- A study of Lux-Flood acid-base reactions in KBr melts at 800°C
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The dissociation of CO 3 2- (pK = 2.4 ± 0.2) and precipitation of MgO (pL MgO = 10.66 ± 0.1) in a KBr melt at 800°C were studied potentiometrically with the use of a Pt(O 2)|ZrO2|(Y2O3
- Rebrova,Cherginets,Ponomarenko
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- Temperature Dependence of the Gas-Phase Reaction HOSO2+O2->HO2+SO3
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We have measured the temperature dependence of the reaction HOSO2+O2->HO2+SO3.This reaction is a key step in the gas-phase oxidation of SO2 to H2SO4.The rate coefficient was measured in a low-pressure discharge flow reactor, by directly monitoring the loss of HOSO2 by chemical ionization mass spectrometry.The rate coefficient is k(T)=(1.34+/-0.25)x10-12 exp cm3 molecule-1 s-1 for the temperature range 297 KT423 K.Measurements at lower temperatures were not possible because of HOSO2 loss on the reactor wall.
- Gleason, James F.,Howard, Carleton J.
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- Thermoanalytical studies of silver and lead jarosites and their solid solutions
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Dynamic and controlled rate thermal analysis has been used to characterise synthesised jarosites of formula [M(Fe)3(SO4) 2(OH)6] where M is Pb, Ag or Pb-Ag mixtures. Thermal decomposition occurs in a series of steps. (a) dehydration, (b) well defined dehydroxylation and (c) desulphation. CRTA offers a better resolution and a more detailed interpretation of water formation processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of water formation reveal the subtle nature of dehydration and dehydroxylation. CRTA offers a better resolution and a more detailed interpretation of the decomposition processes via approaching equilibrium conditions of decomposition through the elimination of the slow transfer of heat to the sample as a controlling parameter on the process of decomposition. Constant-rate decomposition processes of non-isothermal nature reveal separation of the dehydroxylation steps, since in these cases a higher energy (higher temperature) is needed to drive out gaseous decomposition products through a decreasing space at a constant, pre-set rate.
- Frost, Ray L.,Palmer, Sara J.,Kristof, Janos,Horvath, Erzsebet
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- Degradation resistance of cordierite diesel particulate filters to diesel fuel ash deposits
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The thermochemical degradation resistance of a typical cordierite diesel particulate filter (DPF) material by synthetic ashes typical of those arising in practice has been investigated over the temperature range 950°C-1250°C. Differential thermal analyses and heat treatment of pressed pellets were used to characterize the melting/transformation behavior of ashes representative of typical diesel fuel (ash A) and those typical of when the catalysts ferrocene (ash FeA) and cerium carboxylate (ash CeA) were present in the fuel and to study the interaction chemistry between powdered cordierite and the ash compositions. Additional experiments involved the application of surface coverings of ash to DPF specimens. The results obtained showed that filter performance would not be compromised by ash liquefaction/sintering as long as temperatures did not exceed 900°C for ash A, 970°C for ash FeA and 1100°C for ash CeA. For long time periods, compared to the expected application durations, liquid phosphates dissolve cordierite leading to the formation of Zn and Fe aluminate spinels. Overall, the results clearly indicate that thermochemical degradation of cordierite by ashes under conditions representative of typical diesel engine systems is highly unlikely at temperatures of 1100°C and below.
- Pomeroy,O'Sullivan,Hampshire,Murtagh
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- Synthesis and structural characterization of fluorosulfate derivatives of silver(II)
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The synthesis of silver(II) fluorosulfate, Ag(SO3F)2, by a variety of routes is described. The preparations of a mixed-valency compound of the composition Ag3(SO3F)4 and its potassium analogue K2AgII(SO3F)4, the compounds AgIIPtIV(SO3F)6 and AgIISnIV(SO3F)6, and the complex [Ag(bpy)2](SO3F)2 are also reported. Structural studies are based on vibrational, electronic mull and diffuse reflectance, and ESR spectra as well as magnetic susceptibility measurements in the temperature range of 80 to about 300 K. Both Ag3(SO3F)4 and K2Ag(SO3F)4 show antiferromagnetic coupling. All other divalent silver compounds synthesized here are magnetically dilute with the Ag2+ ion in a square-planar or tetragonally distorted (elongated) octahedral environment.
- Leung,Aubke
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- Two Ce(SO4)2·4H2O polymorphs: Crystal structure and thermal behavior
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Syntheses, crystal structures and thermal behavior of two polymorphic forms of Ce(SO4)2·4H2O are reported. The first modification, α-Ce(SO4)2·4H2O (I), crystallizes in the orthorhombic space group Fddd, with a=5.6587(1), b=12.0469(2), c=26.7201(3) A and Z=8. The second modification, β-Ce(SO4)2·4H2O (II), crystallizes in the orthorhombic space group Pnma, with a=14.6019(2), b=11.0546(2), c=5.6340(1) A and Z=4. In both structures, the cerium atoms have eight ligands: four water molecules and four sulfate groups. The mutual position of the ligands differs in (I) and (II), resulting in geometrical isomerism. Both these structures are built up by layers of Ce(H2O)4(SO4)2 held together by a hydrogen bonding network. The dehydration of Ce(SO4)2·4H2O is a two step (I) and one step (II) process, respectively, forming Ce(SO4)2 in both cases. During the decomposition of the anhydrous form, Ce(SO4)2, into the final product CeO2, intermediate xCeO2·yCe(SO4)2 species are formed.
- Casari, Barbara M.,Langer, Vratislav
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- Formation Mechanism of Condensation Nuclei in Nighttime Atmosphere and the Kinetics of the SO2-O3-NO2 System
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An experimental study of condensation nuclei formation for the systen of SO2-O3-NO2-water vapor-zero grade air at 1 atm and room temperature has been conducted.In the experiments, nitrogen dioxide and ozone were mixed to generate NO3 and N2O5; the O3/NO2/NO3/N2O5 mixture and sulfur dioxide and water vapor were introduced into a specially designed sheath flow reaction vessel in which the oxidation of sulfur dioxide by NO3 and N2O5 occurred to produce condensation nuclei which were quantitatively determined.The results of several series of experiments accomplished at different concentrations of each of the reactants are presented.The correlations of observed concentrations of condensation nuclei to concentrations of sulfur dioxide, nitrogen dioxide, ozone, and water vapor are evaluated.A model of the mechanism of condensation nuclei formation in nighttime atmosphere is established.From the kinetic analysis of the experimental results, estimates are derived for the rate constants of the following reactions, SO2 + NO3 -> SO3 + NO2, k -21 cm3 molecule-1 s-1; and SO2 + NO2 -> SO3 + N2O4, k = 9.1 x 10-24 cm3 molecule-1 s-1, at 26.5 deg C, which are below the upper limit values reported previously.
