纳米Ru催化剂催化喹啉加氢反应

制备了高分散性负载型5%Ru/C催化剂,采用X射线衍射、X射线光电子能谱和高分辨透射电镜对催化剂进行了表征.结果表明,所制得的5%Ru/C催化剂分散度高,金属钌的平均粒径小于5nm.在喹啉加氢反应中,催化剂显示出很高的催化活性和生成1,2,3,4-四氢喹啉的选择性,但未检测到十氢喹啉生成.补加新鲜催化剂后,1,2,3,4-四氢喹啉可全部转化为十氢喹啉.对喹啉加氢机理进行了探讨.     

Ru/ZrO2·xH2O催化喹啉加氢反应

制备了负载型催化剂Ru/ZrO2·xH2O, 并用XRD、XPS和TEM对催化剂进行了表征, 所制得的催化剂金属钌的平均粒径约为3.8 nm. 在2 MPa和40 ℃的温和条件下, 以水为溶剂时, Ru/ZrO2·xH2O催化喹啉加氢生成1,2,3,4-四氢喹啉的选择性达98.0%, 而且表现出较强的抗氮中毒能力, 催化剂循环使用性能稳定. 对喹啉加氢反应中的催化反应机理进行了探讨.     

Ru/ZrO2·xH2O催化喹啉加氢反应

制备了负载型催化剂Ru/ZrO2·xH2O,并用XRD、XPS和TEM对催化剂进行了表征,所制得的催化剂金属钌的平均粒径约为3.8 nm.在2MPa和40℃的温和条件下,以水为溶剂时,Ru/ZrO2·rH2O催化喹啉加氢生成1,2,3,4-四氢喹啉的选择性达98.0%,而且表现出较强的抗氮中毒能力,催化剂循环使用性能稳定.对喹啉加氢反应中的催化反应机理进行了探讨.     

多孔SiO_2·xH_2O负载RuB纳米粒子催化喹啉加氢反应

通过水解,聚乙烯吡咯烷酮(PVP)保护,NaOH刻蚀等方法制备了多孔及富含表面羟基的SiO2·xH2O负载的RuB催化剂RuB/SiO2·xH2O,并用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、傅里叶变换红外(FT-IR)光谱和BET(Brunauer-Emmett-Teller)等手段对该催化剂进行了表征.结果表明该催化剂具有良好的抗中毒能力,在3.0MPa的H2压力和80℃的温和反应条件下,喹啉的转化率高于95%,生成1,2,3,4-四氢喹啉的选择性高于97%.并系统研究了表面羟基和溶剂对催化剂性能的影响,发现以水为溶剂时,RuB/SiO2·xH2O对喹啉加氢反应展示出较高的活性和对1,2,3,4-四氢喹啉较高的选择性,催化剂能够多次循环使用.这一体系的优异催化性能归属于载体表面羟基和水的协同作用.     

负载型纳米贵金属催化剂催化吡啶及其衍生物的加氢反应

 制备了负载型高分散的纳米贵金属催化剂和含Ru的双金属催化剂,并考察了催化剂对吡啶及其衍生物加氢反应的催化性能. 结果表明, 5%Ru/C催化剂对吡啶加氢反应的催化活性高于5%Pd/C, 5%Pt/C和5%Ir/C. 在100 ℃, 3.0 MPa, 1 h和Ru/吡啶摩尔比=2.5/1000 的条件下, 5%Ru/C催化吡啶加氢的转化率大于99.9%, 生成哌啶的选择性为100%. 催化剂重复使用5次后,活性和选择性无明显下降. 在Ru催化剂中加入少量的Pd和Ir后催化剂活性没有明显的变化. 采用X射线衍射、高分辨透射电镜和X射线光电子能谱对还原后的5%Ru/C催化剂进行表征,结果表明Ru以高分散金属态存在,其平均粒径小于5 nm. 不同底物的加氢反应活性为: 吡啶≈2-甲基吡啶>2,6-二甲基吡啶>3-甲基吡啶>4-甲基吡啶>3,5-二甲基吡啶>2-甲氧基吡啶.     

