合成气制乙醇铑基催化剂研究进展

能源是现代社会赖以生存和发展的基础,乙醇作为一种优质的清洁能源,是很有应用前景的替代能源,它可由合成气催化转化制得。研发一种可以选择性生成乙醇并具有工业化应用前景的催化剂是该领域的研究热点。铑(Rh)基催化剂在合成乙醇、乙醛、乙酸的过程中因具有较好的乙醇选择性而备受关注。本文重点介绍了合成气催化转化制乙醇铑基催化剂的反应机理以及催化剂的活性中心、载体和助剂对催化活性、选择性的影响。     

铑基催化剂在合成气制乙醇中的研究进展

综述了铑基催化剂在合成气制乙醇中的研究进展,主要从铑基催化剂在合成气制乙醇中的生成机理、反应影响因素以及工业应用研究等方面进行介绍。铑基催化剂具有适中的CO吸附和解离能力,独特的乙醇等C_2含氧化合物的选择性,有望成为工业化应用的合成气制乙醇催化剂。     

铑基催化剂在合成气制乙醇中的研究进展

综述了铑基催化剂在合成气制乙醇中的研究进展,主要从铑基催化剂在合成气制乙醇中的生成机理、反应影响因素以及工业应用研究等方面进行介绍。铑基催化剂具有适中的CO吸附和解离能力,独特的乙醇等C_2含氧化合物的选择性,有望成为工业化应用的合成气制乙醇催化剂。     

铑基催化剂用于低碳醇合成反应研究进展

分别从反应机理、活性位点、助剂和载体4个方面对合成气制低碳醇铑基催化剂体系进行了文献综述,同时对理想催化剂的研究方向做出了预测.通过对不同学者的研究成果的对比,发现对于铑基催化剂催化的反应机理和活性中心等方面的研究仍存在较多争议,更为深入仔细的研究工作仍然需要.应用前景方面,虽然铑基催化剂对该反应具有较高的低碳醇选择性(尤其是乙醇)和较好的稳定性,但较低的反应活性及铑金属自身昂贵的价格很大程度上限制了其应用,具有工业应用价值的高效铑基催化剂仍有待开发.     

环己烷分子氧选择性氧化固体催化剂研究进展

对环己烷分子氧催化氧化制环己酮固体催化剂的最新进展进行了综述,重点介绍了贵金属催化剂、过渡金属及其氧化物催化剂和分子筛催化剂。指出锆基复合氧化物催化剂和负载在分子筛上的金催化剂具有较高的催化活性和选择性及好的稳定性,具有一定的应用及工业化前景。     

PEG20000催化技术研究及其工业化工艺开发

采用高活性复合钙基催化剂,在实验室及工业化压力反应器中合成了相对分子质量为20000的聚乙二醇,对催化剂种类、体系中水分含量和催化剂用量对聚合反应的影响进行了研究,并采用串联反应器分段聚合工业化放大工艺,充分结合PRESS循环喷雾反应器和釜式反应器的各自优势,实现了高黏度PEG20000的工业化生产。通过近红外、凝胶色谱和熔点等方法对合成的PEG20000进行表征,证实开发的复合钙基催化剂具有催化活性高、诱导时间短、产品相对分子质量控制精准、分子量分布窄等优点。     

PtBi气凝胶用于高效甲醇乙醇氧化电催化剂

高成本、低活性、低导电性电催化剂阻碍了直接醇类燃料电池的发展。金属气凝胶兼具气凝胶的高度多孔、大比表面积和金属的高导电、高催化活性于一身,在电催化领域展现出巨大的前景,极具研究价值。通过引入非贵金属Bi,发展了一类低成本、高活性的醇氧化合金气凝胶催化剂,为非贵金属基气凝胶催化剂的设计提供了启示。     

镍基催化剂调控的炔烃选择性加氢研究进展

炔烃选择性催化加氢反应对生产聚合级乙烯、苯乙烯和多种精细化学品具有重要意义。由于价格低廉和活性好等优点，近10年镍基催化剂在炔烃选择性催化加氢反应中展现出良好的应用前景。该文总结了国内外镍基催化剂调控的炔烃选择性加氢反应研究进展。结合反应历程和机理，指出了影响镍基催化剂催化活性、选择性和稳定性的主要因素。归纳了调控镍基催化剂性能的基本途径，包括单原子化、与金属/非金属合金化、有机配体修饰、构筑核壳和金属-载体相互作用结构。并讨论了炔烃选择性加氢中镍基催化剂存在的问题及解决策略。     

Ni与Co催化乙醇制氢研究进展

乙醇制氢具有环保、清洁、可持续等优点,其关键在于选择合适的催化剂。相较于贵金属催化剂而言,Ni与Co基催化剂因其具有成本低且活性高的优点,近年来在乙醇催化制氢中逐渐成为研究热点。然而Ni与Co基催化剂在催化乙醇水蒸气重整制氢的过程中仍存在着稳定性较差、低温催化活性低和使用寿命较短等问题。本文介绍了乙醇制氢的机理,围绕载体的类型及催化剂活性纳米颗粒的合金化改性,综述了近年来Ni与Co基催化剂催化乙醇水蒸气重整制氢的研究现状,总结了提高催化剂性能的方法及措施,并展望了Ni与Co基催化剂未来的发展方向,为颗粒尺寸小且低温催化活性高、稳定性好的Ni与Co基催化剂的制备提供思路。     

