Solvation by aqueous solutions of imidazole-based ionic liquids: 2- A comparison between alkyl and alkoxy side-chains

Jesus, Jéssica Carol de; Pires, Paulo Augusto Rodrigues; Scharf, Magdalena M.; Seoud, Omar A. El

doi:10.1016/j.fluid.2017.08.004

Cited by 6 publications

(4 citation statements)

References 40 publications

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“…The 60 vol % [EG 3 mim][Tf 2 N] gel has a CO 2 permeability of 380 barrer, which is lower than that of the 60 vol % [EGmim][Tf 2 N] (460 barrer). This was because the ether oxygen on the alkoxy tail of the IL can interact with the C-2 hydrogen from another imidazolium cation core, made possible by the separation of charges afforded by the long alkoxy chain. − This head-to-tail cation–cation interaction reduces the overall free volume of these ILs, and in this case, the effect is significant enough to reduce the gas diffusivity, as is evidenced by the lower N 2 permeability of 60 vol % [EG 3 mim][Tf 2 N] versus [EGmim][Tf 2 N] gels, where the IL–IL interaction becomes competitive with the IL–PEO interaction. Hence, having a long alkoxy tail on the IL cation appeared to be detrimental to the ion gel performance as the IL loading is increased.…”

Section: Discussionmentioning

confidence: 99%

Cross-Linked Poly(ethylene oxide) Ion Gels Containing Functionalized Imidazolium Ionic Liquids as Carbon Dioxide Separation Membranes

Kusuma

Macala

Baker

et al. 2018

Ind. Eng. Chem. Res.

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d i m i d a z o l i u m b i s -(trifluoromethylsulfonyl)imide (Tf 2 N) ionic liquids (ILs) were incorporated at 40 and 60 vol % loading into a crosslinked poly(ethylene oxide) polymer network to create ion gels for carbon dioxide (CO 2 )-selective gas separation membranes. The ILs plasticize the poly(ethylene oxide)-based polymer to increase its gas permeability. Compared to the base polymer, with a CO 2 permeability of 145 barrer and a CO 2 against nitrogen (N 2 ) selectivity of 47, the highest CO 2 permeability achieved was 530 barrer coupled with a CO 2 /N 2 selectivity of 31 by having 60 vol % [1-ethyl-3-methylimidazolium][Tf 2 N]. The extent of gas permeability improvement depends on the cation's terminal substituent. Substituents that promote additional noncovalent intermolecular interactions, such as hydroxyl, benzyl, and nitrile, can reduce the gas diffusivity by reducing the polymer chain mobility. While n-alkyl, branched alkyl, and oligo(ethylene glycol) substituents can significantly increase the gas permeability, the shortest substituents (such as ethyl) were the most effective because they promote high ionic charge density.

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Section: Discussionmentioning

confidence: 99%

Cross-Linked Poly(ethylene oxide) Ion Gels Containing Functionalized Imidazolium Ionic Liquids as Carbon Dioxide Separation Membranes

Kusuma

Macala

Baker

et al. 2018

Ind. Eng. Chem. Res.

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“…Figure 7a shows dependence of (SB-SA) on for both ILs (Figure 7b will be discussed later). The values of (SB-SA) are almost constant in the range 0.0-0.8 for the two ILs examined, due to a preferential solvation of solvatochromic probes by a component of each medium de Jesus, Pires, Scharf, & El Seoud, 2017). Therefore, the maximum dissolution of cellulose at = 0.6 ( Figure 5a) cannot be explained solely on the bases of (SB-SA).…”

Section: Assessment Of Hydrogen Bonding By 1 H and 13 C Nmrmentioning

confidence: 92%

“…Effects of "blocking" position 2 of the imidazolium ring on cellulose dissolution and derivatization Our recent work on solvatochromism in aqueous solutions of these ILs indicated the following order for empirical polarity: aqueous C4MeImAc > aqueous C3OMeImAc. This order was inverted, however, when the IL was based on 1,2-dimethylimidazole, i.e., the order of empirical polarity was: aqueous C3OMe2ImAc > aqueous C4Me2ImAc (de Jesus, Pires, Scharf, et al, 2017).…”

Section: Assessment Of Hydrogen Bonding By 1 H and 13 C Nmrmentioning

confidence: 99%

Binary mixtures of ionic liquids-DMSO as solvents for the dissolution and derivatization of cellulose: Effects of alkyl and alkoxy side chains

