- Bi-functional RuO2-Co3O4 core-shell nanofibers as a multi-component one-dimensional water oxidation catalyst
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The core-shell structure of RuO2-Co3O4 fibers comprising the inner region of highly conductive RuO2 and the outer region of catalytic Co3O4 provided a fast and effective transport pathway for holes to O2-evolving sites, leading to a highly efficient water oxidation performance.
- Ko, Jong Wan,Ryu, Won-Hee,Kim, Il-Doo,Park, Chan Beum
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- Hydrogen sulfates with disordered hydrogen atoms - Synthesis and structure of Li[H(HSO4)2](H2SO4)2 and refinement of the structure of α-NaHSO4
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The structure of Li[H(HSO4)2](H2SO4)2 has been determined for the first time whereas the structure of α-NaHSO4 has been refined, so that direct determination of the hydrogen positions was possible. Both compounds crystallize triclinic in the space group P1 with the lattice constants a = 6.708(2), b = 6.995(1), c = 7.114(1) A, α = 75.53(1), β = 84.09(2) and γ = 87.57(2)° (Z = 4) for α-NaHSO4 and a = 4.915(1), b = 7.313(1), c = 8.346(2) A, α = 82.42(3), β = 86.10(3) and γ = 80.93(3)° (Z = 1) for Li[H(HSO4)2](H2SO4),. In both compounds there are disordered hydrogen positions. In the structure of α-NaHSO4 there are two crystallographically different HSO4- tetrahedra and two different coordinated Na atoms. The system of hydrogen bonds can be described by chains in [0-11] direction. The disordering of the H atoms reduces the differences between the S-O and S-OH distances (1.45 and 1.50 A) while in the ordered HSO4 unit regular bond lengths are observed (1.45 und 1,57 A). In the structure of Li[H(HSO4)2](H2SO4)2 there are two crystallographically different SO4-tetrahedra. The first one belongs to the [H(HSO4)2]- unit while the second one represents H2SO4 molecules. The H atom which is located nearby the symmetry centre and connects two HSO4 units by a short O...O distance of 2.44 A. Li is located on a symmetry centre and is slightly distorted octahedrally coordinated by oxygen atoms of six different SO4 tetrahedra. The system of hydrogen bonds can be regarded as consisting of double layers parallel to the xy-plane. Johann Ambrosius Barth 1996.
- Werner,Trojanov,Worzala,Kemnitz
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- Phase transition between two anhydrous modifications of NaHSO4 mediated by heat and water
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The phase transition between the two anhydrous modifications of NaHSO4 (α and β) was studied using Raman spectroscopy and differential scanning calorimetry. These measurements indicate that β-NaHSO4 is a metastable phase and readily undergoes phase transition to thermodynamically stable α-NaHSO4 with an exothermic enthalpy change of 3.5 kJ/mol. Both thermal (temperatures >434 K) and chemical (exposure to H2O) pathways were identified for this transition. The transition is irreversible, and α-NaHSO4 is an intermediate phase between β-NaHSO4 and NaHSO4·H2O. The possible mechanism of the phase transition is discussed.
- Zangmeister, Christopher D.,Pemberton, Jeanne E.
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- Kinetics of the autoxidation of sulfur(iv) co-catalyzed by peroxodisulfate and silver(i) ions
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The kinetics and mechanism of the reaction between dissolved oxygen and sulfur(iv) was studied in aqueous acidic medium using co-catalysts peroxodisulfate and silver(i) ions. The presence of both catalysts was required to observe measurable rates in the studied process. The reaction rate was determined through following the UV-absorption of hydrated sulfur dioxide, and the trends were determined as a function of pH, reactant and catalyst concentrations. Individual kinetic curves under conditions where dissolved oxygen was the limiting reagent were close to zeroth-order. A chain mechanism with four chain carriers, sulfite, sulfate, peroxomonosulfate ion radical and silver(ii) ion, is proposed to interpret all the kinetic and stoichiometric findings, and an explicit formula was obtained for the rate law. The role of the co-catalysts is to produce chain carriers, whereas silver(i) and silver(ii) ions also participate in chain propagation steps. Further supporting evidence for the proposed mechanism was gained in laser flash photolysis studies, which showed that sulfate ion radical reacts quite rapidly with silver(i) ion.
