Solid–liquid metastable equilibria in the quaternary system Li2SO4 + MgSO4 + Na2SO4 + H2O at T = 263.15 K

Solubility in the liquid–solid metastable system Li₂SO₄ + MgSO₄ + Na₂SO₄ + H₂O at T = 263.15 K was studied using the isothermal evaporation method. Based on experimental data, dry-salt phase and water-phase diagrams of the system were plotted. The dry-salt phase diagram of the system includes one three-salt co-saturation point, three metastable solubility isotherm curves, and three crystallization regions corresponding to lithium sulphate monohydrate (Li₂SO₄·H₂O), epsomite (MgSO₄·7H₂O), and mirabilite (Na₂SO₄·10H₂O). Neither a solid solution nor double salts were found. Based on the extended Harvie–Weare (HW) model and its temperature-dependent equation, the values of the Pitzer parameters β⁽⁰⁾, β⁽¹⁾, β⁽²⁾, and C^Φ for Li₂SO₄, MgSO₄, and Na₂SO₄, the mixed ion-interaction parameters θ_Li,Na, θ_Li,Mg, θ_Na,Mg, ΨLi,Na,SO₄${\Psi }_{\text{Li,Na,S}{\text{O}}_4}$, ΨLi,Mg,SO₄${\Psi }_{\text{Li,Mg,S}{\text{O}}_4}$, and ΨNa,Mg,SO₄${\Psi }_{\text{Na,Mg,S}{\text{O}}_4}$, and the Debye–Hückel parameter A^Φ in the quaternary system at 263.15 K were obtained. The solubility of the quaternary system Li₂SO₄ + MgSO₄ + Na₂SO₄ + H₂O at T = 263.15 K was also calculated. A comparison between the calculated and experimental results shows that the predicted solubility agrees well with experimental data.     

C60的加成反应

富勒烯化学是以全碳分子球烯为母体的新兴有机化学领域, 在材料、医学及立体化学合成方法等方面具有广泛的应用和发展前景。本文综述了C₆₀的加成反应, 较全面地展示了富勒烯的化学性质。     

Alle 16 ges?ttigten Alkohole von C1 bis C5

Ohne Zusammenfassung     

离子液体C3MIBF4和C5MIBF4溶解焓的研究

在298.15 K下利用等温环境溶解反应热量计测定了离子液体C₃MIBF₄(四氟硼酸1-甲基-3-丙基咪唑)和C₅MIBF₄(四氟硼酸1-甲基-3-戊基咪唑)不同浓度水溶液的摩尔溶解焓(Δ_sH_m). 借助Pitzer电解质溶液理论, 得到了它们的标准摩尔溶解焓 和Pitzer焓参数: 和 , 并计算了表观相对摩尔焓. 根据Glasser理论计算了离子液体晶格能, 进而估算了离子液体C₅MIBF₄和C₃MIBF₄中正离子的水化焓分别为－171 kJ•mol^－1 (C₅MI^＋)和－207 kJ•mol^－1 (C₃MI^＋).     

Synthesis,structural characterisation and thermal decomposition of a new organic–inorganic hybrid material (C5H14N2)[Cu(SO4)2(H2O)4] · H2O

The crystal structure of copper sulfate templated by 2-methylpiperazine, (C₅H₁₄N₂)[Cu(SO₄)₂(H₂O)₄] · H₂O, was investigated using single crystal X-ray diffraction data. At room temperature, it crystallises in the monoclinic P2₁/n space group with the following unit-cell parameters: a = 6.9153(1), b = 23.1295(3), c = 10.4472(1) Å, β = 104.227(1)°, V = 1619.75(4) Å³ and Z = 4. The Cu^II cation adopts a slightly distorted octahedral geometry, arising from four water molecules and two sulfate tetrahedra leading to the formation of [Cu(SO₄)₂(H₂O)₄] units. The structure consists of isolated [Cu(SO₄)₂(H₂O)₄]²⁻ anions, 2-methylpiperazinediium cations (C₅H₁₄N₂)²⁺ and water molecules connected by a three-dimensional hydrogen-bond network. The thermal decomposition of the precursor, studied by thermogravimetry and temperature-dependent X-ray powder diffraction, proceeds through four stages giving rise to the copper oxide.     

