An organocatalytic ionic liquid

Kelemen, Zsolt; Hollóczki, Oldamur; Nagy, József; Nyulászi, László

doi:10.1039/c1ob05639e

Cited by 95 publications

(69 citation statements)

References 53 publications

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“…described above. This new resonance structure is likely to originate from a subsequent chemisorption between EMIMAc and CO 2 due to the ability of EMIMAc to form a carbene (Kelemen et al 2011). These findings indicate that a possible reaction takes place between the cellulose-sorbed CO 2 and the EMIM?, yielding a carboxylated EMIM ?…”

Section: Chemical Structures Of Dissolved and Regenerated Cellulosementioning

confidence: 63%

Chemisorption of air CO2 on cellulose: an overlooked feature of the cellulose/NaOH(aq) dissolution system

2017

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A natural abundance of the air CO 2 in NaOH(aq) at low temperature was investigated in terms of cellulose-CO 2 interactions upon cellulose dissolution in this system. An organic superbase, namely 1,8-diazabicyclo[5.4.0]undec-7-ene, DBU, known for its ability to incorporate CO 2 in carbohydrates, was employed in order to shed light on this previously overlooked feature of NaOH(aq) at low temperature. The chemisorption of CO 2 onto cellulose was investigated using spectroscopic methods in combination with suitable regeneration procedures. ATR-IR and NMR characterisation of regenerated celluloses showed that chemisorption of CO 2 onto cellulose during its dissolution in NaOH(aq) takes place both with and without employment of the CO 2 -capturing superbase. The chemisorption was also observed to be reversible upon addition of water: CO 2 desorbed when water was used as regenerating agent but could be preserved when instead ethanol was used. This finding could be an important parameter to take into consideration when developing processes for dissolution of cellulose based on this system.

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Section: Chemical Structures Of Dissolved and Regenerated Cellulosementioning

confidence: 63%

Chemisorption of air CO2 on cellulose: an overlooked feature of the cellulose/NaOH(aq) dissolution system

2017

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“…Kelemen and coworkers successfully used imidazolium acetate as organocatalysts for benzoin condensation, hydroacylation and oxidation of alcohols using carbon-dioxide and air [130] (see Scheme 24).…”

Section: As Organocatalystsmentioning

confidence: 99%

Ionic Liquids: Synthesis and Applications in Catalysis

Rajni

2014

Advances in Chemistry

217

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Ionic liquids have emerged as an environmentally friendly alternative to the volatile organic solvents. Being designer solvents, they can be modulated to suit the reaction conditions, therefore earning the name "task specific ionic liquids. " Though primarily used as solvents, they are now finding applications in various fields like catalysis, electrochemistry, spectroscopy, and material science to mention a few. The present review is aimed at exploring the applications of ionic liquids in catalysis as acid, base, and organocatalysts and as soluble supports for catalysts.

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“…[14][15][16][17][18][19][20][21][22][23] A reactive mechanism has been proposed in which the proton bounded to carbon atom 2 of the imidazolium cation is released leading to the generation of a carbene intermediate, whereas the proton interacts with the acetate anion to form acetic acid (Fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Understanding chemical reactions of CO2 and its isoelectronic molecules with 1-butyl-3-methylimidazolium acetate by changing the nature of the cation: The case of CS2 in 1-butyl-1-methylpyrrolidinium acetate studied by NMR spectroscopy and density functional theory calculations

Cabaço¹,

Besnard

Chávez

et al. 2014

The Journal of Chemical Physics

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NMR spectroscopy ( 1 H, 13 C, 15 N) shows that carbon disulfide reacts spontaneously with 1-butyl-1-methylpyrrolidinium acetate ([BmPyrro][Ac]) in the liquid phase. It is found that the acetate anions play an important role in conditioning chemical reactions with CS 2 leading, via coupled complex reactions, to the degradation of this molecule to form thioacetate anion (CH 3 COS − ), CO 2 , OCS, and trithiocarbonate (CS 3 2− ). In marked contrast, the cation does not lead to the formation of any adducts allowing to conclude that, at most, its role consists in assisting indirectly these reactions. The choice of the [BmPyrro] + cation in the present study allows disentangling the role of the anion and the cation in the reactions. As a consequence, the ensemble of results already reported on (2), and CO 2 - [Bmim][Ac] (3) systems can be consistently rationalized. It is argued that in system (1) both anion and cation play a role. The CS 2 reacts with the acetate anion leading to the formation of CH 3 COS − , CO 2 , and OCS. After these reactions have proceeded the nascent CO 2 and OCS interact with the cation to form imidazolium-carboxylate ([Bmim] CO 2 ) and imidazoliumthiocarboxylate ([Bmim] COS). The same scenario also applies to system (2). In contrast, in the CO 2 - [Bmim] [Ac] system a concerted cooperative process between the cation, the anion, and the CO 2 molecule takes place. A carbene issued from the cation reacts to form the [Bmim] CO 2 , whereas the proton released by the ring interacts with the anion to produce acetic acid. In all these systems, the formation of adduct resulting from the reaction between the solute molecule and the carbene species originating from the cation is expected. However, this species was only observed in systems (2) and (3). The absence of such an adduct in system (1) has been theoretically investigated using DFT calculations. The values of the energetic barrier of the reactions show that the formation of [Bmim] CS 2 is unfavoured and that the anion offers a competitive reactive channel via an oxygensulphur exchange mechanism with the solute in systems (1) and (2). © 2014 AIP Publishing LLC.

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An organocatalytic ionic liquid

Cited by 95 publications

References 53 publications

Chemisorption of air CO2 on cellulose: an overlooked feature of the cellulose/NaOH(aq) dissolution system

Chemisorption of air CO2 on cellulose: an overlooked feature of the cellulose/NaOH(aq) dissolution system

Ionic Liquids: Synthesis and Applications in Catalysis

Understanding chemical reactions of CO2 and its isoelectronic molecules with 1-butyl-3-methylimidazolium acetate by changing the nature of the cation: The case of CS2 in 1-butyl-1-methylpyrrolidinium acetate studied by NMR spectroscopy and density functional theory calculations

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