分子间醇的催化胺化反应的铜基催化剂的筛选与表征

以乙醇和哌嗪催化胺化合成N-乙基哌嗪的反应为模型,对分子间醇的催化胺化反应进行了研究。制备了一系列的铜基催化剂用于此反应,筛选得到了Cu-Cr-Zn/γ-Al2O3催化剂,在最佳反应条件下,乙醇的转化率达93%,N-乙基哌嗪的选择性达90%以上;而且在100 h的寿命实验中,N-乙基哌嗪的选择性保持在86%以上。采用X射线衍射、X射线光电子能谱和程序升温还原等对催化剂进行了系列表征,提出单质铜最有可能是催化剂的活性中心,且活性组分锌的添加能够有效地分散催化剂表面的铜,从而提高了催化剂的活性和稳定性。     

Synthesis,characterization and catalytic properties of polypyrrole-supported catalysts

Polypyrrole, a conductive polymer, was used as support of noble metals, namely, copper and palladium, for application in heterogeneous catalysis. Catalysts were characterized by TEM coupled with EDS and XRD. Their activity and selectivity were determined in the reduction of nitrate and intermediate nitrite in water under 1 bar of hydrogen and at room temperature. In nitrite reduction, these novel catalysts demonstrated a better activity and a higher selectivity towards nitrogen formation than their Pd/Al₂O₃ counterpart. On the other hand, the bimetallic catalyst tested for nitrate reduction showed an activity similar to the one of a classical Pd–Cu/Al₂O₃ catalyst, but no intermediate nitrite was observed.     

Synthesis, characterization and catalytic activity of ruthenium-doped cobalt catalysts

Cobalt-based catalysts doped with different amounts of ruthenium supported on Zr-MSU type materials were studied in the hydrogenation and hydrogenolysis/hydrocracking of tetralin at different temperatures. The catalytic tests were carried out in a high-pressure fixed-bed continuous-flow stainless steel catalytic reactor operating at a pressure of 6.0 MPa. Textural, structural, acidic and metallic properties were studied by XRD, XPS, H₂-TPR, NH₃-TPD and Elemental Chemical Analysis. Five catalysts were prepared with 10 wt% of cobalt and a ruthenium loading ranging from 0.5 to 5 wt%, along with a monometallic ruthenium catalyst with 3 wt% of metal, for comparison. From catalysts characterization, no interaction between cobalt and ruthenium can be established, however, the presence of ruthenium influences the reducibility of cobalt.

Ruthenium-doped catalysts not only improve the catalytic activity of monometallic cobalt and ruthenium ones, but also ruthenium acts as a trap for sulphur organic molecules, preserving cobalt particles from sulphur poisoning and thus maintaining their high hydrogenation activity. The catalyst with a ruthenium loading of 3 wt% is found to be the most active, both, with or without sulphur in the feed. The most striking improvement of ruthenium-doped catalyst properties is their greater resistance to sulphur molecules than in the case of monometallic cobalt catalysts, which are otherwise rapidly deactivated under the same experimental conditions.     

脂肪醇制脂肪叔胺胺化催化剂的研究与开发

综述了近20年醇法胺化制脂肪叔胺催化剂的发展概况，介绍了催化剂的作用机理、制备方法、性能评价及影响因素等，其中以铜镍和铜铬系列的多元催化剂性能较好。稀土元素和锌的加入提高了铜镍催化剂的选择性，从微观上阐述了催化胺化反应中锌对铜镍价态的影响，并讨论了影响催化剂稳定性的因素。     

Synthesis and characterization of carbon-supported nanoparticles for catalytic applications

Metallic and carburized tungsten nanoparticles have been prepared using WCl₆ as precursor. The synthesis steps lead from tungsten hexachloride to tungsten carbide following the sequence WCl₆ → W⁰ → α-W₂C → WC. These different compounds have been mainly characterized by X-ray diffraction, TEM observations and adsorption measurements. The total reduction of tungsten hexachloride can be completed at T = 973 K. The carburizing of the metallic lattice into carbide WC is observed at 1223 K although incomplete. At this temperature, crystal growth phenomena appear which are not desired for catalysis applications. The synthesis of nanoparticles supported on activated carbon is accompanied by a decrease of the specific surface area of samples, especially during high temperature carburizing.     

