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1.
Lyudmila V. Chernykh Jitka Eysseltova Mikhail Y. Skripkin 《Monatshefte für Chemie / Chemical Monthly》2003,124(1):751-761
Solubility isotherms in the CuBr2−MBr−H2O (M
+ = Li+, Na+, Cs+) systems at 298.15 K were measured. The results together with other available literature data for copper chloride and bromide
systems were treated by hydration analysis, and comparative discussion of ionic processes taking place in the respective saturated
solutions was performed. 相似文献
2.
Ruthenium (III) trichlorid solid crystals have been mechanically attached to gold surfaces and studied by cyclic electrochemical
quartz crystal microbalance measurements in the presence of aqueous solutions of different concentrations containing M+Cl−, where M+=H+, Li+, Na+, K+, Rb+, Cs+. The RuCl3 and the complexes formed during the electrochemical transformations show two or more reduction and reoxidation pairs of waves,
depending on the experimental conditions (concentration, scan rate, and potential range). The voltammetric peaks are shifted
into the direction of higher potentials with increasing electrolyte concentrations except at very high concentrations when
the peaks belong to the first reduction/reoxidation processes move oppositely. The mass change was reversible, during reduction
mass increase, while during oxidation mass decrease occurred at medium electrolyte concentrations in two, more or less distinct
steps. At high or low concentrations the mass excursions are more complex involving different mass increase/decrease regions
as a function of potential which vary with the potential range of the measurements. The peak potentials and the electrochemical
activity strongly depend on the nature of the cations and pH. It is related to the formation of complexes in different compositions.
The mass change decreases with increasing electrolyte concentrations attesting the important role of the water activity and
the transport of solvent molecules. It was concluded that in dilute solutions during the first reduction step M+ ions enter the surface layer. The strongly hydrated Li+ ions transfer water molecules into the microcrystals, while simultaneously with the incorporation of K+, Rb+, and Cs+ ions H2O molecules leave the surface layer. The opposite transport of ions and solvent molecules occur during oxidation. In the course
of further reduction the incorporation of all ions studied except that of Cs+ ions is accompanied with water sorption. The number of sorbed water molecules is proportional to the hydration number of
these ions. A reaction scheme is proposed in which M+
m-3[RuIIICl
m
(H2O)
n
]3-m
· xH2O (m≥3) and [RuIIICl
m
(H2O)
n
]3-m
(Cl−)3-m
· xH2O (m≤3) type complexes are reduced to the respective – or depending on the electrolyte concentration higher or lower – Ru(II)chloro
complexes resulting in mixed valence compounds (phases). Taking into account the layered structure of RuCl3 the electrochemical reduction can be explained as an intercalation reaction in that mixed valence intercalation phases with
a general formula M
x
+(H2O)
y
[RuCl3]
x− are formed from RuCl3·x H2O. The reduction/reoxidation waves are related to the redox transformations of Ru(III) to Ru(II) sites, while the composition
of the polynuclear complexes and the structure of microcrystals change.
Presented at the 4th Baltic Conference on Electrochemistry, Greifswald, March 13.−16., 2005. 相似文献
3.
Surface active micelle formable surfactant-Cr(III) complexes of the type cis-α-[Cr(trien)(C16H33NH2)X]2+ (where trien = triethylenetetramine; X = F−, Cl−, Br−) have been studied in n-alcohol and in formamide at different temperatures by conductance measurements. Standard Gibbs energy changes (ΔG
o
mic), enthalpies (ΔH
o
mic) and entropies (ΔS
o
mic) of micelle formation have been determined by studying the variation of the Critical Micelle Concentration (CMC) with temperature.
Critical micelle concentrations have also been measured as a function of percentage concentration of alcohol added. It is
suggested that alcohol addition leads to an increase in formamide penetration into the micellar interface that depends on
the alcohol chain length. The results are discussed in terms of an increased hydrophobic effect, dielectric constant of the
medium, the chain length of the alcohols and the surfactant in the solvent mixture. 相似文献
4.
