- Study on absorption and spectral properties of H2S in carboxylate protic ionic liquids with low viscosity
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The exorbitant price and high viscosity are two major disadvantages for ionic liquids (ILs), which influence their practical applications in gas separation. Here we synthesized ten carboxylate protic ionic liquids (PILs), containing N-ethylmorpholine acetate, N-ethylmorpholine propionate, N-ethylmorpholine butyrate, N-ethylmorpholine methoxylacetate, 4-(2-hydroxyethyl) morpholine acetate, and 4-(2-hydroxyethyl) morpholine methoxyacetate, triethylamine acetate, triethylamine propionate, triethylamine propionate, and triethylamine methoxylacetate, with low cost and viscosity for absorption of H2S. The densities and viscosities of these carboxylate PILs were measured in the temperature range of (298.2 to 333.2) K at atmospheric pressure. The solubility of H2S in these PILs was determined using an isochoric saturation technique at 298.2–318.2 K and 0–1.096 bar. It was found that the solubility of H2S in these PILs increased with the increasing pressure and length of the alkyl chains on the carboxylic acid. The absorption processes obeyed Henry's law within the given experimental conditions and Henry's constants were calculated from solubility data. In addition, the FTIR and NMR spectral properties in the absorption process of H2S in N-ethylmorpholine butyrate [NEMH][Bu] also were investigated to present important information on absorption mechanism. The results indicated that [NEMH][Bu] demonstrated a highest absorption capacity among these PILs and absorption of H2S is a physical behavior. Comparisons of PILs with the common ILs and organic solvents were also done to demonstrate the advantages of PILs.
- Zhao, Tianxiang,Li, Ping,Feng, Xi,Hu, Xingbang,Wu, Youting
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- Synthesis of micro/mesoporous silica material by duallate method as a heterogeneous catalyst support for alkylation
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A series of micro/mesoporous composites were synthesized using non-ionic block copolymer Pluronic P123 and protic ionic liquid (triethylamine acetate) as the colates. The structures of all the composites were characterized by using small angle X-ray scattering, N2 gas sorption, dynamic laser light scattering (DLS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results reflected that the structure of the final silica materials changes along with the content of protic ionic liquid (PIL) and hydrothermal temperature. It was found that the sample whose mass ratio of PIL to (P123 + PIL) was 40% had a t-plot micropore area of 404 m2 g-1 at the hydrothermal temperature of 373 K, without destroying the ordered mesoporous structure. The formation mechanism of the micro/mesoporous silica which is based on the interaction between PIL and P123 is tentatively elucidated. 12-Tungstophosphoric acid (HPW) catalysts supported on these micro/mesoporous materials were prepared by impregnation, and their catalytic performances were investigated in the alkylation of o-xylene with styrene. Alkylation results showed that all the catalysts showed high catalytic performance in terms of propane conversion and selectivity to propene.
- Zhao, Shuo,He, Man,Zhou, Yuming,Sheng, Xiaoli,Fu, Xiaoqin,Zhang, Yiwei
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- Peptides in aqueous protic ionic liquid solutions: Apparent and transfer volumes at 298.15 K and at 0.1 MPa
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The densities of glycine based peptides namely glycyl-glycine (digly), glycine-?-valine (gly-val), glycyl-?-leucine (gly-leu) and glycyl-glycyl-glycine (triglycine/trigly) in aqueous solutions containing ~0.20 mol·kg?1 of triethylammonium acetate [TEAA], triethylammonium glycolate [TEAG], triethylammonium pyruvate [TEAPy] and triethylammonium propionate [TEAP] protic ionic liquids (PILs) are reported at 298.15 K and at atmospheric pressure. Experimental density data obtained for these systems were used to estimate apparent molar volume (?V), the limiting apparent molar volume (?V0), partial molar volume of solute (Vˉ2) and partial molar volume of mixed solvent (PILs + water) (Vˉ1). The change in limiting apparent molar volume due to transfer (Δtr?V0) of peptides from water to aqueous ionic liquid solutions were also estimated. The outcomes obtained from all these thermodynamic parameters were discussed in terms of ion–peptide interactions, ion–ion interactions, hydrophobic solvation, peptide group contributions to limiting volumes, etc.
