Inorganic reduction

The inorganic reductions of NaBH are numerous and varied (Table 7). Comparatively few anions are reduced, yet the reduction of bisulfite to dithionite (hydrosulfite) (25), which is used in the pulp (qv) and paper (qv), clay (see Clays), and vat dyeing industries, is an important inorganic appHcation ofNaBH,. 

Table 7. Summary of Inorganic Reductions by Sodium Borohydride ...

OCV conditions, by a newly formed SEI is expected to be a slow process. The SEI is necessary in PE systems in order to prevent the entry of solvated electrons to the electrolyte and to minimize the direct reaction between the lithium anode and the electrolyte. SEI-free Li/PE batteries are not practical. The SEI cannot be a pure polymer, but must consist of thermodynamically stable inorganic reduction products of... 

Redox reactions are of importance in the dissolution of Fe-bearing minerals (Table 9.1). Reductive dissolution of Fe(III)(hydr)oxides can be accomplished with many reductants, especially organic and inorganic reductants, such as ascorbate, phenols, dithionite, HS, etc. Fe(II) in presence of complex formers can readily dissolve... 

The pattern for outer-sphere oxidation by Co(NH3)5 compared with Co(en)j+ (usually it is —10 times slower) towards inorganic reductants can be used to support an estimate of the proportion of electron transfer (Marcus-dependent) and charge transfer which Ru(bpy) + displays towards these oxidants (45 and 11%, respectively). Sec. 2.2.1(b). Finally, Eqn. 5.35 can be used to determine K 2 for a reaction in which the other kinetic parameters are known. The value of A, 2 can be used, in turn, to estimate the oxidation potential of one couple, which is normally inaccessible. Thus the potentials of the o-, m- and /7-benzene diol radicals 1T2A4 were determined from kinetic data for the oxidation of the diols (H2A) by Fe(phen) + (5.45) ... 

Since the stable product of oxidation by Cr(VI) is Cr(III) we are necessarily involved with three-electron reactions, with their attendant interests and eomplications. For inorganic reductants, R oxidized to O, the reaction scheme (1.118) holds... 

For a number of inorganic reductants, the second step is rate-limiting and... 

A number of second-order reactions with inorganic reductants have been studied. When the reductant has ligand properties, for example, CjOj", Br or HN3, reaction is considered to... 

Figure 4.15 indicates the range of rates of O2 consumption in different soils. Oxygen is consumed in oxidation of inorganic reductants, such as Fe(II), as well as in oxidation of organic matter by microbes. Bouldin (1968) and Howeler and Bouldin (1971) compared measured rates of O2 movement into anaerobic soil cores with the predictions of various models, and obtained the best fits with a model allowing for both microbial respiration and abiotic oxidation of mobile and immobile reductants abiotic oxidation accounted for about half the O2 consumed. The kinetics of the abiotic reactions are complicated. They often depend on the adsorption of the reductant on solid surfaces as, for example, in... 

Mobile inorganic reductants in the soil are oxidized, particularly Fe which is precipitated as Fe(OH)3 on or near the root. As a result the concentration of Fe + near the root falls and more Fe " " diffuses in from the bulk soil. This is then oxidized resulting in a zone of Fe(OH)3 accumulation near the root. The oxidation of inorganic reductants generates H+ ... 

The combination of a variety of inorganic reductants and inorganic oxidants initiates radical polymerization, for example... 

Shoute, L. C. T., Z. B. Alfassi, P. Neta, and R. E. Huie, Temperature Dependence of the Rate Constants for Reaction of Dihalide and Azide Radicals with Inorganic Reductants, J. Phys. Chem., 95, 3238-3242 (1991). 

In addition to these inorganic reduction processes, biological reduction processes by phytoplankton yielding either inorganic As(III) or various organic As(III) species were shown to be important in marine environments (70, 71). These processes are important in the photosynthetically productive layers of the lake. Microbial processes causing the reduction of As(V) under anaerobic conditions are poorly known. 

Reductive dissolution of transition metal oxide/hydroxide minerals can be enhanced by both organic and inorganic reductants (Stone, 1986). There are numerous examples of natural and xenobiotic organic compounds that are efficient reducers of oxides and hydroxides. Organic reductants associated with carboxyl, carbonyl, phenolic, and alcoholic functional groups of soil humic materials are one example. However, large... 

It was also found that there exists a s mergic effect in the organic oxidation and inorganic reduction. Some studies show that the presence of some metal ions can affect the rate of oxidation of organic molecules. For instance, the rate of oxidation of phenol can be affected by the presence of silver (Huang et al., 1996) and silver can also affect the oxidation of textile dyes (Sokmen and Ozkan, 2002). The presence of Cr(VI) affects the rate of oxidation of salicylic acid (Colon et al., 2001). 

Blood, breast milk (total, inorganic) Digestion of sample with nitric/perchloric acid overnight for total, and with H2S04 overnight for inorganic reduction and purging CVAAS 0.1 ng/g (blood) 0.04 ng/g (milk) 97% Oskarsson et al. 1996... 

Water, sea water (inorganic) Reduction of mercury in sample with SnCI2 preconcentration onto platinum-lined graphite tube GFAAS <2 ng/L 94-102 Baxter and French 1989... 

Figure 28. Hypothetical anaerobic nitrogen cycle based on the following thermodynamically permissible reactions (1) ammonium oxidation to dinitrogen by carbon dioxide,. sulfate or ferric iron (no evidence at present, possibly kinetically limited) (2) dinitrogen fixation by various organic and inorganic reductants (known) (3) ammonium oxidation by nitrite or nitrate producing dinitrogen (known) (4) denitrification (known) (5) nitrite or nitrate respiration (known) (6) ferric iron oxidation of ammonium to nitrite or nitrate (no evidence at present) (7) nitrate assimilation (known) (8) ammonium assimilation and di.s,similation (known) (Fenchel etai, 1998).

Dinitrogen fixation by various organic and inorganic reductants ... 

Cytochrome Systems Linking Inorganic Reductants to Molecular Oxygen... 

Rhenium sulfides are effective catalysts for hydrogenation of organic substances and they have the advantage over heterogeneous platinum metal catalysts in that they are not poisoned by sulfur compounds.811 An inorganic reduction that they catalyze is that of NO to N20 at 100°.8b... 

---