Selective hydrogenation of benzene to cyclohexene on Ru-based catalysts promoted with Mn and Zn

Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9%...     

Homogeneous mono-and bimetallic catalysts for the oxidation of cyclohexene

In the absence of solvent, the first-row transition-metal acetylacetonate complexes and RuCl₂(PPh₃)₃ give fairly high turnovers for the allylic oxidation of cyclohexene under atmospheric pressure of oxygen. Synergetic effect is observed for the oxidation of cyclohexene by using M(acac)_n−RuCl₂(PPh₃)₃ bimetallic catalysts.     

Conversion of cyclohexene on supported molybdenum- and tungsten-oxide catalysts

The hydro-dehydrogenation of cyclohexene has been studied on: alumina supported Co-, Ni-, Pd-, Pt-promoted and non promoted MoO_x, monometallic Co, Ni and Pt, two - alumina and silica-alumina supported - Ni-promoted WO_x-s. Two groups of characteristically different catalytic behavior of the promoted MoO_x and WO_x samples were identified dependent of the presence and nature of the zerovalent metal on the catalyst surface. No additivity of activities but some interaction between metals and oxides was expressed in the catalytic behavior of the M(8-10)MoO_x catalysts. This revised version was published online in June 2006 with corrections to the Cover Date.     

Selective hydrogenation of benzene to cyclohexene on Ru-basecatalysts promoted with Mn and Zn

Ru-based catalysts promoted with Mn and Zn were prepared by a co-precipitation method. In liquid-phase hydrogenation of benzene, the Ru-Mn-Zn catalysts exhibited superior catalytic performance to the catalysts promoted with Zn or Mn alone. The optimum Mn/Zn molar ratio was determined to be 0.3. With the addition of 0.5 g NaOH, the Ru-Mn-Zn-0.3 catalyst, which was reduced at 150 ? C, afforded a cyclohexene selectivity of 81.1% at a benzene conversion of 60.2% at 5 min and a maximum cyclohexene yield of 59.9% at 20 min. Based on characterizations, the excellent performance of Ru-Mn-Zn catalyst was ascribed to the suitable pore structure, the appropriate reducibility and the homogenous chemical environment of the catalyst.     

Hydrogenation of acetone on technetium catalysts

The catalytic properties of supported mono- and bimetallic catalysts of the Tc/support, M/support, and M-Tc/support types (M=Pt, Pd, Rh, Ru, Ni, Re, Co; supports are γ-Al₂O₃, MgO, SiO₂) were investigated in the acetone hydrogenation. The main products of this reaction are isopropyl alcohol and propane. The catalytic activity in the acetone hydrogenation of the metals studied decreases in the consequence Pt>Tc≈Rh>Pd>Ru >Ni≈Re>Co (with γ-Al₂O₃ as the support). The influence of support nature on the catalytic activity was investigated for the Rh−Tc system as an example. A nonadditive increase in the catalytic activity of Rh−Tc/γ-Al₂O₃ in comparison with monometallic catalysts was found. The state of the surface of the catalysts was characterized by the UV-VIS diffuse reflectance spectra. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 414–417, March, 1998.     

Preparation, characterization, activity and selectivity of highly loaded oxide promoted ruthenium catalysts for selective hydrogenation of benzene to cyclohexene

Summary The influence of promoters and precipitants of the catalyst precursor on the activity and selectivity of the hydrogenation of benzene to cyclohexene catalyzed by highly loaded oxide-promoted Ru/ZrO₂catalysts, carried out in a tetraphase reactor (in the presence of an aqueous solution of ZnSO₄), at 423 K and 5 Mpa, was studied. The effect of hydrogen diffusion on the reaction kinetics and on the selectivity has been taken into consideration, the internal pore diffusion being actually the limiting step. Hydrogen chemisorption measurements indicate that the catalyst activity is not influenced by the Ru dispersion, but rather by weakly chemisorbed species.     

