铁/活性炭催化剂上费-托合成反应产物分布的非Anderson-Schulz-Flory特性

 在浆态反应釜中研究了铁／活性炭催化剂上费－托合成（Fischer－Tropschsynthesis,FTS）反应产物分布和链增长几率（Anderson－Schulz－Flory（ASF）链增长几率和本征链增长几率）．产物分布通常在C1处和C2处偏离ASF分布,呈现C1处偏高而C2处偏低的情况．本征链增长几率的研究结果表明,以活性炭为载体的铁基费－托合成催化剂上存在烯烃的再吸附二次反应,使产物分布偏离ASF分布．铁／活性炭催化剂上同时伴随水煤气变换（watergasshift,WGS）反应．XRD检测到铁／活性炭催化剂上存在FexC和Fe3O4两种物相．     

浆态床F-T合成Fe/Cu/K/SiO2催化剂中K助剂作用的研究

采用低温N2吸附、H2 TPR、CO2 TPD、MES、XRD,考察了K的加入顺序对两组微球状费托(F-T)合成Fe/Cu/K/SiO2催化剂的织构性质、还原行为、碳化行为、物相变化以及反应性能的影响。结果表明,K的加入顺序对催化剂的织构性质影响很小。先加Si后加K的催化剂具有较强的表面碱性,抑制催化剂在H2气氛下的初始还原,但促进了催化剂的碳化,且在浆态床F T反应中表现出良好的反应稳定性,较高的FTS反应活性,较低的甲烷选择性以及较高的重质烃和烯烃选择性,表现出良好的工业应用前景。     

费托合成 Fe基催化剂中铁物相与活性的关系

 采用连续共沉淀和喷雾干燥相结合的方法制备了微球形 Fe 基催化剂, 采用 N2 吸附-脱附、X 射线衍射和穆斯堡尔谱等手段, 考察了催化剂在不同还原条件下铁物相的转变, 并在浆态床反应器中评价了催化剂的费-托合成 (FTS) 反应性能. 结果表明, Fe 基催化剂在合成气气氛下首先从α-Fe2O3 转变为 Fe3O4, 然后转变为铁碳化物 (FexC); 还原压力的增大有利于 α-Fe2O3 向 Fe3O4 的转变, 而抑制 Fe3O4 向 FexC 的转变; 还原空速的增加则促进 Fe3O4 转变为 FexC. 催化剂的 FTS 反应活性随着催化剂中 Fe3O4 含量的增加而逐渐下降, 而随着 FexC 含量的增加而逐渐上升.     

浆态床FT合成中铁催化剂的穆斯堡尔谱

浆态床ＦＴ合成中铁催化剂的穆斯堡尔谱赵玉龙，李哲（中国科学院山西煤炭化学研究所煤转化国家重点实验室，太原）（中国科学院地质研究所，北京）关键词穆斯堡尔谱，铁催化剂，浆态床ＦＴ合成ＦＴ合成铁系催化剂的穆斯堡尔谱的研究工作已经发表很多，但是浆态操作条件下...     

费托合成鼓泡浆态床反应器模型化研究

建立了费托合成鼓泡浆态床反应器双泡模型,通过模型对比的方法模拟讨论了多个反应器模型,双泡模型、全混模型以及多级串联模型,对比模拟讨论了费托合成反应各模型的适用性。模拟结果说明,全混模型适用于费托合成动力学行为的考察模拟;多级串联模型在一定的级数下能够近似模拟鼓泡浆态床中费托合成反应结果,更适用于探讨返混对费托合成反应行为的影响;双泡模型能够描述鼓泡浆态床中流体力学对反应的影响。     

