1033995-63-9Relevant academic research and scientific papers
REACTIONS OF METAL-CLUSTER CARBONYLS IN PILLARED CLAY GALLERIES: SURFACE COORDINATION CHEMISTRY AND FISCHER-TROPSCH CATALYSIS.
Giannelis,Rightor,Pinnavaia
, p. 3880 - 3885 (1988)
A new method is reported for introducing transition-metal centers in the galleries of a thermally stable pillared clay. The authors approach focuses on the reactions of metal-cluster carbonyl complexes with protons and surface hydroxyl groups of an alumina pillared montmorillonite, henceforth abbreviated APM. The surface chemistry of tri- and tetranuclear ruthenium, osmium, and iridium carbonyls is examined in comparison to the chemistry of these species on the surfaces of bulk oxides. Also, we report the formation of supported ruthenium aggregates in the intracrystalline environment of the clay and describe the Fischer-Tropsch (FT) product selectivity of this new catalyst system.
Preferential oxidation of CO in H2 by aqueous polyoxometalates over metal catalysts
Kim, Won Bae,Voitl, Tobias,Rodriguez-Rivera, Gabriel J.,Evans, Steven T.,Dumesic, James A.
, p. 778 - 782 (2005)
Stream cleaning: CO in CO/H2 mixtures is oxidized preferentially at room temperature with an aqueous polyoxometalate (POM) solution over gold catalysts (see scheme). The rate of H2 oxidation is slow and is inhibited by CO. This process can be used to remove CO efficiently from H 2 gas streams. The solution containing protons and reduced POM can be used to produce electrical energy at a fuel-cell anode through re-oxidation of the reduced POM.
Temperature dependence of adlayers on Pt(1 1 1) and Au(1 1 1) in a sulfuric acid solution studied by in situ IRAS
Shingaya,Ito
, p. 425 - 430 (2001)
Temperature dependence studies of adsorption of sulfuric acid species on Pt(111) and Au(111) electrodes were carried out using in situ infrared reflection absorption spectroscopy. A temperature-dependent shift of the interconversion potential between HSO4-/H3O+ and H2SO4 on a Pt(111) electrode was observed. A temperature-dependent frequency shift of the absorption bands of HSO4- was also observed on both Pt(111) and Au(111) electrodes in the potential region where a √3×√7 structure evolved. Modelling experiments in ultrahigh vacuum revealed that ordering of the overlayer water molecules played an important role in the frequency of the absorption bands of HSO4-.
Chemistry and Structure of the CH3O2(+) Product of the O2(+) + CH4 Reaction
Doren, J. M. Van,Barlow, S. E.,DePuy, C. H.,Bierbaum, V. M.,Dotan, I.,Ferguson, E. E.
, p. 2772 - 2777 (1986)
The CH3O2(+) product ion of the thermal energy reaction between O2(+) and CH4 has been studied in reaction with a number of neutral molecules.The reactivity pattern demonstrates very convincingly that the structure of the ion is methylene hydroperoxy cation, CH2OOH(+), in contrast to previous reports that the ion is protonated formic acid, HC(OH)2(+) or HC(O)OH2(+).From these and other data the heat of formation of this ion is determined to be between 182 and 188 kcal/mol.
Electrochemical reduction of bisulfite in mildly acidic buffers: Kinetics of sulfur dioxide - Bisulfite interconversion
Tolmachev, Yuriy V.,Scherson, Daniel A.
, p. 1572 - 1578 (1999)
The reduction of bisulfite on a bismuth rotating disk electrode (RDE) was studied in aqueous buffered electrolytes over the pH range 3-6. Clearly defined limiting currents were observed in all solutions examined; however, their magnitudes were not only smaller than those expected for a process limited by the diffusion of bisulfite from the bulk solution, but were also found to decrease as the media became less acidic. This behavior was attributed to a preceding homogeneous process that generates sulfur dioxide, the actual electroactive species. UV - visible absorption - reflection spectroscopy measurements at a RDE showed that in the potential region in which such limiting currents are observed, dithionite is produced with 100% faradaic efficiency, Results of rotation rate staircase scan amperometric RDE experiments were found to be consistent with the conversion of bisulfite into SO2 proceeding via a general acid catalysis mechanism, and allowed values for the rate constants for the following reactions to be determined: SO2 + H2O → HSO3- + H3O+, kb = (1.6 ± 0.2) 107 s-1; HSO3- + H3O → SO2 + H2O, kfH = (1.2 ± 0.15) 109 M-1 s-1; HSO3- + CH3COOH → SO2 + H2O + CH3COO-, kfHA = (1.7 ± 0.5) 104 M-1 s-1. On this basis, and assuming diffusion-controlled rates for proton transfer from strong acids to oxygen bases, a more detailed mechanism involving formation of sulfurous acid as an intermediate is discussed and some thermodynamic and kinetic properties of the latter are estimated.
Ion-Molecule Reactions Involving H3O+, H2O+, and OH+ at Thermal Energy
Shul, R. J.,Passarella, R.,DiFazio, L. T.,Keesee, R. G.,Castleman, A. W.
