轻烃芳构化的系统研究(Ⅰ)——混合碳四和正己烷在ZnNi/HZSM-5催化剂上的微波芳构化

研究了混合碳四、正己烷在微波条件下，在锌和镍双金属改性 Ｈ Ｚ Ｓ Ｍ－ ５ 上芳构化反应，考察了反应温度和反应时间对气液相产物分布的影响并与常规加热作了比较，详细探讨了微波芳构化反应机理。实验结果表明：（１） 在反应温度４００ ℃，质量空速１ ．０ ｈ － １ ，以混合碳四为原料，经微波芳构化和常规加热芳构化实验对比，微波芳构化下的芳烃收率提高约１７ ．０８ ％ ， Ｂ Ｔ Ｘ 选择性远远高于常规加热；（２） 从反应温度对性能影响的考察表明，反应温度变化对微波芳构化反应性能的影响比较大。微波芳构化具有加快反应速率，提高选择性和芳烃收率及降低反应温度等优点，是更好的实现择形催化的好方法。

轻烃芳构化的系统研究(Ⅱ)——ZnNi/HZSM-5催化剂的再生工艺考察

研究了轻烃芳构化 Ｚｎ Ｎｉ／ Ｈ Ｚ Ｓ Ｍ － ５ 催化剂的失 活类型， 认为积炭失活是改性 Ｚ Ｓ Ｍ － ５ 催化剂的最主要失活方式，经烧焦可恢复其催化活性。通过马弗炉 静态烧焦和反应管动态烧 焦， 考察了再生温度对烧焦过程的影响，推测出再生模式。在小型连续式１００ ｍ Ｌ 固定床装置上在宏观热效应方面模拟了工业烧焦再生过程，认为烧焦是一个从外向内逐步扩散的过程，在催化剂上会形成热点，在烧焦再生的影响因素（ 再生气的氧含量、空速，再生最高温度和时间等） 中，再 生最高温度的影响是最显 著的， 只有达到５７５ ℃才能恢复催化剂活性；而再生气空速和氧含量决定了再生时间。在所考察的３ 种再生方案中，确定了最佳的再生方案（ 低起燃温度，一次烧焦） 。该方案不仅比以往 方案省时５０ ％ ，而且 再生后 Ｚｎ Ｎｉ／ Ｈ Ｚ Ｓ Ｍ－ ５ 催化性能恢复好，稳定性不变。

Preparation and electrochemical performance of nano-scale Ni(OH)_2 doped with zinc

Nano-scale Ni（OH）2 doped with Zn was prepared by precipitation transformation method and characterized by XRD and TEM. The electrochemical performance was investigated by cyclic voltammetry （CV） and constant current technology. The measurement results indicate that the lattice parameters of nano-scale Ni（OH）2 are changed and the agglomeration of particles becomes obvious with the increased Zn-doped content. Compared with un-doped one, the discharge specific capacities ofnano-scale Ni（OH）2 doped with 10% Zn are enhanced by 8% and 6%, respectively, at the discharge rate of 0.2C and 3C. After 110 cycles, the discharge specific capacity of the sample doped with 10% zinc is still above 85% of its initial capacity discharged at 0.2C. Therefore, a suitable Zn-doped content is beneficial to improving the discharge performance of nano-scale Ni（OH）2.

Effect of the amount of zinc-doped on the electrochemical performance of nickel hydroxide

The nickel hydroxide prepared by micro-emulsion method was doped by coprecipitated Zn. The effect of the amount of zinc-doped on the properties of Ni(OH)2 such as the reversibility of the electrode reaction, the charge efficiency and active material utilization ratio of nickel electrode, and discharge specific capacity was studied by cyclic voltammetry and constant current charge-discharge tests. The results indicate that the specific discharge capacity of nickel hydroxide obtained by micro-emulsion method is much less than its theoretical value because the transfer of electrons and the diffusion of protons H+ are hindered owing to its crystal grain size in a nanometer range and thus possessing higher crystal interface resistance. The crystal cells are swelled and the crystal defects increased in prepared material due to part of Ni2+ substituted by Zn2+ when zinc and nickel hydroxide are coprecipitated. Hence, the electrons and protons H+ in the electrode reaction are transferred easily, the electrochemical behavior of nickel electrode is improved and discharge specific capacity is promoted. However, the performance of Ni(OH)2 is gradually enhanced with the addition of zinc-doped at first, while slowly decreased after the content of zinc is added to a certain value. The best electrode reaction reversibility, the highest electrode charge efficiency, the highest active material utilization ratio and the largest specific capacity on discharge are available when the mass fraction of Zn doped in nickel hydroxide by coprecipitation reaches 2.5 %.

Influence of Chemical Effect on the Kβ/Kα Intensity Ratios and Kβ Energy Shift of Co, Ni, Cu, and Zn Complexes

Chemical effects on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes were investigated. The samples were excited by 59.5 keV γ-rays from a ^241Am annular radioactive source. K X-rays emitted by samples were counted by an Ultra-LEGe detector with a resolution of 150 eV at 5.9 keV. We observed the effects of different ligands on the Kβ/Kα intensity ratios and △E energy differences for Co, Ni, Cu, and Zn complexes. We tried to investigate chemical effects on central atoms using the behaviors of different ligands in these complexes. The experimental values of Kβ/Kα were compared with the theoretical and other experimental values of pure Co, Ni, Cu, and Zn.

Kinetics of Vapor-Phase Carbonylation of Ethanol on Ni-Zn/C Catalyst

A novel heterogeneous Ni-Zn/C catalyst was used for vapor-phasecarbonylation of ethanol under at- mospheric pressure. Experimentswere designed with the elimination of mass-transfer resistances. Thedata of primary reactions in the carbonylation were collected with adifferential tubular reactor. Power law rate models were employed toexpress the conversion of ethanol and the yields of ethyl propionateand diethyl ether. The results obtained with the models were inagreement with the experimental data.

