Pt／Al2O3催化剂GPLE烧结动力学的研究

在660℃空气气氛下对Pt／Al2O3催化剂进行了1006h的烧结实验。用氢氧滴定法测定了催化剂中铂的分散度,用环已烷脱氢表征了催化剂的活性。结果表明,经过500～600h的烧结后,铂的分散度和催化活性都达到了一个稳定状态。为GPLE烧结动力学提供了一组直接的证据。所得的分散度与活性数据都可用二级GPLE模型拟合,与Bartholomew的结论一致。     

VxTi复合氧化物催化剂用于二氧化碳气氛乙苯脱氢的研究

采用溶胶-凝胶法制备了以TiO₂为基体的VxTi复合氧化物催化剂，该催化剂用于乙苯二氧化碳低温氧化脱氢制苯乙烯反应。考察了活性组分含量和焙烧温度对催化剂活性的影响。结果表明，活性金属钒的添加有助于提高脱氢反应性能，但存在一适量值，摩尔分数超过5%，催化脱氢活性下降。通过XRD分析发现，不同焙烧温度制备的VxTi催化剂中TiO₂的晶相不同，随着温度的升高，TiO₂的晶相将由锐钛矿型转变为金红石晶相。TiO₂锐钛矿型晶相有利于苯乙烯选择性的提高，而金红石晶相则不利于催化剂的脱氢反应。     

合成条件对Pt负载γ-Al2O3催化剂在邻苯基苯酚合成中催化性能的影响

采用浸渍法制备了以γ-Al2O3为载体,Pt为活性组分的负载型催化剂,考察了不同制备条件对负载型贵金属催化剂在合成邻苯基苯酚中脱氢活性的影响.结果表明,浸渍液中活性组分的浓度、浸渍时间、有无竞争剂等对活性组分Pt在载体上的分散度有一定的影响,从而影响脱氢催化剂的活性.     

卤代烃对长链烷烃脱氢催化剂性能的影响

以C₁₈烷烃临氢脱氢反应为探针,考察原料中卤代烃对催化剂活性、稳定性和选择性的影响。结果表明,微量卤代烃的存在降低催化剂的脱氢反应活性,催化剂的稳定性也明显下降,副产物含量增多,选择性下降。原料中卤代烃质量分数应＜0.5%。     

溶胶-凝胶制备Pt／Al2O3的性质及在二聚物脱氢反应中的催化行为

本文采用溶胶-凝胶法制备Pt／Al2O3催化剂,考察了焙烧温度、还原温度对催化剂表面及结构性质的影响,并研究了该催化剂在二聚物脱氢反应中的脱氢活性,以及与浸渍法制备的催化剂进行了对比。对比结果显示,溶胶-凝胶法制备的催化剂热稳定性及活性组分抗烧结能力比浸渍法制备的催化剂高得多。     

化学文摘选译

金属催化剂的研究本文研究了无载体的Pt-Re催化剂和Pt-Re-AI_2O_3催化剂。用X射线研究了无载体催化剂的相。取得分散度数据。讨论了表面积。由CO的化学吸收作用研究此催化剂。由C_6H_6的氢化和环已烷的脱氢研究了催化活性。—译自美国《化学文摘》，1976，85，No．2，10696a     

长链烷烃（n-C10~13）脱氢制单烯烃催化剂的研究Ⅰ.氧化铝载体孔结构对催化剂性能的影响

通过n-C_10～13烷烃脱氢反应考察了氧化铝载体孔结构对长链烷烃脱氢催化剂性能的影响，结果表明，氧化铝载体的总孔容对催化剂影响不大，而有效孔容（孔径分布）影响催化剂的反应性能。小孔对载体的比表面积起主要作用，并影响催化剂的Pt分散度；大孔为催化剂金属位的积炭迁移提供有效空间。Pt与载体的强相互作用对提高催化剂的活性和稳定性有利。     

仲丁醇脱氢催化剂性能

采用XRD、TPR、BET和N2O滴定法对仲丁醇脱氢催化剂YTDH-1G与对比剂A进行表征,并采用常压固定床反应器考察两种催化剂的仲丁醇脱氢活性和甲乙酮选择性。结果表明,催化剂中添加Zr O2后可以提高催化剂活性组分的分散度,改善催化剂的还原性能。催化剂YTDH-1G表明的Cu比表面积和分散度明显大于对比剂A。在考察的实验范围,催化剂YTDH-1G的催化活性和产物选择性优于对比剂A,对工艺条件的适应性较强,可在较宽的温度和空速范围使用,具有较好的工业应用前景。     