- Doka, Eva,Lente, Gabor,Fabian, Istvan
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- Method for comprehensively utilizing dehydrated dilute sulphuric acid and byproduct sodium chloride and producing byproduct sodium hydrogen sulfate
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The invention provides a method for comprehensively utilizing dehydrated dilute sulphuric acid and byproduct sodium chloride and producing byproduct sodium hydrogen sulfate. The method comprise the following steps: feeding dehydrated dilute sulphuric acid and byproduct sodium chloride in a production process for producing glyphosate by virtue of a glycine method into a reaction kettle, and carrying out heat preservation reaction; cooling a gas phase to 28-33 DEG C by virtue of a condenser, and introducing the gas phase into a four-stage hydrochloric acid absorption tower in a dimethyl phosphite production process; and carrying out filtration, cooling crystallization, centrifugal separation and drying on reaction liquid, so as to obtain the finished product sodium hydrogen sulfate. By virtue of the method, the treatment problem of dehydrated dilute sulphuric acid and byproduct sodium chloride is solved, and the resource comprehensive reutilization of byproducts including dilute sulphuric acid and sodium chloride in the production of glyphosate is realized.
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Paragraph 0012
(2017/04/03)
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- Synthesis of Ammonia Borane Nanoparticles and the Diammoniate of Diborane by Direct Combination of Diborane and Ammonia
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Pure nanoparticle ammonia borane (NH3BH3, AB) was first prepared through a solvent-free, ambient-temperature gas-phase combination of B2H6 with NH3. The prepared AB nanoparticle exhibits improved dehydrogenation behavior giving 13.6 wt. % H2 at the temperature range of 80-175°C without severe foaming. Ammonia diborane (NH3BH2(μ-H)BH3, AaDB) is proposed as the intermediate in the reaction of B2H6 with NH3 based on theoretical studies. This method can also be used to prepare pure diammoniate of diborane ([H2B(NH3)2][BH4], DADB) by adjusting the ratio and concentration of B2H6 to NH3.
- Song, Yuanzhou,Ma, Nana,Ma, Xiaohua,Fang, Fang,Chen, Xuenian,Guo, Yanhui
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supporting information
p. 6228 - 6233
(2016/05/02)
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- Quantum yield measurements for the photocatalytic oxidation of Acid Orange 7 (AO7) and reduction of 2,6-dichlorindophenol (DCIP) on transparent TiO2 films of various thickness
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This work comprises the photoactivity assessment of transparent sol-gel TiO2 coatings of various thickness using two test systems. The initial rates of both photocatalytic reactions, namely the oxidative bleaching of Acid Orange 7 (AO7) and the reductive bleaching of 2,6-dichlorindophenol (DCIP) increase linearly with increasing titania film thickness as well as with increasing absorbed light flux. The latter work revealed quantum yields (QY) of 0.19% and 92% for the AO7 and DCIP test system, respectively. The low QY for the AO7 oxidation is due to the combination of a slow irreversible reduction of oxygen and also for the oxidation of AO7, thus favouring the high efficiency for electron-hole recombination that is typical for aqueous organic pollutants. In contrast, the very high QY for the photocatalysed reduction of DCIP is due to the presence of a vast excess of glycerol which traps the photogenerated holes efficiently and so allow time for the slower reduction of dye to take place. Furthermore, the oxidation of glycerol results in the generation of highly reducing R-hydroxyalkyl radicals that are able to also reduce DCIP. As a consequence of this 'current doubling' effect, the observed QY (92%) is much higher than the apparent theoretical value of 50%.