助剂Fe和反应修饰剂修饰的Ru催化剂上苯选择加氢制环己烯

共沉淀法制备了Ru-Fe(x)催化剂,并利用X射线衍射(XRD)、X射线荧光光谱(XRF)、N2物理吸附和透射电镜等手段对催化剂进行了表征.结果表明,Ru-Fe(x)催化剂中助剂Fe以Fe3O4形式存在.单独Fe3O4并不能提高Ru催化剂的环己烯选择性.但在加氢过程中Fe3O4可与反应修饰剂ZnSO4反应生成(Zn(OH)2)3(ZnSO4)(H2O)x(x=1 or 3).化学吸附的(Zn(OH)2)3(ZnSO4)(H2O)x(x=1 or 3)在提高Ru催化剂环己烯选择性中起着关键作用.此外,Ru-Fe(x)催化剂的性能还与浆液中的Zn2+浓度和pH值有关.在0.61 mol/L ZnSO4溶液中Ru-Fe(0.47)催化剂不但给出了56.7%的环己烯收率,而且具有良好的稳定性和重复使用性能.化学吸附在Ru表面的Fe2+同样能提高Ru催化剂的环己烯选择性.在0.29 mol/L和0.61 mol/L FeSO4溶液中Ru-Fe(0.47)催化剂上化学吸附Fe2+量近似,性能近似.因为Fe2+和Zn2+性质的差异,在0.29 mol/L和0.61 mol/L FeSO4溶液中Ru-Fe(0.47)催化剂的环己烯选择性分别低于在同浓度的ZnSO4溶液中的.     

聚乙二醇稳定的RuB纳米粒子催化苯选择加氢为环己烯的性能研究

PEG稳定的RuB纳米粒子对苯选择加氢制备环己烯显示出良好的催化性能,在不添加硫酸锌的条件下,该体系催化的苯选择性加氢中,环己烯收率高达29%。这一体系的高催化性能是由于PEG稳定的RuB纳米粒子,使催化剂表面的亲水性增强,提高了环己烯的选择性。     

负载型钌基催化剂催化苯选择加氢合成环己烯

沉淀法制备的钌基催化剂催化苯选择加氢的工艺已成熟并工业化,新型高活性、高选择性的负载型催化剂因其独特的性质成为目前新的研究方向.本文重点讨论了负载型钌基催化剂制备过程中载体种类、载体修饰、活性组分和负载量等因素对催化剂活性、选择性等方面的影响,同时也介绍了反应温度、压力、转速和添加剂等因素对催化剂活性、选择性等方面的影响.     

Ru/ZrO_2催化剂在苯部分加氢反应中的粒径效应

采用多元醇还原法将2.4~5.4 nm范围内粒径均一、尺寸可控的Ru纳米粒子负载在ZrO2上,研究了Ru的粒径对Ru/ZrO2催化剂上苯部分加氢性能的影响.采用紫外-可见吸收光谱(UV-Vis)、N2物理吸附、H2化学吸附、H2-程序升温脱附(H2-TPD)、粉末X射线衍射(XRD)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等手段对催化剂进行了系统的表征.研究表明,用于还原的醇的种类及添加剂乙酸钠的浓度对Ru粒径有显著影响.在苯部分加氢反应中,Ru/ZrO2催化剂有明显的粒径效应.随着Ru粒径的增大,苯的转换频率(TOF)提高,环己烯初始选择性(S0)则呈火山型变化趋势,选择性最高时的Ru粒径为4.4 nm.1,2-丙二醇还原得到的Ru/ZrO2催化剂上S0及环己烯得率最高,分别可达82%和39%.结合催化剂的表征和加氢结果,讨论了Ru粒径影响苯部分加氢活性和选择性的原因.     

Hydrogenation of carbon monoxide over technetium catalysts

Supported Tc catalysts are active in CO hydrogenation, their activity depending on the nature of the support. The reaction proceeds predominantly toward methane formation. All catalysts studied yielded very little C₂ and C₃ hydrocarbons. The thermal desorption data indicate that the CO strongly bound to the substrate is responsible for CH₄ formation.Institute of Physical Chemistry, Russian Academy of Sciences, 117915 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 7, pp. 1507–1511, July, 1992.     

蜂窝陶瓷整体反应器内苯选择加氢制环己烯

 研究了Ru/ZrO2蜂窝陶瓷整体催化剂对苯液相选择加氢制环己烯反应的催化性能,考察了催化剂载体、活性组分含量、预处理条件、反应温度、反应压力、水和硫酸锌水溶液等对该反应的影响. 结果表明,整体催化剂不经预还原就可以直接进行苯液相加氢反应; 反应物中不加水或其它无机添加剂时环己烯的选择性为0,水或硫酸锌水溶液的加入大大降低了反应活性,但环己烯的选择性显著提高,约达到20%; 反应物中水和苯有最优配比,以保证最佳的环己烯选择性和收率; 反应温度在413～443 K,反应压力为3～4 MPa,硫酸锌浓度为0.1 mol/L时,反应结果较好.     

