保留取代基团的苯环选择加氢反应催化剂研究进展

具有复杂取代基团苯基衍生物的苯环选择加氢属于原子经济反应,不仅可以消除苯环对人体健康的潜在危害,而且能够赋予所合成材料以特殊功能。该文综述了保留取代基团苯环选择加氢反应的催化剂、操作条件及反应性能的研究进展,主要包括芳香二胺、芳香酯类、芳香族氨基甲酸甲酯、聚苯乙烯、联苯及双酚A等的苯环催化加氢反应。为了使苯环上取代基团不发生反应,多采用Rh、Ru、Pd和Pt等贵金属催化剂。Ni等非贵金属催化剂的活性和选择性有待进一步提高。因此,今后研究重点应是开发减量或替代贵金属的高性能催化剂。     

多相贵金属催化剂对芳香化合物催化加氢研究进展

综述了近年来多相贵金属催化剂对芳香化合物加氢的研究；揭示了负载型铂、钯、钌、铑以及二元金属催化剂各自在加氢反应中的特点，以及载体、助催化剂对其活性和选择性的重要作用；同时介绍了TCSM和Raney型贵金属催化剂的概况。     

大连化物所纳米金催化研究获进展

正近日,中国科学院大连化学物理研究所研究员张涛、刘晓艳团队在金催化研究方面取得新进展,采用锌铝水滑石负载的硫醇保护Au25原子团簇作为前驱体制得的纳米金催化剂,在含有其它不饱和取代基团的芳香硝基化合物选择加氢反应中表现出较高的选择性。芳胺是合成各种医药、农药、染料、聚合物及精细化学品的重要中间体,其主要通过芳香硝基     

Pd/C催化剂催化邻硝基苯胺加氢制备邻苯二胺

卤代芳胺是重要的有机中间体,广泛应用于合成染料、农药、医药、香料及橡胶助剂等。卤代芳香硝基化合物通过液相催化加氢制备卤代芳胺的技术以其环境友好、产品质量稳定和工艺先进而受到重视。用负载型贵金属催化剂催化芳香硝基化合物选择加氢制备相应的芳胺有广泛的应用价值。采用邻硝基苯胺为原料,Pd/C为催化剂,低压催化加氢还原合成邻苯二胺,考察不同溶剂、反应压力、反应温度和反应时间对产物收率的影响。结果表明,在甲醇为溶剂、反应温度100 ℃、反应压力0.8 MPa和反应时间100 min条件下,邻苯二胺平均收率为97%。与传统硫化碱还原或铁粉化学法还原工艺相比,以甲醇为溶剂,Pd/C催化剂催化加氢法在减少废水和降低成本等方面有较大优势。     

催化加氢制备4,4′-ODA研究进展

综述了催化加氢制备4,4′-二氨基二苯醚(4,4′-ODA)的研究进展，重点介绍了加氢催化剂、催化工艺和溶剂的选择。负载型镍(Ni)基催化剂、包覆Ni纳米颗粒催化剂和非晶态Ni-B合金催化剂均表现出优异的加氢活性和选择性，有望取代传统的贵金属加氢催化剂。混合溶剂比单一溶剂更理想，可以提高产品的收率和纯度。未来的发展重点是开发催化加氢连续化生产工艺及相应的催化剂，以降低生产成本，提高产品质量。     

含氧芳香族苯环化合物的加氢催化剂研究进展

综述了含氧芳香族苯环化合物加氢反应中催化剂的研究现状，重点介绍了Pd、Pt、Ru和Rh基加氢催化剂的研究及应用。指出了不同含氧芳香族化合物所用的适宜催化剂。Pd和Pt催化剂适用于酚及苯基醚类化合物的加氢反应，Ru和Rh则适用于作为芳香族羧酸的加氢催化剂。     

