Extraction of cobalt(II) and nickel(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HPMBP) and tri-n-octylamine (TOA)

The extraction of Co(II) with mixtures of 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one ((H)PMBP) and tri-n-octylamine (TOA) is investigated in order to explore the influence of diluents and inorganic anions with synergistic acidic extractant + liquid anion exchanger systems. Although it is proved that the same species [HTOA]⁺ [Co(PMBP)₃]^? is extracted from various inorganic media, with toluene as the diluent, the presence of ClO₄^? SO₄^2? or Cl^? anion modifies the distribution of the anions which are associated to (HTOA)⁺ in the organic phase, leading to different synergistic equilibria; with Cl^? or SO₄^2?: $\text{CO(PMBP)}{}_2$ + $\text{(HTOA}{}^{\mathrm{+}}$,PMBP^?) ?$\text{(HTOA}{}^{\mathrm{+}}$,Co(PMBP)₃^? (log K = 6.10) and with ClO₄^? : $\text{Co(PMBP)}{}_2$ + $\text{HPMBP}$ + $\text{(HTOA}{}^{\mathrm{+}}$,ClO₄^? ? $\text{(HTOA}{}^{\mathrm{+}}$,Co(PMBP)₃^? + H⁺ + ClO₄^? (log K = 2.34) The same synergistic equilibrium is observed for the extraction of Ni(II) from ClO₄^? medium, with a comparable value of the constant (log K = 2.45). The synergistic effect is cancelled in n-octanol.     

Extraction of indium(III) from chloride medium with 1-phenyl-3-methyl-4-acylpyrazol-5-ones. Synergic effect with high molecular weight ammonium salts.

The extraction of In(III) from 1M (Na,H)(Cl,ClO₄) media with 4-acylpyrazol-5-ones (HL) in toluene at 25°C is described by equilibria In ³⁺ + 3 $\text{HL}$ ? $\text{InL}{}_3$ + 3 H⁺ (log K = 1.48, 1.03, 0.87 with acyl = benzoyl, lauroyl, 2-thenoyl), InCl ²⁺ + 2 $\text{HL}$ ? $\text{InClL}{}_2$ + 2 H⁺ (log K = 0.26, ?0.45, ?0.35 respectively) and In³⁺ + m Cl^? ? InCl_m^(3-m)+ (log β_m available from literature). The extraction from 1M (Na,H)(Cl,NO₃) medium is enhanced by addition of aliquat (TOMA⁺,Cl^?) and the following synergic equilibrium takes place : $\text{InCl}{}_2$ + $\text{(TOMA}{}^{\mathrm{+}}$,Cl^?) ? $\text{(TOMA}{}^{\mathrm{+}}$, InCl₂L₂^? (log K = 5.49, 5.25, 5.21 respectively). Cl^? of (TOMA⁺,Cl^?) is exchanged by NO₃^? with the equilibrium constant log K = 1.50. If (TOMA⁺,Cl^?) is replaced by tri-n-octylammonium chloride, the synergic effect is largely reduced (log K = 4.17 with acyl = benzoyl). The extraction from chloride solutions containing ClO₄^? remains unchanged by addition of ammonium salts.     

Excess volumes and isentropic compressibilities for (2-ethoxyethanol + n-heptane) at 298.15 K

Excess volumes and ultrasonic speeds have been measured for (2-ethoxyethanol + n-heptane) at 298.15 K. Isentropic compressibilities, excess isentropic compressibilities, and the partial molar excess quantities $\text{K}{}_{\mathrm{<mtext>S,\; </mtext><mtext>i</mtext>}}{}^{\mathrm{<mtext>E</mtext>}}\text{= ?(}\text{?V}{}_{\mathrm{i}}{}^{\mathrm{E}}\text{?p}\text{)}{}_{\mathrm{S}}$ were calculated from the results. The excess volume is positive over the entire mole-fraction range, whereas the curves for the excess isentropic compressibility is sigmoid with negative values occurring at mole fractions of 2-ethoxyethanol greater than 0.35. A qualitatitive interpretation of the results is presented.     

