Solid-phase reduction

Oxide compounds are widely used as cathodic materials in the power sources and electrochemical generators. Some literature data indicates that cathodic materials based on nonstoichiometric oxide compounds make it possible to increase the solid-phase reduction process. The kinetics of electrochemical reactions and consequently the current density are the higher, the greater the degree of deviation from stoichiometry, and the lager the number of the defects in the compounds structure [1,2]. 

Other counterions besides chloride, such as trifluoroacetate and tosylate, are also appropriate for these solid-phase reductive aminations. 

Kremer C, Leon A, Gambino D (1989) Solid-phase reduction of (Tc04)- " Tc with zinc - a method for the preparation of difficult " Tc compexes. J Labelled Comp Radiopharm 27 1331-1340 Lejeune R, Thunus J, Thunus L (1996) Polarographic determination of (Sn(II) in samples containing Sn(IV) such as in technetium-99m radiopharmaceutical kits. Anal Chim Acta 332 67-71 Lin SM, Winchell HS, Shipley BA (1971) Use of Fe(II) or Sn(II) alone for technetimn labelling of albumin. J Nucl Med 12 204-211... 

Kahn, N.M., Arumugam, V. and Balasubramanian, S. (1996) Solid phase reductive alkylation of secondary amines. Tetrahedron Lett. 37 4819-4822. 

Also solid-phase reductions with BU4NHS. 

The species of Si(I) form at the end of the non-stationary cathode reduction. They deposit onto the electrode surface resulting in the formation of the film. Elementary silicon can be obtained only at longer times when the electrode film system with appropriate properties is finally settled down and the solid-phase reduction mechanism enters its play (see Chaps. 1 and 5). If, by any chance, the elementary silicon is available in the system, then the intervalence reaction occurs with ions taking an essential part. 

In such kind of systems, the winning of a pure metal is only possible by means of a solid-phase reduction mechanism, in a FS with a high ionic conductivity. Moreover, not just ionic but predominantly anionic conductivity is required. Otherwise, the cations of the alkali metals would migrate through the film to the inner interface... 

Scheme 15 Solid Phase Reductive Cyclization Indole Synthesis and Myers 3-Alkylidene-3H-indole 1-Oxide Synthesis...

Being now a blossoming research field, solid state electrochemistry made its first steps in the last decades of the twentieth century. The development of solid phase reduction mechanism for the electrodeposition of polyvalent metals was possibly the most significant achievement of this newly emerging branch of electrochemistry. The Kiev Professor Asleksandr Tikhonovich Vas ko was among the pioneers. 

In addition to the above methods, many other methods like spray pyrolysis, flame spray p)u-olysis, electrodeposition, vapor deposition, ionic liquid, solid phase reduction, and hydro-thermal methods [32-38] have also been applied for the preparation of FC catalysts. 

Coy 1988 Coy, D.H., Hocart, S.J. and Sasaki, Y, Solid Phase Reductive Alkylation Techniques in Analogue Peptide Bond and Side-Chain Modification, Tefrahedron, 44 (1988) 835-841. 

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. 

It is known that Selenium catalyzes reaction of some dye reduction by Sulphide. On this basis spectrophotometric and test-techniques for Selenium determination are developed. Inefficient reproducibility and low sensitivity are their deficiencies. In the present work, solid-phase reagent on silica gel modified first with quaternary ammonium salt and then by Indigocarmine was proposed for Selenium(IV) test-determination. Optimal conditions for the Selenium determination by method of fixed concentration were found. The detection limit of Se(IV) is 10 ftg/L = 2 ng/sample). Calibration curve is linear in the range 50-400 ftg/L of Se(IV). The proposed method is successfully applied to the Selenium determination in multivitamins and bioadditions. 

The Zincke reaction has also been adapted for the solid phase. Dupas et al. prepared NADH-model precursors 58, immobilized on silica, by reaction of bound amino functions 57 with Zincke salt 8 (Scheme 8.4.19) for subsequent reduction to the 1,4-dihydropyridines with sodium dithionite. Earlier, Ise and co-workers utilized the Zincke reaction to prepare catalytic polyelectrolytes, starting from poly(4-vinylpyridine). Formation of Zincke salts at pyridine positions within the polymer was achieved by reaction with 2,4-dinitrochlorobenzene, and these sites were then functionalized with various amines. The resulting polymers showed catalytic activity in ester hydrolysis. ... 

Eda and Kurth applied a similar solid-phase combinatorial strategy for synthesis of pyridinium, tetrahydropyridine, and piperidine frameworks as potential inhibitors of vesicular acetylcholine transporter. One member of the small library produced was prepared from amino-functionalized trityl resin reacting with a 4-phenyl Zincke salt to give resin-bound product 62 (Scheme 8.4.21). After ion exchange and cleavage from the resin, pyridinium 63 was isolated. Alternatively, borohydride reduction of 62 led to the 1,2,3,6-tetrahydropyridine 64, which could be hydrogenated to the corresponding piperidine 65. 

Sodium reduction development directions, 336 diluted melts, 331-332 of K-Salt, 327-328 principals, 326 Solid-phase interaction mechanism, 34-37 niobium oxyfluorides, 26-31 tantalum oxyfluorides, 32-34 Solubility diagrams (NH4)5Nb3OF18, 22 K2NbF7 in HF solutions, 14 K2TaF7 in HF solutions, 14 RbsNbjOF,, 22-23 Solubility of peroxides, 307 Specific conductivity, 153, 164 Spontaneous polarization, 223 Structural characteristics for X Me=8, 61,... 

Silicon is the second most abundant element in the Earth s crust. It occurs widely in rocks as silicates, compounds containing the silicate ion, Si032, and as the silica, Si02, of sand (Fig. 14.33). Pure silicon is obtained from quartzite, a granular form of quartz (another solid phase of SiOz), bv reduction with high-purity carbon in an electric arc furnace ... 

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