- Bifunctional phase-transfer catalysts for fixation of CO2 with epoxides under ambient pressure
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A series of bifunctional phase-transfer catalysts with a quaternary onium center and a hydrogen-bonding donor group were prepared for the fixation of CO2 with commercially available epoxides under mild conditions by using a CO2 balloon (1 atm). In the presence of 2.5 mol% of achiral bifunctional phase-transfer catalysts, cyclic carbonates were obtained in good to excellent yields (up to 95%). Additionally, optical carbonates and epoxides were obtained through the kinetic resolution of rac-epoxides by 1 mol% of chiral bifunctional phase-transfer catalysts with low enantioselectivities. These catalysts featured a simple synthetic route, good modularity and high efficiency.
- Li, Yue-Dan,Cui, Dong-Xiao,Zhu, Jun-Chao,Huang, Ping,Tian, Zhuang,Jia, Yan-Yan,Wang, Ping-An
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Read Online
- Synthesis of Ionic Liquids as Novel Nanocatalysts for Fixation of Carbon Dioxide with Epoxides by Using a Carbon Dioxide Balloon
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Abstract: In the present study, the nanocatalyst of imidazolium based ionic liquids (ILs) is synthesized for the fixation of carbon dioxide (CO2) under moderate conditions by utilizing a balloon of CO2 with commercially available epoxides. IL incorporated porous dendritic fibrous nanosilica (DFNS) catalyst (IL/DFNS) was designed and synthesized. The synthesized catalyst was characterized using N2 absorption desorption isotherm, XPS, SEM, EDX, TGA, HR-TEM, and AFM. For cyclic carbonate, an environmental friendly catalyst of porous IL/DFNS indicate highly impressive catalytic efficiency from CO2 through CO2 fixation and epoxides under mild condition. Attendance of polar hydroxyl and anion exchange nature groups of IL frame work to high surface area is known as the main aspect to be reliable for elevated catalytic efficiency and also advance in stability of catalyst and providing a proper recyclability. Graphic Abstract: [Figure not available: see fulltext.].
- Zhang, Pu,Zhiani, Rahele
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p. 2254 - 2266
(2020/02/18)
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- Organocatalytic valorisation of glycerol: Via a dual NHC-catalysed telescoped reaction
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A general telescoped reaction for the NHC-catalysed carbonation and aerobic esterification of glycerol and 2-amino-2-methylpropane-1,3-diol has been developed. The reaction provides highly functionalised glycerol derivatives in good to excellent yields (up to 95%) using low catalyst loadings and ambient conditions.
- Axelsson,Antoine-Michard,Sundén
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supporting information
p. 2477 - 2481
(2017/07/17)
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- METHOD OF CONVERTING ALCOHOL TO HALIDE
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The present invention relates to a method of converting an alcohol into a corresponding halide. This method comprises reacting the alcohol with an optionally substituted aromatic carboxylic acid halide in presence of an N-substituted formamide to replace a hydroxyl group of the alcohol by a halogen atom. The present invention also relates to a method of converting an alcohol into a corresponding substitution product. The second method comprises: (a) performing the method of the invention of converting an alcohol into the corresponding halide; and (b) reacting the corresponding halide with a nucleophile to convert the halide into the nucleophilic substitution product.