二硝基甲苯加氢制甲苯二胺催化剂的研究进展

综述了二硝基甲苯液相加氢合成甲苯二胺催化剂的研究进展,并介绍了(Pd+Pt)/C等贵金属催化剂、雷尼镍催化剂、负载型镍基催化剂、非晶态镍催化剂和漆原镍催化剂的最新研究成果。通过对比上述各催化剂在生产成本、制备工艺及催化二硝基甲苯加氢性能等方面的优缺点,发现非晶态镍催化剂不但价格低廉,而且在1 MPa低压二硝基甲苯液相加氢的反应中表现出与(Pd+Pt)/C工业催化剂相似的活性和选择性,是替代二硝基甲苯液相加氢贵金属和雷尼镍工业催化剂的首要选择;漆原镍催化剂制备工艺简单,价格低廉,且在众多的加氢反应中表现出与骨架镍催化剂相似的催化性能,也具有较大的工业化潜质。     

大连化物所单原子催化研究取得进展

正近日,中国科学院大连化学物理研究所张涛院士团队与美国亚利桑那州立大学刘景月教授(该所"千人计划")一起合作,在单原子催化研究领域取得新进展。首次将Pt/Fe Ox单原子及准单原子催化剂用于含有不饱和取代基团的芳香硝基化合物的选择加氢反应,在温和反应条件下(40℃,氢气压力0.3 MPa)获得了极高的活性和选择性。以3-硝基苯乙烯选择加氢为例,其TOF值达到1500 h-1,比文献中报道的最优催化剂的活性高20倍;氨基苯乙烯选择性接近99%,是目前所报道的Pt基催化剂中的最高值,而且催化剂可磁性分离、具有良好的循环稳定性和底物普适性。单原子和准单原子优异的催化性能可归结于催化剂中孤立的带正电的Pt活性位,这些活性位有利于硝基的优先吸附并同时抑制C=C的加氢。该工作于近期发表于     

分子筛负载铂催化剂上四氢萘加氢裂解反应行为

四氢萘是多环芳烃加氢转化的产物或者中间体,其加氢裂解行为和规律的研究在重芳烃转化和脱除领域有着重要的意义。采用等体积浸渍法制备得到了氧化铝负载贵金属(Pt,Ir和Pd)催化剂和酸性分子筛(MOR和ZSM-5)负载铂双功能催化剂,考察了它们催化四氢萘加氢裂解的反应行为。氧化铝为载体时金属催化剂表面主要发生加氢及脱氢反应,其中金属Pt表现出最高的加氢和脱氢活性。双功能催化剂上四氢萘发生加氢裂化、异构化、氢转移及烷基化等复杂反应,金属Pt通过氢溢流作用提高了分子筛Br?nsted酸活性从而提高催化剂加氢裂解活性和选择性,但过量金属Pt会加剧苯环加氢而不利于单环芳烃的生成。分子筛孔道的限域作用对四氢萘的反应活性及产物分布有重要影响,相比Pt/ZSM-5催化剂,Pt/MOR表现出更高的裂解活性及异构化选择性。Pt/MOR催化剂上四氢萘加氢裂解主要通过异构-裂解路径进行,异构化活性及异构体构型决定了裂解活性及产物的分布。     

除炔烃用贵金属加氢催化剂

一种活性高的选择性贵金属加氢催化剂现正投入工厂实际使用,过去使用的选择性加氢催化剂是活性较低的选择性加氢硫化金属催化剂。新催化剂具有很大的经济性,操作温度低,乙烯损失少。表明,贵金属催化剂能够直接取代目前大多数工厂通用的硫化金属催化剂。前加氢催化剂。美国绝大多数工厂采用前加氢方法。使用硫化非贵金属催化剂。在原料气中加进少量     

Catalysts with noble metals based on super-cross-linked polystyrene for the hydrogenation of aromatic hydrocarbons

A series of catalysts containing noble metals on a super-cross-linked polystyrene (SCP) support with a developed specific surface area (>1000 m²/g) and high thermal stability are prepared and studied to develop an effective catalyst for the low-temperature hydrogenation of aromatic hydrocarbons. A study of Pt- and Pd-containing catalysts based on SCP, carbon supports, and alumina in the hydrogenation of simple (benzene, toluene), branched (n-butylbenzene) and polycyclic (terphenyl) aromatic compounds is conducted. In the hydrogenation of aromatic hydrocarbons, the activity of the catalysts on SCP is comparable to or surpasses analogous catalysts based on Al₂O₃ and Sibunit in the content of noble metals; it is established that catalysts on SCP have greater selectivity in the hydrogenation of benzene in a benzene-toluene mixture. The electronic state of metals in the Pt(Pd)/SCP catalysts is studied by the IR spectroscopy of adsorbed CO. In testing the catalysts in the hydrogenation of terphenyl, it is found that Pt-containing catalyst on the SCP can operate in reversible hydrogenation-dehydrogenation cycles (terphenyl-tercyclohexane); this is promising for the use of such catalyst systems in creating composite materials for hydrogen storage.     