- Xie, Zhilong Diane
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- Synthesis, vibrational spectra, and structure of divalent metal peroxodisulfates
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Simple strontium peroxodisulfate SrS2O8 ? 4H2O was synthesized by the reaction of solid Sr(OH)2 ? 8H2O taken in 30% excess with an aqueous solution of (NH 4)2S2O8
- Skogareva,Minaeva,Filippova
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- Kinetics of the Reaction OH + SO2 in He, N2 and O2 at Low Pressure
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The rate constants of the gas-phase reaction of OH with SO2 for M = He, N2,and SO2 have been determined by using the discharge flow/resonance fluorescence technique.The termonuclear rate constants (all in units of cm6 molecule -2 ss
- Lee, Yin-Yu,Kao, Wen-Chuen,Lee, Yuan-pern
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- Reaction of sulfur dioxide with Ni(1 0 0) and Ni(1 0 0)-p(2 × 2)-O
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XPS, TPD, LEED and STM have been used to probe the interaction between sulfur dioxide and the Ni(1 0 0) and Ni(1 0 0)-p(2 × 2)-O surfaces. On Ni(1 0 0) at 300 K SO2 disproportionates according to 2SO2 → S(a) + SO3(a) + O(a). Sulfur and sulfite occupy sites in a p(2 × 2) arrangement, while oxygen adsorbs into c(2 × 2) domains amid Ni chains of (n√2×2√2)R45°/ (2√2×n√2)R45° (n = 7-12) periodicity that are presumed to be due to segregation of oxygen to the subsurface. On Ni(1 0 0)-p(2 × 2)-O at 300 K SO2(a) reacts with O(a) to form SO3(a). Sulfite adsorbs into p(2 × 2) islands encompassed by c(2 × 2)-O. TPD measurements with 18O are suggestive of a monodentate sulfite binding configuration.
- Alemozafar, Ali R.,Madix, Robert J.
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- Synthesis and Crystal Structure of Tetraphenylbismuth Benzenesulfonate Hydrate and Tetraphenylbismuth 3,4-Dimethylbenzenesulfonate
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The reaction of pentaphenylbismuth with SO3 or with triphenylbismuth bis(benzenesulfonate) in benzene gave tetraphenylbismuth benzenesulfonate monohydrate (I). Tetraphenylbismuth 3,4- dimethylbenzenesulfonate (II) was prepared from pentaphenylbismuth and triphenylbismuth bis(3,4-dimethylbenzenesulfonate) in benzene. The structures of compounds I and II were established by X-ray diffraction. The Bi atoms have a distorted trigonal-bipyramidal coordination where the arenesulfonate group occupies an axial position. The Bi-C(average) and Bi-O distances in molecules I and II are 2.204(2), 2.695(2) A and 2.205(2), 2.728(2) A, respectively.
- Sharutin,Egorova,Ivanenko,Sharutina,Popov
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- S6N2O15—A Nitrogen-Poor Sulfur Nitride Oxide, and the Anhydride of Nitrido-tris-Sulfuric Acid
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The reaction of hexachlorophosphazene, P3N3Cl6, with SO3 leads to the new sulfur nitride oxide S6N2O15. The compound displays an extraordinarily low nitrogen content and exhibits a bicyclic cage structure according to the formulation N{S(O)2O(O)2S}3N, with both nitrogen atoms in trigonal planar coordination of sulfur atoms. Interestingly, the new nitride oxide can be also seen as the anhydride of nitrido-tris-sulfuric acid, N(SO3H)3.
- Wickleder, Mathias S.,van Gerven, David
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- Discharge Flow Measurements of the Rate Constants for the Reactions OH+SO2+He and HOSO2+O2 in Relation with the Atmospheric Oxidation of SO2
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The reactions OH+SO2+M (M=He, SO2)->HOSO2 (1) and HOSO2+O2 (2) have been studied by the discharge flow EPR technique at room temperature and at pressures ranging from 1 to 6.4 Torr in a halocarbon-wax-coated reactor.For He and SO2 as the third body the bimolecular rate constant can be expressed as k1(He)=(8.1+/-0.2)*10-32+(2.4+/-0.4)*10-15 (P=1-6.4 Torr) and k1(SO2)=(1.3+/-0.4)*10-30 (P0.1 Torr).Units are cubic centimeters per molecular per second.Reaction 2 was studied by adding O2 to the reacting medium and NO for the conversion of HO2 into OH.The value of k2 was found from the computer fitting of the OH profiles with and without added O2 as a function of reaction time: k2=(3.5+/-1)*10-13 cm3 molecule-1 s-1.
- Martin, D.,Jourdain, J. L.,Bras, G. Le
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- A molecular approach for unraveling surface phase transitions: Sulfation of BaO as a model NOx trap
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SO3-induced surface reconstruction: The SO3 molecule as a multidentate ligand induces remarkable surface reconstruction phenomena on alkaline earth oxide surface. By using ab initio computations, adsorption properties are derived to elucidate the thermodynamics of the SO3-BaO system. Copyright
- Rankovic, Nikola,Chizallet, Celine,Nicolle, Andre,Da Costa, Patrick
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- Adsorption and reactivity of SO2 on Ir(1 1 1) and Rh(1 1 1)
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The adsorption and reactivity of SO2 on the Ir(1 1 1) and Rh(1 1 1) surfaces were studied by surface science techniques. X-ray photoelectron spectroscopy measurements showed that SO2 was molecularly adsorbed on both the Ir(1 1 1) sur
- Fujitani,Nakamura,Kobayashi,Takahashi,Haneda,Hamada
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- Influence of heating rate on kinetic quantities of solid phase thermal decomposition
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Thermogravimetric analyses of thermal decomposition (pyrolysis, thermal dissociation and combustion) of 9 different samples were carried out in dynamic conditions at different heating rates. The kinetic parameters (E, A and k m) of thermal decomposition were determined and interrelations between the parameters and heating rate q were analyzed. There were also relations between Arrhenius and Eyring equations analyzed for thermal decomposition of solid phase. It was concluded that Eyring theory is an element, which interconnects used thermokinetic equations containing Arrhenius law and suggests considering kinetic quantities in way relative to 3 kinetic constants (E, A and km). Analysis of quantities other than km (i.e. E, A, Δ+H, Δ+S) in relation to heating rate is an incomplete method and does not lead to unambiguous conclusions. It was ascertained that in ideal case, assuming constant values of kinetic parameters (E and A) towards heating rate and satisfying both Kissinger equations, reaction rate constant km should take on values intermediate between constants (km)1 and (km)2 determined from these equations. Whereas behavior of parameters E and A towards q were not subjected to any rule, then plotting relation km vs. q in the background of (km)1 and (km)2 made possible classification of differences between thermal decomposition processes taking place in oxidizing and oxygen-free atmosphere.
