Determination of the formation constants of iron(III) and vanadium(V) with .beta.-isopropyltropolone using the extraction method

Highly Effective Extraction of Iron(III) with 4-Isopropyltropolone in Nonpolar Solvents Containing 3,5-Dichlorophenol as a Synergist

“…The H + concentration was calculated from the H + activity measured with a glass electrode and the activity coefficient of H + , which was estimated to be 1.74 from a pH measurement of a mixed solution of 0.010 M HCl and 0.990 M NaCl at I = 1.0 M. The obtained acid-dissociation constants are shown in Table 1. The determined pKHA value of 7.06 is very close to that reported by Dyrssen,7.04 at I = 0.1 M, 1 rather than 7.5 at I = 1 M by Menis et al 5 The partition coefficient (PHA) of Hipt between heptane and 1.0 M HCl solution can not be directly measured from the distribution experiment, because a part of Hipt was present as the protonated form of H2ipt + in the aqueous phase. Therefore, the partition coefficient was calculated from the distribution ratio experimentally obtained, log DHA,0 = 0.95, using the following relation,…”

“…The logarithmic values of Kex, β1, and β2 were 9.77 ± 0.08, 12.60 ± 0.16, and 23.11 ± 0.09, respectively. The extraction constant obtained in heptane was close to that reported in chloroform, log Kex = 9.9 at I = 1 M in the literature, 5 although the formation of dihydroxytropylium of Hipt was not considered at all. The formation constant, log β1, has also been reported to be 13.0 in the same literature, which is comparable with the present value.…”

“…4 Especially, in the extraction of metal ions with 4-isopropyltropolone, chloroform is entirely used in the extensive research of Dyrssen 1 and afterwards reported papers. [5][6][7] According to our study concerning the interaction between tris(acetylacetonato)cobalt(III) and various hydrogen-bond donors, 8 chloroform brings about specific solvation to the chelate by hydrogen bonding in addition to its moderate polarity.…”

Statistical and mathematical methods in analytical chemistry

“…Rosenthal and Jones (461), in this regard, have evaluated the errors in the linear extrapolation of titration curves, due to both random measurement error and to incomplete reaction (finite equilibrium constant). Methods for evaluating multiple formation constants, using nonlinear least squares, have been reported by Kankare (283) for Bi-Cl complexes and by Menis, McClellan, and Bright (382) for species involving vanadium and iron. A somewhat different application of curve fitting to equilibria appears in the paper by Hutchinson and Fletcher (249).…”

Tropolone-induced effects on the unfolded protein response pathway and apoptosis in multiple myeloma cells are dependent on iron

“…Tropolones have been shown to inhibit select metalloenzymes, including histone deacetylase (HDAC) 2 and 8, and may have activity as iron-chelating agents. [8][9][10][11][12][13].…”