新型多功能三溴三聚氰胺催化剂催化醇甲酰化和乙酰化反应(英文)

Tribromo melamine has been found to be an efficient and green organocatalyst for the acetylation and formylation reactions of alcohols with acetic anhydride and ethyl formate at room temperature and under mild reaction conditions.     

铌改性的Pd/Al2O3催化剂催化苯燃烧反应简

采用浸渍法制备了Nb改性的Pd/Al2O3催化剂,考察了该催化剂催化苯燃烧反应性能,并研究了催化剂的稳定性. 结果表明,Nb的添加明显提高了Pd/Al2O3催化剂性能,在195 ℃时苯转化率达到90%,苯的完全燃烧温度降低了40 ℃. 采用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、H2 程序升温还原(H2-TPR)、NH3程序升温脱附(NH3-TPD)和氮气吸附等手段对催化剂进行了表征,结果表明,Nb的加入不仅提高了Pd物种的分散度,同时改变了部分Pd的价态,形成适宜反应的PdO-Pd物种,并促进了催化剂表面氧浓度的增加,使氧物种氧化能力增强,从而提高了催化性能. 1%Pd-5%Nb/Al2O3催化剂的催化活性高于2.0%Pd/Al2O3催化剂.     

Mg-Al水滑石催化甘油与碳酸二甲酯的酯交换反应简

报道了温和条件下甘油和碳酸二甲酯在一系列不同Mg/Al比（0.5-6）的Mg-Al水滑石催化下合成碳酸甘油酯（GC）的反应. 发现,Mg-Al水滑石对该反应具有很高的GC选择性,其中Mg/Al=2经400℃处理所得水滑石催化效率最高：70 ℃反应3 h甘油转化率达66.9%时,GC选择性维持在97%以上. 表征结果表明,水滑石样品的比表面积、孔径、结晶度和表面碱性对其催化活性影响很大.     

高效可回收多相催化剂SiO2-Cu2O催化伯胺和仲胺苄基化反应简

A mild, effective, and selective procedure is reported for the mono N-benzylation and N,N-dibenzylation of primary amines as well as mono N-benzylation of secondary amines using silica-supported copper(I) oxide in water. The silica-supported Cu₂O was generated in situ by the reaction of Fehling solution and glucose at 100 ℃ onto activated silica. The catalyst was filtered, washed with water, and oven-dried, and was characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and atomic absorption spectroscopy. The prepared Cu₂O-SiO₂ was found to be thermally stable up to 325 ℃. The copper was uniformly distributed onto the surface of the silica, and the mean particle diameter was 7 nm. The catalyst served as a selective heterogenous catalyst for the N-benzylation of primary and secondary amines. The catalyst is recyclable and was used effectively upto fifth run without a significant loss of catalytic activity. Various reaction solvents including water, acetonitrile, and toluene were screened for N-benzylation of amines, and the success of the aqueous system highlights the low environmental impact of the procedure.     

Ni-Mo氮化物催化剂:合成及其丙烷氨氧化催化性能简

分别采用溶胶-凝胶法、旋转蒸发微波干燥法、共沉淀法、浸渍法和机械混合法制备Ni-Mo氧化物前驱体. 以H₂和N₂的混合气为氮化气体,采用程序升温氮化法合成了镍钼氮化物催化剂. 利用X射线衍射、总氮含量分析、X射线光电子能谱及H₂程序升温还原对Ni-Mo氧化物前体及氮化物催化剂进行了表征. 将上述Ni-Mo氮化物催化剂用于丙烷氨氧化反应中. 结果表明,Ni-Mo氧化物前驱体的制备方法影响其氮化物催化剂上丙烷氨氧化反应性能. Ni-Mo氮化物催化剂中氮物种的移动性及反应性对产物丙烯腈选择性的影响较大,共沉淀法制备的催化剂存在大量的活性氮物种,因而具有良好的催化丙烷氨氧化反应活性.     

