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1.
Hydrogen bonding between water and tributyl phosphate (TBP) in TBP? CCl4? H2O system has been studied by 1H NMR. A new model and an empirical equation have been established on the basis of Li's model and the parameters of hydrogen bond between water and TBP are determined by nonlinear optimization method. In TBP? CCl4? H2O system change of 1H chemical shift of water can be satisfactorily explained by the new model and the empirical equation in the whole concentration range. When the concentration of water in the organic phase is very low, the main existing forms of water are H2O · TBP and H2O · 2TBP. When the concentration of water reaches saturation, the main existing form is associated water, but there are still about 20% of water existing in the forms of H2O · TBP and H2O · 2TBP. 相似文献
2.
The mathematical model of H2O-HNO3-UO2(NO3)2-TBP-dodecane system has been elaborated. Mole fractions and volume ones and rational activity coefficients have been used in order to create the system of equations on the base of mass action law. Method for calculating activity coefficients was provided. The formation constants of uranyl nitrate di-solvate and mono-solvate and di-solvate of acid have been determined. Interaction between uranyl nitrate di-solvate and dodecane and between TBP and dodecane was taken into account. Activity coefficients of nitric acid and uranyl nitrate in mixed solutions were considered. Errors of adequacy have been determined for the systems containing 30% and 12% TBP concentrations. 相似文献
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4.
《Fluid Phase Equilibria》2005,238(2):180-185
Data on the solubility of manganese sulphate monohydrate in water, and in aqueous alcohols is essential for salting-out crystallization studies. The solubilities for the quaternary system MnSO4·H2O + MgSO4·7H2O + H2O + MeOH solution were determined in the temperature ranges 293.2–308.2 K over the mole fraction methanol ranges of 0.00–0.16. The solubility data were used for modelling with the modified extended electrolyte non-random two-liquid (NRTL) equation. The present extension uses ion-specific parameters instead of the electrolyte-specific NRTL binary interaction parameters. This approach has feasibility for many electrolytes and mixed aqueous solution systems principally. The model was found to correlate the solubility data satisfactory. 相似文献
5.
Viscosities, densities, and water activities for binary and ternary systems of poly(propylene glycol) 425 + H2O and poly(propylene glycol) 425 + MgSO4 + H2O have been measured at 25°C. From density and viscosity measurements, excess volumes and excess viscosities of the binary poly(propylene glycol) 425 + H2O, over the entire composition range, were obtained and correlated by means of a Redlich–Kister type equation. Viscosity, density. and water activity data for ternary system of poly(propylene glycol) 425 + MgSO4 + H2O were correlated by using a semiempirical equation. 相似文献
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《Journal of Inorganic and Nuclear Chemistry》1978,40(10):1787-1791
Tritium tracer techniques have been used to measure the solubility of water in undiluted TBP from 0 to 65°C at unit water activity and as a function of water activity at 25°C; from the latter results, the activity of the solvent has been derived by applying the Gibbs-Duhem relation. The solubility measurements were extended to include TBP-n-octane solutions that were 0.01-1.0 M in TBP, and these values were used to estimate hydration quotients.The solubility of water in undiluted TBP is 3.57 ± 0.02 M at 25°C and decreases slowly with increasing temperature. At constant temperature, the water content decreases rapidly at first and then more slowly with decreasing water activity. The variation of the activity of TBP in the diluent-free water system suggests that the extracted species is TBP·H2O, when the loading of TBP is less than 0.5 mole H2O per mole of TBP. Results of computer analyses of the solution data can be interpreted in terms of monomeric anhydrous TBP and the formation of the monohydrate TBP·H2O, and suggest the additional hydrate species (TBP·H2O)2, (TBP·H2O)4, and TBP·2H2O, with formation concentration quotients log QTH = −0.82, log Q(TH)2 = 1.82, log Q(TH)4 = −0.39, log QTH2 = −1.66. 相似文献
8.
Andrzej Leś 《Theoretical chemistry accounts》1985,66(6):375-393
Intermolecular potential energy curves for the hydrogen bonded systems H2O·H2S, H2O·H2Se and H2S·H2S were calculated with nonempirical pseudopotentials using optimized-in-molecules basis sets augmented by polarization functions. The H2O·H2O interaction energy curve has been also considered as a test case. The present results for H2O·H2S and H2S·H2S indicate much weaker intermolecular interactions than those found in previous ab initio calculations. The H2O·H2Se interaction was found to be quite similar to H2O·H2S.This work was partly supported by the Polish Academy of Sciences within the Project PAN-09, 7.1.1.1On leave from Quantum Chemistry Laboratory, Dept. of Chemistry, University of Warsaw, Pasteura 1, 02-093. Warsaw, Poland 相似文献
9.
