The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sheng Dai - One of the best experts on this subject based on the ideXlab platform.
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Superbase derived protic ionic liquids with chelating fluorinated anions
Tetrahedron Letters, 2011Co-Authors: Jason R Bell, Huimin Luo, Sheng DaiAbstract:Abstract Eighteen new protic ionic liquids were synthesized in one step from five organic Superbases and five commercially available fluorinated β-diketones. Physical properties of the ionic liquids, including thermal decomposition temperature were determined. Nine of the ionic liquids were examined as extraction media for La 3+ , with some very large distribution coefficients obtained.
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equimolar co2 capture by imidazolium based ionic liquids and Superbase systems
Green Chemistry, 2010Co-Authors: Congmin Wang, Huimin Luo, Xiaoyan Luo, Sheng DaiAbstract:Imidazolium-based ionic liquids continue to attract interest in many areas of chemistry because of their low melting points, relatively low viscosities, ease of synthesis, and good stabilities against oxidative and reductive conditions. However, they are not totally inert under many conditions due to the intrinsic acidity of hydrogen at the C-2 position in the imidazolium cation. In this work, this intrinsic acidity was exploited in combination with an organic Superbase for the capture of CO2 under atmospheric pressure. During the absorption of CO2, the imidazolium-based ionic liquid containing an equimolar Superbase reacted with CO2 to form a liquid carboxylate salt so that the equimolar capture of CO2 with respect to the base was achieved. The effects of ionic liquid structures, types of organic Superbases, absorption times, and reaction temperatures on the capture of CO2 were investigated. Our results show that this integrated ionic liquid–Superbase system is capable of rapid and reversible capture of about 1 mol CO2 per mole of ionic liquid. Furthermore, the captured CO2 can be readily released by either heating or bubbling N2, and recycled with little loss of its capture capability. This efficient and reversible catch-and-release process using the weak acidity of the C-2 proton in nonvolatile imidazolium-based ionic liquids provides a good alternative to the current CO2 capture methods that use volatile alkanols, amines, or water.
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reversible and robust co2 capture by equimolar task specific ionic liquid Superbase mixtures
Green Chemistry, 2010Co-Authors: Congmin Wang, Huimin Luo, Shannon M Mahurin, Gary A Baker, Sheng DaiAbstract:Integrated sorption systems consisting of 1 : 1 mixtures of an alcohol-functionalized ionic liquid and a Superbase were found to be effective for CO2 capture under atmospheric pressure, eliminating the use of volatile n-alkanols or water. Conversely, by using the current approach, there is no longer a requirement for maintaining scrupulously dry conditions. The effect of ionic liquid structure, choice of Superbase, their relative ratios, the sorption temperature, and the reaction time on the absorption and release of CO2 were investigated. Our results demonstrate that (i) this integrated ionic liquid–Superbase system is capable of rapid and reversible capture of nearly one mole of CO2 per mole of Superbase, (ii) the captured CO2 can be readily released by either mild heating or bubbling with an insert gas (N2, Ar), and (iii) this novel CO2 chemisorption platform can be recycled with minimal loss of activity. This efficient and fully reversible catch-and-release process using non-volatile, task-specific ionic liquids provides an excellent alternative to current CO2 capture technologies, which are based largely around volatile alkanols or alkylamines. Furthermore, our integrated ionic liquid–Superbase system can be used as a novel medium for supported liquid membranes, for which they demonstrate both good selectivity and permeability in model CO2/N2 gas separations.
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ultrastable Superbase derived protic ionic liquids
Journal of Physical Chemistry B, 2009Co-Authors: Huimin Luo, Gary A Baker, Je Seung Lee, Richard M Pagni, Sheng DaiAbstract:Protic ionic liquids are synthesized via proton transfer from acids to organic bases. One of the key issues associated with conventional protic ionic liquids is the thermal instability resulting from temperature-induced decomposition via reverse proton transfer. This shortcoming significantly hampers the use of these protic ionic liquids in separations, electrochemical capacitors, fuel cells, and so forth. Herein we show that it is possible to prepare protic ionic liquids with thermal stabilities approaching those of common aprotic ionic liquids. Our new class of protic ionic liquids, derived via integrated neutralization and metathesis of superbasic phosphazenes or guanidines, exhibits exceptionally low vapor pressures at 150 °C while being stable to strong alkali agents such as aqueous KOH, suggesting potential in energy-related applications, including electrochemical capacitors and PEM-type fuel cells.