Hydrogenation of aromatic aldehydes to aromatic hydrocarbons over Cu-HZSM-5 catalyst

With benzaldehyde as a model compound, the hydrogenation of aromatic aldehydes to aromatic hydrocarbons was investigated. Cu-HZSM-5 exhibited excellent catalytic performance for the reaction. The obtained catalysts were characterized by N₂ adsorption/desorption, N₂O chemisorptions, X-ray diffraction, NH₃-temperature programmed desorption and X-ray photoelectron spectroscopy. It was found that Cu⁰ active species exhibited poor activity for the hydrogenation of benzene ring, while the strong acidity of HZSM-5 accelerated the hydrogenation reaction via hydrogen spillover phenomenon and the C–O activation effect. In addition, the catalyst was proved to be effective for the hydrogenation of a series of aromatic aldehydes to corresponding aromatic hydrocarbons.     

Evaluation of different reaction strategies for the improvement of cetane number in diesel fuels

Cetane number improvement of diesel fuels is a difficult task that refiners will face in the near future. Aromatics saturation by deep hydrogenation is a necessary, but perhaps not sufficient step in the diesel treatment. Some researchers have proposed selective ring opening (SRO) as an additional step in the upgrading. In this work, we explore some possible reaction pathways of compounds typically found in diesel after different levels of hydrogenation, i.e. decalin (decahydronaphthalene), perhydrophenanthrene, tetralin (1,2,3,4-tetrahydronapthalene), as well as 1-ring and 2-ring aromatic phenanthrenes. We have estimated the cetane number (CN) of each individual compound involved in the reaction pathways, using an artificial neural network program that was trained with pure compound cetane numbers from a database. The results demonstrate the great challenge that reaching high CN represents. In the conversion of decalin, acidic catalysts alone are not able to yield products with CN significantly higher than the decalin feed. Similarly, no significant gain in CN can be expected with hydrogenolysis metal catalysts operating via the dicarbene mechanism. Only in the case of selective metal-catalyzed hydrogenolysis, with preferential cleavage at substituted C–C bonds, the predicted products have CN substantially higher than the decalin feed. As expected, branching has a strongly negative effect on the CN and it should be minimized. Both, metal-catalyzed di-carbenium C–C cleavage and acid-catalyzed ring contraction/ring opening combination leave branching groups in the product. Similarly, the acid-catalyzed ring opening of perhydrophenanthrene does not result in a significantly higher CN than the initial feed. The possibility of minimizing hydrogen consumption in the CN improvement process by an initial partial hydrogenation followed by ring opening was tested by using phenanthrene and tetralin as probe molecules. In the first reaction strategy, partially hydrogenated phenanthrenes (1-ring and 2-ring aromatics) were followed by ring opening of one of the saturated rings. Although this option would lead to lower overall hydrogen consumption, it results in products of much lower CNs than the ones obtained by full hydrogenation of phenanthrene. Similar results are obtained for tetralin. From this analysis, it is clear that upgrading CN of diesel requires extensive hydrogen consumption. For further upgrading, highly selective hydrogenolysis catalysts are needed in order to minimize branching and therefore obtain high CN products.     

