favored in electrolytes with a pH similar to, or larger than the pKa of acetic acid, suppressing the formation of O 2 . However extended duration of electrolysis of acetate at basic pH results in loss of Faradaic efficiency to ethane, compensated by the formation of methanol. This change in selectivity is likely caused by the dissolution of CO 2 near the electrode-electrolyte interface, resulting in enlarged concentration of bicarbonate/ carbonate. On the positively polarized, and oxidized Pt surface, these anions seem to inhibit homocoupling of methyl radicals to ethane. These results demonstrate that reaction selectivity in acetic acid (acetate) oxidation using oxidized Pt electrodes is determined by the pH and the anionic composition of the electrolyte.

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“…53−55 For example, acetic acid can generate the coupling product ethane with a high yield of 93%; however, if the hydrogen atom of the acetic acid's α-position is substituted by any other alkyl groups, the coupling product yield will decrease. 53 In addition, the concentration of acetic acid may also have an influence on the overpotential. In the case of a pure acetic acid solvent environment, Pt can also be used as an anode for the acetic acid oxidation.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

First-Principles Investigation of the Unique Role of Anode Surfaces in Organic Electrochemical Reactions

Zhang,

Wen,

Chen

et al. 2023

J. Phys. Chem. C

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The Kolbe reaction is one of the most classical electrochemical reactions, which enables carboxylic acids or carboxylates to undergo decarboxylation processes via anodic oxidation, forming dimeric alkanes. The reaction could be influenced by many factors separately or synergistically, and changing a single factor may completely change the reaction path. Platinum (Pt) and graphite are common electrode materials used in electrochemical reactions. Electrochemists have obtained abundant empirical evidence that the electrode materials surfaces can affect reaction paths and products, but conventional experiments have difficulty obtaining a microscopic understanding of the specific role of surfaces. In this work, we employ ab initio atomic models to simulate the Kolbe-type oxidation reactions of acetic acid as a model reactant on Pt and graphite surfaces from both thermodynamic and kinetic perspectives. An atomic-scale understanding is presented to explain why Pt and graphite electrode surfaces exhibit different preferences for reaction paths, and we also reveal the joint impact of surface morphologies and adsorption configurations on the kinetics of rate-limiting steps. For the surface morphologies, low-coordinated Pt atoms make the decarboxylation easier to happen on the Pt surface than on the graphite surface. The adsorption configuration of oxidative reaction intermediates is also a determining factor for the energy barriers of different reaction paths on the two surfaces. These discoveries provide mechanistic insights into the anodic oxidation of carboxylic acids, facilitating the understanding of microscopic electrochemical processes and the exploration of new electrochemistry.

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Kolbe Reactions

Cited by 17 publications

References 174 publications

From Anodic Oxidation of Aliphatic α-Amino Acids to Polypeptides by Quantum Electrochemistry Approach: Beyond Miller–Urey Experiments

From Anodic Oxidation of Aliphatic α-Amino Acids to Polypeptides by Quantum Electrochemistry Approach: Beyond Miller–Urey Experiments

Study on the Effect of Electrolyte pH during Kolbe Electrolysis of Acetic Acid on Pt Anodes

First-Principles Investigation of the Unique Role of Anode Surfaces in Organic Electrochemical Reactions

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