Ionic liquids: not always innocent solvents for cellulose

Clough, Matthew T.; Geyer, Karolin; Hunt, Patricia A.; Son, Sunghee; Vagt, Uwe; Welton, Tom

doi:10.1039/c4gc01955e

Cited by 162 publications

(133 citation statements)

References 76 publications

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“…However, less nucleophilic anions such as chloride make the IL not reactive enough with CO2. In 2015, a thorough study by Welton and coworkers (Clough et al, 2015) proved that the decomposition of carbohydrates in the presence of carboxylate based ILs, e.g. acetate, which highlights the importance of finding more benign solvents for polysaccharides.…”

Section: Introductionmentioning

confidence: 98%

An investigation of carbon dioxide capture by chitin acetate/DMSO binary system

Eftaiha

Alsoubani

Assaf

et al. 2016

Carbohydrate Polymers

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Section: Introductionmentioning

confidence: 98%

An investigation of carbon dioxide capture by chitin acetate/DMSO binary system

Eftaiha

Alsoubani

Assaf

et al. 2016

Carbohydrate Polymers

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“…Adopting this procedure,i ti sp ossible to recycle the IL for successive fractionation cycles.E ffective application of ILs towards biomass valorisation has been previously hindered by (amongst other reasons) the high costs of IL precursors and synthesis,t he derivatising nature of the IL, and difficulties regarding the separation and recycling of the IL. [256,[269][270][271] However,triethylammonium hydrogen sulfate shows production costs close to those of conventional organic solvents and can be recycled in the process. [259] Moreover,cellulosic fibres can be easily recovered by filtration as cellulose is insoluble in these ILs.…”

Section: Other Fractionation Methods Based On Acid Catalysismentioning

confidence: 99%

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

et al. 2016

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Lignin is an abundant biopolymer with a high carbon content and high aromaticity. Despite its potential as a raw material for the fuel and chemical industries, lignin remains the most poorly utilised of the lignocellulosic biopolymers. Effective valorisation of lignin requires careful fine‐tuning of multiple “upstream” (i.e., lignin bioengineering, lignin isolation and “early‐stage catalytic conversion of lignin”) and “downstream” (i.e., lignin depolymerisation and upgrading) process stages, demanding input and understanding from a broad array of scientific disciplines. This review provides a “beginning‐to‐end” analysis of the recent advances reported in lignin valorisation. Particular emphasis is placed on the improved understanding of lignin's biosynthesis and structure, differences in structure and chemical bonding between native and technical lignins, emerging catalytic valorisation strategies, and the relationships between lignin structure and catalyst performance.

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“…Distillation of the ionic liquid is one method, which has been applied to [emim] [OAc], 44 a well-known ionic liquid for dissolving cellulose, but which requires rather high temperatures and reduced pressures. This ionic liquid has also been shown to react with the cellulose substrate [45][46][47] via a reaction of the imidazolium carbene at the C2 position and the cellulose reducing end, forming a 2-(hydroxymethyl)-substituted imidazolium adduct 45 49 which are also able to dissolve cellulose. Since water is oen used as a precipitating anti-solvent, another possible recycling or purication method is phase-separation of the ionic liquid from water, if it is present.…”

Section: Introductionmentioning

confidence: 99%

Efficiency of hydrophobic phosphonium ionic liquids and DMSO as recyclable cellulose dissolution and regeneration media

et al. 2017

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Hydrophobic, long-chain tetraalkylphosphonium acetate salts (ionic liquids) were combined with a dipolar aprotic co-solvent, dimethylsulfoxide (DMSO), and the feasibility of these solvent systems for cellulose dissolution and regeneration was studied. A 60 : 40 w/w mixture of the ionic liquid tetraoctylphosphonium acetate ([P 8888 ][OAc]) and DMSO was found to dissolve up to 8 wt% cellulose, whilst trioctyl(tetradecyl)phosphonium acetate ([P 14888 ][OAc]) dissolved up to 3 wt% cellulose. Water (an anti-solvent for cellulose) was found to give rise to biphasic liquid-liquid systems when combined with these mixtures, yielding an upper phase rich in ionic liquid and a lower aqueous phase. The liquid-liquid equilibria of the ternary systems were experimentally determined, finding that DMSO strongly partitioned towards the aqueous phase. Thus, a process scheme involving simultaneous regeneration of cellulose and recycling of the solvent system was envisioned, and demonstrated on a large scale using [P 8888 ] [OAc]. A large portion of the ionic liquid (ca. 60 wt%) was directly recovered via phase separation, with a further 37 wt% being recovered from the swollen cellulose phase and residual materials, bringing recovery to 97%. XRD analysis of the recovered cellulose materials showed a loss of crystallinity and conversion from Cellulose I to Cellulose II. Non-dissolving compositions of ionic liquid and DMSO did not affect cellulose crystallinity after cellulose pulp treatment.

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Ionic liquids: not always innocent solvents for cellulose

Abstract: A comprehensive investigation into the limitations, reactivity and chemical decomposition mechanisms of ionic liquid–carbohydrate mixtures.

Cited by 162 publications

References 76 publications

An investigation of carbon dioxide capture by chitin acetate/DMSO binary system

An investigation of carbon dioxide capture by chitin acetate/DMSO binary system

Paving the Way for Lignin Valorisation: Recent Advances in Bioengineering, Biorefining and Catalysis

Efficiency of hydrophobic phosphonium ionic liquids and DMSO as recyclable cellulose dissolution and regeneration media

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