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471.
Sustainable existence of solid mercury (Hg) nanoparticles at room temperature and their applications
Villa Krishna Harika Tirupathi Rao Penki Boddapati Loukya Atanu Samanta Gui-Liang Xu Cheng-Jun Sun Ilya Grinberg Francis Leonard Deepak Khalil Amine Doron Aurbach Aharon Gedanken 《Chemical science》2021,12(9):3226
Although liquid mercury (Hg) has been known since antiquity, the formation of stable solid nano forms of Hg at room temperature has not been reported so far. Here, for the first time, we report a simple sonochemical route to obtain solid mercury nanoparticles, stabilized by reduced graphene oxide at ambient conditions. The as-formed solid Hg nanoparticles were found to exhibit remarkable rhombohedral morphology and crystallinity at room temperature. Extensive characterization using various physicochemical techniques revealed the unique properties of the solid nanoparticles of Hg compared to its bulk liquid metal phase. Furthermore, the solid nature of the Hg nanoparticles was studied electrochemically, revealing distinctive properties. We believe that solid Hg nanoparticles have the potential for important applications in the fields of electroanalytical chemistry and electrocatalysis.Formation of the stable solid mercury nanoparticles by acoustic cavitation and their electrochemical activity compared to its bulk liquid metal. 相似文献
472.
Tushar Kanti Chakraborty Rajarshi Samanta Krishnan Ravikumar 《Tetrahedron letters》2007,48(36):6389-6392
Radical-mediated opening of chiral 2,3-epoxy alcohols, containing suitably positioned β-(alkoxy)acrylate moieties, using Cp2TiCl triggered intramolecular cyclization to give tetrahydrofuran and tetrahydropyran moieties. 相似文献
473.
Ghosh D Mukhopadhyay S Samanta S Choi KY Endo A Chaudhury M 《Inorganic chemistry》2003,42(22):7189-7199
Nickel(II) complexes of three new heterodonor ligands (HL(1), H(2)L(2), and H(3)L(3)) based on 2-aminocyclopent-1-ene-1-dithiocarboxylate have been synthesized, and their crystallographic characterizations are reported. With the pentacoordinating ligands HL(1) and H(3)L(3), the products obtained (1 and 2) are both mononuclear square planar compounds in which one of the pyrazolyl arms of ligand HL(1) and the bridgehead alkoxy oxygen of H(3)L(3) are staying away from coordination in 1 and 2, respectively. The saturated three carbon alkanyl chain in the ligand H(3)L(3) provides enough flexibility to generate tetrahedral distortion (dihedral angle, 22.7 degrees ) in the planarity of 2. Compound 1 displays paramagnetic line-broadening in its (1)H NMR spectrum due to oligomerization in solution. With the unsymmetrical binucleating ligand H(2)L(2), two mixed-spin homodinuclear complexes (3 and 4) have been synthesized using pyrazole and 2-mercaptopyridine as ancillary mu(2)-bridging ligands. Both these complexes have square planar low-spin and spin-triplet nickel(II) centers which display both coordination number and donor set asymmetry in tandem. The compounds have been characterized by (1)H NMR, electronic spectroscopy, and electrochemical studies. 相似文献
474.
Krishna C. Majumdar Uday K. Kundu Swapan K. Samanta Nirmal K. Jana 《Monatshefte für Chemie / Chemical Monthly》2003,25(6):1137-1143
Two hitherto unreported pyrimidine annelated heterocycles were synthesized from 6-cyclopent-2-enyl-5-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione and 5-cyclopent-2-enyl-6-hydroxy-1,3-dimethylpyrimidine-2,4(1H,3H)-dione by reaction with pyridine hydrotribromide or hexamethylenetetramine hydrotribromide. The first one was also obtained by reaction with concentrated sulfuric acid. 相似文献
475.
476.
477.
V.R. Choudhary C. Samanta T.V. Choudhary 《Journal of molecular catalysis. A, Chemical》2006,260(1-2):115-120
Since H2O2 decomposition can result in selectivity/yield loss in the direct H2O2 synthesis process from H2 and O2 over supported Pd catalysts, it is important to have an enhanced understanding about the factors affecting the H2O2 decomposition reaction. Herein, detailed studies have been undertaken to investigate the influence of different factors, such as (a) nature and concentration of acid in reaction medium, (b) nature and concentration of halide in presence and absence of acid in reaction medium, (c) pretreatment procedures and (d) catalyst modification by incorporation of different halides, on the H2O2 decomposition reaction over a 5% Pd/C catalyst in aqueous medium at 25 °C. This study has shown that the H2O2 decomposition activity is profoundly influenced by all the above factors. The effectiveness of the acids in suppressing the H2O2 decomposition activity decreased in the following order: hydroiodic acid > hydrobromic acid > hydrochloric acid acetic acid > phosphoric acid > sulfuric acid > perchloric acid. The ability of the acid to decrease the H2O2 decomposition activity was found to very strongly depend on the nature of its associated anion. Halides, such as iodide, bromide and chloride were particularly effective in suppressing the H2O2 decomposition activity. Oxidation pretreatment of the catalyst was found to strongly suppress its H2O2 decomposition activity, while a reduction treatment was found to promote its activity. A gradual decrease in the H2O2 decomposition activity of the catalyst was observed with each successive usage due to in situ sub-surface oxidation of Pd by H2O2. Halide incorporation either via the reaction medium or prior catalyst modification had a similar qualitative effect on the H2O2 decomposition activity. 相似文献
478.
S. K. Samanta 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(2):585-588
A locally produced mordenite type synthetic zeolite and its modified form obtained by the treatment with dilute hydrochloric
acid were tested for their cesium uptake characteristics. The two zeolites were compared with other commercially available
synthetic zeolites with respect to their ability to sorb radiocesium from dilute nitric acid solution. The effects of the
changes in the composition of the solution including the concentration of nitric acid, sodium and cesium on the uptake of
cesium were investigated. The results can be used in the removing processor radiocesium from different types of nuclear plant
effluents by these zeolites. 相似文献
479.
480.
This paper analyzes a finite-buffer multiserver bulk-service queueing system in which the interarrival and service times are, respectively, arbitrarily and exponentially distributed. Using the supplementary variable and the imbedded Markov chain techniques, we obtain the queue-length distributions at prearrival and arbitrary epochs. We also present Laplace–Stiltjes transform of the actual waiting-time distribution in the queue. Finally, several performance measures and a variety of numerical results in the form of tables and graphs are discussed. 相似文献