Kinetics of the liquid-phase oxidation of cyclooctene in the presence of MnO2

The kinetics of the liquid-phase oxidation of cyclooctene by molecular oxygen in the presence of a MnC₂ catalyst is studied. It is found that MnC₂ is an initiator of this reaction and has no effect on the steps of chain propagation and termination. The oxidation occurs by a radical chain mechanism with the escape of radicals to the bulk of the reaction mixture. Radicals are formed by the interaction of the olefin with the solid catalyst surface. The kinetic parameters of the reaction are calculated.     

Side Reactions in the Liquid-Phase Cyclohexanone Ammoximation

Influence of metal ions on hydrogen peroxide decomposition on the liquid-phase ammoximation of cyclohexanone was studied in homogeneous and heterogeneous (over titanium silicalite) conditions. The latter reaction is accompanied by side reactions, which deactivate the catalyst. Deactivation behavior is discussed.     

Catalytic hydrodechlorination on palladium-containing catalysts

The catalytic liquid-phase hydrodechlorination of chlorobenzene on supported palladium-containing catalysts has been investigated. The following processes capable of deactivating the catalyst occur during the liquid-phase hydrodechlorination: the coarsening of supported metal particles, the washoff of the active component with the reaction medium, and potassium chloride deposition on the catalyst surface. The effects of the active component composition and of the preparation method on the hydrodechlorination activity and deactivation stability of the catalysts have been studied. The catalysts have been characterized by several physical methods.     

负载离子液体纳米钯催化芳卤羰化反应

研究了高分散性的负载离子液体纳米钯催化剂的制备及其催化芳卤羰化反应的性能. 用XRD、HRTEM和XPS等方法对催化剂进行了表征, 结果表明, 钯组分处于高分散零价态, 其平均粒径小于5 nm, 且催化剂表面存在一厚度适中的离子液体液膜, 有利于提高催化剂的稳定性; 该催化剂对PhI、PhBr、PhCl的羰化反应的催化活性优于离子液体两相催化体系, 在优化的反应条件下, 碘苯的转化率可达99.3％, 生成苯甲酸乙酯的转化频率(TOF)可高达4926 h−1, 反应产物中苯甲酸乙酯的选择性大于99％.     

完全液相法制备的Cu-Zn-Si-Al浆状催化剂一步法合成二甲醚的失活研究

采用完全液相法制备了Cu-Zn-Si-Al浆状二甲醚合成催化剂, 分析研究了其在浆态床合成气一步法合成二甲醚过程中的失活现象和机理. 采用X射线粉末衍射、 N_2吸附测试、 X射线光电子能谱以及元素分析等表征方法对催化剂使用前后的变化情况进行了分析. 结果表明, 完全液相法制备的Cu-Zn-Si-Al浆状催化剂的失活与传统方法制备的催化剂不尽相同, 没有发现催化剂Cu晶粒的长大和比表面积降低等失活因素;催化剂失活与Si的存在有关, Cu组分的流失是其失活的主要原因.     

The influence of the nature of substituents on adsorbability and the rate of liquid-phase hydrogenation of nitrobenzenes

The influence of the nature of substituents on the rate of liquid-phase hydrogenation of nitrobenzenes on Raney nickel was studied in an aqueous solution of 2-propanol. Interrelation between the rate of the reaction on the equiaccessible surface of the catalyst and solvation parameters, reactivity indices, and adsorption values of hydrogenated compounds containing electron acceptor (4-nitrobenzoic acid) and electron donor (4-nitroaniline) substituents was considered.     

Liquid-Phase Hydrogenation of Acetylene to Ethylene in a Flow on Pd/Al2O3 and Pd-Ga/Al2O3 Catalysts in the Presence of CO

Catalytic properties of Pd/Al₂O₃ and Pd-Ga/Al₂O₃ in selective liquid-phase hydrogenation of acetylene in a flow under pressure and the effect exerted on them by introduction of CO into the feed were studied. The presence of CO in the reaction mixture ensures the reaction with the predominant formation of ethylene. Introduction of gallium into the catalyst formulation prevents the catalyst deactivation. Simultaneous action of these factors allows reaching high yield of the target product in combination with long operation life of the catalyst.

