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911.
Toshiharu Okui Yuriko Saito Tatsuya Okubo Masayoshi Sadakata 《Journal of Sol-Gel Science and Technology》1995,5(2):127-134
Selective gas permeation of porous organic/inorganic hybrid membranes via sol-gel route and its thermal stability are described. Separation performance of the hybrid membrane was improved compared with porous membranes governed by the Knudsen flow, and gas permeability was still much higher than that through nonporous membranes. Additionally, it was shown that these membranes were applicable at higher temperatures than organic membranes.SEM observation demonstrated that the thin membrane was crack-free. Nitrogen physisorption isotherms showed the pore size was in the range of nanometers. Gas permeability through this membrane including phenyl group was in the range of 10–8 [cc(STP) cm/(cm2 s cmHg)] at 25°C. The ratios of O2/N2 and CO2/N2 were 1.5 and 6.0, respectively, showing the permeation was not governed by the Knudsen flow. The permeability decreased as the temperature increased. Furthermore, the specific affinity between gas molecules and surface was observed not only in the permeation data of the hybrid membranes but in the physisorption data. These results suggested that the gas permeation through the hybrid membrane was governed by the surface flow mechanism.Thermal analysis indicated that these functional groups were still stable at higher temperatures. The phenyl group especially remained undamaged even at 400°C. 相似文献
912.
Carvajal MA Alvarez S Novoa JJ 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(9):2117-2132
The nature of intermolecular interactions between dicoordinate Cu(I) ions is analyzed by means of combined theoretical and structural database studies. Energetically stable Cu(I).Cu(I) interactions are only found when the two monomers involved in the interaction are neutral or carry opposite charges, thus allowing us to speak of bonding between the components of the bimolecular aggregate. A perturbative evaluation of the components of the intermolecular interaction energies, by means the IMPT scheme of Stone, indicates that both the Coulombic and dispersion forces are important in determining the Cu(I).Cu(I) bonding interactions, because only a small part of that energy is attributable to Cu.Cu interactions, while a large component results from Cu.ligand interactions. The electrostatic component is the dominant one by far in the interaction between charged monomers, while in the interaction between neutral complexes, the electrostatic component is found to be of the same order of magnitude as the dispersion term. Bimolecular aggregates that have like charges are repulsive by themselves, and their presence in the solid state results from anion.cation interactions with ions external to this aggregate. In these cases, the short-contact Cu.Cu interactions here should be more properly called counterion-mediated Cu.Cu bonds. 相似文献
913.
914.
Raju Ranjith Kumar 《Tetrahedron》2007,63(33):7850-7857
A series of new 2-methyl-11-aryl-4-[(E)-arylmethylidene]-1,2,3,4,11,11a-hexahydropyrido[3,4-c][1,5]benzothiazepines were obtained by the reaction of o-aminothiophenol and (E)-1-methyl-3,5-bis(arylidene)-4-piperidones in the presence of a catalytic amount of acetic acid under solvent-free microwave irradiation. These dipolarophiles undergo a highly atom economic 1,3-dipolar cycloaddition with nitrile oxide to afford a series of novel 6-methyl-1-phenyl-8-aryl-4-[(E)-arylmethylidene]-4,5,6,7,7a,8-hexahydro[1,2,4]oxadiazolo[5,4-d]pyrido[3,4-c][1,5]benzothiazepines stereoselectively. 相似文献
915.
N. M. Bogdanovich V. P. Gorelov V. B. Balakireva T. A. Demyanenko 《Russian Journal of Electrochemistry》2005,41(5):576-581
The phase composition and electroconduction in air of solid electrolytes (Ce0.8Sm0.2)1 − x
CuxO2 − δ (CSCu), where x = 0, 2, 5, 10, and 20 mol % and which are synthesized using the ceramic technology, are studied. Adding an additive of CuO lowers the CSCu sintering temperature by 100– 200°C and leads to the formation of single-phase solid solutions of a fluorite type up to x = 10 mol %. The electroconductivity of the CSCu electrolytes remains practically invariant upon adding up to 5 mol % Cu and equals 0.089–0.095 and 0.017–0.021 S cm−1 at 800 and 600°C. The sintering, adhesion, and electroconductance of composite cathodes based on La0.8Sr0.2MnO3 with 40% CSCu and their electrochemical behavior in air in the temperature interval 900–1000°C on carrying electrolyte Zr0.9Y0.1O1.95 with a CSCu sublayer containing 2 mol % Cu are studied.__________Translated from Elektrokhimiya, Vol. 41, No. 5, 2005, pp. 656–661.Original Russian Text Copyright © 2005 by Bogdanovich, Gorelov, Balakireva, Dem’yanenko. 相似文献
916.
