Effect of tetrabutylphosphonium cation on the physico-chemical properties of amino-acid ionic liquids

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

doi:10.1039/b600771f

Cited by 187 publications

(108 citation statements)

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“…They are complementary to ionic liquids with amino-acid-based anions. [109][110][111] The acesulfamate and saccharinate ionic liquids described in the present study are hydrophilic, but their miscibility with organic solvents depends very much on the type of cation. Pernak and co-workers found that phosphonium acesulfamate ionic liquids are hydrophobic, although they are hygroscopic.…”

Section: Discussionmentioning

confidence: 99%

Choline Saccharinate and Choline Acesulfamate: Ionic Liquids with Low Toxicities

et al. 2007

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Choline saccharinate and choline acesulfamate are two examples of hydrophilic ionic liquids, which can be prepared from easily available starting materials (choline chloride and a non-nutritive sweetener). The (eco)-toxicity of these ionic liquids in aqueous solution is very low in comparison to other types of ionic liquids. A general method for the synthesis and purification of hydrophilic ionic liquids is presented. The method consists of a silver-free metathesis reaction, followed by purification of the ionic liquid by ion-exchange chromatography. The crystal structures show a marked difference in hydrogen bonding between the two ionic liquids, although the saccharinate and the acesulfamate anions show structural similarities. The optimized structures, the energetics, and the charge distribution of cation-anion pairs in the ionic liquids were studied by density functional theory (DFT) and second-order (Møller-Plesset) perturbation theory calculations. The occupation of the non-Lewis orbitals was considered to obtain a qualitative picture of the Lewis structures. The calculated interaction energies and the dipole moments for the ion pairs in the gas phase were discussed.

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Section: Discussionmentioning

confidence: 99%

Choline Saccharinate and Choline Acesulfamate: Ionic Liquids with Low Toxicities

et al. 2007

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“…Phosphonium-based AAILs as cellulose solvents in the presence of a cosolvent (Kagimoto et al 2006). The potentially less reactive novel [TBP][DMGly] was synthesized and also tested.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the development of eco-friendly and biocompatible ILs is urgently required. Amino acid ionic liquids (AAILs) are not only halogen free but also have lower viscosity than conventional ILs at room temperature (r.t.) (Kagimoto et al 2006;Jiang et al 2008). They have the potential to be an ideal solvents for cellulose and are expected to be compatible with a subsequent enzymatic hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

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Novel cellulose pretreatment solvent: phosphonium-based amino acid ionic liquid/cosolvent for enhanced enzymatic hydrolysis

et al. 2016

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Abstract:The potential of halogen-free and imidazoliumfree phosphonium-based amino acid ionic liquids (AAILs) has been investigated as new solvents for cellulose pretreatment for the subsequent enzymatic hydrolysis of cellulose. AAILs alone did not dissolve cellulose (Avicel), even at 120°C. However, when polar solvents such as dimethylsulfoxide (DMSO) were added as cosolvents, AAILs became an acceptable solvent for cellulose at 30°C. The solubility of cellulose in tetrabutylphosphonium glycine ([TBP][Gly])/cosolvent reached 15%. The enzymatic hydrolysis of cellulose was dramatically enhanced by pretreatment with AAIL/cosolvent, and the glucose yield reached 100% when the novel AAIL tetrabutylphosphonium N,N-dimethylglycine ([TBP][DMGly]) was used in combination with DMSO as cosolvent. The enzymatic conversion of cellulose to glucose in 6% and 13% [TBP] [DMGly]/DMSO buffer solutions reached 98% and 79%, respectively. The decrease in cellulase activity owing to residual [TBP][DMGly]/DMSO was not significant. Hence, it is possible to conduct the dissolution and enzymatic hydrolysis of cellulose in a one-batch process in a phosphonium-based AAIL/cosolvent system.

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“…Recently, aspartic acid-and glutamic acid-derived ionic liquids were developed. [6][7][8] The structural features of them are functionalized dicarboxylic acid obtained from natural resources. The ionic structure is beneficial to dissolve them into ionic liquids.…”

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confidence: 99%

Aspartic Acid-derived Wear-preventing and Friction-reducing Agents for Ionic Liquids

Minami¹,

Watanabe²,

Nanao³

et al. 2008

Chemistry Letters

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The first additives that improve the tribological properties of ionic liquids were designed. They were evaluated by a ballon-flat type tribo-test under reciprocating motion. Tetraalkylammonium and tetraalkylphosphonium salts of N-protected aspartic acid was dissolved in 1-alkyl-3-methylimidzolium bis(trifluoromethylsulfonyl)imide. They prevented wear remarkably and reduced friction considerably. The salt of N-protected glutamic acid prevented wear but did not reduce friction under the conditions we have evaluated. A new model of boundary film composed of liquid clathrate structure is proposed herein.Ionic liquids are unique fluids that possess non-flammability, non-volatility, and outstanding thermo-oxidative stability. These properties are desirable for lubricating fluids, especially for lubricants used under extreme conditions. Since ionic liquids are composed of anion and cation, variation in their structure is estimated more than one million compounds.1 The tribological properties of certain ionic liquids have been reported. 2 In our previous work, 1,3-dialkylimidazolium-derived ionic liquids were found to exhibit comparable tribological properties to the conventional synthetic lubricants such as perfluoropolyethers. 3 We also pointed out the importance of additives that improve the tribological properties of ionic liquids. However, ionic liquids are strange solvents; they hardly dissolve the conventional lubricant additives. Simple carboxylic acids improved the tribological properties of dialkylimidazorium-derived ionic liquids. 4 However, these carboxylic acids are volatile and corrosive. Based on our concept of molecular design of lubricant additives, 5 chemical modification of carboxylic acid by introduction of certain functional group was examined. Here, we wish to report molecular design of the first additives that improve anti-wear properties of ionic liquids.In our preliminary work, we found that dicarboxylic acids such as succinic and glutaric acid reduced friction of 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (BIMI-TFSI), while adipic acid did not. Solubility of these simple acids in BMIM-TFSI still remains the problem. These simple compounds are volatile and corrosive in fact, however the relation between chemical structure and the tribological properties are of interest. Recently, aspartic acid-and glutamic acid-derived ionic liquids were developed.6-8 The structural features of them are functionalized dicarboxylic acid obtained from natural resources. The ionic structure is beneficial to dissolve them into ionic liquids. Thus, we synthesized trialkylammonium and trialkylphosphonium salts of these amino acids. The free amino group was protected by benzyl or acetyl group to improve the stability. Structure of the designed additives is shown in Figure 1. Samples for the tribo-test were prepared by dissolving the additive in BIMI-TFSI at the concentration of 10 mmol kg À1 .The tribological properties were obtained using a ball-onflat type tribo-tester under reciprocating motion a...

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Effect of tetrabutylphosphonium cation on the physico-chemical properties of amino-acid ionic liquids

Abstract: Tetraalkylphosphonium-based amino-acid ionic liquids show lower viscosities and higher decomposition temperatures (>300 degrees C) than previously reported ammonium-based amino-acid ionic liquids.

Cited by 187 publications

References 24 publications

Choline Saccharinate and Choline Acesulfamate: Ionic Liquids with Low Toxicities

Choline Saccharinate and Choline Acesulfamate: Ionic Liquids with Low Toxicities

Novel cellulose pretreatment solvent: phosphonium-based amino acid ionic liquid/cosolvent for enhanced enzymatic hydrolysis

Aspartic Acid-derived Wear-preventing and Friction-reducing Agents for Ionic Liquids

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