- Bigda,Mianowski
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- Synthesis, identification and thermal decomposition of double sulphates of some lanthanides and Y with ethanolammonium cation
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On evaporation at room temperature of an aqueous mixture of Ln(III) sulphate and ethanolammonium sulphate in a molar ratio higher than 1:12, in the presence of sulphuric acid, double sulphates of Sm, Eu, Ho, Tm, Yb and Y with a waxy feel were obtained. The stoichiometry of the obtained compounds was determined by means of elemental and TG analysis. On the basis of X-ray powder diffraction patterns it was concluded that an isostructural group with a general formula: Ln2(HOCH2CH2NH3)8(SO4)7·8H2O was obtained. The above compounds have a stoichiometry and a crystal structure different from those of the double sulphates of La, Ce, Pr and Nd with the same monovalent cation, as presented earlier. The thermal decomposition of the investigated compounds in the temperature range from ambient temperature up to 1173 K occurred in a similar way, mainly in three not well-differentiated steps. Lanthanide oxysulphates were obtained as final products.
- Jordanovska,Trojko
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- Magnetic structure and properties of Cu3(OH)4SO 4 made of triple chains of spins s=1/2
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Cu3(OH)4SO4, obtained by hydrothermal synthesis from copper sulfate and soda in aqueous medium, is isostructural with the corresponding antlerite mineral, orthorhombic, space group Pnma (62), with a=8.289(1) b=6.079(1) and c=12.057(1)A, V=607.5(2) A3, Z=4. Its crystalline structure has been refined from X-ray single crystal and powder neutron diffraction data at room temperature. It consists of copper (II) triple chains, running in the b-axis direction and connected to each other by sulfate groups. The magnetic structure, solved from powder neutron diffraction data at 1.4K below the transition at 5K evidenced by susceptibility and specific measurements, reveals that, inside a triple chain, the magnetic moments of the copper ions (μB=0.88(5) at 1.4K) belonging to outer chains are oriented along the c-axis of the nuclear cell, with ferromagnetic order inside a chain and antiferromagnetic order between the two outer chains. No long-range magnetic order is obtained along the central chain with an idle spin behavior.
- Vilminot,Richard-Plouet,Andre,Swierczynski,Guillot,Bouree-Vigneron,Drillon
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- Structure of vanadium oxosulfato complexes in V2O5-M2S2O7-M2 SO4 (M = K, Cs) melts. A high temperature spectroscopic study
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The VV and VIV oxosulfato Complexes formed in V2O5-M2S2O7-M2 SO4 (M = K, Cs) melts under SO2(g) or O2(g) atmosphere have been studied by electronic absorption (VIS/NIR) and Raman spectroscopy at 450 ?°C. VIS/NIR spectra have been obtained at 450 ?°C for V2O5-K2S2O7 molten mixtures in SO2 atmosphere (PSO2 = 0-1.2 atm). The data are in agreement with the VV a?? VIV equilibrium: (VO)2O(SO4)44-(l) + SO2(g) a?? 2VO(SO4)22-(l) + SO3(g). SO2 does not coordinate to the VV complex but starts significantly to coordinate to VIV for PSO2 > 0.4 atm according to VO(SO4)22-(l) + SO2(g) a?? VO(SO4)2SO22-(l). The Raman spectral features and the exploitation of the relative Raman intensities indicate that the (VO)2O(SO4)44- dimeric complex unit, possessing a V-O-V bridge, is formed in the V2O5-M2S2O7 binary mixtures. The spectral changes occurring upon interaction of the binary V2O5-K2S2O7 mixtures with SO2 or addition of M2SO4 to the binary V2O5-M2S2O7 mixtures indicate a cleavage of the V-O-V bridge and formation of the VIVO(SO4)22- or VVO2(SO4)23- monomeric complex units, respectively. The most characteristic bands due to the various complexes in the melts have been assigned. The spectral data are discussed in terms of possible structures. For the first time, high-temperature vibrational spectroscopy has been used to study the structural and vibrational properties of V2O5-K2S2O7 and V2O5-K2S2O7-K2 SO4 melts. The results are valuable for the mechanistic understanding of SO2 oxidation at the molecular level.
- Boghosian, Soghomon,Chrissanthopoulos, Athanassios,Fehrmann, Rasmus
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- Thermal stability of the soil minerals destinezite and diadochite Fe 3+2(PO4)(SO4)(OH)·6H 2O - Implications for soils in bush fires
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Thermogravimetry combined with evolved gas mass spectrometry has been used to ascertain the stability of the soil minerals destinezite and diadochite Fe3+2(PO4)(SO4)(OH)·6H 2O. These two minerals are identical except for their morphology. Diadochite is amorphous whereas destinezite is crystalline. Both minerals are found in soils. It is important to understand the stability of these minerals because soils are subject to bush fires especially in Australia. The thermal analysis patterns of the two minerals are similar but not identical. Subtle differences are observed in the DTG patterns. For destinezite, two DTG peaks are observed at 129 and 182 °C attributed to the loss of hydration water, whereas only a broad peak with maximum at 84 °C is observed for diadochite. Higher temperature mass losses at 685 °C for destinezite and 655 °C for diadochite, are due to sulphate decomposition, based upon the ion current curves. This research has shown that at low temperatures the minerals are stable but at high temperatures, as might be experienced in a severe bush fire, the minerals decompose.
- Frost, Ray L.,Palmer, Sara J.
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- Solvothermal synthesis, crystal structure and properties of three new 1D and 3D organically templated lanthanide sulfates
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Three new organic amine templated lanthanide sulfates [(CH 3)2NH2]3[Y(SO4) 3]·H2O 1 and [(CH3)2NH 2]9[Ln5(SO4)12] ·2H2O (Ln = La 2 and Ce 3) have been solvothermally synthesized under similar conditions and structurally characterized by single-crystal X-ray diffraction. Compound 1 exhibits 1D anionic chain structure compensated by protonated dimethylamine occluded in the helical [Y-O-S] n chains, while the 3D inorganic frameworks of 2 and 3 contain extra-large 20-membered ring channels. The syntheses of three compounds demonstrates that although yttrium and lanthanide belong to one family, the self-assembly of yttrium sulfate may be different from other rare-earth sulfates because Y is much lighter. The formation of 1-3 also demonstrates that the solvent plays an important role during the synthesis.
