Thermodynamic analysis of cellulose complex in NaOH–urea solution using reference interaction site model

Huh, Eugene; Yang, Ji Hyun; Lee, Chang Ha; Ahn, Ik Sung; Mhin, Byung Jin

doi:10.1007/s10570-020-03202-w

Cited by 7 publications

(13 citation statements)

References 38 publications

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“…The was found to be in the order urea >> LiOH > Water > NaOH > KOH. seems to be constant regardless of the other solvent species, such as MOHs, which corresponds well with the positioning of urea above and below the pyranose rings of cellulose and its interaction with cellulose independent of MOH (Huh et al 2020;Wernersson et al 2015;Xiong et al 2013). was found to be in the order LiOH > NaOH > KOH regardless of whether urea was present in the solvent.…”

Section: Resultssupporting

confidence: 61%

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RISM-Assisted Analysis of the Role of Alkali Metal Hydroxides in the Solvation of Cellulose in Alkali/urea Aqueous Solutions

Huh

Yang

Lee

et al. 2021

Preprint

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The three-dimensional reference interaction site model theory with the Kovalenko-Hirata closure (3D-RISM-KH) combined with the Kirkwood-Buff integral (KBI) was used to clarify the role of alkali metal hydroxides (MOHs) in cellulose solvation in alkali/urea aqueous solutions. The KBI and excess number of MOHs showed that their access and affinity to cellulose were both in the order LiOH > NaOH > KOH. The cavity and interaction volumes for cellulose indicate that the alkali metal ions closer in proximity to cellulose induce thermal fluctuations of cellulose molecules more easily and cause more electrostatic interactions and hydrogen bonding with cellulose. These calculation results support the hypothesis of cellulose charging up, which claims that cellulose-ion interactions cause cellulose solvation. The energy and chemical potential of cellulose solvation confirmed the affinity and interaction of MOHs with cellulose. Solvent reorganization, whose energy primarily determined the solvation energy, was found to be facilitated by the more proximal MOH when in the presence of urea. 3D-RISM-KH combined with KBI produced quantitative information regarding the distribution and attractive interaction of MOHs (especially LiOH) with cellulose, which clarified their role in cellulose solvation in alkali/urea aqueous solutions.

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Section: Resultssupporting

confidence: 61%

“…In our previous work (Huh et al 2020), the three-dimensional reference interaction site model theory with the Kovalenko-Hirata closure (3D-RISM-KH) was applied to calculate the solvation energy of cellulose in NaOH/urea aqueous solution at 261 K and to determine the contribution of each solvent species (i.e.,…”

Section: Introductionmentioning

confidence: 99%

RISM-Assisted Analysis of the Role of Alkali Metal Hydroxides in the Solvation of Cellulose in Alkali/urea Aqueous Solutions

Huh

Yang

Lee

et al. 2021

Preprint

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“…Cellulose dissolution is a prerequisite for manufacturing valueadded cellulosic products, such as regenerated fibers, filaments and films (Wawro et al 2009;Yang et al 2011a), and producing functional cellulose-based materials in a homogenous environment (Gericke et al 2013;Wang et al 2016). Functionalizing cellulose in the dissolved state is desired due to the full availability of hydroxyl (OH) groups, control of both the degree of substitution (DS) and the distribution of the functional groups as well as minimal chain degradation and high yield due to small consumption of reagent by side reactions (Heinze et al 2000). Yet, as the load-bearing structure in nature, cellulose is a recalcitrant polysaccharide organized in the plant cell wall in a hierarchical structure that resists degradation.…”

Section: Introductionmentioning

confidence: 99%

“…Aqueous sodium hydroxide solution is a promising choice for cellulose dissolution due to the rapid, nontoxic, low cost and environmentally friendly dissolution process. The process for dissolving cellulose in aqueous NaOH was discovered already in the early 1900s (Davidson 1934(Davidson , 1936 and it is still attracting a lot of interest (Cai et al 2008;Egal et al 2007;Hagman et al 2017;Huh et al 2020;Medronho and Lindman 2015). Cellulose dissolves rapidly in aqueous NaOH, however, the dissolution is limited to low temperatures (\ 0°C), moderately low degree of polymerization (DP), low concentration of cellulose and narrow concentration range of NaOH (7-10%) (Budtova and Navard 2016;Cai et al 2008;Egal et al 2007;Hagman et al 2017;Isogai and Atalla 1998;Medronho and Lindman 2015).…”

