固体超强酸SO2-4/SnO2-TiO2-Al2O3催化合成PEG6000双山嵛酸酯

以自制的固体超强酸5O2-/SnO2-TiO2-Al2O3催化山嵛酸与聚乙二醇6000(PEG6000)的酯化反应,合成了PEG6000双山嵛酸酯(DB6000),其结构经IR确证.较适宜的反应条件为:PEG6000 80 mmol,n(山嵛酸)∶n(PEG6000) =2.2∶1.0,催化剂用量为总反应物质量的0.8％,氮气保护下于210℃反应6h,酯佗率高于99％.     

纳米固体超强酸SO2-4/Fe2O3催化合成尼泊金酸乙酯

以纳米固体超强酸SO2-4/Fe2O3催化尼泊金酸与乙醇的酯化反应合成了尼泊金酸乙酯.较适宜的反应条件为:尼泊金酸25 mmol,n(尼泊金酸):n(乙醇)=1:4,ω(催化剂)=3.73%,甲苯15 mL,于84℃～86℃反应3 h,产率达到93.3%.     

新工艺制备固体超强酸SO42-/SnO2-Nb2O5及其催化松油醇酯化

采用新工艺制备固体超强酸SO42-/SnO2-Nb2O5,将其应用于松油酯化反应。催化剂最佳制备条件:Nb2O5引入(SnO2质量分数)3%,浸渍硫酸浓度1.5 mol/L,500℃焙烧3.0 h;最佳反应条件:n(松油醇):n(乙酸酐)=1.0:1.2,催化剂用量(松油醇质量分数)5%,50℃反应3.0 h;并采用FT-IR、XRD、TG-DTA对催化剂进行表征。结果表明:催化剂可使得松油醇转化率达94.3%,乙酸松油酯选择性达86.2%,新工艺制备的催化剂较沉淀法和sol-gel法的活性高。     

固体酸ZrO2-Ce2O3/SO2-4催化合成丙二酸二丁酯

以含铈固体超强酸ZrO2-Ce2O3/SO4 2-为催化剂,丙二酸和正丁醇为原料合成了丙二酸二丁酯.最佳反应条件为:催化剂活化温度500℃,丙二酸100mmol,n(酸):n(醇)=1.0:2.5,催化剂用量1g,反应时间2h,酯化率达95.8%.结果表明,加入铈有助于提高固体超强酸的使用寿命.     

固体酸S2O82-/Nb2O5/La3+的制备、表征及催化合成乙酸正丁酯

以Nb₂O₅为载体,浸渍法研制固体酸（S₂O₈^2-/Nb₂O₅/La⁺）催化剂,经SEM、XRD和EDS表征,考察了固体酸的焙烧温度、陈化时间及S₂O₈^2-浓度等因素对该催化剂催化活性的影响。结果表明：在(NH₄)₂S₂O₈浓度为1 mol/L、浸渍时间18 h、w(La³⁺)=3%（基于Nb₂O₅的质量）、焙烧温度为500 ℃时,制备出最高催化效果的催化剂。接着考察了其催化合成乙酸正丁酯的催化活性,通过正交实验确定了反应的最佳条件：n(正丁醇)/n(冰醋酸）=2.0/1.0、催化剂用量w（S₂O₈^2-/Nb₂O₅/La³⁺）=2.9%（基于反应物质量）、反应温度为125 ℃,反应时间为3.0 h,酯化率为95.70%。催化剂循环利用3次后仍有90.1%的酯化率。      

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.     

ZnMn2O4纳米催化剂制备及催化合成乙酸正丁酯

本文以共沉淀法制备了四方晶系锌锰复合氧化物ZnMn2O4纳米催化剂。采用X射线粉末衍射(XRD)和透射电子显微镜(TEM)测试技术对样品进行了分析表征,结果表明所合成的催化剂为粒径均匀的纳米粒子,平均粒径在20-50 nm,具有较好的分散性。实验考察了所制备的ZnMn2O4纳米催化剂对乙酸和正丁醇酯化反应的催化活性,表明ZnMn2O4对乙酸正丁酯的合成有较高的催化活性;探讨了催化剂焙烧温度、催化剂用量、酸醇摩尔比以及反应时间对酯化率的影响,确定了适宜的酯化反应条件,以焙烧温度为300 ℃制备的ZnMn2O4为催化剂,在催化剂用量为0.3%(以反应物总质量计)、酸醇摩尔比n(酸):n(醇)=1.8:1、反应时间为4 h、酯化反应温度120 ℃的条件下,酯化率可达92.53%。     