费托合成沉淀铁催化剂性能的研究进展

费托合成（F-F合成）是实现煤间接液化技术的重要环节之一,其关键是开发高活性、选择性和稳定性的催化剂。目前应用的费托合成催化剂主要有铁基和钴基催化剂。铁基催化剂因价格低廉、催化活性和水煤气变换反应（WGS）活性高以及助剂效果明显,而在费托合成催化剂中占有重要的地位。本文对近几年铁基催化剂的特点和发展状况进行了评述,着重分析了催化剂制备过程、助剂和还原活化对其活性和选择性的影响。     

Hydrogenation of Cinnamaldehyde over Pt‐Modified Molecular Sieve Catalysts

The catalytic properties of various Pt‐modified molecular sieves were tested in liquid‐phase hydrogenation of cinnamaldehyde and compared to Pt/MgO and commercial Pt/C catalysts. The type of support considerably influenced the catalytic properties. The superior selectivity performance of microporous catalysts was confirmed; the highest selectivity to allyl alcohol of about 40 % was obtained over the beta support whereas the mesoporous MCM‐41‐supported catalyst was unselective. The highest activity was obtained over the Pt/mordenite catalyst. In order to clarify the performance of catalysts, several characterization methods (XRD, XRF, FTIR, surface measurements) were employed.     

磺酸化碳材料负载Ru催化剂催化纤维素水解/加氢反应

采用纤维素衍生碳、活性炭和介孔碳材料CMK-3为不同碳源前驱体,在不同磺酸化条件下制备磺酸化碳材料负载Ru的双功能催化剂,并用FTIR光谱、XRD、元素分析、热重分析、N₂物理吸附 脱附进行了表征,考察了其对纤维素加氢反应的催化活性。结果表明：相比于纤维素衍生化碳,活性炭和介孔碳CMK-3为碳源经过磺酸化后制备的催化剂具有较强的结合-SO₃H的能力和较高的催化活性,对多元醇具有良好的选择性,170 ℃下反应10 h六元醇的收率可高达84.0%。在循环使用时,磺酸化活性炭负载Ru催化剂催化活性有所降低,但可以保持对多元醇的选择性;而磺酸化介孔碳负载Ru催化剂存在少量S流失,转化率基本不变,但产物的选择性有所降低。     

Fischer-Tropsch synthesis catalyzed by iron catalyst supported on porous polymers. II. Catalytic results

Macroporous styrene-divinylbenzene and 4-vinylpyridine-divinylbenzene copolymers were used as supports for an iron Fischer-Tropsch catalyst. The catalytic systems were studied in batch reactions of uniformly supported catalysts, continuous reactions of uniformly supported catalysts and continuous reactions of fully heterogenised catalysts. We have shown that the particular distribution of products and selectivity observed for the corresponding homogeneous catalytic systems are in general conserved in the supported ones. The supported induces a better selectivity in alkene synthesis, and for the fully heterogenised system there is, depending on the rate of gas flow, a relatively important selectivity in the oxy product.     

Styrene Epoxidation over Carbon Nanotube-Supported Gold Catalysts

Carbon nanotube supported gold catalysts prepared by deposition–precipitation with urea (DP urea) were characterized by various techniques. Its catalytic activity was examined for the oxidation of styrene using t-butylhydroperoxide as oxidant. This system showed good epoxide selectivity. The other factors, such as solvent, reaction time, concentrations of oxidant and catalyst, have also been investigated and reaction conditions are optimized. It is a novel highly active/selective and reusable heterogeneous catalyst for styrene epoxidation.     

铂催化硅氢加成反应研究进展

硅氢加成反应是合成有机硅材料最重要的途径之一，铂催化剂作为其应用最广的催化剂，具有重要的意义。本文首先介绍了硅氢加成反应机理的研究现状；分析了聚合物长链段铂配合物、含多个铂原子铂簇化合物及N-杂环卡宾铂配合物均相铂催化剂的研究进展，致力于改善均相催化剂催化选择性差、催化活性难以控制等缺点；分别阐述了不同铂催化剂载体如无机二氧化硅、炭载体、金属氧化物、有机高分子、固载液等作为铂催化剂载体的优点，负载铂催化剂具有可回收、产物选择性好的优点，有效解决了工业上铂损失的问题；最后对铂催化硅氢加成反应的发展趋势进行了展望分析，铂负载能力的提高、铂负载催化剂的分离、硅氢加成反应的原理、催化范围的扩大等均是今后研究的重要方向。     

