加料方式对CuO/ZnO/Al2O3系催化剂前驱体性质的影响

用XRD、TG-DTG、TPR技术研究了不同加料方式对CuO/ZnO/Al2O3系催化剂前驱体物相组成及其结晶情况的影响，用加压微反装置考察了催化剂合成甲醇反应活性。结果表明, 加料方式对Cu2+形成的中间化合物的物相组成及结晶度影响显著,对Zn2+及Al3+的沉淀物相的影响很小。不同加料方式对催化剂前驱体物相组成及催化剂性能的影响主要是形成的初始前驱体中Cu的物相及结晶度不同。正加法主要形成Cu2(OH)3NO3,并流法主要形成无定形Cu2CO3(OH)2,后者与Zn5(CO3)2(OH)6相互作用转化为(Cu,Zn)2CO3(OH)2和（Cu,Zn）5(CO3)2(OH)6，由它们分解形成的CuO-ZnO固溶体是合成甲醇反应的活性相。并流法能最大程度的形成CuO-ZnO固溶体，有利于CuO粒子的细化，其催化活性较好。     

Synthesis of new tetrazene（N-N=N-N）-linked bi（1,2,4-triazole）

The reaction of 4-amino-1,2,4-triazole with sodium dichloroisocyanurate (SDCI) afforded new tetrazene(N-N=N-N)-linked bi(1.2,4-triazole) 2a in excellent yield.Increasing the molar ratio of SDCI to 4-amino-1,2,4-triazole,the chlorinated product 1,5,5′- trichloro-4,4′-azo-1,2,4-triazole (2b) was formed.These new compounds have been characterized by MS,~1H NMR,~(13)C NMR,and elemental analysis.     

Effects of Calcination Temperature on the Acidity and Catalytic Performances of HZSM-5 Zeolite Catalysts for the Catalytic Cracking of n-Butane

The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 ℃, respectively. The results indicated that the total acid amounts, their density and the amount of B-type acid of HZSM-5 catalysts rapidly decreased, while the amounts of L-type acid had almost no change and thus the ratio of L/B was obviously enhanced with the increase of calcination temperature (excluding 800 ℃). The catalytic performances of modified HZSM-5 catalysts for the cracking of n-butane were also investigated. The main properties of these catalysts were characterized by means of XRD, N2 adsorption at low temperature, NH3-TPD, FTIR of pyridine adsorption and BET surface area measurements. The results showed that HZSM-5 zeolite pretreated at 800 ℃ had very low catalytic activity for n-butane cracking. In the calcination temperature range of 500-700 ℃, the total selectivity to olefins, propylene and butene were increased with the increase of calcination temperature, while, the selectivity for arene decreased with the calcination temperature.The HZSM-5 zeolite calcined at 700 ℃ produced light olefins with high yield, at the reaction temperature of 650 ℃ the yields of total olefins and ethylene were 52.8% and 29.4%, respectively. Besides, the more important role is that high calcination temperature treatment improved the duration stability of HZSM-5zeolites. The effect of calcination temperature on the physico-chemical properties and catalytic performance of HZSM-5 for cracking of n-butane was explored. It was found that the calcination temperature had large effects on the surface area, crystallinity and acid properties of HZSM-5 catalyst, which further affected the catalytic performance for n-butane cracking.     

Electrochemical Behavior and Determination of Uric Acid at Single-Walled Carbon Nanotube Modified Gold Electrodes

The voltammetric behavior of uric acid was studied at a single-walled carbon nanotube (SWNT) modified gold electrode. Uric acid can effectively accumulate at this electrode and produce an anodic peak at about 0.45 V (vs. SCE) in pH 5.0 sodium acetate buffer solutions (HAc-NaAc). The experimental parameters, such as solution pH, accumulation time, and amount of SWNT, were optimized for determination. Under the optimum conditions, the anodic peak current is linear to the uric acid concentration over the range of 1.0×10⁻⁷ M to 2.5×10⁻⁵ M with a correlation coefficient of 0.998. The detection limit was 5.0×10⁻⁸ M for 60 s accumulation. The electrode could be easily regenerated and exhibited good stability. A 5.0×10⁻⁶ M uric acid solution was measured ten times using the same electrode, and the relative standard deviation of the peak current was 1.3%. This method was successfully applied to the determination of uric acid in human urine samples, and the recovery was 97–99%. The feasibility for simultaneous determination of xanthine, ascorbic acid and uric acid was discussed. These species did not interfere with each other in a certain concentration range. The influence of some surfactants on the anodic peak was also examined.     

