Electrolytic reduction of azidochalcones

Cathodic reduction of -azidochalcones under slightly protic conditions proves to be an excellent method for a selective conversion of the azido function to an amino group without affecting other reducible parts of the molecules. The amino-propenones retain theZ-configuration about the C=C-bond of the starting material, whereas N-acetyl derivatives, obtained under mildly acetylating conditions, are partially isomerised. The low reduction potential of N,N-diacetyl-enamines of this type prevents their direct one step synthesis by electrolysis of azidochalcones under strongly acetylating conditions. The voltammetric behaviour of the azides and their reduction pathway is discussed.

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Elektrolytische Untersuchungen an Vinylaziden, 6. Mitt.Elektrolytische Reduktion von Azidochalkonen

Zusammenfassung Die kathodische Reduktion von -Azidopropenon erweist sich als ausgezeichneter Weg, um selektiv zu Enaminen zu gelangen, ohne (wie chemische Reduktionsmittel) auch andere Gruppierungen anzugreifen. Durch die Kontrolle von Protonierungs- bzw. Acetylierungsschritten lassen sich die stabileren N-Acetylamine erhalten. Das niedrig liegende Reduktionspotential der N,N-Diacetylamino-propenone verhindert, daß sie in einer Einstufensynthese bei der Reduktion der Azidochalkone unter stark acylierenden Bedingungen erhältlich sind. Das voltammetrische Verhalten der Azide und ihr Reaktionsweg bei der kathodischen Reduktion werden diskutiert.

     

Electrolytic reduction of spent oxide fuel in a molten LiCl-Li2O system

Summary The Advanced Spent Conditioning Process (ACP) developed by the KAERI is based on pyrometallurgy and the electrolytic reduction plays a central role in transforming spent oxide fuels into metals. The constituents of the spent fuels are distributed between a salt and a reduced metal phase during electrolysis. Lithium metal is produced in a molten LiCl-Li₂O cell and then it reacts with the metal oxides of the spent fuel producing Li₂O and reduced metals. By focusing on the activity of Li₂O and the electric potential, the electrolytic reduction process of the ACP is discussed. Thermodynamic considerations are defined and operation conditions are proposed including Li₂O activity and cell potential.     

Electrolytic investigations : Electrolytic determination of bismuth

An accurate method is proposed for the electrolytic determination of bismuth. The electrolysis is conducted from a nitric acid medium. It is essential that the residual nitrous acid left in the solution after dissolving the sample with nitric acid be destroyed by boiling with hydrogen peroxide, and that the electrolysis be conducted in the presence of a trace of hydrochloric acid.     

Electrolytic reduction of molybdophosphate in aqueous acetonitrile and its application to flow-coulometric determination of orthophosphate

The formation and electrolytic reduction of molybdophosphate in aqueous solutions of various water-miscible organic solvents have been extensively investigated. Acetonitrile was found to be the most useful of these solvents. Two species of molybdophosphate are formed in aqueous acetonitrile, one of which changes spontaneously into the other, which is quite stable and undergoes a 2-electron electrolytic reduction. On the basis of these facts, a flow-coulometric method for orthophosphate has been developed, applicable to the range 5 × 10⁻⁶-1 × 10⁻³M. It has been used for determination of orthophosphate in several phosphorus compounds, some of which are acid-labile.     

Electrolytic reduction of Tc(VII) in nitric acid solution using glassy carbon electrode

Electroreduction of Tc(VII) was studied in nitric acid solution using glassy carbon electrode. The electroreduction was conducted at a constant potential –300 mV (vs. Ag/AgCl) with a potentiostat. It was found that the difference of the Tc concentration in the solutions before and after the electrolysis was negligibly small. This means that there were almost no TcO₂ or Tc deposited on the carbon fiber electrode during the electroreduction. Absorption spectra and distribution coefficients obtained by ion-exchange analysis indicated that Tc(VII) was reduced to Tc(IV).This work was financed by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) under the framework of The Development of Innovative Nuclear Technologies.     

Electrolytic reduction of Tc(VII) in nitric acid solution using glassy carbon electrode

Electroreduction of Tc(VII) was studied in nitric acid solution using glassy carbon electrode. The electroreduction was conducted at a constant potential –300 mV (vs. Ag/AgCl) with a potentiostat. It was found that the difference of the Tc concentration in the solutions before and after the electrolysis was negligibly small. This means that there were almost no TcO₂ or Tc deposited on the carbon fiber electrode during the electroreduction. Absorption spectra and distribution coefficients obtained by ion-exchange analysis indicated that Tc(VII) was reduced to Tc(IV).This work was financed by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT) under the framework of The Development of Innovative Nuclear Technologies.     

Electrolytic reduction of 2-butyne-1,4-diol as a route to trans-2-butene-1,4-diol

The effect of the cathode material on the electrochemical transformations of 2-butyne-1,4-diol at atmospheric pressure was studied by chromatographic analysis. The optimal parameters of the selective synthesis of trans-2-butene-1,4-diol were determined.     

