- Micelle formation as a factor influencing the mode(s) of metal ion partitioning into: N -alkylpyridinium-based ionic liquids (ILs): Implications for the design of IL-based extraction systems
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Prior studies of metal ion partitioning between an acidic aqueous phase and an ionic liquid in the presence of a macrocyclic polyether have demonstrated that the overall partitioning is a composite of three distinct pathways: neutral complex/ion-pair extraction, exchange of a cationic metal-crown ether (CE) complex for the cationic constituent of the IL, and exchange of the metal ion for a hydronium ion in a CE-H3O+ complex formed during acid preconditioning of the IL. The obvious undesirability of the ion-exchange pathways, which can lead to substantial loss of the IL cation to the aqueous phase, has led to efforts to identify means by which these processes can be suppressed or eliminated. Prior work with N,N′-dialkylimidazolium and quaternary ammonium bis [(trifluoromethyl)sulfonyl]imides has shown that increasing the hydrophobicity of the IL cation can be an effective means of diminishing the contribution of ion-exchange. Work with the corresponding N-alkylpyridinium ILs, however, indicates that in certain instances, an increase in the hydrophobicity of the IL cation is accompanied by a marked increase in its propensity to self-associate, leading to the formation of micelles in the aqueous phase. The net effect is to diminish or even negate the expected beneficial effect of IL cation hydrophobicity in reducing the contribution of ion exchange to the overall metal ion partitioning process, adversely impacting the "greenness" of extraction processes employing these ILs.
- Wankowski, James L.,Kaul, Michael J.,Dietz, Mark L.
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supporting information
p. 5674 - 5682
(2017/12/06)
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- Ultrafast dynamics in aromatic cation based ionic liquids: A femtosecond raman-induced kerr effect spectroscopic study
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We studied the ultrafast dynamics of 40 aromatic cation based ionic liquids (ILs) by means of femtosecond Ramaninduced Kerr effect spectroscopy. The low-frequency Kerr spectra (ca. 0.3700 cm1) of the ILs were obtained from the Kerr transients by Fourier-Transform deconvolution analysis. The low-frequency Kerr spectra in the frequency range less than 200 cm-1 coming mainly from the intermolecular vibrations for the ILs were discussed in terms of (i) anion dependence, (ii) imidazolium cations vs. pyridinium cations, (iii) alkyl group dependence, and (iv) effect of methylation in aromatic cations. Several liquid properties, such as density, viscosity, electrical conductivity, and surface tension, of the present sample ILs at 293K were also estimated in this study. We clarified that the aromatic cation based ILs show a different relation of the first moment of the low-frequency spectral band to the bulk liquid parameter, which is the square root of surface tension divided by liquid density, from aprotic molecular liquids. The slope of the first moment to the bulk parameter for the aromatic cation based ILs is gentler than that for aprotic molecular liquids.
- Shirota, Hideaki,Kakinuma, Shohei,Takahashi, Kotaro,Tago, Akito,Jeong, Hocheon,Fujisawa, Tomotsumi
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supporting information
p. 1106 - 1128
(2016/10/11)
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- PYRIDINIUM=BIS(FLUOROSULFONYL)IMIDE AND MANUFACTURING METHOD THEREOF
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PROBLEM TO BE SOLVED: To provide novel pyridinium=bis(fluorosulfonyl)imide having an alkyl group having 9 to 12 carbon atoms or an aralkyl group having 7 to 13 carbon atoms at 1-position of pyridinium and a hydrogen atom or an alkyl group having 1 to 6 carbon atoms on a pyridine ring, capable of being used for an electrolyte, an antistatic agent and the like for electrical chemical devices such as cell, capacitor, condenser and solar cell. SOLUTION: There is provided pyridinium=bis(fluorosulfonyl)imide represented by the formula (1), where R1 represents an alkyl group having 9 to 12 carbon atoms or an aralkyl group having 7 to 13 carbon atoms, R2 represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, excluding 1-nonyl pyridinium=bis(fluorosulfonyl)imide and 1-dodecyl-4-methyl pyridinium=bis(fluorosulfonyl)imide. COPYRIGHT: (C)2015,JPOandINPIT
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Paragraph 0033
(2018/10/31)
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- Synthesis, characterization and conductivity of quaternary nitrogen surfactants modified by the addition of a hydroxymethyl substructure on the head group
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Two novel series of hydroxymethyl group-appended quaternary nitrogen surfactants (QNSs) based on the aliphatic N-alkyl-trimethylammonium and aromatic N-alkylpyridinium head groups were synthesized from the appropriate nitrogen head group precursor and 1-bromoalkane. The QNSs were characterized using 1H and 13C nuclear magnetic resonance and infrared spectroscopy, and their purity confirmed using elemental analysis. The solution behavior of the QNSs was investigated by conductivity, assessing both the aggregation concentration as well as the amount of counter-ion dissociation. The results showed a general decrease in the aggregation concentration for the compounds with the hydroxymethyl addition, where the pyridinium compounds were more affected than the ammonium QNSs. In contrast, the extent of counter-ion dissociation (α) from the aggregate was slightly increased for the ammonium compounds but that of the pyridinium compounds was not generally affected by the structural modification.
- Jordan, Deborah,Tan, Eng,Hegh, Dylan
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p. 587 - 592
(2012/10/29)
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- Preparation of the pyridinium salts differing in the length of the N-alkyl substituent
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Quaternary pyridinium salts with chains ranging from C8 to C20 belong in the large group of cationic surfactants. In this paper, the preparation of such cationic surface active agents based on the pyridinium moiety and differing in the length of the N-alkyl chain is described. Additionally, HPLC technique was established to distinguish each prepared pyridinium analogue. This study represents universal method for preparation and identification of quaternary pyridinium detergents.
