PRODUCTION OF LIGHT OLEFINS FROM CO2 HYDROGENATION OVER Fe/SILICALITE-2 CATALYST IV. PERFORMANCE OF THE K-Fe-MnO/Si-2 CATALYST

A new K-Fe-MnO/Si-2 catalyst has been developed for CO2 hydrogenation, which exhibits a fascinating reaction activity and light olefin selectivity for CO2 hydrogenation. Over the catalyst, it is observed that olefin selectivity increases apparently with reaction temperature and/or GHSV, while decreases when reaction pressure is up. Furthermore, the catalyst exhibits a better stability for CO2 hydrogenation. However, coke deposited on catalyst surface is formed at the beginning of the reaction period and then reached a stable state during CO2 hydrogenation. Generally, the K-Fe-MnO/Si-2 catalyst can be regenerated for CO2 hydrogenation, the same selectivity of C2=-C4=alkenes is regained without any decrease in catalyst activity with time on stream.     

PEGylation of an artificial O2 and CO receptor: synthesis, characterisation and pharmacokinetic study

A synthetic oxygen (O(2)) and carbon monoxide (CO) receptor (hemoCD) composed of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphinatoiron(ii) and a per-O-methylated β-cyclodextrin dimer with a pyridine linker (Py3CD) was functionalised with poly(ethylene glycol) (PEG) to elongate the circulation time of the receptor in the bloodstream. α-PEG monocarboxylic acid (HOOC(CH(2))(3)(CO)O-PEG(mw)-OCH(3); mw = 750 or 5k) or α,ω-PEG dicarboxylic acid (HOOC(CH(2))(3)(CO)O-PEG(mw)-O(CO)(CH(2))(3)COOH; mw = 10k or 20k) was reacted with the amino group of 5-(4-aminophenyl)-10,15,20-tris(4-sulfonatophenyl)porphyrin to afford a porphyrin monomer having a PEG chain or a porphyrin dimer having a PEG linker, respectively. The ferrous complexes of these PEGylated porphyrins (PEG750-, PEG5k-, PEG10k- and PEG20k-hemoCDs) bound O(2) in aqueous solution, P(1/2) values being 6.5-8.1 Torr at pH 7.0 and 25 °C. Each PEG(mw)-hemoCD was infused into the femoral vein of a Wistar male rat. After 6 h of the infusions, 67, 82, 86 and 42% of PEG750-, PEG5k-, PEG10k- and PEG20k-hemoCD were excreted in the urine. PEG750-hemoCD with a hydrodynamic diameter (D(h)) of 3.4 nm seemed to partly leak from the blood vessels (pore size: 2-6 nm) before renal filtration (pore size: 4-14 nm). PEG5k- (D(h) = 6.2 nm) and PEG10k-hemoCDs (9.0 nm) hardly passed through the blood vessels but were fully filtered by the kidney, resulting in high excretion rates. A considerable amount of PEG20k-hemoCD (D(h) = 12.0 nm) was retained in the blood even at 6 h after administration. The present study demonstrates that the behaviour of hemoCD in blood after administration can be controlled by modification of hemoCD with PEG having an appropriate molecular weight.     

PRODUCTION OF LIGHT OLEFINS FROM CO_2 HYDROGENATION OVER Fe/SILICALITE-2 CATALYST Ⅳ. PERFORMANCE OF THE K-Fe-Mno/Si-2 CATALYST

IntroductionInordertodevelopanewcatalystwithbCttercarelyticedivityforseleCtiveproductionoflightolefinsfromCOZhydrogenation,asilicalite-2(St-2)zeolitesupportedFecatalystpromotedbyalkalimetalandMnOadditiveshasbeenacquiredwithmorethan68%oflightolefinselectiv…     

低镍催化剂上CO和CO_2加氢反应的对比研究

采用ＣＯ和ＣＯ＿２对比加氢活性测试，ＸＲＤ及ＴＰＲ方法研究了两个不同Ｎａ助剂含量的低镍Ｎｉ／Ａｌ＿２Ｏ＿３体系的性能。实验发现，在低镍催化剂上ＣＯ＿２在较低温度下就可加氢生成甲烷，而ＣＯ则需要更高的温度，ＣＯ＿２无需先经逆变换生成ＣＯ，然后再加氢，它可直接加氢生成ＣＨ＿４。在同一催化剂上，ＣＯ＿２加氢生成ＣＨ＿４的表现活化能要低于ＣＯ加氢生成ＣＨ＿４反应的表现活化能。晶相ＮｉＯ还原后形成的活性相对ＣＯ＿２加氢反应的活性明显高于它对ＣＯ的加氢活性，非晶相镍氧化物还原后形成的活性相对ＣＯ的加氢反应特别有利。Ｎａ助剂的含量不同会造成Ｎｉ氧化物物种的分配不同，从而导致ＣＯ、ＣＯ＿２的加氢活性及其随温度的变化也不相同，催化剂对ＣＯ、ＣＯ＿２加氢反应作用的本质是不相同的。     