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Page/Page column 51; 179; 180
(2017/01/02)
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- Tetraarylphosphonium Salt-Catalyzed Carbon Dioxide Fixation at Atmospheric Pressure for the Synthesis of Cyclic Carbonates
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Phosphonium salts exhibit great utility in organic synthesis. However, tetraarylphosphonium salts (TAPS) have found limited use as catalysts. We demonstrate the TAPS-catalyzed carbon dioxide fixation at atmospheric pressure for the coupling reaction with
- Toda, Yasunori,Komiyama, Yutaka,Kikuchi, Ayaka,Suga, Hiroyuki
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p. 6906 - 6910
(2016/10/14)
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- Cycloaddition of COto epoxides catalyzed by N-heterocyclic carbene (NHC)-ZnBrsystem under mild conditions
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A very simple and convenient method toward coupling of COwith epoxides catalyzed by NHC/ZnBrhas been developed. This catalytic system exhibits excellent activity and selectivity in the cycloaddition reactions of COto terminal epoxides. The reactions can e
- Liu, Xiang,Cao, Changsheng,Li, Yunfei,Guan, Pei,Yang, Longguang,Shi, Yanhui
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supporting information; experimental part
p. 1343 - 1348
(2012/07/03)
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- Converting wastes into added value products: From glycerol to glycerol carbonate, glycidol and epichlorohydrin using environmentally friendly synthetic routes
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Glycerol carbonate, synthesised via a non-phosgene route using glycerol and CO2 or urea in presence of a heterogeneous catalyst, was efficiently converted into a series of derivatives through the functionalization of the -OH moiety, using high yield, high selectivity synthetic routes not affecting the carbonate functionality. So, for example, glycerol carbonate was converted into epichlorohydrin, a product that has a large industrial application, under very mild conditions, using a two-step reaction with a 98% yield and 100% selectivity. The high yield and mild reaction conditions (very often close to the ambient conditions) make the environmentally friendly synthetic approach described in this work of potential applicative interest. All compounds prepared were fully characterized.
- Dibenedetto, Angela,Angelini, Antonella,Aresta, Michele,Ethiraj, Jayashree,Fragale, Carlo,Nocito, Francesco
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experimental part
p. 1308 - 1313
(2011/04/12)
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- Cyclic carbonate synthesis catalysed by bimetallic aluminium-salen complexes
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The development of bimetallic aluminium-salen complexes [{Al-(salen)} 2O] as catalysts for the synthesis of cyclic carbonates (including the commercially important ethylene and propylene carbonates) from a wide range of terminal epoxides in the presence of tetrabutylammonium bromide as a cocatalyst is reported. The bimetallic structure of one complex was confirmed by X-ray crystallography. The bimetallic complexes displayed exceptionally high catalytic activity and in the presence of tetrabutylammonium bromide could catalyse cyclic carbonate synthesis at atmospheric pressure and room temperature. Catalyst-reuse experiments demonstrated that one bimetallic complex was stable for over 60 reactions, though the tetrabutylammonium bromide decomposed in situ by a retro-Menschutkin reaction to form tributylamine and had to be regularly replaced. The mild reaction conditions allowed a full analysis of the reaction kinetics to be carried out and this showed that the reaction was first order in aluminium complex concentration, first order in epoxide concentration, first order in carbon dioxide concentration (except when used in excess) and unexpectedly second order in tetrabutylammonium bromide concentration. Further kinetic experiments demonstrated that the tributylamine formed in situ was involved in the catalysis and that addition of butyl bromide to reconvert the tributylamine into tetrabutylammonium bromide resulted in inhibition of the reaction. The reaction kinetics also indicated that no kinetic resolution of racemic epoxides was possible with this class of catalysts, even when the catalyst was derived from a chiral salen ligand. However, it was shown that if enantiomerically pure styrene oxide was used as substrate, then enantiomerically pure styrene carbonate was formed. On the basis of the kinetic and other experimental data, a catalytic cycle that explains why the bimetallic complexes display such high catalytic activity has been developed.
- Clegg, William,Harrington, Ross W.,North, Michael,Pasquale, Riccardo
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supporting information; experimental part
p. 6828 - 6843
(2010/08/07)
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- SYNTHESIS OF CYCLIC CARBONATES IN THE PRESENCE OF DIMERIC ALUMINIUM (SALEN) CATALYSTS
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A process for the production of cyclic carbonates comprising contacting an epoxide with carbon dioxide in the presence of a dimeric aluminium(salen) catalyst, and a co-catalyst capable of supplying Y-, where Y is selected from Cl, Br and I, where the dimeric aluminium(salen) catalyst is of formula I:
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Page/Page column 26-27; 298
(2008/12/08)
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