乙醇一步合成乙酸乙酯Cu／ZnO／NiO／Al2O3催化剂的催化性能及其表征

乙醇一步合成乙酸乙酯Ｃｕ／ＺｎＯ／ＮｉＯ／Ａｌ２Ｏ３催化剂的催化性能及其表征郑荣辉ａ曾金龙ａ傅锦坤ｂ（ａ．厦门大学化工系ｂ．化学系厦门３６１００５）关键词一步合成法乙酸乙酯混合氧化物催化剂ＴＰＲ和ＴＰＤ中图分类号Ｏ６２３．４２６．２作为重要化工产品的...     

Cu／ZnO／Al_2O_3／ZrO_2催化剂上乙醇脱氢合成乙酸乙酯Ⅰ．催化反应性能及机理

研究了经ＺｒＯ２改性的Ｃｕ／ＺｎＯ／Ａｌ２Ｏ３的催化性能，考察了操作条件、ＺｒＯ２含量及不同原料的影响．发现经共沉淀法制备的Ｃｕ／ＺｎＯ／Ａｌ２Ｏ３／ＺｒＯ２具有最佳的反应活性及选择性．以９５％乙醇为原料，在２６５℃，ＷＨＳＶ１．５ｈ－１时，乙醇转化率为６９．０％，乙酸乙酯选择性为７０．２％．使用无水乙醇为原料要好于９５％乙醇，使用乙醛或醇醛混合原料，亦有乙酸乙酯生成．乙醇在此催化剂上的反应机理为乙醇先在Ｃｕ上脱氢为乙醛，然后乙醛在酸碱双中心上发生Ｃａｎｎｉｚａｒｒｏ反应生成乙酸乙酯．还讨论了ＺｒＯ２的作用及催化剂活性降低的原因     

Cu／ZnO／Al_2O_3／ZrO_2催化剂上乙醇脱氢合成乙酸乙酯Ⅱ．催化剂的表征

采用ＸＲＤ，ＴＰＲ和ＴＰＤ／ＴＰＳＲ方法研究了ＣｕＯ／ＺｎＯ／Ａｌ２Ｏ３／ＺｒＯ２（及还原态）催化剂的物相结构、还原状况、酸碱性质及吸附状况，并与其它催化剂作了比较．ＸＲＤ结果表明，此催化剂在还原前有以晶相存在的ＣｕＯ，还原后以铜晶形式存在，而Ａｌ２Ｏ３，ＺｎＯ，ＺｒＯ２在还原前后均以无定形形式存在．ＴＰＲ实验发现，共沉淀法制备的铜基催化剂只有一个耗氢峰，对应ＣｕＯ的一种分布状态，且催化剂中ＺｒＯ２的存在促进了催化剂的还原．ＮＨ３－ＣＯ２双组分共吸附结果表明，ＣｕＯ／ＺｎＯ／Ａｌ２Ｏ３／ＺｒＯ２催化剂上有两种强度不同的酸中心（１００℃，３４０℃）及弱碱中心（９０℃）．乙醇在催化剂上的ＴＰＳＲ结果表明，在１１０℃有乙醇的脱附峰，氢气及乙醛的生成峰在２１０℃，而在高温时则有ＣＯ，ＣＯ２及丙酮的脱附，整个过程中仅检测到微量乙酸乙酯的脱附（ｍ／ｅ＝４３）     

Cu/ZnO/Al2O3/ZrO2催化剂上乙醇脱氢合成乙酸乙酯Ⅰ.催化反应性能及机理

研究了经ＺｒＯ２改性的Ｃｕ／ＺｎＯ／Ａｌ２Ｏ的催化性能，考察了操作条件，ＺｒＯ２含量及不同原料的影响，发现经共沉淀法制备了Ｃｕ／ＺｎＯ／Ａｌ２Ｏ３／ＺｒＯ２具有最佳的反应活性及选择性以９５％乙醇为原料，在２６５℃，ＷＨＳＶ１．５ｈ＾－１，乙醇转化率为６９．０％，乙酸乙酯选择性为７０．２％，使用无水乙醇为原料要好地９５％乙醇，使用乙醛或醇醛混合原料，亦有乙酸乙酯生成，乙醇在此催化剂上的反应机理为乙醇     

CO2／H2和（CO／CO2）＋H2低压合成甲醇催化过程的本质

通过在Ｃｕ／ＺｎＯ／Ａｌ２Ｏ３催化剂上ＣＯ２＋Ｈ２，ＣＯ＋Ｈ２和（ＣＯ／ＣＯ２）＋Ｈ２催化反应动力学研究对合成甲醇动力学和反应机理进行了细致分析，提出合成甲醇的反应机理，解释了在（ＣＯ／ＣＯ２）＋Ｈ２合成甲醇过程中少量ＣＯ２的作用及合成甲醇的直接碳源。     

