聚合物硼氢阴离子还原剂的制备及其对酯的还原研究

氯型季我安盐型强碱性阴离子交换树脂７１１＾＃与硼氢化钾反应制得聚合物硼氢阴离子还原剂，树脂容量３．２ｍｍｏｌ ＢＨ４／ｇ。用于不同酯化合物的还原，操作简便，树脂可再生重复使用。     

Palladium-catalyzed cascade allylation/carbopalladation/cross coupling: a novel three-component reaction for the synthesis of 3,3-disubstituted-2,3-dihydrobenzofurans

A novel one-pot palladium-catalyzed cascade between 2-iodophenol, methyl bromomethylacrylate and an arylboronic acid provides an efficient access to heterocycles possessing the 3,3-disubstituted-2,3-dihydrobenzofuran skeleton via allylation/carbopalladation/Suzuki cross-coupling.     

Oxidation of Styrene with Molecular Oxygen in Supercritical CO2

The oxidation of styrene with molecular oxygen catalyzed by PdCl2 CuCl2 has been investigated in supercritical CO2 with a batch reactor. The oxidative system of styrene contains four components at the beginning and seven components during the reaction. The critical temperature, critical pressure, and critical density at different conversions are determined by using a high-pressure view cell. The effect of phase behavior on the conversion and selectivity were studied. Experimental results showed that the critical parameters of the reaction mixture at fixed initial molar ratio changed with the conversion of reactant. The conversion of styrene reached maximum near the critical density of the reaction mixture. Product selectivity also varied with density of reaction mixture and could be tuned to some degree.     

Efficient degradation of dye pollutants using dioxygen mediated by iron(Ⅱ) 2,2''-bipyridine loaded layered clay catalyst under visible irradiation

The organic-inorganic layered solid catalyst Fe(bpy)32+-laponite was able to photodegrade Rhodamine B (RhB) by activation of dioxygen under visible irradiation (λ＞420 nm), while the homogeneous aqueous solution Fe(bpy)32+ showed no photoactivity. The catalyst could be repeatedly used and retained its reactivity. The hybrid catalyst could be separated from the suspension by centrifugation or sedimentation. The TOC removal yield of RhB was measured. Reactive oxygen species (ROS) formed during degradation was detected by EPR. A possible mechanism was proposed on the basis of the experimental results.     

Catalytic Conversion of 2-Naphthol to 2-Hydroxy-1,4-naphthoquinone Under Mild Conditions

Introduction 2-Hydroxy-1,4-naphthoquinone (HNQ), existing in natural plants,1,2 is popularly separated and purified as dye or pigment. Recent research results show that, with the function to prevent the formation of protein coenzyme of HIV-I, HNQ can inhibit HIV virus from copying and propagating,3,4 HNQs derivatives and di-chloroallyl lawsone are also the inhibitor for RNA syn-thesis of cancer.5 It is well known that there is a rela-tionship between the side chain attached to HNQ an…     

镍钴复合氧化物的制备和析氧活性

用浸碱热分解法制备了具有较高析氧活性和稳定性的复合氧化物ＮｉＣｏ＿２Ｏ＿４。考察了涂液成分、热分解温度和涂覆次数对ＮｉＣｏ＿２Ｏ＿４析氧活性的影响；测定了氧在ＮｉＣｏ＿２Ｏ＿４从电极上的稳态电化学行为。     

Increased oxygen transfer in a yeast fermentation using a microbubble dispersion

A microbubble dispersion (MBD) was used to supply oxygen for aerobic fermentations in a standard 2 L stirred tank fermenter. The microbubble dispersion was formed using only surfactants produced naturally. Growth rates ofSaccharomyces cerevisiae cultures were found to be equal or greater with MBD sparging than with gas sparging. The oxygen transfer coefficent with MBD sparging was found to be 190/h and independent of impeller speed from 100–580 rpm. The oxygen transfer coefficient with air sparging rose from 55 to 132/h over the same range of impeller speeds. Power requirements for the fermenter systems were estimated.     

Competitive Complexation of Lanthanide Cations by Xylitol and Nitrate Anion in Aqueous Solution: A Microcalorimetric Investigation

The apparent equilibrium constants and enthalpies of complexation of Nd³⁺, Sm³⁺, Eu³⁺, and Gd³⁺ by xylitol in aqueous solutions containing NaNO₃ at an ionic strength of 2.0 mol-kg^–1 have been determined by microcalorimetry at 25°C. Since nitrate anion weakly complexes the lanthanide cations, these values are analyzed in terms of competition between xylitol and NO ₃ ^- The method leads to the apparent equilibrium constants and enthalpies of complexation of the lanthanide cations by NO ₃ ^- at this particular ionic strength. Despite the difficulties encountered in characterizing rather weak associations, the results are, whenever comparison is possible, in good agreement with those obtained by direct microcalorimetry. The advantage of this competition method is that it can be used when the enthalpic effects are too weak and insufficiently concentration dependent for direct microcalorimetric determination. In the present case, it allows us to thermodynamically characterize the formation of SmNO ₃ ²⁺ and EuNO ₃ ²⁺ , processes we have not been able to study directly.     

Studies of poly-<Emphasis Type="Italic">L</Emphasis>-lysine-starch nanoparticle preparation and its application as gene carrier

Anion starch nanoparticle (StNP) with a diameter of 50 nm was prepared in water-in-oil microemulsion, with soluble starch as raw materials and POCl₃ as crosslinking agent. PLL-StNP was prepared by linking poly-L-lysine (PLL) on the surface of StNP. At the same time, the size of PLL-StNP and its stability in aqueous solution were checked by AFM. The analysis of plasmid DNA binding, DNase I enzymatic degradation, toxicity and transfection were done. We discovered that PLL-StNP may be used as non-virus nanoparticle gene carrier. And we developed the method of preparing PLL-StNP gene carrier and used it in cell transfection. As non-virus gene carrier, PLL-StNP has some advantages, such as large load of DNA, high transfection efficiency, low cell toxicity and biodegradability.     

Effect of carbonate incorporation on the structural and superconducting properties of the double chain compound Y2Ba4Cu7O15−x

Structural investigations on powder samples of Y₂Ba₄Cu₇O_15–x with different carbonate content have been performed. Powder x-ray Rietveld refinements showed the remarkable influence of carbonate incorporation on the lattice parameters. Most important is the decrease of T_c with increasing carbonate content. We assign these effects to an incorporation of the carbonate ion into the crystal lattice, copper vacancies at the Cu(1) position and a possible misorientation of the copper oxygen single chains. No change of the structure (e. g. superstructure) could be found.