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1.
采用四种不同的方法制备了系列铁酸铁超微粒子催化剂,考察了其对乙苯和环己烷的氧化脱氢反应性能.结果表明,(D)样品具有最佳的乙苯氧化脱氢反应活性:400℃,O2/C6H5C2H5(mol)=3.0时,乙苯转化率为50%,苯乙烯选择性为80%,苯乙烯单收达40%.催化剂对乙苯氧化脱氢反应的活性随样品的粒径变小而提高,对环己烷氧化脱氢反应则恰好相反,即活性随粒径变小而降低.这种差别归因于反应物分子结构与催化剂表面原子配位结构的匹配作用.ESR结果对比表明,粒径小的粒子的原子配位结构对称性较低.  相似文献   

2.
合成5-氯2-氨基苯膦酸的新方法   总被引:1,自引:0,他引:1  
报道了以2.5-二氯苯胺为原料合成5-氯-2氨基苯膦酸的新方法,总产率达41%,是文献报道的以间氯苯胺为原料的合成方法的总产率的近3倍。  相似文献   

3.
Au/ZSM-5催化选择氧化环己烷制环己酮和环己醇的研究   总被引:9,自引:1,他引:9  
利用水热合成的方法制备了ZSM-5分子筛担载的纳米金催化剂.对合成的样品进行了XRD,XPS,Uv-Vis征分析,以环己烷催化氧化为探针反应.发现该催化剂对选择氧化环己烷制备环己酮和环己醇表现了优异的活性,环己烷的最高转化率可达到~16%.环己酮和环己醇的总选择性达到~92%.  相似文献   

4.
合成对异丙基苯胺分子筛催化剂的研究   总被引:2,自引:0,他引:2  
研究了分子筛催化剂上苯胺与异丙醇合成对异丙基苯胺的反应,得到了较佳的反应条件,反应温度623K~643K,空速1.0~1.3h^-1苯胺/异丙醇摩尔比1.0~2.0,HZSM-5分子筛经高温焙烧,水蒸气处理和氧化物改性后对异丙基苯胺选择性均有提高,经适当温度(1023K焙烧。723K水蒸气处理)处理其活性有一最佳值,以BET重量法测定了高温焙烧后HZSM-5环己烷的吸附等温表征其孔径大小,通过NH  相似文献   

5.
黄宇增  陈平 《分子催化》1996,10(4):289-293
V_2O_5/TiO_2体系引入Sb后催化剂的活性受到抑制,但苯甲醛选择性有所提高.在Sb/V=0.08(原子比),反应温度673K,氧浓度7%,空速14000h~(-1)时,甲苯转化率为22.8%,苯甲醛选择性69.7%,产率为15.9%.运用XRD、TPR、TPD考察了助剂锑对V_2O_5/TiO_2催化剂体系的体相结构,表面酸碱性及其还原性能的影响.结果表明,Sb的引入有利于V_2O_5的分散,催化剂表面酸中心数目减少,强度减弱,及V_2O_5还原温度提高,而表面高分散的V_O_5还原峰随Sb添加量增加出现极大值,反应过程也能够使V_2O_5更分散,有利于甲苯的选择氧化.  相似文献   

6.
在气流床快速热解装置上,系统地研究了内蒙东胜烟煤在氢气和氮气气氛中的快速热解行为。结果表明:在常压、700℃,煤在氢气氛中快速热解获得的液态烃的产率达2.6%,比在氮气氛中提高了80%,在6.0MPa的压力下,在氢气氛中的液态烃的产率是氮气氛的17倍;在常压、800℃时,在氢气氛中热解获得的甲烷产率达8.0%,比在同条件的氮气氛中提高了2.5倍,6.0MPa、700℃时,在氢气氛中的甲烷产率是氮气氛的5.3倍。烟煤在氢气氛中快速热解更有利于获取三苯(苯,甲苯,二甲苯)、三酚(苯酚,甲酚,二甲酚)和甲烷  相似文献   

7.
稀土复合氧化物催化合成丙交酯的研究   总被引:7,自引:0,他引:7  
以新型稀土La—Ti复合氧化物作为催化剂,催化乳酸合成丙交酯,考察了催化剂对反应体系粘度、丙交酯产率、反应时间、反应温度的影响,获得了较佳的反应工艺条件:减压下,70~90℃脱自由水1.5h;随后加入催化剂,用量为乳酸重量的0.8%,缓慢升温到120~140℃进行缩聚反应3~4h;再在170~260℃,保持升温速率为4℃/10min进行裂解,产物纯度和结构分别由Thiele管和红外光谱进行测定,丙交酯粗产率达88.5%,纯产率为40.2%,表明该催化剂具有良好的催化性能。  相似文献   

8.
烟煤快速加氢热解的研究:I.气氛影响的考察   总被引:4,自引:2,他引:4  
在气流床快速热解装置上,系统地研究了内蒙东胜烟煤在氢气和氮气气氛中的快速热解行为。结果表明:在常压、700℃,煤在氢气氛中快速热解获得的液态烃的产率达2.6%,比在氮气氛中提高了80%,在6.0MPa的压力下,在氢气氛中的液态烃的产率是氮气氛的17倍;在常压、800℃时,在氢气氛中热解获得的甲烷产率达8.0%,比在同条件的氮气氛中提高了2.5倍,6.0MPa、700℃时,在氢气氛中的甲烷产率是氮气  相似文献   

9.
四氯化锡催化合成氯乙酸异丙酯   总被引:18,自引:0,他引:18  
吴东辉  罗军  杨绪杰 《合成化学》2001,9(4):347-349
四氯化锡对由氯乙酸和异丙醇合成氯乙酸异丙酯的酯化反应具有较高的催化活性和选择性。当SnCI4量为2.0%(w)时,反应4h,氯乙酸异丙酯的产率为77.0%,纯度达97.9%。  相似文献   

10.
制备了一系列负载型V-Ti-Al-O催化剂并用于甲苯的气相选择性氧化制苯甲醛,考察了接触时间、氧浓度、V2O5负载量以及催化剂焙烧温度对反应性能的影响。用TPR、XRD和BET等测试手段,对催化剂进行了表征。研究发现,催化剂在773K时活化,接触时间1.2秒,氧浓度21%时,可获得较好的反应结果,V2O5负载量为6(wt)%的催化剂,在593K时反应,得到了转化率20.5%,苯甲醛产率8.3%的最好结果。  相似文献   

11.
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   

12.
13.
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   

14.
15.
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   

16.
TG and DTA studies on Me3SnO2PCl2, Me2Sn(O2PCl2)2 and Ph3SnO2PCl2 were carried out under dynamic argon atmosphere. The results show that the decomposition proceeds in different stages leading to the formation of Sn3(PO4)2 as a stable product. This compound was characterized by IR spectroscopy. Decomposition schemes involving reductive elimination reactions were proposed.  相似文献   

17.
18.
[(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   

19.
Wu YT  Linden A  Siegel JS 《Organic letters》2005,7(20):4353-4355
[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   

20.
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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