I. V. Baklanova V. N. Krasil’nikov L. A. Perelyaeva O. I. Gyrdasova 《Theoretical and Experimental Chemistry》2011,47(4):215-218
lid solutions Ti1−x
M
x
O2−x/2 in the anatase and rutile forms were obtained from the precursors Ti1−x
M
x
(OCH2CH2O)2−x/2 at T = 450–900 °C. The temperature and concentration dependence of the phase transformation of anatase to rutile in Ti1−x
M
x
O2−x/2 was investigated by Raman spectroscopy. It was shown that the anatase phase is stabilized most effectively by the Eu3+ dopant. 相似文献
5.
Lyudmila V. Chernykh Jitka Eysseltova Mikhail Y. Skripkin 《Monatshefte für Chemie / Chemical Monthly》2003,134(5):751-761
Summary. Solubility isotherms in the CuBr2−MBr−H2O (M
+ = Li+, Na+, Cs+) systems at 298.15 K were measured. The results together with other available literature data for copper chloride and bromide
systems were treated by hydration analysis, and comparative discussion of ionic processes taking place in the respective saturated
solutions was performed.
Corresponding author. E-mail: jitka@prfdec.natur.cuni.cz
Received August 6, 2002; accepted (revised) November 29, 2002
Published online April 3, 2003 相似文献
6.
D. Attwood 《Colloid and polymer science》1969,235(1):1193-1195
Summary Measurements of the electrophoretic mobilities of the micelles of the anionic detergent C16H33(OCH2 · CH2)7OSO3Na have been made in aqueous sodium chloride solutions over the concentration range 0-0.01 M and used to calculate the magnitude
of the electroviscous effect and the micellar charge in these solutions. The micellar hydration, as assessed from viscosity
data, is shown to decrease as the salt concentration is increased and this is thought to be a consequence of the lower micellar
charge in the more concentrated salt solutions which allows a greater contraction of the ethylene oxide chains resulting in
a loss of water mechanically trapped by the micelles. 相似文献
7.
S. Akcay S. Tulumen S. Oymak H. I. Kaya 《Journal of Radioanalytical and Nuclear Chemistry》2007,273(3):603-608
The complex formation of curium(III) with L2-aminobutyric acid was characterized by time-resolved laser-induced fluorescence
spectroscopy (TRLFS) at trace Cm(III) concentrations (3·10−7 M). The various curium(III) species, MpHqLr, identified are characterized by their individual luminescence spectra and luminescence lifetimes. The following formation
constants were determined log β101 = 5.17±0.07, log β102 = 9.00±0.07, and log β103 = 11.30±0.09 at ionic strength I = 0.5M. Possible structures of the curium aminobutyrate species will be discussed on the basis of the luminescence lifetime
measurements and the magnitude of the formation constants. 相似文献
8.
Abstract
Tridentate Schiff base ligands L1 and L2, derived from the condensation of 2-hydroxy-3-methoxybenzaldehyde (L) with 2-aminoethanol or 2-aminobutan-1-ol, react with nickel chloride, azide, or thiocyanate to give rise to two dinuclear complexes of formulas [Ni2(L)(L1)2N3]·H2O (1), [Ni2(L2)3(μ1,1-N3)]·2H2O (2), and one tretranuclear complex [Ni2(L2)2(NCS)]2(C2H5OH)2 (3), where L1 = HOCH2CH(C2H5)NCHC6H3(O−)(OCH3) and L2 = HO(CH2)2NCHC6H3(O−)(OCH3). We have characterized these complexes by analytical, crystal structures, and variable temperature magnetic susceptibility measurements. The magnetic properties of the complexes are studied by magnetic susceptibility (χM) vs. temperature measurements. The χM T vs. T plots reveal that compounds 1, 2 and 3 are ferromagnetically coupled. 相似文献9.