- Krysa,Baudys,Mills
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p. 132 - 137
(2015/02/19)
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- NO LAXATION, LOW FLATULENCE BULKING SYSTEM
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A no-laxation, low flatulence bulking system and a method for preparation of same is disclosed. Gelatin, pectins and gellan gum are combined to form a dry-blended mixture. A second set of ingredients comprising at least erithritol is combined. A first liquid mixture comprising modified polydextrose and water is formed. The first dry-blended mixture is added to the first liquid mixture, forming a first mix. The second dry-blended mixture is added to the first mix, dimethicone is added, and the combination is heated to a first predetermined temperature. The heat is then reduced to a second predetermined temperature, and a second liquid mixture comprised of at least one acid and water is added. The second liquid mixture also may preferably include fruit concentrate, flavor, color and/or sucralose. The resultant solution is then preferably stirred constantly and held in a kettle or mixing tank for panning or molding as desired.
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- PHOSPHONIUM IONIC LIQUIDS AS RECYCLABLE SOLVENTS FOR SOLUTION PHASE CHEMISTRY
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This application relates to the use of phosphonium-based ionic liquids as recyclable solvents for solution phase chemistry. The ionic liquids may be used, for example, as solvents for reactions involving Grignard reagents, hydridic reagents, metallic and non-metallic reducing agents, and strong bases, including nucleophilic carbenes and Wittig reagents. In one embodiment the invention may comprise homogeneous mixtures of strong bases/nucleophiles/reducing agents and tetrahydrocarbylphosphonium salt ionic liquids. The invention also relates to chemical processes that may proceed in either minimally flammable solvent, or a complete absence of flammable solvent, including systems containing strong reducing agents such as alkali and alkaline metals or metal and non-metal hydrides. Methods for generating anions and nucleophililic carbenes (imidazol-2-ylidenes) (and complexes derived from them) in phosphonium-based ionic liquids are also described. The invention demonstrates the feasibility of using phosphonium-based ionic liquids as a reliable reaction media for a wide variety of basic reagents. The problems associated with C-H activation in imidazolium-based ionic liquids by highly reactive bases are not observed for phosphonium-based ionic liquids.
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Page/Page column 29-30
(2010/02/15)
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- Raman spectroscopy and atomic force microscopy of the reaction of sulfuric acid with sodium chloride
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The reaction of NaCl with H2SO4 is investigated using Raman spectroscopy, atomic force microscopy (AFM), and gravimetric analysis. Raman spectra are consistent with the formation of NaHSO4 with no evidence for Na2SO4. The spectra indicate that the phase of NaHSO4 varies with the amount of H2O in the H2SO4. At low H2O concentrations, the reaction produces anhydrous β-NaHSO4, which undergoes a phase change to anhydrous α-NaHSO4 over the course of 18 h. At higher H2O concentrations, anhydrous α-NaHSO4 is formed with small amounts of NaHSO4·H2O. AFM measurements on NaCl (100) show the formation of two distinct types of NaHSO4 structures consistent in shape with α-NaHSO4 and β-NaHSO4. The β-NaHSO4 structures are mobile and move along the NaCl (110) plane until they encounter existing stationary α-NaHSO4 structures whereupon the two forms coalescence to form larger α-NaHSO4 structures. Gravimetry was used to determine the amount of HCl evolved upon exposure to aqueous H2SO4 solutions modeling atmospheric aerosols. At low H2SO4 concentrations, a large percentage of the HCl formed remains dissolved in the H2O. These results indicate that for conditions simulating relative humidities above 40%, the fraction of HCl released from this reaction may be as low as 0.40 ± 0.11.
- Zangmeister,Pemberton
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p. 12289 - 12296
(2007/10/03)
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- Process of preparing N-substituted aldonamides having improved color and color stability
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A process of preparing N-substituted aldonamides, the process including the steps of mixing and reacting an aldonolactone and an amine in an organic polar solvent, in the presence of an antioxidant and a reducing agent. The aldonamides have improved color; the discoloration or browning of the aldonamides upon storage or elevated temperature processing is eliminated or substantially minimized.
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