A dynamic nuclear magnetic resonance study of 1,3-intramolecular shifts in pentacarbonyl-chromium(O) and -tungsten(O) complexes of β-2,4,6-trimethyl-1,3,5-trithian, 1,3,5-trithian, 1,3-dithian and 2-methyl-1,3-dithian: the x-ray crystal structure of [W(CO)5{SCH(Me)SCH(Me)SCH(Me)}]

Variable temperature ¹H NMR spectroscopy has been used in the study of 1,3-intramolecular shifts of the M(CO)₅ moiety in complexes of the general formula [M(CO)₅L], (M = Cr or w), L = $\text{SCH}{}_2\text{SCH}{}_2\text{SC}$H₂, $\text{SCH}{}_2\text{SCH}{}_2\text{CH}{}_2\text{C}$H₂ and $\text{SCH(Me)SCH}{}_2\text{CH}{}_2\text{C}$H₂. For the 1,3,5-trithian complexes precise energy barriers for the process have been obtained by detailed computer simulation of the static and dynamic spectra. Our results suggest that the magnitude of ΔG^≠ (298.15 K) for the 1,3-shift is largely dependent upon the skeletal flexibility of the ligand system. In this context we have investigated the X-ray crystal structure of the highly substituted trithian complex [W(CO)₅{β-$\text{SCH(Me)SCH(Me)SC}$H(Me)}].     

Anionic polymerization of styrene in tetrahydrofuran (THF) with cumylcaesium as initiator

The kinetics of the anionic polymerization of styrene initiated by cumylcaesium have been reinvestigated in tetrahydrofuran. Quite unlike earlier investigations, the ion pair rate constant $\text{k}{}_{\mathrm{p}}\text{(±)}$ was found to be 130 l/mole/sec at 25° and the dissociation constant of polystyrylcaesium to be about 5 × 10^?10 mole/l. In the presence of caesiumtriphenylcyanoborate used as a common ion salt addition, $\text{k}{}_{\mathrm{p}}\text{(±)}$ was measured over a wide range of temperature. The results are compared to the temperature behaviour of the ion pair rate constants obtained with polystyrylsodium in polar solvents; they indicate that the existence of solvent separated ion pairs cannot be excluded for polystyrylcaesium.     

Energy transfer between Gd3+ and Sm3+ the effect of Gd3+ on quenching of Sm3+ and intensity parameters of Sm3+ in borate glasses

Intensity parameters of Sm³⁺ in borate glasses were obtained by fitting the oscillator strengths to the Judd-Ofelt formula and a study of energy transfer from gadolinium to samarium was performed. An increase of samarium fluorescence originating from the ${}^4\text{G}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ level was observed in the presence of gadolinium, in the concentration range of 0.1–3 wt% samarium with gadolinium constant at 3 wt%. The intensity of samarium fluorescence on excitation at 273 nm increased by one order of magnitude in the presence of gadolinium. From the excitation spectrum of the double-doped glasses (Gd + Sm), it was deduced that energy absorbed by gadolinium is transferred from ${}^6\text{P}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ gadolinium levels to the ${}^4\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ and ${}^4\text{P}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ samarium levels.The mechanism of this energy transfer was obtained by plotting the energy transfer probabilities as a function of samarium concentration. A linear dependence of $\text{η}{}_0\text{η}$ (η intensity of gadolinium in the presence of samarium) versus square of concentration of Sm + Gd is obtained. From this it is concluded that the transfer is of electric-multipolar type, mainly dipole-dipole. A small increase (about 10%) of fluorescence of samarium in the presence of gadolinium excited at levels where no energy transfer can take place is attributed to the fact that the quenching of samarium occurring by the cross relaxation $\text{(}{}^4\text{G}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{→}{}^6\text{F}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{) (}{}^6\text{H}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{→}{}^6\text{F}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}$ is suppressed by the presence of gadolinium as seen from concentration dependence of samarium doped glasses compared to double-doped glasses.     

Potentiometric gas sensors for ammonia based on ion-selective electrodes for silver (1), copper (11) and mercury-(11).