端羟基聚环氧环己烷的合成

端羟基聚环氧环己烷的合成;端羟基聚环氧环己烷;环氧环己烷;阳离子聚合     

聚合物负载的钯-咪唑催化烯烃加氢

A polymer-supported palladium-imidazole catalyst was used to catalyze the hydrogenation of various olefins under mild conditions. The rate of hydrogenation was studied. The effects of factors such as substrate concentration,catalyst concentration,partial pressure of hydrogen and temperature on initial rate of reaction of selected olefins were investigated. A mechanism for the reaction was proposed from the rate equation. The effects of the solvent and structure of the olefin on the rate of hydrogenation were investigated. The catalyst showed good reusability without any leaching of metal from the support. The homologous analog of the polymer-supported catalyst could not be used as catalyst for the hydrogenation of olefins in methanol because there was precipitation of the metal during reaction.     

RuB-PVP胶态催化剂的制备及苯选择加氢性能研究

系统研究了制备时间、Ru/PVP(聚乙烯吡咯烷酮)比及钌浓度对PVP稳定的RuB胶态催化剂粒径及分布的影响; 制备了粒径在1.3～3.9 nm的RuB-PVP催化剂, 研究了不同粒径的催化剂对苯选择加氢反应的影响. 结果表明RuB粒径越小, 催化剂的苯选择加氢性能越好. 在粒径为1.3 nm的RuB-PVP催化剂上, 环己烯得率达到16.8%. 在无机添加剂ZnSO₄的存在下, 环己烯得率可进一步提高至23.2%. 在相同实验条件下, 无PVP稳定的RuB催化剂上的苯选择加氢性能则远低于RuB-PVP胶态催化剂.     

助剂前体ZnSO_4浓度对苯选择加氢制环己烯Ru-Zn催化剂性能的影响

共沉淀法制备了Ru-Zn催化剂,在ZrO_2作分散剂下考察了助剂前体ZnSO_4浓度对苯选择加氢制环己烯Ru-Zn催化剂性能的影响.并用X-射线衍射(XRD)、X-射线荧光光谱(XRF)、N_2-物理吸附、透射电镜(TEM)和X-射线光电子能谱(XPS)等手段对催化剂进行了表征.结果表明,当ZnSO_4前体浓度低于0.10 mol/L时,Ru-Zn催化剂中Zn以ZnO形式存在,在加氢过程中ZnO可以与反应修饰剂ZnSO_4反应生成(Zn( OH)_2)_3(ZnSO_4)(H_2O)_3盐.继续增加ZnSO_4前体浓度,催化剂中Zn以ZnO和NaZn_4(SO_4)(Cl)(OH)_6·6H_2O盐存在,在加氢过程中ZnO和NaZn_4(SO_4)(Cl)(OH)_6·6H_2O盐可以与反应修饰剂ZnSO_4反应生成(Zn( OH)_2)_3(ZnSO_4)(H_2O)_5.(Zn( OH)_2)_3(ZnSO_4)(H_2O)_x(x=3或5)盐的Zn~(2+)可以转移金属Ru的部分电子.因此,随ZnSO_4前体浓度的增加,(Zn( OH)_2)_3(ZnSO_4)(H_2O)_x的量逐渐增加,金属Ru失电子越多,催化剂活性越低,环己烯选择性越高.0.08 mol/L ZnSO_4前体制备Ru-Zn催化剂给出了59.1%的环己烯收率,而且该催化剂具有良好的重复使用性能和稳定性.     

非晶Ru-C0/ZrO2催化苯加氢制备环己烯

催化加氢反应;非晶态;非晶Ru-C0/ZrO2催化苯加氢制备环己烯     

非晶态合金Ru基催化剂在苯选择加氢中的应用进展

化学还原法制备的非晶态合金Ru基催化剂融合了纳米粒子和非晶态合金的结构特征,在苯选择加氢反应中表现出高活性和高环己烯选择性;尤其是负载型非晶态合金Ru基催化剂,具有贵金属利用率高和易于工业化等优点,有着明显的竞争优势,本文综述了苯选择加氢的热力学和动力学特征,非晶态合金催化剂结构和组成及其对催化性能的影响;总结了催化工...     

Study on the Nanosized Amorphous Ru-Fe-B/ZrO2 Alloy Catalyst for Benzene Selective Hydrogenation to Cyclohexene

A novel nanosized amorphous Ru-Fe-B/ZrO2 alloy catalyst for benzene selective hydrogenation to cyclohexene was investigated. The superior properties of this catalyst were attributed to the combination of the nanosize and the amorphous character as well as to its textural character. In addition, the concentration of zinc ions, the content of ZrO2 in the slurry, and the pretreatment of the catalyst were found to be effective in improving the activity and the selectivity of the catalyst.