, p. 4947 - 4951 (1988)
The rate coefficients for a variety of reactions involving OH+, H2O+, and H3O+ with CS2, H2S, SO2, NO, NO2, N2O, N2, O2, CH4, CO2, CO, NH3, and H2 are obtained with a selected ion flow tube.The product channels include proton transfer, charge transfer, atom abstraction, and association.Most of the reaction rates are fast and have high reaction efficiencies.Reaction of OH+ with NO2 is found to produce both NO2+ and NO+; even though both reaction channels are also exothermic with H2O+, only NO2+ is produced.H3O+ is found to undergo association reactions with SO2 and N2O and H2O+ does so with CO2 and N2O.The reaction of H2O+ with N2O also involves a second-order process in addition to the association pathway.
Orthorhombic B2CN crystal synthesized by high pressure and temperature
He,Tian,Yu,Wang,Liu,Guo,Li,Jia,Chen,Zou,Yanagisawa
, p. 431 - 436 (2001)
B0.54C0.28N0.18 precursor powder with turbostratic structure was prepared by using melamine and boric acid. The precursor was transformed into orthorhombic B2CN under definite high pressure and temperature conditions. The composition of the orthorhombic B2CN powder is B0.47C0.23N0.30. Its lattice parameters are a=0.4776 nm, b=0.4585 nm and c=0.3629 nm. A strong absorption band from 1088 to 1385cm-1 of orthorhombic B2CN was observed by infrared measurement. In the photoluminescence (PL) spectrum of orthorhombic B2CN powder measured at room temperature, a broad peak corresponding to its band-edge emission centers at 374 nm.
Thermal decomposition of hydrogen peroxide in the presence of sulfuric acid
Wu,Chen,Cheng,Lee,Shu
, p. 115 - 120 (2008)
Hydrogen peroxide (H2O2) is popularly employed as a reaction reagent in cleaning processes for the chemical industry and semiconductor plants. By using differential scanning calorimetry (DSC) and vent sizing package 2 (VSP2), this study focused on the thermal decomposition reaction of H2O2 mixed with sulfuric acid (H 2SO4) with low (0.1, 0.5 and 1.0 N), and high concentrations of 96 mass%, respectively. Thermokinetic data, such as exothermic onset temperature (T 0), heat of decomposition (ΔH d), pressure rise rate (dP/dt), and self-heating rate (dT/dt), were obtained and assessed by the DSC and VSP2 experiments. From the thermal decomposition reaction on various concentrations of H2SO4, the experimental data of T 0, ΔH, dP/dt, and dT/dt were obtained. Comparisons of the reactivity for H2O2 and H2O2 mixed with H2SO4 (lower and higher concentrations) were evaluated to corroborate the decomposition reaction in these systems.
Interaction between the ion dipole and the ion-induced dipole in reactions of the polar ion ArH+3
Praxmarer, C.,Hansel, A.,Lindinger, W.
, p. 8884 - 8889 (1994)
The reactions of the highly polar ion ArH+3 with the nonpolar neutrals Xe, Kr, CH4, CO, NO, O2, and N2 and with the polar neutrals SO2, H2O, NH3, CH3I, and C2H5I have been investigated in a selected ion flow drift tube experiment at near thermal conditions.The rate coefficients obtained have typically 15percent-35percent larger values than the collisional limiting values kL and kADO obtained by the Langevin and ADO (average dipole orientation) theory, respectively.These data are explained on the basis of the interaction between the dipole of ArH+3 and the ion-induced dipole and the permenent dipole, respectively, of the neutral reactants.Rate coefficients for the reactions of H+3 with the above neutrals were also obtained for comparison, as well as the zero field mobility of ArH+3 in helium being (18.5+/-1.5) cm2/V s.The ion KrD+3 (KrH+3) was detected unambiguously for the first time.Its dissociation energy is larger than 0.29 eV which is the lower limit of the dissociation energy of ArH+3.
Kinetic study of the complex formation of boric and boronic acids with mono- and diprotonated ligands
Ito, Hideaki,Kono, Yoko,Machida, Akinori,Mitsumoto, Yoko,Omori, Kenji,Nakamura, Noriko,Kondo, Yuichi,Ishihara, Koji
, p. 28 - 36 (2003)
The complex formation reactions of boric and boronic acids (RB(OH)2: R=OH, n-Bu, Ph, and m-NO2Ph) with 4-isopropyltropolone (Hipt) and chromotropic acid (H2cht2-) have been studied kinetically at various pH. The reactions of H2ipt+ with boronic acids were faster than those of Hipt by a factor of 1.5-11, and fully deprotonated ipt- also reacted with m-NO2PhB(OH)2, but slower than Hipt. The tetrahedral m-NO2PhB(OH)3- ion did not react with Hipt. Reaction routes for the complexation of boric acid with chromotropic acid could not be specified because of the unexpected problem of proton ambiguity. Mechanism for the reactions of boronic acids with bidentate ligands was discussed in terms of rate determining chelate ring closure. It was concluded that at least one proton is necessary for the OH- in the tetrahedral intermediates to be eliminated smoothly as water, and a doubly hydrogen-bonded intermediate was proposed for the reactions with diprotic ligands.