Potentiometric gas sensors sensitive to ammonia were prepared with ionselective electrodes for silver(I), copper(II) or mercury(II). These electrodes measure the degree of the complexation between the metal ions and ammonia. Ammonia concentrations above 10^-3.5M can be measured by these sensors. The response to changes in ammonia concentrations is rapid. The Ag⁺- and Cu²⁺-based sensors gave a response of approximately $\text{100 mV}\text{log[NH}{}_3\text{]}$ while the Hg²⁺-based sensor gave a $\text{60 mV}\text{log [NH}{}_3\text{]}$ response.     

Bifunctional initiators—I. Synthesis and characterization of 4,4′-azobis(4-cyanovaleryl)bisbenzoyl and bisacetyl diperoxides

The paper refers to the synthesis and properties of some bifunctional initiators, viz. 4.4′-azo-bis(4-cyanovaleryl)bisbenzoyl diperoxide (I) and 4,4′-azobis(4-cyanovaleryl)bisacetyl diperoxide (II), obtained from the acid chloride of cyanovaleric acid and condensed with perbenzoic acid or peracetic acid. The structures of the products were established by i.r. and NMR spectroscopy, as well as by elemental analysis. Kinetic studies on the thermolyses of the two initiators led to the following results: for I. $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{azo, 360°K = 129 min}$, $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{peroxy, 360°K = 245 min}\text{, E}{}_{\mathrm{<mtext>azo</mtext>}}\text{=}\text{174.2 kJ/mol}\text{, E}{}_{\mathrm{<mtext>peroxy</mtext>}}\text{=}\text{206.5 kJ/mol}$; for II, $\text{t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{azo, 357°K = 152 min}\text{, t}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{peroxy, 357°K = 208 min}\text{, E}{}_{\mathrm{<mtext>azo</mtext>}}\text{=}\text{155.4 kJ/mol}\text{, E}{}_{\mathrm{<mtext>peroxy</mtext>}}\text{=}\text{188.5 kJ/mol}$.     

The reorientation of Cd2+-vacancy and Pb2+-vacancy complexes in KCl

The relaxation of Pb²⁺-vacancy and Cd²⁺-vacancy dipoles in purified KCl crystals was studied using a double crystal dc polarization method which self-corrects relaxation effects due to spurious causes. In the radius range from Cd²⁺ to Ba²⁺ these results and most others support Dreyfus' model. The reciprocal relaxation times for each impurity are given by

$\text{τ}{}^{\mathrm{?1}}{}_{\mathrm{<mtext>Cd</mtext>}}\text{=2.06x10}{}^{12}\text{exp(?s0.64±0.01}\text{eV}\text{)}\text{kT}$

;

$\text{τ}{}^{\mathrm{?1}}{}_{\mathrm{<mtext>Pb</mtext>}}\text{=1.19x10}{}^{13}\text{exp(?0.69±0.01}\text{eV}\text{)}\text{kT}$

.It is also shown that the presence of H₂O or its products greatly perturb the relaxation times observed.     

Zur Kinetik der Spinellbildung von β-Ga2O3 mit zweiwertigen Oxiden II. Tracerdiffusion von 63Ni2+ und 67Ga3+ im Nickel-Gallium-Spinell

The self-diffusion coefficients of ⁶³Ni²⁺ and ⁶⁷Ga³⁺ have been measured in nickel-gallium spinels of the general formula $\text{Ni}{}_{\mathrm{1?y}}\text{Ga}{}_{\mathrm{<mtext>2+</mtext><mtext>2y</mtext><mtext>3</mtext>}}\text{O}{}_4$ between 1653 and 1838 K using the restactivity method. Thin radioactive oxide layers are produced on inactive sample surfaces by sedimentation from aqueous solution. The sample composition corresponds to the solubility limit of NiO, respectively, β-Ga₂O₃ in the spinel lattice.It has been concluded that diffusion of Ni²⁺-and Ga³⁺-ions occurs via vacant cation sites.The values obtained for the two cations, which are in the same order of magnitude, are used to calculate the rational reaction constants for NiGa₂O₄ formation after Schmalzried.There is a satisfying agreement between these reaction constants and those values determined by thickness measurement of spinel reaction layers; the agreement between values of activation energy is very good.It is suggested that NiGa₂O₄ formation proceeds after the Wagner mechanism of counterdiffusion of cations.     

