摘要:

AbstractThe complexing of Cu(II) by polyacrylic acid has been investigated. Potentiometric measurements have been employed to facilitate the experimental program. The stability constant of CuA2, the dominant species observed, has been determined to be approximately 6.5 × 103, a value in good agreement with the formation constant of 4.25 × 103reported for Cu(acetate)2. The quantitative evaluation of this stability constant is made possible by (1) correcting for complication arising from the large and variable electric field at the surface of the polyelectrolyte in the polymer domain and by (2) expressing the concentration of polymer species in terms of the polymer domain volum

ISSN:0021-2148    

DOI:10.1002/ijch.197300057

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe kinetics of the reaction between Ni2+and pyrophosphate have been investigated over a wider range of conditions than previously. At 25°, a variation of the ionic strength between 0.02 and 0.20 M (achieved by adding potassium nitrate at appropriate concentrations) showed that the salt effect, though acting on the formation constant of an ion pair rather than on the rate constant of the rate‐determining step, is essentially “classical”. By varying the pH between 4.5 and 7.0, at least two parallel reaction paths were observed, involving Ni2+and the ions HP2O3−7and H2P2O2−7. The latter path has a rate constant that is ∼28 times smaller than that of the former and makes an appreciable contribution to the observed rate only at the two lowest pH values. Possible reasons for this difference in reactivity are discussed. The rate constant for the path involving HP2O3−7was 1.61 × 106M−1s−1at 25°, I = 0.1 M. The activation parameters for this path are ΔH≠= 18.8 Kcal mole−1and ΔS≠= 33 e.u. All kinetic experiments were carried out by the T‐jump method. The equilibrium constants necessary for the evaluation of the results were determin

ISSN:0021-2148    

DOI:10.1002/ijch.197300058

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThe induction periods of calcium oxalate precipitation at high supersaturations were measured and the degrees of inhibition in the presence of different trace quantities of polyphosphates were determined. Crystals were grown from uninhibited and from partially inhibited solutions. The presence of both polyphosphates and of cationic impurities affects the crystal habit very strongly: rod‐like crystals up to 3 mm in length grew from inhibited solutions in a week, whereas very small round particles of 10−2mm size sprang from the uninhibited solutions. Some previously published mechanisms are reviewed, and a new, comprehensive, heterogeneous nucleation mechanism of growth is proposed to explain the simultaneous inhibition of precipitation and inducement to growth of large cryst

ISSN:0021-2148    

DOI:10.1002/ijch.197300059

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractWhen alcohol solutions of copper salts are mixed with pyridine‐2‐aldehyde (PyA) and aliphatic diamines (A) (either ethylene diamine or 1,3‐propane diamine) at pH ≤ 6.5, a copper complex containing a molecule of the pyridine derivative and a molecule of the diamine is formed, or a complex containing an additional molecule of the pyridine aldehyde is formed, depending on the PyA concentration in the solution. When the molar concentrations are Cu2+: 2PyA: A, and the pH ≥ 10, the copper (II) ion is reduced to monovalent copper, and a Schiff base of the copper complex is formed. When alcoholic solutions of copper, 2‐acetylpyridine (AcPy), and aliphatic diamines are mixed in concentration ratios of Cu2+: 2AcPy: A, and pH>9.5, again, the copper ion is reduced and a Schiff base is obtained. At pH = 7.5 a triple complex is obtained only from the copper chloride, containing either or one or two molecules of acetylpyridine, depending on the concentration of the latter in t

ISSN:0021-2148    

DOI:10.1002/ijch.197300060

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractHigh purity alumina is prepared from local ores, containing about 35% alumina, and from low‐grade, 20%, HCl solution. Iron impurities are removed by solvent extraction, and upon pyrolysis, high grade 60% HCl gas is collected. The amorphous alumina obtained at 350°C is transformed to “transition alumina” at 600°C with an increase in surface area; subsequently at 1000–1100°C, high purity crystalline corundum is obtained. The transition‐ and amorphous alumina seem to have promising qualities for desiccant and c

