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141.
We report a new and efficient ruthenium-catalyzed reaction that transforms ethynyl alcohol into alkene and carbon monoxide. The most efficient catalysts are TpRu(PPh3)(CH3CN)2PF6 (10 mol %) and lithium triflate (20 mol %). The mechanism of this reaction was elucidated using an isotope-labeling experiment. 相似文献
142.
After the era of industrialization, technology is developing daily since the last century. Urbanization, communication, and transportation have grown rapidly and simultaneously deforestation and volcanic eruptions take place on a large scale. As result every moment tons of foreign particles like soot, dust, ash, and bio-fuel contaminants are released into the atmosphere. These contaminants mix with air and various green house gases, form a blanket structure in atmosphere. This mixture of ultrafine particle suspension with atmospheric air is known as aerosol. In the present study, numerical simulations of hydrodynamic single cell buoyant convection of atmospheric aerosol sample enclosed within a gray enclosure in the presence of a transverse magnetic field and surface radiation is addressed. Flow of the aerosol over deserts and industrial belts is a practical example of such a condition, where the thermal radiation emanating from the surface, affects the flow mechanism of the aerosol transport. The emphasis of the present study is only on carbon-black solid particles of a size in the nanometer range present in atmospheric air. The aerosol is treated as nanofluid for the numerical simulation. A comprehensive study on the controlling parameters that affect the flow and heat transfer characteristics are delineated. The governing equations are solved using modified MAC method and SIMPLER algorithm has been used to solve pressure velocity coupling employing relaxation technique. The transport equation for surface radiation is solved using the net radiation method. The cross string method is used to evaluate the view factor. The most striking result is that the heat transfer rate increases with increase in the volume fraction of the carbon-black particles, which has an adverse effect on both the climate and living creatures. The results are presented in tabular and graphical form. The heat transfer and flow characteristics are depicted in the form of isotherms and streamlines revealing the physics of this complex phenomenon. 相似文献
143.
Swarup De Elisabetta Groaz Mohitosh Maiti Valérie Pezo Philippe Marlière Piet Herdewijn 《Tetrahedron》2014
In search for a delivery approach for thymidine monophosphate (TMP) in bacterial cells, we have synthesized a series of conjugates of TMP with biotin having an oxymethyleneoxy ester, a carboxy ester, and different carboxamide linkers between the carboxyl group of biotin and the 3′-OH group of TMP. The synthetic strategy starts from 5′-O-(dibenzylphosphate)-thymidine having the linkers already connected at the 3′-position. Likewise, kanamycin A was linked at the 3′-position of TMP using a carbamoyl or thioethyl carbamoyl group. None of the conjugates were able to sustain growth of a ΔthyA, ΔphoA Escherichia coli strain. 相似文献
144.
1-D morphological tuning in the riboflavine(R)-melamine(M) hydrogel system (from helical fiber to rod-like to tubular morphology) with an interesting photoluminescence property by changing the composition of the RM components. 相似文献
145.
Narottam Gharah Basab Chattopadhyay Swarup K. Maiti Monika Mukherjee 《Transition Metal Chemistry》2010,35(5):531-539
(PPh4)2[MoO(O2)2(SHAH)]·H2O and PPh4[MoO(O2)2(HBA)] (SHAH3 = 2-hydroxybenzohydroxamic acid and HBAH = 2-hydroxybenzoic acid) have been synthesized and characterized by physico-chemical
and spectroscopic methods. In addition, the second complex has been structurally characterized by single-crystal X-ray diffraction
analysis. We have compared the catalytic activities of these two new complexes, together with the previously reported PPh4[MoO(O2)2(BZ)] (BZH = benzoic acid), with respect to the epoxidation of alkenes. The hydroxamate complex is the most efficient catalyst
among the three complexes, showing excellent catalytic activity for the substrates cyclohexene, cyclooctene, cinnamyl alcohol,
pent-4-en-1-ol and hex-1-ene. 相似文献