     

完全液相法与溶胶-凝胶法制备Cu-Zn-Al双功能催化剂对浆态床一步法合成二甲醚的催化性能比较

采用完全液相法和溶胶-凝胶法分别制备了组成完全相同的Cu-Zn-Al双功能催化剂,用XRD、氮气吸附-脱附实验和XPS等手段对催化剂的性质进行表征,考察了催化剂对浆态床一步法合成二甲醚反应的催化性能.结果表明,两种方法制备的Cu基催化剂中Cu组分的物相和表面Cu含量明显不同,而催化剂的织构性质基本相同.完全液相法制备的...     

Efficient combination of task-specific ionic liquid and microwave dielectric heating applied to one-pot three component synthesis of a small library of 4-thiazolidinones

The first report of the use of task-specific ionic liquid as synthetic equivalent of ionic liquid-phase matrice for the preparation of a small library of 4-thiazolidinones is reported in this paper. The starting (ethyleneglycol)ionic liquid-phase is functionalized in good yields with 4-(formylphenoxy)butyric acid by using usual esterification reaction conditions (DCC/DMAP as catalyst). The synthesis of the ionic liquid-phase bound 4-thiazolidinones was performed by a one-pot three-component condensation under microwave dielectric heating. The final cleavage under microwave/catalysis strategy provides the expected 4-thiazolidinones in high purity after flash-chromatography purification. According to the ionic liquid-phase organic synthesis (IoLiPOS) methodology, it was found that optimized reaction conditions were performed by standard analytical methods (NMR, TLC). The ¹H, ¹³C NMR spectrum of some representative 4-thiazolidinones and ionic liquid-phase bound benzaldehyde are also reported.     

Methanol dehydrogenation in the liquid phase with Ru/active carbon catalyst

In contrast to the gas-phase reaction, the liquid-phase reaction of methanol with Ru/C catalyst scarcely gave methane. Product distribution strongly depended on reaction conditions even under atmospheric pressure.     

浆态床二甲醚合成催化剂失活因素研究

以完全液相法制备的Si-Al基二甲醚合成催化剂为研究对象,运用XRD、TEM、XPS以及XRF等方法对失活催化剂的表面结构和性质进行表征,并与传统催化剂进行对比,探讨影响催化剂寿命的本质原因。研究结果表明,传统复合催化剂失活的主要原因是反应过程中Cu组分的烧结、团聚以及催化剂比表面积降低等;而Si-Al基完全液相法催化剂失活是由于Cu组分流失所致。     

Catalytic and kinetic study of the liquid-phase hydrogenation of various organic substrates over a polymer-anchored Pd(II) catalyst

A polymer-anchored Pd(II) complex has been prepared and characterized using scanning electron microscopy, elemental analysis, atomic absorption spectroscopy and FTIR. The catalyst shows excellent catalytic activity in the liquid-phase hydrogenation of substituted nitrobenzenes at normal pressure of hydrogen gas at 25 °C in DMF medium. We have also studied the liquid-phase hydrogenation of other organic substrates such as alkenes, alkynes, aromatic aldehydes, etc. The influences of various parameters such as amount of catalyst, concentration of substrate, temperature and solvent have been studied. The catalyst can be used five times without much loss in activity.     

纳米TiO2-SnO2介孔材料的制备及其对含氰废水的光催化降解性能

以TiCl4和SnCl4为原料,采用直接水解常压液相反应合成出了纳米TiO2-SnO2复合介孔材料.利用XRD和TEM及漫反射谱等对样品进行了表征,并研究了纳米TiO2-SnO2复合介孔材料对含氰废水的光催化降解性能.结果表明,纳米TiO2与SnO2复合后,导致材料的光谱响应拓宽;此种催化剂在日光灯下比在紫外灯下对废水中CN-的降解效果要好.     

NMR imaging of the distribution of the liquid phase in a catalyst pellet during alpha-methylstyrene evaporation accompanied by its vapor-phase hydrogenation

This communication reports the first application of NMR imaging to study the progress of a multiphase heterogeneous catalytic reaction in situ. Various stationary regimes of alpha-methylstyrene (AMS) hydrogenation on a single Pt/gamma-Al2O3 catalyst pellet have been investigated. The two-dimensional maps of the liquid-phase distribution within the pellet have been obtained in the course of the catalytic reaction, with the pellet temperature rising up to 185 degrees C. The large liquid-phase concentration gradients have been shown to exist under conditions of liquid AMS evaporation accompanied by its vapor-phase hydrogenation. It has been demonstrated that despite a substantial broadening of the NMR lines of liquids permeating porous solids the quantification of the relative amounts of AMS and the major reaction product cumene with spatial resolution across the pellet is feasible.     

