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1.
丁烷氧化制顺丁烯二酸酐催化剂活性相的研究 总被引:4,自引:0,他引:4
通过活性测试及催化剂表征研究了用于丁烷氧化制顺酐VPO催化剂的反应控制步骤-脱氢反应的机理,分析了(VO)2P2O7(020)面的催化脱氢过程,同时对β—VOPO4相在催化脱氢过程中的作用进行了研究。丁烷氧化制顺酐VPO催化剂中,最重要的活性相是(VO)2P2O7,而(020)面是(VO)2R2O7的活性面。与此同时,β—VOPO4相也是重要的活性相,只有在β—VOPO4相与(VO)2R2O7协同作用下,方可对丁烷分子进行较适当地活化,使脱氢作为控制步骤能够顺利进行。 相似文献
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Polymer‐bound 2,2′‐bipyridine cobalt complexes PSBPY‐Co, PSBPY‐Co‐bipy, PSBPY‐Co‐oxine, and PSBPY‐Co‐phen (where PSBPY: polystyrene bound‐2,2′‐bipyridine; bipy: 2,2′‐bipyridine; phen: 1,10‐phenanthroline) were synthesized and investigated by IR, X‐ray photoelectric spectroscopy, thermogravimetry–differential thermal analysis, inductively coupled plasma atomic emission spectrometry, and elemental analysis. The complexes were found to be catalysts for the oxidation of alkylbenzenes and cyclohexene in the presence of molecular oxygen in the absence of solvent. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 1068–1074, 2000 相似文献
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研究了谷氨酸水杨醛希夫碱配合物(Sal—Glu—M)对环己烯的催化氧化性能,详细探讨了谷氨酸水杨醛希夫碱钴配合物(Sal—Glu—Co)在不同反应条件下对环己烯的催化氧化性能,找到了谷氨酸水杨醛希夫碱钴配合物对环己烯较好的催化氧化反应条件。 相似文献
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晶格氧用于轻烃的选择氧化 总被引:2,自引:0,他引:2
In this paper, selective oxidation of n-butane to maleic anhydride (MA) and partial oxidation of methane to synthesis gas with lattice oxygen instead of molecular oxygen are investigated. For the oxidation of butane to MA in the absence of molecular oxygen, the Ce-Fe promoted VPO catalyst has more available lattice oxygen and provides higher conversion and selectivity than that of the unpromoted one. It is supposed that the introduction of Ce-Fe complex oxides improves redox performance of VPO catalyst and increases the activity of lattice oxygen.For partial oxidation of methane to synthesis gas over LaFeO3 and Lao.8Sro.gFeO3 oxides, the reaction with flow switched between 11% O2-Ar and 11% CH4-He at 900℃ was carried out. The results show that methane can be oxidized to CO and H2 with selectivity over 93% by the lattice oxygen of the catalyst in an appropriate reaction condition, while the lost lattice oxygen can be supplemented by air re-oxidation. It is viable for the lattice oxygen of the LaFeO3 and La0.8Sr0.2FeO3 catalyst instead of molecular oxygen to react with methane to synthesis gas in the redox mode. 相似文献
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鸡西褐煤碱氧氧化的研究 总被引:2,自引:0,他引:2
选用鸡西褐煤 ,在 1 80~ 2 4 0℃下 ,于氢氧化钠和水溶液中用氧气氧化 ,考察了碱煤比、反应温度、氧初压、反应时间及水量对芳香羧酸产率的影响。实验结果表明 ,碱煤比和氧初压是影响芳香羧酸产率的主要因素 相似文献
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醇类的分子氧催化氧化反应研究进展 总被引:2,自引:0,他引:2
目前,国外广泛地使用分子氧(或空气)催化氧化醇类以合成羰基化合物。分子氧是化工生产中很受欢迎的一种“绿色”氧化剂而且便宜易得。此处介绍的是目前国外已发现的多种这类反应的以铂系金属为主的催化剂。它们大多数具有高的催化转化率和很好的选择性。 相似文献
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研究了高分子担载水杨醛谷氨酸希夫碱配合物(PS-Sal-Glu-M)催化氧化环己烯的性能,详细探讨了反应温度、反应时间、催化剂用量、反应添加剂对高分子担载水杨醛谷氨酸希夫碱铜配合物催化氧化环已烯的反应性能的影响。研究表明,在常压下,用分子氧作作为氧化剂,不需要溶剂及共还原剂,环己烯可以被氧化生成环己烯醇和环已烯酮,产物的分离提纯比较容易,催化剂可以循环使用。 相似文献
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Several phases reported as minor or major phases in the active MoVTeNbO catalysts have been prepared and investigated for the oxidation of propane into acrylic acid. Activity and selectivity of pure phases and mixtures of phases obtained either directly from synthesis or by co-grinding have been compared. The results obtained confirmed that the orthorhombic M1 phase is the most active and selective phase and is responsible for the major part of the efficiency of the best catalysts. However, they also clearly demonstrated that a synergism due to a cooperation between phases occurs, similar to that previously proposed between the M1 [(Te2O)M20O56] and M2 [(TeO)M3O9] phases for the ammoxidation of propane. The origin of this phase cooperation is discussed. 相似文献
