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1.
F. Bousmina L. Zayani D. Ben Hassen-Chehimi N. Kbir-Ariguib M. Trabelsi-Ayedi 《Monatshefte für Chemie / Chemical Monthly》2003,134(5):763-768
Summary. The diagram of the ternary system Mg2+/Cl−, SO4
2−–H2O was established at 15°C by means of analytical and conductimetric measurements. Three compounds were found in this diagram,
which are MgSO4·6H2O, MgSO4·7H2O, and MgCl2·6H2O. The solubility field of MgSO4·7H2O is important whereas those of MgSO4·6H2O and MgCl2·6H2O are small. The compositions (mass-%) of the two invariant points determined by the two methods are: MgSO4:MgCl2=2.73:33.80 and MgSO4: MgCl2=3.38:28.91. Both the measured and the calculated isotherm at 15°C have been used for modelling of the diagram Mg2+/Cl−, SO4
2−–H2O between 0 and 35°C. The polythermal invariant point was approximately located between 15 and 10°C.
Corresponding author. E-mail: ariguib@planet.tn
Received October 16, 2002; accepted (revised) December 3, 2002
Published online April 24, 2003
RID="a"
ID="a" Dedicated to Prof. Dr. Heinz Gamsj?ger on the occasion of his 70th birthday 相似文献
2.
E. E. Karslyan D. S. Perekalin P. V. Petrovskii A. O. Borisova A. R. Kudinov 《Russian Chemical Bulletin》2009,58(3):585-588
The cation [CpRu(η6-C10H8)]+ was shown to exchange naphthalene for other arenes under visible-light irradiation to form the complexes [CpRu (η6-arene)]+ (arene = C6H6, 1,4-C6H4Me2, 1,3,5-C6H3Me3, or 1,2,4,5-C 6H2Me4) in 70–95% yields. The reaction rate of exchange decreases in the series arene = 1,4-C6H4Me2 > C6H6 > 1,3,5-C6H3Me3 > 1,2,4,5-C 6H2Me4 >> C6Me6 and increases with the coordinating ability of the solvent in the order CH2Cl2 < THF—CH2Cl2 mixture (1: 1) < acetone. 相似文献
3.
E. M. Glebov V. F. Plyusnin V. P. Grivin A. B. Venediktov S. V. Korenev 《Russian Chemical Bulletin》2007,56(12):2357-2363
Photochemistry of the PtBr6
2− complex in aqueous solution was studied by steady-state and laser flash photolysis (308 nm). The multistep photoaquation
of the complex occurs in the nano-and microsecond time intervals without the formation of intermediate platinum(III) complexes.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2277–2283, December, 2007. 相似文献
4.
Inspired by carbo-benzene and its inorganic analogues, in the current work, the viability of extended systems (called carbomers) formed from aromatic small rings was studied. The aluminum aromatic cluster, Al42?, and its isoelectronic carbon analogue, C42+, were employed as starting point. The insertion of alkynyl units into the Al–Al and C–C bonds results in the extended molecules named carbomers. These molecules were compared with the global minima structures, which were searched employing the genetic algorithm program, GEGA. The electronic delocalization (aromaticity) of the isomers was studied with the induced magnetic field (Bind). The results showed that global minimum of C122+ (formed from C42+) was an unexpected diatropic structure which presented a similar magnetic response to the C42+ cluster. Also, optical properties of C122+ were computed. 相似文献
5.
P. Storoniak M. Kabir J. Błażejowski 《Journal of Thermal Analysis and Calorimetry》2008,93(3):727-732
The enthalpies of formation of PbCl4, PbCl5− and PbCl62−, originating from quantum mechanics, have enabled the thermodynamic behaviour of these ions with respect to Cl-detachment
to be assessed. The stability of salts containing PbCl5− and PbCl62− as a function of the dimensions of these anions and complementary cations was studied using an approach combining the Kapustinskii-Yatsimirskii
equation with basic thermochemical relationships.
It was found that hexachloroplumbates of monovalent metal cations will not dissociate into metal chlorides and PbCl4, provided the complementary cations are suitably large in size. Hexachloroplumbates of divalent metal cations have not yet
been synthesised since no known metal cations attain the requisite large size. Such salts will not dissociate if the divalent
metal cations are able to complex suitably large electron-donating ligands. The pentachloroplumbates of both monovalent and
divalent metal cations are unstable, since no known metal cations have appropriately large ionic radii. The approach adopted
appears to be useful for the examination of the thermal behaviour, stability and reactivity of chloroplumbates. 相似文献
6.