The association of an anionic dye C.I. Reactive Orange 16 (RO16) and different types of surfactants, i.e., anionic surfactant
sodium dodecylsulfate, nonionic surfactants poly(oxyethylene) ethers (C
m
POE10, m = 12, 16, and 18; C12POE
n
, n = 4, 10, and 23), was investigated using tensiometry in a certain micellar concentration range. RO16 was shown to aggregate
in water when its concentration is above the threshold value. The surface tension lowering and critical micellar concentration
(CMC) values were interpreted on the same grounds as those for surfactants mixtures. The tensiometric measurements of dye-surfactant
systems are carried out as a function of the molar concentration of solution at 25°C. Using Rubingh’s regular solution theory,
the values of interaction parameters were found to be negative for all studied binary mixtures. These negative values indicate
that there is an attractive interaction of the surfactants in mixed micelles and reflect synergistic behavior of a mixture.
In all studied systems, deviations from ideal behavior were observed depending on the type of surfactant. Interaction parameters
calculated using regular solution theory are changed from −2.62 to −12.43. The smallest deviation from ideal behavior is obtained
for the RO16-C12POE4 mixed system; i.e., in the case when nonionic surfactant has the shortest alkyl chain and the smallest number of ethylene
oxide units.
The text was submitted by the authors in English. 相似文献
10.
A. R. Mustafina Yu. G. Elistratova V. V. Syakaev R. R. Amirov A. I. Konovalova 《Russian Chemical Bulletin》2006,55(8):1419-1424
Concentration range of solubilization of calix[4]resorcinarene (H8L) in sodium dodecyl sulfate (SDS) micelles was found. The interaction of the deprotonated form of H8L (tetraanions [H4L]4−) with tetramethylammonium (TMA) and choline cations in micellar solutions of SDS was studied by pH-metry and NMR spectroscopy.
The concentration dependences of the change in the cloud point in a multicomponent system TMA (choline)-[H4L]4-SDS-tetrabutylammonium bromide were determined. A correlation of these dependences with host-guest binding processes was
found. The sharp change in the cloud points of the corresponding micellar solutions in concentration regions of TMA (0-5·10−4 mol L−1) and choline (0–1.1· 10−3 mol L−1) is caused by the formation of inclusion complexes TMA (choline)-[H4L]4− at the interface of the aqueous and micellar pseudophases.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 8, pp. 1366–1371, August, 2006. 相似文献
11.
R. F. Balabaeva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(7):1288-1290
Using the experimental values ΔH
Hexc and ΔS
Hexc (ΔH
Nexc and ΔS
Nexc) for solid solutions of hydrogen and nitrogen in molybdenum, we calculate the parameters ɛHMand ɛNM of interaction between hydrogen (nitrogen) and molybdenum lattice doped with small additives of transition metals M; the
values of the activity coefficients on hydrogen and nitrogen γHM and γNM, ΔH
H, ΔH
N, ΔS
H, ΔS
N; enthalpy (ηHM and ηNM) and entropy (σHM and σNM) parameters of interaction over the 1100–1300 K range for alloys of Mo1 − y
M
y
H
x
and Mo1 − y
M
y
N
x
types (y = 0.01 and 0.02; x = 0.01 and 0.02). 相似文献
12.
N. Kumaraguru K. Santhakumar S. Kalyanasundharam 《Journal of solution chemistry》2011,40(10):1673-1686
The critical micelle concentration (CMC) of surfactant–Cr(III)–dodecylamine complexes of the type cis-α-[Cr(trien)(C12H25NH2)X]2+ (where trien = triethylenetetramine; X = F−, Cl−, Br−) has been studied in n-alcohol and in formamide at different temperatures, by electrical conductivity measurements. From the CMC values as a function
of temperature, various thermodynamic properties have been evaluated: standard Gibbs energy changes (Δmic
G
0), standard enthalpy changes (Δmic
H
0) and standard entropy changes (Δmic
S
0) for micellization. Critical micelle concentrations have also been measured as a function of the percentage composition of
alcohol added. The solvent composition dependences of these thermodynamic parameters were determined. It is suggested that
alcohol addition leads to an increase in formamide penetration into the micellar interface that depends on the alcohol’s chain
length. The results are discussed in terms of an increased hydrophobic effect, dielectric constant of the medium, the chain
length of the alcohols, and the surfactant in the solvent mixture. 相似文献
13.