- Dagade, Dilip H.,Musale, Shrikant P.,Patil, Kunal R.
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- Infrared spectroscopic study on chemical and phase equilibrium in triethylammonium acetate
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Protic ionic liquid (PIL) triethylammonium acetate was prepared by mixing equimolar amounts of acetic acid and triethylamine, and then studied using the combination of the Attenuated Total Reflection Fourier Transform Infrared spectroscopy, in-situ infrared spectroscopy, pH, and conductivity titration measurements. It was found that the equimolar synthesized triethylammonium acetate was separated into two layers, which suggesting that there were both chemical and phase equilibrium in this solution. Molecular species could be directly observed in the IR spectra over the range of 1200-1800 cm?1 and also checked by 1H NMR. Based on analysis, the upper layer was rich in amine with little acid and PIL, and the down layer was rich in PIL with residual acetic acid and amine. And single PIL-rich layer could be separated into two layers again when the mole ratio of newly added triethyamine to the theoretical produced triethylammonium acetate reached 0.12.
- Lv, Yi Qi,Guo, Yan,Luo, Xiao Yan,Li, Hao Ran
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- Synthesis and potent antimicrobial activity of novel coumarylthiazole α-aminophosphonates derivatives
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Abstract: Herein, we reported a novel series of?α-aminophosphonates derivatives (IV)a–m bearing an important pharmacophore coumarylthiazole moiety. All the new compounds have been synthesized?via?Kabachnik–Fields reaction under ultrasonic irradiation. The products were obtained in good yield with a simple workup and were confirmed using various spectroscopic methods. All these compounds (IV)a–m were screened for their in vitro for antimicrobial activity against thirteen Gram-negative bacteria and five Gram-positive bacteria and Candida albicans strains. The results showed that all the synthesized compounds exhibited moderate antibacterial activities against both references and multidrug-resistant and antifungal strains. The compound?(IV)e?showed the highest activities against all pathogens of the tested microbial strains with?MIC of 0.125?μg/mL.?The compounds (IV)h, (IV)f, (IV)b, and (IV)d exhibited moderate and promising activities with MIC of 0.125?μg/mL. Structure–activity relationship revealed that inhibitory activity of the synthesized compounds is related to the type of the substituted group on phenyl rings, and these results showed that the electron-donating groups at?ortho?and?para?positions have a high relationship increasing antimicrobial activities than the electron‐withdrawing groups. These results confirm that coumarylthiazole α-aminophosphonates compounds can be potential antimicrobial drugs candidate. Graphic abstract: [Figure not available: see fulltext.].
- Boukhari, Abbes,Cheraiet, Zinelaabidine,Djahoudi, Abdelghani,Litim, Bilal,Meliani, Saida
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- Biocompatible Ionic Liquid Promote One-Pot Synthesis of 2-Amino-4H-Chromenes Under Ambient Conditions
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Abstract: The synthesis of 2-amino-4H-chromenes through one-pot multicomponent reactions has received great attention due to the high atom efficiency and the broad bioactivities of the products. Here, the catalytic performances of a series of functional ionic liquids towards this type of reaction were investigated and the results showed that the ionic liquid, choline acetate ([Choline][Ac]), could efficiently promote this reactions under room temperature without the necessary of organic solvents. The reaction is easy to be conducted and the following work-up procedures are very simple. The pure products can be obtained through extraction and washing procedures, no column separation procedures are needed. Intriguingly, this reaction system can be easily scaled up to multi-gram, suggesting its perspective in industrial applications. In addition, the ionic liquid [Choline][Ac] can be easily prepared from cheap and biocompatible materials, and it can be feasibly recycled and reutilized for at least five cycles. Graphic Abstract: Various aldehydes, malononitrile and activated phenols could be converted to thecorresponding 2-amino-4H-chromenes with good to excellent isolated yields underthe catalysis of choline acetate at room temperature. [Figure not available: see fulltext.]
