Silica Functionalized Magnetic Nickel Ferrite Nanoparticles as an Efficient Recyclable Catalyst for S-Arylation in Aqueous Medium

Silica coated NiFe₂O₄ NPs has been synthesized. It has been characterized by XRD, TEM, SEM-EDX and FT-IR. The catalytic activity of the Silica coated NiFe₂O₄ NPs has been tested for the S-arylation reaction in water with high yield. In this reaction water was used as the green solvent. The effects of solvents, reaction time and catalyst amount for the reaction was reported. This catalyst showed excellent catalytic activity and recyclability. The Silica coated NiFe₂O₄ NPs catalyst could be easily recovered by filtration and reused more than five times without appreciable loss of its initial activity.     

Ruthenium Phenylindenyl Complex as an Efficient Transfer Hydrogenation Catalyst

An efficient and green protocol for the transfer hydrogenation of carbonyl and imine compounds is presented. The transformations are catalysed by the inexpensive and easily synthesised complex [RuCl(PPh₃)(3‐phenylindenyl)]. Its catalytic activity was compared to that of the most commonly encountered ruthenium complexes in transfer hydrogenation reactions involving several protypical substrates.     

Amino-functionalized Ionic Liquid as an Efficient and Recyclable Catalyst for Knoevenagel Reactions in Water

The Knoevenagel condensation of aromatic aldehydes with malononitrile and ethyl cyanoacetate using amino-functionalized ionic liquid, 1-aminoethyl-3-methylimidazolium hexafluorophosphate as catalyst was successfully performed in aqueous media. The catalyst can be recycled and reused at least six times without apparently loss of activity.      

负载Cu-Co纳米氧化物高效催化氧化水合肼研究

催化湿式过氧化氢技术(CWPO)以廉价易得的H2O2作为氧化剂,不仅可以使反应在常温常压下进行,而且H2O2分解产生的羟基自由基OH·具有很强的氧化能力,能氧化绝大多数有机物,且氧化速度较快,是处理难降解物质的重要方法之一。催化剂是催化湿式过氧化氢技术的关键,研究和开发新型高效稳定的催化剂,对于催化湿式过氧化氢技术在废水处理领域的推广应用更是至关重要。本文以肼废水为处理对象,探讨了负载型催化剂在CWPO工艺中对肼废水的催化降解活性。采用浸渍法分别制备Cu O-γ/Al2O3催化剂和钴改性Cu O-Co3O4-γ/Al2O3催化剂在CWPO工艺中对高COD的肼废水的催化降解活性进行对比。相较于Cu O-γ/Al2O3,含Co的催化剂在催化降解水合肼废水上具有更高的催化活性和稳定性。在反应温度60℃,起始p H=8.0,3 m L/L的H2O2的条件下,5%Cu O-0.5%Co3O4-γ/Al2O3催化剂催化降解40 min后COD的去除率达到91.5%。该纳米催化剂能够广泛运用于环境污染物处理上。     

Single Electron Transfer Reactions of Perfluoroalkyl Iodides

Perfluoroalkyl iodides react with alkenes, alkynes, and nucleophiles in the presence of metals, transition metal complexes, oxidants, or under UV irradiation. A single electron transfer mechanism is proposed and discussed.     

Electron Transfer Reactions in Biological Nitrogen Fixation

In this review, we summarize our recent efforts toward understanding electron transfer (ET) processes in nitrogenase, the only enzyme capable of reducing dinitrogen to ammonia. We discuss new structural and biochemical perspectives on the role of ATP-dependent interactions between the two components of nitrogenase, Fe-protein (FeP) and MoFe-protein (MoFeP), and how these interactions may regulate interprotein ET and catalysis. We also discuss the implications of our work on FeP- and ATP-independent, photoredox-activated substrate reduction by MoFeP. Elucidating why and how ATP-hydrolysis is needed to control electron and proton flow in nitrogenase is not only a fundamentally important question in biological redox chemistry and energy transduction, but it also holds the key to understanding the intimate mechanism of dinitrogen reduction.     

金催化的吲哚对α-氨基酮的Friedel-Crafts烷基化反应

以金作为催化剂高效地实现了吲哚对α-氨基酮的Friedel-Crafts烷基化反应。反应适用范围广泛,各种取代的α-氨基酮与吲哚高产率的生成相应的化合物,底物α-氨基酮分子中苯环上取代基的电负性对反应速度及产率没有明显影响。该方法具有反应时间短、产率高、适用范围广泛、后处理方便等优点,扩展了金催化剂在有机反应中的应用。     

Hafnium Triflate as an Efficient Catalyst for Direct Friedel–Crafts Reactions of Chromene Hemiacetals

The direct Friedel–Crafts reaction of chromene hemiacetals with indoles, furans and sterically hindered anilines has been accomplished with high selectivity and excellent yields in the presence of a catalytic amount of hafnium triflate [Hf(OTf)₄, 0.1 mol%, 0–40 °C]. The mild conditions tolerate various sensitive functional and protecting groups, and the products were confirmed unambiguously from their spectra and by single‐crystal X‐ray analysis. This direct Friedel–Crafts reaction of chromene hemiacetals should inspire and encourage the consideration of hafnium triflate in the development of mild reaction conditions for the efficient derivatization of hemiacetal‐containing compounds.     