离子液体C3MIBF4和C5MIBF4溶解焓的研究

在298.15 K下利用等温环境溶解反应热量计测定了离子液体C₃MIBF₄(四氟硼酸1-甲基-3-丙基咪唑)和C₅MIBF₄(四氟硼酸1-甲基-3-戊基咪唑)不同浓度水溶液的摩尔溶解焓(Δ_sH_m). 借助Pitzer电解质溶液理论, 得到了它们的标准摩尔溶解焓 和Pitzer焓参数: 和 , 并计算了表观相对摩尔焓. 根据Glasser理论计算了离子液体晶格能, 进而估算了离子液体C₅MIBF₄和C₃MIBF₄中正离子的水化焓分别为－171 kJ•mol^－1 (C₅MI^＋)和－207 kJ•mol^－1 (C₃MI^＋).     

Dielectric Barrier Discharge Initiated Gas-Phase Decomposition of CO2 to CO and C6–C9 Alkanes to C1–C3 Hydrocarbons on Glass, Molecular Sieve 10X and TiO2/ZnO Surfaces

Atmospheric Pressure Dielectric Barrier Discharge (APDBD) initiated decomposition of CO₂ and C₆–C₉ alkanes (in Ar carrier) with uncoated and TiO₂/ZnO coated glass surfaces, and under molecular sieve 10 X packing are presented in this study. Alkanes employed include 2-methylpentane, cyclohexane, n-hexane, n-heptane, n-octane, n-nonane and their decomposition products studied include C₁–C₃ hydrocarbons viz. CH₄, C₂H₄, C₂H₆ and C₃H₈. Generally the yields of all these C₁–C₃ products increased with discharge energy, however to a major extent the parent alkane structure controlled the relative concentration profiles of the individual products. Typically the slopes of the increase in various products yield varied from 0.025 to 0.25 ppm (v/v) mm V⁻¹. However, in the case of cyclohexane the total yield of methane, ethane and propane were only ∼20% of ethylene yield. Use of TiO₂ as well as TiO₂/ZnO coated central glass electrode in the APDBD apparatus showed ∼11% enhancement in degradation efficiency. However, while overall 2-methylpentane decomposition reduced significantly to ∼30%, in case of n-octane its decomposition to the C₁–C₃ products remained unaffected. On the other hand under molecular sieve 10X packing, yield of CH₄ and C₂H₄ increased significantly in both cases.     

Solid–liquid phase equilibria in the system K2SO4–MnSO4–H2O at 298 K and 313 K

Phase equilibria studies of the system K₂SO₄–MnSO₄–H₂O published revealed discrepancies between the data presented in the literature regarding the solid phases formed at ambient temperatures. The solubility in the system at 298 K and 313 K was determined. At 298 K, the existence of the double salt K₂SO₄·3MnSO₄·5H₂O and of MnSO₄·H₂O was confirmed. The examinations at 313 K showed the formation of the stable solid phases MnSO₄·H₂O, K₂SO₄·2MnSO₄, K₂SO₄·MnSO₄·1.5H₂O, K₂SO₄ and the formation of a metastable phase K₂SO₄·MnSO₄·2H₂O.     

Collision energy effect on the H′ + BrH (ν = 0, j = 0) → H′Br + H reaction: A quasi-classical trajectory study

Theoretical studies on the dynamics of the exchange reaction H′ + BrH (ν = 0, j = 0) → H′Br + H are performed on potential energy surface (PES) (Kurosaki et al., private communication) for the ground state using the quasi-classical trajectory method. The cross sections, computed at the collision energies (E_c) of 0.5-2.0 eV, are in good agreement with the earlier quantum wave packet results. The rotational, vibrational, and translational fractions in the total energy and the vibrational distribution for the product molecule are calculated at the same collision-energy range. The results support the repulsive character of the PES. In the considered E_c range, it has little chance to occur in an indirect reaction. The alignment and orientation of the product H′Br are investigated in detail with stereodynamics. The results show that E_c can effect on both the alignment and the orientation of product.     