Section: Introductionmentioning

confidence: 99%

Cellulose dissolution in aqueous NaOH–ZnO: cellulose reactivity and the role of ZnO

et al. 2021

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Cellulose utilization at its full potential often requires its dissolution which is challenging. Aqueous NaOH is the solvent of choice due to the rapid, non-toxic, low cost and environmentally friendly dissolution process. However, there are several limitations, such as the required low temperature and cellulose´s moderately low degree of polymerization and concentration. Moreover, there is a tendency for gelation of semidilute solutions with time and temperature. The addition of ZnO aids cellulose dissolution and hinders self-aggregation in the NaOH solution; however, the exact role of ZnO has remained as an open question. In this work, we studied cellulose dissolution in the aqueous NaOH–ZnO system as well as the reactivity of the dissolved cellulose by oxidation with 4-AcNH-TEMPO+ (TEMPO+). Based on Raman spectroscopic studies and the TEMPO+-reactivities, we propose a new structure for cellulose dissolved in aqueous NaOH–ZnO. Graphic abstract

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“…Cellulose dissolution with aqueous sodium hydroxide (NaOH) has a strong industrial potential due to the rapid, non-toxic, low cost and environmentally friendly process. The process has been known already since the early 1900s (Davidson 1934(Davidson , 1936 and it continues attracting a lot of interest (Cai et al 2008;Egal et al 2007;Hagman et al 2017;Huh et al 2020;Kihlman et al 2012;Medronho and Lindman 2015). The dissolution takes place at low temperature (\ 0°C) and hence there is no evaporation of chemicals during the process.…”

Section: Introductionmentioning

confidence: 99%

Cellulose dissolution in aqueous NaOH–ZnO: effect of pulp pretreatment at macro and molecular levels

et al. 2021

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This paper discusses the effect of hydrolytic pretreatments on pulp dissolution in the aqueous NaOH–ZnO solvent system. Eight samples were studied. They consisted of a never-dried softwood kraft pulp that was hydrolyzed under seven different conditions as well as the pulp without hydrolysis as a reference. The dissolution of the pulps was evaluated both at the macro level as well as at the molecular level based on their reactivity with 4-acetamido-2,2,6,6-tetramethylpiperidine-1-oxo-piperidium (4-AcNH-TEMPO+). The fiber properties (i.e. the extent of fibrillation, amount of fines and fiber width, coarseness, and length) as well as the chemical composition (hemicellulose and cellulose contents) and the viscosity of the pulps was investigated. The results show that hydrolysis at medium consistency (10%) was successful in increasing the solubility of cellulose. Hydrolysis at high consistency (50%), on the other hand, increased the solubility only to some extent. With extended treatment time the fibers formed aggregates and their dissolution became poor. This phenomenon could be overcome by mechanically refining the fibers after the hydrolysis. Moreover, comparison of the viscosity of the pulp over the degree of oxidation revealed that the viscosity needed to decrease below ca. 400 ml/g in order for the outer layers of the fibers to dissolve. Finally, when pulps with similar viscosities where compared against each other, the ones with the higher glucomannan contents formed gels over time. This was true also for the pulp with the lowest viscosity and the highest solubility of the studied samples.

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Thermodynamic analysis of cellulose complex in NaOH–urea solution using reference interaction site model

Cited by 7 publications

References 38 publications

RISM-Assisted Analysis of the Role of Alkali Metal Hydroxides in the Solvation of Cellulose in Alkali/urea Aqueous Solutions

RISM-Assisted Analysis of the Role of Alkali Metal Hydroxides in the Solvation of Cellulose in Alkali/urea Aqueous Solutions

Cellulose dissolution in aqueous NaOH–ZnO: cellulose reactivity and the role of ZnO

Cellulose dissolution in aqueous NaOH–ZnO: effect of pulp pretreatment at macro and molecular levels

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