Reactivity pattern governing oxidation of aquometal ions by neptunium(VII). Oxidation of silver(I) and cobalt(II) in aqueous perchloric acid media

1975 ◽  
Vol 14 (3) ◽  
pp. 550-555 ◽  
Author(s):  
Edward. Deutsch ◽  
J. C. Sullivan ◽  
Kay O. Watkins
Keyword(s):  
Perchloric Acid ◽  
Reactivity Pattern ◽  
Acid Media ◽  
Aqueous Perchloric Acid

Acid–base behaviour of the ferricyanide ion in perchloric acid media. Spectrophotometric and kinetic study

1990 ◽  
Vol 68 (2) ◽  
pp. 228-235 ◽  
Author(s):  
Pedro L. Domingo ◽  
Begoña García ◽  
José M. Leal
Keyword(s):  
Kinetic Study ◽  
Perchloric Acid ◽  
Decomposition Reaction ◽  
Acid Base ◽  
Acid Media ◽  
Protonation Equilibria ◽  
Aqueous Perchloric Acid ◽  
Protonated Species ◽  
Heterolytic Dissociation ◽  
Homolytic Dissociation

A wide study was carried out of the acid–base behaviour of ferricyanide ions in aqueous perchloric acid media in the range 0.1–11.5 M. This study shows that protonation and decomposition of the ferricyanide ions occur simultaneously. The three successive protonation equilibria were found in the acidity ranges 0.1–4.0, 3.5–8.5, and 7.0–11.5 M HClO4, respectively. A kinetic study was also made of the decomposition reaction at 60 °C. The kinetic data are explained by considering a reaction mechanism involving homolytic and heterolytic dissociation steps. The homolytic and heterolytic rate constants corresponding to each of the four protonated species were determined, along with the acid–base protonation constants, pK1 = −6.25 ± 0.10; pK2 = −3.23 ± 0.03; and pK3 = −0.60 ± 0.02. Keywords: acid–base behaviour, protonated species, decomposition, homolytic dissociation, heterolytic dissociation.

scholarly journals Formation of protoporphyrin from haemoglobin in vitro

1967 ◽  
Vol 105 (3) ◽  
pp. 1209-1217 ◽  
Author(s):  
R. L. Veech ◽  
G. A. Rogeness ◽  
H. Weil-Malherbe
Keyword(s):  
Red Blood Cells ◽  
Perchloric Acid ◽  
Blood Cells ◽  
Red Light ◽  
Reducing Agent ◽  
Sodium Sulphite ◽  
Oxidative Destruction ◽  
Acid Media ◽  
Aqueous Perchloric Acid

1. The formation of protoporphyrin from red blood cells or purified haemoglobin in aqueous perchloric acid media without the prior isolation of haemin is described. The reaction is carried out in the absence of oxygen and in red light. Even traces of oxygen inhibit the reaction by oxidative destruction of protoporphyrin and by the oxidation of haem to haematin. 2. Perchloric acid releases iron and protoporphyrin from haemoglobin at similar rates, but the amount of protoporphyrin in the filtrate varies with the solubility of protoporphyrin in the concentration of perchloric acid used. The yield of protoporphyrin may reach 50–60%. Less than 5μg. of haemoglobin/ml. can be detected by measuring the fluorescence of the porphyrin released. 3. A porphyrin other than protoporphyrin is obtained in small amounts. Its possible identity is discussed. 4. If sodium sulphite is present as a reducing agent the exclusion of oxygen is not required, but the porphyrin formed is more polar and more soluble in water than protoporphyrin. The presence of oxygen appears to be necessary for the formation of this polar porphyrin.

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