Acid Catalyzed Disproportionation of Anthrahydroquinone to Anthraquinone and Anthrone

Wermeckes, Bernd; Beck, F.

doi:10.5796/electrochemistry.62.1202

Cited by 18 publications

(15 citation statements)

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“…Recently, the formation of an electrochemically inactive dimer of the oxidized AQDS molecules was observed by Wiberg et al [ 16 ] significantly reducing the electrolyte utilization. According to Wermeckes et al [ 17 ] the degradation of unsubstituted AQ in an acidic environment consists of disproportionation of its 2e – reduced form (anthrahydroquinone, AQDSH 2 ) to anthraquinone and electrochemically inactive anthrone. Anthrone formation, which is presumed to proceed also for substituted anthraquinone derivatives, has been observed in case of 2,6-dihydroxyanthraquinone (2,6-DHAQ) in an alkaline environment (pH 14) by Goulet et al [ 18 ] significantly contributing to the capacity fade of RFB using 2,6-DHAQ negolyte and ferrocyanide-based posilyte.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Mazúr

Mrlík

et al. 2021

Molecules

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Despite intense research in the field of aqueous organic redox flow batteries, low molecular stability of electroactive compounds limits further commercialization. Additionally, currently used methods typically cannot differentiate between individual capacity fade mechanisms, such as degradation of electroactive compound and its cross-over through the membrane. We present a more complex method for in situ evaluation of (electro)chemical stability of electrolytes using a flow electrolyser and a double half-cell including permeation measurements of electrolyte cross-over through a membrane by a UV–VIS spectrometer. The method is employed to study (electro)chemical stability of acidic negolyte based on an anthraquinone sulfonation mixture containing mainly 2,6- and 2,7-anthraquinone disulfonic acid isomers, which can be directly used as an RFB negolyte. The effect of electrolyte state of charge (SoC), current load and operating temperature on electrolyte stability is tested. The results show enhanced capacity decay for fully charged electrolyte (0.9 and 2.45% per day at 20 °C and 40 °C, respectively) while very good stability is observed at 50% SoC and lower, even at 40 °C and under current load (0.02% per day). HPLC analysis conformed deep degradation of AQ derivatives connected with the loss of aromaticity. The developed method can be adopted for stability evaluation of electrolytes of various organic and inorganic RFB chemistries.

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Section: Introductionmentioning

confidence: 99%

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Mazúr

Mrlík

et al. 2021

Molecules

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“…37 Indeed, at higher concentrations still, it is likely that anthraquinones decompose in a bimolecular fashion. 38 Nonetheless, the ratio of peak integrations, q c /q a , is 1.00, pointing to the chemical reversibility of this two-electron, two-proton process. In line with literature reports, 36 preparative electrolysis at 0.0 V versus RHE leads to clean conversion of the quinone to AQDSH 2 2À as judged by UV visible (UV-vis) spectroscopy ( Figure S1).…”

Section: Electrochemistry Of the Electron-proton Transfer Mediatormentioning

confidence: 96%

Electrosynthesis of Hydrogen Peroxide by Phase-Transfer Catalysis

Murray

Voskian

Schreier

et al. 2019

Joule

113

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The portable electrochemical generation of hydrogen peroxide (H 2 O 2) from air and water would enable greater utilization of this versatile green oxidant in applications ranging from environmental remediation to portable sanitation. Currently, electrochemical H 2 O 2 synthesis is hampered by the lack of lowcost, non-toxic catalysts that selectively reduce O 2 to H 2 O 2 and the lack of low-energy methods for separating the produced H 2 O 2 from the electrolyte media. Herein, we show that a disulfonated anthraquinone can simultaneously catalyze the selective conversion of O 2 to H 2 O 2 and shuttle between immiscible aqueous and organic phases via ion exchange. We exploit both of these properties in a flow system to assemble an all-Earth-abundant prototype device for the continuous generation and separation of H 2 O 2 into an electrolyte-free water stream. The combination of molecular redox mediation and phase-transfer catalysis demonstrated here has broad implications for the electrochemical synthesis and isolation of value-added chemicals and fuels.

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“…There is an early preparative observation on the rapid formation of anthraquinone (AQ) 3 and anthrone (Ant) 4 from anthrahydroquinone (AQH2) 1 in cold concentrated sulfuric acid [83] according the overall reaction 2 AQH2 -AQ + Ant + H20 (40) A kinetic evaluation in 85% &SO4 [84] led to a mechanism according to Fig. The rate constants for this second-order reaction are, for 1, 5, and 1 5~ H2S04, 0.9 x and 30 x 10-3Vmolh, respectively [33,80,85]. Oxanthrol2 is a tautomeric intermediate.…”

Section: Reversible Electroorganic Reactionsmentioning

confidence: 99%

Acid Catalyzed Disproportionation of Anthrahydroquinone to Anthraquinone and Anthrone

Cited by 18 publications

References 0 publications

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Evaluation of Electrochemical Stability of Sulfonated Anthraquinone-Based Acidic Electrolyte for Redox Flow Battery Application

Electrosynthesis of Hydrogen Peroxide by Phase-Transfer Catalysis

Graphite, Carbonaceous Materials and Organic Solids as Active Electrodes in Metal‐Free Batteries

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