三核铜配合物的合成、表征及其催化性能

采用溶剂热法合成了以三核碘化亚铜（CuI）四面体结构为活性中心的硅氢加成反应催化剂,探讨了物料比对产物收率的影响。结果说明了当配体与碘化亚铜的摩尔比为1：6时,产物收率最高。通过元素分析、傅里叶红外光谱分析、X射线光电子能谱分析、X射线单晶体衍射分析、紫外可见光光谱分析、热失重分析对配合物的化学组成、空间结构及性能进行表征,并进一步通过甲基苯基乙烯基树脂和甲基苯基含氢硅油的硅氢加成反应进行催化固化效果验证。结果说明了在催化剂填加量为0.04%、固化温度为150℃的优化条件下反应24h,共混体系固化效果最佳。该配合物对硅氢加成反应具有很好的催化性能,并且原料成本低、制备方法简单、晶体颗粒方便储存,有望解决硅氢加成反应中贵金属催化剂的高成本问题。     

Synthesis,characterization and catalytic methanation performance of modified kaolin-supported Ni-based catalysts

Kaolin as a raw material for mesoporous support was firstly modified by calcination, acid treatment, and then was used to prepare nickel catalysts. The amount of alumina which was activated in kaolin during thermal treatment and then leached out in the acid was different. XRD pattern of the kaolin calcined at 600℃ or 900℃ exhibited only the diffraction peaks for amorphous silica and quartz while that calcined at 1100℃ showed obvious peaks for γ-Al₂O₃. Therefore, the nickel-based catalysts exhibited different physic-chemical properties. Atmospheric syngas methanation over the catalysts clarified an activity order of CA-1100 > CA-900 > CA-1400 > CA-600 > KA ≈ 0 at temperatures of 350-650℃ and a space velocity of 120 L·g^-1·h^-1. Metallic nickel with small diameter which has medium interaction with the modified kaolin and is well dispersed on the support would have reasonably good activity and carbon-resistance for syngas methanation.     

Gold/hydroxyapatite catalysts: Synthesis, characterization and catalytic activity to CO oxidation

This work reports the synthesis, characterization and catalytic activity for CO oxidation of gold catalysts supported on calcium hydroxyapatite. On both, the hydroxyapatite support and the gold-supported hydroxyapatite catalyst, the CO conversion shows a peak near 100% of conversion at room temperature. The generation of structural vacancies by interaction of CO with the solid provokes the formation of peroxide species in the presence of gaseous oxygen, which seems to be responsible of this high conversion of CO at room temperature. Moreover, the influence of the pre-treatment temperature on the activity has been observed and related with the elimination of carbonate species and the generation of structural defects in the apatite structure, which are able to modify the gold oxidation state.     

Synthesis, characterization and catalytic properties of benzyl sulphonic acid functionalized Zr-TMS catalysts

Mesoporous zirconium hydroxide, Zr-TMS (zirconium hydroxide with mesostructured framework; TMS, transition metal oxide mesoporous molecular sieves) catalyst has been prepared through the sol–gel method and functionalized with benzyl sulphonic acid (BSA) using post-synthesis route without destroying the mesoporous structure. The benzyl group anchored Zr-TMS (B-Zr-TMS/≡Zr–O–CH₂–Φ) was achieved by etherification reaction of Zr-TMS with benzyl alcohol at 80 °C using cyclohexane as solvent. Further, B-Zr-TMS was subjected to sulphonation reaction with chlorosulphonic acid (ClSO₃H) at 70 °C using chloroform as solvent to yield BSA-Zr-TMS (≡Zr–O–CH₂–Φ–SO₃H). Maximum sulphonic acid (–SO₃H) loading was optimized with respect to time of functionalization and concentration of ClSO₃H. Functionalization was carried out by loading the maximum amount of benzyl group over Zr-TMS and varying the concentration of –SO₃H. The synthesized materials have been characterized by powder XRD, FT-IR, elemental analysis, N₂ adsorption–desorption and TPD of ammonia. The catalytic activity of the synthesized catalyst has been performed in liquid phase benzoylation of diphenyl ether to 4-phenoxybenzophenone (4-PBP) using benzoyl chloride as benzoylating agent at 160 °C under atmospheric pressure. The same reaction was carried out by sulphated zirconia (SO₄²⁻/ZrO₂) and found very poor activity.     

