Aromatic compounds electrooxidation

Similar studies were carried out with benzoic acid on porous palladium electrodes [150]. The objective of this work was to investigate the adsorption processes and the reactivity of benzoic acid on different noble metals, in order to compare these results with those obtained for related aromatic compounds. On-line mass spectroscopy analysis of volatile products revealed that the adsorption of benzoic acid is irreversible at platinum while it is mainly reversible on palladium. Accordingly, different catalytic activity of platinum and palladium was found in the electrooxidation. 

A. Olefinic compounds Acetylenic compounds Aromatic compounds Carbonyl compounds F/c-Oxygen compounds Nitrogen compounds Sulfur compounds Halogen compounds Other heteroatom compounds Organometallic compounds Stereoselective and Stereospecific Electrooxidation A. Carboxylic acids Acetoxylation Methoxylation Acetamidation... 

Instrumentation. A cell design employing reticulated vitreous carbon as the working electrode material that enables both UV-Vis absorption and luminescence measurements has been described [47]. A thin-layer cell with a platinum working electrode has been developed [69]. The luminescence of the electrooxidation products of o-tolidine as a function of electrode potential was studied. A simplified flow cell design has been reported [70]. Luminescence spectra and fluorescence intensity for various aromatic compounds and their electrochemical and photochemical reaction products were observed as a function of flow rate, current and time after the potential step. In the latter study the electrooxidation of p-phenylenediamine (PPD) was examined. The cyclic voltammogram showed two oxidation peaks the first one is assumed to be caused by the formation of the radical cation according to... 

Sekiguchi, K., Atobe, M., and Fuchigami, T. (2003). Electrooxidative polymerization of aromatic compounds in l-ethyl-3-methylimidazolium trifluoromethanesulfonate room-temperature ionic liquid./. Electroanal. Chem., 557, pp. 1-7. 

Electrooxidation of aromatic compounds has been intensively investigated, and many useful fine chemicals have been prepared by both side-chain and aromatic nucleus oxidation. Side-chain oxidation of alkylbenzenes may furnish benzyl alcohols, benzyl acetates, benzyl methyl ethers, Af-benzyl acetamides, benzaldehydes, benzoic acids, and so on. For instance, electrooxidation of p-methoxytoluene affords p-methoxybenzyl methyl ether, p-methoxybenzaldehyde, and/or its dimethylacetal depending on the choice of electrolysis media [3]. Many examples of electrooxidation of aromatic nucleus have been also reported. p-Quinones and their methyl acetals and semiquinones are prepared by electrooxidation of phenol derivatives and hydroquinones [3]. Nucleus-nucleus coupling of methoxybenzene derivatives... 

Co(III)/Co(I) redox-mediated electroreduction [18]. Oxidative transformations, e.g., oxidation of side chain of aromatic compounds, 1,2-dihydroxylation of olefins, and oxidation of alcohols and amines, are attained by electrooxidation with CAN, Ct203, Mn(S04)2, TiC104, OSO4, RUO2, and so on as a mediator [19]. 

Fleischmann et al s 34 report cyclic voltammetry data for the oxidation of a series of aromatic hydrocarbons in a molten salt electrolyte, AlCl3-NaCl-KCl at 150°. Electrooxidation in this medium occurs at unusually low oxidation potentials. Tris-(p-substituted phenyl)amines, with the exception of tri (p-nitrophenyl) amine, yield very stable radical cations by all electrochemical criteria 380>S42 Mono- and bis-p-substituted triphenylamines, however, dimerize with rate constants ranging from 101 to 10s M 1 sec 1 to benzidines 176 (Eq. (237)), which subsequently are oxidized to the radical cations 177, whose ESR-spectra are observed. Dimerization is fastest with the p-N02 andp-CN-derivative, in accordance with HMO calculations, which predict the highest spin sensity in the p-position of these compounds 542 ... 

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