- Zhu, Anlian,Li, Qixing,Feng, Wanlu,Fan, Dongshuang,Li, Lingjun
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p. 720 - 733
(2020/08/07)
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- QUINONE METHIDE AND AMMONIUM SALT ANTIPOLYMERANT COMPOSITION AND METHOD
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Described are compositions and methods for inhibiting polymerization of a monomer (e.g., styrene) composition a quinone methide polymerization retarder and an ammonium salt. In a mixture, the ammonium salt improves the efficacy of the quinone methide polymerization retarder and provides greater antipolymerant activity. In turn, the mixture reduces or prevents apparatus fouling and improves the purity of monomer streams.
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Paragraph 164-165
(2021/04/17)
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- Simple protic ionic liquid [Et3NH][HSO4] as a proficient catalyst for facile synthesis of biscoumarins
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Abstract: We have explored a number of protic ionic liquids (PILs) as a catalyst for the synthesis of biscoumarins by condensation of 4-hydroxycoumarin with an aromatic aldehyde. Methylimidazolium- and triethylammonium-based PILs were synthesized by simple neutralization reaction with protic acids. Triethylammonium hydrogen sulfate [Et3NH][HSO4] was found to be the best among the studied PILs concerning the yield of products and reaction time period. Different biscoumarin derivatives were synthesized based on 4-hydroxycoumarin and various substituted aromatic aldehydes at optimum reaction conditions. Obtained products were separated just by simple filtration. The facile method does not require additional purification for formed products. The catalyst has shown better yields along with outstanding recyclability, providing an environmental benign protocol for the synthesis of biscoumarin derivatives. Graphical Abstract: Screening of simple protic ionic liquids as a catalyst in the synthesis of biscoumarins, out of which [Et3NH][HSO4] was found to be best among the studied PILs.
- Patil, Sandip K.,Awale, Deepak V.,Vadiyar, Madagonda M.,Patil, Suryakant A.,Bhise, Sagar C.,Kolekar, Sanjay S.
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p. 5365 - 5376
(2017/09/23)
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- Preparation method of key midbody allene sulfoxide matter of dexamethasone
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The invention discloses a preparation method of key midbody allene sulfoxide matter of dexamethasone. The preparation method includes steps of adding an organic solvent (I) containing weak acid and weak base salt to a compound shown in Formula A; then adding to an organic solvent (II) containing chorine fenbendazole and reacting; after reaction, collecting a compound shown in Formula B from a reaction product. The method has the beneficial effects that the product does not use cyanide and heavy metals, and is good for large-scale industrial production; the yield is over 124%, which is greatly higher than that of the prior art; the production cost is reduced, and the technical innovation of the preparation technique of dexamethasone and other steroids containing C17 side chain is promoted; meanwhile, the method also provides a thinking for the preparation of the steroids with the side chain. The reaction general formula is shown as below: FORMULA.
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Paragraph 0060; 0062; 0063
(2017/08/31)
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- Efficient and selective N-, S- and O-acetylation in TEAA ionic liquid as green solvent. Applications in synthetic carbohydrate chemistry
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Background: The ionic liquid triethylammonium acetate (TEAA) was found to be an efficient solvent in the acetylation of alcohols, amines, oximes and thiols to their corresponding acetyl compounds using only a 10% excess of acetic anhydride under mild conditions. Moreover TEAA is not only an inexpensive and recyclable solvent but also an anomeric selective catalyst in the per-O-acetylation of sugar moieties. Methods: Simple and effective organic synthesis protocols were provided for the selective acetylation of several substrates. The products were fully characterized by 1H and 13C NMR spectroscopy and the anomeric ratios were obtained from the 1H spectra. Results: Structurally diverse alcohols, phenols, thiols, amines, carbohydrates and oximes underwent acylation under mild conditions by this procedure to provide the corresponding acetates in excellent yields. TEAA ionic liquid is unique in its capability to act as both, solvent and high selective catalyst. As expected, the reaction proceeds with high b anomeric selectivity for sugars derivatives. Moreover, the ionic liquid was regenerated, recycled and reused for three times without apparent loss of reactivity and selectivity in all cases. Conclusions: The present procedure provides a powerful and versatile acylation method for alcohols, phenols, thiols, amines, oximes and carbohydrates. This protocol is endowed with several unique merits: selectivity, cost-efficiency, atom-economy and mild reaction conditions tolerable to acid sensitive functionalities. With these features, this method may be considered as a better alternative for the acetylation of a wide range of substrates.