还原温度与时间对铁基催化剂浆态床F-T合成性能的影响

在浆态床反应器中考察了未还原催化剂以及在240℃和270℃的还原温度下还原时间对Fe/Cu/K/SiO2催化剂F-T合成反应性能的影响，采用Mssbauer谱研究了还原和反应后催化剂的物相组成。结果表明，在240℃延长还原时间或将还原温度升高到270℃均有利于催化剂的还原，270℃还原的催化剂的活性和稳定性明显高于未还原和240℃还原的催化剂，催化剂的运行稳定性与催化剂在反应过程中的流失量有密切关系。催化剂高温还原时烃产物分布倾向于生成低碳数的烃类，在相同的还原温度下，烃产物选择性随还原时间的延长向轻组分方向偏移。     

用于浆态床FT合成的Fe-Cu-K-Si催化剂的初步考察

使用连续共沉淀反应器制备了浆态床FT合成用的Fe-Cu-K-Si催化剂。考察了钾含量、粘合剂的添加以及催化剂还原方法等对催化剂性能的影响。1L高压搅拌釜的试验结果表明粘合剂添加方法B和低压CO还原条件下的No.9催化剂性能较好。在质量空速为无载体Fe-Cu-K催化剂1.5倍的条件下，No.9催化剂的合成气转化率，C1^ 和C5^ 产物的产率均高于无载体Fe-Cu-K催化剂，甲烷选择性为3．2％。特别在富CO合成气条件下C5^ 的单程产率达到130g/m^3(CO H2)以上。假设对氢为一级反应动力学的条件下，使用表观速率常数对o.9催化剂的反应活性的经时变化作了考察，结果表明表观速率常数较合成气转化率能相对地反映不同反应条件下的催化剂活性。     

浆态床合成二甲醚复合催化剂失活原因探索

在反应温度260℃、压力5.0MPa的条件下,对浆态床反应器中二甲醚合成复合催化剂的失活规律进行了研究。结果表明, Cu基催化剂失活较快是导致浆态床二甲醚合成催化剂不稳定的主要原因。通过分析Cu基催化剂在浆态床反应器和固定床反应器中的活性变化规律,发现在浆态床反应器中不能及时导出反应体系的H2O对催化剂的毒副作用导致了浆态床Cu基催化剂快速失活。对失活催化剂进行的TPR、XRD和SEM EDS表征结果可以看出,Cu粒子的长大和积炭是Cu基催化剂失活的重要原因,与已有文献报道不同的是并未发现明显的Cu元素流失。     

浆态床合成二甲醚复合催化剂失活原因探索

在反应温度260 ℃、压力5.0 MPa的条件下,对浆态床反应器中二甲醚合成复合催化剂的失活规律进行了研究.结果表明,Cu基催化剂失活较快是导致浆态床二甲醚合成催化剂不稳定的主要原因.通过分析Cu基催化剂在浆态床反应器和固定床反应器中的活性变化规律,发现在浆态床反应器中不能及时导出反应体系的H2O对催化剂的毒副作用导致了浆态床Cu基催化剂快速失活.对失活催化剂进行的TPR、XRD和SEM-EDS表征结果可以看出,Cu粒子的长大和积炭是Cu基催化剂失活的重要原因,与已有文献报道不同的是并未发现明显的Cu元素流失.     

高分散费-托合成铁/活性炭催化剂的研究 Ⅳ.催化剂特性

使用原位穆斯堡尔谱和微型反应器考察了铁/活性炭催化剂在不同物相时的F-T反应性以及在实际反应中的物相及其变化,并讨论了铁/活性炭系催化剂不同于传统F-T铁催化剂的特性。发现金属态铁比还原到Fe_3O_4时具有高得多的活性和对烯烃和高碳烃的选择性。在实际反应中,金属铁可转化为碳化铁(ε’-Fe_(2·2)C、ε-Fe_2C和x-Fe_5C_2)并受担载铁粒径的制约,但这些碳化铁与F-T反应性间似没有确定的相依关系。影响F-T反应性的主要是铁在载体上的分散度以及铁质,即活性炭与载体的相互作用。铁与活性炭间合适的相互作用既使铁有较高的还原度,又可能调变铁的电子性不仅是载体,还可能起着电子给予体的作用,促进碳链的增长。而活性炭丰富的微孔又限制了过长链烃的生成。这些特点使得铁/活性炭催化剂具备活性高、气态烯烃和高碳烃(C_5~+)选择性高以及烃分布相对集中的优点。     

