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1.
Experimental results on the interaction of Cr atoms with various oxygen-containing molecules (NO, N2O, CO2, NO2, and SO2) at high temperatures (>1000 K) are presented. It is demonstrated that activation barrier for spin-forbidden reactions is
higher, all other things being equal. For the reaction of Cr atoms with N2O, an interpolated temperature dependence of the rate constant, based on the high-temperature measurements conducted in the
present work and the published low-temperature data, is proposed. 相似文献
2.
Explosive characteristics of polybasic explosive mixture gas are systematically researched. Over 28000 experimental data have been obtained from 1278 effective experiments. The paper probes into the concentration explosive limits and the container factors of polybasic explosive mixture gas which contains H2, CH4 and CO. It has worked out the sufficient and necessary condition for branch-chain explosion and the unified expression of the probability of the heterogeneous chain termination. Experiments indicate that the concentration explosive limits of polybasic explosive mixture gas (H2, CH4, CO) relate to many factors. They enlarge with the augmentability of the container (linear size, geometric shape, and flame spread direction). This will be of great significance to guiding the revision of related industrial safety targets, reclaiming and reusing related industrial tail gas and waste gas, taking precautions against the explosion hazard of mixture gas in correlated industry and mines, and applying the br 相似文献
3.
L. Li X. Wang J. Shen L. Zhou T. Zhang 《Journal of Thermal Analysis and Calorimetry》2005,82(1):103-107
Adsorption microcalorimetry has been employed to study the interaction of ethylene with the reduced and oxidized Pt-Ag/SiO2catalysts with different Ag contents to elucidate the modified effect of Ag towards the hydrocarbon processing on platinum
catalysts. In addition, microcalorimetric adsorption of H2, O2, CO and FTIR of CO adsorption were conducted to investigate the influence of Ag on the surface structure of Pt catalyst.
It is found from the microcalorimetric results of H2and O2adsorption that the addition of Ag to Pt/SiO2leads to the enrichment of Ag on the catalyst surface which decreases the size of Pt surface ensembles of Pt-Ag/SiO2catalysts. The microcalorimetry and FTIR of CO adsorption indicates that there still exist sites for linear and bridged CO
adsorption on the surface of platinum catalysts simultaneously although Ag was incorporated into Pt/SiO2. The ethylene microcalorimetric results show that the decrease of ensemble size of Pt surface sites suppresses the formation
of dissociative species (ethylidyne) upon the chemisorption of C2H4on Pt-Ag/SiO2. The differential heat vs. uptake plots for C2H4adsorption on the oxygen-preadsorbed Pt/SiO2and Pt-Ag/SiO2catalysts suggest that the incorporation of Ag to Pt/SiO2could decrease the ability for the oxidation of C2H4. 相似文献
4.
The incorporation of nanomaterials into electrochemical sensors is an attractive approach towards the improvement of the sensitivity of amperometry and also can provide improved sensor selectivity and stability. This review (with 137 references) details the current state of the art and new trends in nanomaterial-based electrochemical sensing of hydrogen peroxide (H2O2), hydrogen sulfide (H2S) and nitric oxide (NO) in cells or released by cells. The article starts with a discussion of the significance of the three analytes, and this is followed by three sections that summarize the electrochemical detection schemes for H2O2, H2S and NO. Each section first summarizes the respective physiological roles, and then reviews electrochemical sensors based on the use of carbon nanomaterials, noble metal nanomaterials, metal oxide nanomaterials, and layered doubled hydroxides. The materials are compiled in three tables along with figures of merit for the various sensors. 相似文献
5.
M. M. Gafurov K. Sh. Rabadanov V. D. Prisyazhnyi D. O. Tret’yakov M. I. Gorobets S. A. Kirillov M. B. Ataev M. M. Kakagasanov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(9):1499-1504
The phase diagrams, isotherms of the electrical conductivity, Raman spectra, and time correlation functions of vibrational
dephasing are studied for the LiN(CF3SO2)2-(CH3)2SO2 system, which is promising for use as an electrolyte in medium-temperature lithium-ion batteries. The phase diagram of this
system contains a broad supercooled region. It is shown that the concentration dependences of the electrical conductivity
are typical for solutions of strong electrolytes. The Raman spectra and the time correlation functions of vibrational dephasing
for the anion and the solvent indicate that in the supercooling range, cations are weakly solvated by solvent molecules and
form ion pairs. 相似文献
6.
Anna Migdał-Mikuli Joanna Hetmańczyk Ł. Hetmańczyk 《Journal of Thermal Analysis and Calorimetry》2007,89(2):499-503
Motor gasoline must present
characteristics that guarantee its quality and the good performance of internal
combustion engines without harming the environment. The contamination of gasoline
by solvents can seriously adulterate its physical-chemical properties and
affect its volatility and detonation capacity. To investigate organic solvent
adulteration in gasoline samples, thermal analysis technique (TG/DTG) can
be used as an auxiliary tool in the study of the thermal behavior of liquid
fuels, as demonstrated by the present work involving a comparative analysis
of kerosene-free and doped gasoline. 相似文献
7.