A. Yu. Bykov G. A. Razgonyaeva N. N. Mal’tseva K. Yu. Zhizhin N. T. Kuznetsov 《Russian Journal of Inorganic Chemistry》2012,57(4):471-473
A new method of synthesis of the B3H8− anion has been suggested. The method uses the reaction of some metal halides (CuCl, SnCl2, CrCl3, PbF2, PbCl2, PbBr2, and BiCl3) with sodium tetrahydroborate. It is characterized by high (up to quantitative) yields and simplicity of isolation of the
target products ((n-C4H9)4N)[B3H8] and Cs[B3H8]. 相似文献
7.
S. Menecier S. Valette P. Denoirjean P. Lefort 《Journal of Thermal Analysis and Calorimetry》2012,107(2):607-616
In this article, corrosion of Invar® in a static carbon dioxide atmosphere \( 2\times 1 0^{4} \le P_{{{\text{CO}}_{ 2} }} \le 10^{5} \,{\text{Pa}} \) has been studied between 1163 and 1263 K. At the beginning, after a short initial deceleration for weight gains Δm/S <0.5 mg cm?2, oxidation kinetics were linear up to weight gains of about 4.0 mg cm?2, and only wüstite Fe1?x O was formed with a constant rate r (mg cm?2 s?1) \( r = \frac{{{\text{d}}\left( {\frac{\Updelta m}{S}} \right)}}{{{\text{d}}t}} = 0.41 \times P_{{{\text{CO}}_{ 2} }} \exp \left( {\frac{ - 198000}{RT}} \right) \) where R is the gas constant and t the time (s). Reaction mechanism is similar to that of the pure iron in analogous conditions, with the same rate limiting step i.e. external reaction of CO2 with wüstite and outward diffusion of ions Fe2+ (not limiting). For weight gains Δm/S higher than 4 mg cm?2, the limiting step changes, with an increase of the reaction rate and an internal oxidation. The origin of this mechanism change lies in the microcracks appearing in the oxide during its growth. Then, wüstite is no longer bound to the substrate; outward diffusion of ions Fe2+ stops and a topotactic transformation converts wüstite into magnetite. 相似文献
8.
V. A. Nadolinnyi T. M. Polyanskaya M. K. Drozdova O. V. Antonova A. A. Ryadun V. V. Volkov 《Russian Journal of Coordination Chemistry》2010,36(5):370-377
The influence of specific features of the structure and nature of the cations (Ph4P+, H(Phen)+, Cs+, and (CH3)4N+) on the ERP spectra of the nickel ions in salts with the dicarbollylnickelate anion [Ni(B9C2H11)2]− is studied. It is shown that the change in the cation type in these compounds results in the electron density redistribution,
which affects the change in the main and average values of the g factor. The g
av value increases over that observed in frozen solutions upon the localization of the positive charge of the cation on one
atom and in the absence of the screening effect of the solvent and large functional groups of the cation. The exception is
the compound (Ph4P+)NiCb2− (Cb is B9C2H11) with solvated CCl4 molecules. For all compounds studied, the temperature dependence of the linewidths in the EPR spectra is described by the
equation ΔH = αT + βT7 with different α and β values and is defined by the temperature dependence of the relaxation process caused by the Raman
interaction. 相似文献
9.