固体超强酸ZrO_2/S2O_8~(2-)催化合成肉桂酸甲酯

研究了在固体超强酸ZrO2/S2O2-8催化下,肉桂酸与甲醇作用合成肉桂酸甲酯的工艺.考查了催化剂的用量、酸醇摩尔比、反应时间及催化剂的性能对反应的影响.最佳反应条件为∶n(肉桂酸)∶n(甲醇)=1∶10,m(肉桂酸)∶m(催化剂)=3∶1,反应温度90～95℃,反应时间5h,酯化率为95.7%.     

大孔SO42-/ZrO2-SiO2复合固体酸制备及催化性能

利用浸渍水解法在大孔SiO2载体上组装固体酸制备出大孔径SO42-/ZrO2-SiO2复合固体酸催化剂。用扫描电镜、红外光谱仪和粉末X射线衍射仪等对其进行表征,结果表明:大孔SiO2载体的毛细管效应促使ZrO2以纳米薄层方式均匀地沉积在SiO2薄层表面,并抑制了ZrO2晶体的生长和晶相的转变,载体的大孔全连通的结构赋予该复合材料高的通透性(孔径在1~2μm)、两面活性点和大的比表面积(约156 m2.g-1)。Hammett指示剂法测得经550℃焙烧后产物的酸强度H0值小于-13.75,属于固体超强酸。以乙酸正丁酯的合成为探针反应考察硫酸浸渍液浓度、焙烧温度等制备条件对其催化活性的影响,结果表明,该SO42-/ZrO2-SiO2固体酸具有较好的催化活性,当焙烧温度为550℃和硫酸浸渍液浓度为1.5 mol.L-1时,超强酸对酯化反应的催化酯化率达到97%。     

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。     

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.     

Solubility in the Na2Cr2O7-(NH4)2Cr2O7-K2Cr2O7-H2O system

Solubility in the Na₂Cr₂O₇-(NH₄)₂Cr₂O₇-K₂Cr₂O₇-H₂O four-component water-salt system at 25, 50, and 75°C was studied for the first time. Phase field boundaries for individual salts and potassium and ammonium dichromate solid solutions, monovariant lines, and invariant points were determined. Experimental data were used to optimize the looped isohydric process of potassium dichromate preparation involving additional salts.     

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…     

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.     

NaBO2-NaCl-Na2CO3, NaBO2- Na2CO3-NaMoO4, NaBO2- Na2CO3-NaWO4, and NaBO2-NaCl-Na2WO4 ternary systems

The phase diagrams of the NaBO₂-NaCl-Na₂CO₃, NaBO₂-Na₂CO₃-Na₂MoO₄, NaBO₂- Na₂CO₃-Na₂WO₄, and NaBO₂-NaCl-Na₂WO₄ ternary systems were studied by a calculation-experimental method and differential thermal analysis. The coordinates of ternary eutectics were determined: E ₁: 612°C, 16 mol % NaBO₂, 42 mol % NaCl, and 42 mol % Na₂CO₃; E ₂: 568°C, 12 mol % NaBO₂, 28 mol % Na₂CO₃, and 60 mol % Na₂MoO₄; E ₃: 575°C, 12 mol % NaBO₂, 32 mol % Na₂CO₃, and 56 mol % Na₂WO₄; E ₄: 628°C, 8 mol % NaBO₂, 20 mol % NaCl, and 72 mol % Na₂WO₄; and E ₅: 655°C, 9 mol % NaBO₂, 53 mol % NaCl, and 38 mol % Na₂WO₄.     