Morphology and Phase Composition ofGelatin-Starch Blends简

Morphology and phase compositions of different starch-gelatin blends were investigated by various microscopes: optical, SEM and synchrotron FTIR microscopy. A high amylose(80%) corn starch, grafted with hydroxypropyl to enhance flexibilty and hydrophilicity, and plasticized by poly(ethylene glycol)(PEG), was used in this work. SEM revealed that the surface became smoother after adding PEG. Optical microscopy observation revealed that compatibility between gelatin and starch was improved by adding PEG. An FTIR beam focused on a 5 μm× 5 μm detection area by the micro-spectroscope was used to map chemical composition. The ratio of areas of the saccharide bands(1180–953 cm 1) and the amide I and II bands(1750–1483 cm 1) was used to monitor the relative distributions of the two components in the blends. The FTIR maps indicated that gelatin constituted the continuous phase up to 80% of starch content. All of the FTIR spectra showed contributions from both starch and gelatin absorptions, therefore indicating that complete demixing with pure starch and gelatin domains did not occur. The PEG improved the compatibility of the gelatin-starch blends.     

Silica-bonded N-propyl sulfamic acid as an efficient catalyst for the formylation and acetylation of alcohols and amines under heterogeneous conditions

A simple and efficient procedure for the preparation of silica-bonded N-propyl sulfamic acid (SBNPSA) by the reaction of 3-aminopropylsilica (1) and chlorosulfonic acid in chloroform is described. This solid acid is employed as a new catalyst for the formylation of alcohols and amines with ethyl formate under mild and heterogeneous conditions at room temperature with good to excellent yields. Also, SBNPSA catalyzed acetylation of various alcohols and amines with acetic anhydride at room temperature.     

2-(Sulfooxy)propane-1,2,3-tricarboxylic acid as novel and versatile catalyst for the formylation of alcohols and amines using ethyl formate under neat conditions

2-(Sulfooxy)propane-1,2,3-tricarboxylic acid(supported on silica gel) has been introduced as novel and green catalyst for the formylation of alcohols and amines with ethyl formate,as mild formylation agent,under neat conditions at room temperature.     

Silphos [PCl3−n(SiO2)n]: a heterogeneous phosphine reagent for formylation and acetylation of alcohols and amines with ethyl formate and acetate

Alcohols and amines are formylated and acetylated in the presence of Silphos [PCl_3−n(SiO₂)_n] in ethyl formate and ethyl acetate in high to excellent yields. This procedure provides a method to separate the product by a simple filtration.     

p-Toluenesulfonyl chloride as a new and effective catalyst for acetylation and formylation of hydroxyl compounds under mild conditions

<正>The catalytic application of p-toluenesulfonyl chloride for efficient acetylation of various types of alcohols and phenols with acetic anhydride in solvent-free conditions is reported.Also structurally diverse alcohols were formylated using formic acid based on the use of catalytic amount of p-toluenesulfonyl chloride under solvent-free condition.The reactions were carried out in short reaction time and in good to excellent yields at room temperature.     

Electron-deficient [Ti(salophen)(OTf)2]: A new and highly efficient catalyst for the acetylation of alcohols and phenols with acetic anhydride

In the present work, a highly efficient method for acetylation of alcohols and phenols with acetic anhydride catalyzed by high-valent [Ti^IV(salophen)(OTf)₂] is reported. Under these conditions, primary, secondary and tertiary alcohols as well as phenols were acetylated with short reaction times and high yields. The catalyst was reused several times without loss of its catalytic activity.     

新的金属氧化物纳米催化剂CuO-ZnO高效催化醇化学选择性乙酰化（英文）

A new method has been developed for the chemoselective acetylation of alcohols with acetic anhy‐dride in the presence of phenols using a novel,recyclable Cu O‐Zn O nanocatalyst.The catalyst was synthesized using the co‐precipitation method and characterized by N2 adsorption‐desorption,X‐ray diffraction,scanning electron microscopy,transmission electron microscopy and energy dis‐persion scanning analyses.Furthermore,this catalyst could be recycled up to six times without significant loss in its activity.     

Efficient approach for the chemoselective acetylation of alcohols catalyzed by a novel metal oxide nanocatalyst CuO-ZnO

A new method has been developed for the chemoselective acetylation of alcohols with acetic anhy‐dride in the presence of phenols using a novel, recyclable CuO‐ZnO nanocatalyst. The catalyst was synthes...     

Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols

The use of readily available ethyl acetate in the presence of iodine as an alternative acetylating agent is reported. Amines and phenols were unreactive under the examined reaction conditions, indicating that the method is highly chemoselective.     

A Novel Application of Ammonium Formate/Palladium on Carbon for Selective Reduction of the Heterocyclic Ring in Quinolines and Isoquinolines

Ammonium formate/palladium on carbon was found to be a convenient system for selective reduction, in good yields, of the heterocyclic ring in quinoline and isoquinoline derivatives.