制备方法对超细Cu／ZnO／Al2O3催化剂上CO2＋H2合成甲醇的影响

制备方法对超细Ｃｕ／ＺｎＯ／Ａｌ_２Ｏ_３催化剂上ＣＯ_２＋Ｈ_２合成甲醇的影响张玉龙，王欢，邓景发（复旦大学化学系，上海，２００４３３）关键词超细粒子，合成甲醇，Ｃｕ／ＺｎＯ／Ａｌ_２Ｏ_３催化剂，ＣＯ_２＋Ｈ_２ＣＯ２＋Ｈ２合成甲醇是目前的热门课题［１～...     

CuO－ZnO基CO_2／H_2合成甲醇催化剂的反应活性中心

应用ＸＰＳ，ＸＡＥＳ和紫外漫反射光谱法研究了ＣｕＯ－ＺｎＯ／氧化物上ＣＯ２／Ｈ２合成甲醇的反应活性中心．ＣｕＯ－ＺｎＯ／氧化物催化剂上的反应活性中心是存在于ＣｕＯ－ＺｎＯ固溶体中的Ｃｕ－Ｚｎ－Ｏ（＂□＂为氧空位），活性中心的Ｃｕ价态为Ｃｕ－和Ｃｕ０．反应活性中心在ＣｕＯＺｎＯ－ＺｒＯ２催化剂上比在其它ＣｕＯ－ＺｎＯ／氧化物催化剂如ＣｕＯ－ＺｎＯ，ＣｕＯ－ＺｎＯ－ＭｇＯ，ＣｕＯＺｎＯ－Ａｌ２Ｏ３和ＣｕＯ－ＺｎＯ－ｒ２Ｏ３上更加稳定．     

CuO／CeO2和CuO／Al2O3催化剂的催化性能

本文以ＣＯ氧化为模式反应考察了ＣｅＯ２和Ａｌ２Ｏ３负载氧化铜催化剂的氧化活性，运用ＸＲＤ和ＴＰＲ技术研究了催化剂的还原性能和物相结构，结果表明：载体性质对负载ＣｕＯ催化剂的ＣＯ氧化活性有很大影响，ＣｕＯ／ＣｅＯ２催化剂活性明显高于ＣｕＯ／Ａｌ２Ｏ３催化剂．催化剂的还原特性随载体不同而不同．同时发现，热处理对催化剂铜物种的存在形式，晶粒大小、还原特性及其催化活性有明显影响，ＣｕＯ／Ａｌ２Ｏ３催化剂活性下降的主要因素是生成了活性较低的ＣｕＡｌ２Ｏ４相，而ＣｕＯ／ＣｅＯ２催化剂活性下降是由于ＣｕＯ和ＣｅＯ２发生烧结，晶粒变大     

锰助剂对Co／ZrO2超细催化剂F—T合成性能的影响

制备了以气凝胶超细ＺｒＯ２为载体的Ｃｏ／ＺｒＯ２及Ｃｏ－ＭＺｒＯ２催化剂；考察了Ｍｎ助剂对Ｃｏ／ＺｒＯ２催化剂结构、织构１还手、Ｈ２脱附及Ｆ－Ｔ合成性能的影响。结果表明，１５％Ｃｏ－４．７％Ｍｎ／ＺｒＯ２是合成重质烃（Ｃ２）的合适催化剂，每立方米合成气的Ｃ５收率可达１５０ｇ。     

CuO／CeO_2／γ－Al_2O_3催化剂的结构及氧物种

应用ＸＲＤ、ＥＳＲ及ＸＰＳ方法研究了ＣｕＯ／ＣｅＯ２／γ－Ａｌ２Ｏ３催化剂的体相及表面结构，并对催化剂表面氧物种进行了表征．实验结果表明，ＣｅＯ２使Ｃｕ２＋还原为低价钢离子和增加钢化合物的分散性．催化剂中ＣｅＯ２含量高时，表面有Ｏ２－和Ｏ－物种，而ＣｅＯ２含量低时，只有Ｏ２－物种．     

Neue Verbindungen im System CaO/SiO2/CaCl2/H2O

New Compounds in the System CaO/SiO₂/CaCl₂/H₂O The hydrothermal formation of novel calcium silicate hydrates of compositions 5 CaO · 2 SiO₂ · CaCl₂ · 4 H₂O, 5 CaO · 2 SiO₂ · CaCl₂ · 2 H₂O and 4 CaO · 2 SiO₂ · CaCl₂ · H₂O from Ca₃SiO₅ and mixtures of CaO and SiO₂, respectively, in presence of calciumchloride at 200°–350 °C is described. From molybdate-reaction, ²⁹Si MAS NMR, DTA and TG measurements it is concluded that these compounds are based on disilicate anions and are to be interpreted as calcium hydroxide disilicate chlorides.     