- Fu, Jie,Zheng, Lei,Zhang, Zhibin,Xu, Yan
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- The local structure of SO2 and SO3 on Ni(1 1 1)
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The normal incidence X-ray standing wave (NIXSW) technique, supported by X-ray photoelectron spectroscopy and near-edge X-ray absorption fine structure (NEXAFS), has been used to determine the local adsorption geometry of SO 2 and SO3 on Ni(1 1 1). Chemical-state specific NIXSW data for coadsorbed SO3 and S, formed by the disproportionation of adsorbed SO2 after heating from 140 K to 270 K, were obtained using S 1s photoemission detection. For adsorbed SO2 at 140 K the new results confirm those of an earlier study [Jackson et al., Surf. Sci. 389 (1997) 223] that the molecule is located above hollow sites with its molecular plane parallel to the surface and the S and O atoms in off-atop sites; corrections to account for the non-dipole effects in the interpretation of the NIXSW monitored by S 1s and O 1s photoemission, not included in the earlier work, remove the need for any significant adsorption-induced distortion of the SO2 in this structure. SO3, not previously investigated, is found to occupy an off-bridge site with the C3v axis slightly tilted relative to the surface normal and with one O atom in an off-atop site and the other two O atoms roughly between bridge and hollow sites. The O atoms are approximately 0.87 ? closer to the surface than the S atom. This general bonding orientation for SO3 is similar to that found on Cu(1 1 1) and Cu(1 0 0) both experimentally and theoretically, although the detailed adsorption sites differ.
- Jackson,Woodruff,Chan,Jones, Robert G.,Cowie
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- Solvothermal synthesis, crystal structure and properties of the first organic-templated holmium sulfate [C2N2H 10]3[Ho2(SO4)6· 2H2O]
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The first organic amine-templated holmium sulfate [C2N 2H10]3[Ho2(SO4) 6·2H2O] (1) has been synthesized solvo-thermally and has been structurally characterized by sing
- Zhou, Wanli,Chen, Qi,Zhu, Dunru,Xu, Yan
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- Oxidation of Sulphur Dioxide using Micro- and Nanoparticles of various Iron Oxides
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Sulphuric acid is the chemical with highest production rates in the world. At present, it is mainly synthesized using vanadium pentoxide as catalyst, which determines the applied production process particularly in terms of gas pre-treatment and heat management. For processes, which cannot be run with vanadium pentoxide, alternative catalysts are required to make different SO2 qualities accessible to sulphuric acid production. Ferric oxides are a very promising alternative, since they combine higher thermal with improved chemical stability. Within this study, various ferric oxides were examined with regard to conversion rates and structural changes during application. Effects of crystal structure, particle size as well as thermal treatment and the influence of precipitation conditions were studied. Although conversion rates are very promising, it has become apparent, though, that these materials cannot compete with vanadium pentoxide in terms of conversion rate as well as long-time stability, yet. Nevertheless, from the results of this study, it is clear that high potential lies in focused catalyst optimisation.
- Reichelt, Lydia,Hippmann, Sebastian,Brichkin, Vyacheslav Nikolayevich,Bertau, Martin
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- Catalytic properties of the thermal decomposition products of Zr(SO4)2 · 4H2o
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The catalytic activity of the thermal decomposition products of Zr(SO4)2 · 4H2O in the reactions of 1-butene isomerization to 2-butenes, isobutanol dehydration, and n-butane skeletal isomerization was studied. Their behavi
- Kotsarenko,Shmachkova
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- Kinetics of the Gas-Phase Reaction HOSO2 + O2 -> HO2 + SO3
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A flowing afterglow technique was adapted for use as a chemical ionization detector for kinetic measurements.Reactants and products from a radical flow tube reactor are injected into the flowing afterglow for detection via subsequent ion-molecule reactions.This system has been used to study the reaction HOSO2 + O2 -> HO2 + SO3, which is the second step in the homogeneous gas-phase oxidation of SO2 to H2SO4.Both the HOSO2 reactant and the SO3 product were detected by using Cl- as the chemical ionization reagent.The rate coefficient, which was determined by monitoring the loss of the HOSO2 reactant, is (4.37 +/- 0.66) x 1E-13 cm3 molecule-1 s-1 at 298 K.This result supports earlier studies which claimed that odd hydrogen radicals (HOx) are catalysts in the gas-phase oxidation of SO2.
- Gleason, James F.,Sinha, Amitabha,Howard, Carleton J.
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- Synthesis and characterization of molybdenum(VI) oxide sulfates and crystal structures of two polymorphs of MoO2(SO4)
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Reactions between α-MoO3 or MoO3·0.43H2O and 65-95 wt% H2SO4 were studied from room temperature up to the boiling point of the acid. Four new compounds, MoO2(SO4), (modifications I, II and III) and MoO2(SO4)·H2SO4·H 2O, have been isolated depending on the H2SO4 concentration, reaction temperature, reaction time and molybdenum source. The characterization of these phases was performed with powder X-ray diffraction, thermogravimetric analysis, differential thermal analysis, chemical analysis and density measurements. Both starting materials react with sulfuric acid and form MoO2(SO4) II at temperatures above ca. 75 °C. This compound is unstable in the reaction mixture and converts into MoO2(SO4) I or III depending on time and temperature. The three modifications of MoO2(SO4) are hygroscopic and decomposition in moist air is studied for the I and II modifications. On heating, all modifications of MoO2(SO4) decompose into α-MoO3 or a mixture of α-MoO3 and β-MoO3 depending on heating rate and sample size. The three-dimensional, open-framework structures of I and II, have been determined from single-crystal X-ray diffraction data. I crystallizes in the monoclinic space group C2/c and II in the orthorhombic space group Pna21. Both structures are made up of MoO6 octahedra and SO4 tetrahedra and contain layers of eight- and four-membered rings of alternating, corner-sharing octahedra and tetrahedra. These layers are linked (also via Mo-S bridges) to form a three-dimensional framework. The MoO6 octahedra are rather distorted, as demonstrated by large variations in the bonding Mo-O interatomic distances, which reflect the double-bond character of the binding between molybdenum and terminal oxygen atoms pointing into the eight-membered rings. The SO4 tetrahedra are quite regular. The structural relation to MoO2(SO4) III is briefly considered.
- Christiansen, Alexander F.,Fjellvag, Helmer,Kjekshus, Arne,Klewe, Bernt
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- Thermal analysis for identification of E-beam nanosize ammonium sulfate
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Thermal decomposition of nanosize ammonium sulfate obtained as a by-product in a new electron-beam technology cleaning up waste gases from thermal power stations was studied. DTA-TG-DTG curves were used to characterize thermal properties of the new products obtained under different technological conditions. High quality of ammonium sulfate from Merck was used as a reference material. Ammonium sulfate was the main component in all the products and their thermal behavior was similar to that of the reference. Only the solid product obtained with the highest norm of ammonia contained about 3.2% ammonium nitrate. Thermoanalytical methods can successfully be applied for control the quality of the by-products from E-beam desulfurization technology. It was found that the thermal stability of the nanosize ammonium sulfate was the same as that of the reference ammonium sulfate.