Synthesis,characterization and catalytic behavior of AlTf/UVM-7 as new green catalysts for the glycols etherification reactions

Bimodal porous Al–UVM-7 system materials with different Si-to-Al ratios were prepared using the Atrane route. These were converted in strong acid heterogeneous AlTf-based catalysts after the treatment with methanolic solutions of triflic acid. The materials so obtained were used as catalysts for the conversion of ethylene glycol (EG) and propylene glycol (PG) with octanol under solvent-free conditions. The process is selective to short ethoxylated structures resulting in the corresponding monoethers. While the conversion of EG and PG was very high (>94%) irrespective of the support characteristics, 1-octanol was transformed only in low degree (3–35%), and its conversion depends on both the Si/Al molar ratio and the catalyst texture (Al–UVM-7 or AlTf–UVM-7). Recyclable experiments showed the catalysts are stable and the reuse occurred without changes in the chemical composition.     

负载型铜催化剂的三效催化性能及应用

采用等体积浸渍法制备了以CeO2、Al2O3以及CeO2/Al2O3为载体的负载型CuO催化剂及其老化样品,采用XRD和H2-TPR等技术对老化前后催化剂的结构和氧化还原性能进行了表征。结果显示,对于老化前后的CuO/CeO2/Al2O3催化剂,CuO均能够很好地分散在载体上,即CeO2/Al2O3具有较好的抗烧结能力。考察了不同载体、CeO2和CuO负载质量分数对CuO/CeO2/Al2O3样品三效催化性能的影响,并将制得的CuO/CeO2/Al2O3催化剂与贵金属三效催化剂Pd/CeO2/Al2O3相比较,考察了高温焙烧之后的CuO/CeO2/Al2O3老化样品对CO、C3H6和NO的三效催化性能。结果表明,以10%CeO2/Al2O3为载体,CuO负载质量分数为7%的CuO/CeO2/Al2O3催化剂对汽车尾气脱除催化反应具有较高的催化活性;与Pd/CeO2/Al2O3比较,CuO/CeO2/Al2O3具有更好的低温活性,CO、HC和NOx的起燃温度分别为130℃、250℃和250℃,在350℃三种原料气的转化率均达到90%;老化实验表明,CuO/CeO2/Al2O3具有较好的抗老化性能。     

杂原子磷铝分子筛BSiAPO-5的合成结构及催化性能的研究

用水热合成法合成了一种硼-硅磷铝分子筛,通过化学分析、测定晶胞参数及用XRD,MAS—NMR方法进行表征,证实了硼、硅原子进入了分子筛骨架,并且具有和AIPO4-5相似的结构;用IR,NH3-TPD表征方法测出了它的酸性,测定结果表明,它具有L酸和B酸中心,以中等强度酸为主。在苯与烯烃烷基化反应中表现出良好的催化活性和长寿命,并且对2-LAB和3-LAB具有高选择性,有可能替代HF成为一种环境友好的新型催化剂。     

Heterogenized nickel catalysts for propene dimerization: Support effects on activity and selectivity

Ni–SiO₂ and Ni-[Si]–MCM-41 are synthesized by grafting Ni(MeCN)₆(BF₄)₂ onto SiO₂ (nonporous) and MCM-41 (mesoporous). The catalytic properties of the grafted catalysts after activation with Al₂Et₃Cl₃ are compared with the homogeneous equivalent system in propylene oligomerization. The identification of dimers leads to the determination of preferential reaction steps and the corresponding active species. Differences of the insertion modes of propylene are correlated to the textural properties of the support. Supporting the nickel active species reduces the isomerization side reactions and changes the mode of insertion of the first olefin.     