- Marek, Jan,Stodulka, Petr,Cabal, Jiri,Soukup, Ondrej,Pohanka, Miroslav,Korabecny, Jan,Musilek, Kamil,Kuca, Kamil
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experimental part
p. 1967 - 1972
(2010/09/08)
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- Synthesis of imidazolium and pyridinium-based ionic liquids and application of 1-alkyl-3-methylimidazolium salts as pre-catalysts for the benzoin condensation using solvent-free and microwave activation
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An efficient one-pot procedure for the synthesis of ionic liquids based on nitrogen-containing heterocycles, imidazolium or pyridinium under 'green chemistry' conditions has been described. Imidazolium salts and DBU have been found to catalyze efficiently the benzoin condensation giving good yields within very short reaction time using solvent-free microwave activation conditions.
- Aupoix, Audrey,Pégot, Bruce,Vo-Thanh, Giang
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experimental part
p. 1352 - 1356
(2010/04/02)
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- Biodegradable pyridinium ionic liquids: Design, synthesis and evaluation
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A range of ionic liquids (ILs) with a pyridinium cation were synthesised and their biodegradability was evaluated using the CO2 Headspace test (ISO 14593). ILs bearing an ester side chain moiety were prepared from either pyridine or nicotinic acid and showed high levels of biodegradation under aerobic conditions and can be classified as 'readily biodegradable'. In contrast, pyridinium ILs with alkyl side chains showed significantly lower levels of biodegradability in the same test. The utility of the biodegradable IL 6c as a reaction solvent for the Diels-Alder reaction was also investigated.
- Harjani, Jitendra R.,Singer, Robert D.,Garcia, M. Teresa,Scammells, Peter J.
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experimental part
p. 83 - 90
(2010/04/22)
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- Binding of N-Alkylpyridinium Chlorides to Nonionic Micelles
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Binding of N-alkylpyridinium chlorides (C10, C12, and C14) to dodecyl oxyethylene ether (C12E6 and C12E8) micelles is determined in the presence of 5 mol m-3 NaCl at various temperatures by potentiometry which employs an electrode responsive to the surfactants.Binding affinity is expressed in terms of a distribution coefficient, Kx, of a cationic surfactant between the aqueous bulk phase and the nonionic micellar phase, and is larger for an alkylpyridinium cation with a longer hydrocarbon chain.The values of Kx are divided into three regions depending on the mole fraction of bound cationic surfactant in a micelle, X.At X x remains constant, while for 0.02 0.2.The constant Kx values reflect an intrinsic binding affinity (K0).With increase in X, electrostatic repulsion among bound cationic surfactants causes decreased Kx values, which may be analyzed by a simple electrostatic theory to estimate the position of bound cationic head groups.From the temperature dependence of K0, it is found that the binding process is nearly athermal for C12E8 micelles but exothermic for C12E6 micelles, the latter associated with the growth of micellar size with temperature.
- Shirahama, Keishiro,Nishiyama, Yoshinori,Takisawa, Noboru
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p. 5928 - 5930
(2007/10/02)
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- Fluorescence Study of Pyrene and Naphthalene in Cyclodextrin-Amphiphile Complex Systems
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Amphiphilic molecules are shown to interact with pyrene-β-cyclodextrin (Py-β-CD) complexes leading to an extremely hydrophobic environment for pyrene (Py) in aqueous solution.The three-component systems give rise to a 1:1:1 complex of Py, β-CD, and the surfactant.The binding constant of Py and β-CD increases significantly in the presence of the surfactants, which suggests an improvement in the solubility of Py in aqueous β-CD systems.Larger binding constants of Py and β-CD were obtained in the presence of shorter chain amphiphiles between C4 and C16 surfactants.Fluorescence quenching of Py in Py-β-CD-pyridinium surfactants (CnPd(1+)x(1-)) systems obeyed first-order kinetics, which were independent of the concentration of CnPd(1+)X(1-) above a certain concentration, while the quenching rate constant was markedly affected by the chain length of the pyridinium surfactants.Smaller rate constants are obtained for longer chain surfactants.The observed kinetics are explained in terms of a 1:1:1 complex formation of Py, β-CD, and CnPd(1+)X(1-), and the chain-length-dependent rate constants are interpreted by assuming a "diffusion-controlled reaction within limited space".On the other hand, Stern-Volmer kinetics were observed for Py fluorescence quenching in the Py-β-CD-C16C2V(2+) (1-ethyl-1'-hexadecyl-4,4'-bipyridinium ion) system.This is ascribed to the long-range nature of the reaction in Py(S*1)-viologen group systems compared with that in Py(S*1)-pyridinium group systems.In the naphthalene-β-CD (N-β-CD) system, reduced association constants were observed in the presence of surfactants, which is markedly different from that observed in the Py-βCD system.A determination of the dynamic parameters of the equilibrium showed that the entry rate constant of naphthalene into β-CD was reduced in the presence of surfactants, while the exit rate constant was unchanged.The exit rate was appreciably reduced in the Py-β-CD system on addition of surfactants.Quenchers such as oxygen, nitromethane, copper(II) ion, thallium(I) ion, etc., which reside in the aqueous phase also quench excited Py in β-CD.The influence of CD with and without surfactant on the rate depends on the nature of the quenching reaction, and on the degree of screening by the host system on the guest molecule.It is demonstrated in the present study that the introduction of amphiphilic molecules into the Py-β-CD complex system improves the organization of the system and simplifies the reaction mechanism.The unique types of reaction kinetics observed are due to the selective organization of reactants in the CD system.
- Hashimoto, S.,Thomas, J. K.
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p. 4655 - 4662
(2007/10/02)
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