- Lafuente, Leticia,Díaz, Gisela,Bravo, Rodolfo,Ponzinibbio, Agustín
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p. 195 - 200
(2016/02/26)
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- [HSO4]-catalyzed eco-friendly and expeditious synthesis of thiazolidine and oxazolidine derivatives
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The present study reports a facile and green approach for the synthesis of thiazolidine/oxazolidine derivatives 4(a-u) in excellent yields (92-98%) with high purity. The protocol involves a one-pot three-component reaction of substituted 1,3-diketones 1(a-g), cyanates 2(a-c) and ethylchloroacetate (3) in ionic liquid [Et3NH][HSO4] under solvent-free conditions. The notable feature of this pathway is that the ionic liquid possesses both catalytic as well as medium engineering capability in this protocol. Use of [Et3NH][HSO4] as a catalyst and an environmentally benign solvent eliminates the need for a volatile organic solvent and additional catalyst. This ionic liquid is air and water stable and easy to prepare from cheap amine and acid. The present synthetic route is a green protocol offering several advantages, such as excellent yield of products, mild reaction conditions, minimizing chemical waste, shorter reaction time, simple operational procedure, easy preparation of the catalyst and its recyclability up to five cycles without any noticeable loss in catalytic activity. The protocol is applicable to a broad substrate scope. The optimization of conditions carried out in the present study revealed that 20 mol% of ionic liquid catalyst under solvent-free conditions at 120 °C are the best reaction parameters for the synthesis of thiazolidine/oxazolidine derivatives in excellent yields. This journal is
- Malla, Ali Mohammed,Parveen, Mehtab,Ahmad, Faheem,Azaz, Shaista,Alam, Mahboob
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p. 19552 - 19569
(2015/06/01)
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- Vaporization of protic ionic liquids studied by matrix-isolation fourier transform infrared spectroscopy
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Several protic ionic liquids (PILs) with a wide range of pKa differences (ΔpKa) between the parent acid and base molecules were thermally evaporated in vacuum, trapped on a CsI plate by a cryogenic neon matrix-isolation method, and studied by Fourier transform infrared spectroscopy and density functional theory calculations. The parent neutral molecules and proton-transferred cation-anion pair species were identified as chemical components evaporated from the PILs with lower and higher ΔpKa values, respectively. The ΔpKa-dependent vaporization mechanism is discussed in terms of thermodynamic equilibrium between acid-base and anion-cation systems in the liquid phase.
- Horikawa, Mami,Akai, Nobuyuki,Kawai, Akio,Shibuya, Kazuhiko
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p. 3280 - 3287
(2014/06/09)
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- Green approach towards the facile synthesis of dihydropyrano(c)chromene and pyrano[2,3-d]pyrimidine derivatives and their biological evaluation
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A simple and efficient one-pot synthesis of heteroaryl-substituted dihydropyrano(c)chromenes and pyrano[2,3-d]pyrimidines has been developed. Reaction proceeds via initial Knoevenagel, subsequent Michael and final heterocyclization reactions of heteroaryl aldehyde, malononitrile, and barbituric acid/dimedone. Triethylammonium acetate acts as a green catalyst as well as reusable solvents for this reaction. Short reaction time, environment friendly procedure, reusability, and excellent yields are the main advantages of this procedure. All synthesized compounds have shown good antibacterial activity against different microbial stains but not active against cancer cell lines.