Congmin Wang - One of the best experts on this subject based on the ideXlab platform.
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equimolar co2 capture by imidazolium based ionic liquids and Superbase systems
Green Chemistry, 2010Co-Authors: Congmin Wang, Huimin Luo, Xiaoyan Luo, Sheng DaiAbstract:Imidazolium-based ionic liquids continue to attract interest in many areas of chemistry because of their low melting points, relatively low viscosities, ease of synthesis, and good stabilities against oxidative and reductive conditions. However, they are not totally inert under many conditions due to the intrinsic acidity of hydrogen at the C-2 position in the imidazolium cation. In this work, this intrinsic acidity was exploited in combination with an organic Superbase for the capture of CO2 under atmospheric pressure. During the absorption of CO2, the imidazolium-based ionic liquid containing an equimolar Superbase reacted with CO2 to form a liquid carboxylate salt so that the equimolar capture of CO2 with respect to the base was achieved. The effects of ionic liquid structures, types of organic Superbases, absorption times, and reaction temperatures on the capture of CO2 were investigated. Our results show that this integrated ionic liquid–Superbase system is capable of rapid and reversible capture of about 1 mol CO2 per mole of ionic liquid. Furthermore, the captured CO2 can be readily released by either heating or bubbling N2, and recycled with little loss of its capture capability. This efficient and reversible catch-and-release process using the weak acidity of the C-2 proton in nonvolatile imidazolium-based ionic liquids provides a good alternative to the current CO2 capture methods that use volatile alkanols, amines, or water.
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carbon dioxide capture by Superbase derived protic ionic liquids
Angewandte Chemie, 2010Co-Authors: Congmin Wang, Deen Jiang, Haoran LiAbstract:Protic ionic liquids (PILs) from a Superbase and fluorinated alcohol, imidazole, pyrrolinone, or phenol were designed to capture CO{sub 2} based on the reactivity of their anions to CO{sub 2}. These PILs are capable of rapid and reversible capture of about one equivalent of CO{sub 2}, which is superior to those sorption systems based on traditional aprotic ILs.
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reversible and robust co2 capture by equimolar task specific ionic liquid Superbase mixtures
Green Chemistry, 2010Co-Authors: Congmin Wang, Huimin Luo, Shannon M Mahurin, Gary A Baker, Sheng DaiAbstract:Integrated sorption systems consisting of 1 : 1 mixtures of an alcohol-functionalized ionic liquid and a Superbase were found to be effective for CO2 capture under atmospheric pressure, eliminating the use of volatile n-alkanols or water. Conversely, by using the current approach, there is no longer a requirement for maintaining scrupulously dry conditions. The effect of ionic liquid structure, choice of Superbase, their relative ratios, the sorption temperature, and the reaction time on the absorption and release of CO2 were investigated. Our results demonstrate that (i) this integrated ionic liquid–Superbase system is capable of rapid and reversible capture of nearly one mole of CO2 per mole of Superbase, (ii) the captured CO2 can be readily released by either mild heating or bubbling with an insert gas (N2, Ar), and (iii) this novel CO2 chemisorption platform can be recycled with minimal loss of activity. This efficient and fully reversible catch-and-release process using non-volatile, task-specific ionic liquids provides an excellent alternative to current CO2 capture technologies, which are based largely around volatile alkanols or alkylamines. Furthermore, our integrated ionic liquid–Superbase system can be used as a novel medium for supported liquid membranes, for which they demonstrate both good selectivity and permeability in model CO2/N2 gas separations.
Huimin Luo - One of the best experts on this subject based on the ideXlab platform.
