Direct oxidativecoupling of alcohols and amines is regarded as an effective and green approach for imine synthesis under mild conditions. In this work, Zn-doped γ-Al2O3 supported Au nanoparticles was demonstrated as highly active and selective heterogeneous catalyst for a series of imine productions with good to excellent yields, from alcohols and amines via direct oxidativecoupling under air atmosphere
醇和胺的直接氧化偶合被认为是在温和条件下合成亚胺的有效且绿色的方法。在这项工作中,锌掺杂的γ-Al 2 ö 3支持的Au纳米颗粒被证明为没有额外的空气气氛下,高活性和选择性的非均相催化剂进行一系列具有良好到优异的产率亚胺制作的,从通过直接氧化偶合醇和胺基础添加剂。研究了各种物理化学技术,包括ICP-MS,XRD,N 2物理吸附,TEM,XPS和CO 2- / NH 3 -TPD。分散良好的Au 0纳米粒子的平均大小约为 在反应性胺的存在下,发现2.9nm对活化醇非常有效。Zn 2+掺杂剂的量和催化剂制备过程中载体的煅烧温度显示出对调节苄醇氧化为苯甲醛的内在活性(即模型反应的速率确定步骤)的关键影响,据报道这是与活性表面氧种类和载体的酸碱性有关。在400°C下煅烧的0.4%Au / Zn 0.02 Al 2 O 3催化剂表现出最高的TOF(39.1 h -1)在60°C的条件下,在所有已报道的金基催化剂中,对亚苄基苯胺的收率均>
Efficient Imine Formation by Oxidative Coupling at Low Temperature Catalyzed by High‐Surface‐Area Mesoporous CeO
<sub>2</sub>
with Exceptional Redox Property
the structural and redox properties. The hsmCeO2 calcined at 400 °C shows the highest specific surfacearea (158 m2 g−1), the highest fraction of surface coordinatively unsaturated Ce3+ ions (18.2 %), and the highest concentration of reactive oxygen vacancies (2.4×1015 spins g−1). In the model reaction of oxidative coupling of benzyl alcohol and aniline, such an exceptional redox property of the hsmCeO2
高表面积介孔CeO 2(hsm CeO 2)是通过一种容易的有机模板诱导的均匀沉淀过程制备的,在低温下空气中没有伯醇和胺的碱存在下,在亚胺合成中显示出优异的催化活性。 。为了比较,还研究了不同热处理后的普通CeO 2和hsm CeO 2。XRD,N 2物理吸附,UV-拉曼光谱,H 2程序升温还原,O 2程序升温脱附,EPR光谱和X射线光电子能谱被用来揭示结构和氧化还原特性。这在400°C下煅烧的hsm CeO 2表现出最高的比表面积(158 m 2 g -1),最高的表面配位不饱和Ce 3+离子份额(18.2%)和最高的活性氧空位浓度(2.4× 10 15 旋转g -1)。在苯甲醇和苯胺的氧化偶合模型反应中,hsm CeO 2催化剂的这种出色的氧化还原性质可以促进苄叉基苯胺的形成(2.75和5.55 mmol h -1基于在无碱添加剂的空气中分别在60和80°C下> 99%的收率。它也
One-pot synthesis of Pd-promoted Ce–Ni mixed oxides as efficient catalysts for imine production from the direct <i>N</i>-alkylation of amine with alcohol
Pd–CeNiXOY catalyst surprisingly showed an enhanced imine yield (>99%) at a mild temperature of 60 °C. This catalyst exhibited good reusability, and moreover, demonstrated high performance towards imine synthesisfrom various amines with alcohols. The presence of Pd species and the Ni/Ce molar ratio showed a synergistic impact on the conversion of aniline, as well as on the product selectivity, which was believed
通过简单的一锅法沉淀法制备了由少量Pd(0.2 wt%)促进的具有不同Ni / Ce摩尔比的Ce-Ni混合氧化物。如此合成的CeNi X O Y和Pd–CeNi X O Y催化剂分别在不存在碱性添加剂的情况下,在O 2下,通过氧化偶合,直接用于胺和醇的N-烷基化反应。CeNi X O Y催化剂可在100°C的苯胺与苄醇的模型烷基化反应中提供> 99%的亚胺收率。钯促进的Pd–CeNi X O Y在60°C的温和温度下,该催化剂出人意料地显示出提高的亚胺收率(> 99%)。该催化剂显示出良好的可重复使用性,此外,还显示出由多种胺与醇合成亚胺的高性能。Pd物种的存在和Ni / Ce摩尔比对苯胺的转化以及产物的选择性具有协同作用,据信这与苯甲醇氧化为苯甲醇的内在活性的提高有关。苯甲醛。主要采用各种物理化学技术,包括ICP-MS,XRD,N 2吸附-脱附,UV-拉曼光谱,H 2 -TPR,TEM,
Heterogeneous Ni Catalysts for N-Alkylation of Amines with Alcohols
作者:Ken-ichi Shimizu、Naomichi Imaiida、Kenichi Kon、S. M. A. Hakim Siddiki、Atsushi Satsuma
DOI:10.1021/cs4001267
日期:2013.5.3
Ni/θ-Al2O3, which suggests the cooperation of the acid–basesite of θ-Al2O3. For a series of Ni/θ-Al2O3 catalysts with different particle size, the turnover frequency (TOF) per surface Ni increases with decreasing Ni mean particle size, indicating that low-coordinated Ni species and/or metal–support interface are active sites. From these results, we propose that the active site for this reaction is metal–support
已经制备了负载在各种载体上的镍纳米颗粒(Ni / MO x),并研究了胺与醇的N-烷基化反应。在这些催化剂中,镍/θ-Al系2 Ó 3通过原位H制备2的NiO -还原/θ-Al系2 ö 3烷烃具有最高的活性,在无添加剂条件下,它是苯胺和脂族胺与各种醇(苄基和脂族醇)的烷基化反应的可重复使用的多相催化剂。伯胺被转化为仲胺,仲胺被转化为叔胺。对于苯胺与脂肪醇的反应,该催化剂比基于贵金属的最新催化剂显示出更高的周转数(TON)。机理研究表明,反应是通过氢借入机理进行的。Ni催化剂的活性取决于载体材料的性质。酸碱双功能载体比碱性或酸性载体具有更高的活性,这表明载体上的酸碱位点是必需的。2 Ó 3,这表明θ-Al的酸-碱位点的合作2 Ó 3。对于一系列的Ni /的θ-Al系2 ö 3种催化剂具有不同的颗粒大小,转换频率(TOF)每面的Ni增加随镍平均粒径,这表明低配位的Ni物种和/或金属-支撑界面是
Solid base catalyzed highly efficient N-alkylation of amines with alcohols in a solvent-free system
Different from any other catalytic systems containing transition metals and additives, sodium hydroxide itself was found to be a unique and effective catalyst for the solvent-free synthesis of the secondary amines via the N-alkylation of amines with alcohols. For the reaction of aniline with benzyl alcohol, 99.6 mol% conversion of aniline and 99.5% selectivity of the product were achieved under optimal