SO4^2-/TiO2催化合成乙酸戊酯

以Ti（OBu）4为原料，采用溶胶-凝胶法制备了固体超强酸SO4^2-/TiO2，其结构经XRD，DRS及IR表征。以SO4^2-/TiO2为催化剂，通过乙酸与戊醇反应合成了乙酸戊酯。讨论了影响酯化率的主要因素。实验结果表明，当催化剂用量为0．6g，乙酸87．3mmol，醇酸摩尔比为1．4：1．0，于115℃反应6h时，平行实验的平均酯化率可达94．2％。     

SO_4~(2-)/TiO_2催化合成乙酸戊酯

以Ti(OBu)4为原料,采用溶胶-凝胶法制备了固体超强酸SO24-/TiO2,其结构经XRD,DRS及IR表征。以SO24-/TiO2为催化剂,通过乙酸与戊醇反应合成了乙酸戊酯。讨论了影响酯化率的主要因素。实验结果表明,当催化剂用量为0.6 g,乙酸87.3 mmol,醇酸摩尔比为1.4∶1.0,于115℃反应6 h时,平行实验的平均酯化率可达94.2%。     

焙烧温度对纳米级SO2- 4/TiO2固体超强酸性能的影响

用锐钛型纳米TiO2制备了纳米级SO2- 4/TiO2固体超强酸,考查了焙烧温度对酸强度、比表面积、红外光谱及其催化活性的影响.结果显示该催化剂在450℃焙烧3 h,可以形成纳米级SO2-4/TiO2固体超强酸的结构.用该催化剂催化乙酸和丁醇酯化反应可使酯化率达到98.4%.     

焙烧温度对纳米级SO_4~(2-)/TiO_2固体超强酸性能的影响

用锐钛型纳米TiO2制备了纳米级SO42-/TiO2固体超强酸,考查了焙烧温度对酸强度、比表面积、红外光谱及其催化活性的影响.结果显示该催化剂在450℃焙烧3 h,可以形成纳米级SO42-/TiO2固体超强酸的结构.用该催化剂催化乙酸和丁醇酯化反应可使酯化率达到98.4%.     

稀土固体超强酸SO2-4/TiO2/Ce(Ⅳ)催化合成乙酸正丁酯

以SO2-4/TiO2/Ce(Ⅳ)为催化剂,乙酸和正丁醇为原料合成了乙酸正丁酯,在n(醇)∶n(酸)=1.4,催化剂0.5g(乙酸200mmol时),反应时间1.5h的优化反应条件下,酯化率在96%以上.     

焙烧温度对纳米级SO4^2-／TiO2固体超强酸性能的影响

用锐钛型纳米TiO2制备了纳米级SO4^2-／TiO2固体超强酸，考查了焙烧温度对酸强度、比表面积、红外光谱及其催化活性的影响．结果显示该催化剂在450℃焙烧3h，可以形成纳米级SO4^2-／TiO2固体超强酸的结构，用该催化剂催化乙酸和丁醇酯化反应可使酯化率达到98．4％。     

稀土固体超强酸SO_4~(2-)/TiO_2/Ce(Ⅳ)催化合成乙酸正丁酯

以SO2 -4/TiO2 /Ce(Ⅳ )为催化剂 ,乙酸和正丁醇为原料合成了乙酸正丁酯 ,在n(醇 )∶n(酸 ) =1.4 ,催化剂0 .5g(乙酸 2 0 0mmol时 ) ,反应时间 1.5h的优化反应条件下 ,酯化率在 96 %以上。     

SO_4~(2-)/TiO_2固体超强酸新制备方法及其对形成邻苯二甲酸二丁酯的催化活性

建立了用钛白粉制备固体超强酸SO42-/TiO2的新方法.考察了超强酸SO42-/TiO2的制备条件对催化邻苯二甲酸酐和正丁醇酯化反应的催化活性的影响.实验表明,以合成的超强酸为催化剂,在160℃反应4h,邻苯二甲酸二丁酯的产率大于99%.     