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Superbase derived protic ionic liquids with chelating fluorinated anions
Tetrahedron Letters, 2011Co-Authors: Jason R Bell, Huimin Luo, Sheng DaiAbstract:Abstract Eighteen new protic ionic liquids were synthesized in one step from five organic Superbases and five commercially available fluorinated β-diketones. Physical properties of the ionic liquids, including thermal decomposition temperature were determined. Nine of the ionic liquids were examined as extraction media for La 3+ , with some very large distribution coefficients obtained.
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equimolar co2 capture by imidazolium based ionic liquids and Superbase systems
Green Chemistry, 2010Co-Authors: Congmin Wang, Huimin Luo, Xiaoyan Luo, Sheng DaiAbstract:Imidazolium-based ionic liquids continue to attract interest in many areas of chemistry because of their low melting points, relatively low viscosities, ease of synthesis, and good stabilities against oxidative and reductive conditions. However, they are not totally inert under many conditions due to the intrinsic acidity of hydrogen at the C-2 position in the imidazolium cation. In this work, this intrinsic acidity was exploited in combination with an organic Superbase for the capture of CO2 under atmospheric pressure. During the absorption of CO2, the imidazolium-based ionic liquid containing an equimolar Superbase reacted with CO2 to form a liquid carboxylate salt so that the equimolar capture of CO2 with respect to the base was achieved. The effects of ionic liquid structures, types of organic Superbases, absorption times, and reaction temperatures on the capture of CO2 were investigated. Our results show that this integrated ionic liquid–Superbase system is capable of rapid and reversible capture of about 1 mol CO2 per mole of ionic liquid. Furthermore, the captured CO2 can be readily released by either heating or bubbling N2, and recycled with little loss of its capture capability. This efficient and reversible catch-and-release process using the weak acidity of the C-2 proton in nonvolatile imidazolium-based ionic liquids provides a good alternative to the current CO2 capture methods that use volatile alkanols, amines, or water.
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reversible and robust co2 capture by equimolar task specific ionic liquid Superbase mixtures
Green Chemistry, 2010Co-Authors: Congmin Wang, Huimin Luo, Shannon M Mahurin, Gary A Baker, Sheng DaiAbstract:Integrated sorption systems consisting of 1 : 1 mixtures of an alcohol-functionalized ionic liquid and a Superbase were found to be effective for CO2 capture under atmospheric pressure, eliminating the use of volatile n-alkanols or water. Conversely, by using the current approach, there is no longer a requirement for maintaining scrupulously dry conditions. The effect of ionic liquid structure, choice of Superbase, their relative ratios, the sorption temperature, and the reaction time on the absorption and release of CO2 were investigated. Our results demonstrate that (i) this integrated ionic liquid–Superbase system is capable of rapid and reversible capture of nearly one mole of CO2 per mole of Superbase, (ii) the captured CO2 can be readily released by either mild heating or bubbling with an insert gas (N2, Ar), and (iii) this novel CO2 chemisorption platform can be recycled with minimal loss of activity. This efficient and fully reversible catch-and-release process using non-volatile, task-specific ionic liquids provides an excellent alternative to current CO2 capture technologies, which are based largely around volatile alkanols or alkylamines. Furthermore, our integrated ionic liquid–Superbase system can be used as a novel medium for supported liquid membranes, for which they demonstrate both good selectivity and permeability in model CO2/N2 gas separations.
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ultrastable Superbase derived protic ionic liquids
Journal of Physical Chemistry B, 2009Co-Authors: Huimin Luo, Gary A Baker, Je Seung Lee, Richard M Pagni, Sheng DaiAbstract:Protic ionic liquids are synthesized via proton transfer from acids to organic bases. One of the key issues associated with conventional protic ionic liquids is the thermal instability resulting from temperature-induced decomposition via reverse proton transfer. This shortcoming significantly hampers the use of these protic ionic liquids in separations, electrochemical capacitors, fuel cells, and so forth. Herein we show that it is possible to prepare protic ionic liquids with thermal stabilities approaching those of common aprotic ionic liquids. Our new class of protic ionic liquids, derived via integrated neutralization and metathesis of superbasic phosphazenes or guanidines, exhibits exceptionally low vapor pressures at 150 °C while being stable to strong alkali agents such as aqueous KOH, suggesting potential in energy-related applications, including electrochemical capacitors and PEM-type fuel cells.