Intermolecular forces for D2, N2, O2, F2 and CO2

The intermolecular potentials for D₂, N₂, O₂, F₂ and CO₂ are determined on the basis of the second virial coeffincients, the polarizabilities parallel and perpendicular to the molecular axes, and the electric quadrupole moment. The repulsive parts of the potentials are taken from the corresponding Kihara core-potentials. Effects of the octopolar induction are taken into consideration in a unique way. The potential depends on relative orientations of the two molecules as well as the distance r between the molecular centers. This dependence is shown in graphs. A measure of the anisotropy of the potential depth is 0.72 for CO₂ 0.36 for D₂, and smaller than 0.27 for N₂ O₂ and F₂. The remarkable anisotropy for CO₂ and D₂ is due to strong electrostatic quadrupole interactions.     

配合物[Cu(H2O)(C12H8N2)2].2ClO4的合成、性质及晶体结构

合成了配合物[Cu(H2O)(C12H8N2)2]*2ClO4(C12H8N2为1,10-邻菲咯啉),用元素分析、摩尔电导、红外光谱及电子光谱进行了表征,并测定了配合物的晶体结构.该晶体属单斜晶系,空间群为CC;晶胞参数a=1.9177(2)nm,b=0.81994(0)nm,c=1.62458(14)nm,β=100.104(6)°;V=2.5419(4)nm3,Z=4,F(000)=1300,DC=1.693g/cm3,R=0.0430,wR=0.1195.中心铜(Ⅱ)离子与两个1,10-邻菲咯啉的四个N原子和一个水分子的氧原子配位,形成了一个变形的三角双锥结构.     

Ba3 (VO4)2-K2 Ba(MoO4)2 and Pb3 (VO4)2-K2 Pb(MoO4)2 systems

Phase equilibria in the Ba₃(VO₄)₂-K₂Ba(MoO₄)₂ and Pb3(VO₄)₂-K₂Pb(MoO₄)₂ systems have been investigated. In the first system, a continuous series of substitutional solid solutions with the palmierite structure is formed, and in the second one, the polymorphic transition in lead orthovanadate at 100°C restricts the extent of the palmierite-type solid solution to 10–100 mol % K₂Pb(MoO₄)₂. Original Russian Text ? V.D. Zhuravlev, Yu.A. Velikodnyi, A.S. Vinogradova-Zhabrova, A.P. Tyutyunnik, V.G. Zubkov, 2008, published in Zhurnal Neorganicheskoi Khimii, 2008, Vol. 53, No. 10, pp. 1746–1748.     

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.     

Phase transitions in Ca3(BN2)2 and Sr3(BN2)2

α-Ca₃(BN₂)₂ crystallizes in the cubic system (space group: ) with one type of calcium ions disordered over of equivalent (8c) positions. An ordered low-temperature phase (β-Ca₃(BN₂)₂) was prepared and found to crystallize in the orthorhombic system (space group: Cmca) with lattice parameters: , , and . Structure refinements on the basis of X-ray powder data have revealed that orthorhombic β-Ca₃(BN₂)₂ corresponds to an ordered super-structure of cubic α-Ca₃(BN₂)₂. The space group Cmca assigned for β-Ca₃(BN₂)₂ is derived from by a group-subgroup relationship.DSC measurements and temperature-dependent in situ X-ray powder diffraction studies showed reversible phase transitions between β- and α-Ca₃(BN₂)₂ with transition temperatures between 215 and 240 °C.The structure Sr₃(BN₂)₂ was reported isotypic with α-Ca₃(BN₂)₂ () with one type of strontium ions being disordered over of equivalent (2c) positions. In addition, a primitive () structure has been reported for Sr₃(BN₂)₂. Phase stability studies on Sr₃(BN₂)₂ revealed a phase transition between a primitive and a body-centred lattice around 820 °C. The experiments showed that both previously published structures are correct and can be assigned as α-Sr₃(BN₂)₂ (, high-temperature phase), and β-Sr₃(BN₂)₂ (, low-temperature phase).A comparison of Ca₃(BN₂)₂ and Sr₃(BN₂)₂ phases reveals that the different types of cation disordering present in both of the cubic α-phases () have a directing influence on the formation of two distinct (orthorhombic and cubic) low-temperature phases.     