Controlled deactivation of a skeletal nickel catalyst with sodium silfide in liquid-phase hydrogenation reactions

The kinetics of the liquid-phase hydrogenation of sodium maleate on skeletal nickel catalysts subjected to controlled deactivation with sodium sulfide solutions was studied. The possibility of reactivating partially deactivated skeletal nickel was systematically studied for the first time, and it was found that its activity in liquid-phase hydrogenation reactions can be regulated by the introduction of a catalyst poison in small amounts into the system.     

利用乙醇重整制氢进行硝基苯原位液相加氢合成苯胺

 利用乙醇液相催化重整制得的氢直接进行硝基苯原位液相加氢合成苯胺. 考察了不同催化剂、反应温度及反应时间等因素的影响. 在以Pt/Al2O3为催化剂,反应温度220 ℃和反应时间3 h的条件下,硝基苯的转化率可达99.3%, 苯胺的选择性为99.8%, 催化剂表现出较高的加氢活性和选择性.     

Liquid-Phase Oxidation of Inorganic Sulfides in Aqueous Medium in the Presence of a Catalyst Based on 3,3′,5,5′-Tetra-<Emphasis Type="Italic">tert</Emphasis>-Butyl-4,4′-Stilbenequinone

The kinetics of liquid-phase oxidation by oxygen from sodium sulfide was studied in an aqueous medium in the presence of a catalyst based on 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone dissolved in kerosene fraction. It was found that 3,3′,5,5′-tetra-tert-butyl-4,4′-stilbenequinone selectively oxidizes sodium sulfide to sodium thiosulfate. The reaction orders in sodium sulfide, oxygen, and the catalyst were determined. The reaction mechanism was proposed.     

氧化硅掺杂对硫酸化氧化锆酸性中心浓度和强度的提高

用氧化硅掺杂硫酸化氧化锆可以增强硫酸化氧化锆的酸性. 以413～453 K下甲醇液相脱水为模型反应考察了改进催化剂的性能. 结果表明,在掺杂和未掺杂氧化硅的硫酸化氧化锆催化剂上甲醇均相继脱水生成二甲醚和乙烯. 在掺杂了氧化硅的催化剂上还有一定量的丙烯生成,而未掺杂氧化硅的催化剂上则没有丙烯生成.     

Controlled Preparation of Hydrangea-like 0.3Zn-0.15Sn/CuO Catalysts for the Rochow-Müller Reaction by Microwave-Assisted Liquid-Phase Synergistic Impregnation

In catalytic reactions, trace amounts of promoters can make up for the low activity of a catalyst and significantly affect the physicochemical properties of the catalyst. Exploring a simple and efficient composite Cu-based catalyst is essential to the Rochow-Müller reaction. In this work, monodisperse, a hydrangea-like 0.3Zn-0.15Sn/CuO composite catalyst in the Rochow-Müller reaction. The composite was synthesized via a microwave-assisted liquid-phase synergistic impregnation method in which Sn and Zn were used to dope the CuO surface to create strong Si interaction points. A significant increase in the catalytic activity of CuO was observed after Sn and Zn doping, attributed to the rearrangement of charges on the CuO surface and increase in the Cu atom's core electron density. This work provided a novel and efficient method for preparing efficient Cu-based catalysts for the Rochow-Müller reaction.     

加料方式及底物浓度对Ti-MWW催化剂上环己酮氨肟化反应的影响

 研究了加料方式和底物浓度对钛硅分子筛Ti-MWW催化环己酮液相氨肟化反应的影响. 结果表明,加料方式对 Ti-MWW 催化环己酮氨肟化过程有重要影响,过氧化氢的浓度对反应过程也有一定的影响. 在过氧化氢缓慢加入反应体系的情况下,环己酮转化率和环己酮肟选择性都高于99%, 而且该反应过程以水作溶剂,对环境友好.