Ti2(OMe)4/SiO2催化剂的制备及其合成碳酸二甲酯的反应性能

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。     

改性Y分子筛的酸碱性能及吸附性能的研究

吡啶、吡咯、苯、甲苯、乙苯作为探针分子，在Li＋, Na＋, K＋, Cs＋改性的Y型分子筛上进行吸附，用TPD及IR方法系统地研究了不同碱金属离子改性的Y型分子筛的酸碱性能和吸附性能的变化. 结果表明，按Li、Na、K、Cs的顺序, 随着碱金属离子半径的增大, 其L酸酸强度依次减弱，L碱的强度逐渐增强.由于改性Y型分子筛所含碱金属离子的不同，其对芳烃的吸附的强弱及吸附量的大小亦不同.随着骨架外的阳离子的半径逐渐增大，碱的强度逐渐增强，与芳烃的作用愈强烈，导致TPD脱附峰温增高及芳烃和侧链上的C－H伸缩振动谱带向低波数位移愈多.由于位阻的原因，对含同一种碱金属离子的分子筛来说，随着芳烃侧链C数的增加，芳烃的吸附量逐渐减小.     

Effect of La_2O_3/γAl_2O_3 Catalyst on the Activation of CH_4 and CO_2 to C_02 Hydrocarbons under Non-equilibrium Plasma

The oxidative coupling of methane (OCM) to C2 hydrocarbons using carbon dioxide as oxidant is an attractive process from environmental point of view. Only a few research papers reported for it1-3. In general, the yield of C2 hydrocarbons was about 6%. This indicated that the method of catalytic activation was unfavorable to the reaction. It is necessary for us to find a new method in order to activate reaction and improve C2 hydrocarbon yield. Non-equilibrium plasma is a cold plasma in…     

An Interesting Approach to Bis-calix[5]arene Analogue from Calix[6]arene

Calix [n] arenas {n = 4, 6 or 8} are easily prepared from formaldehyde and para-substituted phenols via cyclic condensation under alkaline conditions in one step. It is not surprising that the calyx [n] arene (n = 4, 6, 8) chemistry has been developing very rapidly during the latest 20 years1. However, it is not the case for calixarenes with odd benzene rings (for example, n = 5). The yield of p-tert-butylcalix [5] arene synthesized in one-step from p-tert-butylphenol and formaldehyde was a…     

Studies on the Binding Mode of Pinacyanol Chloride to Nucleic Acids

The interaction of pinacyanol chloride(PC) with nucleic acids has been investigated by a series of experiments.Extensive hypochromism,appreciable peak shifts,isosbestic points and new peaks of the product of binding to nucleic acids in the spectra were observed.They showed that the interaction between PC and nucleic acids occurred.The results from absorption spectra of DNA,DNA melting,electrophoresis and fluorescence polarization studies have indicated that PC binds to DNA in nonintercalative way.Consistent with the nonintercalation,the studies of fluorescence titration and absorption titration specified that the binding of PC to nucleic acids occurred by an outside stacking binding,in which nucleic acids served for acting templates,The fact that the new absorption peaks of bound PC at ca,485nm are just close to the absorption bands of Haggregate of PC at high concentrations without DNA further supports the outside stacking binding mode,In addition,other evidence indicated that the interaction between PC and nucleic acids is not purely electrostatic.     

Underpotential Deposition Study and Determination of Bismuth on Gold Electrode by Using Voltammetry

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N-芳亚甲基-4-(4-甲氧基苯基)-5-(1H-1,2,4-三唑-1-基)-1,3-噻唑-2-胺的合成与生物活性

通过2-氨基-4-(4-甲氧基苯基)-5-(1H-1,2,4-三唑-1-基)-1,3-噻唑与取代苯甲醛发生缩合,合成了一系列新型含三唑环的噻唑席夫碱类化合物.利用1H NMR和元素分析对所有化合物进行了结构表征.初步的毒性试验表明,部分标题化合物具有一定的抗肿瘤活性.     

Synthesis and Crystal Structure of 3,9-Bis（pyridin-2-yl）-2,4,8,10-tetraoxaspiro[5.5]undecane

The title compound 3,9-bis(pyridin-2-yl)-2,4,8,10-tetraoxaspiro[5.5]undecane 4(C17H18N2O4) has been synthesized by the reaction of 2,2-bis(hydroxymethyl)propane-1,3-diol with pyridine-2-carbaldehyde in the presence of p-toluenesulfonic acid,and characterized by IR,1H-NMR and X-ray single-crystal diffraction.The crystal belongs to monoclinic system,space group C2/c with a = 25.133(2),b = 5.7219(5),c = 21.942(2) ,β = 99.145(2)°,V = 3115.3(5)3,Z = 8,Dc = 1.340 g/cm3,Mr = 314.33,F(000) = 1328,μ = 0.097 mm-1,MoKa radiation(λ = 0.71073),R = 0.0352 and wR = 0.1022 for 2486 observed reflections with I > 2σ(I).X-ray analysis reveals that the two 1,3-dioxane rings passing through the central spiro-C atom both adopt chair conformation.Intermolecular C-H…π,C-H…O and C-H…N weak interactions link the molecules to form a three-dimensional samdwich,which are effective in the stabilization of the crystal structure.     

AFM and fluorescence spectrascopy investigation for disaggregation of existing Aβ fibrils by baicalein

The wavelength for the peak of fluorescence emission of thioflavin T（ThT） was changed from 445 nm to 481 nm when ThT was added in Aβ solution which indicating theβ-sheet structure of Aβ fibril.The significant decrease in the intensity of fluorescence at 481 nm was observed when the baicalein was added in mixed solution of Aβ and ThT,suggesting that the depolymerization of Aβ fibrils happened and there were Aβfibrils left to react with ThT to keep the initial fluorescence intensity.And the existing Aβfibrils are disaggregated by baicalein in a time- and dose-dependent manner.AFM images of the morphologies of the Aβ_1-42 fibrils obviously changed smaller and more dispersive when baicalein added indicating also the depolymerization of Aβ.The results demonstrate a basis for development of a potential herb drug candidate for the treatment of Alzheimer’s disease（AD）.     

固相萃取-气相色谱-质谱法测定饮用水中36种农药残留量

提出了固相萃取-气相色谱-质谱联用法测定饮用水中36种农药的残留量。样品用石墨化碳/氨基复合型小柱净化和富集后,经DB-1701P弹性石英毛细管柱分离,用电子轰击离子源及选择离子监测扫描模式进行质谱测定。36种农药在一定浓度范围内呈线性关系,检出限(3S/N)在0.001 3～0.070mg.L-1之间。按方法在水样的基础上加入农药混合标准溶液做回收试验,测得回收率在90.8%～112.4%之间,测定值的相对标准偏差(n=5)在3.20%～13.2%之间。