Enhanced adsorption of radioactive strontium ions from aqueous solution by H2O2-modified attapulgite
Effective adsorption of Sr(II) onto H2O2-modified attapulgite in aqueous solution was investigated about kinetics and isothermal equilibrium adsorption. The adsorption equilibrium process of Sr(II) on adsorbents reached about 8 h at 40 °C. The adsorption kinetics followed the pseudo-second order equation and the isothermal adsorption data were fit well with the Langmuir isotherm model. The enhanced adsorption mechanism of H2O2-modified attapulgite for Sr(II) in aqueous solution was expatiated in detail. The H2O2 treatment for attapulgite is effective and as-made adsorbents can be applied for removal of Sr(II) in radioactive waste water.
相似文献10.
Pavel Ya. Tishchenko Alexander S. Bychkov Andrea Hrabéczy-Páll Klára Tóth Ernö Pungor 《Journal of solution chemistry》1992,21(3):261-274
The mean activity coefficients of NaCl in the system NaCl+Na2SO4+H2O at various compositions were determined in the temperature range 5–45°C from the emf of potentiometric cells. By processing the results using Pitzer's equations the mixing parameters describing the non-ideal behavior of electrolytes were calculated. The temperature coefficients of the mixing parameters were determined and found not to be significant. The mixing parameters and temperature coefficients calculated for the binary mixture can be used to describe the behavior of multicomponent systems containing NaCl and Na2SO4, and eventually sea water. 相似文献
11.
Atomic resonance absorption spectroscopy (ARAS) was applied to measure S atoms, behind shock waves in COS/H2 pyrolysis or CS2/H2 photolysis systems. Both the pyrolysis of COS and the photolysis CS2 was used to generate the S atoms, which subsequently reacts with H2 via the reaction: The photolysis experiments were designed to provide clear first-order conditions for reaction (R3); i.e., the H2 concentration exceeds that of S by at least a factor of 100. The S atom profiles obtained during pyrolysis of highly diluted COS/H2/Ar mixtures were analyzed by computer simulations based on a simplified reaction mechanism using the rate coefficient k3 as a fitting parameter. Both groups of experiments covered the temperature range of 1257 K ? T ? 3137 K and lead to a rate coefficient of: . © 1995 John Wiley & Sons, Inc. 相似文献
12.
The extraction of radium into a mixture of 2-thenoyltrifluoroacetone (HTTA) and tributyl phosphate (TBP) or trioctylphosphine oxide (TOPO) in n-hexane or cyclohexane has been investigated with regard to the dependence on pH, and TBP and TOPO concentrations. It has been found that the formation of mixed complexes of the type Ra(TTA)2 (TBP)2 and Ra(TTA)2(TOPO)2 occurs and the overall extraction constants of both complexes were calculated. With the systems described, very high distribution ratios of radium have been attained; these may advantageously be used for the separation and concentration of traces of radium. 相似文献
13.
The solvent extraction behavior of [TcCl6]2− in the HCl-TBP system was studied together with that of its aqua complexes. It was deduced from the dependence of the distribution
coefficient of [TcCl6]2− both on the HCl and TBP concentrations that a possible form extracted into TBP is H2[TcCl6](TBP)4. The distribution coefficients of aqua complexes of [TcCl6]2− were found to be in the order of [TcCl4(H2O)2]<[TcCl6]2−<[TcCl5(H2O)]−. 相似文献
14.
A new method for the synthesis of α-bromoketones was suggested. The C5-C11 linear and branched ketones in the reaction with the systems H2O2-LiBr-CeIII and H2O2-LiBr-CeIV in acetonitrile were brominated at α-position. The reaction is highly selective. 相似文献
15.
R. Ghiasi 《Russian Chemical Bulletin》2012,61(2):248-252
A density functional theory at the B3LYP/6-311G(d,p) level was applied to investigate the impact of hydrogen and water molecules on borthiin. The calculated binding energies of complexes were corrected for the basis set superposition error. The changes in structural parameters and in chemical hardness values were calculated for borthiin interacting with H2 and H2O. The strength of the weak interaction between borthiin and the H2 and H2O molecules was analyzed using the topological properties according to the ??Atoms in Molecules?? theory by Bader. The factors influencing the strength of the interaction between the borthiin and the H2 and H2O molecules were considered in detail using the NBO analysis. The vibrational frequencies and the intensities of the B-H stretching bands were calculated. The nucleus independent chemical shift (NICS) method was used to study the aromaticity of borthiin and the complexes. 相似文献
16.
