共查询到20条相似文献,搜索用时 31 毫秒
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Coulometric generation of acetyl (CH3CO+) ions by oxidation of mercury in acetic anhydride and in acetic acid/acetic anhydride (5:95, v/v) is described. Current/potential curves for solvents, titrated bases, indicator and mercury showed that in both these solvents mercury is oxidized at potentials which are much more negative than those for the titrated bases and other components present in the solution. Quinoline, triethanolamine, triethylamine, pyridine and quinolin-8-ol in acetic anhydride, as well as triethylamine, 2,2′-bipyridine, 2,4,6-collidine, pyridine and sodium acetate in acetic acid/acetic anhydride were titrated with acetyl ions generated by the oxidation of mercury. In this way, it was established that the oxidation of mercury to mercury (I) ions proceeds quantitatively with 100% current efficiency. 相似文献
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F.M. Triebe James H. Barnes M.Dale Hawley Richard N. McDonald 《Tetrahedron letters》1981,22(51):5145-5148
Cyclic voltammetric studies of the reduction of diphenyldiazomethane (Ph2CN2) in CH3CN-Me4NPF6 at a hanging mercury drop electrode have established that the halflife of Ph2CN2? is less than l ms at either 8°C or ?37°C. 相似文献
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The palladium-catalysed co-oligomerisation of butadiene with acetic acid in the presence of various phosphites has been studied. It has been found that the use of ortho-alkyl or ortho-aryl substituted triaryl phosphites as ligands enables almost quantitative yields of acetoxyoctadienes to be obtained. Furthermore a significant degree of control of isomer ratios can be achieved. 相似文献
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The electroreduction of camphorquinone in DMF, at mercury electrodes, was investigated by a variety of techniques. In DMF, in the absence of proton donor, camphorquinone exhibits two one-electron waves: the first, a one-electron reversible wave to be due to a reversible charge transfer without a coupled chemical reaction. After the first charge transfer, the semidione anion radical is reduced to the dianion. The irreversibility of the second wave derives from a fast irreversible protonation of the dianion. A wide variety of changes in behaviour is observed in the reduction of camphorquinone as increasing amounts of benzoic acid are added: a new two-electron irreversible wave appears at a potential less negative than the original wave. A proton donor to substrate ratio of 2 is required to completely suppress the two original waves. A mechanism for the electroreduction of camphorquinone is proposed and discussed on the basis that the prewave current is controlled by the diffusion of the undissociated acid species and that the undissociated acid, rather than the solvated proton, takes part in the protonation, prior to the charge transfer. 相似文献
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《Electrochemistry communications》2008,10(7):970-972
We report on oxygen reduction in a physiological buffer solution (0.05 M phosphate buffer containing dissolved O2, 0.1 M NaCl, pH 7.4, 37 °C) by Melanocarpus albomyces laccase, co-immobilized with [Os(2,2’-bipyridine)2(polyvinylimidazole)10Cl]+/2+ as a mediator, on glassy carbon electrodes. Such oxygen cathodes yielded current densities of 3.8 mA cm−2 at 0.2 V vs. Ag/AgCl, the largest current density reported to date for a mediated laccase cathode in physiological buffer solutions, showing promise for development of biocatalytic fuel cell prototypes. 相似文献
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N. I. Kuznetsova A. F. Danilyuk V. A. Likholobov Yu. I. Yermakov 《Reaction Kinetics and Catalysis Letters》1979,12(3):235-239
Data are reported on variations of the gas phase volume and product accumulation in ethylene oxidation by lithium nitrate in acetic acid solutions, catalyzed by palladium acetate. An assumption is made on the routes of nitrate ion reduction.
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Ferroin cannot be used as an indicator in perchloric acid medium because of precipitation of ferroin perchlorate. There is no precipitation, however, if the solution contains 30%(v/v) of acetic acid. 相似文献
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《Journal of Electroanalytical Chemistry》1986,213(1):65-73
The anodic oxidation of mercury in the presence of methylthioacetic acid (MTA = HL) has been studied by several electrochemical techniques including polarography, cyclic voltammetry, coulometry, differential capacity curves, and potentiostatic and galvanostatic transients. MTA yields a first signal corresponding to the diffusion-controlled formation of the soluble Hg2L2 compound. At more positive potentials a current spike appears, which is assigned to the two-dimensional nucleation and growth of an insoluble Hg2L+ compound. 相似文献
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Cinnamic acids have been prepared in moderate to high yields by a new direct synthesis using aromatic aldehydes and aliphatic carboxylic acids, in the presence of boron tribromide as reagent, 4-dimethylaminopyridine (4-DMAP) and pyridine (Py) as bases and N-methyl-2-pyrolidinone (NMP) as solvent, at reflux (180-190 degrees C) for 8-12 hours. 相似文献
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L. M. Korotaeva T. Ya. Rubinskaya L. V. Mikhal’chenko I. A. Rybakova V. P. Gul’tyai 《Russian Journal of Electrochemistry》2011,47(10):1139-1145
The electrochemical behavior of cinnamic acid (CA) on the cathodes with a high hydrogen overpotential (Hg, glassy carbon, and carbositall) in the aprotic solvent (DMF) and in DMF with additions of H2O or Et4NOH is studied by the methods of polarography, preparative electrolysis, cyclic voltammetry (CVA), coulometry, and chronoammetry. It is found that the mechanism of CA electroreduction is in conflict with the classical notion of the mechanism of electroreduction of α,β-unsaturated carboxyl compounds. It is shown that in the aprotic solution, in contrast to similar carbonyl compounds or ethers, which are the derivatives of organic acids, the products of double-bond hydrogenation, rather than the dimeric compounds, are the only products of CA electroreduction, i.e the presence of carboxyl group changes essentially the direction of electrochemical process. From the data of CVA, it is concluded that stable dimeric associates are present in the DMF solutions in the equilibrium with nondissociated CA. 相似文献
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An investigation has been conducted into the staged synthesis of 2-methylimidazole from ethylenediamine and acetic acid in the presence of a bifunctional aluminoplatinum catalyst. It has been shown that the formation stage of 2-methylimidazoline occurs more quickly on -Al2O3 than its dehydrogenation on the Pt centers. From a comparison of the processes of dehydrogenation of 2-methylimidazoline in the molten phase and in aqueous solution it follows that the water eliminated in the imidazoline formation stage could cause the decrease in activity during the dehydrogenation on the Pt centers. The structures of the secondary and intermediate products have been established for each stage of the process and their formation routes are discussed.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 9, pp. 1997–2002, September, 1992. 相似文献
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Pitting behavior on super 13Cr stainless steel in 3.5% NaCl solution in the presence of acetic acid 总被引:1,自引:0,他引:1
Z. F. Yin W. Z. Zhao W. Tian Y. R. Feng C. X. Yin 《Journal of Solid State Electrochemistry》2009,13(8):1291-1296
The pitting behavior was investigated on super 13Cr stainless steels in 3.5% NaCl solution in the presence of HAc. The electrochemical
measurements including potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and chronoamperometric
experiments were carried out, as well as the SEM surface analysis. The parameters such as E
corr and I
corr were obtained by fitting technique. Moreover, the equivalent circuit model was applied in the analysis of Nyquist plots,
and ZsimWin software was used to analyze the EIS data. The results indicate that the pitting corrosion is accelerated with
increasing the amounts of HAc. In addition, pitting nucleation and growth mechanisms were described in this work. 相似文献