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Chromate pigmented paints are commonly used in painting the aluminium parts of the aircrafts. This study is directed to find an alternative inhibitor in place of chromate the most widely used inhibitor in aircraft paints. In that effect sodium benzoate, polyacrylic acid (PAA), strontium chloride, cerium chloride, malic acid, glycin, cobalt sulphate, pyrrol, and quartamin T (alkyl three methyl ammonium chloride) were tried in place of Na2CrO4. The anodic and cathodic polarisation curves were recorded and weight loss measurements were carried out in 0.1 M NaCl solutions with and without inhibitor. Quartamin T, pyrrol and PAA which were observed to provide satisfactory inhibition effect were added to the polyurethane based paints used in the aircraft industry and the Al (2024) alloy painted with this paint was subjected to electrochemical corrosion tests in 0.1 M NaCl. Pyrrol and quartamin T containing paints were observed to give results as good as those obtained with chromate containing paints. Inhibitoren fur den Schutz von Aluminiumlegierungen in der Luft- und Raumfahrt Chromatpigmentierte Farben werden ublicherweise fur die Beschichtung der Aluminiumteile von Flugzeugen eingesetzt. Die vorliegende Untersuchung beschaftigt sich damit, einen alternativen Inhibitor zum Ersatz von Chromat, dem fur Flugzeugbeschichtungen am meisten verwendeten Inhibitor, zu finden. Zu diesem Zweck wurden Natriumbenzoat, Polyacrylsaure (PAA), Strontiumchlorid, Ceriumchlorid, Apfelsaure, Glycine, Kobaltsulfat, Pyrrol und Quartamin T als alternative fur Na2CrO4 getestet. In 0,1 M NaCl Losungen mit und ohne Inhibitor wurden anodische und kathodische Polarisationskurven aufgenommen sowie Massenverlustmessungen durchgefuhrt. Die Substanzen, die offensichtlich einen zufriedenstellenden Inhibierungseffekt liefern (Quartamin T, Pyrrol und PAA), wurden den in der Luftfahrtindustrie verwendeten, auf Polyurethan basierenden Farben zugesetzt, und die mit dieser Farbe beschichtete Al (2024) Legierung wurde elektrochemischen Korrosionsversuchen in 0,1 M NaCl unterzogen. Pyrrol und Quartamin T enthaltene Farben verhielten sich ahnlich gut wie die Farben mit Chromat.

WOS: 000176692700006 The electrochemical reduction of four 4'-halogene-4-aminoazobenzene derivatives was studied in water/ethyl alcohol mixtures at various pH values using cyclic voltammetry (CV), sampled d.c. polarography (SCP), differential pulse polarography (DPP), chronoamperometry (CA) and constant potential coulometry (BE). The diffusion coefficients and the number of electrons transferred were determined using chronoamperometric Cottrell slope and ultramicroelectrode (UME) steady-state current. The transfer coefficient, heterogeneous rate constant and free energy of reduction of azobenzene derivatives were determined by Koutecky approach. Transfers of four-electron in acidic and two-electrons in basic media were established. Under the conditions employed, the reduction reaction was diffusion-controlled Also the substituent effect of halogens was examined.

This paper describes an investigation of the reduction of nitrobenzene to p-aminophenol by the use of CV, RDE and preparative electrolysis with Cu and Cu(Hg) electrodes. The preparative electrolyses of nitrobenzene were carried out at controlled current and controlled potential conditions using copper and amalgamated copper using a new semipilot (laboratory) scale system in the absence of an organic cosolvent. The effects of redox reagents and the concentration of nitrobenzene in catholyte added to the medium were also examined. The best results were obtained with 2.3% BiCl3 at nitrobenzene concentration of 0.144 g cm(-)3 catholyte. The most suitable electrode material was found to be amalgamated copper and the reduction of nitrobenzene to p-aminophenol was found to follow an ECE mechanism.

WOS: 000176397800007 In this study, the electrochemical behaviour of 4'-halogene-N,N-dimethyl-4-aminoazobenzene derivatives were investigated using various polarographic and voltammetric methods. The peak potentials of these derivatives were observed to shift towards negative values with increase in pH. The standard rate constants were determined with (Laviron technique) or without (Nicholson and Klingler-Kochi techniques) taking the adsorption phenomena into account. The diffusion coefficients were calculated from the cyclic voltammetric data using the method developed by Garrido. The amount of adsorbed substances (surface excess values) and transfer coefficients for the electron transfer were also determined. These compounds can be quantitatively determined between 1 x 10(-5) M to 2 x 10(-7) M with DPP.

This study is concerned with the cathodic reduction of 4-nitroso-N,N-dimethylaniline to 4-amino-N,N-dimethylaniline in 1.0 M HCl and 1.0 M H2SO4 containing 10% MeOH. The effect of cathode material, supporting electrolyte, electroactive compound concentration, temperature and current density in the electrochemical synthesis of 4-amino-N,N-dimethylaniline were investigated. The best cathode material was tin, which gave a selectivity of 92.7% with a current yield of 90.3% at a current density of 6 mA cm(-2). The final electrolysis product was obtained as its respective HCl and H2SO4 salts and their structures were elucidated using spectrochemical techniques.

The purpose of this study was to investigate the anodic oxidation of glucose on Ptz/Pt electrode in acidic and alkaline media by comaring the voltammograms of glucose and its possible oxidation products such as gluconic, glucuronic, glucaric, glyoxylic, glycolic and tartaric acids. Glucose was also subjected to constant potential electrolysis at its peak potentials and the resulting voltammograms were compared with those of above mentioned acids. Based upon these and the literature data oxidation mechanism for glucose in both acidic and alkaline media were proposed. The mechanism was also confirmed by the TLC study of the solution subjected to prolonged electrolysis at the oxidation potential of glucose.