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。     

FCC柴油芳烃选择性开环催化剂研究进展

选择性开环技术可以使芳烃转换成单环烷烃或链烷烃化合物,极大地提高了柴油的清洁度和十六烷值,该技术的核心是开发具有加氢和开环性能的双功能催化剂。本文综述了近年来国内外催化裂化(FCC)柴油芳烃选择性开环催化剂的研究进展,重点讨论了催化剂载体、活性金属及制备方法3个方面对加氢开环反应性能的影响。分析表明载体的酸性和孔道结构、负载活性金属的类型(包括非贵金属和贵金属)及不同的制备方法对催化性能有极大影响。最后对柴油芳烃选择性开环催化剂的研究提出了一些建议,指出今后研究的重点是开发具有适宜酸性和孔结构的新型载体及能够保持活性和稳定性的活性金属组分并加强该领域反应机理的研究。     

Research progress of catalysts for selective hydrogenation of benzene to cyclohexene

目前苯选择加氢制环己烯催化剂已广泛应用于合成纤维工业及其它领域中。本文综述了国内外苯选择加氢制环已烯催化剂的研究现状,重点介绍了活性组分、载体、助剂、制备方法及添加剂对催化剂活性及选择性的影响,分析了其影响原因,并指出了提高环己烯选择性的关键因素,最后在此基础上展望了苯选择加氢催化剂的发展方向。     

Hydrogenation of Aromatic Nitrogroups with Precious Metal Powder Catalysts: Influence of Modifier on Selectivity and Activity

The development of new improved catalysts for the selective hydrogenation of aromatic nitrogroups is still a field of high interest for the chemical industry. Hydrogenation of aromatic nitrogroups to the corresponding aromatic amines is one of the most important applications for precious metal powder catalysts (PMPC). In this paper various commercial PMPC technologies such as palladium, platinum, platinum modified with copper and platinum modified with vanadium on activated carbon powder supports were compared to each other in regard to activity and selectivity for hydrogenation of 1-chloro-2-nitrobenzene. In this reaction, catalysts comprised of vanadium modified platinum on activated carbon showed excellent activities and selectivities towards 2-chloroaniline. Catalyst performance was affected by the ratio of platinum to vanadium and the properties of the carbon. The role of vanadium as an effective modifier to avoid accumulation of hazardous aromatic hydroxylamines was explained.     

苯选择性加氢钌催化剂的研究及应用进展

苯选择性加氢钌催化剂广泛用于合成环己醇/酮,进而制备己内酰胺、己二酸、尼龙、聚酰胺等高附加值的精细化工产品。与传统工艺路线相比,苯选择性加氢技术路线具有安全环保和节能高效的特点,其中,催化反应体系是该技术路线的关键要素。重点概述了近年来苯选择性加氢钌催化剂的研究进展、工业应用现状及市场前景。     

稠环芳烃加氢饱和催化剂研究进展

受共振能、空间位阻和竞争吸附等方面的影响,稠环芳烃末环的吸附活化是其加氢饱和反应的重点和难点之一。本文系统综述了稠环芳烃加氢饱和反应特点及各类稠环芳烃加氢饱和催化剂。分析表明,稠环芳烃吸附活化与其分子自身的属性和催化剂的性质密切相关,调控催化剂中活性金属的电子状态可有效促进稠环芳烃分子的吸附活化。针对常见稠环芳烃加氢饱和催化剂,本文分类阐述了各类稠环芳烃加氢饱和催化剂的活性相结构、活性位点数量和活性金属电子密度的调控方法。分析指出,提高活性组分的分散度和形成活性金属的缺电子状态能够提升催化剂的加氢活性,可通过调节载体的酸性和添加助剂等方法实现。     

贵金属催化剂理性设计在选择性加氢反应中的研究进展

从多相催化的特征出发,综述了多相催化理性设计中典型调控理论和方法的研究进展。同时,以芳香硝基化合物及不饱和醛/酮选择性加氢反应为特征反应,从多相催化剂表面的电子效应、几何效应、界面效应和协同效应等角度进行了全面综述。指出了筛选合适的载体、合成特定尺寸形貌的活性中心、调控金属-载体强相互作用是开发更高效的多相选择性加氢催化剂的重要方向,调控金属-载体强相互作用,优化活性中心的电子效应、空间效应和界面效应,微调N=O及C=O不饱和键的吸附与活化,是实现高效选择性加氢催化体系的理论设计的重要手段。进一步优化氢气的活化裂解方式、活性氢的稳定与迁移,可抑制选择性加氢的副反应。