8.
Phase equilibria in the Na, K∥SO4, CO3, F-H2O system at 25°C are studied using the translation technique. Twenty four divariant fields, 22 univariant curves, and seven invariant points are found in the system. The complete phase diagram (the phase complex) of the system is designed on the basis of these data. 相似文献
9.
Yu. V. Kokunov Yu. E. Gorbunova V. V. Kovalev 《Russian Journal of Coordination Chemistry》2009,35(9):643-647
The complex [Co(2-Me-Pyz)2(H2O)4](NO3)2 is synthesized and its structure is determined. The crystals are monoclinic: space group P21/n, a = 10.685(2) Å, b = 6.837(1), c = 12.515(3) Å, β = 91.84(3)°, V = 913.8(3) Å3, ρcalcd = 1.042 g/cm 3, Z = 2. The Co2+ ion (in the inversion center) is coordinated at the vertices of the distorted octahedron by two nitrogen atoms of methylpyrazine and four oxygen atoms of the water molecules (Co(1)–N(1) 2.180(3), average Co(1)–O(w) 2.079(3) Å, angles at the Co atom 87.9(1)–92.1(1)°). Supramolecular pseudometallocycles are formed in the structure through the O(w)–H…N(1) hydrogen bonds between the coordinated H2O molecules and the terminal nitrogen atoms of the 2-methylpyrazine molecules. Their interaction results in the formation of supramolecular layers joined by the NO3 groups into a three-dimensional framework. 相似文献
10.
V. A. Matyshak A. N. Il’ichev O. N. Sil’chenkova V. A. Sadykov V. N. Korchaka 《Kinetics and Catalysis》2016,57(5):677-685
The adsorption of reactant mixtures is quantitatively and qualitatively different from the adsorption of the individual reactants. Thus, O2 is almost not adsorbed on ZrO2; however, a considerable concentration of molecular oxygen was detected among the products of desorption after the adsorption of a mixture of NO + O2 and the total amount of desorbed molecules was greater by a factor of 10 than their total amount after the individual adsorption of NO and O2. Among the qualitative differences is the formation of the O2- radical anion on the surface only upon the adsorption of the mixture of NO + O2. Similarly, the number of desorbed molecules upon the simultaneous adsorption of C3H6, NO, and O2 was much greater than that upon their individual adsorption; this is related to the formation of paramagnetic and nonparamagnetic NO2–hydrocarbon complexes on the surface, which contained the NO2 group and a hydrocarbon fragment. 相似文献
11.
I. A. Kirilenko 《Russian Journal of Inorganic Chemistry》2010,55(4):602-606
Glass formation boundaries in the Al2(SO4)3-Al(NO3)3-H2O system were determined. IR spectra were studied. Schemes of structural rearrangements within the boundaries of a second
glass formation region in the Al(NO3)3-H2O binary subsystem are suggested. A structure is suggested for glassy Al(NO3)3H2O. 相似文献
12.
One of the methods for the synthesis of peroxy-radical condensates is the condensation at liquid nitrogen temperature of an
H2+O2 mixture dissociated in an electrical discharge at low pressure. Peroxy-radical condensates are thought to contain substantial
quantities of higher hydrogen peroxides H2O3 and H2O4. The present work investigates the influence of experimental parameters on the synthesis of peroxy-radical condensates from
an H2+O2 mixture, analyses the relevant literature, and recommends the optimal experimental conditions for the synthesis. The synthesis
is carried out in a U-tube electrical discharge reactor (inner diameter ∼15 mm), immersed in liquid nitrogen, at rather low
pressure (0.5–1 Torr). The maximum conversion of initial O2 into higher hydrogen peroxides was observed at a composition of initial gas mixture of 66.7% H2 + 33.3% O2. 相似文献
13.
Sabri Cevik Bihter Şaşmaz Cengiz Yenikaya Ferdağ Çolak Musa Sari Orhan Büyükgüngör 《Russian Journal of Inorganic Chemistry》2010,55(4):494-500
The hydrothermal reaction of a mixture of V2O5, VCl3, 2,5-pyridinedicarboxylic acid and diluted H2SO4 for 68 h at 180°C gives a blue colored solution which yields prismatic blue crystals of IV 2 IV O2(SO4)2(H2O)6] (1) in 32% yield (based on V). Complex 1 was investigated by means of elemental analysis (C, H and S), TGA, FT-IR, manganometric titration, Single Crystal X-ray Diffraction Methods and also comparative antimicrobial activities. Crystal data for the compound: monoclinic space group P21/c and unit cell parameters are a = 7.3850(12) Å, b = 7.3990(7) Å, c = 12.229(2) Å, β = 108.976(12)° and Z = 2. Although structure of 1 as a natural mineral has been previously determined, this work covers new preparation method and full characterization of 1 along with comparison of antibacterial activity between 1 and the commercial vanadium(IV) oxide sulfate hydrate compounds, VOSO4 · xH2O (Riedel-de Haën and Alfa Aesar brand names). 1 was evaluated for the antimicrobial activity against gram-positive, gram-negative bacteria, yeasts and mould compared with the commercial VOSO4 · xH2O compounds. 1 showed weak activity against bacteria Bacillus cereus, Nocardia asteroides and yeast Candida albicans. A good antimicrobial activity was recorded against Cirtobacter freundii (15 mm). There are only a few reproducible well-defined vanadium(IV) starting materials to use for exploring the synthesis of new materials. VCl4, VO(acac)2, VOSO4 · xH2O and [V(IV)OSO4(H2O)4] · SO4 · [H2N(C2H4)2NH2] are common starting materials for such applications. In addition to these compounds, 1 can be used as an oxovanadium precursor. 相似文献
14.
