Versatile Methods for the Synthesis of Si(OR)3-Functionalised Imidazolium Salts, Potential Precursors for Heterogeneous NHC Catalysts and Composite Materials
Aerobic Oxidation of Alcohols Catalyzed by <i>in Situ</i> Generated Gold Nanoparticles inside the Channels of Periodic Mesoporous Organosilica with Ionic Liquid Framework
In situ generated gold nanoparticles inside the nanospaces of periodic mesoporous organosilica with an imidazolium framework ([email protected]) were found to be highly active, selective, and reusable catalysts for the aerobicoxidation of activated and nonactivated alcohols under mild reaction conditions. The catalyst was characterized by nitrogen adsorption–desorption measurement, thermogravimetric
发现具有咪唑骨架的周期性介孔有机硅纳米空间内的原位生成的金纳米粒子是高活性,选择性和可重复使用的催化剂,可在温和的反应条件下对活化和非活化醇进行好氧氧化。该催化剂的特征在于氮吸附-解吸测量,热重分析(TGA),透射电子显微镜(TEM),元素分析(EA),漫反射红外傅里叶变换光谱(DRIFT),X射线光电子能谱(XPS)和电感耦合等离子体原子发射光谱法(ICP-AES)。在Cs 2 CO 3(35°C)或K 2的存在下,该催化剂表现出优异的催化活性。一氧化碳3(60°C)作为反应基础在甲苯中作为反应溶剂。在两种反应条件下,各种类型的醇(最多35个实例),包括活化的苄基,伯和仲脂族,杂环和具有挑战性的环状脂族醇,都以良好的产率和选择性很好地转化为预期的羰基化合物。还回收了催化剂并将其再利用至少七个反应循环。来自三个独立浸出测试的数据表明,浸出金颗粒的量可以忽略不计(<0.2 ppm)。据信,桥
Self-assembled organic–inorganic hybrid silica with ionic liquid framework: a novel support for the catalytic enantioselective Strecker reaction of imines using Yb(OTf)3–pybox catalyst
作者:Babak Karimi、Aziz Maleki、Dawood Elhamifar、James H. Clark、Andrew J. Hunt
DOI:10.1039/c0cc01426e
日期:——
Yb(OTf)3âpybox is immobilized in a novel self-assembled ionic liquid hybrid silica and has been successfully applied as a catalyst for the asymmetric Strecker hydrocyanation of aldimines. This catalytic system can be reused for at least 6 times without any significant loss of activity and enantioselectivity.
Design and synthesis of magnetic Fe<sub>3</sub>O<sub>4</sub>@NFC-ImSalophCu nanocatalyst based on cellulose nanofibers as a new and highly efficient, reusable, stable and green catalyst for the synthesis of 1,2,3-triazoles
VSM, and ICP spectroscopy. This catalyst shows the dual function of the metal sites and imidazolium moieties. The catalytic system mentioned above also showed excellent activity in the synthesis of bis 1,4-disubstituted 1,2,3-triazoles. Moreover, the catalyst could be recycled and reused for four cycles without any decrease in its catalyticactivity.
Fe 3 O 4 @NFC-ImSalophCu催化剂作为一种高度稳定、可重复使用、活性高的绿色催化剂,用于苯甲酰溴、叠氮化钠和炔烃的一锅三组分反应合成1,2,3-三唑类化合物。制备了含有咪唑鎓离子相的Cu( II )-席夫碱配合物,并将其修饰在核壳Fe 3 O 4 @NFC磁性纳米粒子(Fe 3 O 4 @NFC-ImSalophCu)上,并用作高效催化剂。采用 FT-IR 光谱、FE-SEM、TEM、XRD 光谱、EDX 光谱、VSM 和 ICP 光谱对非均相催化剂进行了表征。该催化剂显示出金属位点和咪唑鎓部分的双重功能。上述催化体系在双1,4-二取代1,2,3-三唑的合成中也表现出优异的活性。此外,该催化剂可以回收并重复使用四个周期,其催化活性没有任何降低。
Temperature-Dependent Immobilization of a Tungsten Peroxo Complex That Catalyzes the Hydroxymethoxylation of Olefins
immobilization of tungsten peroxo complex was highly temperature-dependent. The tungsten peroxo complex can dissociate and diffuse into the liquid phase at reaction temperature, resulting in a homogeneous reaction. Nevertheless, the catalytically active species was anchored on the imidazole-functionalized silica by hydrogen bonding as the temperature was lowered to 0 °C after the reaction, which thus offered a
合成了由二齿吡啶甲酸配体稳定的过氧钨配合物,然后成功地将其固定在咪唑官能化的二氧化硅上。固定化的钨基催化剂被用作由烯烃和甲醇与H2 O2一锅合成β-烷氧基醇的有效催化剂。关于催化剂评估和通过各种方法表征的结果,证明了过氧化钨配合物的固定化高度依赖于温度。过氧化钨络合物可以在反应温度下解离并扩散到液相中,从而导致均相反应。然而,随着反应后温度降低至0°C,催化活性物质通过氢键键合固定在咪唑官能化的二氧化硅上,因此,它提供了一种高效的方法来使催化剂连续循环使用。另外,在相对温和的条件下,H 2 O 2可将各种烯烃以良好的转化率和选择性转化为相应的β-烷氧基醇。
Nano-silica supported acidic ionic liquid as an efficient catalyst for the multi-component synthesis of indazolophthalazine-triones and bis-indazolophthalazine-triones
A supported ionic liquid bearing sulfonic acid groups was synthesized by anchoring 3-sulfopropyl-1-(3-propyltrimethoxysilane)imidazolium hydrogen sulfate onto nano-silica and characterized by FT-IR spectroscopy, elemental analysis and scanning electron microscopy (SEM) techniques. This catalyst was used for the efficient one-pot multi-component synthesis of indazolophthalazine-triones and bis-indazolophthalazine-triones. Moreover, the catalyst could be reused at least seven times without any significant loss of activity.