- Paliwal, Pradeep K.,Jetti, Srinivasa Rao,Jain, Shubha
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p. 2984 - 2990
(2013/07/26)
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- Temperature effect on the molecular interactions between two ammonium ionic liquids and dimethylsulfoxide
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To understand the molecular interactions between newly synthesized ammonium ionic liquids (ILs) and highly polar solvent dimethylsulfoxide (DMSO), precise measurements such as densities (ρ), ultrasonic sound velocities (u) and viscosities (η) have been performed over the whole composition range at temperature ranging from 298.15 to 308.15 K and at atmospheric pressure. The ILs investigated in the present study included diethyl ammonium acetate ([Et 2NH][CH3COO], DEAA) and triethyl ammonium acetate ([Et3NH][CH3COO], TEAA). Further, to gain some insight into the nature of molecular interactions in these mixed solvents, we predicted the excess molar volume (VE), the deviation in isentropic compressibilities (ΔKs) and deviation in viscosity (Δη) as a function of the concentration of IL using the measured properties of ρ, u and η, respectively. Redlich-Kister polynomial was used to correlate the results. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMSO molecules and their structural factors.
- Govinda, Varadhi,Attri, Pankaj,Venkatesu,Venkateswarlu
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experimental part
p. 218 - 225
(2012/05/31)
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- Active species formed in a Fenton-like system in the medium of triethylammonium acetate ionic liquid for hydroxylation of benzene to phenol
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High-valent iron(IV)-oxo species was proved to be the main oxidizing species for hydroxylation of benzene to phenol by a Fenton-like reagent in triethylammonium acetate ionic liquid via UV-vis and ESI-MS characterization, while hydroxyl radical was excluded by detailed investigations. It was found that the formation of hydroxyl radical was prohibited by the reduction of redox potential of Fe(III)/Fe(II) couple in triethylammonium acetate medium, leading to a decreased over-oxidation of benzene than that in aqueous solution. The reaction mechanisms for hydroxylation of benzene, as well as for over-oxidation of phenol by iron(IV)-oxo species were proposed. The latter is partly prohibited by the hydrogen-bond interaction between as-produced phenol and acetate anion of the ionic liquid.
- Hu, Xiaoke,Zhu, Liangfang,Wang, Xueqin,Guo, Bin,Xu, Jiaquan,Li, Guiying,Hu, Changwei
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experimental part
p. 41 - 49
(2011/07/09)
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- Measurements and molecular interactions for N, N-dimethylformamide with ionic liquid mixed solvents
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To understand the molecular interactions between N,N-dimethylformamide (DMF) with two families of ionic liquids (ILs), we have measured thermophysical properties such as densities and ultrasonic sound velocities (u) over the whole composition range at 25 ?°C under atmospheric pressure. The excess molar volume (VE) and the deviation in isentropic compressibilities (??Ks) were predicted using these properties as a function of the concentration of IL. These results are fitted to the Redlich-Kister polynomials. The materials investigated in the present study included two families of ILs such as ammonium salts and imidazolium salts. Diethylammonium acetate ([Et2NH][CH3COO], DEAA), triethylammonium actetate ([Et3NH][CH3COO], TEAA), triethylammonium dihydogen phosphate ([Et3NH][H2PO4], TEAP), and triethylammonium sulfate ([Et3NH][HSO4], TEAS) are ammonium salts and 1-benzyl-3-methylimidazolium chloride ([Bmim][Cl]) belongs to the imidazolium family. The intermolecular interactions and structural effects were analyzed on the basis of the measured and the derived properties. A qualitative analysis of the results is discussed in terms of the ion-dipole, ion-pair interactions, and hydrogen bonding between ILs and DMF molecules and their structural factors. ? 2010 American Chemical Society.
