共查询到20条相似文献,搜索用时 31 毫秒
1.
O. A. Fedyaeva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2012,86(3):447-451
The adsorption of ammonia, oxygen, and the NH3 + O2 mixture on solid solutions Cd
x
Hg1 − x
Te is studied. The low adsorbability of the mixture, as compared to that of the individual components, is established. Conclusions
are drawn as to the nature of its active centers. Schemes for the combined adsorption of ammonia and oxygen are proposed.
The temperature areas of tentatively highest catalytic activity of CdTe and CdHgTe in the reaction of ammonia oxidation are
established. The formation of gaseous nitrogen in the final products is demonstrated. The degree of ammonia’s transformation
into nitrogen is 97–99%. It increased with a rise in temperature and did not depend on the initial ammonia concentration. 相似文献
2.
O. A. Fedyaeva 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2011,85(12):2233-2236
The acid-base properties of actual CdTe and CdHgTe surfaces were investigated by means of non-aqueous conductometric titration
for pHpzc determination, mechanochemistry, and UV spectroscopy. It was shown that the alkaline nature of their surface was
due to the dissociative adsorption of atmospheric water flowing on the coordination-saturated surface atoms of cadmium with
vacancy defects. The adsorbed water was involved in the formation of tellurium oxide TeO2 and H2TeO3 tellurous acid in the dispersion of CdTe and CdHgTe. 相似文献
3.
Formation of active phases of Fe/C,Cr/C and Fe–Cr/C catalysts in oxidative dehydrogenation of ethane
《Mendeleev Communications》2023,33(3):422-424
The oxidative dehydrogenation of ethane into ethylene using CO2 as an oxidant at temperatures of 650–750 °C was carried out over Fe/C, Cr/C and Fe–Cr/C catalysts deposited on a carbon support. Before and after the reaction the catalysts were investigated by X-ray powder diffraction (XRD), in situ magnetometry and transmission electron microscopy methods. The correlation between activity of Fe/C, Cr/C and Fe–Cr/C catalytic systems and their phase composition was established. 相似文献
4.
Multi-substituted quinolines 3 were unexpectedly prepared from a cascade reaction of ortho-azido-β-nitro-styrenes with various carbonyl compounds. This method takes advantages of mild condition, simple work-up, high yield as well as wide substrate scope, which makes this method powerful for one-pot synthesis of multi-substituted quinolines. 相似文献
5.
The quantum-chemical calculations of the (C6H5)2PCl3 molecule were performed by the methods RHF/6-31G(d) and MP2/6-31G(d) with complete and partial optimization of its geometry.
The results of calculations were used for evaluating the NQR frequencies of 35Cl and the parameters of asymmetry of the of electric field gradient on the 35Cl nuclei of this molecule. According to the results of calculations with the partial optimization of geometry and to the
experimental data of 35Cl NQR the bond lengths were found of central atom P in the solid state of this compound. The mutual influence of its axial
and equatorial bonds was studied. It is shown that in chlorophosphoranes the 35Cl NQR frequencies of the axial and equatorial chlorine atoms decrease with the decrease in the bond lengths of phosphorus
atom. 相似文献
6.
A. S. Monaenkova A. A. Popova L. A. Tiflova E. A. Gudilin 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(8):1280-1284
The enthalpies of reactions of substitution solid solutions Pr1 + x
Ba2 − xCu3O
y
, where x = 0, 0.2, 0.4, 0.6, and 0.9, with 1.07 N HCl were measured at 298.15 K in a hermetic swinging isothermic-shell calorimeter.
The results and the literature data were used to calculate the standard enthalpies of formation of solid solutions from the
elements and oxides. The dependence of the enthalpy of solid solution formation on the degree of praseodymium substitution
for barium (x) was revealed. 相似文献
7.
Salari M. A. Sağlam M. Baltakesmez A. Güzeldir B. 《Journal of Radioanalytical and Nuclear Chemistry》2019,319(3):667-678
In this study, RF-magnetron sputtered ZnO thin film as an interlayer was used to improve radiation tolerance of the Schottky diodes. The structural and optical measurements showed that the ZnO thin films have hexagonal crystal structure with preferential c-axis orientation, 20.39 nm grain sizes and 3.15 eV bandgap. The electrical parameters such as ideality factor, barrier height and series resistance of Zn/n-Si/Au–Sb and Zn/ZnO/n-Si/Au–Sb diodes were calculated before and after electron radiation at 25, 50 and 75 gray doses. Deviation values of the parameters showed that the ZnO as an interlayer caused to improved radiation tolerance of the diodes.