Wincel H 《Journal of the American Society for Mass Spectrometry》2011,22(9):1570-1576
The thermochemical properties ΔH
o
n
, ΔS
o
n
, and ΔG
o
n
for the hydration of sodiated and potassiated monosaccharides (Ara = arabinose, Xyl = xylose, Rib = ribose, Glc = glucose,
and Gal = galactose) have been experimentally studied in the gas phase at 10 mbar by equilibria measurements using an electrospray
high-pressure mass spectrometer equipped with a pulsed ion beam reaction chamber. The hydration enthalpies for sodiated complexes
were found to be between −46.4 and −57.7 kJ/mol for the first, and −42.7 and −52.3 kJ/mol for the second water molecule. For
potassiated complexes, the water binding enthalpies were similar for all studied systems and varied between −48.5 and −52.7
kJ/mol. The thermochemical values for each system correspond to a mixture of the α and β anomeric forms of monosaccharide
structures involved in their cationized complexes. 相似文献
14.
O. P. Charkin 《Russian Journal of Inorganic Chemistry》2011,56(11):1775-1781
The equilibrium geometric parameters and energetic and spectroscopic characteristics of low-lying conformers for several series
of model cage-substituted (mixed) borane, alane, and gallane closo-dianions M
i
M′12 − i
H122−(M, M′ = B, Al, Ga), as well as of “bare” gallium-aluminum anions Ga
i
Al12−i
− with i = 0–12, were calculated within the B3LYP approximation of the density functional theory using 6–31G* and 6–311+G** basis
sets. Differences in structure and stability between alanoborane clusters of similar composition are revealed. In clusters
where the M and M’ heteroatoms are close in size and electronegativity (in gallonoalanes and gallium-aluminum anions), successive
substitutions of M′ for M are accompanied by small energy changes and occur quasi-stochastically in different positions of
the cage. When the substituents are significantly different (in alanoboranes), mixed clusters are unstable against disproportionation
into homonuclear “predecessors” M12H122− and M′12H122−, and the most favorable M
i
M′12 − i
H122− structures among them are those in which M
i
M′12 − i
the cages are subdivided into homonuclear “subclusters” M
i
and M′t′12−i
with a maximal number of homonuclear bonds (M-M and M′-M′) and a minimal number of heteronuclear bonds (M-M′). 相似文献
15.
K. N. Semenenko V. V. Burnasheva N. A. Yakovleva E. A. Ganich 《Russian Chemical Bulletin》1998,47(2):209-212
The experimental data on the mechanism of hydride dispersion of intermetallic compounds of the LaNi5 type and the crystal structures of hydride phases based on these compounds were analyzed. A new approach was suggested and
substantiated, which allows one to consider hydride dispersion as a result of a redox process associated with the formation
of Hδ− hydride ions at concentrations of hydrogen in the solid hydrideC
H>-C
H
cr. The value ofC
H
cr is determined by the redox potential of the reaction Hδ++Mδ−⇌Hδ′−+Mδ′+.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 2, pp. 214–217, February, 1998. 相似文献
16.
Electrochromic hydrated Ni-oxide films were prepared using a dip-coating technique from a nickel sulphate heptahydrate precursor
in combination with glycerol, formamide and polyvinyalcohol. In-situ monochromatic (λ=400 nm) spectroelectrochemical measurements
using a potential of −0.4 V to 0.8 V in 0.1M LiOH electrolyte revealed that the electrochromic efficiency was 23.5 cm2/C. The observed colouring/bleaching transmittance of a 100 nm thick film changed during potential cycling (20 cycles) by
45%. Ex-situ FT-IR absorption/reflection measurements performed at near-grazing incidence angle conditions (80°) confirmed
transformation of as-deposited α-Ni(OH)2 phase to β-Ni(OH)2 at cathodic (bleached state) and β-NiOOH at anodic (coloured state) potentials during extended cycling (200 cycles). Clear
evidence of the OH− ions insertion and release of SO
4
2−
ions from the as-deposited films when soaked (0.5 hour) in 0.1M LiOH are given. These processes are accompanied by the transformation of the residual COO− groups originating from the peptisation with glacial acetic acid into CO
3
2−
species residing in the films during extensive potential cycling. 相似文献
17.
