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931.
采用浸渍法,制备了用于合成吲哚的Cu/SiO2催化剂,研究了不同载体和活性组分Cu对苯胺和乙二醇一步合成吲哚反应的催化活性,发现γ-Al2O3、活性炭、Na-Y,SiO2-MgO、MCM41、SiO26种载体中,SiO2是最好的载体;催化剂活性组分Cu含量为0.78mmol/gSiO2时,吲哚的收率高达88%,考察了水蒸汽、氢气、反应温度及接触时间等因素对反应性能的影响,并对催化剂进行了TG测试,得到了Cu/Sio2催化剂催化合成吲哚适应反应条件。 相似文献
932.
Ti2(OMe)4/SiO2催化剂的制备及其合成碳酸二甲酯的反应性能 总被引:4,自引:2,他引:4
采用表面改性和离子交换法制备了SiO2负载的Ti2(OMe)4双核桥联配合物催化剂,用IR、TPD和微反技术考察了催化剂的表面构造及CO2和CH3OH在催化剂表面上的化学吸附和反应性能。结果表明:双核桥联配合物Ti2(OMe)4以Ti-O-Si键锚定在SiO2表面上;CO2在催化剂表面存在桥式和甲氧碳酸酯基两种吸附态,其中甲氧碳酸酯基吸附态是生成DMC的关键物种;CH3OH在催化剂上只有一种分子吸附态。在150℃以下,CO2和CH3OH在Ti2(OMe)4/SiO2催化剂表面上高选择地生成碳酸二甲酯。 相似文献
933.
934.
用光电流作用谱、光电流-电势图等光电化学方法研究了ITO(铟锡氧化物导电玻璃)/TiO2 /Q-PbS(量子点PbS)膜电极的光电转换性质。结果表明,由于量子尺寸的效应,在膜电极制备中,随着ITO/TiO2电极在饱和Pb(CH3COO)2溶液中浸泡时间的不同,所制备的Q-PbS颗粒大小不同,禁带宽度随着浸泡时间的增大而减小,浸泡时间为40 s、在80 ℃烘干下制备的Q-PbS的禁带宽度为1.68 eV,其价带位置为-5.072 eV。Q-PbS修饰ITO/TiO2电极可使光电流发生明显的红移,从而提高宽禁带半导体的光电转换效率。 相似文献
935.
936.
937.
The semiconductor properties of the interface TiO2/electrolyte in high organized porous oxide structures were analyzed by means of impedance spectroscopy near the flat band
potential. The impedance and capacitance studies performed on the as-anodized and thermally treated samples (anatase) indicate
the presence of a duplex structure formed by (1) the oxide at the bottom of the pores and (2) the walls of pores with different
donor densities and surface state concentrations. 相似文献
938.
This study aims to clarify the effects of carbon activation type and physical form on the extent of adsorption capacity and
desorption capacity of a bi-solute mixture of phenol and 2-chlorophenol (2-CP). For this purpose, two different PACs; thermally
activated Norit SA4 and chemically activated Norit CA1, and their granular countertypes with similar physical characteristics,
thermally activated Norit PKDA and chemically activated Norit CAgran, were used. The thermally activated carbons were better
adsorbers for phenol and 2-CP compared with chemically activated carbons, but adsorption was more reversible in the latter
case. 2-CP was adsorbed preferentially by each type of activated carbon, but adsorption of phenol was strongly suppressed
in the presence of 2-CP. The simplified ideal adsorbed solution (SIAS) model underestimated the 2-CP loadings and overestimated
the phenol loadings. However, the improved and modified forms of the SIAS model could better predict the competitive adsorption.
The type of carbon activation was decisive in the application of these models. For each activated carbon type, phenol was
desorbed more readily in the bi-solute case, but desorption of 2-CP was less compared with single-solute. This was attributed
to higher energies of 2-CP adsorption. 相似文献
939.
S. N. Dmitrieva N. I. Sidorenko A. I. Vedernikov L. G. Kuz’mina J. A. K. Howard T. M. Buslaeva S. P. Gromov 《Russian Chemical Bulletin》2007,56(5):993-1002
The condensation reaction of 1,2-bis(2-haloethoxy)-4-nitrobenzenes with acyclic α,ω-(oxa)alkanedithiols in the presence of
alkali metal carbonates produced a series of nitrobenzodithiacrown ethers with macrocycles of different size. The structures
of three ethers were established by X-ray diffraction. A new method was developed for the synthesis of nitrobenzomonothia-15-crown-5
ether. Nitro derivatives of benzodithiacrown ethers were tested as reagents for extraction of palladium(II), platinum(IV), and rhodium(III) from hydrochloric acid solutions. Extraction of PdII salts was found to be highly selective compared to that of PtIV and RhIII salts. Benzodithia-15-crown-5 ether is the most efficient extractant for palladium(II). Reduction of nitrobenzothiacrown ethers with hydrazine hydrate in the presence of a platinum catalyst afforded their amino
derivatives.
Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 958–966, May, 2007. 相似文献
940.
Uwe EilitzChristoph Böttcher Lothar HennigAlois Haas Cecile BoyerKlaus Burger 《Journal of fluorine chemistry》2002,115(2):149-154
Homochiral 2-C-perfluoroalkyl substituted d- and l-riboses were synthesized via Barbier, Grignard and Ruppert type reactions. The influence of the size of the perfluoroalkyl groups, attached to C-2, on the furanose/pyranose as well as on the α-furanose/β-furanose and α-pyranose/β-pyranose ratio in solution was studied. 相似文献