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

Kostag, Marc; Jedvert, Kerstin; Achtel, Christian; Heinze, Thomas; Seoud, Omar A. El

doi:10.3390/molecules23030511

Cited by 62 publications

(51 citation statements)

References 217 publications

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“…Below, we focus our discussion of these issues on ionic liquids (ILs), and two of their sub-classes: quaternary ammonium electrolytes (QAEs), and salts of super-bases. Additional discussion on aspects of dissolution of cellulose and other natural polymers in ILs and applications of the solutions obtained therefrom can be found elsewhere [7][8][9][10][11][12][13][14][15][16][17].…”

Section: Ionic Liquids Quaternary Ammonium Electrolytes and Salts Omentioning

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: Ionic Liquids Quaternary Ammonium Electrolytes and Salts Omentioning

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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“…Solubility of cellulose in imidazolium‐based ILs has been covered in review articles and book chapters. [ 7,110,111 ] As discussed above, the choice of cation and anion affects cellulose dissolution and bears on environmental aspects and sustainability of the process. [ 112 ] Common imidazolium‐based ILs, such as BuMeImCl, 1‐ethyl‐3‐methylimidazolium chloride and 1‐ethyl‐3‐methylimidazolium acetate were compared with NMMO as spin dopes for shaping cellulose into fibers.…”

Section: Regeneration Of Cellulose In Different Physical Formsmentioning

confidence: 99%

“…Other ILs, such as QAEs, were recently explored as solvents for regeneration of cellulose into fibers. [ 7 ] For fiber spinning, solvents based on mixtures of tetra( n ‐butyl)ammonium acetate (Bu 4 AOAc) in combination with DMSO have shown some promise. Thus, 5 wt% bamboo pulp dissolved in Bu 4 AOAc/DMSO (1:4 mass ratio) was regenerated as fibers via wet spinning, using ethanol as coagulation medium.…”

Section: Regeneration Of Cellulose In Different Physical Formsmentioning

confidence: 99%

Cellulose Regeneration and Chemical Recycling: Closing the “Cellulose Gap” Using Environmentally Benign Solvents

Seoud

Kostag

Jedvert

et al. 2020

Macro Materials & Eng

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matched by synthetic fibers. Therefore, the demand on natural and fabricated cellulosic fibers is expected to continue and rise. The production of cotton, however, is not expected to meet this demand because of restrictions on farmland use and availability of irrigation water. [3] Anticipating the so-called "the cellulosic fiber gap," [1] the textile industry currently leads several initiatives for developing fibers that can complement cotton. [3] Consequently, there is incitement and opportunities for an increase in use of cellulose from other sources, in particular wood, and increased interest in physical (i.e., mechanical) and chemical recycling (CR) of biopolymers. [4] Production of fibers and other artifacts from cellulose extracted from wood involves chemical or physical dissolution of the biopolymer, followed by its regeneration in the desired physical form in an appropriate bath. The most important example of cellulose chemical dissolution (i.e., via covalent bond formation) is the viscose rayon fiber, produced by regeneration of cellulose from its xanthate in acid bath. The Lyocell fiber process involves, however, physical dissolution of cellulose in N-methylmorpholine-N-oxide (NMMO) hydrate, followed by regeneration in an aqueous bath. [5] Cellulose regeneration is not restricted to formation of fibers. The biopolymer and its derivatives, in particular esters, can be "shaped" into other physical forms including spheres of different diameters (down to the nanoscale), films produced by casting and spin coating, and nonwoven mats produced by electrospinning or solution blowing. This review covers some recent advances of the regeneration of cellulose from alkali solutions and ionic solvents, in particular those based on imidazole, quaternary ammonium electrolytes (QAEs), and salts of heterocyclic super-bases. We refer to these ionic solvents collectively as ionic liquids (ILs). Representative examples of the ILs employed for cellulose dissolution are shown in Figure 1. These solvents dissolve cellulose samples of a wide range of degrees of polymerization (DPs) and indices of crystallinity (Ics). For practical reasons, binary mixtures of ILs with molecular solvents (MSs) are used alongside pure ILs. This use is advantageous because of the concomitant decrease in solution viscosity; there are many examples where the binary solvent mixture dissolves more cellulose than the parent pure IL. [5] Strategies to mitigate the expected "cellulose gap" include increased use of wood cellulose, fabric reuse, and recycling. Ionic liquids (ILs) are employed for cellulose physical dissolution and shaping in different forms. This review focuses on the regeneration of dissolved cellulose as nanoparticles, membranes, nonwoven materials, and fibers. The solvents employed in these applications include ILs and alkali solutions without and with additives. Cellulose fibers obtained via the carbonate and carbamate processes are included. Chemical recycling (CR) of polycotton (cellulose plus poly(ethylene terephthalate)) is addressed...

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“…[24] Indeed, the high ionic strength of the ILs allows interrupting the inter-and intramolecular hydrogen-bondingbased interactions in cellulose chains. [24][25][26] Some studies with ILs outline that the nature of the anion is responsible for the dissolution of cellulose. However, it was also shown that especially the structure of the cation influences the solvation process, too.…”

Section: Introductionmentioning

confidence: 99%

Processing of Cellulose Using Ionic Liquids

Hermanutz

Vocht

Panzier

et al. 2018

Macro Materials & Eng

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The processing of cellulose dissolved in ionic liquids (ILs) enables the development of new materials. Besides the established production of cellulosic fiber products, interesting technical applications are developed like super micro filament fibers, cellulose/chitin blend fibers, precursors for carbon fibers, and all‐cellulose composites. This review provides a detailed summary of these new developments and describes how ILs are selected for the processing of cellulose with a particular emphasis on industrial realization. State‐of‐the‐art spinning processes are reviewed and it is illustrated how uniquely selected ILs can be used not only for established fiber spinning but for the development of new cellulose‐based materials.

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

Cited by 62 publications

References 217 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

Cellulose Regeneration and Chemical Recycling: Closing the “Cellulose Gap” Using Environmentally Benign Solvents

Processing of Cellulose Using Ionic Liquids

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