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991.
Yang LI Yu ZHANG Xiao Long WANG Zhi HUANG Xiao Ping CAOState Key Laboratory of Applied Organic Chemistry College of Chemistry Chemical Engineering Lanzhou University Lanzhou 《中国化学快报》2004,(6)
A convenient and rapid approach for the synthesis of piperamide alkaloids la ~ h by the recently developed one-flask Ramberg-Backlund reaction was described. The synthesis of 1e was reported for the first time. 相似文献
992.
993.
单分散纳米InVO4(正交相)的低温合成 总被引:1,自引:0,他引:1
InVO4 is a new developed visible light responding photocatalyst for water decomposition, which is obtained by a solid-state reaction at high temperature traditionally. In this paper, pure InVO4 nano-crystalline powder has been prepared by a hydrothermal process at low temperature and was characterized by TEM, IR, and X-ray diffraction. Many factors such as pH value, reaction time and temperature have been investigated. It is found that the optimal conditions for the preparation is: nInCl3∶nNaVO3=1∶2; temperature : 150 ℃; Reaction time: 4~8 h; pH=7.9~8.0. And the experimental result shows that it is a convenient way to get single dispersing InVO4 nano-crystalline powder by flux in alkyl alcohol. 相似文献
994.
噻吩加氢脱硫和四氢萘催化加氢反应中的载体和助剂的影响 总被引:9,自引:0,他引:9
为了更好地认识加氢脱硫和催化加氢反应中的载体影响和助剂效应,在同样的催化剂制备方法及反应条件下,研究了噻吩加氢脱硫(HDS)和四氢萘催化加氢(HYD)反应.结果表明,对于无助剂的Mo和W催化剂,载体对催化活性的影响顺序为TiO2-Al2O3>ZrO2>Al2O3.助剂的添加改变了催化剂活性顺序.Ni助剂催化剂的活性明显高于Co助剂催化剂.ZrO2担载的添加Ni的Mo和W催化剂分别获得了最佳的HDS和HYD活性.然而,添加Pt的Mo和W催化剂其HDS和HYD活性仅是Pt与Mo(W)二者的加和,Pt与Mo(W)之间没有协同效应.先将担载的Mo和W预硫化再将助剂引入体系的催化剂制备方法可以避免Ni和Co过早硫化形成类硫化镍(或硫化钴)物相,与采用螯合物分子方法制备的催化剂间有一定的相似性. 相似文献
995.
1INTRODUCTIONInthepastfewyears,potassiumchannelacti-vatorshavegainedincreasingattentionbecauseoftheirclinicalpotentialapplicationsinvariousdiseases.Oneofthemostpotentcompoundsamongthisnewclassofdrugsisthebenzopyranderivativecroma-kalim[1~4].Benzopyranaswellasitsderivativesex-hibitsextensivepharmacologicalandbiologicalacti-vities[5],suchasantibacterialactivities[6,,antitumor7]activity[8],hypotensiveeffect[9],antiproliferationef-fect[10],etc.Thetitlecompoundbearingabenzo-pyranstructuraluni… 相似文献
996.
997.
An enhancive synthesis of (±)-1β, 11-diol-4-en-eudesmol,starting from 2-chloroacrylonitrile, is described. The effect oftemperature on the Diels-Alder reaction of 2-chloroacrylonitrilewith 2-methylfuran and the condition of cationic cyclization ofdiene were discussed in detail. 相似文献
998.
A new Λ type pyriding iodide was synthesized by reaction of 4-picoline and methyl diiodide. The structure was characterized by elemental analysis, IR, UV and TG. The crystal structure of the title compound was determined by X-ray single crystal diffraction. The crystal belongs to monoclinic with space group C2/c, a=18.812(4)?, b=8.7816(6)?, c=10.3165(12)?, β=93.71(1), V=1700.7(4)?3, Z=4. In the molecule, two 4-picoline molecules are bonded by -CH2 group to form Λ type pyridine salt. CCDC: 180871. 相似文献
999.
Price WJ Kuo PK Lee TR Colorado R Ying ZC Liu GY 《Langmuir : the ACS journal of surfaces and colloids》2005,21(18):8422-8428
Nanostructures of self-assembled monolayers (SAMs) are designed and produced using coadsorption and nanografting techniques. Because the structures of these artificially engineered domains are predesigned and well-characterized, a systematic investigation is possible to study the mechanical responses to force modulation under atomic force microscope tips. Force modulation imaging reveals characteristic contrast sensitivity to changes in molecular-level packing, molecule chain lengths, domain boundaries, and surface chemical functionalities in SAMs. By means of actively tuning the driving frequency, the resonances at the tip-surface contact are selectively activated. Therefore, specific surface features, such as the edges of the domains and nanostructures or desired chemical functionalities, can be selectively enhanced in the amplitude images. These observations provide a new and active approach in materials characterization and the study of nanotribology using atomic force microscopy. 相似文献
1000.
The title compound, {[Cu(2,2'-bipy)(C7H4O5S)(H2O)2](H2O}n (2,2'-bipy = 2,2'- bipyridine), was synthesized by the hydrothermal reaction of Cu(NO3)2(3H2O, 2,2'-bipyridine and 2-sulphobenzoic acid, and structurally characterized by single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P with a = 9.21(3), b = 10.17(3), c = 10.77(3) (A), α = 77.017(16), β = 89.80(8), γ = 68.46(7)°, V = 911(5) (A)3, Z = 2, (D/s)max = 0.001, Mr = 473.94, Dc = 1.728 g/cm3, μ(MoKα) = 1.365 mm-1, F(000) = 486, the final R = 0.0246 and wR = 0.0628 for 3809 observed reflections with I > 2σ(I). The mononuclear crystal structure extends into a two-dimensional net- work via hydrogen-bonding interactions and a three-dimensional framework is further formed by means of π-π stacking interactions. 相似文献