Feasibility of thermal separation in recycling of the distillable ionic liquid [DBNH][OAc] in cellulose fiber production

Ahmad, Waqar; Ostonen, Alexandr; Jakobsson, Kaj; Uusi–Kyyny, Petri; Alopaeus, Ville; Hyväkkö, Uula; King, Alistair W. T.

doi:10.1016/j.cherd.2016.08.032

Cited by 26 publications

(30 citation statements)

References 16 publications

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“…This is possible through distillation of the recovered ionic liquid (King et al 2011). Recent results have indicated that DBN actually has a higher vapor pressure than acetic acid in the mixture, allowing for partial separation of the components (Ahmad et al 2016). Thus, the motivation for this method is sound.…”

Section: Resultsmentioning

confidence: 99%

Homogenous esterification of cellulose pulp in [DBNH][OAc]

2017

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Cellulose acetate is widely used in films, filters, textiles, lacquer and cosmetic products. Herein we demonstrate the production of cellulose esters under homogeneous conditions using 1,5-diazabicyclo[4.3.0]non-5-ene acetate ([DBNH][OAc]) as solvent. The reagents have been chosen such that the system is recyclable, i.e. by-products are low boiling and easy to remove. It is demonstrated that cellulose acetate can be synthesized with different degree of substitution (DS) values, and that some commonly used acylation regents, like vinyl carboxylates react well without additional base catalyst. Low to high DS values are possible with good recovery of high purity ionic liquid (IL). A linear correlation method of two separate methods, IR and 31 P NMR, is proposed to reliably assess the DS of the products. The recyclability of the solvent is demonstrated by acetylating cellulose with isopropenyl acetate to high degree and regeneration into water. After regeneration of cellulose acetate from the IL with addition of water, the residual water was entrained using n-butanol to minimize hydrolysis of [DBNH][OAc], to allow for high recovery and high purity of the ionic liquid. Thus, an overall scheme for batch cellulose acetylation and recovery of [DBNH][OAc] from aqueous solutions is proposed.

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Section: Resultsmentioning

confidence: 99%

Homogenous esterification of cellulose pulp in [DBNH][OAc]

2017

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“…Separation of ILs and low boiling point compounds by conventional distillation could be achieved in a rotary evaporator 27, 57,58,[78][79][80][81] or a thin lm evaporator. [82][83][84][85] The rotary evaporator works on the basis of reducing the pressure above a bulk liquid thus lowering the boiling points of components in the liquid mixture. Compared to the standard organic distillation glassware, the heating surface in rotary evaporator is enlarged due to the formation of a thin lm of warm solvent, which is caused by the centrifugal force and the frictional force between the wall of the rotating ask and the liquid sample.…”

Section: Distillationmentioning

confidence: 99%

“…The aqueous two-phase extraction, which is based on the formation of aqueous two-phase systems with no use of organic solvents, is regarded as an environmentally friendly method to recover hydrophilic ILs from aqueous solutions. Adding inorganic salts or carbohydrates could induce the phase separation of water and a variety of ILs (e.g., [C 4 Comparison of ionic liquids recovery methods 3 27, 81,84,85 Distillation through reaction of ILs ) and amines, the ATPS could be formed upon the introduction of CO 2 at ambient conditions. For aqueous solution of ILs prepared from amino acids (e.g., [P 4444 ][Tf-Leu]), the ILs could be separated directly from water when CO 2 is bubbled.…”

Section: Mim][pf 6 ]mentioning

confidence: 99%

Recovery and purification of ionic liquids from solutions: a review

et al. 2018

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“…Nevertheless, under certain conditions, several organic compounds and green solvents, such as ionic liquids and deep eutectic solvents, can undergo thermal degradation or hydrolysis [2][3][4][5][6]. Even though it has been reported that low-pressure evaporation and distillation [7][8][9] can be used as a concentration method in the recycling of ionic liquids from aqueous ionic liquid solutions, the main drawback of such processes is that they are high-energy separation methods due to the high latent heat of evaporation. Consequently, there is a need to find more feasible concentration methods, which also allow application at low-temperature ranges.…”

Section: Introductionmentioning

confidence: 99%

Freeze Concentration of Aqueous [DBNH][OAc] Ionic Liquid Solution

et al. 2020

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In the present work, freeze crystallization studies, as a novel concentration method for aqueous 1,5-diazabicyclo[4.3.0]non-5-enium acetate ([DBNH][OAc]) ionic liquid solution, were conducted. In order to find the appropriate temperature and composition range for freeze crystallization, the solid–liquid equilibrium of a binary [DBNH][OAc]–water compound system was investigated with differential scanning calorimetry (DSC). Results of this analysis showed that the melting temperature of the pure ionic liquid was 58 ℃, whereas the eutectic temperature of the binary compound system was found to be −73 ℃. The activity coefficient of water was determined based on the freezing point depression data obtained in this study. In this study, the lowest freezing point was −1.28 ℃ for the aqueous 6 wt.% [DBNH][OAc] solution. Ice crystal yield and distribution coefficient were obtained for two types of aqueous solutions (3 wt.% and 6 wt.% [DBNH][OAc]), and two freezing times (40 min and 60 min) were used as the main parameters to compare the two melt crystallization methods: static layer freeze and suspension freeze crystallization. Single-step suspension freeze crystallization resulted in higher ice crystal yields and higher ice purities when compared with the single-step static layer freeze crystallization. The distribution coefficient values obtained showed that the impurity ratios in ice and in the initial solution for suspension freeze crystallization were between 0.11 and 0.36, whereas for static layer freeze crystallization these were between 0.28 and 0.46. Consequently, suspension freeze crystallization is a more efficient low-energy separation method than layer freeze crystallization for the aqueous-ionic liquid solutions studied and, therefore, this technique can be applied as a concentration method for aqueous-ionic liquid solutions.

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Feasibility of thermal separation in recycling of the distillable ionic liquid [DBNH][OAc] in cellulose fiber production

Cited by 26 publications

References 16 publications

Homogenous esterification of cellulose pulp in [DBNH][OAc]

Homogenous esterification of cellulose pulp in [DBNH][OAc]

Recovery and purification of ionic liquids from solutions: a review

Freeze Concentration of Aqueous [DBNH][OAc] Ionic Liquid Solution

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