Li2SO4-Na2SO4-H2O和Li2SO4- K2SO4-H2O溶液的体积性质

本文用高精度数字式振荡管密度计测定了288K至318K温度范围内Li₂SO₄ + Na₂SO₄ + H₂O和 Li₂SO₄ + K₂SO₄ + H₂O三元体系的密度。混合溶液的离子强度范围从0.1到4.5 mol.kg_–1,混合溶液中Na₂SO₄和K₂SO₄的离子强度分数为0.2,0.4,0.6和0.8。用密度实验值拟合得到了不同温度下Pitzer离子相互作用模型混合参数θ_V和 ψ_V,模型的计算值与实验值的偏差在±0.002 g.cm_–3以内。用Pitzer模型计算了不同离子强度下三元体系的混合体积。     

(H2NC4H8NCH2CH2NH2)(HNCH2CH2NH2)3Zn2Ge2Se8: A new,templated one-dimensional ternary semiconductor stabilized by mixed organic cations

The novel, 1D semiconductor (H₂NC₄H₈NCH₂CH₂NH₂)(HNCH₂CH₂NH₂)₃Zn₂Ge₂Se₈ has been synthesized under solvothermal conditions using N-(2-aminoethyl)piperazine as solvent and templating agent at 200 °C. The material was characterized by single crystal and powder X-ray diffraction, IR and Raman spectroscopy and thermogravimetric analysis. The compound consists of 1D anionic [Zn₂Ge₂Se₈]⁴⁻ chains made of alternating edge-shared [ZnSe₄] and [GeSe₄] tetrahedra that charged balanced by one N-(2-aminoethyl)piperazinium and three piperazinium cations. The optical properties were investigated with solid state UV–Vis/near IR spectroscopy and the results show that the solid is a medium gap semiconductor with an absorption edge at 1.8 eV.     

Polymorphism in the Sc2Si2O7-Y2Si2O7 system

This paper examines the structural changes with temperature and composition in the Sc₂Si₂O₇-Y₂Si₂O₇ system; members of this system are expected to form in the intergranular region of Si₃N₄ and SiC structural ceramics when sintered with the aid of Y₂O₃ and Sc₂O₃ mixtures. A set of different compositions have been synthesized using the sol-gel method to obtain a xerogel, which has been calcined at temperatures between 1300 and 1750 °C during different times. The temperature-composition diagram of the system, obtained from powder XRD data, is dominated by the β-RE₂Si₂O₇ polymorph, with γ-RE₂Si₂O₇ and δ-RE₂Si₂O₇ showing very reduced stability fields. Isotherms at 1300 and 1600 °C have been analysed in detail to evaluate the solid solubility of the components. Although, the XRD data show a complete solid solubility of β-Sc₂Si₂O₇ in β-Y₂Si₂O₇ at 1300 °C, the ²⁹Si MAS-NMR spectra indicate a local structural change at x ca. 1.15 (Sc_2−xY_xSi₂O₇) related to the configuration of the Si tetrahedron, which does not affect the long-range order of the β-RE₂Si₂O₇ structure. Finally, it is interesting to note that, although Sc₂Si₂O₇ shows a unique stable polymorph (β), Sc³⁺ is able to replace Y³⁺ in γ-Y₂Si₂O₇ in the compositional range 1.86?x?2 (where x is Sc_2−xY_xSi₂O₇) as well as in δ-Y₂Si₂O₇ for compositions much closer to the pure Y₂Si₂O₇.     

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.     

Tl2S-Sb2S3-Bi2S3 quasi-ternary system

The Tl₂S-Sb₂S₃-Bi₂S₃ quasi-ternary system (system A) was studied using DTA, X- ray powder diffraction, microstructure examination, and microhardness measurements. TlSbS₂-Tl₄Bi₂S₅(TlBiS₂, Bi₂S₃), Sb₂S₃-TlBiS₂, Tl₃SbS₃-TlBiS₂(Bi₂S₃), and [TlSb_0.5Bi_0.5S₂]-Tl₂S isopleths; isothermal sections at 500 K; and liquidus surface projection of system A were constructed. Characteristic features of the title system are extensive fields of solid solutions extended along the TlSbS₂-TlBiS₂ quasi-binary section and a continuous solubility belt 1–2 mol % wide extended along the Sb₂S₃-Bi₂S₃ binary subsystem. Primary separation fields of phases and the types and coordinates of invariant and monovariant equilibria in system A were determined.