金属有机框架与Pt粒子复合材料催化喹啉选择性加氢性能研究※

喹啉选择性加氢制备1,2,3,4-四氢喹啉在药物、农药和精细化学品等的生产中表现出巨大的应用潜力, 引起了广泛关注. 该反应通常要在高温、高压等苛刻条件下进行, 温和条件下对其选择性加氢仍具有很大挑战. 本工作以氯化锆为金属盐和2,2'-联吡啶-5,5'-二羧酸为配体制备金属有机框架材料UiO-67N, 以Pt纳米粒子为活性组分, 可控制备出具有三明治结构的UiO-67N@Pt@UiO-67N复合催化剂, 同时可调控其壳层厚度为11, 28和42 nm. 利用X射线衍射分析、扫描电子显微镜、透射电子显微镜、X射线光电子能谱、电感耦合等离子发射光谱仪、傅里叶变换红外光谱仪和氮气吸脱附测试对催化剂进行了系统表征. 研究发现, 相比于UiO-67而言, UiO-67N可以显著提高Pt纳米粒子催化喹啉选择性加氢的性能, 且UiO-67N@Pt@UiO-67N在常温下实现了高转化率(>99%)和高选择性(>99%)催化喹啉加氢制备1,2,3,4-四氢喹啉; 随着壳层厚度的增加, 其催化活性会显著降低, 但选择性保持不变. 以喹啉的衍生物作为底物, 三明治结构催化剂也可展现出优异的活性和选择性加氢性能. 相比于负载型催化剂, 三明治结构复合催化剂具有优异的循环稳定性. X射线光电子能谱和红外光谱分析表明, UiO-67N与Pt纳米粒子间的电子转移, 以及与喹啉间的强界面相互作用有助于提高催化剂的性能.     

离子液体介质中钌膦配合物催化的喹啉加氢反应

首次在亲水性离子液体[Rmim][p-CH3C6H4SO3](1-烷基-3-甲基咪唑对甲苯磺酸盐,R=甲基、乙基、正丁基、正己基和正辛基)中,以水溶性的[RuCl2(TPPTS)2]2(TPPTS:间磺酸钠基三苯基膦)为催化剂,分别考察了温度、压力、不同的离子液体、水和碘的加入等因素对喹啉加氢反应的影响.在100℃和氧气压力为3.0 MPa时,喹啉加氢生成1,2,3,4-四氧喹啉的选择性超过99%,转化率达到95.3%.利用环己烷萃取反应产物,即可实现催化剂与产物的分离,催化剂循环使用6次后反应的转化率仍可达86.0%.     

RuB-PEG催化剂对喹啉加氢性能研究

以PEG做稳定剂制备了RuB非晶态纳米催化剂.采用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电镜(TEM)和等离子发射光谱(ICP)对催化剂进行了表征.结果表明,RuB以高分散态存在,其中金属钌的平均粒径约为2.4 nm.该研究考察了聚合度、溶剂、催化剂用量、催化剂中硼钌比、压强和添加剂等因素对喹啉加氢反应...     

Ni2P和MoS2催化剂在喹啉加氢脱氮反应中的协同效应

设计实验证明了Ni₂P和MoS₂催化剂在喹啉加氢脱氮反应中存在协同效应,该协同效应能够用氢溢流遥控模型理论解释。Ni₂P//MoS₂的协同因子随反应温度升高而减小,并且略微大于相同反应条件下NiS_x//MoS₂的协同因子。Ni₂P产生的溢流氢能够提高MoS₂催化剂上加氢活性位的数量,促使Ni₂P//MoS₂催化体系增加1,2,3,4-四氢喹啉和5,6,7,8-四氢喹啉加氢生成十氢喹啉的速率,提高其脱氮活性;因此,Ni₂P对MoS₂催化剂是很好的助剂。     

Pd/C促进的四氢异喹啉高选择性部分脱氢(英文)

采用K3PO4?3H2O修饰的Pd/C为催化剂实现了取代四氢异喹啉高选择性部分脱氢,并成功地避免了当量有害氧化剂的使用.多相催化剂Pd/C对四氢异喹啉化合物具有催化脱氢活性,但反应选择性较差,同时产生完全脱氢的芳构化产物异喹啉.而K3PO4?3H2O修饰的Pd/C催化剂能有效提高脱氢反应的化学选择性,在最优条件下可获得最高89%的分离收率.这为取代3,4-二氢异喹啉的合成提供了一种简便、高原子经济性和高化学选择性的反应途径.此外,该多相催化剂可回收循环使用多次,且活性和选择性基本保持不变.     

