Hydrophobic and low-density amino acid ionic liquids

Kagimoto, Junko; Taguchi, Satomi; Fukumoto, Ken-ichi; Ohno, Hiroyuki

doi:10.1016/j.molliq.2010.02.002

Cited by 86 publications

(66 citation statements)

References 46 publications

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“…Both ionic liquids were found to be immiscible with water, a property typical of long chain phosphonium ionic liquids. 50,[52][53][54] However, the pure ionic liquids prepared in this study did not dissolve cellulose to any appreciable degree, below a lower tested limit of 0.5 wt%, which ts to our previous understanding 40 of some phosphonium acetate ionic liquids (including the ionic liquid [P 8881 ][OAc]) and cellulose dissolution. Thus, we set out to use a molecular co-solvent in conjunction with these ionic liquids to enable cellulose dissolution, as we previously showed this combination to enable some non cellulose-dissolving ionic liquids to dissolve cellulose.…”

Section: Resultssupporting

confidence: 60%

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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Section: Resultssupporting

confidence: 60%

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

et al. 2017

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“…The zwitterionic amino acids allows their use as either cation or anion that facilitates multitudes of combinations for ILs. [16][17][18][19] AAILs have been employed as chiral solvents or reactants for dissolution and stabilization of cellulose, nucleic acids, carbohydrates and other species of primary biological importance. [20][21][22][23][24][25] On the theoretical front, molecular dynamics (MD) simulations on the ILs composed of deprotonated amino acid anions and choline cation revealed that their formation is facilitated through proton transfer involving the hydrogen bond effectively neutralizing cation and anion.…”

Section: Introductionmentioning

confidence: 99%

Electronic Structure, NMR, Spin–Spin Coupling, and Noncovalent Interactions in Aromatic Amino Acid Based Ionic Liquids

Rao

Gejji

2016

J. Phys. Chem. A

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Noncovalent interactions accompanying phenylalanine (Phe), tryptophan (Trp), and tyrosine (Tyr) amino acids based ionic liquids (AAILs) composed of 1-methyl-3-butyl-imidazole and its methyl-substituted derivative as cations have been analyzed employing the dispersion corrected density functional theory. It has been shown that cation-anion binding in these bioionic ILs is primarily facilitated through hydrogen bonding in addition to lp---π and CH---π interactions those arising from aromatic moieties which can be probed through (1)H and (13)C NMR spectra calculated from the gauge independent atomic orbital method. Characteristic NMR spin-spin coupling constants across hydrogen bonds of ion pair structures viz., Fermi contact, spin-orbit and spin-dipole terms show strong dependence on mutual orientation of cation with the amino acid anion. The spin-spin coupling mechanism transmits spin polarization via electric field effect originating from lp---π interactions whereas the electron delocalization from lone pair on the carbonyl oxygen to antibonding C-H orbital is facilitated by hydrogen bonding. It has been demonstrated that indirect spin-spin coupling constants across the hydrogen bonds correlate linearly with hydrogen bond distances. The binding energies and dissected nucleus independent chemical shifts (NICS) document mutual reduction of aromaticity of hydrogen bonded ion pairs consequent to localization of π-character. Moreover the nature and type of such noncovalent interactions governing the in-plane and out-of-plane NICS components provide a measure of diatropic and paratropic currents for the aromatic rings of varying size in AAILs. Besides the direction of frequency shifts of characteristic C═O and NH stretching vibrations in the calculated vibrational spectra has been rationalized.

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“…Smiglak and co-workers investigated the flammability of 20 imidazolium and phosphonium ILs and found that while ILs are not flammable themselves, they are not necessarily safe to use near fire and other sources of heat because solute impurities and the products of thermal decomposition are sensitive to composition [46,47]. This is especially true when F, Cl, P, S, C, H, N, and O in ammonium, imidazolium, pyridinium, tetrazolium, and aminotetrazole cations are paired with anions such as [NO 3 À [32,48,49]. Despite the vapor pressure and flammability issues associated with some of the ILs discussed, ILs are unquestionably classified as green solvents when compared to the VOCs currently in use by the chemical and nuclear industries [14].…”

Section: Volatility Thermal Stability and Flammabilitymentioning

confidence: 99%

“…The van der Waals interactions between alkyl chains on cationic species can be used to modulate the viscosity of ILs [49][50][51]. For example, it has been reported that the viscosity of imidazolium ILs can be increased by increasing the length of the alkyl chain on the imidazolium cation due to the increased van der Waals interactions [49][50][51]. Likewise, the anionic species can be used to modulate the viscosity of an IL by altering their relative basicity and ability to participate in hydrogen bonding [52].…”

Section: Viscositymentioning

confidence: 99%

Separating Rare-Earth Elements with Ionic Liquids

Mehio

Luo

Do‐Thanh

et al. 2016

Green Chemistry and Sustainable Technology

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The rare-earth elements (REEs) are a group of 17 chemically similar metallic elements; this group consists of scandium, yttrium, and 15 lanthanides. Due to their essential role in permanent magnets, lamp phosphors, catalysts, and rechargeable batteries, the REEs have become an essential component of the global transition to a green economy. Currently, with China producing over 90 % of the global REE output and its increasingly tightening export quota, the rest of the world is confronted with the potential risk of REE shortage. As such, many countries will have to rely on recycling REEs from pre-consumer scrap, industrial residues, and REE-containing end-of-life products. Over the course of the last two decades, ionic liquids have been increasingly used to separate REEs in the recycling process. Ionic liquids (ILs) are a class of molten salts that are liquid at temperatures below 100 C. ILs are amenable to the recycling of REEs because the cation and anion components are readily tailored to a given process, and they offer numerous advantages over typical organic solvents, such as low volatility, low flammability, a broad temperature range of stability, the ability to dissolve both inorganic and organic compounds, high conductivity, and wide electrochemical windows. In this chapter, we discuss the performance of several IL-based extraction systems used to separate and recycle REEs.

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Hydrophobic and low-density amino acid ionic liquids

Cited by 86 publications

References 46 publications

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

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

Electronic Structure, NMR, Spin–Spin Coupling, and Noncovalent Interactions in Aromatic Amino Acid Based Ionic Liquids

Separating Rare-Earth Elements with Ionic Liquids

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