相似文献8.
A. S. Monaenkova A. A. Popova L. A. Tiflova M. L. Kovba 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2010,84(7):1085-1088
The enthalpies of reactions of Sm1 + x
Ba2 − x
Cu3O
y
substitution solid solutions (x = 0, 0.1, 0.2, 0.3, 0.7, and 0.8) with 1.07 N HCl were measured at 298.15 K in a hermetic isothermic-shell swinging calorimeter.
The results and the literature data were used to calculate the standard enthalpies of their formation from simple substances
and binary oxides (Δf
H
298.15o and Δox
H
298.15o). The dependence of the enthalpy of formation on the degree of samarium substitution for barium was obtained. 相似文献
9.
E. A. Filonova A. N. Petrov 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2009,83(11):1832-1835
The homogeneity regions of Nd1 − x
Ba
x
MnO3 (0.0 ≤ x ≤ 0.25) and NdMn1 − y
Fe
y
O3 (0.0 ≤ y ≤ 1.0) orthorhombic solid solutions in air at 1373 K were determined. The region of the existence of Nd1 − x
Ba
x
Mn1 − y
Fe
y
O3 orthorhombic solid solutions in air at 1373 K was studied. A fragment of the phase diagram of the NdMnO3-BaMnO3-BaFeO2.5-NdFeO3 quasi-quaternary complex oxide system in air at 1373 K was suggested. The mechanothermal properties of Nd0.75Ba0.25MnO3, Nd0.8Ba0.2Mn0.9Fe0.1O3, Nd0.8Ba0.2Mn0.7Fe0.3O3, and Nd0.8Ba0.2Mn0.5Fe0.5O3 doped neodymium manganates were studied. 相似文献
10.
Observation that rates of dehydrobromination of trans-β-bromostyrene (1) and the Hofmann degradation of tetrabutyl ammonium cation depend on strength of base in different ways and that treatment of 1 with base results in fast abstraction of the β-proton imply the possibility that the dehydrobromination of 1 could proceed via α-elimination and Ph migration. In order to clarify this question, β-13C-labeled 1 was obtained and subjected to PTC dehydrobromination which proceeds without migration of Ph. The obtained results are consistent with an irreversible E1cB mechanism. 相似文献
11.
Mi?osz Mi?tkiewski Beata Powa?a Bartosz Staniszewski Maciej Kubicki W?odzimierz Urbaniak Cezary Pietraszuk 《Central European Journal of Chemistry》2011,9(4):728-736
Selected β-diketones bearing unsaturated derivatives have been demonstrated to undergo homo-metathesis and cross-metathesis with selected
olefins in the presence of Grubbs catalysts. The reactions led to respective homo- and cross-metathesis products mainly with
good yields and selectivities.
相似文献
12.
Pilar Pérez-Puente Juan C. Flores Pilar Gómez-Sal 《Journal of organometallic chemistry》2008,693(26):3902-3906
2-(N-aryliminomethyl)pyrrole precursors (2,6-R2-C6H3-NCH-2-C4H3NH) (R = Me, IH; R = iPr, IIH) were prepared and transformed into their corresponding sodium salts (Na+I− and Na+II−) by treatment with NaH. Both salts readily react with [NiBr2(DME)] (DME = 1,2-dimethoxyethane) to give the respective bis{2-(N-arylimino-κN-methyl)pyrrolide-κN}nickel(II) complexes (1, 2) in almost quantitative yields. The oxidative addition of IH to [Ni(COD)2] (COD = 1,5-cyclooctadiene) results in the formation of 3, which is a mono(iminomethylpyrrolide)-η3-(cyclic-allyl)-type organonickel(II) complex. The crystal structure of compound 1 has been established by X-ray diffraction studies. 相似文献
13.
The potentiostatic intermittent titration technique is used to study lithium transport in the LiM
yMn2 − y
O4 compounds with a spinel structure intended for application as cathodic materials in lithiumion and lithium-polymer batteries.
The materials are synthesized using the sol-gel method and the melt-impregnation method. Kinetic and diffusion characteristics
of the Li
x
Mn2O4 and Li
x
Mn1.95Cr0.05O4 compounds are determined at 25°C as dependent on lithium content 0 < x < 1. The diffusion coefficient of lithium varies significantly in the range of 10−10 to 10−13 cm2/s under variation of the electrode composition; the surface resistance depends weakly on the concentration of lithium and
is 200–500 Ohm cm2. 相似文献
14.