- Petkova,Pelovski,Hristova
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- Coordination compounds of copper(II) with new 1,4-benzothiazino-[2,3-b]phenothiazine derivatives
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New coordination compounds of copper(II) with 1,4-benzothiazino[2,3-b]phenothiazine derivatives (L) of the molecular formulas [Cu(L)·+Cl3-] were synthesized and characterized by spectral (IR, UV-Vis, ESR) and thermal analy
- Ghizdavu, Letitia,Cristea, Castelia,Silberg,Balan, Craita,David
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- Capture of SO3 isomers in the oxidation of sulfur monoxide with molecular oxygen
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When mixing SO with O2 in N2, Ne, or Ar, an end-on complex OS-OO forms in the gas phase and can subsequently be trapped at cryogenic temperatures (2.8-15.0 K). Upon infrared light irradiation, OS-OO converts to SO3 and SO2 + O with the concomitant formation of a rare 1,2,3-dioxathiirane 2-oxide, i.e., cyclic OS(O)O. Unexpectedly, the ring-closure of 16OS-18O18O yields a ca. 2:1 mixture of cyclic 18OS(16O)18O and 16OS(18O)18O. The characterization of OS-OO and OS(O)O with IR and UV/Vis spectroscopy is supported by high-level ab initio computations.
- Wu, Zhuang,Lu, Bo,Feng, Ruijuan,Xu, Jian,Lu, Yan,Wan, Huabin,Eckhardt, André K.,Schreiner, Peter R.,Xie, Changjian,Guo, Hua,Zeng, Xiaoqing
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supporting information
p. 1690 - 1693
(2018/02/21)
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- Does Tetrahydrofuran (THF) Behave like a Solvent or a Reactant in the Photolysis of Thionyl Chloride (Cl2SO) in Cyclohexane? A Transient Infrared Difference Study
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The photolysis of thionyl chloride (Cl2SO) in pure cyclohexane (cHex) and in cHex with a small amount of tetrahydrofuran (THF) irradiated with 266 nm pulsed laser was investigated using time-resolved step-scan Fourier-transform spectroscopy. The density functional theory B3LYP, with the conductor-like polarizable continuum model to account for the effects of solvents, was employed to predict the molecular parameters of the relevant species. Monitoring the wavenumbers and infrared absorbances attributed to the [S,O] species and accounting for the stoichiometry revealed SO2 to be the major oxygen-containing end product for the thermal decomposition of Cl2SO. Upon successive irradiation with 266 nm pulsed laser, the major product, as detected by IR absorption, was S2O with minor SO3, which could be generated from the secondary reactions of the photolytic intermediate ClSO. The majority of the transient vibrational features upon 266 nm irradiation of the mixture of Cl2SO/cHex was attributed to ClSO, characterized at 1155 cm-1, coupled with a minor contribution of (ClSO)2 at 1212 and 1173 cm-1. For the mixture of Cl2SO/THF/cHex, the transient population of ClSO was retained, but the amount of (ClSO)2 was slightly reduced, coupled with a new upward feature at 1054 cm-1 that was plausibly attributed to the C-O-C asymmetric stretching mode of ClSO-THF complex. Upon the successive irradiation of the Cl2SO/THF/cHex mixture, the amount of S2O was also decreased. The observed complexes of THF with solutes suggested that THF should not be merely treated as a solvent but regarded as a coordination molecule in organic synthesis. The formation of the intermediate-THF complexes altered the reaction pathways, as well as the types and populations of the end products.
- Shih, Meng-Chen,Chu, Li-Kang
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p. 5401 - 5408
(2018/06/04)
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- Synthesis of four-angle star-like CoAl-MMO/BiVO4 p-n heterojunction and its application in photocatalytic desulfurization
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A four-angle star-like Co-Al mixed metal oxide (CoAl-MMO)/BiVO4 heterojunction has been synthesized via a hydrothermal method and following sintering. The CoAl-MMO/BiVO4 is derived from CoAl-LDHs/BiVO4, in which CoAl-LDHs leads to a distribution of amorphous CoAl-MMO. The CoAl-MMO loading on BiVO4 greatly enhances visible light absorption, improves charge separation by band offset charge transfer, and makes flat band potential more negative. The three effects together result in excellent photocatalytic activity. Under visible light irradiation, desulfurization efficiency of thiophene has achieved up to 98.58% on CoAl-MMO/BiVO4 with molar ratio of 0.3:5.
- Yun, Limin,Yang, Zhanxu,Yu, Zong-Bao,Cai, Tianfeng,Li, Yue,Guo, Changyou,Qi, Chengyuan,Ren, Tieqiang
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p. 25455 - 25460
(2017/07/11)
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- Catalytic removal of organic colorants from water using some transition metal oxide nanoparticles synthesized under sunlight
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Transition metal oxides (TMO) constitute a most amazing class of materials with a wide range of properties and applications; therefore, their synthesis using a green approach is a necessity. As such, sunlight irradiation was employed to synthesize various TMO nanostructures (ZnO, CuO, Co3O4, NiO and Cr2O3) using water as a solvent. Nanoparticles obtained with distinct morphologies, such as nanotubes (ZnO; 3O4; 45-90 nm), needle-shaped (NiO; 2-25 nm) and nanobeads (Cr2O3; ~17 nm) were confirmed by TEM analysis. The significance of the synthesis is in its quick approach with no thermal heat involvement, reusable catalyst, cost effectiveness and ability to fabricate almost uniformly distributed nanoparticles with small sizes. The potential of the synthesized nanoparticles was examined in the treatment of simulated water containing hazardous dyes: Alizarin Red S (ARS) + Methylene Blue (MB). Interestingly, in a short period of 180 min, 88.24% of the dye mixture was, for the most part, completely degraded using Cr2O3 nano-needles, followed by 87.96% (ZnO) > 86.86% (CuO) > 85.89% (NiO) > 80.35% (Co3O4), depending on the sizes of the respective TMO nanoparticles. This is also supported by the finding of small and non-toxic by-products such as but-2-enal, sulfur trioxide and benzoquinone. With high potential observed in the removal of dyes, TMO nanoparticles have a bright future with respect to their use as important adsorbents in waste water treatment. The advantage of the present work lies in the green synthesis of nanoparticles and their application in helping to make our environment green.
- Shanker, Uma,Jassal, Vidhisha,Rani, Manviri
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p. 94989 - 94999
(2016/10/21)
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- Synthesis and properties of a branched short-alkyl polyoxyethylene ether alcohol sulfate surfactant
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A branched alkyl polyoxyethylene ether alcohol sulfate, sodium isooctyl polyoxyethylene ether sulfate (i-OE3S), was synthesized and its physic-chemical properties were investigated systematically. The experiment on Krafft point gave a result that the Krafft temperature of i-OE3S was below 0 °C. The measurement of static surface tension showed that the critical micelle concentration (cmc) and surface tension at cmc (γcmc) of i-OE3S were 21.67 mmol·L- 1 and 27.4 mN·m- 1, respectively. From the results of dynamic surface tension (DST) measurements, we could obtain that the adsorption of i-OE3S at air/liquid interface is controlled by the mixed diffusion-kinetic mechanism. Spherical assemblies with a diameter in the range of 263 to 606 nm in water were observed by transmission electron microscopy (TEM). The spreading performance of i-OE3S aqueous solution on paraffin film was investigated by dynamic contact angle and the results demonstrated that i-OE3S possessed an excellent spreading ability.
