等离子发射光谱法测定加氢精制原料油中有机硅化合物中的硅含量

建立了以喷气燃料为稀释剂,用等离子发射光谱仪测定加氢精制原料油中有机硅化合物中微量硅的分析方法,并对该方法的最佳条件进行了探讨。该方法分析精度为4.53％,回收率为101.0％～107.8％。

Fabrication and characterization of tungsten-containing mesoporous silica for heterogeneous oxidative desulfurization

A series of functional,tungsten-containing mesoporous silica materials（W-SiO2） have been fabricated directly from an ionic liquid that contained imidazole and polyoxometalate,which acted as mesoporous template and metal source respectively.These materials were then characterized through X-ray diffraction（XRD）,transmission electron microscopy（TEM）,Raman spectroscopy,Fourier transform infrared spectra（FTIR）,diffuse reflectance spectra（DRS）,and N2 adsorption-desorption,which were found to contain tungsten species that were effectively dispersed throughout the structure.The as-prepared materials W-SiO2 were also found to possess a mesoporous structure.The pore diameters of the respective sample W-SiO2-20 determined from the TEM images ranged from 2 to 4 nm,which was close to the average pore size determined from the nitrogen desorption isotherm（2.9 nm）.The materials were evaluated as catalysts for the heterogeneous oxidative desulfurization of dibenzothiophene（DBT）,which is able to achieve deep desulfurization within 40 min under the optimal conditions（Catalyst（W-SiO2-20）= 0.01 g,temperature = 60℃,oxidant（H2O2）= 20 μL）.For the removal of different organic sulfur compounds within oil,the ability of the catalyst（W-SiO2-20） under the same conditions to remove sulfur compounds decreased in the order：4,6-dimethyldibenzothiophene Dibenzothiophene Benzothiophene 1-dodecanethiol.Additionally,they did not require organic solvents as an extractant in the heterogeneous oxidative desulfurization process.After seven separate catalytic cycles,the desulfurization efficiency was still as high as 90.3%.From the gas chromatography-mass spectrometer analysis,DBT was entirely oxidized to its corresponding sulfone DBTO2 after reaction.A mechanism for the heterogeneous desulfurization reaction was proposed.

Selenium Distribution Pattern, Antineoplastic and Immunostimulatory Activities of a Novel Organoselenium Compound Eb

Aim To study the distribution pattern, antineoplastic activity and immunocompetence of a novel organoselenium compound Eb and investigate its in vivo antineoplastic potential. Methods Eb was administered to Kunming mice (dosage, 0.1 g·kg^(-1)·d^(-1)) intragastrically for 7 successive days. The contents of selenium in heart, liver, spleen, kidneys, lungs, stomach, brain, muscle, and bone were determined by fluorometric method on the eighth day. MTT assay was used to study tumor growth inhibition of Eb in vitro, and lymphocyte transformation, hemolysin formation and phagocytosis assay were used to study its immunocompetence. Results After 7 days′ administration of Eb, the tissue contents of sele-(nium) in liver, spleen, lungs, kidneys, and bone of mice increased, especially those in liver and spleen increased significan-tly, compared with controls; but no significant changes of such contents were found in muscle, heart, brain, and stomach. Eb demonstrated inhibitory effects on human Bel-7402, BGC-823, and Calu-3 cancer cell lines in vitro. Eb also showed ability to enhance lymphocyte transformation and serum hemolysin formation in vitro and increase the phagocytosis of macrophages. Conclusion The validated antitumor and immunostimulatory activities of Eb suggest a hypothesis that Eb may behave as a biological response modifier when used as an antitumor agent. Eb is worthy of further study in developing a new antineoplastic and immunity enhancing agent in the light of its antitumor activity, immunocompetence and specific distribution in liver, lungs, kidneys, bone, and spleen.

One-pot synthesis of mesosilica/nano covalent organic polymer composites and their synergistic effect in photocatalysis

Organic-inorganic hybrid materials provide a desirable platform for the development of novel functional materials.Here,we report the one-pot synthesis of mesoporous hybrid nanospheres by the in-situ sol-gel condensation of tetraethoxysilane around surfactant micelle-confined nano covalent organic polymer(nanoCOP)colloids.The hybrid nanospheres containing nanoCOPs uniformly distributed in the mesosilica network,inherited the visible light responsive properties of the nanoCOPs.The turnover frequency of the hybrid nanospheres is almost 12 times that of its corresponding bulk COP counterpart for the photocatalytic reductive dehalogenation of a-bromoacetophenone,which is attributed to activation of the Hantzsch ester reductant by the hydroxyl group.The existence of a volcano relationship between the activity and nano COP/mesosilica ratio confirmed the synergistic effect between nano COP and mesosilica.Our preliminary results suggest that hybridization of semiconductors and reactant-activating materials is an efficient strategy for enhancing the activity of a catalyst for photocatalysis.

Synthesis and Crystal Structure of the Polyoxometalatebased Complex [Mn(DMSO)_5H_2O]_2SiMo_(12)O_(40)

A polyoxometalate-based complex [Mn(DMSO)5H2O]2SiMo12O40 has been synthe- sized and it crystallizes in triclinic, space group P with a = 11.863(2), b = 12.750(3), c = 13.255(3) , a = 83.62(3), b = 69.46(3), g = 87.14(3), V = 1865.6(6) 3, Dc = 2.445 g/cm3, Z = 1, ?= 2.660 mm-1, Mr = 2746.56, F(000) = 1328, R = 0.0569, wR = 0.1190 and GOF = 1.125. The results of X-ray crystal analysis and IR spectrum show that there exists strong interaction between the heteropolyanions [SiMo12O40]4- and coordination cations [Mn(DMSO)5H2O]2+ in solid state.

Direct silylation reactions of inert C-H bonds via transition metal catalysis

In the past thirty years,transition metal catalyzed silylation of inert C–H bonds has attracted intensive attention due to the importance and wide use of organosilicon compounds.In this review,the silylation reactions of inert C–H bonds catalyzed by transition metal complexes of Ir,Rh,Ru,Pt,Pd,Ni,and Sc,and the strategies utilized to access the site-selective C–H silylation products have been summarized.Furthermore,the mechanisms of C–H silylation reactions have been discussed briefly.

Nanostructuring gold wires as highly durable nano- catalysts for selective reduction of nitro compounds and azides with organosilanes

A general method is developed to prepare durable hybrid nanocatalysts by nanostructuring the surface of gold wires via simple alloying and dealloying. The resulting nanoporous gold/Au （NPG/Au） wire catalysts possess nanoporous skins with their thicknesses on robust metal wires specified in a highly controllable manner. As a demonstration, the as-obtained NPG/Au was shown to be a highly active, chemo-selective, and recyclable catalyst for the reduction of nitro com- pounds and azides using organosilanes as reducing agents.