Electrolytic Co3O4 for thin-layer anodes of lithium-ion batteries

Electrolytic (e) cobalt oxide of a spinel structure, e-Co₃O₄, is obtained from the sulfate and nitrate (aqueous, water-alcohol) solutions containing Co²⁺ with the aim of using it in thin-layer anodes of lithium-ion batteries. The physicochemical and structural properties of the synthesized compounds are examined using thermal and x-ray diffraction analyses, absorption IR spectroscopy, and atomic force microscopy. The electrochemical characteristics of e-Co₃O₄ are determined in breadboards of lithium power sources and in the lithiumion system LiCoO₂/e-Co₃O₄.     

Electrolytic behavior of SrCl2 and BaCl2 in LiCl molten salt during oxide reduction in pyroprocessing

Journal of Radioanalytical and Nuclear Chemistry - Ba and Sr elements in spent nuclear fuels are supposed to accumulate in LiCl molten salt electrolyte by forming chlorides (i.e., BaCl2, SrCl2)...     

电导率和摩尔电导率与浓度关系的教学讨论

根据电导率和摩尔电导率的物理意义,通过简单计算,确定了参与导电的离子数目与电解质溶液浓度或电离度之间的关系,由此分析说明了电导率和摩尔电导率与电解质浓度的关系。方法简单清晰,便于学生领会理解。     

Electrolytic99TcO 4 − reduction at inert electrodes: An alternative synthetic route to Tc complexes

Electrolytic pertechnetate reduction at inert electrodes was studied as an alternative procedure for synthesizing Tc complexes. Pertechnetate reduction was carried out in aqueous media using different aminated ligands /en, dien, trien and 1,3-dap/ forming [TcO₂/amine/₂]⁺ type complexes. Simultaneously with synthesis of the desired Tc complex, TcO₂ was electrodeposited onto the cathode. Conversion of TcO ₄ ^– to Tc complex and TcO₂ was studied as a function of several variables /kind and concentration of supporting electrolyte, ligand concentration, pH, current and electrolysis time/.     

Electrolytic methoxylation of halognofurans

-Halogenofurans are electrolytically methoxylated in two ways in the presence of sulfuric acid electrolyte, methoxyl groups either adding at the 2 and 5 positions in the furan ring or replacing a ring halogen atom. The following are methoxylated: 2-bromo-, 2-iodofuran, 5-chloro-, 5-bromo-, and 5-iodofurfural, ethyl 5-bromopyromucate. Derivatives of 2, 2, 5-trimethoxy-2, 5-dihydrofuran are prepared, giving on hydrolysis-aldehydo- and-ketoacrylic acids.Total anode polarization graphs are obtained in order to study the electrolytic methoxylation reaction mechanism.Furfural and 2-acetylfuran methoxylate, but only after first undergoing conversion to the dimethylacetal [1, 2].Electrolytic methoxylation of furan derivatives using sulfuric acid as electrolyte was first applied to methoxylation of a pyromucic ester, which, as referred to above, is not methylated using ammonium bromide.     

Electrolytic investigations : Electrolytic determination of silver after a silver chloride precipitation

A procedure is described for determining silver electrolytically after first precipitating the silver as silver chloride. The silver chloride is filtered through a filter paper, and the filter paper and precipitate are treated with a mixture of perchloric, sulfuric, and nitric acids. The solution is then evaporated to fumes of sulfuric acid, and the silver determined electrolytically by the cyanide method.     

Low-temperature vacuum reduction of BiMnO3

Low-temperature vacuum reduction was used for the preparation of the oxygen-deficient BiMnO(2.81) sample in a bulk form from stoichiometric BiMnO(3). The transformation occurs in vacuum better than 10(-3) Pa at a narrow temperature range of 570-600 K. The structure of the new phase was analyzed using synchrotron X-ray powder diffraction data. BiMnO(2.81) crystallizes in a perovskite-type cubic structure (space group I-43d) with a = 15.88552(5) ? corresponding to a 4a(p) superstructure, where a(p) is the parameter of the cubic perovskite subcell. Oxygen vacancies are ordered, and one oxygen site in BiMnO(2.81) is completely vacant, resulting in MnO(5) pyramids. BiMnO(2.81) is rather unstable in air and slowly restores its oxygen content even at room temperature.     

Biocatalytic asymmetric reduction of 3-acetylisoxazoles

The reduction of the carbonyl group in 3-acetylisoxazole derivatives by algae (Cyanobacterium: Synechococcus elongatus PCC 7942 and Synechosystis sp. PCC 6803) and plant cells (Caragana chamlagu) gave the corresponding (S)-alcohols with high enantioselectivities.     

间接电解氧化法制备环己酮

提出了一种合成环己酮的新方法－－间接电氧化合成法。在无隔膜装置中用Pb/PbO2作阳极，Pt作阴极将Cr^3 氧化成Cr2O7^2-，然后以Cr2O7^2-为氧化剂对环己醇进行氧化而获得环己酮，还原所得Cr^3 循环利用。电解的优选条件为：电解液浓度C（H2SO4）＝3.0mol/L-4.0mol/L,C(Cr^3 )=0.3mol/L-0.45mol/L，温度t=55℃－65℃，电流密度约643A／m^2。此时Cr^3 的转化率为70％左右，电流效率可达72％。