S. Hosein Mousavipour Fatemeh Keshavarz Sara Soleimanzadegan 《Journal of the Iranian Chemical Society》2016,13(6):1115-1124
Quasi-classical trajectory calculations and stochastic one-dimensional chemical master equation simulation methods are used to study the dynamics of the reaction of amidogen radical [NH2(2B1)] with hydroperoxyl radical [HO2(2A″)] on the lowest singlet electronic state. The title complex reaction takes place on a multi-well multichannel potential energy surface consisting of three deep potential wells and one van der Waals complex. In quasi-classical trajectory calculations a new analytical potential energy surface based on CCSD(T)/aug-cc-pVTZ//MPW1K/6-31+G(d,p) ab initio method was driven and used to study the dynamics of the title reaction. In quasi-classical trajectory calculations, the reactive cross sections and reaction probabilities are determined for 200–2000 K relative translational energies to calculate the rate constants. The same ab initio method was used to have the necessary data for solving the one-dimensional chemical master equation to calculate the rate constants of different channels. In solving the master equation, the Lennard-Jones potential model was used to form the collision between the collider gases. The fractional populations of different intermediates and products in the early stages of the reaction were examined to determine the role of the energized intermediates and the van der Waals complex on the dynamics of the title reaction. Although the calculated total rate constants from both methods are in good agreement with the reported experimental values in the literature, the quasi-classical trajectory simulation predicts the formation of NH2O + OH as the major channel in the title reaction in accordance with the previous studies (Sumathi and Peyerimhoff, Chem. Phys. Lett., 263:742–748, 1996), while the stochastic master equation simulation predicts the formation of HNO + H2O as the major products. 相似文献
10.
Anjing Wang Junmei He Lingna Kong Naidong Zhang Tong Zheng 《Research on Chemical Intermediates》2017,43(4):2175-2186
This paper investigated the photodegradation characteristics of benzoquinones and benzoquinoneimines. The photosensitivity of benzoquinones and benzoquinoneimines were analyzed by measuring the yield of SO 4 ?· in a light/Fe2+/S2O8 2? system and the degradation mechanism of benzoquinones, then discussed benzoquinoneimines in light/Fe2+/S2O8 2? and light/S2O8 2? system. The results revealed that a more aggressive oxidation of benzoquinones and benzoquinoneimines by the sunlight/Fe2+/S2O8 2? method showed a more rapid and more complete removal of chromaticity than that of the UV/Fe2+/S2O8 2? method. It was showed that they were photosensitizers, and they could generate 1O2 and O 2 ?· which could promote the formation of SO 4 ?· and ·OH in the sunlight system. Nevertheless, for benzoquinones, the sunlight/S2O8 2? method was superior to the UV/S2O8 2? method. For benzoquinoneimines, the sunlight/S2O8 2? method was inferior to the UV/S2O8 2? method. In addition, the yield of SO 4 ?· in the sunlight/Fe2+/S2O8 2? system was more than that of the UV/Fe2+/S2O8 2? system. Therefore, the photosensitivity of benzoquinones is superior to benzoquinoneimines in water treatment. 相似文献
11.
V. V. Sharutin I. V. Egorova N. N. Klepikov O. K. Sharutina 《Russian Journal of Inorganic Chemistry》2010,55(7):1103-1106
The complex [Ph3P] 4 + [Bi4I16]4? · 2 Me2C=O (I) was synthesized by the reaction of triphenyl(propyl)phosphonium iodide with bismuth iodide in acetone. The crystal structure of complex I was determined by X-ray crystallography. It contains, in addition to solvent molecules, two types of crystallographically independent tetrahedral tetraphenyl(propyl)phosphonium cations and tetranuclear anions [Bi4I16]4? in a chair conformation with the bismuth atoms being in an octahedral coordination. The Bi-I distances in the anion vary within 2.8768(4)–3.2524(4) Å. 相似文献
12.
13.
E. E. Karslyan D. S. Perekalin P. V. Petrovskii K. A. Lyssenko A. R. Kudinov 《Russian Chemical Bulletin》2008,57(10):2201-2203
Naphthalene in the [CpRu(6−C10H8)]+ complex (1) is substituted for other arenes under reflux in 1,2-dichloroethane to form the [CpRu(6-arene)]+ cations (arene = C6H6, 1,2-C6H4Me2, 1,2,4,5-C6H2Me4, or C6Me6) in 70–80% yields. The reaction is accelerated in the presence of a catalytic amount of acetonitrile. The structure of [1]PF6 was established by X-ray diffraction. 相似文献
14.
Yu. V. Rakitin V. T. Kalinnikov S. G. Khodasevich V. M. Novotortsev 《Russian Journal of Coordination Chemistry》2007,33(12):891-895
The electronic structures of the complex ions [CuCl4]2? and [CuCl5]3? were analyzed in terms of the extended angular overlap model (AOM) with consideration to sd and pd mixing. The total antibonding orbital energies of these ions show no anomalies in the transition from a tetrahedron to a planar square [CuCl4]2? and from a trigonal bipyramid to a tetragonal pyramid [CuCl5]3?. Presumably, the existence of numerous intermediate forms of these complexes is mainly due to the packing effects rather than the electronic factors. 相似文献
15.
