Gold Nanoparticles Supported on the Periodic Mesoporous Organosilicas as Efficient and Reusable Catalyst for Room Temperature Aerobic Oxidation of Alcohols

Gold nanoparticles supported on the channels of a bifunctional periodic mesoporous organosilica, were found to be a highly efficient catalyst system for the aerobic oxidation of various types of alcohols into their corresponding aldehydes and ketones at room temperature. The catalyst showed no significant loss of efficiency for the aerobic oxidation of benzyl alcohol to give benzaldehyde after 7 reaction cycles.     

Nanocrystalline Magnesium Oxide Stabilized Palladium(0): An Efficient Reusable Catalyst for Room Temperature Selective Aerobic Oxidation of Alcohols

Nanocrystalline magnesium oxide‐stabilized palladium(0) [NAP‐Mg‐Pd(0)], as an efficient catalytic system has been employed for the selective oxidation of alcohols using atmospheric oxygen as a green oxidant at room temperature. Various alcohols could be transformed into their corresponding aldehydes or ketones in good to excellent yields using a set of optimal conditions. NanoActive™ Magnesium Oxide Plus, [NAP‐MgO] with its three‐dimensional structure and well‐defined shape acts as an excellent support for well dispersed palladium(0) nanoparticles. This catalyst can be recovered and reused for several cycles without any significant loss of catalytic activity.     

Cu2O: a Simple and Efficient Reusable Catalyst for N-arylation of Nitrogen-containing Heterocycles with Aryl Halides

Cu₂O was found to be a simple and efficient catalyst for the N-arylation of a variety of nitrogen-containing heterocycles with aryl and heteroaryl chlorides, bromides and iodides to give the products in excellent yields. The catalyst can be recovered simply and reused for several times without significant loss of activity.     

Oxidative Aminocarbonylation of Terminal Alkynes for the Synthesis of Alk‐2‐ynamides by Using Palladium‐on‐Carbon as Efficient,Heterogeneous, Phosphine‐Free,and Reusable Catalyst

Palladium‐on‐carbon (Pd/C)‐catalyzed oxidative aminocarbonylations of alk‐1‐ynes with secondary amines provide the corresponding alk‐2‐ynamides in a good to excellent yields. This new methodology is applicable for the synthesis of a wide range of biologically active alk‐2‐ynamide derivatives. The developed protocol avoids the use of phosphine ligands, with an additional advantage of palladium catalyst recovery and reuse for up to four consecutive cycles.     

Magnetic CuFe2O4 Prepared by Polymeric Precursor Method as a Reusable Heterogeneous Fenton-like Catalyst for the Efficient Removal of Methylene Blue

The heterogeneous Fenton-like catalysts based on CuFe₂O₄ were prepared by polymeric precursor method at several annealing temperatures. The obtained catalysts were respectively characterized by X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, point of zero charge measurement, and vibrating sample magnetometer. The Fenton-like catalytic activity was evaluated via the oxidation of methylene blue with H₂O₂. The results show that the CuFe₂O₄ phase content and the particle size increase with the annealing temperatures whereas the surface OH groups and the surface acidity decrease. The prepared powders possess typical ferromagnetic properties which allow them to be easily recovered and reused. These catalysts also present highly catalytic activities for the oxidation of methylene blue, which is principally attributed to the catalysis of the CuFe₂O₄ phase. When the annealing temperature increased, the catalytic performance was reduced, corresponding to the increase of particle size and the decrease of surface OH groups.     

甘氨酸锌的室温固相合成及表征

以氯化锌和甘氨酸为原料,用一步室温固相反应合成了一水合甘氨酸锌,反应的较佳条件为:研磨时间80min,NaOH水溶液加入量0.4 mL,配位比1∶2.5,所得产物螯合率可达94.39%。通过红外光谱分析、热重-差热、XRD粉末衍射对产物进行了表征,证明产物的组成为Zn(gly)2.H2O。     

Scolecite as a Novel Heterogeneous Acid Catalyst for an Efficient Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Via Multi-component Biginelli Reaction

Scolecite is one kind of natural zeolite. A three component Biginelli reaction using scolecite as a novel heterogeneous acid catalyst is demonstrated. The short reaction time, clean reaction conditions, consistent yields and minimum environmental effects are important features of the reaction.     