Quasicrystalline Structures as Catalyst Precursors for Hydrogenation Reactions

The quasicrystalline structures of alloys with nominal compositions of Al₇₂Ni_13.4Co_14.6 and Al_72.3Ni_7.8Co_19.8 were characterized by X-ray diffraction, transmission electron microscopy and scanning electron microscopy. For catalytic application, the solids were leached with an alkaline NaOH solution and tested at 373 K with two model reactions under atmospheric pressure: hydrogenation of crotonaldehyde and acetonitrile. The catalytic activities of these leached alloys were compared to that of a Raney nickel reference catalyst. Catalysts prepared from quasicrystals showed high catalytic activities and high selectivities towards butanal (in crotonaldehyde hydrogenation) and ethylamine (in acetonitrile hydrogenation).     

Ru Nanoparticles on Pr2O3 as an Efficient Catalyst for Hydrogen Production from Ammonia Decomposition

Catalysis Letters - Development of efficient catalysts for ammonia decomposition is crucial for hydrogen production from ammonia. Herein, Ru nanoparticles (NPs) highly dispersed on Pr2O3 (Ru/Pr2O3)...     

Selective Aerobic Oxidation of Alcohols by Using Manganese Oxide Nanoparticles as an Efficient Heterogeneous Catalyst

Manganese oxide (Mn₃O₄) nanoparticles have been successfully innovated to be efficient catalysts not only for the aerobic oxidation of various alcohols to aldehydes or ketones, but also for the selective aerobic oxidation of mixed alcohols.     

Proline‐Functionalized Magnetic Core‐Shell Nanoparticles as Efficient and Recyclable Organocatalysts for Aldol Reactions

Novel magnetically tagged organocatalysts have been developed based on core‐shell nanoparticles consisting of magnetite cores and polyacrylate shells containing 4‐hydroxyproline moieties. These catalysts allow the performance of direct asymmetric aldol reactions of aromatic aldehydes with ketones in the presence of benzoic acid providing high yields and ees. Straightforward magnetic separation and recycling of a catalyst for up to 9 runs is possible without a significant loss of efficiency.     

CdTe纳米颗粒的制备及与GSH电子转移机制研究

以CdCl₂·2.5H₂O为镉源,TeO₂为碲源,水合肼为还原剂,利用共沉淀-还原法制备了CdTe纳米颗粒。采用扫描电镜、X射线衍射仪、激光拉曼光谱仪、傅里叶红外光谱仪和固体紫外-可见分光光度计对CdTe纳米颗粒的形貌、结构和光吸收性能进行表征。结果表明,水浴温度为80 ℃、水浴时间为6 h、烧结温度为400 ℃、烧结时间为2 h时制备的CdTe有较高的结晶度和较好的光吸收性。通过荧光光谱测试发现,CdTe溶液的荧光强度随谷胱甘肽(GSH)浓度的增加而增大,在0.005~0.8 mmol/L检测范围的检测极限(LOD)为0.004 mmol/L。该研究为制备CdTe荧光探测器提供了新技术,而且为解释GSH在CdTe溶液中的荧光响应提供了依据。     

Glycerol as An Efficient Promoting Medium for Organic Reactions

Whereas the beneficial effect of water on reaction rate is decreased with an increase of the reactant′s hydrophobicity, we report here that the use of glycerol as solvent was able to considerably accelerate the reaction rate of an organic reaction even starting from more hydrophobic substrates than those usually used on water. Moreover, the possibility of directly using crude glycerol generated by the biodiesel industry economically and environmentally improves the interest of using glycerol as solvent.     

Mathematical Modeling of Heat and Mass Transfer in the Drying of Granules Used as a Support for a Nickel Catalyst

Theoretical Foundations of Chemical Engineering - The results of studying the convective drying of cylindrical granules of a support for a nickel catalyst using mathematical modeling techniques...     

An Efficient Protocol for Aza-Michael Addition Reactions Under Solvent-Free Condition Employing Sulfated Zirconia Catalyst

The aza-Michael addition reactions of amines with α,β-unsaturated carbonyl compounds were efficiently carried out at room temperature under solvent-free condition employing sulfated zirconia as a reusable heterogeneous catalyst. The desired products were formed in short reaction times and in high yields. The bulk and surface properties of the synthesized catalyst was examined by X-ray powder diffraction, BET surface area, temperature programmed desorption of ammonia, scanning electron microscopy and thermogravimetric techniques. Characterization results reveal the super acidic nature of the catalyst.     

从废镍催化剂中提取镍,生产硫酸镍

介绍了如何从废镍催化剂中提取镍,减少环境污染,降低硫酸镍的制造成本。