The preparation of NbH5(Me2PCH2CH2Me2)2 and NbHL2(Me2PCH2CH2PMe2)2 (L = CO or C2H4)

MMe₅(dmpe) (M = Nb or Ta, dmpe = Me₂PCH₂CH₂PMe₂) reacts with H₂ (500 atm) and dmpe in THF at 60°C to give MH₅(dmpe)_2? NbH₅(dmpe)₂ readily reacts with two mol of CO or ethylene (L) to give NbHL₂(dmpe)₂. The exchange of the hydride ligand with the ethylene protons in NbH(C₂H₄)₂(dmpe)₂ is not rapid on the ¹H NMR time scale (60 MHz) at 95°C.     

Li2O-TiO2-SiO2-P2O5和Li2O-TiO2-Al2O3-P2O5体系锂离子固体电解质的制备及性能研究

一些具有NASICON型网格结构的固体电解质具有高的电导率和好的稳定性,NASICON的意思是Na Super Ionic Conductor[1]。当NaZr2(PO4)3中P5 被Si4 部分取代时便可以得到具有NASICON结构的Na1 xZr2SixP3-xO12体系,其具有高的钠离子电导率。然而有相同结构的Li1 xZr2SixP3-xO12体系的离子电导率却很低,这是因为Li 半径太小,而NASICON三维网格结构的离子通道太大,两者不匹配而使电导率下降[2]。但当LiZr2(PO4)3中Zr4 被离子半径小些的Ti4 取代,所得LiTi2(PO4)3的通道就与Li 半径相匹配,适合于锂离子的迁移,从而使其电导率…     

Formation of [Cp2TiSbMe2]2, [Cp2TiSb(SiMe3)2]2 and [Cp2TiCl]2·2Mes4Sb2

Reactions of [Cp₂Ti(btmsa)] (btmsa = bis(trimethylsilyl)acetylene) with R₄Sb₂ (R = Me, Me₃Si) give [Cp₂TiSbMe₂]₂ (1) or [Cp₂TiSb(SiMe₃)₂]₂ (2) respectively. [Cp₂TiCl]₂·2Mes₄Sb₂ (3) is serendipitously formed from [Cp₂Ti(btmsa)] and Mes₂SbH containing NH₄Cl traces.     

Conversion of NO in NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 Systems by Dielectric Barrier Discharge Plasmas

An experimental study on the conversion of NO in the NO/N₂, NO/O₂/N₂, NO/C₂H₄/N₂ and NO/C₂H₄/O₂/N₂ systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N₂ system, NO decomposition to N₂ and O₂ is the dominating reaction; NO conversion to NO₂ is less significant. O₂ produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O₂ produced decreases at 298 K, but slightly increases at 523 K. In the NO/O₂/N₂ system, NO is mainly oxidized to NO₂, but NO conversion becomes very low at 523 K and over 1.6% of O₂. In the NO/C₂H₄/N₂ system, NO is reduced to N₂ with about the same NO conversion as that in the NO/N₂ system but without NO₂ formation. In the NO/C₂H₄/O₂/N₂ system, the oxidation of NO to NO₂ is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO₂ selectivity in the energy density range of 317–550 J L⁻¹. It finally decreases gradually at high energy density. A negligible amount of N₂O is formed in the above four systems. Of the four systems studied, NO conversion and NO₂ selectivity of the NO/C₂H₄/O₂/N₂ system are the highest, and NO/O₂/C₂H₄/N₂ system has the lowest electrical energy consumption per NO molecule converted.     

KCl-KBO2-K2CO3, K2MoO4-KBO2-K2CO3, and K2WO4-KBO2-K2CO3 ternary systems

phase diagrams of KCl-KBO₂-K₂CO₃, K₂MoO₄-KBO₂-K₂CO₃, and K₂WO₄-KBO₂-K₂CO₃ ternary systems were studied by a calculation-experimental method and differential thermal analysis (DTA). The coordinates of ternary eutectics were determined to be E ₁: 622°C, 8.5 mol % KBO₂, 56.5 mol % KCl, and 35 mol % K₂CO₃; E ₂: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂MoO₄; E ₃: 710°C, 23 mol % KBO₂, 43 mol % K₂CO₃, and 34 mol % K₂WO₄. The specific heats of melting of the eutectics were determined.     

