Reduction organic

Reactions. Although lithium aluminum hydride is best known as a nucleophilic reagent for organic reductions, it converts many metal haUdes to the corresponding hydride, eg, Ge, As, Sn, Sb, and Si (45). 

THE SOLID-PHASE REAGENTS FOR THE DETERMINATION OF PHOSPHORUS AND ORGANIC REDUCTANTS... 

Unloaded silica does not recover HPA from aqueous solution. The surface of silica gel modified with quarternary ammonium salts (QAS) gets anion-exchange properties. The aim of the work is the elaboration of solid-phase reagents on the base of ion associate of HPA with QAS immobilized onto silica surface for the determination of phosphoms and organic reductants. Heterocyclic (safranine and lucigenine) and aliphatic (trinonyloctadecyl ammonium iodide and tetradecyl ammonium nitrate) compounds have been examined as QAS. 

Although some metal cations and oxyanions can serve as electron acceptors for growth under anaerobic conditions, reduction may also take place gratuitously, and these reductases have been characterized in a number of organisms. Reduction has been implicated in resistance to metal cations and metalloid oxyanions, which are discussed in Part 4 of this chapter. 

Of more intrinsic interest are processes involving two electrons, since these constitute the great bulk of organic reductive processes, especially in protonic solvents. The reason for this is that the first electron transfer will generate an unstable radical species, whereas the second can regenerate a stable closed-shell product. One example that we have already encountered is C02 reduction but a case that has been well studied is that of quinone reduction as ... 

The applications of polyoxometalates in catalytic dehalogenation of halocar-bons have been succinctly reviewed by Hill and coworkers [188]. This reaction involves the photocatalytic transformation of organic halides coupled with the oxidation of sacrificial organic reductants (secondary alcohols or tertiary amides) (Eq. (9)) [189, 190] ... 

A typical redox reaction sequence between an (usually organic) reductant R and iron(III) (hydr)oxide can be schematically expressed as... 

Reductive dissolution of iron(III)(hydr)oxides and reduction of dissolved iron(III) species by organic reductants, R, soluble reduced sulfur or solid phase sulfur, S(—II)-... 

Adsorption of Organic Reductants and Subsequent Electron Transfer on Metal Oxide Surfaces... 

Reductive dissolution of transition metal oxides by organic reductants can be described as occurring in the following sequence of steps (i) diffusion of reductant molecules to the oxide surface,... 

STONE Adsorption of Organic Reduct ants and Electron Transfer... 

Relatively little is known about the speciation of organic compounds, and organic reductants in particular, when adsorbed to metal oxides. It is known that surface coverage is higher for bidentate organic ligands, such as catechol and salicylate, than... 

Consider, for example, an organic reductant that forms protonated (>MeAH), neutral (>MeA) and outer-sphere (>MeOH, HA) surface complexes. R.2, the rate of electron transfer, is determined by how quickly electron transfer occurs within each type of complex. 

Few studies have systematically examined how chemical characteristics of organic reductants influence rates of reductive dissolution. Oxidation of aliphatic alcohols and amines by iron, cobalt, and nickel oxide-coated electrodes was examined by Fleischman et al. (38). Experiments revealed that reductant molecules adsorb to the oxide surface, and that electron transfer within the surface complex is the rate-limiting step. It was also found that (i) amines are oxidized more quickly than corresponding alcohols, (ii) primary alcohols and amines are oxidized more quickly than secondary and tertiary analogs, and (iii) increased chain length and branching inhibit the reaction (38). The three different transition metal oxide surfaces exhibited different behavior as well. Rates of amine oxidation by the oxides considered decreased in the order Ni > Co >... 

Electron transfer between metal centers can alter the course of reaction in several ways (46). Thermal excitation may create especially reactive electron holes on the oxide surface, causing reductant molecules to be consumed at the surface at a higher rate. More importantly, electrons deposited on surface sites by organic reductants may be transferred to metal centers within the bulk oxide (47). This returns the surface site to its original oxidation state, allowing further reaction with reductant molecules to occur without release of reduced metal ions. Electron transfer between metal centers may therefore cause changes in bulk oxide composition and delay the onset of dissolution. 

Biochemical- -cellular Detoxification Membrane disruption Adaptation of organism Reduction In condition of... 

The organic reduction process also termed the aniline, laux or nitrobenzene process. This method leads to black, yellow or red pigments. 

An aqueous solution of chromium(ll) chloride for organic reduction may be prepared as follows ... 

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