High-Performance Supported Ru Catalysts for the Aqueous-Phase Hydrogenation of Levulinic Acid to γ-Valerolactone

γ-Valerolactone (GVL) can be obtained by efficient hydrogenation of levulinic acid using ruthenium-based catalysts in an aqueous medium. This paper reports an in-depth study on the activity and selectivity of Ru catalysts supported on zirconia-alumina, focusing on the effect of Ru concentration (0.5, 1.5 and 3 wt. % of Ru) and the selection of operational reaction variables. The results showed that the activity strongly depends on the number and oxidation state of the supported ruthenium particles. The most active catalyst, Ru3/ZA, presented the highest number of nanometric particles of zerovalent Ru and the highest number of acid sites. This catalyst gave ca. 100 % selectivity towards GVL, at high conversion of levulinic acid (over 99 %) under the best operating conditions evaluated (120 °C, 3 MPa H₂ pressure, 1 h of reaction, and 0.1 g of catalyst). In addition, this catalyst kept high levels of conversion and selectivity after successive reuse cycles.     

In situ preparation of ultrafine Ru nanocatalyst supported on nitrogen-doped layered double hydroxide by nitrogen glow discharge plasma for catalytic hydrogenation of N-ethylcarbazole

Ultrafine Ru nanoparticles (RuNPs) supported on nitrogen-doped layered double hydroxide (Ru/LDH) were in situ prepared by nitrogen glow discharge plasma (nGDP) without adding any chemical reducing agents or stabilizers. The as-synthesized Ru/LDH catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy. During treatment with nGDP, the reduction of Ru³⁺ and nitrogen doping were carried out simultaneously. The resulting RuNPs has a narrow particle size distribution of 1.41–2.61 nm, an ultrafine average particle size of 1.86 nm, and were uniformly dispersed on nitrogen-doped LDH. The complexation of RuNPs and O/N-containing functional groups on LDH improve the catalytic activity and stability of Ru/LDH. The catalyst exhibited excellent properties for the hydrogenation reaction of N-ethylcarbazole (NEC). The conversion of NEC and the selectivity of 12H-NEC were 100% and 99.06% for 1 hr at 120°C and 6 MPa H₂, respectively. The mass hydrogen storage capacity was 5.78 wt%. The apparent activation energy was 35.78 kJ/mol.     

Study of a Ru-La/Zr02 Catalyst Prepared by Precipitation Method for Selective Hydrogenation of Benzene to Cyclohexene

A Ru-La/ZrO2 catalyst was prepared by the precipitation method, in which Ru was an active component, La was a promoter and ZrO2 was a dispersant. Comparing with the catalyst prepared by the chemical reduction method, the Ru-La/ZrO2 exhibited higher activity and better selectivity. At 140 ℃ and hydrogen pressure of 5 MPa, the C6H10 selectivity reached 70% at a C6H6 conversion of 35% for a reaction time was 5 min and the total La/Ru loading was 10%. Textural parameters of the catalyst were obtained by physical adsorption, BET surface area and specific pore volume measurements. The catalyst sample gave a BET area of 41 m2/g and a specific pore volume of 1.1 cm^3/g, and the most probable pore distribution was located at 5 to 10 nm. H2-TPR measurements showed that ruthenium oxide could be reduced to its metallic state at about 403 K. XRD determinations indicated that ruthenium and lanthanum were highly dispersed on the zirconia. A significant advantage of the Ru-La/ZrO2 catalyst is that it can be used directly in its unreduced state for the selective hydrogenation of benzene.     

