The role of cyclodextrin-tetrabutylammonium complexation on the cellulose dissolution

Medronho, Bruno; Duarte, Hugo; Alves, Luís; Antunes, Filipe E.; Romano, Anabela; Valente, Artur J.M.

doi:10.1016/j.carbpol.2015.12.026

Cited by 30 publications

(11 citation statements)

References 38 publications

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“…The complex interplay between H-bonding, ionization effects, and hydrophobic interactions is crucial to control dissolution, regeneration, gelation, and related phenomena [40]. As shown above, cellulose dissolution mechanism has been investigated in detail in recent years [10,40,70,81,[89][90][91][92][93][94][95][96][97][98][99][100][101]. Cellulose regeneration was less investigated due to the inherent difficulty of studying this phenomenon.…”

Section: Mechanism Of Regeneration Of Dissolved Cellulosementioning

confidence: 99%

Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration

et al. 2019

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This review is focused on assessment of solvents for cellulose dissolution and the mechanism of regeneration of the dissolved biopolymer. The solvents of interest are imidazole-based ionic liquids, quaternary ammonium electrolytes, salts of super-bases, and their binary mixtures with molecular solvents. We briefly discuss the mechanism of cellulose dissolution and address the strategies for assessing solvent efficiency, as inferred from its physico-chemical properties. In addition to the favorable effect of lower cellulose solution rheology, microscopic solvent/solution properties, including empirical polarity, Lewis acidity, Lewis basicity, and dipolarity/polarizability are determinants of cellulose dissolution. We discuss how these microscopic properties are calculated from the UV-Vis spectra of solvatochromic probes, and their use to explain the observed solvent efficiency order. We dwell briefly on use of other techniques, in particular NMR and theoretical calculations for the same purpose. Once dissolved, cellulose is either regenerated in different physical shapes, or derivatized under homogeneous conditions. We discuss the mechanism of, and the steps involved in cellulose regeneration, via formation of mini-sheets, association into "mini-crystals", and convergence into larger crystalline and amorphous regions. We discuss the use of different techniques, including FTIR, X-ray diffraction, and theoretical calculations to probe the forces involved in cellulose regeneration.

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Section: Mechanism Of Regeneration Of Dissolved Cellulosementioning

confidence: 99%

Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration

et al. 2019

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“…A detailed analysis of the balance of interactions by Bergenstråhle et al clearly demonstrated the same point as has also other analyses. [31][32][33] There are several observations that suggest that hydrophobic interactions are decisive for the behavior of cellulose in aqueous systems: 34 -In the structure of cellulose there is a clear segregation into polar (OH) and nonpolar (CH) patches, and thus a clear amphiphilicity. [35][36][37][38] Due to the hydrophobic properties of the glucopyranose plane, the cellulose chains can stack via hydrophobic interactions and can form a sheet-like structure ( Fig.…”

Section: Hydrogen Bonding Vs Hydrophobic Interactionsmentioning

confidence: 99%

“…Later studies by Alves et al gave strong qualitative support to the work of Isogai in two ways, namely by demonstrating large pH dependencies of NMR chemical shifts and by nonspecific electrolyte effects in decreasing cellulose solubility. [93][94][95] With self-diffusion NMR, Gentile and Olsson have shown in a strong alkaline solvent that the tetrabutylammonium cation (TBA + ) binds to cellulose with approximately 1.2 TBA + ions per glucose unit and the reason for such binding is suggested to be the electrostatic interaction with the deprotonated hydroxyl groups on cellulose combined with hydrophobic interactions. 96 For cellulose dissolution in an aqueous metal complex based system, it has been realized that the deprotonation of OH-groups (C2 and C3) is necessary before the complex can be established at those positions.…”

Section: Does Cellulose Ionization Contribute To Solubility In Water?mentioning

confidence: 99%

The relevance of structural features of cellulose and its interactions to dissolution, regeneration, gelation and plasticization phenomena

Lindman

Medronho

Alves

et al. 2017

Phys. Chem. Chem. Phys.

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196

109

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aCellulose is the most abundant polymer and a very important renewable resource. Since cellulose cannot be shaped by melting, a major route for its use for novel materials, new chemical compounds and renewable energy must go via the solution state. Investigations during several decades have led to the identification of several solvents of notably different character. The mechanisms of dissolution in terms of intermolecular interactions have been discussed from early work but, even on fundamental aspects, conflicting and opposite views appear. In view of this, strategies for developing new solvent systems for various applications have remained obscure. There is for example a strong need for using forest products for higher value materials and for environmental and cost reasons to use water-based solvents. Several new water-based solvents have been developed recently but there is no consensus regarding the underlying mechanisms. Here we wish to address the most important mechanisms described in the literature and confront them with experimental observations. A broadened view is helpful for improving the current picture and thus cellulose derivatives and phenomena such as fiber dissolution, swelling, regeneration, plasticization and dispersion are considered. In addition to the matter of hydrogen bonding versus hydrophobic interactions, the role of ionization as well as some applications of new knowledge gained are highlighted.

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“…In fact, several theoretical and experimental studies have validated that tetraalkylammonium cations and amino acids are able to form van der waals interactions or strong hydrogen bonds with CDs . In the “α‐CD/AAILs/enantiomers” ternary system, enantiomers tended to occupy the hydrophobic cavity of α‐CD; however, the formed inclusion complex was not stable because of the unsuitable cavity size.…”

Section: Resultsmentioning

confidence: 99%

Enhanced enantioselectivity of native α‐cyclodextrins by the synergy of chiral ionic liquids in capillary electrophoresis

Zhang

Xue

et al. 2018

J of Separation Science

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In the cyclodextrins family, the native α‐cyclodextrin has almost been abandoned in capillary electrophoresis chiral separation due to its much weaker enantioselectivity compared with β‐cyclodextrin and their derivatives. In this work, several amino acid chiral ionic liquids were selected to establish synergistic enantioseparation systems with native α‐cyclodextrin. Enhanced enantioselectivities were observed in the chiral ionic liquids/α‐cyclodextrin synergistic systems compared with single α‐cyclodextrin system. A series of comparison experiments were performed to demonstrate the superiority of the synergistic systems. Primary parameters affecting the enantioseparation were systematically optimized, including the type and concentration of chiral ionic liquids, α‐cyclodextrin concentration, buffer pH, and applied voltage. Best separations of the model enantiomers were obtained in a 20 mM Tris/H3PO4 buffer at pH 2.5 containing 3% (m/v) α‐cyclodextrin and 30 mM tetramethylammonium‐l‐arginine. The results show that the α‐cyclodextrin is also worth our attention when selecting chiral selectors for capillary electrophoresis enantioseparation of specific racemic compound.

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The role of cyclodextrin-tetrabutylammonium complexation on the cellulose dissolution

Cited by 30 publications

References 38 publications

Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration

Cellulose in Ionic Liquids and Alkaline Solutions: Advances in the Mechanisms of Biopolymer Dissolution and Regeneration

The relevance of structural features of cellulose and its interactions to dissolution, regeneration, gelation and plasticization phenomena

Enhanced enantioselectivity of native α‐cyclodextrins by the synergy of chiral ionic liquids in capillary electrophoresis

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