A. V. Mashkina S. N. Koshelev V. N. Yakovleva V. R. Grunvald B. P. Borodin V. I. Nasteka 《Reaction Kinetics and Catalysis Letters》1991,43(2):381-386
In the presence of -Al2O3 at 200–500°C methylmercaptans quantitatively transform into dimethyl sulfides with almost equilibrium degrees of conversion. 100% selectivity towards diethyl sulfide is observed when ethylmercaptan conversion amounts to about 50% of its equilibrium value. In more severe conditions, dimethyl- and diethyl sulfides convert with eliminating hydrocarbons and H2S. Selectivity towards diisopropylsulfide is as high as 30% with isopropylmercaptane conversion up to 25%; the reaction follows a parallel-consecutive scheme.
-Al2O3 200–500°C . 100% 50% . - H2S. 30% 25%, - .相似文献
15.
16.
Chao Jun JING Liu Sheng CHEN Yi SHI Xi Gao JIN 《中国化学快报》2005,16(8):1117-1120
The synthesis of poly(2-methoxy-5-(2'-ethyl-hexyloxy)-l,4-phenylenevinylene) (MEH-PPV) in the presence of organophilic montmorillonite (OMMT) was reported and the exfoliated MEH-PPV/OMMT nanocomposites was obtained by controlling the ratio of the monomer to the OMMT. 相似文献
17.
The mechanism and kinetics of the production of hydroxymethyl hydroperoxide (HMHP) in ethene/ ozone/water gas-phase system were investigated at room temperature (298±2 K) and atmospheric pressure (1×105 Pa). The reactants were monitored in situ by long path FTIR spectroscopy. Peroxides were measured by an HPLC post-column fluorescence technique after sampling with a cold trap. The rate constants (k3) of reaction CH2O2 H2O→HMHP (R3) determined by fitting model calculations to ex-perimental data range from (1.6―6.0)×10?17 cm3·molecule?1·s?1. Moreover, a theoretical study of reac-tion (R3) was performed using density functional theory at QCISD(T)/6-311 (2d,2p)//B3LYP/6-311 G(2d, 2p) level of theory. Based on the calculation of the reaction potential energy surface and intrinsic reac-tion coordinates, the classic transitional state theory (TST) derived k3 (kTST), canonical variational tran-sition state theory (CVT) derived k3 (kCVT), and the corrected kCVT with small-curvature tunneling (kCVT/SCT) were calculated using Polyrate Version 8.02 program to be 2.47×10-17, 2.47×10-17 and 5.22×10-17 cm3·molecule-1·s-1, respectively, generally in agreement with those fitted by the model. 相似文献
18.
Wei DENG Ye Feng WANG Chen ZHANG Lei LIU Qing Xiang GUO 《中国化学快报》2006,17(3):313-316
Qing Xiang GUON-Arylated heterocycles such as pyrroles, indoles, and imidazoles are important building blocks for the synthesis of natural products, pharmaceuticals, and function materials1. Usually these compounds were synthesized by Cu-catalyzed Ullmann… 相似文献
19.
The galvanostatic intermittent titration technique is used to study lithium transport in the LiM
y
Mn2 − y
O4 compounds with a spinel structure intended for application as cathodic materials in lithium-ion and lithium-polymer batteries.
Equilibrium intercalation isotherms of the Li
x
Mn2O4 and Li
x
Mn1.95Cr0.05O4 compounds and also their diffusion characteristics are determined at 25°C as dependent on lithium content x, 0 < x < 1. The diffusion coefficient of lithium varies in a complex way in the range of 10−10 to 10−12 cm2/s under variation of the electrode composition. 相似文献
20.
P. A. Romodanovskii N. G. Dmitrieva S. N. Gridchin P. N. Vorob’ev 《Russian Journal of Inorganic Chemistry》2011,56(9):1491-1493
The enthalpies of solution of sodium metavanadate dihydrate in aqueous solutions of sodium perchlorate at ionic strength I = 0.3, 0.5, and 1.0 mol/L were calorimetrically measured at 298.15 K. The resulting experimental data were used to calculate
the standard enthalpy of formation of crystalline NaVO3 · 2H2O. 相似文献