An attempt on the VOC oxidation using mechanically activated catalyst

A catalytic action of the mechanochemical products of copper hydroxocarbonate with calcium carbonate was investigated in n-butyl alcohol oxidation tests. The solid products of high-energy milling were identified using thermogravimetry supplemented by X-ray diffraction method. It was shown that the mechanical activation induces more effective tested catalyst because it promotes the alcohol conversion at lower temperatures than that unmilled one. This revised version was published online in July 2006 with corrections to the Cover Date.     

Theoretical study on conformational conversion of 1,3-dioxane inside a capsular host

The conformational conversion of 1,3-dioxane guest encapsulated inside a cylindrical capsular host was investigated with PM3 method and single point energies were evaluated by B3LYP method. When entrapped in the capsule, the guest tumbles were slower than that in the free condition. The influences of the inner phase of the capsule on the guest conformational conversion were discussed in detail.     

Asymmetric silyl nitronate cycloadditions with bornane-10,2-sultam derivatives

Asymmetric silyl nitronate cycloadditions with N-acryloyl (2R)-bornane-10,2-sultam, N-acryloyl (2S)-bornane-10,2-sultam, and N-methacryloyl (2R)-bornane-10,2-sultam have been studied. The asymmetric silyl nitronate cycloaddidon/elimination methodology provides a general route for the asymmetric synthesis of 2-isoxazolines.     

A new reaction of aryl aldehydes with aryl acetylenes in the presence of boron trihalides

[reaction: see text]. The reactions of aryl aldehydes with 2 equiv of arylacetylenes in the presence of boron trichloride yield (E,Z)-1,3,5-triaryl-1,5-dichloro-1,4-pentadienes. Reactions carried out in the presence of boron tribromide generate the corresponding (Z,Z)-1,3,5-triaryl-1,5-dibromo-1,4-pentadienes.     

聚丙烯酰胺凝胶结构非均匀性的动态光散射研究

利用动态光散射技术研究了聚丙烯酰胺 (PAAm)凝胶结构的非均匀性 ,分析了PAAm凝胶结构非均匀性的形成原因及凝胶动态光散射的数据处理方法和分析结果的物理意义 .研究结果表明 ,PAAm凝胶中含有动态相关长度 (LC)不同的两相 ,其中 ,LC 为 10～ 2 0nm的区域是聚合物稀疏相 ,LC 为 85nm左右的区域是聚合物密集相 ,两相的不均匀分布形成了PAAm凝胶结构的非均匀性 .分析表明 ,PAAm凝胶存在两相主要是由于单体和交联剂的溶解度存在差异所致 .随交联度增大 ,PAAm凝胶结构的非均匀性显著增强     

光学活性含硅氨基酸的合成

光学纯的硅取代氨基酸是一类非天然的手性氨基酸合成子，在药物，植物保护 剂和精细化学品的合成具有极为广阔的应用前景，其合成方法包括化学不对称合成 及化学合成外消旋体－生物学拆分两种，综述了该方面的研究进展。     

Polyesters containing ring units in main chains. I. Preparation and stereochemistry of monomers and polyesters

Cycloalkanone (C₅–C₈, C₁₂, and C₁₅) or cycloalkane (C₅ and C₆) ring-containing monomeric diesters and the polyesters derived from them were prepared, and their configurations were studied by ¹³C-NMR spectroscopy. Absolute configurations were determined for ring sizes 5, 6, and 7. Configurational change during reduction of a ketonic group of monomeric diesters with ring sizes 5 and 6 was discussed in terms of the steric effect of ring substituents on the ketonic group. In the polycondensation reaction epimerization of the ring units was observed in 5-, 6-, and 7-membered cycloalkanones and not in others, which is explained by steric hindrance by the ring substituents against attack of tetrabutyl titanate catalyst on the ketonic group.     

2,3,7‐Triazabicyclo[3.3.0]octenes Prepared by Tandem Cascade Reaction of Allyl Azides and Olefinic Dipolarophiles

Tandem cascade reactions of allylazides and olefinic dipolarophiles to give cis‐fused 2,3,7‐triazabicyclo [3.3.0]octenes ( 5, 6 or 7 ) are reported. Therein, an intermolecular dipolar cycloaddition of azide and alkene gave a triazoline which was followed by isomerization of the triazoline to a diazoester ( 4 ) and then an intramolecular dipolar cycloaddition from the diazo functional group and the double bond in 4 to give 5 . Compound 5 may further more undergo a Michael addition to give 7‐substituted‐ 2,3,7‐ triazabicyclo [3.3.0]oct‐2‐ene ( 6 ) or a tautomerization to give 2,3,7‐triazabicyclo[3.3.0]oct‐3‐ene ( 7 ). The reaction may be manipulated to stop at a particular stage by adopting a suit able solvent or an appropriate temperature.     

四川省重点河段水环境安全性评价

为研究四川省重点河段水环境的安全性,利用综合评价指数法和模糊综合评价决策的数学模型对主要水系干流和支流河段的水质安全性做出了评价.结果显示,岷江流域的水质安全性较差,主要的污染物为重金属汞和铁,沱江和涪江流域的水质安全性较好.     

桑色素修饰碳糊电极吸附溶出伏安法测定人尿中痕量铅

制作了用桑色素作修饰剂的碳糊修饰电极 ,利用该电极为工作电极 ,建立了测定痕量铅的新方法。在甲酸钠 盐酸缓冲溶液 (pH 4 .9)中 ,在 - 0 .10V(vs .SCE)下搅拌富集 ,铅 (Ⅱ )与化学修饰碳糊电极表面的桑色素形成电活性络合物而吸附富集于电极表面 ,经 - 0 .85V(vs.SCE)静止还原后 ,阳极化线性扫描 ,在 - 0 .4 3V(vs .SCE)获得一灵敏的二次导数溶出峰。在最佳条件下分别富集 360s和 180s ,其二次导数峰电流与铅 (Ⅱ )浓度分别在 5 .0× 10 - 9～ 1.0× 10 - 7mol·L- 1和 2 0×10 - 8～ 1.0× 10 - 6 mol·L- 1两个范围内呈良好的线性关系 ,富集 6min ,检出限可达 1.0× 10 - 9mol·L- 1(S/N =3)。同时 ,探讨了电极反应机理。方法应用于尿铅测定 ,获得满意的结果