Nd3+, Eu3+, and Gd3+ ions as local probes in the NaxSr3−2xLnx(PO4)2 and KCaLn(PO4)2 rare earth phosphates

Use of Nd³⁺, Eu³⁺, and Gd³⁺ as local structural probes allows the determination of the rare earth positions in the Na_xSr_3?2xLn_x(PO₄)₂ (Ln = La to Tb) and KCaLn(PO₄)₂ phases (Ln = rare earth). Moreover, a common feature of both series is a particularly high splitting of the excitation ${}^6\text{P}{}_{\mathrm{<mtext>7</mtext><mtext>2</mtext>}}$ and ${}^6\text{P}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$ levels of the Gd³⁺ ions.     

Excess molar enthalpies of {(1 − x2 − x3)Al + x2Bi + x3Ga}(I) alloys

The excess molar enthalpies H_m^E{(1 ? x₂ ? x₃)Al + x₂Bi + x₃Ga}(I) have been measured between 725 and 1170 K along the sections $\text{(1 ? x}{}_2\text{? x}{}_3\text{)}\text{x}{}_3\text{=}\text{1}\text{3}$, 1, and 3, and $\text{x}{}_2\text{x}{}_3\text{=}\text{1}\text{3}$, 1, and 3, with a high-temperature Calvet calorimeter using both the direct- and indirect-drop methods of mixing; experimental uncertainty is quoted respectively at 6.7 per cent and 9.9 per cent. The equilibrium temperatures confirmed phase boundaries previously determined by potentiometry, d.t.a., and calculation. Extrapolation of the experimental excess molar enthalpies to the limiting binary alloys {(1 ? x₂)Al + x₂Bi} allows new values for the excess molar enthalpies of these alloys to be proposed. The excess molar enthalpies of the ternary liquid mixtures can be represented correctly using these new values and Bonnier's equation.     

Synthesis and solution properties of poly(ditoluyl itaconates)

The three o-, m- and p- isomers of ditoluyl itaconate were obtained by esterification of cresols and itaconic acid in the presence of diphosphorous pentoxide, and then polymerized in bulk with AlBN as initiator. The polymers were investigated in dilute solution, including $\text{M}{}_{\mathrm{W}}$ determination and precipitation fractionations, and the results compared with those for poly(diphenyl itaconate). The presence and position of -CH, in the aromatic ring influence the initial rates of polymerization, polymer solubilities in organic solvents and $\text{[η]/}\text{M}{}_{\mathrm{W}}$ relations. Unperturbed dimensions, obtained by extrapolating to τ-conditions, vary slightly with the -CH, group position, due to steric and probably other effects.     

Peroxo salts as initiators of vinyl polymerization—2. Kinetics of polymerization of acrylic acid and sodium-acrylate by peroxodisulphate in aqueous solution—effect of pH and Ag+ catalysis

Results on the rate of polymerization of acrylic acid by S₂O^2?₈ ion in alkaline and acid conditions are presented. R_p depended upon $\text{[S}{}_2\text{O}{}^{\mathrm{2?}}{}_8\text{]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and $\text{[monomer]}{}^{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ both in acid and alkaline solutions. The influence of ionic strength, the effect of pH on R_p and the catalytic effect of Ag⁺ and Cu²⁺ on the system have been discussed. Suitable mechanisms are proposed.     

Kinetics and mechanism of the interaction of hexaaquochromium(III) with octacyanomolybdate(IV) ions