Removal of NO in NO/N2, NO/N2/O2, NO/CH4/N2, and NO/CH4/O2/N2 systems by flowing microwave discharges

In this paper, continuing previous work, we report on experiments carried out to investigate the removal of NO from simulated flue gas in nonthermal plasmas. The plasma-induced decomposition of small concentrations of NO in N2 used as the carrier gas and O2 and CH4 as minority components has been studied in a surface wave discharge induced with a surfatron launcher. The reaction products and efficiency have been monitored by mass spectrometry as a function of the composition of the mixture. NO is effectively decomposed into N2 and O2 even in the presence of O2, provided always that enough CH4 is also present in the mixture. Other majority products of the plasma reactions under these conditions are NH3, CO, and H2. In the absence of O2, decomposition of NO also occurs, although in that case HCN accompanies the other reaction products as a majority component. The plasma for the different reaction mixtures has been characterized by optical emission spectroscopy. Intermediate excited species of NO*, C*, CN*, NH*, and CH* have been monitored depending on the gas mixture. The type of species detected and their evolution with the gas composition are in agreement with the reaction products detected in each case. The observations by mass spectrometry and optical emission spectroscopy are in agreement with the kinetic reaction models available in literature for simple plasma reactions in simple reaction mixtures.     

Formation of nano-crystalline quartz crystals from ZnO/MgO/Al2O3/TiO2/ZrO2/SiO2 glasses

Glasses with the compositions 50.9 SiO₂ · 20.8 Al₂O₃ · (20.8 ? x) MgO· × ZnO · 3.7 TiO₂ · 3.7 ZrO₂ with x = 0, 2.3, 4.6 and 9.3 were annealed at temperatures in the range from 850 to 1100 °C. Depending on temperature, high- or low-quartz solid solutions, magnesium aluminosilicate, mullit and spinel precipitated. These glass–ceramics exhibit excellent mechanical properties and are potential candidates for applications in micromechanics or as hard disc substrate.The larger the ZnO concentration, the lower is the glass transition temperature. Also microhardnesses and Young’s moduli increased with increasing ZnO concentration. The nucleation temperature was of minor importance. To achieve good mechanical properties, the initially formed high-quartz phase must transform to the corresponding low-quartz phase. This occurs if the quartz phase contains only minor MgO or ZnO concentrations, which can be achieved by increasing the annealing times or temperature. Then MgO, ZnO and Al₂O₃ occur as separate spinel or gahnite phase.     

Synthesis and characterization of inorganic solid electrolytes of Li2O-SiO2-P2O5 and Li2O-TiO2-SiO2-P2O5 systems

The lithium-ion-conducting inorganic solid electrolytes in the oxide systems Li₂O-SiO₂-P₂O₅ and Li₂O-TiO₂-SiO₂-P₂O₅ were prepared by the solid-state reaction, and the electrolyte pellet made by cold-pressing method had diameter of 13 mm and was about 1 mm thick. Phase identification and surface morphology of the products were carried out by X-ray diffraction and scanning electron microscopy. Ionic conductivity of the pellets was investigated through ac impedance. The results show that the adding of other cations can improve the ionic conductivity of the solid electrolyte, and the sintering temperature and duration can influence the ionic conductivity. The maximum ionic conductivity in the samples is 9.9 × 10⁻⁴ S/cm in the Li₂O-TiO₂-SiO₂-P₂O₅ system. Original Russian Text ? W. Li, M. Wang, Z.H. Li, X.F. Shang, H. Wang, Y.W. Wang, Y.B. Xu, 2007, published in Elektrokhimiya, 2007, Vol. 43, No. 11, pp. 1341–1345.     

Cu-MOF催化过氧化氢应用于多巴胺的检测

本文利用一种具有H_2O_2催化活性的Cu-MOF[Cu_3(BTC)_2(H_2O)_3,简称HKUST-1],构建了以邻苯二胺(OPD)为颜色指示分子的比色传感体系,实现了对H_2O_2和多巴胺(DA)的快速灵敏检测。HKUST-1起到催化H_2O_2氧化OPD的作用,反应体系能够呈现出显著的颜色变化。在优化条件下,415nm处的吸收峰强度与H_2O_2浓度呈双线性关系,线性范围分别为10~50 mmol/L和50~100 mmol/L,相对标准偏差分别为0.9947和0.9995,最低检出限为1.29mmol/L。由于DA能抑制H_2O_2氧化OPD,因此比色传感体系还可以用于快速检测DA,线性范围分别为0.25~5μmol/L和2.5~25μmol/L,相对标准偏差分别为0.9783和0.9705,最低检出限为0.262μmol/L。该项工作拓展了Cu-MOFs材料在生物分子催化和生物传感方面的应用。