稀土固体超强酸SO4^2—／TiO2／Ce（Ⅳ）催化合成乙酸正丁酯

以SO4^2-/TiO2/Ce(Ⅳ)为催化剂，乙酸和正丁醇为原料合成了乙酸正丁酯，在n(醇)：n(酸)＝1．4，催化剂0．5g(乙酸200mmol时)，反应时间1．5h的优化反应条件下，酯化率在96％以上。     

稀土固体超强酸SO2-4/TiO2/La3 +催化合成丙酸苄酯

采用浸渍法制备了稀土固体超强酸SO2-4/TiO2/La3+,并运用IR、XRD和Hammett指示剂法对其进行了表征.以制备的固体超强酸SO2-4/TiO23+为催化剂、丙酸和苯甲醇为原料合成了丙酸苄酯.考察了催化剂的制备条件及合成条件对酯化率的影响,结果显示催化剂最佳制备条件:钛前体氧化物的浸渍液为含0.07 mol·L-1 La3+的硫酸溶液,焙烧时间3 h,焙烧温度500℃.最佳反应条件:醇酸摩尔比为1:2、催化剂用量为苯甲醇用量的9.3%、反应时间3 h、反应温度120℃,酯化率达84.0%以上.用IR、1H-NMR等手段对产品进行了表征.     

Sc2MgGa2 and Y2MgGa2

Scandium magnesium gallide, Sc₂MgGa₂, and yttrium magnesium gallide, Y₂MgGa₂, were synthesized from the corresponding elements by heating under an argon atmosphere in an induction furnace. These intermetallic compounds crystallize in the tetragonal Mo₂FeB₂‐type structure. All three crystallographically unique atoms occupy special positions and the site symmetries of (Sc/Y, Ga) and Mg are m2m and 4/m, respectively. The coordinations around Sc/Y, Mg and Ga are pentagonal (Sc/Y), tetragonal (Mg) and triangular (Ga) prisms, with four (Mg) or three (Ga) additional capping atoms leading to the coordination numbers [10], [8+4] and [6+3], respectively. The crystal structure of Sc₂MgGa₂ was determined from single‐crystal diffraction intensities and the isostructural Y₂MgGa₂ was identified from powder diffraction data.     

Electrochemical study of (NEt4)2Cl2FeS2MoS2 and (NEt4)2Cl2FeS2MoS2FeCl2

Summary The ability of [MoS₄]^2–, anions to be used as ligands for transition metal ions has been widely demonstrated, especially with Fe²⁺. The present study has been restricted to linear complexes such as (NEt₄)₂ [Cl₂FeS₂MoS₂] and (NEt₄)₂[Cl₂FeS₂MoS₂FeCl₂]. Their electrochemical properties are described: upon electrochemical reduction, these compounds yield MoS₂, as a black precipitate, and an iron complex in solution, assumed to be [SFeCl₂]^2–. The electrochemical reduction goes through two electron transfers, coupled with the breakdown of the molecular skeleton: a DISPl and an ECE mechanism. Depending on the solvent, the following equilibrium may be observed: [Cl₄Fe₂MoS₄]^2–[Cl₂FeMoS₄]^2–+FeCl₂. The equilibrium constant, K_D, was evaluated by differential pulse polarography. K_D is tightly related to the donor number of the solvent.     

The alkali hypophosphites KH2PO2, RbH2PO2 and CsH2PO2

The structures of the hypophosphites KH₂PO₂ (potassium hypophosphite), RbH₂PO₂ (rubidium hypophosphite) and CsH₂PO₂ (caesium hypophosphite) have been determined by single‐crystal X‐ray diffraction. The structures consist of layers of alkali cations and hypophosphite anions, with the latter bridging four cations within the same layer. The Rb and Cs hypophosphites are isomorphous.     