CO在YBa2Cu3Ox薄膜上吸附与加氢的研究

ＹＢａ２Ｃｕ３Ｏｘ（ｘ＝６－７）薄膜被合成在ＹＳＺ基底上，用ＦＴＩＲ，ＸＰＳ，ＸＲＤ等手段原位研究ＣＯ在薄膜上的吸附及加氢行为。ＣＯ吸附在Ｃｕ位置上，与ＹＢＣＯ体相中的Ｏ作用，生成表面ＣＯ２或－ＣＯＯ基团，导致ＹＢＣＯ中生产氧空位，使ＹＢＣＯ发生昌型转变，Ｃｕ＾２＋被还原为Ｃｕ＾＋或Ｃｕ＾０．ＹＢＣＯ中的氧空位有利于ＣＯ、ＣＯ２及Ｈ２的吸附。ＣＯ、ＣＯ２在ＹＢＣＯ膜上的加氢产物为ＣＨ３ＯＨ、ＣＨ３     

Swelled plastics in supercritical CO2 as media for stabilization of metal nanoparticles and for catalytic hydrogenation

Swelled plastics in supercritical carbon dioxide provide unique environments for stabilizing palladium and rhodium nanoparticles and for catalytic hydrogenation. Complete hydrogenation of benzene to cyclohexane can be achieved in 10 minutes using the plastic stabilized Rh nanoparticles at 50 degrees C in supercritical CO(2). High efficiency, reusability, and rapid separation of products are some advantages of the plastic stabilized metal nanoparticles for catalytic hydrogenation in supercritical CO(2).     

PRODUCTION OF LIGHT ALKENES FROM CO AND/OR CO_2 HYDROGENATION OVER K-Fe-MnO/SILICALITE-2 CATALYST

High selectivity to light alkenes can be achieved from CO and CO_2hydrogenation over K-Fe-MnO/Si-2 catalyst.The alkene selectivity isinsensitive to reaction temperature for CO hydrogenation,while apparentlyincreases for CO_2 hydrogenation with raising reaction temperature.An increasein alkene selectivity is observed for both CO and CO_2 hydrogenation with GHSVrising,While a decrease with the elevation of reaction pressure for both CO/H_2and CO_2/H_2 reaction.A two-step mechanism is suggested forCO_2 hydrogenation to form hydrocarbons,by which the variations incontributions of CO and HC as products of CO_2/H_2 reaction with change ofreaction temperature,GHSV and pressure are explained.Moreover,thecatalyst is favorable for selective production of light olefins,which can alsoconcern the slightly secondary reactions of light olefins to some extent.     

超细Cu-ZnO-ZrO2催化剂上甲醇合成的TPSR和TPD研究

采用ＭＳ－ＴＰＳＲ和ＭＳ－ＴＰＤ技术在不同粒度的超细Ｃｕ－ＺｎＯ－ＺｒＯ２催化上考查了ＣＯ２和ＣＯ加氢合成甲醇的反应过程和吸附活化特征。研究表明,ＣＯ２和ＣＯ都可以直接加氢合成甲醇。     

Reaction development and mechanistic study of a ruthenium catalyzed intramolecular asymmetric reductive amination en route to the dual Orexin inhibitor Suvorexant (MK-4305)

The first example of an intramolecular asymmetric reductive amination of a dialkyl ketone with an aliphatic amine has been developed for the synthesis of Suvorexant (MK-4305), a potent dual Orexin antagonist under development for the treatment of sleep disorders. This challenging transformation is mediated by a novel Ru-based transfer hydrogenation catalyst that provides the desired diazepane ring in 97% yield and 94.5% ee. Mechanistic studies have revealed that CO(2), produced as a necessary byproduct of this transfer hydrogenation reaction, has pronounced effects on the efficiency of the Ru catalyst, the form of the amine product, and the kinetics of the transformation. A simple kinetic model explains how product inhibition by CO(2) leads to overall first-order kinetics, but yields an apparent zero-order dependence on initial substrate concentration. The deleterious effects of CO(2) on reaction rates and product isolation can be overcome by purging CO(2) from the system. Moreover, the rate of ketone hydrogenation can be greatly accelerated by purging of CO(2) or trapping with nucleophilic secondary amines.     