Babasaheb P. Bandgar Vibhav S. Sadavarte Sampada V. Bettigeri 《Monatshefte für Chemie / Chemical Monthly》2002,133(3):345-348
Summary. Benzylic alcohols are selectively converted into their corresponding iodides using KI/H2SO4 supported on natural kaolinitic clay and microwaves.
Received August 20, 2001. Accepted (revised) September 18, 2001 相似文献
15.
The adsorption of small molecules NO, NH3 and H2O on V2O5/TiO2 catalysts is studied with the semiempirical SCF MO method MSINDO as pre-stage for the selective catalytic reduction of NO. The mixed catalyst is represented by hydrogen-terminated cluster models. The local arrangement of the cluster atoms is in accordance with available experimental information. Partial relaxation of cluster atoms near the adsorption sites is taken into account. Calculated adsorption energies are compared with experimental literature data. Rapid convergence of computed properties with cluster size is observed. A possible reaction mechanism for the catalytic reduction of NO with NH3 and O2 is outlined. 相似文献
16.
Z. Hong-Kun T. Cao Zh. Dao-Sen X. Wen-Lin W. Ya-Qong Q. Qi-Shu 《Journal of Thermal Analysis and Calorimetry》2007,89(2):531-536
The non-isothermal decomposition kinetics of 4Na2SO4·2H2O2·NaCl have been investigated by simultaneous TG-DSC in nitrogen atmosphere and in air. The decomposition processes undergo
a single step reaction. The multivariate nonlinear regression technique is used to distinguish kinetic model of 4Na2SO4·2H2O2·NaCl. Results indicate that the reaction type Cn can well describe the decomposition process, the decomposition mechanism
is n-dimensional autocatalysis. The kinetic parameters, n, A and E are obtained via multivariate nonlinear regression. The n
th-order with autocatalysis model is used to simulate the thermal decomposition of 4Na2SO4·2H2O2·NaCl under isothermal conditions at various temperatures. The flow rate of gas has little effect on the decomposition of
4Na2SO4·2H2O2·NaCl. 相似文献
17.
Isonicotinato cadmium(II) complex [Cd(C6H4NO2)2(H2O)4] has been synthesized by hydrothermal method and characterized by elemental analysis, electronic-spectra and thermogravimetric analysis. Density functional theory (DFT) method calculations of the structure, atomic charges distribution, electronic spectra, natural population analysis and the thermodynamic properties at different temperatures have been performed. The calculated results show the electronic transitions are mainly derived from the contribution of bands π → π* and the decomposition of the title compound should first occur at the bond of Cd—O, then at the bond of Cd—N, which agrees very well with the experimental data. 相似文献
18.
D. Popović G. Stupar J. Miladinović M. Todorović M. Zrilić 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(13):2349-2353
The solubility in the ternary system, aqueous mixture of CaSO4 and Na2SO4, at T = 298.15 K comprises five different salts: calcium sulfate dihydrate, mirabilite, thenardite, glauberite and labile salt.
Using the Extended Pitzer’s Ion Interaction model for pure and mixed electrolyte solutions and criteria of phase equilibria,
predicted solubility behavior of salts was compared with experimental results from literature. The agreement between calculated
and experimental solubilities was excellent in the ionic strength range up to 10.9062 mol kg−1. 相似文献
19.
Weijuan Huang Yixiang Wang Lina Zhang Lingyun Chen 《Cellulose (London, England)》2016,23(6):3463-3473
Dissolution of cellulose is the key challenge in its applications. It has been discovered that spruce cellulose with high molecular weight (4.10 × 105 g mol?1) can be dissolved in 64 wt% H2SO4 aqueous solution at low temperature within 2 min, and the cellulose concentration in solution can reach as high as 5 % (w/v). FT-IR spectra and XRD spectra proved that it is a direct solvent for cellulose rather than a derivative aqueous solution system. The cold H2SO4 aqueous solution broke the hydrogen bonds among cellulose molecules and the low temperature dramatically slowed down the hydrolysis, which led to the dissolution of cellulose. The resultant cellulose solution was relatively stable, and the molecular weight of cellulose only slightly decreased after storage at ?20 °C for 1 h. Due to the high molecular weight of cellulose, cellulose solution could form regenerated films with good mechanical properties and transparency at low concentration (2 % w/v). This work has not only provided the new evidence of cellulose dissolution which facilitated the development of cellulose solvent, but also suggested a convenient way to directly transfer cellulose with high molecular weight into materials without structure modifications. 相似文献