Ru-[bmim]BF4 的制备及催化苯选择加氢反应性能

以离子液体1-丁基-3-甲基咪唑四氟硼酸盐([bmim]BF4)-水混合溶剂为介质,采用化学还原法制备了Ru-[bmim]BF4催化剂,并利用紫外-可见光谱、红外光谱、透射电镜、X射线衍射和X射线光电子能谱对催化剂进行了表征.结果表明,Ru在[bmim]BF4中分散较好,粒径~2nm,且离子液体中咪唑阳离子与部分Ru形成了金属卡宾配合物.利用苯选择加氢反应对该催化剂性能进行了评价,发现Ru-卡宾配合物存在时,催化剂活性较低,但环己烯选择性较高.在本文反应条件下,苯转化率为12.2%,环己烯选择性为40.5%.重复使用该催化剂时,由于Ru-卡宾配合物在反应中转变为Ru0,其催化活性增加,但环己烯选择性下降.继续多次使用该催化剂,其性能基本保持稳定.     

Study of a Ru-La/ZrO_2 Catalyst Prepared by Precipitation Method for Selective Hydrogenation of Benzene to Cyclohexene

1. Introduction Cyclohexene as an important intermediate prod- uct is widely used in chemical productions. The process of selective hydrogenation of benzene to cyclo- hexene has been an important research topic in green chemistry owing to its atomic economy and clean production [1]. In order to attain greater economic benefits, researchers are searching for a new catalytic system that is high in activity and selectivity, simple in technology, and low in cost. In this respect, some progresses h…     

Effect of decomposition of catalyst precursor on Ni/CeO2 activity for CO methanation

CO methanation on Ni/CeO₂ has recently received increasing attention. However, the low-temperature activity and carbon resistance of Ni/CeO₂ still need to be improved. In this study, plasma decomposition of nickel nitrate was performed at ca. 150°C and atmospheric pressure. This was followed by hydrogen reduction at 500 °C in the absence of plasma, and a highly dispersed Ni/CeO₂ catalyst was obtained with improved CO adsorption and enhanced metal-support interaction. The plasma-decomposed catalyst showed significantly improved low-temperature activity with high methane selectivity (up to 100%) and enhanced carbon resistance for CO methanation. For example, at 250°C, the plasma-decomposed catalyst showed a CO conversion of 96.8% with high methane selectivity (almost 100%), whereas the CO conversion was only 14.7% for a thermally decomposed catalyst.     

Ni-Cu/Al_2O_3催化剂上顺酐液相选择加氢制丁二酸酐反应性能

以Al2O3为载体,采用等体积浸渍法制备了一系列Ni-Cu/Al2O3催化剂,用于顺酐液相加氢反应,并结合低温N2物理吸-脱附、H2程序升温还原、H2程序升温脱附、X射线衍射、CO程序升温表面反应等表征结果,详细考察了催化剂中Cu含量对其催化性能的影响.结果表明,Cu的引入提高了活性组分Ni的分散度,促进了催化剂上C=C的加氢活性;同时,由于Ni-Cu双金属间的相互作用,明显抑制了催化剂表面C=O的加氢.当Cu含量为7%时,催化剂上顺酐加氢定向合成丁二酸酐的活性最高.在210oC,H2压力5.0MPa的条件下反应40min时,顺酐转化率与丁二酸酐选择性均达100%.     

Catalytic hydrogenation of 1,4-phenylenediamine to 1,4-cyclohexanediamine

Catalytic hydrogenation of 1,4-phenylenediamine to 1,4-cyclohexanediamine using Ru/Al₂O₃ as a catalyst was carried out in water, and the results were compared with those in isopropanol and SC-CO₂. 80% 1,4-phenylenediamine conversion with 87% selectivity to 1,4-cyclohexanediamine was achieved on 5% Ru/Al₂O₃ catalyst at 90°C and H₂ pressure of 4 MPa. The hydrogenation of 1,4-phenylenediamine is influenced by the solvent. A systematic study of the hydrogenation of 1,4-phenylenediamine revealed that the reaction was consecutive. The longer the time, the lower was the CHDA selectivity. Also, the reaction temperature was an important parameter and played a vital role in preventing the formation of side products.