Electroless Co-Zn Surface-Modified Nickel Hydroxide as an Active Material for Pasted Nickel Electrodes

Chemically precipitated β type nickel hydroxide powder was surface modified by electroless deposition of Co Zn coatings,and physical properties of both the modified and unmodified nickel hydroxide were characterized by scanning electron microscopy (SEM), specific surface area (BET), X ray diffraction (XRD) and X ray photoelectron spectroscopy (XPS). It has been found that Co and Zn components of the surface electroless coatings exist in the oxidized state. Electrochemical performances of pasted nickel electrodes using the modified nickel hydroxide as an active material were investigated, and compared with those of the electrodes prepared with the unmodified nickel hydroxide. Charge/discharge tests show that the modified nickel hydroxide electrodes exhibit better performances in the charge efficiency, specific discharge capacity and active material utilization. Their resistance to swelling with cycling is also superior to that of the unmodified nickel hydroxide electrodes. Cyclic voltammetric (CV) studies indicate that the modified electrodes have a higher electrochemical activity, and the porous pasted nickel electrodes have some distinguished CV characteristics in comparison with those of the thin film nickel electrodes.

Effects of dispersant on performance of Ni-Zn batteries

A new additive of sodium hexametaphosphate （SHMP） was introduced to the paste of zinc electrode, with the purpose of preventing the zinc active materials from agglomerating and improving the stability of batteries. The properties of the zinc electrodes were characterized by scanning electron microscopy （SEM）, constant current charge/discharge measurement, self-discharge test and hydrogen collection experiment. The photographs of zinc electrode show that SHMP can significantly break up the agglomeration, uniforrnize the particle distribution and increase the surface area, which are advantageous to improve the electrochemical performance of zinc electrode. The experimental battery shows a 97 times cycling life and a 30.2% remaining capacity after 4 d storage. The hydrogen collection experimental results indicate that the SHMP can decrease the ratio of hydrogen evolution. Therefore, the corrosion of zinc electrode is suppressed and the charge/discharge efficiency is enhanced.

Effect of Mixed Oxide Support for Ni/ZnO in Reactive Adsorption Desulfurization

The effect of mixed oxide support on the performance of Ni/ZnO in the reactive adsorption desulfurization(RADS) reaction was investigated in a fixed bed reactor by using thiophene as the sulfur-containing compound in the model gasoline. A series of oxide supports for Ni/ZnO were synthesized by the co-precipitation method and characterized by XRD, N_2-adsorption, TPR and NH_3-TPD techniques. It was found that the desulfurization capacity of Ni/ZnO was enhanced greatly when active components were supported on the proper mixed oxide. Ni/ZnO supported on oxides exhibited much higher desulfurization efficiency and sulfur adsorption capacity than the unsupported Ni/ZnO and the synthesized Ni/ZnO-SA adsorbent exhibited the highest efficiency for thiophene removal. The higher desulfurization activity and sulfur capacity of Ni/ZnO supported on SiO_2-Al_2O_3 with small particle size, high specific surface area and large pore volume could promote the high dispersion of active metal phase and the transfer of sulfur to ZnO with lower mass transfer resistance. γ-Al_2O_3 species could weaken the interaction of active phases and SiO_2 as well as could increase greatly the amount of weak acids. Therefore, these oxides could impose a great influence on the structure and chemical properties of the catalyst.

Synthesis and crystal structure of nickel(Ⅱ) and zinc(Ⅱ) complexes with 2,4-bis(3,5-dimethylpyrazol-l-yl)-6-methoxyl-1,3,5-triazine

2,4-Bis(3,5-dimethylpyrazol-1-yl)-6-methoxyl-1,3,5-triazine(bpt) has been synthesized by using a new, simple and general method with high yields. Reactions of bpt with Ni(ClO4)2·6H2O and Zn(ClO4)2·6H2O in methanol gave mononuclear complex [Ni(bpt)2]· (ClO4)2·H2O and ternary complex [Zn(mpt)2(dmp)](ClO4)2 respectively, where mpt (2,4-dimethoxy-6-(3,5-dimethyl- pyrazol-1-yl)-1,3,5-triazine) and dmp(3,5-dimethylpyrazole) are the alcoholysis products of bpt in the presence of Zn2+ ion. A possible mechanism for this catalytic reaction was proposed. X-ray crystal structure for ligand bpt, Ni and Zn complexes are reported. The protonated form of the ligand bpt crystallizes as its perchlorate salt including one molecule of water, [Hbpt·H2O·ClO4]. The proton is located on one pyrazole N-atom. [Hbpt·H2O·ClO4], in which [Hbpt]+ is in cis-cis conformation, are packed in slipped stacks of approximately parallel layers. The Π -Π overlap interactions between the non-protonized pyrazoles of the adjacent layers give a zigzag arrangement of the planar aromatic [Hbpt]+ molecules. In [Ni(bpt)2](ClO4)2·H2O, bpt are meridionally three-coordinated with Ni2+. The coordination sphere around Ni2+ is a slightly distorted square bipyramid, where four pyrazole nitrogen atoms occupy the basal positions and two triazine nitrogen atoms the apical one. In [Zn(mpt)2(dmp)](ClO4)2, the Zn atom is coordinated with a pair of bidentate mpt ligands and one monodentate dmp ligand, forming a distorted trigonal bipyramid, where the two triazine nitrogen atoms of mpt and one nitrogen atom of dmp occupy the basal positions, and the two pyrazole nitrogen atoms of mpt the apical one.