B A Trofimov - One of the best experts on this subject based on the ideXlab platform.
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cascade assembly of 4 5 6 7 tetrahydroindole from cyclohexanone oxime and acetylene in the koh dmso Superbase medium a quantum chemical study
Journal of Organic Chemistry, 2020Co-Authors: Alexander S Bobkov, N M Vitkovskaya, B A TrofimovAbstract:Pyrrole synthesis from ketoximes and acetylene in the KOH/dimethyl sulfoxide (DMSO) Superbase medium (here abbreviated as the KOA reaction) provided access to a wide variety of 2-substituted and 2,3-disubstituted pyrroles from the available starting materials (enolizable ketones and acetylene). All steps of the KOA reaction mechanism are studied, for the first time, in detail at a uniform theoretical level for the cascade assembly of 4,5,6,7-tetrahydroindole from cyclohexanone oxime and acetylene. Our results explain the reasons why some earlier postulated intermediates have not been detected during the reaction. Alternative channels for the formation of intermediates of 3H-pyrroles are considered. The qualitative agreement of the obtained results with kinetic studies is demonstrated.
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transition metal free regioselective access to 9 10 dihydroanthracenes via the reaction of anthracenes with elemental phosphorus in the koh dmso system
Tetrahedron Letters, 2018Co-Authors: Vladimir A. Kuimov, S F Malysheva, N. K. Gusarova, B A TrofimovAbstract:Abstract Anthracene and its 9- or 9,10-substituted (Me, Ph, Cl, Br) derivatives react with red phosphorus (Pn) in the KOH/DMSO Superbase system at 85–120 °C to afford 9,10-dihydroanthracenes in good to excellent yields, thus providing simple and clean access to these extensively used dihydroaromatics.
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polycyclic bridgehead acetals with enol functionality one pot assembly from aliphatic ketones and acetylene in koh dmso suspension
Tetrahedron, 2016Co-Authors: Elena Yu. Schmidt, Igor A. Ushakov, Ivan A Bidusenko, Natalia A Cherimichkina, B A TrofimovAbstract:Abstract Aliphatic and cycloaliphatic ketones undergo selective multi-site cascade C–H functionalization with acetylene in the KOH/DMSO Superbase suspension under mild conditions (70–80 °C, 0.5–1.0 h) to afford in one synthetic operation polycyclic bridgehead acetals with enol functionality, [methylene-6,8-dioxabicyclo[3.2.1]octanes] (the isolated yields reach 84%).
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further developments in the reaction of 2 aza 1 3 5 trienes with Superbases competitive formation of new 4 5 dihydro 1 3 thiazoles dihydroazepines and azepines by tandem deprotonation cyclization
Synthesis, 2015Co-Authors: N A Nedolya, O A Tarasova, A I Albanov, B A TrofimovAbstract:Allyl- and benzylsulfanyl-substituted 2-aza-1,3,5-trienes, which are readily available from alkoxyallenes, isothiocyanates, and allyl or benzyl bromide, are easily transformed into polyfunctionalized 4,5-dihydro-1,3-thiazoles (2-thiazolines) through deprotonation of the activated SCH 2 group upon treatment with Superbase, followed by intramolecular [1,5]-ring-closing. Competitive deprotonation of the methyl group or methylene fragment of the ketimine function of the same molecule, followed by [1,7]-electrocyclization, leads to seven-membered azaheterocycles, dihydroazepines and/or azepines.
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novel general halogen free methodology for the synthesis of organophosphorus compounds
ChemInform, 2012Co-Authors: Nina K. Gusarova, S N Arbuzova, B A TrofimovAbstract:The use of novel general halogen-free methodology for the synthesis of phos- phines, phosphine chalcogenides, and phosphinic acids from elemental phosphorus and alkenes and alkynes in the Superbase suspensions is described.
Boris A. Trofimov - One of the best experts on this subject based on the ideXlab platform.