Die 3,5-Dinitrobenzoes?ureester aliphatischer Alkohole imBereich von C1 bis C12

Ohne Zusammenfassung     

Zur Analyse von Erd?lprodukten im Bereich von C12 bis C20

Ohne Zusammenfassung     

A general route for the synthesis of hydrido-carboxylate complexes of the type MH(CO)(κ-OCOR)(PPh3)2 [M = Ru,Os; R = CH3, CH2Cl,C6H5, CH(CH3)2] and their use as precatalysts for hydrogenation and hydroformylation reactions

The synthesis and solid-state IR, ¹H and ³¹P{¹H} NMR spectroscopic characterization of complexes of the type MH(CO)(κ³-OCOR)(PPh₃)₂ [M = Ru, Os; R = CH₃, CH₂Cl, C₆H₅ and CH(CH₃)₂] are reported in this paper. These compounds were obtained by reaction of the respective cationic complex [MH(CO)(NCMe)₂(PPh₃)₂]BF₄ with the sodium salt of the corresponding carboxylic acid in a 1:1 v/v dichloromethane/methanol solution at room temperature. The spectroscopic data of these complexes and some DFT calculations reveal an octahedral geometry with a bidentated carboxylate, two equivalent triphenylphosphines in a mutually trans positions, a linear hydride and a linear carbonyl both in the cis-positions of the coordination sphere. The catalytic results indicate that these complexes are efficient and regioselective precatalysts for the quinoline hydrogenation and for the hydroformylation of 1-hexene, under mild reaction conditions (130 °C and 4 atm H₂ and 120 °C and 15 atm H₂/CO, respectively). For benzothiophene hydrogenation, the osmium complexes showed low activities whereas the analogous ruthenium complexes were catalytically inactive under somewhat more drastic reaction conditions to those of the quinoline hydrogenation (140 °C and 10 atm H₂).     

X-ray characterization of Te(S2CNC5H10)2 and TeI2[(C13H10N2S)2] · 4C4H8TeI2; the first Te–C bond cleaved products obtained in the substitution reactions of organo(heterocyclic)tellurium(IV) derivatives

The reaction of organo(heterocyclic)tellurium(IV) derivative: C₈H₈TeI₂(1,3-dihydro-2λ⁴-benzotellurole-2,2-diyl diiodide) with NH₄S₂CNC₅H₁₀ (ammonium piperidine dithiocarbamate) gives C₈H₈Te(S₂CNC₅H₁₀)₂ (1) and Te(S₂CNC₅H₁₀)₂ (2) or C₈H₈TeI(S₂CNC₅H₁₀) (5) according to the reaction conditions. In such type of metathetical reactions, the formation of 2 is unprecedented and it corresponds to the first Te–C cleaved product. The reaction of 2 with CH₃I, yields the oxidative addition product, CH₃TeI(S₂CNC₅H₁₀)₂ (8). The formation of 2 is also supported through Quantum Chemical calculations. Another Te–C bond cleaved product TeI₂[(C₁₃H₁₀N₂S)₂] · 4C₄H₈TeI₂ (9) is obtained in the reaction of C₄H₈TeI₂ (1,1,2,3,4,5-hexahydro-1,1-diiodotellurophene) with NH₄S₂CNHC₆H₅ (ammonium aniline dithiocarbamate). The reaction of 1,1,2,3,4,5,6-heptahydro-1-iodo-1-(morpholine dithiocarbamato) tellurane [C₅H₁₀TeI(S₂CNC₄H₈O)] (10) with 1,10-phenanthroline gives an unusual product C₁₂H₈N₂ · C₄H₁₀INO (11). The structures of the new complexes 2, 8, 9, 10 and 11 have been determined by the X-ray analysis.     

Spin fluctuations and orbital ordering in quasi-one-dimensional α-Cu(dca)2(pyz) {dca = dicyanamide = N(CN)2; pyz = pyrazine}, a molecular analogue of KCuF3

The magnetic properties of α-Cu(dca)₂(pyz) were examined by magnetic susceptibility, magnetization, inelastic neutron scattering (INS), muon-spin relaxation (μSR) measurements and by first-principles density functional theoretical (DFT) calculations and quantum Monte Carlo (QMC) simulations. The χ versus T curve shows a broad maximum at 3.5 K, and the data between 2 and 300 K is well described by an S = 1/2 Heisenberg uniform chain model with g = 2.152(1) and J/k_B = −5.4(1) K. μSR measurements, conducted down to 0.02 K and as a function of longitudinal magnetic field, show no oscillations in the muon asymmetry function A(t). This evidence, together with the lack of spin wave formation as gleaned from INS data, suggests that no long-range magnetic order takes place in α-Cu(dca)₂(pyz) down to the lowest measured temperatures. Electronic structure calculations further show that the spin exchange is significant only along the Cu–pyz–Cu chains, such that α-Cu(dca)₂(pyz) can be described by a Heisenberg antiferromagnetic chain model. Further support for this comes from the M versus B curve, which is strongly concave owing to the reduced spin dimensionality. α-Cu(dca)₂(pyz) is a molecular analogue of KCuF₃ owing to d_x2-y2${\text{d}}_{x^2-y^2}$ orbital ordering where nearest-neighbor magnetic orbital planes of the Cu²⁺ sites are orthogonal in the planes perpendicular to the Cu–pyz–Cu chains.     