- Wang, Wanxu,Li, Jianbo,Yang, Xiaoyi,Li, Ping,Guo, Chaohua,Li, Quanhong
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p. 597 - 604
(2015/10/28)
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- Reactions of the methylsulfinyl radical [CH3(O)S] with oxygen (3O2) in solid argon
-
The atmospherically highly relevant methylsulfinyl radical (CH3(O)S) readily reacts with molecular triplet oxygen in cryogenic argon matrices containing small amounts of 3O2. Comparison of experimental and computed IR- and UV/Vis spectra, including isotope exchange, show that the initially formed 3O2 adduct has the structure of a peroxyl radical (CH3(O)SOO), which upon irradiation with UV light isomerizes to the methylsulfonoxyl radical (CH3SO3). The latter transforms into the methansulfonic acid radical (CH2SO3H) by irradiation with visible light. During the matrix photolysis small amounts of SO3 and the methyl radical were detected indicating competitive direct photodissociation.
- Reisenauer, Hans Peter,Romański, Jaros?aw,Mlostoń, Grzegorz,Schreiner, Peter R.
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supporting information
p. 10022 - 10025
(2015/06/22)
-
- Molten copper hexaoxodivanadate: An efficient catalyst for SO3 decomposition in solar thermochemical water splitting cycles
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Molten copper hexaoxodivanadate (CuV2O6) was identified as an active catalyst for SO3 decomposition, which is an oxygen generation step in solar thermochemical water splitting cycles, at moderate temperatures (ca. 600 °C). The SO3 decomposition over CuV2O6 was significantly accelerated when the reaction temperature approached the melting point (ca. 630 °C) compared with solid phases of Cu2V2O7 as well as other compounds in the CuO-V2O5 system with higher melting points (≥780 °C). A possible intermediate CuSO4 species formed by SO 3 adsorption onto the Cu oxide site may decompose promptly to evolve SO2 and O2 on contact with the molten catalyst phase. Furthermore, the molten catalyst contained a large fraction of monovalent Cu formed by spontaneous desorption of oxygen. A possible reaction mechanism consisting of the fast dissolution of CuSO4 and Cu 2+/Cu+ redox cycles in the melt is proposed.
- Kawada, Takahiro,Tajiri, Tonami,Yamashita, Hiroaki,Machida, Masato
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p. 780 - 785
(2014/03/21)
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- EARLY STRENGTHENING AGENT FOR HYDRAULIC COMPOSITION
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The present invention provides the early strengthening agent for hydraulic compositions containing a compound (a) obtained by reacting (A) one or more compounds selected from polyhydric alcohols having 3 to 20 hydroxy groups and alkylene oxide adducts thereof with (B) a sulfating agent, and the additive composition for hydraulic compositions containing the compound (a).
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- The unique bis-(disulfato)-aurate anion [Au(S2O 7)2]-: Synthesis and characterization of Li[Au(S2O7)2] and Na[Au(S2O 7)2]
-
The reaction of Au(OH)3 and oleum (65% SO3) in the presence of M2SO4 (M = Li, Na) afforded yellow single crystals of Li[Au(S2O7)2] (triclinic, P1, Z = 1, a = 532.20(3), b = 649.69(4), c = 836.72(5) pm, α = 107.982(2)°, β = 90.171(2)°, γ = 102.583(2)°, V = 267.80(3) A3) and Na[Au(S2O7) 2] (monoclinic, P21/n, Z = 2, a = 533.31(3), b = 1193.38(7), c = 907.67(5) pm, β = 98.548(3)°, V = 571.26(6) A3). Both compounds exhibit the unprecedented [Au(S 2O7)2]- anion in which a square planar coordination of the central gold atom is achieved by the chelating attachment of two disulfate groups. The disulfates were characterized by means of IR spectroscopy and DTA/TG measurements. For both compounds, the decomposition occurs via several steps and is finished at about 450 °C at the stage of elemental gold and the sulfates M2SO4 (M = Li, Na), as revealed by X-ray powder diffraction of the residues.
- Logemann, Christian,Wickleder, Mathias S.
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p. 11111 - 11116
(2012/01/14)
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- XeOF3-, an example of an AX3YE2 valence shell electron pair repulsion arrangement; Syntheses and structural characterizations of [M][XeOF3] (M = Cs, N(CH3) 4)
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The XeOF3- anion has been synthesized as its Cs + and N(CH3)4+ salts and structurally characterized in the solid state by low-temperature Raman spectroscopy and quantum-chemical calculations. Vibrational frequency assignments for [Cs][XeOF3] and [N(CH3) 4][XeOF3] were aided by 18O enrichment. The calculated anion geometry is based on a square planar AX3YE 2 valence-shell electron-pair repulsion arrangement with the longest Xe-F bond trans to the oxygen atom. The F-Xe-F angle is bent away from the oxygen atom to accommodate the greater spatial requirement of the oxygen double bond domain. The experimental vibrational frequencies and trends in their isotopic shifts are reproduced by the calculated gas-phase frequencies at several levels of theory. The XeOF3- anion of the Cs + salt is fluorine-bridged in the solid state, whereas the anion of the N(CH3)4+ salt has been shown to best approximate the gas-phase anion. Although [Cs][XeOF3] and [N(CH 3)4][XeOF3] are shock-sensitive explosives, the decomposition pathways for the anions have been inferred from their decomposition products at 20°C. The latter consist of XeF2, [Cs][XeO2F3], and [N(CH3)4][F]. Enthalpies and Gibbs free energies of reaction obtained from Born-Fajans-Haber thermochemical cycles support the proposed decomposition pathways and show that both disproportionation to XeF2, [Cs][XeO2F3], and CsF and reduction to XeF2, CsF, and O2 are favorable for [Cs][XeOF3], while only reduction to XeF2 accompanied by [N(CH3)4][F] and O2 formation are favorable for [N(CH3)4][XeOF3]. In all cases, the decomposition pathways are dominated by the lattice enthalpies of the products.
- Brock, David S.,Mercier, Helene P. A.,Schrobilgen, Gary J.