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This mini review summaries recent works on identifying the active surfaces for CO oxidation on Pd, Pt, and Rh under oxygen rich conditions. A significantly high reaction rate for CO oxidation under oxygen rich conditions has been observed. Results using in situ characterization methods of ambient scanning tunneling microscope, surface X-ray diffraction, ambient pressure X-ray photoemission spectroscopy, X-ray absorption spectroscopy, and infrared reflection adsorption spectroscopy (IRAS), were included. Most X-ray related methods reveal that the achievements of the high reaction rates for CO oxidation on Pd, Pt, and Rh under oxygen rich conditions are accompanied with the appearance of oxides on the surface, leading to that the oxide phase is considered to be the active surface. In contrast, recent in situ IRAS results conclude that a chemisorbed oxygen covered metallic surface is the active surface. Kinetic data support that the reaction on the metallic surfaces can reach the high rate, e.g. a mass-transfer limit turnover frequency, without the necessity of the presence of oxide. Therefore, we point out that the appearance of oxides on Pt-group metals during CO oxidation is possibly due to the transfer-limit of CO gas, resulting in exposing the catalyst surface to an ambient atmosphere much richer in oxygen and thus building-up the oxide. Moreover, photons in X-ray related experiments may aid to overcome the formation barrier of oxide on a chemisorbed oxygen covered metallic surface. The formation of oxide is also affected by the mass-transfer properties of the in situ reaction cells. If the amount of incoming CO molecules under the mass-transfer limit of CO is high enough, the build-up of oxide may be precluded being consumed by reacting with CO. 相似文献
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Jelka Diedenhoven Dr.‐Ing. Andreas Reitzmann Dr. Gerhard Mestl Prof. Dr.‐Ing. Thomas Turek 《化学,工程师,技术》2012,84(4):517-523
A model for the phosphorus dynamics in vanadium‐phosphorus oxide (VPO) catalysts for the oxidation of n‐butane to maleic anhydride was developed. According to the model, reversible sorption processes determine the phosphorus content of the catalyst. Simulations reveal that several phenomena can be successfully described. If no phosphorus is added to the reactant feed, the catalytic activity increases until runaway occurs. With addition of a proper amount of phosphorus, the loss can be compensated while excessive phosphorus addition results in complete catalyst deactivation. Adjusting the model parameters to experimental data may result in a model that can be used to optimize the performance of maleic anhydride reactors. 相似文献
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Study of Mn-based Catalysts for Oxidative Dehydrogenation
of Cyclohexane to Cyclohexene 总被引:2,自引:0,他引:2
The gas-phase oxidative dehydrogenation (ODH) of cyclohexane to cyclohexene in the presence of molecular oxygen has been studied
over various Mn-based catalysts. It is found that LiCl/MnOx/PC (Portland cement) catalyst exhibits the highest catalytic performance, and a 42.8% cyclohexane conversion, 58.8% cyclohexene
selectivity and 25.2% cyclohexene yield can be achieved under 600 °C, 20,000 h−1 and C6H12/O2/N2=14/7/79. There are good correlations between the selectivities to cyclohexene and the electrical conductivities of Li doped
Mn-based catalysts, from which it is deduced that the non-fully reduced oxygen species (O2−, O22−, O−) involved in a new phase of LiMn2O4 might be responsible for the high selectivity toward cyclohexene, whereas the Mn2O3 crystal phase results in the COx formation. The selectivity to cyclohexene increases with increasing molar ratio of Li to Mn in LiCl/MnOx/PC. 相似文献
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针对分子氧氧化环己烯制备环己烯酮的催化反应体系,以Co(Ⅱ)为活性中心,3,5-二氯水杨醛与邻苯二胺为配体,胺化的MCM-41型介孔分子筛为载体,用化学键联法制备出一种固载型希夫碱催化剂。进而考察了该催化剂对分子氧氧化环己烯制备环己烯酮的工艺条件,结果表明,在常压、催化剂用量0.15 g(2 mL环己烯)、乙腈20 mL、氧气流量5 mL/min、反应温度60℃、反应时间8 h、叔丁基过氧化氢(TBHP)0.04 mL的条件下,环己烯酮的单程收率达54.87%,催化剂容易分离回收,可重复使用。 相似文献
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本文在丁烷/空气气氛下,系统地考察了活化过程对正丁烷氧化制顺酐钒磷氧系催化剂性能的影响.活化前后的催化剂用XRD、IR、SEM、EPMA、TEM和比表面进行了较全面地表征,并与催化剂的活性进行了关联.结果表明:活化过程对催化剂相转变、比表面积、表面磷钒比(P/V)等有明显的影响.活化前后催化剂的形貌基本不变.实验证明(VO)_2P_2O_7是正丁烷选择性生成顺酐的活性相.催化剂活性防活化时间的增加而增长,并趋于稳定,但活性诱导期随之缩短.通过研究找到了工业催化剂的适宜活化条件,在该条件下活化的催化剂具有活性高、选择性好、活性诱导期短的特点. 相似文献
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采用杂多离子复合相转移催化剂,环己烯为原料、低含量过氧化氢为氧源合成了环氧环己烷,筛选了相转移催化剂,探讨了催化活性物种的生成原理及环氧化反应的作用机制.实验结果表明,双十六烷基二甲基氯化铵和双十八烷基二甲基氯化铵与磷钨杂多离子复配表现出较好的环氧化反应活性;较优的反应条件为:n(Q3[PW4])∶n(C6H10)∶n(H2O2)=1∶200∶130,反应温度50~60 ℃,pH=4.5~5.5,时间1~4 h;环己烯转化率40%~50%,过氧化氢利用率80%~90%,环氧环己烷的收率为80%~86%(扣除回收的环己烯).与传统的环氧化工艺相比,工艺简单、污染少、收率高,工业化可行性强. 相似文献