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71.
Lingaiah Nagarapu Gopal Paturi Satyender Apuri Rajashaker Bantu Renuka Bhavanthula 《合成通讯》2013,43(2):355-365
A simple and efficient procedure has been developed for one-pot synthesis of homoallylic alcohols and amines in good to excellent yields using a variety of aldehydes, amines, and allyltributylstannane in the presence of a catalytic amount of potassium dodecatungsto cobaltate trihydrate (K5CoW12O40 · 3H2O) as a heterogeneous catalyst at room temperature. The catalyst exhibited remarkable reusability. 相似文献
72.
S. Sugunan N. K. Renuka A. R. Koshy S. M. Varghese C. G. Ramankutty 《Reaction Kinetics and Catalysis Letters》1999,67(2):267-271
The surface acidity and basicity of vanadium pentoxide supported on CeO2 were determined using a set of Hammett indicators. The data have been correlated with the catalytic activity of these oxides
towards liquid phase acylation of phenol. 相似文献
73.
B. Vijaya Kumar V. Rama Devi G. Prasad M. Kanagaraj M. Vithal 《Journal of solid state chemistry》2011,184(2):264-272
Bulk and nanosized pyrochlore materials Ln2ZrTiO7 (Ln=La, Eu, Dy, Gd and Sm) have been prepared by the sol-gel method. All the samples were characterized by powder X-ray diffraction, Raman and X-ray photoelectron spectroscopy. Magnetic susceptibility (χ) measurements of Gd2ZrTiO7, Sm2ZrTiO7 and Eu2ZrTiO7 were carried out by vibrating sample magnetometer in the temperature range 2-320 K. The variation of χ−1 (or χ) with temperature of Gd2ZrTiO7, Sm2ZrTiO7 and Eu2ZrTiO7 follows the Curie law, intermediate formula and the Curie-Weiss law, respectively. From the linear portion of χT vs. T−1 plot of Eu2ZrTiO7 from 2 to 15 K, the classical nearest neighbor exchange (Jcl) and dipolar interactions (Dnn) are obtained. The XPS of Ln2ZrTiO7 (Ln=La, Eu, Dy and Gd) gave characteristic peaks for Ln, Ti, Zr and O. The satellite peaks are observed only for 3d La of La2ZrTiO7. 相似文献
74.
75.
M. J. Kurian S. Jyothi S. K. Leju Molly Isaac Chandu Venugopal G. Renuka 《Pramana》2009,73(6):1111-1122
We have studied the stability of the electrostatic ion cyclotron wave in a plasma consisting of isotropic hydrogen ions (H+) and temperature-anisotropic positively (O+) and negatively (O−) charged oxygen ions, with the electrons drifting parallel to the magnetic field. Analytical expressions have been derived
for the frequency and growth/damping rate of ion cyclotron waves around the first harmonic of both hydrogen and oxygen ion
gyrofrequencies. We find that the frequencies and growth/damping rates are dependent on the densities and temperatures of
all species of ions. A detailed numerical study, for parameters relevant to comet Halley, shows that the growth rate is dependent
on the magnitude of the frequency. The ion cyclotron waves are driven by the electron drift parallel to the magnetic field;
the temperature anisotropy of the oxygen ions only slightly enhance the growth rates for small values of temperature anisotropies.
A simple explanation, in terms of wave exponentiation times, is offered for the absence of electrostatic ion cyclotron waves
in the multi-ion plasma of comet Halley. 相似文献
76.
The blend-based polymer electrolyte consisting of poly (vinyl chloride) (PVC) and poly (ethylene glycol) (PEG) as host polymers
and lithium perchlorate (LiClO4) as the complexing salt was studied. An attempt was made to investigate the effect of TiO2 concentration in the unplasticized PVC–PEG polymer electrolyte system. The XRD and FTIR studies confirm the formation of
a polymer–salt complex. The conductivity results indicate that the incorporation of ceramic filler up to a certain concentration
(15 wt.%) increases the ionic conductivity and upon further addition the conductivity decreases. The maximum ionic conductivity
0.012 × 10−4 S cm−1 is obtained for PVC–PEG–LiClO4–TiO2 (75–25–5–15) system. Thermal stability of the polymer electrolyte is ascertained from TG/DTA studies. 相似文献
77.
78.
将V2O5, CeO2和CuO分散到提取自稻米壳的SBA-16上,考察了其催化CO氧化反应活性,并采用X射线衍射、扫描电镜、透射电镜、程序升温还原和紫外漫反射光谱对所制催化剂进行了表征。结果表明,掺杂CuO的介孔氧化硅是一种有前景的催化剂,其CO转化率可达98%以上。 相似文献
79.
Radha Velchuri Ramaswamy Kadari Gundeboina Ravi Nagegownivari R. Munirathnam Muga Vithal 《无机化学与普通化学杂志》2015,641(5):935-940
Silver/copper‐nitrogen co‐doped Na3SbO(PO4)2 were prepared by solid state/ion exchange methods. The materials were characterized by powder XRD, SEM‐EDS, TG analysis, as well as FT‐IR and UV/Vis diffuse reflectance spectroscopy. All the doped materials crystallize in orthorhombic lattice with space group P212121. The infrared spectra of the samples gave characteristic bands corresponding to PO4 and SbO6 groups. The bandgap energy of all the samples was deduced from their UV/Vis DRS profiles. The bandgap energy of doped materials decreased substantially. Visible‐light‐induced photocatalytic oxidation of the methyl violet (MV) and methylene blue (MB) was examined. The influence of cation, anion, and co‐doping on the photoactivity of Na3SbO(PO4)2 was studied. The Ag+ and nitrogen co‐doped Na3SbO(PO4)2 exhibited the highest photocatalytic activity among the materials investigated. 相似文献
80.
A polymer-supported cobalt complex of 2,6-bis(benzimidazolyl)pyridine (BBP) was synthesized by immobilization of BBP on chloromethylated polystyrene cross-linked with 6.5 % divinylbenzene, followed by complexation with CoCl2 in methanol, and characterized by physico-chemical and spectroscopic methods. The polymer-bound Co(PS–BBP)Cl2 was found to be more stable compared to free Co(BBP)Cl2 as determined by TGA analyses. The catalytic activity of Co(PS–BBP)Cl2 was investigated towards oxidation of benzene, ethylbenzene and cyclohexane using tert-butylhydroperoxide as oxidant. At optimum conditions, benzene showed 72.6 % conversion with 100 % selectivity towards phenol; ethylbenzene exhibited 97.0 % conversion with 82.5 and 17.4 % selectivity towards benzaldehyde and acetophenone, respectively, whilst conversion of cyclohexane was 60.0 with 75.8 and 24.1 % selectivity towards cyclohexanol and cyclohexanone. The unsupported complex Co(BBP)Cl2 showed lower activities and selectivities compared to the polymer-supported complex. Co(PS–BBP)Cl2 was found to be very active and reusable, giving high yields of the desired products. A possible reaction mechanism is proposed for these oxidation reactions. 相似文献