E. A. Il’inchik R. V. Gulyaev D. A. Svintsitskii K. G. Myakishev V. V. Volkov 《Russian Journal of General Chemistry》2010,80(8):1550-1556
Compounds [Et4N]2B3H8 and CsB3H8 are studied using the ESCA method. The results of analysis of the B1s electron spectra and estimation of the effective charge differences in [Et4N]2B3H8 are compared to the data of theoretical calculations of the B3H8− anion. 相似文献
16.
H. Zhao S. Bennici J. Shen A. Auroux 《Journal of Thermal Analysis and Calorimetry》2010,99(3):843-847
The surface acidic properties of sulfated vanadia–titania catalysts prepared by various methods were investigated by adsorption
microcalorimetry, using ammonia as probe molecule. The acidic characteristics of the samples were shown to be strongly affected
by the preparation method, calcination temperature, and sulfur content. The samples prepared by sol–gel and mechanical grinding
exhibited higher acidity than co-precipitated samples. Moreover, increasing the calcination temperature of co-precipitated
samples resulted in a decrease in surface area from 402 to 57 m2 g−1 and sulfur content from around 4 to 0.2 mass%, but up to a certain point generated a stronger acidity. The optimal calcination
temperature appeared to be around 673 K. 相似文献
17.
Abstract
First principle density-functional theory calculations have been carried out on the interaction of I− and I3 − with TiO2 anatase surfaces, modeled by finite clusters that range in size from 48 to 180 atoms. The total energy per TiO2 unit and the HOMO-LUMO gaps decrease with increasing the size of the clusters. Both redox species (I− and I3 −) are strongly adsorbed on the TiO2 surface with the adsorbtion of I− being stronger. Adsorption of triiodide leads to its dissociation. The positions of the HOMO and LUMO of the adsorbed systems shift negatively from their respective cluster values. Solvation effects have been modeled using the CPCM model. Introducing solvent reduces the shifting of HOMO and LUMO. Implications for dye-sensitized solar cells (DSSC) are discussed. Both the HOMO-LUMO shifting and the strong adsorption might affect the performance of the cell. 相似文献18.
Makoto Takezaki Hiroyuki Aoki Michiko Kodama Toshihiro Tominaga 《Journal of Thermal Analysis and Calorimetry》2010,101(3):1149-1153
The solubility of hexadecyltrimethylammonium tetrachloroaurate (CTA·AuCl4) in water was measured at different temperatures of 288.2, 293.2, 298.2, 303.2, and 308.2 K. The enthalpy change associated
with the formation of the CTA·AuCl4 precipitate was estimated on the basis of the van’t Hoff equation and was found to be −42.5 ± 2.8 kJ mol−1 at 298.2 K. The calorimetric enthalpy change for the CTA·AuCl4 precipitate formation was directly determined by isothermal titration calorimetry performed at 298.2 K and was found to agree
well with that estimated from the van’t Hoff equation. 相似文献
19.
The high-field 19F and 91Zr NMR method is used to study the hydrolysis and polycondensation of hexafluorozirconate ZrF62− in aqueous and water-peroxide solutions. During hydrolysis in aqueous solutions only ZrF62− and F− ions were observed by NMR, however, in the water-peroxide medium, an intermediate product of hydrolysis ([F5Zr-OO-ZrF5]4− dimer) was detected. The dimer structure is confirmed by 19F and 91Zr NMR. In high fields (19F NMR frequency > 200 MHz), the fluorine exchange between ZrF62− and F− is slow in the 19F NMR scale and has a multisite character. 相似文献
20.
It is demonstrated by simultaneous analysis of experimental data and the results of numerical simulation that, at 100 kPa,
the H2/O2 mixture self-ignites only owing to the occurrence of a chain avalanche. Self-heating becomes significant in the course of
chain combustion and strengthens the chain avalanche. The accelerating decomposition of H2O2, which results from the reaction between HO2• and H2, contributes to chain branching and determines the character of the chain thermal explosion. The role of the HO2• radical depends on the chain process conditions, consisting of chain termination as a result of the partial loss of HO2• at the initial self-acceleration stage, H atom regeneration, and participation in the second branched cycle under conditions
of accelerated H2O2 decomposition. 相似文献