Zur Kenntnis der Dialkalimetalldichalkogenide β-Na2S2, K2S2, α-Rb2S2, β-Rb2S2, K2Se2, Rb2Se2, α-K2Te2, β-K2Te2 und Rb2Te2

On Dialkali Metal Dichalcogenides β-Na₂S₂, K₂S₂, α-Rb₂S₂, β-Rb₂S₂, K₂Se₂, Rb₂Se₂, α-K₂Te₂, β-K₂Te₂ and Rb₂Te₂ The first presentation of pure samples of α- and β-Rb₂S₂, α- and β-K₂Te₂, and Rb₂Te₂ is described. Using single crystals of K₂S₂ and K₂Se₂, received by ammonothermal synthesis, the structure of the Na₂O₂ type and by using single crystals of β-Na₂S₂ and β-K₂Te₂ the Li₂O₂ type structure will be refined. By combined investigations with temperature-dependent Guinier-, neutron diffraction-, thermal analysis, and Raman-spectroscopy the nature of the monotropic phase transition from the Na₂O₂ type to the Li₂O₂ type will be explained by means of the examples α-/β-Na₂S₂ and α-/β-K₂Te₂. A further case of dimorphic condition as well as the monotropic phase transition of α- and β-Rb₂S₂ is presented. The existing areas of the structure fields of the dialkali metal dichalcogenides are limited by the model of the polar covalence.     

Formal [(2+2)+2] and [(2+2)+(2+2)] nonconjugated dienediyne cascade cycloadditions

[reaction: see text] Fluoranthene 2 and heptacycle 3 are easily accessible from the reaction of diyne 1 and norbornadiene (NBD) in the presence of the rhodium catalyst. The unusual [(2+2)+(2+2)] adduct 3 was confirmed by the X-ray crystal structure analysis.     

Crystal Structures of [Bu2Sn(O2PPh2)2], [Ph2Sn(O2PPh2)2], and [PhClSn(O2PPh2)OMe]2. Raman Spectra of [Ph2Sn(O2PPh2)2] and [PhClSn(O2PPh2)OMe]2

[(n‐Bu)₂Sn(O₂PPh₂)₂] ( 1 ), and [Ph₂Sn(O₂PPh₂)₂] ( 2 ) have been synthesized by the reactions of R₂SnCl₂ (R=n‐Bu, Ph) with HO₂PPh₂ in Methanol. From the reaction of Ph₂SnCl₂ with diphenylphosphinic acid a third product [PhClSn(O₂PPh₂)OMe]₂ ( 3 ) could be isolated. X‐ray diffraction studies show 1 to crystallize in the monoclinic space group P2₁/c with a = 1303.7(1) pm, b = 2286.9(2) pm, c = 1063.1(1) pm, β = 94.383(6)°, and Z = 4. 2 crystallizes triclinic in the space group , the cell parameters being a = 1293.2(2) pm, b = 1478.5(4) pm, c = 1507.2(3) pm, α = 98.86(3)°, β = 109.63(2)°, γ = 114.88(2)°, and Z = 2. Both compounds form arrays of eight‐membered rings (SnOPO)₂ linked at the tin atoms to form chains of infinite length. The dimer 3 consists of a like ring, in which the tin atoms are bridged by methoxo groups. It crystallizes triclinic in space group with a = 946.4(1) pm, b = 963.7(1) pm, c = 1174.2(1) pm, α = 82.495(6)°, β = 66.451(6)°, γ = 74.922(6)°, and Z = 1 for the dimer. The Raman spectra of 2 and 3 are given and discussed.     

Die Photoionenspektren von SCl2, S2Cl2 und S2Br2

Photoionization Mass Spectra of SCl₂, S₂Cl₂, and S₂Br₂ Photoionization mass spectra of SCl₂, S₂Cl₂, and S₂Br₂ have been measured. Heats of formation, bond energies, and ionization potentials of fragments have been calculated from appearance potentials.