载体表面性质对Cu/ZrO2催化剂CO加氢反应行为的影响

用XRD、LRS、NH₃-TPD、CO₂-TPD和CO-FTIR等表征手段考察了不同温度焙烧的氧化锆表面性质的差别,特别是表面酸碱性的差异对Cu/ZrO₂催化剂CO加氢反应行为的影响。结果表明,不同温度焙烧的氧化锆表面酸碱性具有较大的差异,其中以450℃焙烧的氧化锆具有较高的表面碱性和最低酸性。这些表面性质的差异对于Cu/ZrO₂催化剂的CO吸附行为产生较大的影响,进而影响CO的加氢反应活性。以450℃焙烧的氧化锆为载体时,Cu/ZrO₂催化剂具有较好的反应活性。     

Porous TiO(2)/SiO(2) composite prepared using PEG as template direction reagent with assistance of supercritical CO(2)

Titania-silica mesoporous composites have been prepared using polyethylene glycol (PEG) 20,000 as a template direction reagent with the assistance of supercritical carbon dioxide (SC CO(2)). For this preparation method, the composite precursors of tetrabutyl titanate (TBTT) and tetraethyl orthosilicate (TEOS) were dissolved in supercritical CO(2) and impregnated into PEG 20,000 using SC CO(2) as swelling agent and carrier. After removal of the PEG template by calcination in air at suitable temperatures, porous titania-silica composites were obtained. Effects of CO(2) pressure and temperature have been studied on the impregnation ratio during the supercritical fluid condition. The composite products were characterized by thermogravimetric analysis (TGA), X-ray diffraction (XRD), FTIR spectroscopy, nitrogen sorption-desorption experiments, scanning electronic microscope (SEM), and transmission electron microscope (TEM). XRD and nitrogen sorption-desorption experimental results indicate that the titania-silica composite crystallized in anatase phase and has a preferable BET surface area up to 301.98 m(2)/g. It was also demonstrated that the microstructure and macroproperty of TiO(2)/SiO(2) composites depend strongly on the experimental pressure during the impregnation process in SC CO(2). At suitable CO(2) pressure, silica even can be found in a single crystalline structure in nature by observation of TEM. At the same time, SEM indicates that the composite product existed in a spheric form or a cubic form inserted with many holes. So this work provides a new route to control and obtain the special micrography of TiO(2)/SiO(2) composites with the aid of suitable polymer templates in supercritical CO(2).     

Rh2CO2/Al2O3上H2吸附及CO和H2共吸附

CO加氢反应机理一直是许多化学工作者感兴趣的课题．Rh催化剂因其优良的性能而被用于 CO加氢机理研     

Continuous-Flow Hydrogenation of Carbon Dioxide to Pure Formic Acid using an Integrated scCO(2) Process with Immobilized Catalyst and Base

Dual role for CO(2) : Pure formic acid can be obtained continuously by hydrogenation of CO(2) in a single processing unit. An immobilized ruthenium organometallic catalyst and a nonvolatile base in an ionic liquid (IL) are combined with supercritical CO(2) as both reactant and extractive phase.     

在Cu-Zn-Al和Cu-Zn-Al-Li催化剂上CO/CO_2氢化制甲醇的研究(英文)

制备了Ｃｕ－Ｚｎ－Ａｌ （４／５０／５）催化剂（Ｃａｔ）和Ｃｕ－Ｚｎ－Ａｌ－Ｌｉ（４０／５０／５／５）催化剂（Ｃａｔ－Ｌｉ）．并将其分别用于由ＣＯ／Ｈ_２和ＣＯ_２／Ｈ_２合成甲醇。诸如ＴＰＤ、ＴＰＲ、ＴＰＳＲ、脉冲、ＣＤ３Ｉ－捕获、同位素标记、ＥＰＲ及原位ＤＲＩＦＴ等技术和方法被用来表征这两种催化剂及研究反应机理,对处于去氢、含氢及含氧态催化剂进行了对比研究以期阐明表面氧和表面氢对ＣＯ_２和ＣＯ活化所起的作用。提出了一个由甲酸根和甲醛氢化及甲醇氧化结果为证的ＣＯ／ＣＯ_２氢化机理。由于通过Ｌｉ 取代ＣｕＯ晶格上的Ｃｕ２＋形成的氢空位,在Ｃａｔ中添加Ｌｉ＋改善了甲醇合成活性。ＣＯ_２能被一捕获的电子（Ｆ-中心）活化,生成的ＣＯ2-能容易地被氢化成甲酸根和亚甲基双草酰,后者分解生成Ｈ２ＣＯ和表面氧。ＣＯ能被表面氧活化,生成的ＣＯ２－将遵循ＣＯ_２氢化的途径。在ＣＤ３Ｉ－捕获的实验中,我们捕获了表面氧。在无表面氧时,ＣＯ可能直接氢化成甲酸基,即ＣＯ_２氢化中的一途径。由亚甲基双草酰产生的Ｈ２ＣＯ表面模型可能与由甲醛吸附或ＣＯ氢化生成的Ｈ２ＣＯ表面模型不同。     