The tri-n-butyl phosphate-nitric acid (TBP-HNO3) complex prepared by contacting the pure TBP with the concentrated HNO3 can be used for direct dissolution of lanthanide and actinide oxides in the supercritical fluid carbon dioxide (SCF-CO2). Properties of the TBP-HNO3 complex have been studied. Experimental results showed that when the initial HNO3/TBP volume ratio was varied from 1 : 7 to 5 : 1, the concentration of HNO3 in the TBP-HNO3 complex changed from 1.95 to 5.89 mol/L, the [HNO3]/[TBP] ratio of the TBP-HNO3 complex changed from 0.61 to 2.22, and the content of H20 in the TBP-HNO3 complex changed from 2.02% to 4.19%. All of the density, viscosity and surface tension of the TBP-HNO3 complex changed with the concentration of HNO3 in the complex, and were higher than those of the pure TBE The protons of HNO3 and H2O in the complex underwent rapid exchange to exhibit a singlet resonance peak in nuclear magnetic resonance spectra. When the TBP-HNO3 complex was dissolved in a low dielectric constant solvent, small droplets of HNO3 were formed that can be detected by NMR. 相似文献
17.
A. V. Ochkin D. Yu. Gladilov S. Yu. Nekhaevskii 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(10):1800-1801
This paper presents a model of the formation of hydrated and solvated ionic pair, nonhydrated monosolvate HNO3 · TBP (tri-n-butylphosphate), hydrated disolvate HNO3 · 2TBP, and semisolvate 2HNO3 · TBP, to which an unlimited number of HNO3 molecules can be added. The equilibrium was calculated using mole fractions. To calculate the mole fraction of free (not
bonded to solvates) water, we suggested an equation containing four parameters, three of which are determined from the data
for the independent TBP-H2O-diluent system. 相似文献
18.
Theophylline hydrogels of atactic‐poly(vinyl alcohol) (a‐PVA)/H2O and a‐PVA/NaCl/H2O systems were prepared followed by cyclic freezing (?30°C for 16 hr)–thawing (at room temperature for 8 hr) and one cycle gelation (at ?20°C for 24 hr) processes, respectively. In order to prepare xerogels (dried hydrogels) of these hydogel systems, an apparently first‐order mass transfer phenomenon of water as evaporation was observed for a‐PVA/H2O hydrogel system, while heating at 60°C. The rate of evaporation decreased with increasing time in hyperbolic fashion. The total surface area (both lateral and two end surfaces of hydrogel matrix disc) decreased linearly for the first 90 min and thereafter had a tendency towards the steady‐state. The total mass flux showed time dependent linear reduction phenomenon, which is a characteristic physical behavior for these hydrogel systems on heat treatment. When NaCl was included in a‐PVA/H2O system mass transfer of water followed fourth‐order polynomial. But in consideration of a comparative study, sustained mass transfer was found from the hydrogel matrices of a‐PVA/H2O/NaCl system (gelation at ?20°C). Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
19.
The high-temperature reaction between sulfur dioxide and acetylene in an excess of argon was studied in a 1?in. i.d. single-pulse shock tube. Mixtures ranging from 1.81% to 5.40% SO2 and 1.60% to 4.90% C2H2 were heated to reflected shock temperatures of 1550°–2150°K, for dwell times of about 0.6 msec and gas dynamically quenched. Total reaction densities were 0.89 to 5.4 × 10?2 moles/1. The reaction products were analyzed by gas chromatography. A technique was developed for separating Ar, C2H4, C2H2, SO2, CO, CO2, H2S, COS, and CS2. The major products of the reaction are CO, H2, CS2, and sulfur. The products observed were compared with those predicted on the assumption that equilibrium was attained. Several preliminary experiments were carried out with ethylene-sulfur dioxide mixtures, and the results indicated that for this combination the sulfur dioxide probably reacted with the acetylene generated from the decomposition of the ethylene, rather than directly with the ethylene. The rate of decline in the sulfur dioxide content in C2H2-SO2 mixtures was found to be approximately second order (total) and can be empirically represented by A mechanism is proposed to account for the overall reaction kinetics. 相似文献
20.
Triclinic single crystals of [(C6H10)(NH3)2][Ni(H2O)4C6H2(COO)4]·4H2O have been prepared in aqueous solution at 55 °C. Space group (Nr. 2), a = 691.23(6), b = 924.84(5), c = 1082.43(7) pm, α = 74.208(6)°, β = 75.558(7)°, γ = 68.251(6)°, V = 0.60985(7) nm3, Z = 1. The Nickel(II) species, located on a crystallographic inversion centre, is coordinated in a trans‐octahedral fashion by two oxygen atoms stemming from the centrosymmetric pyromellitate anions and four from water molecules (Ni–O 205.82(12) – 208.11(13) pm). The connection between Ni2+ and [C6H2(COO)4)]4? leads to infinite chain‐like polyanions extending parallel to with {Ni(H2O)4[C6H2(COO)4]2?}n composition. [(C6H10)(NH3)2]2+‐cations are accomodated between the chains, compensating for the negative charge of the polyanions. Thermogravimetric analysis in air showed that the loss of water of crystallisation occurs in two steps between 102 and 206 °C, corresponding to the loss of 6 and 2 water molecules per formula unit, respectively. The dehydrated sample was stable between 206 and 353 °C. Further decomposition yielded nickel(II) oxide (NiO). 相似文献