- Attri, Pankaj,Reddy, P. Madhusudan,Venkatesu,Kumar, Anil,Hofman
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experimental part
p. 6126 - 6133
(2010/10/01)
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- Density and ultrasonic sound speed measurements for N,N-dimethylformamide with ionic liquids
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To understand the molecular interactions between N,N-dimefhylformamide with two families of ionic liquids, the thermophysical properties such as densities and ultrasonic sound speeds have been measured over the entire composition range at 25 °C under atmospheric pressure. The materials investigated in the present study include two families of ionic liquids, viz., ammonium salts and imidazolium salts. Diethyl ammonium acetate, triethyl ammonium acetate, triethyl ammonium dihydrogen phosphate and triethyl ammonium sulphate are the ammonium salts while 1-benzyl-3-methylimidazolium chloride belongs to the imidazolium family. The intermolecular interactions and structural effects are analyzed on the basis of the measured and derived properties. A qualitative analysis of the results are discussed in terms of the ion-dipole interactions, ion-pair interactions and hydrogen bonding between the ionic liquids and N,N-dimethylformamide molecules.
- Attri, Pankaj,Reddy, P. Madhusudhan,Venkatesu
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experimental part
p. 736 - 742
(2011/01/05)
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- Ionicity and proton transfer in protic ionic liquids
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Proton transfer in protic ionic liquids is poorly understood. Some acid/base proton transfer reactions do not proceed to the extent that is expected from ΔpKaaq data from aqueous solutions, yet some do. In this work we have investigated protic ionic liquids obtained by proton transfer from a common acid, acetic acid, to a range of amine bases of similar pKaaq values. Probe indicator observations, transport property data allowing the construction of Walden plots and computational studies all suggest that there is a clear distinction between the behaviour of simple primary vs. tertiary amines, the proton transfer being more complete in the former case than the latter. The origins of this seem to be related to the hydrogen bonding ability of the ammonium ions in providing a good solvating environment for the ions produced by the proton transfer.
- Stoimenovski, Jelena,Izgorodina, Ekaterina I.,MacFarlane, Douglas R.
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experimental part
p. 10341 - 10347
(2011/04/27)
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- Nonadditivity of Faradaic currents and modification of capacitance currents in the voltammetry of mixtures of ferrocene and the cobaltocenium cation in protic and aprotic ionic liquids
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Unexpected nonadditivity of currents encountered in the electrochemistryof mixtures of ferrocene (Fc) and cobaltocenium cation (Cc+) as the PF6- salt has been investigated by direct current (dc) and Fourier-transformed alternating current (ac) cyclic vol tammetry in two aprotic (1-butyl-3-methylimidazolium tetrafluoroborate and 1-butyl-3-methylimidazolium hexafluorophosphate) and three protic (triethylammonium formate, bis(2-hydroxyethyl)ammonium acetate, and triethylammonium acetate) ionic liquids (ILs). The voltammetry of the individual Fc0/+ and Cc+/0 couples always exhibits near-Nernstian behavior at glassy carbon and gold electrodes. As expected for anideal process, the reversible formal potentials and diffusion coefficie nts at 23 ± 1°C in each IL determined from measurement on individual Fc and Cc+ solutions were found to be independent of electrode material, concentration, and technique used for the measurement. However, when Fc and Cc+ were simultaneously present, the dc and ac peak currents per unit concentration for the Fc0/+ and Cc+/0 processes were found to be significantly enhanced in both aprotic and protic ILs. Thus, the apparent diffusion coefficient values calculated for Fc and Cc+ were respectively found to be about 25 and 35percent larger than those determined individually in the aprotic ILs. A similar change in the Fc0/+ mass transport characteristics was observed upon addition of tetrabutylammonium hexafluorophosphate (Bu4NPF 6), and the double layer capacitance also varied in distinctly different ways when Fc and Cc+ were present individually or in mixtures. Importantly, the nonadditivity of Faradaic current is not associated with a change in viscosity or from electron exchange as found when some solutes are added to ILs. The observation that the 1H NMR T1 relaxation times for the proton resonance in Cc+ also are modified in mixed systems implies that specific interaction with aggregates of the constituentIL ionic species giving rise to subtle structural changes plays an impo rtant role in modifying the mass transport, double layer characteristics, and dynamics when solutes of interest in this study are added to ILs. Analogous voltammetric changes were not observed in studies in organic solvent media containing 0.1 M added supporting electrolyte. Implicationsof the nonadditivity of Faradaic and capacitance terms in ILs are consi dered.