The kinetics of the interaction of hexaaquochromium(III) ion with potassium octacyanomolybdate(IV) have been studied using conductance and spectrophotometric data. The mechanism of the reaction is discussed and the effect of H⁺ ion and the ionic strength on the rate of the reaction determined. The reaction is found to be pseudo-first order with respect to potassium octacyanomolybdate(IV) and inverse first order with [H₃O⁺]. The rate of the reaction increases with increase in ionic strength and temperature. Activation parameters have been calculated using the Arrhenius equation and have the values ΔE^* = 1.3 × 10² kJ mol^?1, ΔH^* = 129 kJ mol^?1, ΔS^* = ?315 e.u., ΔF^* = 2.3 × 10² kJ and A = 1.5 × 10^?3. The mechanism proposed is based on ion-pair formation and the rate equation obtained is given by: k_obs=$\text{[}{}_{\mathrm{kK}}{}_{\mathrm{<mtext>E</mtext>}}\text{[H}{}_3\text{O}{}^{\mathrm{+}}\text{]+}\text{k′K′k}{}_{\mathrm{E}}\text{k}{}_{\mathrm{h}}\text{][Mo(CN)}{}_8{}^{\mathrm{4?}}\text{]}\text{[H}{}_3\text{O}{}^{\mathrm{+}}\text{]+}\text{k}{}_{\mathrm{<mtext>h</mtext>}}\text{+[}\text{K}{}_{\mathrm{<mtext>E</mtext>}}\text{[H}{}_3\text{O}{}^{\mathrm{+}}\text{]+}\text{K′}{}_{\mathrm{E}}\text{k}{}_{\mathrm{h}}\text{][Mo(CN)}{}_8{}^{\mathrm{4?}}\text{]}$     

Kaempferol (3,5,7,4′-tetrahydroxyflavone) as a chromogenic reagent for tin(IV)

Kaempferol forms a yellow colored chelate with tin(IV) in 0.1 to 0.01 N HCl medium. Based on this reaction a sensitive spectrophotometric method for determination of micro amounts of tin(IV) has been developed. The sensitivity of the color reaction 0.0029 μg of $\text{Sn/cm}{}^2\text{}\text{log}\text{I}{}_0\text{I}\text{= 0.001}$, at 430 nm in 0.1 N HCl medium and Beer's law is obeyed up to 3.6 ppm of tin. Several complexing anions do not interfere and they have been used for masking some of the cations which interfere in the determination.     

The vapor-pressure isotope effect for (CH3)2CO and (CD3)2CO from 206 to 333 K

Isotopic vapor-pressure differences between (CH₃)₂CO and (CD₃)₂CO have been measured by differential capacitance manometry. When combined with available absolute vapor pressures for (CH₃)₂CO the results may be expressed (206 to 333 K) as:

$\text{1n}\text{(}\text{p}{}_{\mathrm{H}}\text{p}{}_{\mathrm{D}}\text{) = 3642.6(K/T)}{}^2\text{? 22.205(K/T) + 0.01129}$

     

Spectroscopic properties of Nd3+ ion in TbAlO3 single crystals

Growth of terbium aluminate single crystals and investigation of Nd³⁺ ion spectroscopic properties in them are described. Detailed investigation of absorption and luminescence spectra of Nd³⁺ ions in TbAlO₃ at T = 77 and 300°K permits obtainment of a complete diagram of the Stark components energy. The spectral-structural regularities of Nd³⁺ ions in orthoaluminate monocrystals are analyzed. The dependence on interionic distance of the position of the center of gravity of the ground terms of Nd³⁺ ion along with the nephelauxetic shift of ${}^4\text{F}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ term of Nd³⁺ ion is investigated.     

Perfluorocycloalkyl(aryl) diazenes from heptafluoronitrosocyclobutane and nonafluoronitrosocyclopentane

The perfluoronitrosocycloalkanes, heptafluoronitrosocyclobutane and nonafluoronitrosocyclopentane, are convenient precursors to a family of new perfluorocycloalkyl(aryl) diazenes. With aniline and o-aminobenzamide, $\text{CF}{}_2\text{(CF}{}_2\text{)}{}_{\mathrm{x}}\text{C}$FNN$\text{C(CH)}{}_4\text{C}$H and $\text{CF}{}_2\text{(CF}{}_2\text{)}{}_{\mathrm{x}}\text{C}$FNN$\text{C(CH)}{}_4\text{C}$C(O)NH₂ (x = 2,3) are formed. Additionally, heptafluoronitrosocyclobutane gives $\text{CF}{}_2\text{(CF}{}_2\text{)}{}_2\text{C}$FNN$\text{CCFCFCHCFC}$F and $\text{CF}{}_2\text{(CF}{}_2\text{)}{}_2\text{C}$FNN$\text{C(CH)}{}_4\text{C}$NH₂ with 2,3,5,6-tetrafluoroaniline and o-phenylenediamine