33624-86-1Relevant articles and documents
Electrochemical Study of the Heterogeneously Catalysed Reaction between N,N-Dimethyl-p-phenylenediamine and Co(III)(NH3)5Cl(2+) at Monometallic and Bimetallic Surfaces of Silver and Gold
Chen, Yao-Hong,Nickel, Ulrich,Spiro, Michael
, p. 617 - 624 (1994)
The mechanism of the heterogeneously catalysed reaction between N,N-dimethyl-p-phenylenediamine and Co(III)(NH3)5Cl(2+) at silver, gold and silver-on-gold (Ag/Au) discs has been studied by means of electrochemical methods.Both the mixed (or mixture) potentials and the mixture currents were determined by recording the current-potential curves of the reactants.Silver halide, formed during the reaction, was determined by subsequent galvanostatic reduction.The reaction at silver was strongly inhibited by the formation of silver halide whereas the reaction at gold was inhibited by adsorption of the organic compounds as well as by iodide.At Ag/Au discs almost no inhibition occurred.The explanation is that the reduction of the cobalt complex takes place predominantly at the silver surface whereas the simultaneous oxidation of the p-phenylenediamine occurs on the gold.In this way the formation of inhibiting silver halide is suppressed as well as the inhibition caused by the adsorption of p-phenylenediamine.
Mechanism and Kinetics of the Photocatalyzed Oxidation of p-Phenylenediamines by Peroxydisulfate in the Presence of Tri-2,2'-bipyridylylruthenium(II)
Nickel, Ulrich,Chen, Yao-Hong,Schneider, Siegfried,Silva, Maria I.,Burrows, Hugh D.,Formosinho, Sebastiao J.
, p. 2883 - 2888 (2007/10/02)
The autocatalytic oxidation of p-phenylenediamines with peroxydisulfate can be strongly enhanced by irradiation in the presence of tri-2.2'-bipyridylylruthenium(II).Ru(bpy)32+ acts as photosensitizer and photocatalyst.First, Ru(bpy)33+ is formed by quenching excited Ru*(bpy)32+ with S2O82-.Then the ruthenium(III) complex oxidizes p-phenylenediamine.The resulting Ru(bpy)32+ can start the cycle again.The photocatalytic oxidation of N,N-diethyl-p-phenylenediamine as well as the dark reactions were studied with stopped-flow techniques.The mechanism of this complex reaction is discussed in detail.
Mechanismus der quasi-homogenen Oxidation von p-Phenylendiaminen mit Silbernitrat
Nickel, U.,Ruehl, N.,Zhou, B. M.
, p. 33 - 52 (2007/10/02)
The redox reaction between p-phenylenediamines and silver nitrate in aqueous acid solution was observed optically in a double wavelength photometer.In presence of a nobel metal plate or larger clusters of silver, production of p-semiquinonediimines respective silver starts immediately, whereas without clusters present at the beginning of the reaction the maximum reaction rate is attained only after a certain induction period.The length of this induction period depends on the pH and the concentration of p-phenylenediamine, but not on the silver ion concentration.It is not the number of the clusters that influences the induction period, but their size.The rate of the main reaction, however, is proportional to the number of the clusters formed.In dilute solutions the main reaction is of first order concerning both of the two reactants, in concentrated solution, however, it is of smaller order. - Keywords: Oxidation / Cluster / p-Phenylenediamines / Silver / Photographic development
