By Electrochemical Reduction

Diphenyl ditellurium was electrochemically reduced to benzenetellurolate in acetonitrile with sonication in an H-type cell. Tetrabutylammonium hexafluorophosphate served as the electrolyte. The cathode was a cylindrical graphite cloth and the anode a platinum grid. The cathodic solution was purged with argon. The potential had to be changed from — 1.20 to — 2.35 V during the reduction  

Azobenzene or l,2-di(4 -pyridyl)ethene was used as a reduction catalyst. The generated benzenetellurolate was employed in the synthesis of cyanophenyl phenyl tellurium compounds and of benzoylphenyl phenyl tellurium compounds.  

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Electrowinning from Aqueous Solutions. Electrowinriing is the recovery of a metal by electrochemical reduction of one of its compounds dissolved in a suitable electrolyte. Various types of solutions can be used, but sulfuric acid and sulfate solutions are preferred because these are less corrosive than others and the reagents are fairly cheap. From an electrochemical viewpoint, the high mobiUty of the hydrogen ion leads to high conductivity and low ohmic losses, and the sulfate ion is electrochemicaHy inert under normal conditions. 

New Synthesis. Many attempts have been made to synthesize oxaUc acid by electrochemical reduction of carbon dioxide in either aqueous or nonaqueous electrolytes (53—57). For instance, oxaUc acid is prepared from CO2 as its Zn salt in an undivided ceU with Zn anodes and stainless steel cathodes ia acetonitrile containing (C4H2)4NC104 and current efficiency of >90% (53). Micropilot experiments and a process design were also made. 

In the reduction of nitro compounds to amines, several of the iatermediate species are stable and under the right conditions, it is possible to stop the reduction at these iatermediate stages and isolate the products (see Figure 1, where R = CgH ). Nitrosoben2ene [586-96-9] C H NO, can be obtained by electrochemical reduction of nitrobenzene [98-95-3]. Phenylhydroxylamine, C H NHOH, is obtained when nitrobenzene reacts with ziac dust and calcium chloride ia an alcohoHc solution. When a similar reaction is carried out with iron or ziac ia an acidic solution, aniline is the reduction product. Hydrazobenzene [122-66-7] formed when nitrobenzene reacts with ziac dust ia an alkaline solution. Azoxybenzene [495-48-7], C22H2QN2O, is... 

Deuteration by Electrochemical Reduction of a Steroidal Ketone in the Presence of Deuterium Oxide-10% Deuterio-sulfuric Acid... 

Deuteration by electrochemical reduction of a steroidal ketone in the presence of deuterium oxide-10% deuterio-sulfuric acid, 168... 

It has recently been reported that a molecule, claimed to contain a high concentration of conjugated alkyne units, can be prepared by electrochemical reduction of polytetrafluoroethylene (PTFE) [32,33]. The reduction is carried out using magnesium and stainless steel as anode and cathode respectively. The electrolyte solution contains THE (.30 cm ), LiCI (0.8 g) and FeCl2 (0.48 g). A 10 X 10 nm PTFE film, covered with solvent, is reduced to carbyne (10 V for 10 h)... 

Fig. 3.6 EPR spectmtn of the radical anion [PhC(NSN)2CPh] generated by electrochemical reduction." ...

The picolinamide is prepared in 95% yield from picolinic acid/DCC and an amino acid and is hydrolyzed in 75% yield by aqueous Cu(OAc)2 or by electrochemical reduction (sulfuric acid, MeOH, 20°, 20-94% yield)."... 

Electrodeposition deposition of a metal or alloy onto a substrate by electrochemical reduction of its ions from an electrolyte under the application of a cathodic overpotential. 

Although one of the most common storage batteries is called the nickel/cadmium system ( NiCad ), correctly written (-)Cd/KOH/NiO(OH)(+), cadmium is not usually applied as a metal to form a battery anode. The same can be said with regard to the silver/cadmium [(-) Cd / KOH / AgO (+)] and the MerCad battery [(-)Cd/KOH/HgO(+)]. The metallic negative in these cases may be formed starting with cadmium hydroxide, incorporated in the pore system of a sintered nickel plate or pressed upon a nickel-plated steel current collector (pocket plates), which is subsequently converted to cadmium metal by electrochemical reduction inside the cell (type AB2C2). This operation is done by the customers when they start the application of these (storage)... 

Although in neither case is the E(II) product well characterized, GaMe3 is reduced by Na in liq NH3 to Na2[Ga2Me6] " , and TlMcj by K-NHj to K2[Tl2Me5]". Attempts to obtain T1—Tl-bonded compounds, e.g., Tl2Ph4, by electrochemical reduction of diorganothallium(III) derivatives do not succeed -. ... 