RhCo双金属催化剂的研究III. Rh+Co/Al2O3上表面羰基氢化物及其动态行为

利用连续流动微反研究了Rh+Co/Al2O3催化剂的CO加氢反应, 结果表明反应在220℃以上发生, 反应活性随着温度的升高和H2/CO值的增加而增加。利用TP-IR动态方法研究了Rh+Co/Al2O3上CO和H2共吸附及其动态行为。结果表明在Rh+Co/Al2O3的孪生及线式中心上, CO和H2室温共吸附时即有部分孪生及线式CO转化为相应的羰基氢化物, 随着温度的升高, 剩余的孪生和线式CO继续向相应的羰基氢化物转化。而羰基氢化物则向多羰基氢化物转化。在到达反应温度之前, 催化剂表面只存在羰基氢化物及相应的多氢羰基氢化物。在反应温度则导致产物CH4生成。与CO加氢反应和CO歧化的吸附态研究结果相关联, 作者认为Rh+Co/Al2O3上CO加氢生成CH4是经由羰基氢化物-多氢羰基氢化物途径。     

镍掺杂对Fe催化剂上CO_2加氢制烃影响的理论计算研究

为研究镍掺杂对铁基催化剂上二氧化碳加氢生成C_1和C_2烃类产物的影响,应用密度泛函理论进行了相关计算.在Fe(110)和Ni-Fe(110)表面上, CH~*物种是最有利的生成CH_4和C_2H_4的C_1物种(CH_x~*),其最可能的生成路径为CO_2→HCOO~*→HCO~*→CH~*.尽管CO_2直接解离为CO~*在动力学上相较于加氢生成HCOO~*和COOH~*是较为有利的,但CO~*进一步加氢生成HCO~*在能量上是不利的,其倾向于逆向解离回到CO~*. CH~*物种可以通过三步加氢反应生成CH_4或者经C—C耦合及两步加氢生成C_2H_4.在Fe(110)表面上,对甲烷和乙烯产物选择性起决定作用的基元反应能垒之间差异仅为0.10 eV,因此两者选择性相近.在将Ni原子引入Fe(110)表面后,生成甲烷与乙烯的选择性差异变大,导致乙烯的选择性提高.计算结果表明,添加少量金属Ni能够促进CO_2转化为CH~*,及两个CH~*物种发生C—C耦合和进一步加氢转化为乙烯.     

负载型Cu/Al2O3和Cu/ZnO催化剂上CO2加氢的原位FTIR及准原位XPS/HS-LEIS研究

铜基催化剂是工业合成甲醇中常用的催化剂,其主要包含Cu,ZnO,Al2O3三种组分,研究各组分在催化合成甲醇过程中的本质作用及其相互间的协同作用不仅是一个催化基础科学问题,同时对于设计和合成新型高性能的铜基催化剂也有重要指导作用.以往的研究主要针对Cu和ZnO二元组分,关于Al2O3的作用很少有报道,主要观点认为Al2...     

INFLUENCE OF VOCl_2-ADDITIVE IN Rh CATALYST ON CO HYDROGENATION

The influence of VOCl2 additive in the supported Rh catalysts derived from both Rh2 (CO )4 Cl2 and RhCl3 on CO hydrogenation was investigated. The VOCl2 additive as a promoter can effectively enhance the CO conversion and catalytic selectivity to ethanol. This effect is caused by the interaction of Rh with vanadium promoter. It is found that the Rh centers on which the gem- adsorbed CO could be formed are main active sites. The Rh2(CO)4Cl2 complex is better than the RhCl3 salt as the precursor of the Rh catalyst for the CO hydrogenation to ethanol.     

CO对CO2加氢合成甲醇的影响

甲醇是重要的有机化工原料，同时它也已被确认为尾气污染少、辛烷值高的汽、柴油接烧的洁净燃料和大功率燃料电池的燃料[1]．随着世界石油贮量的枯竭，甲醇汽车将快速发展，所以CO2加氢合成甲醇具有广阔的应用前景和深远的理论意义．铜基催化剂上CO2加氢主要存在二个竞争反应[2     

氧化铈对F-T反应铁锆催化剂的助催化作用

应用ＸＲＤ、ＸＰＳ、Ｍｏｓｓｂａｕｅｒ谱、ＴＰＲ、ＣＯ－ＴＰＤ、ＣＯ＋Ｈ２反应性能测量试等手段研究了ＣｅＯ２对Ｆ－Ｔ合成制低碳烯烃Ｃｅ－Ｆｅ／ＺｒＯ２催化剂催化性能的影响。结果表明，与Ｆｅ／Ｚｒ催化剂相比，加铈助剂后的催化剂Ｆ－Ｔ反应催化活性明显上升。