Search results for "Sodium perchlorate"
showing 7 items of 7 documents
Hydrolysis of dioxouranium(VI): a calorimetric study in NaClaq and NaClO4aq, at 25°C
2004
Abstract We report the results of a calorimetric study on the hydrolysis of UO 2 2+ in different ionic media (NaClO 4 aq , NaCl aq ) at 25 °C. Experiments in NaCl were performed at different ionic strength, at I ≤1 mol l −1 . The species considered in both ionic media were UO 2 (OH) + , (UO 2 ) 2 (OH) 2 2+ and (UO 2 ) 3 (OH) 5 + , and in addition (UO 2 ) 3 (OH) 4 2+ and (UO 2 ) 3 (OH) 7 − in NaCl aq . The dependence on ionic strength of enthalpy changes in NaCl aq was expressed by the simple linear equation Δ H pq =Δ H ° pq + aI 1/2 ( a , empirical parameter). Comparison with literature findings is given and some recommended values are reported.
Electrochemistry of hydrotalcite-supported bis(2-mercapto-2,2-diphenyl-ethanoate) dioxomolybdate complexes.
1998
The redox properties of the hydrotalcite-intercalated bis(2-mercapto-2,2-diphenyl-ethanoate) dioxomolybdate(VI) complex are investigated by cyclic voltammetry by using modified carbon paste electrodes and clay-modified electrodes. The electrochemical data provide evidence that boundary-associated species involving the VI, V and IV oxidation states of molybdenum are responsible for the electroactivity.
Interactions of lysozyme with hydrophilic and hydrophobic polymethacrylate stationary phases in reversed phase chromatography (RPC)
1994
Two silicas, one with a mean pore diameter of 30 nm and the other non-porous, were coated with polymethacrylates of increasing hydrophobicity in the sequence: poly-2-hydroxyethylmethacrylate (P2HEMA)1 polyethylmethacrylate (PEMA) and poly-n-octylmethacrylate (POMA). Association constants, Kass, between lysozyme and the coated silicas were determined by means of frontal analysis, and the apparent heats of adsorption, delta Happ, by means of microcalorimetry. Using Kass and delta Happ the changes in the apparent free energy, delta Gapp, and in the apparent entropy, delta Sapp, were calculated at a concentration of lysozyme < 10 mumol/l. The association between the lysozyme and the coated sili…
Complex Formation of the Uranyl (UO22+) Ion with the Diethylene Triaminopentaacetate (DTPA) Ligand at 25 °C in 3 M Sodium Perchlorate
2011
The complex formation between the uranyl (UO22+) ion and the diethylene triaminopentaacetate ligand (DTPA) has been investigated at 25 °C, in a 3 M sodium perchlorate medium. The overall protonation constants βjH of the free ligand have been previously determined in this ionic medium: six protonated species (HjA), with j ranging from 1 to 6, together with the free anion A5− have been identified in the concentration range from (3·10−3 to 13·10−3) mol·kg−1. Four complex species, H2UO2A−, HUO2A2−, UO2A3−, and UO2AOH4−, have been identified in the total uranyl concentration range from (1.1·10−3 to 5.7·10−3) mol·kg−1, and their overall stability constants determined, keeping the metal to ligand …
Automated determination of clomipramine and its major metabolites in human and rat serum by high-performance liquid chromatography with on-line colum…
1998
A fully automated method including column-switching and isocratic high-performance liquid chromatography (HPLC) was developed for simultaneous determination of the tricyclic antidepressant clomipramine and its metabolites demethylclomipramine, 2-, 8-, and 10-hydroxyclomipramine, 2-, and 8-hydroxydemethylclomipramine and didemethylclomipramine in serum. After serum injection into the HPLC system and on-line sample clean-up on a clean-up column (Hypersil CN; 10 x 4.6 mm) by an eluent consisting of 35% acetonitrile and 65% deionized water, the chromatographic separation was performed on an analytical column (LiChrospher CN; 250 x 4.6 mm I.D.) by an eluent consisting of 38% acetonitrile and 62%…
Ion transport through polyelectrolyte multilayers under steady-state conditions
2004
Abstract The permeability of a self-assembled polyelectrolyte multilayer to small ions under the influence of an applied potential difference is studied as a function of the number of layers and the nature of the supporting electrolyte. The multilayer is described as a series of homogeneously charged membranes with alternating sign of their fixed charge. Ion transport is described on the basis of the diffusion equation and the assumption of (Donnan) electrochemical equilibrium at the boundaries between layers. The calculated steady-state current–voltage curves are found to be in good agreement with experimental linear sweep voltammograms (at low sweep rate). The permeability of polystyrenes…
Studien zum Vorgang der Wasserstoffübertragung 36 [1] Einfluß von Art und Struktur einiger Leitsalze auf die elektrochemische Spaltung von Diarylsulf…
1975
Tensammetrische Messungen bestatigen, das Tetraalkylammoniumsalze in Methanol mit steigender Kettenlange der Alkylreste und wachsender Konzentration zunehmend starker an der Quecksilberoberflache adsorbiert werden. Polarographie und Zyklovoltammetrie der Diarylsulfone 1–8 in Methanol lassen folgende Schlusse zu: 1 Unabhangig von der Alkylkettenlange der Tetraalkylammoniumsalze werden die Diarylsulfone 1–6 nach einem ECE-Mechanismus gespalten. Bei Verwendung von Alkalileitsalzen sind die genannten Sulfone polarographisch inaktiv. 2 Beim 4-Cyano-diphenylsulfon wird mit Tetramethylammoniumchlorid zyklovoltammetrisch keine Reversibilitat des ersten Elektronen ubergangs beobachtet, wohl aber mit…