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The electrochemical initiated heterocoupling of 3-methylcatechol and n-hexylamine was investigated. The oxidation of 3-methylcatechol was performed in an electrochemical flow cell with glassy carbon as the working electrode. As a result, the two-electron, two-proton oxidised chinone intermediate undergoes a C-N coupling reaction in the presence of an amine (Michael addition). This mono coupling product can undergo a second two-electron, two-proton oxidation depending on acidic or basic conditions and substrate ratios. This flow cell was coupled on-line with electrospray ionisation mass spectrometry to identify the possible coupling products. Higher substrate concentrations were performed off-line as first scale-up experiments in a two-step procedure. [ABSTRACT FROM AUTHOR]

Flavonols, a class of flavonoids, are jointly responsible for antioxidant activities as free radical acceptors in flowers, fruits and vegetables. Due to their electroactive behaviour, the oxidation of chrysin, flavonol, kaempferol, morin, quercetin and myricetin in methanol was performed in an electrochemical flow cell with glassy carbon as the working electrode. This flow cell was coupled online with electrospray ionisation mass spectrometry to identify the possible oxidation products. Based on these experiments, it was concluded that when certain structural requirement are present, the initial electrode reaction of flavonols involves an electron delivery electrochemical step followed by a chemical step via methanol addition. The redox activity of the selected species explains the number of observed multiple methoxylation. Moreover, we identified a second two-electron, two-proton oxidation of the formed oxidation products of quercetin and myricetin for the first time. [ABSTRACT FROM AUTHOR]

A fundamental electrochemical study of several highly diluted ionic liquids (ILs) at the interface between two immiscible electrolyte solutions (ITIES) is reported to evaluate the electrochemical and the solvation properties of [BMIM]Cl, [BMIM]BF 4 , [BMIM]OTf, [EMIM]Br and [AMIM]Cl. The interface is formed between a hydrophilic electrolyte dissolved in water and a hydrophobic electrolyte dissolved in an organic solvent, here 1,2-dichloroethane (DCE). The transfer of the highly diluted ionic species from the water phase into the organic phase occurs when an electrical potential difference is applied across the interface. Standard Gibbs energy of transfer, the relative hydrophilicity/hydrophobicity and transfer coefficients across the interface of the selected ILs are determined by cyclic voltammetry at large ITIES. [ABSTRACT FROM AUTHOR]