Synthesis and molecular structure of new heterometal alkoxide clusters Ln2Na8(OCH2CF3)14(THF)6 (Ln = Sm, Y, Yb): Highly active catalysts for polymerization of ε-caprolactone and trimethylene carbonate

The new polynuclear heterometal alkoxide clusters Ln₂Na₈(OCH₂CF₃)₁₄(THF)₆ (Ln = Sm 1, Y 2, Yb 3) have been synthesized by the reaction of anhydrous LnCl₃ with 7 equiv. of NaOCH₂CF₃ in 68–75% yields. Crystal structural analysis revealed clusters 1–3 are isomorphous composed of two cubanes and a double open cubane, with one face of an Ln₁Na₂O₄ open cubane capped by an additional Ln₁O₂ layer. Clusters 1–3 show extremely high activity for the polymerization of ε-caprolactone (ε-CL) and trimethylene carbonate (TMC). The reactivity is much higher than those found for the monometallic alkoxides lanthanide complexes previously reported. The dependence of catalytic activity on lanthanide metals is observed: Yb ≈ Y < Sm for ε-CL and Yb < Y < Sm for TMC. The polymers obtained with these clusters all show a unimodal molecular weight distribution with moderate molecular weight distributions (M_w/M_n = 1.4–1.7), indicating that clusters 1–3 can really be used as single-component catalysts. The bimetallic cooperation and the coordination–insertion mechanism were proposed.     

Zur Trennung normaler und verzweigter aliphatischer Dicarbons?uren von C2 bis C12

Ohne Zusammenfassung     

Crystal structure and spectral characteristics of {[(C6H5)NH]2C=NH(C6H5)}[B(C6H5)4]·C2H5OH

A novel compound of {[(C₆H₅)NH]₂C=NH(C₆H₅)}[B(C₆H₅)₄]·C₂H₅OH is prepared and examined by single crystal X-ray diffraction. Crystal data: C₄₅H₄₄BN₃O, M = 653.64, monoclinic, space group P2₁/c, unit cell parameters: a = 24.375(2) Å, b = 17.5829(15) Å, c = 18.090(1) Å, β = 105.277(2)°, V = 7479.0(11) ų, Z = 8, d _calc = 1.161 g/cm³, T = 293 K, R ₁ = 0.064. The structure contains two crystallographically independent cations, two anions, and two solvate ethanol molecules. Three types of interactions occur between them: interionic N-H(N)⋯π and N(H)⋯π⋯H(C), π-delocalized system of Ph rings of the anions, and interaction of ions with ethanol molecules N-H⋯O-H(O)⋯π. The compound is characterized by IR and luminescence spectra. At room temperature, the emission intensity grows with time of exposure to UV irradiation. Original Russian Text Copyright ? 2008 by T. M. Polyanskaya, E. A. Il’inchik, V. V. Volkov, M. K. Drozdova, O. P. Yur’eva, and G. V. Romanenko __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 49, No. 3, pp. 512–521, May–June, 2008.     

Theoretical insight into stereodynamics of the O(D) + H2 (v = 0–3, j = 0) → OH + H reaction: A quasiclassical trajectory (QCT) study

In this work, the reaction O(¹D) + H₂ → OH + H has been theoretically studied using the quasiclassical trajectory (QCT) method developed by Han and co-workers. All the quasiclassical trajectory calculations are performed on the DK (Dobbyn and Knowles) potential energy surface (PES). The vector correlation information on the reaction O(¹D) + H₂ → OH + H has been obtained. It has been demonstrated that the product alignment is sensitive to the reactant vibrational quantum number (v) at collision energy of 19 kcal/mol. Moreover, with increasing the value of v, backward scattering becomes weaker and forward scattering becomes stronger.