TH-1型脱氢催化剂在CO2气提法尿素装置中的应用

中国石油大庆石化分公司大庆化肥厂尿素装置在2005年增产改造过程中，增设了CO₂脱氢系统，采用西北化工研究院的TH-1型脱氢催化剂，对使用该催化剂前、后的工业运行数据进行了分析，结果表明，脱氢系统投用后，高压系统尾气中H₂体积分数降低，催化剂活性没有明显下降，表明具有良好的低温活性和稳定性。工业应用结果表明，TH-1型脱氢催化剂起活温度比同类催化剂低，催化剂使用寿命延长，节能效果显著。     

铈及其前驱物对铁系乙苯脱氢催化剂性能的影响

考察了铈及其前驱物对乙苯脱氢制苯乙烯催化剂性能的影响,并采用程序升温还原（TPR）、X射线衍射（XRD）、扫描电子显微镜（SEM）、热重-差热分析（TG—DTA）和X射线能谱（EDAX）等技术对催化剂进行了表征。结果表明,不含铈的脱氢催化剂活性较低,苯乙烯收率为53．8％。添加铈后,可以较大幅度地提高乙苯脱氢反应中苯乙烯的收率。不同的铈源会影响到催化剂表面的形貌、铈的分布和催化剂的抗还原性,其中以硝酸铈作为前驱物所得的催化剂具有较高的活性和选择性。CeO2在脱氢反应条件下,部分被还原,可能与三价铁形成了新的活性中心,从而大幔度地提高了乙苯脱氢催化剂的活性。     

Catalytic behaviour of nickel and iron metal contaminants of an FCC catalyst after oxidative and reductive thermal treatments

The catalytic effects of nickel and iron deposited on an FCC (fluidized catalytic cracking) catalyst via metal naphthenates were studied in a micro activity test (MAT) unit after both oxidative and reductive treatments of the catalyst samples.The dehydrogenation activity of nickel was found to be close to the dehydrogenation activity of vanadium – and not several times higher than that of vanadium as is often reported – when deposited on the commercial FCC catalyst used in this study followed by steam deactivation (oxidative treatment) at 760 °C. However, the dehydrogenation activity of nickel was significantly intensified after post-treatment with a CO/N₂ mixture at this temperature (reductive treatment).The results show that iron did not have a dehydrogenation activity after steaming, but had a significant dehydrogenation activity after steaming when followed by exposure to the CO/N₂ mixture at 760 °C. The results indicate that the presence of deposited iron was inducing an additional catalytic cracking activity for the FCC catalyst.It was observed that co-impregnation of equal loadings of nickel, iron and vanadium on the FCC catalyst led to a considerably higher dehydrogenation activity than could be expected from the catalytic behaviour of the separate elements. The dehydrogenation activity was however slightly reduced by the reductive treatment as the reduced dehydrogenation activity from the lower oxidation state of vanadium (V³⁺) more than compensated the increased dehydrogenation activity of iron and nickel. A slightly increased gasoline production after the reductive treatment of the co-impregnated sample was a result of the increased production of gasoline from the FCC catalyst itself, which more than compensated for the reduced gasoline production from nickel.     

铁酸盐系列丁烯氧化脱氢催化剂研究进展

综述了铁酸盐系列催化剂(Fe系催化剂)在丁烯氧化脱氢反应中的应用研究进展,介绍了Fe系催化剂的活性中心和氧化脱氢机理,分析了催化剂的失活原因,详述了助剂对Fe系催化剂催化性能的影响,并对Fe系催化剂的发展方向进行了展望。开发出高反应活性、高选择性和高强度的新一代Fe系丁烯氧化脱氢制丁二烯的高效催化剂,是今后的主要研究方向,同时,开发资源利用率高、低投资、低生产成本和废水量少的丁烯氧化脱氢工艺也非常关键。     

醇类化合物制取醛类化合物过程综述

结合了醇类化合物制取醛类化合物的相关研究,将反应按照机理分为催化氧化和催化脱氢两种方式,对反应过程和工艺条件等作了详细归纳。分别介绍了常规反应体系条件下催化氧化法反应的催化剂和氧化剂,催化脱氢法所用的催化剂,对于转移脱氢等非常规反应以及醇氧化脱氢过程中的无溶剂作用时的反应也作了概括。通过工艺比较得到:一些传统类催化剂在通过一系列改性和负载化之后,其催化活性都能在醇的氧化脱氢制醛的过程中得到较好体现。随着研究的不断深入,环境友好型的催化剂的加大利用已逐渐成为一个趋势。然而更加高效和环保型催化剂的开发和使用,则需要研究者的进一步的努力。     

V–BaCO3 catalysts for the oxidative dehydrogenation of ethane

A new type of supported vanadium oxide catalyst V–BaCO₃, which consists of barium orthovanadate Ba₃(VO₄)₂ and BaCO₃ phases, has been used in the oxidative dehydrogenation of ethane. The catalyst with the ratio of V/Ba from 0.1 to 0.3 exhibited high catalytic activity for oxidative dehydrogenation of ethane, with particularly high activity for ethene production.     