Chiang and coworkers synthesized a dimer of compound 26 in which two diiron subunits are linked by two azadithiolate ligands as a model of the active site for the [FeFeJ-hydrogenase [203]. Protonation of 26 afforded the p-hydride complex [26-2H 2H ] via the initially protonated spieces [26-2H ] (Scheme 62). These three complexes were also characterized by the X-ray diffraction analyses. H2-generation was observed by electrochemical reduction of protons catalyzed by 26 in the presence of HBF4 as a proton source. It was experimentally ascertained that [26-2H 2H ] was converted into 26 by four irreversible reduction steps in the absence of HBF4. 

In 2009, Rauchfuss and coworkers succeeded in the synthesis of the Fe- i-H-Ni complex [(CO)3Fe(pdt)(p-H)Ni(dppe)]BF4 28 (pdt = 1,3-propanedithiolate, dppe = 1,2-C2H4(PPh2)2) as a model for [NiFeJ-hydrogenases (Scheme 64) [212]. The structure of 28 was characterized by X-ray crystallographic analysis. This is the first example of an Fe-Ni thiolato hydride complex. Evolution of H2 by electrochemical reduction of CF3CO2H (pXa = 12.65) was observed in the presence of the catalytic amounts of 28. 

Fig. 10. Pseudorotaxane-terminated dendrimers generated by electrochemical reduction...

Porous aluminum oxide can be used as a template for the production of nanowires and nanotubes. For example, metals can be deposited on the pore walls by the following procedures deposition from the gas phase, precipitation from solution by electrochemical reduction or with chemical reducing agents, or by pyrolysis of substances that have previously been introduced into the pores. Wires are obtained when the pore diameters are 25 nm, and tubes from larger pores the walls of the tubes can be as thin as 3 nm. For example, nanowires and nanotubes of nickel, cobalt, copper or silver can be made by electrochemical deposition. Finally, the aluminum oxide template can be removed by dissolution with a base. 

Low-valent lanthanides represented by Sm(II) compounds induce one-electron reduction. Recycling of the Sm(II) species is first performed by electrochemical reduction of the Sm(III) species [32], In one-component cell electrolysis, the use of sacrificial anodes of Mg or A1 allows the samarium-catalyzed pinacol coupling. Samarium alkoxides are involved in the transmet-allation reaction of Sm(III)/Mg(II), liberating the Sm(III) species followed by further electrochemical reduction to re-enter the catalytic cycle. The Mg(II) ion is formed in situ by anodic oxidation. SmCl3 can be used in DMF or NMP as a catalyst precursor without the preparation of air- and water-sensitive Sm(II) derivatives such as Sml2 or Cp2Sm. 

There seems to be an opportunity to extend the electrochemical process to direct membrane transport that is, with electrodes plated on either side of a facilitated-transport membrane similar to that of Johnson [24]. The shuttling action of the carrier (Fig. 9) could then be brought about by electrochemical reduction and oxidation instead of pressure difference. 

Products Obtained by Electrochemical Reduction of Carbon Dioxide under High Pressure of 10 kg/cm2 Gagea... 

The conversion of nitroalkenes into the oximes can be achieved by electrochemical reduction (Eq. 6.60).11[Pg.176]

The iV-( -nitrophcnyl)pipcrazinc-2-carbonitrilc 251 (Y = NBOC) was reductively cyclized to the tricyclic /V-oxides 252 (Y = NBOC) either by catalytic hydrogenation, or by electrochemical reduction. Electrochemical reduction gave lower yield. Compounds 251 were prepared by electrochemical cyanation of the iV-(o-nitrophenyl)piperazine 250. The jV-oxides 252 were further hydrogenated to the 2,3,4,4 ,5,6-hexahydro-l//-pyrazino[l,2- ]quinoxaline 253 (Y = NBOC) (Scheme 46) <2001EJ0987>. 

Although more hydrolytically sensitive than the phosphine boranes, diorganochlorophosphines can be more accessible than diorganophosphines and are not pyrophoric. Thus, the reaction of a chlorophosphine with an aryl halide or aryl triflate in the presence of zinc as a reducing agent and (DPPE)NiCl2 as catalyst provides a convenient procedure for P—C coupling (Equation (49)).150 A related nickel-catalyzed process driven by electrochemical reduction has also been reported 151... 

The [MoOI(prP4)] precursor 3 was finally converted to the corresponding dinitrogen complex by electrochemical reduction with a Hg pool electrode in the presence of dinitrogen and phenol. The latter reagent was added as a weak acid to induce protonation of the oxo group and subsequent elimination as water. The blue solution of the Mo oxo complex thereby turned... 

Thermodynamically, chromium deposition can occur by electrochemical reduction or chemical dissociation of high valent chromium species. Thus, the focus of the debate on the deposition of chromium during the 02 reduction on LSM based... 

The results show that the deposition of Cr species is not dominated by electrochemical reduction of high-valent chromium species in competition with 02 reduction. The driving force for the deposition reaction was suggested to be related to the... 

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