Solid cathodes, synthesis

Preparation of Memfield resin-bound nitro acetates, which is a suitable bndding block for the development of combinatorial solid phase synthesis, is repotted. The anion of ethyl nitro acetate is generated in DMF by an electrochemical method using Pt cathode, magnesium rod anode, and tetrabutylairunonium bromide as an electrolyte. Alkylaton of this anion with alkyl hahdes gives mono-alkylated products in 80% yield." ... 

Leising, R.A. and E.S. Takeuchi. 1994. Solid-state synthesis and characterization of silver vanadium oxide for use as a cathode material for lithium batteries. Chem. Mater. 6 489 195. 

V. Subramanian, C. L. Chen, and H. S. Chou, Microwave-assisted solid-state synthesis of LiCo02 and its electrochemical properties as a cathode material for lithium batteries, Jottrwa/ of materials, 11(2001), 3348-3353. 

The solid-state synthesis with low grinding time may be an economically viable technique for the preparation of SOFC cathode in large scale. The reduction in the time of synthesis and energy consumption contributes significantly to the implementation of this methodology for the preparation of SOFC cathode materials. 

Yang G, Wang G, Hou W (2005) Microwave solid-state synthesis of LiV30g as cathode material for lithium batteries. J Phys Chem B 109 11186-11196... 

Kang HC, Jun DK, Jin B, Jin EM, Park KH, Gu HB, Kim KW (2008) Optimized solid-state synthesis of LiFeP04 cathode materials using ball-milling. J Power Sourc 179 340-346... 

Lee KT and Manthiram A. Synthesis and characterization of NdQjSrQ.jCOj MnyOj (0temperature solid oxide fuel cells. J. Power Sources 2006 158 1202-1208. 

Bansal NP and Zhong Z. Combustion synthesis of Sm0 5Sr0 5Co03 x and Lao 6Sr04CoO3 x nanopowders for solid oxide fuel cell cathodes. J. Power Sources 2006 158 148-153. 

Cathodic cyclization reactions have supphed and continue to provide a fertile territory for the development and exploration of new reactions and the determination of reaction mechanism. Two areas that appear to merit additional exploration include the application of existing methodology to the synthesis of natural products, and, more significantly, a systematic assessment of the factors associated with the control of both relative and absolute stereochemistry. Until there is a solid foundation to which the non-electrochemist can confidently turn in evaluating the prospects for stereochemical control, it seems somewhat unlikely that electrochemically-based methods will see widespread use in organic synthesis. Fortunately, this comment can be viewed as a challenge and as a problem simply awaiting creative solution. 

For the synthesis of materials, the reactants are placed in the copper crucible. An arc is struck by allowing the cathode to touch the anode. The current is raised slowly while the cathode is simultaneously withdrawn so as to maintain the arc. The arc is then positioned so that it bathes the sample in the crucible. The current is increased until the reactants melt When the arc is turned off, the product solidifies in the form of a button. Because of the enormous temperature gradient between the melt and the water-cooled crucible, a thin solid layer of the sample usually separates the melt from the copper hearth in this sense, the sample forms its own crucible and hence contamination with copper does not take place. Contamination of the sample by tungsten vaporizing from the cathode can be avoided by using water-cooled cathodes. The arc method has been successfully used for the synthesis of various oxides of Ti, V and Nb. A number of lower-valence rare-earth oxides, LnO, 5 have been prepared by arc fusion of LnjOj... 

E° = E°(cathode) — °(anode). standard enthalpy of combustion AHc° The change of enthalpy per mole of substance when it bums (reacts with oxygen) completely under standard conditions, standard enthalpy of formation AH° The standard reaction enthalpy per mole of compound for the compound s synthesis from its elements in their most stable form at 1 atm and the specified temperature, standard entropy of fusion ASfus° The standard entropy change per mole accompanying fusion (the conversion of a substance from the solid state to the liquid state), standard entropy of vaporization ASvap° The standard entropy change per mole accompanying vaporization (the conversion of a substance from the liquid state to the vapor state). 