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p. 10935 - 10943
(2010/09/16)
-
- Effect of mechanical activation on structure and thermal decomposition of aluminum sulfate
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The thermal decompositions of both non-activated and mechanically activated aluminum sulfates were studied by thermogravimetry (TG). The structural disorder, the specific surface area (SSA) and the morphology of mechanically activated aluminum sulfates we
- Ghasri-Khouzani,Meratian,Panjepour
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p. 535 - 539
(2009/06/30)
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- Stages of thermal decomposition of sodium oxo-salts of sulphur
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Thermal behaviour of sodium oxo-salts of sulphur: Na2SO 4, Na2S2O7, Na2S 2O6, Na2SO3, Na2S 2O5, Na2S
- Jaszczak-Figiel, Beata,Gontarz
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p. 147 - 154
(2009/05/06)
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- Photochemistry of SO2/CI2/O2 gas mixtures: Synthesis of the new peroxide CISO2OOSO2CI
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Photochemically induced gas-phase reactions of CI2/SO 2/O2 mixtures at -78 °C have been investigated on a preparative scale. The sulfuryl chlorides CISO2(OSO2) nCI, n = 0,1, or 2, along wit
- Romano, Rosana M.,Vedova, Carlos O.Della,Beckers, Helmut,Willner, Helge
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p. 1906 - 1910
(2009/07/18)
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- Probing the reactivity of the potent AgF2 oxidizer. Part 2: Inorganic compounds
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The reactivity of AgIIF2 towards forty two inorganic compounds containing oxo- and chloro- ligands, has been investigated. Five families of compounds were studied: (i) binary oxides of metals and nonmetals, (ii) ternary salts of inor
- Malinowski, Przemyslaw,Mazej, Zoran,Grochala, Wojciech
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p. 2608 - 2616
(2009/05/09)
-
- FTIR and computational studies of pure and water containing SO3 species in solid argon matrices
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The FT infrared spectrum in the 4000-400 cm-1 range of SO3 vapors, matrix isolated in argon and in water doped argon solid layers, is reported. Vibrational bands are assigned to pure SO3 monomeric and polymeric species and to SO3?H2O complexes, on the basis of theoretical B3LYP and MP2 calculations employing the aug-cc-pVTZ basis sets. The spectroscopic evidence suggests that in addition to the monomer, both the dimeric and the cyclic trimeric (SO3)n complexes are the only other SO3 forms present in the matrix. The spectra also indicate the presence of the 1:1 and the 1:2 SO3·H2O complexes as well as traces of H2S2O7 and water complexed H2SO4, but no evidence for a stable 2:1 SO3?H2O complex was found. The occurrence of the various species is discussed in the light of their calculated energies.
- Givan, Aharon,Loewenschuss, Aharon,Nielsen, Claus J.,Rozenberg, Mark
-
-
- Kinetics of sulfur oxide, sulfur fluoride, and sulfur oxyfluoride anions with atomic species at 298 and 500 K
-
The rate constants and product-ion branching ratios for the reactions of sulfur dioxide (SO2-), sulfur fluoride (SF n-), and sulfur oxyfluoride anions (SOxF y-) with H, H2, N, N2, NO, and O have been measured in a selected-ion flow tube (SIFT). H atoms were generated through a microwave discharge on a H2/He mixture, whereas O atoms were created via N atoms titrated with NO, where the N had been created by a microwave discharge on N2. None of the ions reacted with H 2, N2 or NO; thus, the rate constants are -12 cm3 s-1. SOxFy - ions react with H by only fluorine-atom abstraction to form HF at 298 and 500 K. Successive F-atom removal does not occur at either temperature, and the rate constants show no temperature dependence over this limited range. SO2- and F- undergo associative detachment with H to form a neutral molecule and an electron. Theoretical calculations of the structures and energetics of HSO2- isomers were performed and showed that structural differences between the ionic and neutral HSO 2 species can account for at least part of the reactivity limitations in the SO2- + H reaction. All of the SOxF y- ions react with O; however, only SO2 - reacts with both N and O. SOxFy- reactions with N (SO2- excluded) have a rate constant limit of -11 cm3 s-1. The rate constants for the SOxFy- reactions with H and O are ≤25% of the collision rate constant, as seen previously in the reactions of these ions with O3, consistent with a kinetic bottleneck limiting the reactivity. The only exceptions are the reactions of SO2 - with N and O, which are much more efficient. Three pathways were observed with O atoms: F-atom exchange in the reactant ion, F- exchange in the reactant ion, and charge transfer to the O atom. No associative detachment was observed in the N- and O-atom reactions.
- Midey, Anthony J.,Viggian
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p. 1852 - 1859
(2008/10/09)
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- Phase ratios in the K2O-V2O4-SO 3 system at high sulfur trioxide concentrations
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Phase ratios in the three-component oxide system K2O-V 2O4-SO3 in the region of the sulfur trioxide concentrations corresponding to its concentrations in the active component of vanadium catalysts for SO2/
- Krasil'nikov
-
p. 258 - 262
(2008/10/09)
-
- GaAs thermal oxidation in the presence of titanyl sulfate
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The kinetics of GaAs thermal oxidation in oxygen in the presence of titanyl sulfate was studied. Titanium and sulfur oxides resulting from the decomposition of the activator are involved in the process and accelerate it, especially at low temperatures. The resulting layers incorporate titanium and sulfur. Copyright
- Mittova, I. Ya,Lavrushina,Lopatin,Pinyaeva,Tibilova
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p. 685 - 688
(2008/10/09)
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- The effect of metal oxide additives (WO3, MoO3, V2O5, Ga2O3) on the oxidation of NO and SO2 over Pt/Al2O3 and Pt/BaO/Al2O3 catalysts
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Using NOx storage catalyst can overcome the problem with exhausts from diesel and lean burn engines, which contains a large surplus of oxygen that prevents effective reduction of NOx. The effect of metal oxide additives on enhancing NO oxidation and/or suppressing SO2 oxidation in alumina supported Pt catalysts was studied. In the absence of SO2, WO3/Pt/Al2O3 and MoO3/Pt/Al2O3 promoted the highest NO oxidation. In the presence of SO2, the NO oxidation activity was decreased for all catalysts. The decrease in NO oxidation activity due to SO2 exposure was highest for the Pt/Al2O3 and the Ga2O3/Pt/Al2O3 catalysts followed by WO3/Pt/Al2O3 and V2O5/Pt/Al2O3 catalysts and finally MoO3/Pt/Al2O3 catalyst. The MoO3/Pt/Al2O3 catalyst was the most efficient catalyst in enhancing the NO oxidation while suppressing the SO2 oxidation. For all catalysts, SO2 oxidation was promoted in the presence of NO in the reaction gas mixture Pt/BaO/Al2O3 and Pt/BaO/MoO3/Al2O3 catalysts showed equal NOx storage capacity in the sulfur free cycles. When SO2 was included in the reaction gas mixture, the NOx storage capacity declined faster for the Pt/BaO/MoO3/Al2O3 catalyst than for the Pt/BaO/Al2O3 catalyst, due to sulfur poisoning which resulted in a faster decrease in the regeneration capacity during rich periods.