The Oxidative Dehydrogenation of Propane Using Vanadium Oxide Supported on Nanocrystalline Ceria

Nanocrystalline ceria was prepared as a support for vanadium oxide catalysts and tested for the oxidative dehydrogenation of propane. Nanocrystalline ceria is very active for the total oxidation of propane under conditions used for oxidative dehydrogenation. The addition of vanadium results in a switch of activity to produce propene with appreciable selectivity. The catalyst performance depends on the vanadium loading. Lower vanadium loadings resulted in catalysts with highly dispersed vanadia species, which were selective towards propene production. Higher vanadium loadings resulted in the formation of a mixed cerium–vanadium phase, which was also active for propane selective oxidation. A catalyst with an intermediate loading was far less selective. Catalysts were characterised by a range of techniques (including XRD, laser Raman, TPR, SEM/EDX and XPS), and the activity of the catalysts can be related to their structure and chemistry.     

Effect of oxygen capacity and oxygen mobility of supported Mg3(VO4)2 catalysts on the performance in the oxidative dehydrogenation of n-butane

Vanadium-magnesium oxide (Mg₃(VO₄)₂) catalysts supported on Al₂O₃, ZrO₂, MgO, and CeO₂ were prepared by a wet impregnation method, and they were applied to the oxidative dehydrogenation of n-butane. Effect of oxygen capacity and oxygen mobility of supported Mg₃(VO₄)₂ catalysts on the catalytic performance in the oxidative dehydrogenation of n-butane was investigated. Experimental results revealed that large oxygen capacity of the catalyst was favorable for obtaining high catalytic activity at the initial stage of reaction, while facile oxygen mobility of the catalyst led to stable catalytic activity during the catalytic reaction in the oxidative dehydrogenation of n-butane.     

Oxidative dehydrogenation of propane over magnesium molybdate catalysts

Catalytic activities of magnesium molybdates were investigated for the oxidative dehydrogenation of propane with and without molecular oxygen under atmospheric pressure. Catalytic properties drastically changed with the catalyst composition, and it turned out that Mg_0.95MoO_x catalysts having slight excess molybdenum showed the highest activity in the oxidative dehydrogenation of propane, which gave 61% selectivity to propene at 22% conversion of propane at 515°C. The catalytic activities strongly depended on the acidic properties of the catalysts. It was also revealed that the lattice oxide ions of the catalysts participated as an active oxygen in the oxidative dehydrogenation of propane.     

铁酸锌纳米微粒的制备及其催化性能

采用溶胶 -凝胶法制备了铁酸锌纳米微粒催化剂 ,运用 DTA- TG、IR、XRD以及 BET比表面测试等手段对所制备的样品进行了表征。同时 ,考察了铁酸锌对二氧化碳选择性氧化乙苯制苯乙烯的催化性能。结果表明 :制备的铁酸锌为尖晶石型晶体 ,粒子的比表面积为 32 .5 m2 /g,晶粒大小约为 33nm。在由二氧化碳选择性氧化乙苯制苯乙烯的反应中表现出较好的催化活性     

Highly effective molybdena–manganese catalyst for propane oxidative dehydrogenation

A manganese oxide catalyst impregnated with molybdenum exhibits high yield, productivity and stability in the oxidative dehydrogenation of propane to propene. This catalyst exhibits catalytic activity and yield to propene at temperatures as low as 623 K. This revised version was published online in August 2006 with corrections to the Cover Date.     

N2O作为氧化脱氢剂的研究进展

综述了N2O作为氧化脱氢剂用于氧化还原体系的研究进展,介绍了N2O正丁烷氧化脱氢体系、丙烷氧化脱氢体系、N2O氧化苯制苯酚体系的研究结果,并重点总结了N2O氧化脱氢制苯乙烯的研究进展,讨论了N2O作为氧化脱氢剂的作用机制,认为今后应在催化剂改进、催化新材料的开发和N2O氧化脱氢反应机理等方面开展深入的研究,有效拓展N2O氧化脱氢剂的应用领域。