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Superbase promoted multi molecular acetylene arylamine self organization to 1 arylpyrroles
Mendeleev Communications, 2020Co-Authors: Elena Yu. Schmidt, Nadezhda V Semenova, Ivan A Bidusenko, Elena Ivanova, Boris A. TrofimovAbstract:A new Superbase-promoted reaction of acetylene involves self-organization of its three molecules with one molecule of arylamine in KOH/DMSO system to afford 1-aryl-2,5- dimethylpyrroles in up to 63% yields. The key step of this reaction cascade is assumed to be the nucleophilic addition of acetylene to the C = N bond of the intermediate aldimine (aza-Favorsky reaction).
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quantum chemical comparison of ethynylation and c vinylation routes in Superbase catalyzed reaction of acetylenes with imines
Mendeleev Communications, 2019Co-Authors: Vladimir B Orel, Elena Yu. Schmidt, N M Vitkovskaya, Damir Z Absalyamov, Boris A. TrofimovAbstract:The kinetic (free activation energies) and thermodynamic factors, which ensure mild conditions for the ethynylation of imines with acetylenes, have been established by quantum chemical calculations using B2PLYP/6-311 + G**//B3LYP/6-31 + G*. According to the calculations, the alternative route of Superbase catalyzed C-vinylation requires harsher reaction conditions as compared to the ethynylation one.
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Toward Acetylene Renaissance: Functionally Rich N‑Aminoindoles from Acetylene Gas, Ketones, and Hydrazines in Two Steps
2019Co-Authors: Elena Yu. Schmidt, Alexander V Vashchenko, Nadezhda V Semenova, Inna V Tatarinova, Igor’ A. Ushakov, Boris A. TrofimovAbstract:A straightforward acetylene-based scalable strategy for the synthesis of highly functionalized N-aminoindoles has been discovered. This pot-, atom-, step-, and energy-economic strategy includes two simple stages: (i) a one-pot multimolecular (2 + 2) diastereoselective assembly of 6,8-dioxabicyclo[3.2.1]octanes (6,8-DOBCOs) from acetylene gas and ketones in the KOH/DMSO two-phase Superbase catalytic system and (ii) a mild (rt, CF3COOH) cascade transformation of 6,8-DOBCOs under the action of hydrazines to afford N-(arylamino)-3-(acylpropyl)indoles in good yields
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acetylene as driving and organizing molecule in the assembling reactions with chalcones in the naobu t dmso Superbase system
Mendeleev Communications, 2018Co-Authors: Elena Yu. Schmidt, Ivan A Bidusenko, Natalia A Cherimichkina, Boris A. TrofimovAbstract:Acetylene reacts with chalcones in the NaOBut / DMSO Superbase system (3–12 atm, 70 °C, 15 min) to give, along with substituted furans, functionalized 3-exo-aryl-7-methylidene- 6,8-dioxabicyclo[3.2.1]octanes, novel frontalin congeners, which are diastereoselectively assembled from two molecules of chalcones and one molecule of acetylene.
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efficient switching from the 2 3 to 2 2 bipyrrole scaffold via the recyclization of 1 benzoylmethylanilino 3 imino 3h 2 cyanopyrrolizines crucial effect of the dbu organic Superbase
Tetrahedron Letters, 2017Co-Authors: Boris A. Trofimov, Elena F Sagitova, Igor A. Ushakov, Lyubov N Sobenina, O V Petrova, Boris A. Trofimov, Alexander V VashchenkoAbstract:The recyclization of readily available 1-(benzoylmethylanilino)-3-imino-3H-2-cyanopyrrolizines using the DBU organic Superbase, unexpectedly gave 2,2′-bipyrroles with amino, keto and cyano functional groups on one of the pyrrole rings in 83–94% yield. Previously, using the KOH/DMSO system, this recyclization led to 2,3′-bipyrroles in low yields (12–26%). This selective switching was explained by sterically hindered access for the intermediate carbanion to the 1-position of the pyrrolizine ring due to the large size of the accompanying DBU countercation. The new methodology opens an efficient route to pharmaceutically and synthetically useful densely functionalized 2,2′-bipyrroles.
