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排序方式: 共有239条查询结果,搜索用时 31 毫秒
41.
Journal of Nanoparticle Research - In this work, atypical zinc oxide nanorods (ZnO NRs) on quartz substrates were successfully synthesized using simple, low-cost, and environmentally friendly... 相似文献
42.
Cu(ClO4)2·6H2O has been found to be an efficient catalyst for cyanosilylation reaction of aldehydes in THF at room temperature with low catalytic loading (1.0 mol%) in short reaction time (mostly within 10 min). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
43.
Alkylation of p-cresol with tert-butanol catalyzed by heteropoly acid supported on zirconia catalyst
Biju M. Devassy G. V. Shanbhag F. Lefebvre S. B. Halligudi 《Journal of molecular catalysis. A, Chemical》2004,210(1-2):125-130
Butylation of p-cresol by tert-butanol was catalyzed by 12-tungstophosphoric acid supported on zirconia (TPA/ZrO2) under flow conditions. Catalysts prepared with different TPA loading (5–30 wt.%) were calcined at 1023 K and acidity was estimated by temperature programmed desorption (TPD) of NH3. Fifteen percent TPA/ZrO2 showed the highest acidity and found to be the most active catalyst in butylation of p-cresol. The effects of temperature, space velocity (LHSV) and molar ratio of the reactants on the conversion of p-cresol and products selectivities were optimized and the optimum reaction conditions evaluated were 403 K, tert-butanol/p-cresol (Bu/Cr) molar ratio 3 and LHSV 4 h−1. Under the optimized conditions, conversion of p-cresol was found to be 61 mol% with product selectivity for 2-tert-butyl-p-cresol (TBC) 81.4%, 2,6-di-tert-butyl-p-cresol (DTBC) 18.1% and tert-butyl-p-tolyl ether (ether) 0.5%. Study of time on stream (TOS) performed as a function of time for 100 h showed that the loss in activity in terms of conversion of p-cresol was 6%. 相似文献
44.
Biju V Makita Y Sonoda A Yokoyama H Baba Y Ishikawa M 《The journal of physical chemistry. B》2005,109(29):13899-13905
The formation of narrow size dispersed and nanometer size aggregates (clusters) of cadmium selenide (CdSe) quantum dots (QDs) and their temperature-sensitive photoluminescence (PL) spectral properties close to room temperature (298 K) are discussed. CdSe QDs formed stable clusters with an average diameter of approximately 27 nm in the absence of coordinating solvents. Using transmission electron microscopy (TEM) imaging, we identified the association of individual QDs with 2-5 nm diameters into clusters of uniform size. A suspension of these clusters in different solvents exhibited reversible PL intensity changes and PL spectral shifts which were correlated with temperature. Although the PL intensity of CdSe QDs encapsulated in host matrixes and the solid state showed a response to temperature under cryogenic conditions, the current work identified for the first time QD clusters showing temperature-sensitive PL intensity variations and spectral shifts at moderate temperatures above room temperature. Temperature-sensitive reversible PL changes of clusters are discussed with respect to reversible thermal trapping of electrons at inter-QD interfaces and dipole-dipole interactions in clusters. Reversible luminescence intensity variations and spectral shifts of QD clusters show the potential for developing sensors based on QD nanoscale assemblies. 相似文献
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Avishek Ghosh Tulasi Barik Smriti Dewangan Paresh Kumar Majhi Takahiro Sasamori Shaikh M. Mobin Santanab Giri Saurav Chatterjee 《应用有机金属化学》2019,33(4)
A novel solvent free synthetic method has been designed by using rice husk ash (RHA) as solid support for the selective functionalization of ferrocenyl derivatives and described the synthesis of a 1,1′‐unsymmetrically bi‐functionalized ferrocenyl compounds for their biological evaluation. Single crystal X‐ray structural evaluation showed some interesting intra‐molecular hydrogen bonding interactions across the chains of the ferrocenyl molecule, while DFT calculation revealed the significance of the orientation between the two cyclopentadienyl rings for the hydrogen bonding interaction. Redox and antibacterial properties have been studied to understand the electronic and biological effect of different hydrazone system and their potential for future application. 相似文献
48.
Biju Joseph K. A. Venkatesan K. Nagarajan T. G. Srinivasan P. R. Vasudeva Rao 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(1):167-171
Lithium assisted electrochemical reduction of U3O8 in the room temperature ionic liquid (RTIL), N-methyl-N-propylpiperidinium bis(trifluoromethylsulfonyl)imide (MPPiNTf2), was studied to explore the feasibility of using RTILs for direct electrochemical reduction of uranium oxide at near ambient
temperature. The electrochemical behavior of Li+ in MPPiNTf2 at stainless steel electrode was investigated by cyclic voltammetry and chronoamperometry. The cyclic voltammogram of LiNTf2 in MPPiNTf2 at 373 K consisted of a surge in cathodic current occurring at a potential of −2.8 V (vs. Fc/Fc+) due to the reduction of Li(I) to metallic form. The nucleation phenomenon observed in the voltammogram was investigated
by chronoamperometry. Electrodeposition of metallic lithium on U3O8 particles contained in a stainless steel (SS) basket was carried out to examine the feasibility of reducing U3O8 to metallic form. The results are discussed in this paper. 相似文献
49.
1 The single stranded-helicate Vanadium(IV) complex [V2O2Cl4(L)(H2O)2] (1) involving heterocyclic bis-bidentate ligand viz. 3,3/-dipyridine-2-yl-[1.1/]bi[imidazo[1,5-a]pyridineyl] (L) with biological relevance is prepared and characterized by X-ray diffraction analysis. The compound lacks molecular center of symmetry where coordination environments around V(1) and V(2) centres are distorted octahedral (V···V# separation of 5.827 Å). Structure of the compound in the solid state structure shows anion?π interactions, classical and Carene-H---anion non-classical H-bonding interactions. These interactions play significant roles in shaping the extended structure of this molecule. 相似文献
50.
Inside Cover: tert‐Butyl Nitrite Mediated Regiospecific Nitration of (E)‐Azoarenes through Palladium‐Catalyzed Directed CH Activation (Chem. Eur. J. 32/2014)
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