Oxidation-Reduction Properties General

The results are shown in Fig. 5. Generally, the monolayer catalysts have a certain activity either with or without the supply of oxygen. It thus reveals that only one atomic layer of ferric ions is needed for this reaction. However, the oxidation-reduction properties of the surface ferric ions strongly determine their activity. For instance, the MgO and ZnO-supported samples have a low activity due to the difficult reduction of ferric ions. The relatively superior performance of the... 

A primary goal of chemical separation processes in the nuclear industry is to recover actinide isotopes contained in mixtures of fission products. To separate the actinide cations, advantage can be taken of their general chemical properties [18]. The different oxidation states of the actinide ions lead to ions of charges from +1 (e.g., NpOj) to +4 (e.g., Pu" " ) (see Fig. 12.1), which allows the design of processes based on oxidation reduction reactions. In the Purex process, for example, uranium is separated from plutonium by reducing extractable Pu(IV) to nonextractable Pu(III). Under these conditions, U(VI) (as U02 ) and also U(IV) (as if present, remain in the... 

Practically in every general chemistry textbook, one can find a table presenting the Standard (Reduction) Potentials in aqueous solution at 25 °C, sometimes in two parts, indicating the reaction condition acidic solution and basic solution. In most cases, there is another table titled Standard Chemical Thermodynamic Properties (or Selected Thermodynamic Values). The former table is referred to in a chapter devoted to Electrochemistry (or Oxidation - Reduction Reactions), while a reference to the latter one can be found in a chapter dealing with Chemical Thermodynamics (or Chemical Equilibria). It is seldom indicated that the two types of tables contain redundant information since the standard potential values of a cell reaction ( n) can be calculated from the standard molar free (Gibbs) energy change (AG" for the same reaction with a simple relationship... 

General chemical properties of triazolopyridines, such as oxidations, reductions, reaction with electrophiles, reactions with nucleophiles, homolytic reactions, ring-opening reactions, and photochemical reactions can be found in <2002AHC(83)2>. 

Nonetheless, equilibrium considerations can greatly aid attempts to understand in a general way the redox patterns observed or anticipated in natural waters. In all circumstances equilibrium calculations provide boundary conditions toward which the systems must be proceeding, however slowly. Moreover, partial equilibria (those involving some but not all redox couples) are approximated frequently, even though total equilibrium is not approached. In some instances active poising of particular redox couples allows one to predict significant oxidation-reduction levels or to estimate properties and reactions from computed redox levels. 

In addition to chemical substrate concentration, chemical structure and physical/chemical properties have considerable impact on the rate and pathways of biodegradation. The chemical structure determines the possible pathways that a substrate may undergo, generally classified as oxidative, reductive, hydrolytic, or conjugative. 

Valence d electrons of transition metals impart special properties (e.g., color and substitution reactivity) to coordination complexes. These valence electrons can also be removed completely from (oxidation) or added to (reduction) metal d orbitals with relative facility. Such oxidation-reduction (redox) reactions, like substitution reactions, are integral to metal complex reactivity. Consider the role of redox chemistry in the synthesis of [Co(NH3)5C1]+, equation (1.8). In general, the preparation of cobalt(III) complexes (Chapters 2 and 5) starts with substitutionally labile cobalt(II) salts that are combined with appropriate ligands with subsequent oxidation of the metal by H202 or 02 to the substitutionally inert (robust) +3 state. 

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