5587-42-8Relevant articles and documents
Bifunctional temperature-sensitive amphiphilic acidic ionic liquids for preparation of biodiesel
Wu, Qin,Wan, Hualin,Li, Hansheng,Song, Haoran,Chu, Tonghua
, p. 74 - 79 (2013)
Several water-stable bifunctional temperature-sensitive amphiphilic Bronsted-acidic ionic liquids with an alkane sulfonic acid group and a polyether group were synthesized through polyethylene glycol monomethylether as raw material. The properties and structures of the ionic liquids were experimentally characterized. Esterification of oleic acid with methanol to biodiesel was investigated in various bifunctional temperature-sensitive amphiphilic acidic ionic liquids. The amphiphilicity, temperature-sensitive, polymerization degree, acidity and activity correlation for the ionic liquids were studied. It was found that their structures were consistent with the designed structure and their purities were high. Among all these ionic liquids, the ionic liquid - MPEG-350-ILs showed the best catalytic activity that is near to that of concentrated sulfuric acid, which is ascribed to its strong Bronsted acidity and amphiphilicity. The catalytic activity of each ILs is dependent on the polymerization degree of polyether cation. The catalytic activity decreased with lengthening polyether chain of ionic liquids. These ionic liquids exhibited temperature-sensitive property. The produced biodiesel could be separated via simple decantation and the ionic liquids could be reused.
Synthesis of 2, 2, 4-trimethyl-1, 3-pentaerediol monoisobutyrate catalyzed by homogeneous catalysis-liquid/liquid separation catalytic system based on Bibasic sites Ionic Liquids
Zhang, Shuying,Wang, Jiaomei,Liu, Xiangxue,Wang, Ke,Zhang, Chao,Song, Hongbing,Guo, Zhenmei,Lv, Zhiguo
, (2020)
Herein a novel homogeneous catalysis-liquid/liquid separation catalytic system based on 1, 8-diazabicyclo-[5.4.0] undec-7-ene (DBU)-functionalized, 1, 1, 3, 3-tetramethyl guanidine-functionalized and imidazolium-functionalized bibasic sites ionic liquids (BSILs) ([HDBU]IM, [Aemim]IM, [TMG]IM, [Aemim]Pro, [Aemim]Gly, [HDBU]Pro and [HDBU]Gly) with a room temperature liquid/liquid phase transition characteristic were reported. And for the first time, this novel catalytic system was employed for the synthesis of 2, 2, 4-trimethyl-1, 3-pentaerediol monoisobutyrate (CS-12), achieving homogeneous catalysis, easy recycling and long service-life of the catalyst. Additionally, the mechanism of homogeneous catalysis-biphasic separation might be explained by the solubility of reactant and product in BSILs/H2O catalytic system and the existence H-bonding between BSILs and H2O. Bibasic sites were confirmed by two endothermic peaks on the TG-DCS curve of [Aemim]IMC (the CO2 captured by [Aemim]IM).
Copper(I)-mediated CN/CC bond-forming reaction with tetrafluoroethylene for the synthesis of N-fluoroalkyl heteroarenes via an azacupration/coupling mechanism
Ishida, Naoyoshi,Adachi, Takuya,Iwamoto, Hiroaki,Ohashi, Masato,Ogoshi, Sensuke
supporting information, p. 442 - 444 (2021/03/15)
A novel copper(I)-mediated CN/CC bond-forming reaction involving tetrafluoroethylene (TFE), imidazolide or benz-imidazolide salts, and aryl iodides has been developed. This three-component coupling reaction can provide highly functionalized N-fluoroalkyl heteroaromatic compounds in up to 98% yield via a one-pot procedure. The azacupration of TFE with the copper(I) imidazolide species to afford the fluoroalkylcopper(I) complex is the key process in the transformation.
Iridium and ruthenium complexes of N-heterocyclic carbene- and pyridinol-derived chelates as catalysts for aqueous carbon dioxide hydrogenation and formic acid dehydrogenation: The role of the alkali metal
Siek, Sopheavy,Burks, Dalton B.,Gerlach, Deidra L.,Liang, Guangchao,Tesh, Jamie M.,Thompson, Courtney R.,Qu, Fengrui,Shankwitz, Jennifer E.,Vasquez, Robert M.,Chambers, Nicole,Szulczewski, Gregory J.,Grotjahn, Douglas B.,Webster, Charles Edwin,Papish, Elizabeth T.
, p. 1091 - 1106 (2017/12/08)
Hydrogenation reactions can be used to store energy in chemical bonds, and if these reactions are reversible, that energy can be released on demand. Some of the most effective transition metal catalysts for CO2 hydrogenation have featured pyridin-2-ol-based ligands (e.g., 6,6'-dihydroxybipyridine (6,6'-dhbp)) for both their proton-responsive features and for metal-ligand bifunctional catalysis. We aimed to compare bidentate pyridin-2-ol based ligands with a new scaffold featuring an N-heterocyclic carbene (NHC) bound to pyridin-2-ol. Toward this aim, we have synthesized a series of [CpIr(NHC-pyOR)Cl]OTf complexes where R = tBu (1), H (2), or Me (3). For comparison, we tested analogous bipyderived iridium complexes as catalysts, specifically [CpIr(6,6'-dxbp)Cl]OTf, where x = hydroxy (4Ir) or methoxy (5Ir); 4Ir was reported previously, but 5Ir is new. The analogous ruthenium complexes were also tested using [(η6-cymene)Ru(6,6'-dxbp)Cl]OTf, where x = hydroxy (4Ru) or methoxy (5Ru); 4Ru and 5Ru were both reported previously. All new complexes were fully characterized by spectroscopic and analytical methods and by single-crystal X-ray diffraction for 1, 2, 3, 5Ir, and for two [Ag(NHC-pyOR)2]OTf complexes 6 (R = tBu) and 7 (R = Me). The aqueous catalytic studies of both CO2 hydrogenation and formic acid dehydrogenation were performed with catalysts 1-5. In general, NHC-pyOR complexes 1-3 were modest precatalysts for both reactions. NHC complexes 1-3 all underwent transformations under basic CO2 hydrogenation conditions, and for 3, we trapped a product of its transformation, 3SP, which we characterized crystallographically., we trapped a product of its transformation, 3SP, which we characterized crystallographically.. For CO2 hydrogenation with base and dxbp-based catalysts, we observed that x = hydroxy (4Ir) is 5-8 times more active than x = methoxy (5Ir). Notably, ruthenium complex 4Ru showed 95% of the activity of 4Ir. For formic acid dehydrogenation, the trends were quite different with catalytic activity showing 4Ir Z> 4Ru and 4Ir ≈ 5Ir Secondary coordination sphere effects are important under basic hydrogenation conditions where the OH groups of 6,6'-dhbp are deprotonated and alkali metals can bind and help to activate CO2. Computational DFT studies have confirmed these trends and have been used to study the mechanisms of both CO2 hydrogenation and formic acid dehydrogenation.
