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361.
One‐electron reduction of phenosafranine (PS+ 3,7‐diamino‐5‐phenylphenazinium chloride), a phenazinium dye, has been studied in homogeneous aqueous and sodium dodecyl sulfate (SDS) micellar media, using the pulse radiolysis technique. The various reducing radicals employed for the study in homogeneous aqueous medium were eaq?, H˙, CO2,˙?, and isopropyl ketyl radicals (CH3)2 ˙COH. Semireduced species generated by these reactions have been characterized by their absorption spectra, decay kinetics, and pKa. The one‐electron reduction potential of PS+ was determined at pH 7 in homogeneous aqueous solution employing nitrobenzene (NB/NB˙?) as the standard couple. One‐electron reduction in SDS micellar medium and a detailed spectrophotometric investigation of the parent dye in this surfactant system was carried out in order to understand the dye–surfactant interactions in the micellar and premicellar media.© 2001 John Wiley & Sons, Inc. Int J Chem Kinet 34: 56–66, 2002 相似文献
362.
P. K. R. Nair A. Mittal S. V. Kadamne K. Srinivasulu 《Reaction Kinetics and Catalysis Letters》1982,19(1-2):201-205
Oscillatory behavior in the uncatalyzed aqueous acidic bromate oxidation of 3,4-dimethoxybenzaldehyde (veratraldehyde) is reported. The generally used H2SO4 can be substituted by HNO3, HClO4, CCl3 COOH and H3PO4 in this system. The length of the induction period is found to be dependent on the initial concentrations of the reagents and this effect is more prominent in the case of acidity. The precipitate accumulated in the reaction during oscillations has been identified. A plausible mechanism is also suggested. Experiments with allyl alcohol, a bromine scavenger, suggest that elemental bromine formed in the reaction has a role in the mechanism together with or besides bromide inons.
3,4- () . H2SO4 HNO3, HClO4, CCl3 COOH H3PO4 . . , , . . , , , , , .相似文献
363.
In an attempt to synthesise azuleno[2,1-a]azulene (1), Cu+ ion-catalysed reaction of diazomethane with 3,6,7,8-tetrahydrodibenzopentalene (4) has been investigated. Addition occurred to only one of the aromatic rings to give chiefly 1,2-benzo-4,5-cycloheptatrieno-3,6,7,8-tetrahydropentalene (13/14). Dehydrogenation of 13/14 to 11H-indeno[2.1-a]azulene has been carried out. 相似文献
364.
The transient optical absorption bands formed at λmax=340 and 435 nm, on reaction of √OH radicals in aerated acidic aqueous solutions of 1,1,1-trifluoro-2-iodoethane at low and high solute concentration, have been assigned to monomer and dimer radical cations, respectively. The deprotonation of the solute radical cations is the rate-determining step for the decay of the dimer radical cations. The stability constant for the dimer radical cation is determined to be 50 dm3 mol−1 at 25°C. The dimer radical cation is a strong one-electron oxidant. Quantum chemical calculations and experimental results confirm that fluorine reduces the electron density at iodine and the √OH-radical-induced oxidation of fluoroiodoalkanes becomes a difficult process compared to iodoalkanes. 相似文献
365.
Summary It has been shown that Cu, Hg, Sb, Bi, Se, Te, Au, Pt and Pd precipitated from their compounds in elementary form and thus be determined gravimetrically by vanadium(II) sulphate solution.
Part II: Z. analyt. Chem.189, 406 (1962). 相似文献
Zusammenfassung Cu, Hg, Sb, Bi, Se, Te, Au, Pt und Pd können mit Vanadium(II)-sulfatlösung aus ihren Verbindungen in elementarer Form gefällt und gravimetrisch bestimmt werden.
Part II: Z. analyt. Chem.189, 406 (1962). 相似文献
366.
R. S. Saxena C. P. Sharma M. L. Mittal 《Monatshefte für Chemie / Chemical Monthly》1967,98(6):2257-2262
Zusammenfassung Es wurde die Bildung und Zusammensetzung der durch Reaktion von Quecksilbernitrat mit Alkalipyrovanadat erhaltenen Quecksilber(II)-pyrovanadate mit Hilfe elektrometrischer Methoden, besonders der EMK-, der pH-metrischen und der Leitfähigkeitstitration untersucht. Die erhaltenen scharfen Knicke und Inflexionen in den Titrationskurven beweisen zwingend die Bildung von zwei Verbindungen, nämlich 1,5 HgO·0,5 Na2O·V2O5 und 2 HgO·V2O5 im pH-Bereich 7,0–8,0 bzw. 4,20–5,50.
Mit 3 Abbildungen 相似文献
The formation and composition of Hg(II)-pyrovanadate obtained by the interaction of Hg(NO3)2 and alkali pyrovanadate has been investigated by means of electrometric techniques involving emf, pH-metric and conductometric titrations. The well defined breaks and inflections obtained in titration curves provide cogent evidence for the formation of two compounds viz. 1.5 HgO·0.5 Na2O·V2O5 and 2 HgO·V2O5 in the pH ranges 7.0–8.0 and 4.20–5.50 respectively.
Mit 3 Abbildungen 相似文献
367.
Uncatalyzed and catalyzed oscillatory behavior in the redox potential in the oxidation of hematoxylin with acidic (H2SO4) bromate is reported.
- (H2SO4) .相似文献
368.
Thermally responsive poly(N-isopropylacrylamide) (PNIPAAM) brushes were grafted from polystyrene particles synthesized with surfactant free emulsion polymerization and functionalized with a thin shell of ATRP initiator on the surface. The ATRP initiator was present in the shell either alone or along with copolymerized styrene and also a crosslinker. The grafted brushes were characterized with transmission electron microscopy before and after negative staining with uranyl acetate. Cryo-scanning electron microscopy confirmed the growth of extremely long PNIPAAM layers from the surface, which otherwise looked shrunken in the transmission electron microscope owing to dehydration and possibly the effect of staining agent. The amount of grafted polymer also increases proportionally to the increase of the monomer concentration in the initial reaction system. The change in character from hydrophilic to hydrophobic with temperature and salt was found to be reversible and fast. The adsorption of protein complexes (tobacco mosaic virus) could be readily achieved at higher temperatures indicating the potential of the grafted particles to be used as stationary phases in temperature regulated chromatographic separations. 相似文献
369.
The ultraviolet-visible absorption spectrum of C60(OH)18 in water showed an absorption band with λmax = 215 nm and other characteristic absorption bands of C60 are not observed. The singlet-singlet and triplet-triplet absorption bands are not observed in the 400–900 nm region. It
has low reactivity with eaq− and formed an absorption band with λmax = 580 nm. The hydroxyl radicals react with a bimolecular rate constant of 2.4×109 dm3 mol−1 s−1 and showed an absorption band at 540 nm. 相似文献
370.