Acidity-controlled redox reactions

Gelation Reactions by Acidity-Controlled Redox Reactions... 

Acid fracturing, friction reducers, 15 Acid hydrolysis, lignin, 173 Acid injection into carbonate reservoir, 610-611 Acid-rock reactions, rate, 15,16 Add wormholing in carbonate reservoirs, 608-620 in carbonate rocks, 610-611 Acidity-controlled redox reactions, 141-142 Addization... 

Buchanan and co-workers studied the behavior of various aromatic compounds in antimony(III) molten salts [30]. These salts can act both as mild Lewis acids and allow redox reactions to take place. The Lewis acidity of the melt can be tuned by controlling the concentration of [SbCl2]. Basic melts are formed by addition of a few mol % of a chloride donor such as KCl, whereas acidic melts are formed by addition of chloride acceptors such as AICI3 (Scheme 5.1-11). 

Some of the critical enzymes in our cells are metalloproteins, large organic molecules made up of folded polymerized chains of amino acids that also include at least one metal atom. These metalloproteins are intensely studied by biochemists, because they control life and protect against disease. They have also been used to trace evolutionary paths. The d-block metals catalyze redox reactions, form components of membrane, muscle, skin, and bone, catalyze acid-base reactions, control the flow of energy and oxygen, and carry out nitrogen fixation. 

The approach is based on proper control of the acidity of the redox reaction mentioned earlier. A general equation of the dichromate-disulfite reaction as+a function of acidity is expressed in Equation 8 where Cr(0H)g and H are the hypothetical products. 

Control of Solution Acidity. Many inorganic and organic redox reactions involve hydronium ions, for example... 

There has been a resurgence of interest in proton-coupled redox reactions because of their importance in catalysis, molecular electronics and biological systems. For example, thin films of materials that undergo coupled electron and proton transfer reactions are attractive model systems for developing catalysts that function by hydrogen atom and hydride transfer mechanisms [4]. In the field of molecular electronics, protonation provides the possibility that electrons may be trapped in a particular redox site, thus giving rise to molecular switches [5]. In biological systems, the kinetics and thermodynamics of redox reactions are often controlled by enzyme-mediated acid-base reactions. 

In the following, the outline of the redox reaction between O2 in W and decamethyl-ferrocene in O catalysed by flavin mononucleotide (FMN) in W evolving CO2, which was elucidated by applying VCTIES, will be introduced [12,13]. The selective ion transfer controlled by the redox reaction will also be discussed. The respiration mimetic reactions such as the redox reactions between -nicotinamide adenine dinucleotide and ascorbic acid or oxygen in W and quinone derivatives or hydroquinone derivatives, respectively, were also investigated with the aid of VCTIES [14,15], though they are not introduced here. 

The emulsion overflowing from the nitrator enters the separator through a short section of pipe in which a special electrode is fitted for the measurement of the Redox-potential of the spent acid against a reference sample of mixed acid. The Redox-potential of the spent acid has a direct relation to the HNOj and HNOj content in this acid composed of lINOj-HNOj-HjO and can serve as a control on the extent that nitration follows the normal course without too many oxidation reactions and deviations from the normal course. It was first... 

Redox conditions in aquatic systems are bounded by the reactions of potential electron donors and acceptors with water, much as water buffers acid/base reactions by accepting or donating protons (Chapter 4). For example, in oxic marine systems, where dissolved O2 concentrations are measurable, the controlling redox couple (vwitten as a reduction) is O2-H2O ... 

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