Direct electrochemical synthesis is carried out according to the next procedure. Sheets of copper, nickel, or zinc are used as sacrificial anodes, and platinum is used as the cathode. Methanol is used as a solvent and LiC104 as a supporting electrolyte. The ligand (0.5 g) is dissolved in methanol (30 mL) by heating and then the obtained solution is cooled to room temperature. The electrolysis is carried out for 1 hr (current 20 mA applied voltage 20-30 V). The formed solid is filtered, washed with hot methanol (3x5 mL), and dried in air. 

In very pure nonpolar dielectric liquids, electron injection currents at very sharp tips follow the Fowler-Nordheim voltage dependence (Halpem and Gomer, 1969), just as is the case in solid insulators, and in a gas, as described before. In a study of the electrochemical behavior of CNT cathodes (Krivenko et al., 2007) direct experimental proof was found of electron emission into the liquid hexamethylphosphortriamide, which was chosen because it is a convenient solvent for the visualization of solvated electrons at room temperature the solution will show an intense blue coloration upon the presence of solvated electrons. Electron spin resonance showed prove of a free electron. Electrogenerated (as opposed to photogenerated) solvated electrons have been used in the synthesis of L-histidinol (Beltra et al., 2005), albeit that in that work the electrons were generated electrochemically from a solution of LiCl in EtNH2, which is a solvent that is easier to handle than liquid ammonia (boiling points at atmospheric pressure are 17 °C and -33.34 °C, respectively). 

Synthesis of pure hydrogen peroxide using solid polymer electrolytes (SPE) could eliminate the need to separate the product from liquid electrolytes (basic or acidic). Designs of the (SPE) fuel cell type of reactor could be investigated for such a process. Tatapudi and Fenton [71, 80] demonstrated the basic feasibility of this process (with or without concurrent anodic ozone evolution). However, new cathode materials and... 

The production of synthesis gas from methane oxidation was also studied overFe catalyst in fuel cell using solid electrolyte (YSZ) at 850-950°C at atmospheric pressure [8]. The anodic electrode was Fe and the cathode that was exposed to air was Pt. Reduced iron was more active than oxidized iron for synthesis gas formation. The maximum CO selectivity and yield were nearly 100% and 73%, respectively. Carbon deposition was reported at high methane to oxygen ration. 

Pilard, J. E Marchand, G. Simonet, J., Chemical synthesis at solid interfaces. On the use of conducting polythiophenes equipped of adequate linkers allowing a facile and highly selective cathodic s-n bond scission with a fully regenerating resin process, Tetrahedron 1998, 54, 9401-9414... 

Marchand, G. Pilard, J. F. Simonet, J., Solid phase chemistry at a modified cathode surface. First synthesis of a polyamine precursor, Tetrahedron Lett. 2000, 41, 883-885... 

Kavan [28] and Kijima et al. [29] have used the electrochemical method to synthesize carbyne. This technique may be realized by classical electrochemistry whereby the charge transfer reaction occurs at interface of a metal electrode and liquid electrolyte solution. Electrons in reaction were supplied either through redox active molecules or through an electrode, which contacts an ionically conducting solid or liquid phase and the precursor. In general, the structure and properties of electrochemical carbon may differ considerably from those of usual pyrolytic carbons. The advantage of this technique is the synthesis of carbyne at low (room) temperature. It was shown that the best product was prepared by cathodic defluorination of poly(tetrafluoroethylene) and some other perhalo-//-alkanes. The carbyne... 

Yu, X., and Licht, S. 2008. Recent advances in synthesis and analysis of Fe(VI) cathodes Solution phase and solid-state Fe(VI) syntheses, reversible thin-fihn Fe(VI) synthesis, coating-stabilized Fe(VI) synthesis, and Fe(VI) analytical methodologies. Journal of Solid State Electrochemistry 12, 1523-1540. 

Another route to nanostructured cathode materials is to tune the morphology of the solid as occurs in the synthesis of aerogels. These high surface area materials have a large pore volume and exhibit lithium capacities much higher than... 

Spectroscopic investigations also showed that the introduction of the solid alkali did not lead to an anomalous population of rotational levels in NH but raised the vibrational temperature from = 3(XK) K to c= 4000 K. It was sugg ted that the recombination of ions, presumably N, on the catalyst surface leads to an increase in the number of nitrogen molecules at high levels of vibrational excitation. However, the location of NaOH catalyst at the cathode or anode does not influence significantly either the decomposition of ammonia or the synthesis of hydrazine (Fig. 25)... 

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