- Dawody, Jazaer,Skoglundh, Magnus,Fridell, Erik
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p. 215 - 225
(2008/10/08)
-
- Isomers of OCS2: IR absorption spectra of OSCS and O(CS 2) in solid Ar
-
Irradiation of an Ar matrix sample containing O3 and CS 2 with a KrF excimer laser at 248 nm yielded new lines at 1402.1 (1404.7), 1056.2 (1052.7), and 622.3 (620.5) cm-1; numbers in parentheses correspond to species in a minor matrix site. Secondary photolysis at 308 nm diminished these lines and produced mainly OCS and SO2. Annealing of this matrix to 30 K yielded a second set of new lines at 1824.7 and 617.8 cm-1. The first set of lines are assigned to CS stretching, O-S stretching, and S-C stretching modes of carbon disulfide S-oxide, OSCS; and the second set of lines are assigned to CO stretching and OCS bending modes of dithiiranone, O(CS2), respectively, based on results of 34S- and 18O-isotopic experiments and quantum-chemical calculations. These calculations using density-functional theory (B3LYP/aug-cc-pVTZ) predict four stable isomers of OCS2: O(CS 2), SSCO, OSCS, and SOCS, listed in order of increasing energy. According to calculations, O(CS2) has a cyclic CS2 moiety and is the most stable isomer of OCS2. OSCS is planar, with bond angles OSC?111.9° and SCS?177.3°; it is less stable than SSCO and O(CS2) by ~102 and 154 kJ mol-1, respectively, and more stable than SOCS by ~26 kJ mol-1. Calculated vibrational wave numbers, IR intensities, 34S- and 18O-isotopic shifts for OSCS and O(CS2) fit satisfactorily with experimental results.
- Lo, Wen-Jui,Chen, Hui-Fen,Chou, Po-Han,Lee, Yuan-Pern
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p. 12371 - 12378
(2008/01/27)
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- Characterisation of the oxidation products of pyrite by thermogravimetric and evolved gas analysis
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Museum specimens of pyrite are known to undergo oxidation even during storage. Characterisation of the oxidation products is however not always simple due to amorphous character and varying degrees of hydration of the oxidation products, This paper presen
- Thomas,Hirschausen,White,Guerbois,Ray
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p. 769 - 776
(2008/10/08)
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- Adsorption and reaction of sulfur dioxide with Cu(110) and Cu(110)-p(2×1)-O
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Adsorption and reaction of sulfur dioxide with Cu(110)-p(2×1)-O were discussed. On the Cu(110)-p(2×1)-O surface, the nucleation and growth of the sulfite structures at p(2×1-O island boundaries was apparently accompanied by a structural relaxation. The fo
- Alemozafar, Ali R.,Guo, Xing-Cai,Madix, Robert J.
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p. 4698 - 4706
(2007/10/03)
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- Synthesis, crystal structure, and thermal decomposition of La(CH3SO3)3 · 2 H2O
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La(CH3SO3)3 · 2 H2O was prepared by the reaction of La2O3 with CH3SO3H. According to the X-ray single crystal determination, the compound crystallizes with triclinic symmetry (P1, Z = 2, a = 524.99(8), b = 1015.3(2), c = 1298.0(2) pm, α = 98.62(2)°, β = 91.12(2)°, γ = 104.61(2)°, Rall = 0.0405) and contains ninefold coordinate La3+ ions. The coordination polyhedra are tricapped trigonal prisms which are connected by CH3SO3- ions to double chains. These are linked via hydrogen bonding only. The thermal decomposition of La(CH3SO3)3 · 2 H2O was investigated by means of temperature dependent X-ray powder diffraction and DSC/TG/EGA methods. The compound dehydrates in a first step around 120°C to give the anhydrous methanesulfonate which decomposes finally yielding La2O2S2. According to the powder diffraction results the anhydrous methane sulfonate La(CH3SO3)3 crystallizes with a hexagonal structure (P63/m, a = 998.26(6), c = 597.97(6) pm) which has been found for the respective perchlorate, hydrogensulfate, and amidosulfate previously. WILEY-VCH Verlag GmbH, 2001.
- Wickleder, Mathias S.
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p. 1675 - 1681
(2008/10/08)
-
- Measurement of the rate constants for the reactions of the IO? radical with sulfur-containing compounds H2S, (CH3)2S, and SO2
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The reactions of iodine monoxide (IO?) with sulfur-containing compounds, which are important for the atmospheric chemistry, are studied. An attempt is made to distinguish between the heterogeneous and homogeneous reaction pathways. It is shown
- Larin,Messineva,Spasskii,Trofimova,Turkin
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p. 437 - 443
(2008/10/08)
-
- Reactions of FeVO4 with Sodium Salts
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The mechanisms of reactions of the sodium salts Na2SO4, NaCl, Na2CO3, and NaNO3 with iron orthovanadate FeVO4 in air is studied by X-ray, DTA, and thermodynamic analyses.
- Fotiev,Danilov,Surat
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p. 972 - 976
(2008/10/08)
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- (NH4)0.67Na0.33[VO2(SO 4)(H2O)2]: Preparation and Properties
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Formation conditions and properties of a new vanadium(V) compound of the composition (NH4)0.67Na0.33[VO2(SO 4)(H2O)2] were examined. This compound is a structural and chemical analogue of the previously prepared compounds M0.67Na0.33[VO2(SO4)(H 2O)n] (M = K, Rb, or Cs; n = 2). On heating in air, (NH4)0.67Na0.33[VO2(SO 4)(H2O)2] is decomposed without forming the corresponding anhydrous compound and completely loses SO3 at 900°C to yield the well-known polyvanadate NaV3O8.
- Krasil'nikov,Galaktionov
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p. 819 - 823
(2008/10/08)
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- Synthesis, identification and thermal decomposition of double sulfates of La, Ce, Pr or Nd with ethanolammonium
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On evaporation at room temperature of an aqueous reaction mixture of Ln(III) sulfate and ethanolammonium sulfate in a molar ratio higher than 1:16, crystal products with a waxy feel were obtained. They were identified by means of the X-ray powder diffraction patterns and it was concluded that they are isostructural. The results of elemental analysis and the mass losses by TG analysis indicated the formation of double sulfates with general formula: (HOCH2CH2NH3)4Ln2(SO4)5·4.5H2O (Ln = La, Ce, Pr or Nd). Their thermal decompositions in static atmosphere in the temperature range from ambient up to 1173 K took place in a similar way, and mainly Ln2O2SO4 was obtained as final product. The exception was the Ce compound, which decomposed to CeO2. The double sulfates decomposed in many not well-differentiated steps. From the mass losses occurring during thermal decomposition, the mode of thermal decomposition was presumed. The X-ray powder diffraction patterns of Ln2O2SO4(Ln = La, Pr and Nd) show that they are also isostructural.
- Jordanovska,Trojko
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p. 785 - 793
(2008/10/08)
-