Ashraf A. Mohamed 《Monatshefte für Chemie / Chemical Monthly》2001,132(8):919-928
Summary. A new selective, sensitive, and simple kinetic method is developed for the determination of trace amounts of iodide. The
method is based on the catalytic effect of iodide on the reaction of triflupromazine (TFP) with H2O2. The reaction is followed spectrophotometrically by tracing the oxidation product at 498 nm within 1 min after addition of
H2O2. The optimum reaction conditions are TFP (0.4 × 10−3
M), H2SO4 (1.0M), H3PO4 (2.0M), and H2O2 (1.6M) at 30°C. Following this procedure, iodide can be determined with a linear calibration graph up to 4.5 ng ċ cm−3 and a detection limit of 0.04 ng ċ cm−3, based on the 3 Sb criterion. The method can also be applied to the determination of iodate and periodate ions. Determination of as little as
0.2, 1.0, 2.0, and 4.0 ng ċ cm−3 of I−, IO3
-, or IO4
- in aqueous solutions gave an average recovery of 98% with relative standard deviations below 1.6% (n = 5). The method was applied to the determination of iodide in Nile river water and ground waters as well as in various food
samples after alkaline ashing treatment. The method is compared with other catalytic spectrophotometric procedures for iodide
determination.
Received January 19, 2001. Accepted (revised) March 12, 2001 相似文献
18.
I. I. Tverdokhlebova I. A. Ronova V. M. Men'shov N. V. Pertsova 《Russian Chemical Bulletin》1998,47(12):2348-2351
Molecular-weight parameters of new silane homo- and copolymers were analyzed. For all polymers, theM
w values are close ((6.0–8.6)·104), the curves of molecular weight distribution are unimodal, andM
w/M
n=2−2.5. Cyclic fragments or those containing the −C=C− groups make the major contribution to the polysilane chain rigidity.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2430–2433, December, 1998. 相似文献
19.
Ashraf A. Mohamed 《Monatshefte für Chemie / Chemical Monthly》2001,56(2):919-928
A new selective, sensitive, and simple kinetic method is developed for the determination of trace amounts of iodide. The method is based on the catalytic effect of iodide on the reaction of triflupromazine (TFP) with H2O2. The reaction is followed spectrophotometrically by tracing the oxidation product at 498 nm within 1 min after addition of H2O2. The optimum reaction conditions are TFP (0.4 × 10−3 M), H2SO4 (1.0M), H3PO4 (2.0M), and H2O2 (1.6M) at 30°C. Following this procedure, iodide can be determined with a linear calibration graph up to 4.5 ng ċ cm−3 and a detection limit of 0.04 ng ċ cm−3, based on the 3 Sb criterion. The method can also be applied to the determination of iodate and periodate ions. Determination of as little as 0.2, 1.0, 2.0, and 4.0 ng ċ cm−3 of I−, IO3 -, or IO4 - in aqueous solutions gave an average recovery of 98% with relative standard deviations below 1.6% (n = 5). The method was applied to the determination of iodide in Nile river water and ground waters as well as in various food samples after alkaline ashing treatment. The method is compared with other catalytic spectrophotometric procedures for iodide determination. 相似文献
20.
Precise conductance measurements are reported on dilute aqueous solutions of the sodium and potassium salts of orthophosphoric
acid at 25 ∘C. Conductance measurements on solutions of electrolytes such as these phosphate salts that exist in solution as complicated
mixtures of ions have previously proved difficult to interpret. To overcome this, a mathematical method has been developed
to calculate the concentrations of all the species in the aqueous system M3PO4/M2HPO4/M2HPO4/H3PO4 (M = Na or K) over a continuous range of stoichiometries. The Lee–Wheaton conductance equation has been used to interpret
the conductance of these multicomponent solutions in terms of the limiting ionic conductances and concentrations of all the
ions in the solution. The limiting molar conductances of the ions H2PO4
− and HPO4
2− and the ion-pair formation constants of these ions with sodium and potassium ions were determine
This work has enabled the accurate determination of solution parameters for the important hydrogenphosphate ions in water
and provides an excellent example of the use of an advanced conductance theory in the analysis of the conductance of multicomponent
electrolyte systems. 相似文献