ISSN:0021-2148    

DOI:10.1002/ijch.197300061

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractAmmonium chloride can be separated into its constituents, ammonia and hydrochloric acid, by treating it with a metal oxide. Whereas earlier it was shown that this separation is feasible for 14 different metals, when effected in two steps attwo different temperatures, we now show thatisothermal operationis possible, with the driving force consisting of concentration differences of NH4Cl and water vapor, respectively. The experiments with Fe2O3, MgO, NiO and PbO showed that the volatility of FeCl3interferes when Fe2O3is used, but the other oxides, which do not have volatile chlorides, serve well at temperatures of about 300°C

ISSN:0021-2148    

DOI:10.1002/ijch.197300062

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractUV spectra of acetylacetone dioxime (2,4‐pentanedione dioxime = AADO), benzoylacetone dioxime (BADO) andbis‐benzoylacetone dioximato‐Cu(II) [Cu‐ (BADO*)2; BADO* = oxidized BADO] are recorded for aqueous and CHCl3solutions at different pH values and interpreted. pKavalues (1st dissociation constant) for AADO and BADO at constant ionic strenths (μ= 0.12) are derived: pKa(AADO) = 10.50; pKa(BADO) = 9.50, and the influence of molecular structure on acid‐base properties is discussed. Diagrams of possible molecular orbital energy‐level transitions for the oxime and the nitroso chromophores are given. The marked influence of acids (HC1) and bases (triethylamine, TEA) on the shape of the UV spectra of Cu‐ (BADO*)2is discussed and explained in terms of the acid‐base properties of the nitroso and the oxime groups. Additional evidence has been adduced for the presence of nitroso group and of hydrogen bonds in

ISSN:0021-2148    

DOI:10.1002/ijch.197300063

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractThis is a review of a small part of the work on photodissociation with polarized light performed by Kent Wilson and his students [1–4] at the University of California at San Diego and the author and his students [5–7]at Columbia. The physics of the experiment has been presented in a recent review by R.N. Zare [8] who was the first to suggest the utility of such work. We comment on the photodissociation of three molecules — I2,Cd(CH3), andα‐iodonap

ISSN:0021-2148    

DOI:10.1002/ijch.197300064

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractGroup II A atoms Ca, Sr and Ba form dihalide molecules some of which are linear and others bent. Two general models are considered to account for this. In the first we suppose a purely ionic structure in which the atoms are polarized by the resulting internal electric field. The polarization energy varies with valence angle; but it is shown that if this model were the correct one, all these molecules should be linear. In the second model we consider the valence states that arise from excitations s2→ sp and s2→ sd. The first of these would lead to a linear molecule, the second to a bent one. Considerations of the energies of excitation to these two valence states together with a similar situation for the positive ions show that bent molecules are favored when the central atom is heavy and when the attached halogens are as electronegative as possible. The experimental results are thus completely explai

ISSN:0021-2148    

DOI:10.1002/ijch.197300065

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY

摘要:

AbstractBoundary conditions and quantum mechanical numerical methods for evaluating transition probabilities of photodissociation and half‐collisional processes are presented. Direct and indirect dissociation modes are discussed. In each case we write a set of equations tying the particular boundary behaviour of each dissociation mode to the standard scattering boundary conditions. Numerical schemes based on these equations are presented. The case of competing dissociation reactions and exchange is also considered for the indirect case. When interference between these modes is expected to play a significant role, we show how the quantum jump due to photon and electron impact can be incorporated into the set of equations describing the dissociation. Finally we indicate how a numerical construction of potential surfaces from photofragment spectra and absorption spectra in the continuous and predissociation range can be obtained using these numerical scheme

ISSN:0021-2148    

DOI:10.1002/ijch.197300066

出版商:WILEY‐VCH Verlag    

年代:1973

数据来源: WILEY