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固体超强酸因其特殊的晶相结构和表面特性及高比表面积使其具有许多重要的催化特性[1],某些经特殊处理得到的金属氧化物(如ZrO2、TiO2、Fe 2O3等)负载SO24-后可以成为固体超强酸[2]..有关SO24-/ZrO2系列固体超强酸的研究和应用报道较多[3,4a,5].夏勇德等[4b,6]报道用(NH4)2S2O8浸渍无定形Zr(OH)4可制备超强酸性和催化活性比SO24-/ZrO2更强的新型固体超强酸S2O28-/ZrO2.本文在文献方法的基础上,制出新型固体超强酸S2O28-/ZrO2-Al2O3,以乙酸和正丁醇的酯化反应作探针,优选出高活性催化剂并成功地用于催化合成4种缩酮(醛)类化合物.它们经纯化处理后均可作为食用香料. 相似文献
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以马来酸酐和异戊醇为原料,复合型固体超强酸ZrO2-TiO2/SO2-4-为催化剂催化合成了马来酸二异戊酯.最佳工艺条件为:催化剂活化温度450℃,活化时间5 h,1.0 mol·L-1H2SO4,催化剂用量1.0 g,酸醇摩尔比为1:4,回流分水70 min,酯化率达98.72%.ZrO2-TiO2/SO2-4-具有良好的催化活性,可重复使用5次以上. 相似文献
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SO2-4/TiO2-SiO2固体超强酸的结构及其光催化性能 总被引:10,自引:0,他引:10
自从Arata等[1]首次报道无卤素型SO2-4/MxOy固体超强酸体系以来, 对该类催化剂的研究引起了人们的广泛重视. 大量研究工作表明, 固体超强酸催化剂对丁烷异构化、苯衍生物烷基化、链烷烃裂解和乙烯二聚等诸多酸催化的反应表现出极高的反应活性[2]. 最近, 我们把SO2-4/TiO2型固体超强酸应用于有机物的光催化氧化反应, 研究发现TiO2光催化剂经H2SO4浸渍处理形成固体超强酸后, 催化剂的光催化活性大大提高, 并具有很好的反应活性、稳定性和抗湿性能[3]; 相似文献
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催化精馏专用填料型固体酸SO42-/ZrO2-Al2O3-Al的研究 总被引:2,自引:0,他引:2
为了研制催化精馏专用催化剂,采用铝阳极氧化法制备了Al2O3-Al一体型载体,并将活性固体超强酸SO42-/ZrO2引入到Al2O3-Al上,得到一种新型催化精馏专用填料式固体酸SO42-/ZrO2-Al2O3-Al催化剂.利用XRD、 SEM、 BET、 XPS、 NH3-TPD等手段对其进行了表征.结果表明,所制得的阳极氧化铝膜厚为56 μm, SO42-/ZrO2-Al2O3-Al固体酸具有比表面积大、酸强度适中的特点.XRD结果表明, ZrO2在Al2O3-Al上处于高度分散状态.将该固体酸用于乙酸/乙醇酯化反应中,显示出较高的催化活性,且稳定性较好. 相似文献
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固体酸ZrO2-Ce2O3/SO2-4催化合成丙二酸二丁酯 总被引:2,自引:0,他引:2
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. 相似文献
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Martin Sahlberg Yvonne Andersson 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(3):i7-i8
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. 相似文献
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Paul-Louis Fabre Dominique de Montauzon René Poilblanc 《Transition Metal Chemistry》1987,12(5):434-440
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, KD, was evaluated by differential pulse polarography. KD is tightly related to the donor number of the solvent. 相似文献
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Marina I. Naumova Natalia V. Kuratieva Nina V. Podberezskaya Dmitry Yu. Naumov 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(5):i53-i55
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. 相似文献
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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. 相似文献
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[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. 相似文献
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[(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. 相似文献
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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. 相似文献