Protonation constants of ?-alanine in electrolyte mixtures at constant ionic strength

1995 ◽  
Vol 24 (10) ◽  
pp. 1049-1058 ◽  
Author(s):  
I. Brandariz ◽  
S. Fiol ◽  
M. Sastre de Vicente
2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Piotr Seliger ◽  
Danuta Tomczyk ◽  
Grzegorz Andrijewski ◽  
Ewa Tomal

The protonation constants of new group of peptidomimetic cyclophanes with valine or phenylalanine moieties incorporated into the macrocyclic skeleton as well as their linear analogues were determined by potentiometric measurements in solutions of methanol-water mixtures at 25°C and constant ionic strength. The influence of cavity size, location of protonation sites, and attached substituents of the macrocyclic ligands on the protonation constants were discussed on the basis of potentiometric measurement as well as H1-NMR results.


1988 ◽  
Vol 85 ◽  
pp. 523-527
Author(s):  
M.M. Zuleika ◽  
Palhares SILVA ◽  
Ernesto Rafael GONZALEZ ◽  
Luis Alberto AVACA ◽  
Artur de Jesus MOTHEO

1992 ◽  
Vol 57 (7) ◽  
pp. 1451-1458 ◽  
Author(s):  
Refat M. Hassan

The kinetics of oxidation of arsenic(III) by hexachloroiridate(IV) at lower acid concentrations and at constant ionic strength of 1.0 mol dm-3 have been investigated spectrophotometrically. A first-order reaction in [IrCl62-] and fractional order with respect to arsenic(III) have been observed. A kinetic evidence for the formation of an intermediate complex between the hydrolyzed arsenic(III) species and the oxidant was presented. The results showed that decreasing the [H+] is accompanied by an appreciable acceleration of the rate of oxidation. The activation parameters have been evaluated and a mechanism consistent with the kinetic results was suggested.


2004 ◽  
Vol 49 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Francesco Crea ◽  
Concetta De Stefano ◽  
Ottavia Giuffrè ◽  
Silvio Sammartano

2009 ◽  
Vol 97 (7) ◽  
Author(s):  
Claire Le Naour ◽  
M. V. Di Giandomenico ◽  
Y. Zhao ◽  
M. Mendes

AbstractSolvent extraction in the conditions of tracer scale chemistry was used to study protactinium(V) complexation with sulphate, chloride, oxalate and diethylene-triamine-pentaacetate. Extraction experiments were conducted using the chelating agent thenoyltrifluoroacetone (TTA) in toluene at constant ionic strength and temperature. Information on the species involved in partition equilibria relative to protactinium(V) complexation were deduced from a systematic study of the variations of distribution coefficient of Pa(V) as function of ligands, protons and TTA concentration.


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