Ferreira

Oliveira

Bioni

et al. 2019

Carbohydrate Polymers

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The efficiency of mixtures of ionic liquids (ILs) and molecular solvents in cellulose dissolution and derivatization depends on the structures of both components. We investigated the ILs 1-(1butyl)-3-methylimidazolium acetate (C4MeImAc) and 1-(2-methoxyethyl)-3-methylimidazolium acetate (C3OMeImAc) and their solutions in dimethyl sulfoxide, DMSO, to assess the effect of presence of an ether linkage in the IL side-chain. Surprisingly, C4MeImAc-DMSO was more efficient than C3OMeImAc-DMSO for the dissolution and acylation of cellulose. We investigated both solvents using rheology, NMR spectroscopy, and solvatochromism. Mixtures of C3OMeImAc-DMSO are more viscous, less basic, and form weaker hydrogen bonds with cellobiose than C4MeImAc-DMSO. We attribute the lower efficiency of C3OMeImAc to "deactivation" of the ether oxygen and C2-H of the imidazolium ring due to intramolecular hydrogen bonding. Using the corresponding ILs with C2-CH3 instead of C2-H, namely, 1-butyl-2,3dimethylimidazolium acetate (C4Me2ImAc) and 1-(2-methoxyethyl)-2,3-dimethylimidazolium acetate (C3OMe2ImAc) increased the concentration of dissolved cellulose; without noticeable effect on biopolymer reactivity.

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“…Exchange of the halide anions with, e.g., carboxylates is carried out with anion exchange resins (usually macroporous), via the sequence shown in path II of Scheme 1 (halide → hydroxide → carboxylate). We found that direct anion exchange (halide → carboxylate) is complete, e.g., for chloride → acetate [ 70 ]. For efficient methylation or ethylation of amines the use of alkyl carbonates is possible ( Scheme 1 , path III ) [ 71 ]; the resulting carbonate is converted into other anions by reaction with the appropriate acid.…”

Section: General Synthesis Strategies For Quaternary Ammonium Elecmentioning

confidence: 99%

Recent Advances in Solvents for the Dissolution, Shaping and Derivatization of Cellulose: Quaternary Ammonium Electrolytes and their Solutions in Water and Molecular Solvents

et al. 2018

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There is a sustained interest in developing solvents for physically dissolving cellulose, i.e., without covalent bond formation. The use of ionic liquids, ILs, has generated much interest because of their structural versatility that results in efficiency as cellulose solvents. Despite some limitations, imidazole-based ILs have received most of the scientific community’s attention. The objective of the present review is to show the advantages of using quaternary ammonium electrolytes, QAEs, including salts of super bases, as solvents for cellulose dissolution, shaping, and derivatization, and as a result, increase the interest in further investigation of these important solvents. QAEs share with ILs structural versatility; many are liquids at room temperature or are soluble in water and molecular solvents (MSs), in particular dimethyl sulfoxide. In this review we first give a historical background on the use of QAEs in cellulose chemistry, and then discuss the common, relatively simple strategies for their synthesis. We discuss the mechanism of cellulose dissolution by QAEs, neat or as solutions in MSs and water, with emphasis on the relevance to cellulose dissolution efficiency of the charge and structure of the cation and. We then discuss the use of cellulose solutions in these solvents for its derivatization under homogeneous and heterogeneous conditions. The products of interest are cellulose esters and ethers; our emphasis is on the role of solvent and possible side reactions. The final part is concerned with the use of cellulose dopes in these solvents for its shaping as fibers, a field with potential commercial application.

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Solvation by aqueous solutions of imidazole-based ionic liquids: 2- A comparison between alkyl and alkoxy side-chains

Cited by 6 publications

References 40 publications

Cross-Linked Poly(ethylene oxide) Ion Gels Containing Functionalized Imidazolium Ionic Liquids as Carbon Dioxide Separation Membranes

Cross-Linked Poly(ethylene oxide) Ion Gels Containing Functionalized Imidazolium Ionic Liquids as Carbon Dioxide Separation Membranes

Binary mixtures of ionic liquids-DMSO as solvents for the dissolution and derivatization of cellulose: Effects of alkyl and alkoxy side chains

Recent Advances in Solvents for the Dissolution, Shaping and Derivatization of Cellulose: Quaternary Ammonium Electrolytes and their Solutions in Water and Molecular Solvents

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