Jacques Barrau Ghassoub Rima Tajani El Amraoui 《Journal of organometallic chemistry》1998,570(2):8645
The reactions of the divalent species (ArO)2M (Ar=2,4,6-[(CH3)2NCH2]3C6H2; M=Ge, Sn) with either Me3SiN3, elemental S8, Se or transition metal complexes M′(CO)n+1 (M′=Fe, n=4; M′=Cr, W; n=5) (Ph3P)2Pt·C2H4 have resulted in the isolation of either the new stable formal metallanimines (ArO)2M=N–SiMe3, germanethione, -selone (ArO)2Ge=E (E=S, Se) (the expected formations of the stannanethione and -selone were not observed), or the (ArO)2M=M′(CO)n, (ArO)2M=Pt(PPh3)2 complexes, respectively. The direct oxidation of the (ArO)2M species with various oxidizing agents led to the formation of the corresponding metalloxanes [(ArO)2M–O–]2. All of the chalcogenido- and transition metal–metal 14 complexes have been physicochemically and chemically characterized. The reactions of the (ArO)2Ge=E (E=S, Se) compounds with 3,5-di-tert-butyl-1,2-benzoquinone produced, by extrusion of sulfur or selenium, the dioxametalloles corresponding to the formal addition of the divalent species (ArO)2M to the benzoquinone. A substitution reaction of chalcogen (S/Se) has been observed permitting to go from germaneselone to germanethione. 相似文献
917.
918.
Donghui Wang Zhengping Hao Daiyun Cheng Xicheng Shi Chun Hu 《Journal of molecular catalysis. A, Chemical》2003,200(1-2):229-238
Composite oxide MOx/Al2O3 supported gold catalysts for low-temperature CO oxidation were prepared and investigated. The presence of transition metal oxide was proved to be beneficial to the improvement of catalytic performance of Au/Al2O3 catalysts for low-temperature CO oxidation. Furthermore, the influence of various pretreatment conditions on Au/MOx/Al2O3 catalysts was studied carefully. The image of TEM showed that gold catalyst with small gold particles only in the form of a fine dispersion exhibited highly catalytic activity. The XPS, Fourier transform infrared (FTIR) spectroscopy characterization results of Au/FeOx/Al2O3 catalyst showed that gold catalysts having partially oxidized gold species have the best catalytic performance. One possible pathway for CO oxidation on Au/FeOx/Al2O3 catalyst is that the CO adsorbed on gold particles reacts with adsorbed oxygen, which is possible to occur on oxygen vacancies on the support or at the metal–support interface. 相似文献
919.
ZHENG Li-Min FU Yan LIN Jian-Jun XIN Xin-QuanCoordination Chemistry State Key Laboratory Department of Chemistry Nanjing University Nanjing Jiangsu China 《中国化学》1994,12(3):243-247
The solid-solid state reactions of o-aminobenzoic acid with Zn(OAc)2.2H2O, Cu(OAc)2 .H2O, Ni(OAc)2.4H2O and Mn(OAc)2.4H2O result in the formation of corresponding complexes M(OAB)2 (M = Zn(Ⅱ), Cu(Ⅱ), Ni(Ⅱ), Mn(IⅡ)). XRD, IR and elemental analysis methods have been used to characterize the solid products. The activation energies of these reactions, which are calculated from the kinetic data obtained by means of the isothermal electrical conductivity measurement method, have been found to increase in the order: Cu(OAc)2.H2O(37.7 kJ.mol-1)~Mn(OAc)2.4H2O (39.7kJ.mol-1) < Zn(OAc)2.2H2O (56.3 kJ.mol-1) < Ni(OAc)2.4H2O (85.2 kJ.mol-1). The trend is related to their crystal structures. 相似文献
920.
Alvarez-Merino MA Joly JP Carrasco-Marín F Moreno-Castilla C 《Journal of colloid and interface science》2003,260(2):449-453
Intermittent temperature-programmed desorption of ammonia was used to study the strength and population of surface acid sites of tungsten oxide supported on activated carbon pretreated at 350 and 700 degrees C. Catalysts pretreated at 350 degrees C showed two types of surface acid sites and desorption occurred with free readsorption until a temperature of around 300 degrees C was reached. Pretreatment at 700 degrees C produced three different states of ammonia adsorbed on the catalysts and desorption occurred with free readsorption. 相似文献