Mechanism of voltammetric determination of pKa of Brønsted–Lowry acids in aprotic solvent by quinone reduction

Connecting Thermodynamics and Kinetics of Proton Coupled Electron Transfer at Polyoxovanadate Surfaces Using the Marcus Cross Relation

“…Conversely, a loss of reversibility is observed in the second reduction event, suggesting that the increased basicity of the two-electron reduced cluster is sufficient to deprotonate the organic acid. This electrochemical behavior is reminiscent to that of quinone/hydroquinone systems measured in organic solvent; 41,42 upon introduction of organic acids, a loss of reversibility is observed at the most reducing event as a result of the interaction of the acidic proton with the two-electron reduced form of the quinone.…”

Kinetic and mechanistic investigations of dioxygen reduction by a molecular Cu(ii) catalyst bearing a pentadentate amidate ligand

“…As reported previously, parent- or substituted benzoquinones (BQs) undergo two consecutive reduction processes in organic solvents generating BQ˙ − and BQ 2− , respectively. 67,68 When Brønsted acids are added to the BQ solution during CV, a new cathodic peak appears at a more anodic region than the first reduction event of BQ. 67,68 This prepeak was attributed to the protonation of the quinone, resulting in a two-proton and two-electron reduction to form a hydroquinone from BQ.…”

“…67,68 When Brønsted acids are added to the BQ solution during CV, a new cathodic peak appears at a more anodic region than the first reduction event of BQ. 67,68 This prepeak was attributed to the protonation of the quinone, resulting in a two-proton and two-electron reduction to form a hydroquinone from BQ. Kim et al suggested that the redox properties of BQ involving the ECE (e − H + e − ) process can be influenced by the strength of the Brønsted acid used.…”

Two Different Strategies Based on Three‐Way Analysis Models of UV Spectroscopic and Spectrochromatographic Measurements to Quantify the Acidity Constant of Acetylsalicylic Acid

“…That is why there is a growing interest in developing feasible, accurate and alternative methods for determination of pKa values. [1][2] A wide range of experimental techniques, such as potentiometry, [3][4][5] spectrophotometry, [3,[6][7] voltammetry, [8][9] high performance-liquid chromatography (HPLC), [10] capillary electrophoresis (CE) [3,[11][12] are used for pKa determination. The use of all these techniques are based on the measurement of an analytical response as a function of medium pH for determining acid-base dissociation constant of the analyte.…”