MWW型分子筛的高效清洁合成及其在苯与乙烯烷基化反应中催化性能

研究了MWW型分子筛合成过程中模板剂六亚甲基亚胺加入量对产物晶相、结晶度、形貌、孔结构和酸性等物化性能的影响。结果表明,通过加入晶种,利用晶种的导向作用,能有效提高MWW型分子筛的晶化速率,大幅降低配料中有毒模板剂六亚甲基亚胺用量,达到分子筛高效清洁生产的目的。在制得的MWW型分子筛中加入黏结剂制成催化剂,工业装置操作条件下评价其在苯与乙烯液相烷基化反应中的活性、选择性、产物分布及稳定性等,并进行了2 000 h寿命试验,结果表明,乙烯转化率接近100%,乙基化选择性大于99.7%,催化剂性能稳定,满足工业应用要求。     

Structured but not over-structured: Woven active carbon fibre matt catalyst

Catalytic hydrogenation of citral was studied on a Pt on active carbon cloth (ACC) catalyst, with a Pd in ionic liquid on ACC and a commercial Pt on active carbon powder catalysts. The metal was supported on active carbon either by direct impregnation or utilizing the ionic liquid as the intermediate phase on the carbon. The influence on selectivity and activity, of the most important variables, such as temperature and pressure, was investigated in a batch reactor. Four consecutive experiments were carried out with each catalyst. The aim with the reuse of catalysts in the batch reactor was to elucidate eventual catalyst deactivation. The decrease in activity was very notable in the case of traditional impregnated catalysts, whereas the novel SSIL-TM (structured supported ionic liquid-transition metal) or Pd in ionic liquid on active carbon essentially maintained its activity in four consecutive batches. The catalysts were characterized with scanning electron microscopy, N₂ physisorption, and inductively coupled plasma analysis combined with mass spectroscopy. With the Pt on active carbon fibre catalyst, 80–100% selectivity of carbonyl group hydrogenation was achieved at 15% conversion, whereas the Pd in ionic liquid on ACC catalyst displayed an impressive metal efficiency (citral-to-Pd ratio of 156, mol:mol), selectivity (45%) and activity (92% conversion at 140 min) as well as tolerance towards catalyst deactivation. Supported ionic liquids provide a new reaction environment for catalytic transformations.     

Activity and characterization of Pd thin films,microfabricated dots,and cluster based model catalysts

The use of various model catalysts' configurations is illustrated to study the relation between catalytic activity and surface structure. The hydrogenation of 1,3‐butadiene is used as a test reaction to correlate kinetic parameters with catalysts' properties. The first model catalysts studied were Pd thin films. STM and XPS were used to characterize the catalyst and correlate the effect of sulfur poisoning with catalytic activity. It was found that the kinetic parameters depended on both the sulfur content and surface morphology. It is speculated that morphological changes caused by sulfur reconstruction change the distribution of active sites. The second model catalyst was a microfabricated catalyst consisting of a regular array of catalytic dots. Dots with different compositions were prepared to study the effect of Pd–Au alloys on activity. It was found that addition of gold decreased the activation energy and reduced the number of active sites by diluting the surface. The third type of model catalysts studied are catalysts derived from molecular clusters of clusters which have a well defined structure and composition. Upon pyrolysis, these materials decompose and form self‐supported porous bimetallic catalysts. It was found that the activity and selectivity of these materials varied with the structure of the precursor as well as with the temperature used to decompose them. These type of model catalysts provide a novel route to design new catalysts. This revised version was published online in June 2006 with corrections to the Cover Date.     

糠醛选择性催化加氢的研究进展

糠醛是种可再生的生物质能源,可从农副产品中萃取得到。糠醛加氢可合成很多高附加值的产物,如糠醇、四氢糠醇、2-甲基呋喃、呋喃、2-甲基四氢呋喃、环戊酮、环戊醇和1,4丁二醇等。糠醛氢化反应除了碳碳双键、呋喃环氢化外,还有其他衍生副反应(脱羰、开环反应、缩合反应、C O键氢化等)。糠醛催化加氢催化剂主要为金属催化剂以及非晶态合金催化剂,单金属催化剂用于反应时的选择性和活性较低,通常采用添加助剂或是另一种金属以提高催化剂的活性和选择性,目前糠醛选择性催化加氢的研究主要集中在催化剂载体和双金属催化剂的研制上。主要阐述糠醛选择性催化加氢催化剂研究进展,指出在研制低成本、高选择性、稳定性、绿色环保的催化剂同时,催化剂的工业化应用研究有待进一步完善,最终以实现糠醛高效高选择性加氢工业应用为目的。     

纳米二氧化硅负载磷钨酸催化合成2-十二烷基苯

采用纳米二氧化硅为载体,负载磷钨酸制备催化剂,催化合成制备2-十二烷基苯。实验表明:纳米二氧化硅负载磷钨酸制备的催化剂在烷基化反应中表现出很好的催化性能;优化的工艺条件为m(苯)∶m(1-十二烯)=8∶1,反应时间为2h,反应温度为80℃,催化剂负载量和加入量分别为20%(m/m)和2%(m/m,以反应物总量计);催化剂对苯与1-十二烯合成反应表现出较高活性和选择性。通过对反应产物进行高效液相色谱质谱联用仪分析,结果显示产物直链性较好。