Dissoziationskonstanten und Austauscherchromatographie chlorierter Phenole

Drahoňovský, J.; Vacek, Z

doi:10.1135/cccc19713431

Cited by 68 publications

(10 citation statements)

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“…The K ow and p K a specified for each test chemical in Table 1 were used in model calculations. Estimates for these parameters commonly vary by a factor of two or more (e.g., [17–20]), and such uncertainty needs to be recognized in judging model fit to data. The aqueous diffusion coefficient for each chemical was estimated by the equation of Wilke and Chang [21].…”

Section: Methodsmentioning

confidence: 99%

Uptake and elimination of ionizable organic chemicals at fish gills: II. Observed and predicted effects of pH, alkalinity, and chemical properties

Erickson

McKim

Lien

et al. 2006

Enviro Toxic and Chemistry

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Effects of exposure-water pH on chemical uptake at rainbow trout (Oncorhynchus mykiss) gills were investigated for nine weakly acidic, chlorinated phenols with different ionization constants and hydrophobicities and for a moderately hydrophobic, nonionizable reference chemical (1,2,4-trichlorobenzene). Uptake rates for all chemicals varied little from pH 6.3 to 8.4, despite ionization of the chlorinated phenols ranging from less than 1 to greater than 99.9% among these pH values and chemicals. At pH 9.2, uptake rates were reduced substantially for the chlorinated phenols but not for the reference chemical. These results indicate greater bioavailability of neutral chemical forms but also considerable bioavailability of ionized forms that varies with pH. Three mechanisms were evaluated regarding such ionized chemical bioavailability. First, reduced pH at the gill surface causes net conversion of ionized molecules to more readily absorbed neutral molecules. This mechanism was tested by increasing exposure-water alkalinity, which increased gill surface pH and reduced uptake of the chlorinated phenols but not of the reference chemical. Magnitudes of these effects were close to predictions from a mathematical model for chemical exchange at fish gills that incorporated this mechanism. Second, ionized molecules contribute to uptake by maintaining high gradients of neutral molecules across epithelial membrane barriers, even if the barriers are impermeable to these ions. This mechanism was demonstrated to explain the similarity of uptake among pH values and chemicals at pH less than 8.4 and the degree to which uptake declined at pH 9.2. Third, membrane barriers can have some permeability to the ionized forms, but this was not important for the chemicals and conditions of the present study. Increased exposure-water pH also was demonstrated to increase elimination rates of these chemicals, which also was in accord with model expectations.

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Section: Methodsmentioning

confidence: 99%

Uptake and elimination of ionizable organic chemicals at fish gills: II. Observed and predicted effects of pH, alkalinity, and chemical properties

Erickson

McKim

Lien

et al. 2006

Enviro Toxic and Chemistry

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“…Figure 5 shows the correlation between the formation constants (log K1) and pKa of the chlorinated phenols. The latter were taken from the literature 13,14 (8.97 for 3-CP, 8.25 for 3,5-DCP, 7.71 for 2,3-DCP, 6.43 for 2,3,5-TCP, 7.85 for CNP) and can be considered to be a measure of the hydrogen-bond donor ability of the phenols. 15,16 All of these phenols are grouped into two main classes on the basis of the substituent at the 2 positions: (1) 3-CP, 3,5-DCP, and CNP; (2) 2,3-DCP and 2,3,5-TCP; each of which are located at different regions in Fig.…”

Section: Determination Of Formation Constantsmentioning

confidence: 99%

Thermodynamic Study of the Hydrogen-Bonding Ability of Tris(pentane-2,4-dionato)cobalt(III) and Tris(8-quinolinolato)-cobalt(III) with Chlorinated Phenols as Proton Donor

Khan

Imura

2000

ANAL. SCI.

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The hydrogen-bonding ability of metal chelates plays an important role in their solution behavior, such as solubility and liquid-liquid partition. In coordinately saturated chelates, especially tris(pentane-2,4-dionato)metal(III), specific solvation with chloroform, methanol, and water has long been studied by using various techniques, such as the solubility, X-ray analysis, IR, and NMR spectroscopy, and has been ascribed to outersphere coordination, principally via hydrogen bonding between the chelate and the solvent molecules. 1 Recently, one of the present authors demonstrated by the liquid-liquid partition technique that tris(pentane-2,4-dionato)cobalt(III) forms stable hydrogen-bonded complexes with chlorinated phenols, which are much stronger proton donors than the solvent molecules stated above.2 The partition coefficient of the cobalt(III) chelate remarkably increased owing to the formation of hydrogenbonded complexes. This finding led us to a new synergistic extraction system for aluminium(III), 3 scandium(III), 4 iron(III), 5 gallium(III), 6 and indium(III) 6 with pentane-2,4-dione (Hacac) and 3,5-dichlorophenol. In another work, Katsuta and Suzuki have reported on the extraction of iron(III) with 8-quinolinol in the presence of various chlorinated phenols as the synergist.

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“…Effect of Pluronic L61 on the PO CL Reaction Quantum Yield Chemiluminescence of bis(pentachlorophenyl) oxalate BPCPO is highly reactive towards hydrogen peroxide (рК а of pentachlorophenol is 4.74 [41]). Addition of hydrogen peroxide buffer solution to a concentrated solution of BPCPO and HP IX in acetonitrile triggers the chemiluminescent reaction (Fig.…”

Section: Resultsmentioning

confidence: 99%

Micelles of amphiphilic copolymers as a medium for peroxyoxalate chemiluminescent reaction in water environment

Romanyuk

Melik‐Nubarov

2015

Polym. Sci. Ser. B

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The peroxyoxalate chemiluminescent reaction of bis(4 nitrophenyl) oxalate or bis(pentachlo rophenyl) oxalate with hydrogen peroxide in the presence of hematoporhyrin IX water insoluble derivative in micelles or associates of Pluronics F68, L64, L61 and the alternating copolymer dimethyl siloxane ethyl ene oxide is investigated. Pluronic L61, which forms large clusters in solution, has the greatest impact on the reaction quantum yield. The micelles influence on the efficiency of the reaction with bis(pentachlorophenyl) oxalate is stronger in comparison to that with bis(4 nitrophenyl) oxalate. The chemiluminescence quantum yield increases with the concentrations of fluorophore and hydrogen peroxide. If the polymer content is being varied, quantum yield passes through the maximum, which corresponds to the largest amount of particles containing both oxalate and porphyrin.

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Dissoziationskonstanten und Austauscherchromatographie chlorierter Phenole

Cited by 68 publications

References 0 publications

Uptake and elimination of ionizable organic chemicals at fish gills: II. Observed and predicted effects of pH, alkalinity, and chemical properties

Uptake and elimination of ionizable organic chemicals at fish gills: II. Observed and predicted effects of pH, alkalinity, and chemical properties

Thermodynamic Study of the Hydrogen-Bonding Ability of Tris(pentane-2,4-dionato)cobalt(III) and Tris(8-quinolinolato)-cobalt(III) with Chlorinated Phenols as Proton Donor

Micelles of amphiphilic copolymers as a medium for peroxyoxalate chemiluminescent reaction in water environment

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