- Shiddiky, Muhammad J. A.,Torriero, Angel A. J.,Zhao, Chuan,Burgar, Iko,Kennedy, Gareth,Bond, Alan M.
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supporting information; experimental part
p. 7976 - 7989
(2009/12/03)
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- Triethylammonium acetate (TEAA): A recyclable inexpensive ionic liquid promotes the chemoselective aza- and thia-Michael reactions
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A new, highly efficient, inexpensive, recyclable, mild, convenient, and green protocol for chemoselective aza/thia-Michael addition reactions of amines/thiols to α,β-unsaturated compounds using triethylammonium acetate (TEAA) ionic liquid was developed. The catalyst can be recycled ten times and obviate the need for toxic and expensive catalysts.
- Verma, Akhilesh K.,Attri, Pankaj,Chopra, Varun,Tiwari, Rakesh K.,Chandra, Ramesh
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experimental part
p. 1041 - 1047
(2009/11/30)
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- Method of hybridizing genes
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Provided are a method of hybridizing genes, including applying to a gene microarray a hybridization solution in which a compound represented by formula (1) is added: where each of R1, R2, and R3 is independently a straight or branched C1-C5 alkyl; and X?is an anion of an organic acid; and a method of using a compound represented by formula (1) as an additive to a hybridization solution.
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- La modelisation dynamique et l'analyse thermique appliquees a un systeme chimique: determination d'une enthalpie reactionelle
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Thermal regulation and energy storage in the solar system can be studied with a chemical procedure.A method of dynamical modelisation used in the case of thermal systems is builded for the reaction of acetic acid with triethylamine.Identical results to those of classical calorimetry are obtained which proves the validity of the model.
- Balbi, Nicole
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p. 753 - 755
(2007/10/02)
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- Structural studies of diorganotin(IV) carboxylates. X-ray and NMR structures of Me2Sn(OAc)2 and a 7-coordinate tin anion, Me2Sn(OAc)3-NMe4 +·2CHCl3
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The X-ray crystal and molecular structure of Me2Sn(OAc)2 is reported and compared with previous predictions based on other structural methods. The molecule is found to be monomeric and 6-coordinate at tin in the solid state. The Me-Sn-Me angle of 135.9 (2)° is in close agreement with the value predicted from solid-state and solution NMR studies. 119Sn NMR data are also reported for this compound. Me2Sn(OAc)2 crystallizes in the monoclinic space group C2/c (No. 15) with a = 12.712 (2) A?, b = 5.220 (1) A?, c = 14.365 (3) A?, β = 92.80 (1)°, and Z and 4; R refined to 0.022 and Rw to 0.029 for 1041 reflections. Me2Sn(OAc)2 reacts with Me4N+OAc- in CHCl3 solution to give a quantitative yield of Me2Sn(OAc)3-NMe4+. Me2Sn(OAc)3-NMe4+ crystallizes with two molecules of CHCl3 in orthorhombic space group Pbca (No. 61) with a = 16.717 (2) A?, b = 17.475 (2) A?, c = 18.242 (3) A?, and Z = 8; R refined to 0.059 and Rw to 0.047 for 1723 reflections. Me2Sn(OAc)3-NMe4+ is 7-coordinate at tin and has a Me-Sn-Me angle of 165.8°. CHCl3 in the crystal lattice is weakly hydrogen bonded to several oxygens of the tin complex. Solution 1H, 13C, and 119Sn and solid-state 13C NMR studies provide evidence for retention of the high coordination number in solution and for rapid, reversible acetate exchange in solution.
- Lockhart, Thomas P.,Calabrese, Joseph C.,Davidson, Fredric
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p. 2479 - 2483
(2008/10/08)
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