Zur Trennung von H2, O2, N2, NO, CO, N2O, CO2, C2H6, C2H4, C2H2, NO2(N2O4) und Feuchtigkeit

Ohne Zusammenfassung     

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.     

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.     

Synthesis and structural investigation of the compounds containing HF2 anions: Ca(HF2)2, Ba4F4(HF2)(PF6)3 and Pb2F2(HF2)(PF6)

Three new compounds Ca(HF₂)₂, Ba₄F₄(HF₂)(PF₆)₃ and Pb₂F₂(HF₂)(PF₆) were obtained in the system metal(II) fluoride and anhydrous HF (aHF) acidified with excessive PF₅. The obtained polymeric solids are slightly soluble in aHF and they crystallize out of their aHF solutions. Ca(HF₂)₂ was prepared by simply dissolving CaF₂ in a neutral aHF. It represents the second known compound with homoleptic HF environment of the central atom besides Ba(H₃F₄)₂. The compounds Ba₄F₄(HF₂)(PF₆)₃ and Pb₂F₂(HF₂)(PF₆) represent two additional examples of the formation of a polymeric zigzag ladder or ribbon composed of metal cation and fluoride anion (MF⁺)_n besides PbF(AsF₆), the first isolated compound with such zigzag ladder. The obtained new compounds were characterized by X-ray single crystal diffraction method and partly by Raman spectroscopy. Ba₄F₄(HF₂)(PF₆)₃ crystallizes in a triclinic space group P1¯ with a=4.5870(2) Å, b=8.8327(3) Å, c=11.2489(3) Å, α=67.758(9)°, β=84.722(12), γ=78.283(12)°, V=413.00(3) Å³ at 200 K, Z=1 and R=0.0588. Pb₂F₂(HF₂)(PF₆) at 200 K: space group P1¯, a=4.5722(19) Å, b=4.763(2) Å, c=8.818(4) Å, α=86.967(10)°, β=76.774(10)°, γ=83.230(12)°, V=185.55(14) ų, Z=1 and R=0.0937. Pb₂F₂(HF₂)(PF₆) at 293 K: space group P1¯, a=4.586(2) Å, b=4.781(3) Å, c=8.831(5) Å, α=87.106(13)°, β=76.830(13)°, γ=83.531(11)°, V=187.27(18) Å³, Z=1 and R=0.072. Ca(HF₂)₂ crystallizes in an orthorhombic Fddd space group with a=5.5709(6) Å, b=10.1111(9) Å, c=10.5945(10) Å, V=596.77(10) Å³ at 200 K, Z=8 and R=0.028.     

Vapour-liquid equilibrium data for the systems C2H6 + N2, C2H4 + N2, C3H8 + N2, and C3H6 + N2

High pressure vapour-liquid equilibrium data for the C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂ systems are presented. The data are obtained isothermally in the range from 200 K to 290 K. For each point of data, temperature, pressure and liquid and vapour phase mole fractions are measured.Values for the vapour phase mole fractions are calculated from the obtained pressure, temperature and liquid phase mole fractions. The calculated values are compared with the experimental results, and it is found that the average mean deviation between calculated and experimental mole fractions is less than 0.009 for the systems considered in this work.