Click Functionalization of Gold Nanoparticles Using the Very Efficient Catalyst Copper(I) (Hexabenzyl)tris(2‐aminoethyl)‐ amine Bromide

Whereas previous “click” functionalization (Huisgen‐type copper‐catalyzed alkyne‐azide cycloaddition, CuAAC) of various gold nanoparticles (AuNP) had systematically proven to be very difficult, tedious, providing low yields with the use of high amounts of copper sulfate+sodium ascorbate – the classic Sharpless catalyst, the new catalyst copper(I) (hexabenzyl)tris(2‐aminoethyl)amine bromide, {[Cu(I)(Hexabenzyl)Tren]Br} is shown here to be very efficient for the introduction of a large variety of organic, organometallic, dendronic and polymeric molecular fragments of various sizes, topologies and hydrophilicities. Indeed, 0.1–0.15 equiv. of this catalyst in toluene was used in each reaction under ambient conditions for 8 to 48 h with good yields without AuNP aggregation. The new functional AuNP have been characterized by ¹H NMR, IR and UV‐vis. (plasmon band) spectroscopy, cyclic voltammetry (CV), dynamic light scattering (DLS) and transmission electron microscopy (TEM).     

硫酸镓催化合成柠檬酸三（2-乙基己基）酯的研究

以柠檬酸和2-乙基己醇为原料,用硫酸镓为催化剂合成环保增塑剂柠檬酸三（2-乙基己基）酯,考察了反应温度、催化剂用量、醇酸摩尔比、催化剂重复使用次数等因素对反应结果的影响,对合成的产品进行了红外光谱分析。实验结果表明,硫酸镓具有催化活性高、易分离回收、重复使用性良好等优点。在最佳反应条件下,柠檬酸三（2-乙基）己酯收率在96％以上。     

An Extremely Active Pt/Carbon Nano-Tube Catalyst for Selective Oxidation of CO in H2 at Room Temperature

Pt catalyst supported on carbon nano-tube (CNT) was extremely active for the selective oxidation of CO in H₂ at room temperature, which was remarked contrast to the Pt supported on an active carbon (Vulcan carbon) and a graphite powder. Complete oxidation of CO was attained on a 5 wt.% Pt/CNT catalyst (0.8 g) at ca. 40 °C when the O₂/CO ratio in a flow of H₂ (20 mL/min) + CO (3.0 mL/min) + O₂ + N₂ was adjusted to be larger than 0.75 at the total flow rate of 100 mL/min. Specific activity of the Pt/CNT catalyst was explained by efficient provision of reactant molecules diffusing on CNT surface to Pt particles.     

Highly Efficient Room Temperature Synthesis of Silver‐Doped Zinc Oxide (ZnO:Ag) Nanoparticles: Structural,Optical, and Photocatalytic Properties

Synthesis of silver‐doped zinc oxide (ZnO:Ag) nanoparticles through precipitation method has been reported. The synthesis was conducted at room temperature and no subsequent thermal treatment was applied. ZnO nanoparticles were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), fourier transmission infrared spectroscopy (FTIR), and ultraviolet‐visible (UV–Vis) spectroscopy. Detailed crystallographic investigation was accomplished through Rietveld refinement. The effect of silver content on structural and optical properties of resultant ZnO nanoparticles has been reported. It was found that silver doping results in positional shifts for the XRD peaks and the absorption band edge of ZnO. These were attributed to the substitutional incorporation of Ag⁺ ions into Zn²⁺ sites within the ZnO crystal. In addition, higher silver incorporation resulted in smaller size for ZnO nanoparticles. The photocatalytic activity of the ZnO:Ag nanoparticles was also determined by methylene orange (MO) degradation studies and compared to that of undoped ZnO. Improved photocatalytic activity was obtained for ZnO:Ag nanoparticles. It has been shown that an optimum amount of silver dopant is required to obtain maximum photocatalytic activity.     

固体Ti(SO4)2催化合成苯甲酸甲酯

以固体Ti(SO4) 2 为催化剂、苯甲酸和甲醇为原料合成了苯甲酸甲酯。考察了催化剂用量、反应时间、醇酸比对酯产率的影响。实验结果表明 ,最佳实验条件为 :在 6 5～ 75℃下 ,催化剂用量为 8% (占苯甲酸质量分数 )、反应时间为 3h、甲醇与苯甲酸用量比为 10∶1,所得到的酯产率达 93 0 %。