Azolium azolates from reactions of neutral azoles with 1,3-dimethyl-imidazolium-2-carboxylate, 1,2,3-trimethyl-imidazolium hydrogen carbonate, and N,N-dimethyl-pyrrolidinium hydrogen carbonate
作者:Marcin Smiglak、C. Corey Hines、W. Matthew Reichert、Julia L. Shamshina、Preston A. Beasley、Parker D. McCrary、Steven P. Kelley、Robin D. Rogers
DOI:10.1039/c3nj00147d
日期:——
Utilizing previously reported synthetic protocols for the halide- and metal-free synthesis of organic salts, we have prepared a new group of imidazolium and pyrrolidinium azolate anion-based salts demonstrating the general applicability of the methodology and expanding our investigation into non ion exchange routes to potentially energetic ionic liquids. Eighteen salts, out of which six exhibit melting points below 100 °C, were prepared by a simple decarboxylation reaction, which resulted in clean formation of the new compounds without the need for extensive purification. The low stability of the H2CO3 by-product, and its decomposition to CO2 and H2O in aqueous media, allows for purification of the salts by evaporation only.
A substituent- and temperature-controllable NHC-derived zwitterionic catalyst enables CO<sub>2</sub> upgrading for high-efficiency construction of formamides and benzimidazoles
作者:Zhaozhuo Yu、Zhengyi Li、Lilong Zhang、Kaixun Zhu、Hongguo Wu、Hu Li、Song Yang
DOI:10.1039/d1gc01897c
日期:——
zwitterionic catalyst for efficient CO2 reductive upgrading via either N-formylation or further coupling with cyclization under mild conditions (25 °C, 1 atm CO2) using hydrosilane as a hydrogen source. More than 30 different alkyl and aromatic amines could be transformed into the corresponding formamides or benzimidazoles with remarkable yields (74%–98%). The electronic effect of the introduced substituent
近年来,将温室气体CO 2化学催化升级为有价值的化学品和生物燃料引起了广泛关注。在已报道的方法中,CO 2与胺的N-甲酰化由于其在构建含N 线性和环状骨架方面的多功能性而具有重要意义。这里,稳定的N-杂环卡宾-羧基加合物(NHC-CO 2)中制备的轻便和可作为用于高效CO可回收两性离子催化剂2还原升级经由任一Ñ -formylation或另外的耦合用温和的条件下环化(25 °C, 1 atm CO 2) 使用氢硅烷作为氢源。超过 30 种不同的烷基和芳香胺可以转化为相应的甲酰胺或苯并咪唑,产率显着(74%–98%)。发现引入的取代基对NHC-CO 2的电子效应明显影响两性离子催化剂的热稳定性和亲核性,这与其催化活性直接相关。此外,NHC-CO 2可以通过在特定温度下原位脱羧来提供CO 2,这取决于引入的取代基类型。实验和计算研究表明,NHC-CO 2上的羧基物质不仅是亲核中心,而且还是在氢化硅烷化过程中快速捕获或替代环境
catalysts for carbonate transfer hydrogenation from glycerol, requiring no additives in aqueousmedia. The most prolific catalyst of the nine examined, [Ir(NHC-Ph-SO3−)2CO2]Na (cat 7), effectively facilitates the reaction at low catalyst loading (10 ppm) at 150 °C using microwave or conventional heating. The cation of the carbonate salt significantly impacts catalytic activity, with highest activity
从生物质衍生的醇(如甘油)转移CO 2和碳酸盐进行氢化,以生成甲酸和乳酸,这是使两种废物流均价化的极具吸引力的途径,并且比直接进行碳酸盐加氢在热力学上更为有利。在此方法的第一个均相催化剂的开创性报告的基础上,我们扩展了具有磺酸盐官能化的翼尖的耐热且水溶性的Ir(I)和Ir(III)N-杂环卡宾(NHC)配合物以及用于碳酸酯从甘油转移加氢的稳健催化剂,在水性介质中无需任何添加剂。九个最多产的催化剂检查,物[Ir(NHC-PH-SO 3 - )2使用微波或常规加热,CO 2 ] Na(催化剂7)可有效地促进在150°C的低催化剂负载量(10 ppm)下的反应。碳酸盐的阳离子显着影响催化活性,在Cs 2 CO 3中观察到最高的活性(乳酸和甲酸在6小时内分别为27 850和13 350 TON,而K 2 CO 3则为15 400和8120 )。发现催化量的Cs +可显着增强K 2 CO 3的活性。在N
Next-Generation Water-Soluble Homogeneous Catalysts for Conversion of Glycerol to Lactic Acid
作者:Matthew Finn、J. August Ridenour、Jacob Heltzel、Christopher Cahill、Adelina Voutchkova-Kostal
DOI:10.1021/acs.organomet.8b00081
日期:2018.5.14
achieve quantitative conversion of glycerol in only 3 h. The high activity of these catalysts compared to nonsulfonated analogs is attributed to the stabilization the lactate product in aqueous media. The most active catalyst retains equal activity for crude glycerol. A mechanism is proposed for the most active catalyst precursor involving O–H oxidative addition of glycerol.
甘油增值的一种有吸引力的方法是催化转化为乳酸。通过克服与该反应的已知均相催化剂相关的溶解度挑战,我们表明具有磺酸盐官能化的翼尖的热稳健的Ir(I),Ir(III)和Ru(II)N-杂环卡宾(NHC)配合物非常多产对于该方法,除了碱水溶液外,不需要助溶剂。在常规加热和微波条件下都比较了催化剂的活性。活性最高的催化剂的TOF为45 592 h –1(微波)和3477 h –1(常规)中加入1当量的KOH,并以恒定速率进行至少8小时。尽管使用KOH观察到较高的活性,但该催化剂在较弱的碱K 2 CO 3(13000 h –1并同时形成甲酸)的情况下也具有很高的活性。可以修改方案以仅在3小时内实现甘油的定量转化。与非磺化类似物相比,这些催化剂的高活性归因于乳酸产物在水性介质中的稳定性。活性最高的催化剂对粗甘油保持相同的活性。对于活性最高的催化剂前体,提出了一种机制,涉及到O–H氧化氧化甘油。