铜系催化剂选择性催化还原脱除NOx研究

以硅胶改性堇青石蜂窝陶瓷为载体,分别制备了以Cu-O、Cu-Ce-O和Cu-Ce-Mn-O为活性组分的催化剂。以CO(NH₂)₂为还原剂,在固定床反应器中进行选择性催化还原NO的研究。采用XRD、SEM和BET等测试方法对催化剂进行表征。结果表明,在温度(300～500) ℃,催化剂Cu-Ce-Mn-O/SiO₂/堇青石的活性优于催化剂Cu-O/SiO₂/堇青石和Cu-Ce-O/SiO₂/堇青石,反应温度为450 ℃、空速为8 000 h^-1时,Cu-Ce-Mn-O/SiO₂/堇青石催化剂催化还原NO的转化率可达到88%。     

Preparation, evaluation and characterization of copper catalysts for ethanol fuelled diesel engines

Copper-based monolithic honeycomb catalysts for ethanol fuelled diesel engines have been prepared and evaluated. The washcoat consisted either of alumina or titania. Two different methods to apply the active material were used; incipient wetness impregnation and deposition precipitation. The catalysts have been evaluated in a laboratory reactor and have been characterised using SEM, XRPD, TEM, TPR, XPS, BET surface area and pore-size distribution measurements. Both the choice of washcoat material as well as the preparation method is of importance. Titania as washcoat gave a better performing catalyst than alumina in this case. Deposition precipitation gave a better catalyst than incipient wetness impregnation when alumina was used as washcoat, as well as at low temperatures for titania catalysts.     

4,4′BOX based catalysts: Synthesis,structure and catalytic application

The synthesis of two new 4,4′ bisoxazoline ligands is described. The use of copper complexes of these and three other recently described related ligands as catalysts in a cyclopropanation reaction is discussed. The first structural data on one such chiral copper complex is reported herein.     

Synthesis and catalytic properties of eggshell cobalt catalysts for the Fischer-Tropsch synthesis

CO diffusional restrictions decrease C₅₊ synthesis rates and selectivity within large (1–3 mm) catalyst pellets often required in Fischer-Tropsch (FT) synthesis reactors. Eggshell catalysts, where Co is located preferentially near outer pellet surfaces, reduce the severity of these transport restrictions and lead to higher synthesis rates and C₅₊ selectivity. Maximum C₅₊ selectivities occur on catalysts with intermediate shell thickness, within which transport restrictions limit the removal of reactive olefins but not the arrival of reactants at catalytic sites. A new synthetic technique leads to sharp distributions of active sites near outer pellet surfaces by controlling the rate of imbibition of cobalt nitrate melts. Also, slow reduction of the impregnated salt leads to moderate Co dispersions (0.05–0.10) even at high local Co loadings present within shell regions.     

负载型铬基催化材料的制备与应用

负载型铬基催化材料不仅可显著提高铬活性组分的分散度并保留其多价态性,同时兼具多孔载体材料固有的孔结构、强酸性及优异的分子扩散性能,从而表现出良好的催化活性,并作为一类重要的催化剂有效应用于多种催化过程。本文详细阐述了目前负载型铬基催化剂在制备方法及催化应用方面的研究进展,并就合成方法、载体性质、金属前体及助剂等因素对铬物种引入量、分散程度及配位状态的影响以及进而造成对催化剂孔道结构、反应活性及使用寿命的影响进行了详尽地评述。同时指出了通过改变载体的表面酸性、孔结构及其与活性组分铬物种间的相互作用,从而提高铬物种在载体中的分散度和稳定性是今后负载型铬基催化材料研究的重要方向。