An unprecedented 8-fold interpenetrating diamondoid-like coordination polymer containing a Cu+(4)(RCO2)(4) cluster as connecting node

The reaction of Cu(I)(CH(3)CN)(4)BF(4) with 4-pyridylacrylic acid (4-HPYA) affords an unprecedented 8-fold interpenetrating diamondoid-like coordination polymer network [Cu(I)(3)(4-PYA)(2)(H(2)O)(BF(4)) ] (1) with a Cu(+)(4)(CO(2))(4) cluster as connecting node. The interpenetration in metal coordination polymers is the highest degree ever found within diamondoid nets containing a cluster as connecting note. Its fluorescent property was also reported.     

Sensitive Voltammetric Response of p‐Nitroaniline on Single‐Wall Carbon Nanotube‐Ionic Liquid Gel Modified Glassy Carbon Electrodes

An ionic liquid (i.e., 1‐butyl‐3‐methylimidazolium hexafluorophosphate, BMIMPF₆)‐single‐walled carbon nanotube (SWNT) gel modified glassy carbon electrode (BMIMPF₆‐SWNT/GCE) is fabricated. At it the voltammetric behavior and determination of p‐nitroaniline (PNA) is explored. PNA can exhibit a sensitive cathodic peak at ?0.70 V (vs. SCE) in pH 7.0 phosphate buffer solution on the electrode, resulting from the irreversible reduction of PNA. Under the optimized conditions, the peak current is linear to PNA concentration over the range of 1.0×10^?8–7.0×10^?6 M, and the detection limit is 8.0×10^?9 M. The electrode can be regenerated by successive potential scan in a blank solution for about 5 times and exhibits good reproducibility. Meanwhile, the feasibility to determine other nitroaromatic compounds (NACs) with the modified electrode is also tested. It is found that the NACs studied (i.e., p‐nitroaniline, p‐nitrophenol, o‐nitrophenol, m‐nitrophenol, p‐nitrobenzoic acid, and nitrobenzene) can all cause sensitive cathodic peaks under the conditions, but their peak potentials and peak currents are different to some extent. Their peak currents and concentrations show linear relationships in concentration ranges with about 3 orders of magnitude. The detection limits are 8.0×10^?9 M for p‐nitroaniline, 2.0×10^?9 M for p‐nitrophenol, 5.0×10^?9 M for o‐nitrophenol, 5.0×10^?9 M for m‐nitrophenol, 2.0×10^?8 M for p‐nitrobenzoic acid and 8.0×10^?9 M for nitrobenzene respectively. The BMIMPF₆‐SWNT/GCE is applied to the determination of NACs in lake water.     

DABCO-catalyzed reactions of hydrazones with activated olefins

This paper describes several highly efficient DABCO-catalyzed aza-Michael addition reactions of hydrazones to activated olefins. In most cases, these aza-Michael addition reactions gave the corresponding products in high yields under mild conditions. The plausible reaction mechanism is discussed on the basis of deuterium labeling experiments. Upon treatment with HCl, the corresponding cyclized products can be obtained in high yields from the Michael addition products.     

Applications of homemade kit in mutation detection of genes

With the accomplishment of Human Genome Project (HGP), single nucleotide polymorphism (SNP) and mutation detection in human genome are becom-ing a new researching focus. These researches can help us to understand the phenotype diversity of indi-vidual, disease susceptibility and drug resistance of different colonies. Traditional method used for muta-tion detection is slab gel electrophoresis, which re-mains labor-intensive and time-consuming because of the requirement of radioactivity or te…     

Determination of Dopamine in the Presence of Ascorbic Acid Using a Poly(Amidosulfonic Acid) Modified Glassy Carbon Electrode

A glassy carbon electrode (GCE) was modified with electropolymerized films of amidosulfonic acid in pH 7.0 phosphate buffer solution (PBS) by cyclic voltammetry (CV). The modified electrode showed an excellent electrocatalytical effect on the oxidation of dopamine (DA). In pH 7.0 PBS, the anodic peak current increased linearly with the concentration of DA in the range of 5.0×10^–7 1.0×10^–4moldm^–3, with a correlation coefficient of 0.9932, and a detection limit (S/N=3) of 1.0× 10^–7moldm^–3. The relative standard deviation of 10 successive scans was 2.5% for 1.0×10^–6moldm^–3 DA. The interference of ascorbic acid (AA) with the determination of DA could be eliminated because of the very distinct attracting interaction between DA cations and the negatively poly(amidosulfonic acid) film in pH 7.0 PBS. The proposed method exhibited good recovery and reproducibility.     

邻位吡啶自由基多通道分解反应的动力学和反应机理研究

Utilizing Gaussian94 program package, all species involved in decomposition reactions of o-pyridyl radical were optimized fully at B3LYP/6-311＋＋G^＊＊ level. Intrinsic reaction coordinate calculations were employed to confirm the connections of the transition states and products, and transition states were ascertained by the number of imaginary frequency （0 or 1）. The reaction mechanism was elucidated by the vibrational mode analysis and electronic population analysis, and the reaction rate constants were calculated with transition state theory.