- Imidazolium salt-modified porous hypercrosslinked polymers for synergistic CO2 capture and conversion
-
A new type of imidazolium salt-modified porous hypercrosslinked polymer (BET surface area up to 926 m2 g-1) was reported. These porous materials exhibited good CO2 capture capacities (14.5 wt%) and catalytic activities for the conversion of CO2 into various cyclic carbonates under metal-free conditions. The synergistic effect of CO2 capture and conversion was observed.
- Wang, Jinquan,Sng, Waihong,Yi, Guangshun,Zhang, Yugen
-
-
Read Online
- A novel and green method for the synthesis of ionic liquids using the corresponding acidic ionic liquid precursors and dialkyl carbonate
-
A novel and green method for the synthesis of dialkylimidazolium ionic liquids (ILs) has been developed. It was through a one-step alkylation of dialkyl carbonate with the corresponding acidic ionic liquid precursors (AILPs) prepared from the neutralization of imidazole derivatives with acids.
- Xiao, Wenjun,Wang, Xiaoxing,Chen, Qin,Wu, Tinghua,Wu, Ying,Dai, Lizong,Song, Chunshan
-
-
Read Online
- Electronic excitations in homopolyatomic bismuth cations: Spectroscopic measurements in molten salts and an ab initio CI-Singles study
-
The electronic excitations of the low-valence bismuth cluster cations Bi53+, Bi82+, and Bi95+ have been studied with experimental and theoretical techniques. The UV-visible spectra of the b
- Day, Graeme,Glaser, Rainer,Shimomura, Noriyuki,Takamuku, Atsushi,Ichikawa, Kazuhiko
-
-
Read Online
- METHOD FOR PRODUCING AMIDATE COMPOUND, AND AMIDATE COMPOUND
-
A method for producing an amidate compound represented by Formula (4), comprising reacting an iminium salt represented by Formula (1) and an organic compound represented by Formula (3), wherein Formulas (1), (3), and (4) are as defined in the description.
- -
-
-
- Characterizing Cation Chemistry for Anion Exchange Membranes - A Product Study of Benzylimidazolium Salt Decompositions in the Base
-
Imidazolium functionality has played a prominent role in research on anion exchange membranes for use in alkaline electrochemical devices. Base stability and degradation of these materials has been much studied, but in many instances, product pathways have not been thoroughly delineated. We report an NMR study of base-induced decomposition products from three benzylimidazolium salts bearing varying extents of methyl substitution on the imidazolium ring. The major products are consistent with a hydrolytic ring fragmentation pathway as the principal mode of decomposition. We observe several new products not previously reported in the literature on imidazolium salt degradation, including benzilic acid rearrangement products formally derived from intermediate 1,2-dicarbonyl compounds or their equivalents. However, the overall reactions are complex, the yields of observed products do not account for all consumed starting materials, and mechanistic ambiguities remain.
- Pellerite, Mark J.,Kaplun, Marina M.,Webb, Robert J.
-
p. 15486 - 15497
(2019/11/19)
-
- Novel: Cis -[(NHC)1(NHC)2(L)Cl]platinum(II) complexes-synthesis, structures, and anticancer activities
-
A general synthesis of novel platinum(ii) complexes bearing two different, cis-oriented, N-heterocyclic carbene (NHC) ligands is presented. Easily accessible cis-[PtII(NHC)(DMSO)] precursor complexes were converted to either cis-[PtII(NHC)2Cl2] complexes such as 5a and 5b, or to novel mixed cis-[PtII(NHC)1(NHC)2Cl2] complexes such as 5c-h by successive introduction of the individual carbene ligands. The 'symmetric' complexes 5a and 5b were also converted to cationic cis-[PtII(NHC)2(PPh3)Cl]+Cl- complexes 8a and 8b. The structures of the ten new complexes, comprising benzylated and alkylated imidazol-2-ylidene ligands, were analysed by 1H, 13C and 195Pt NMR spectroscopy and also by X-ray diffraction for 5a, 5d, 5h, and 8a. The neutral complexes 5 were cytotoxic against a panel of seven human cancer cell lines with IC50 values in the low micromolar range, while the cationic complexes 8 reached even nanomolar IC50 values. Complex 5h carrying the substitution pattern of the natural antitumoral agent Combretastatin A-4 showed a conspicuous specificity for cancer cell lines sensitive to this drug. In electrophoretic mobility shift assays, the cis-biscarbene complexes 5b and 8b led to an unwinding or aggregation of plasmid DNA, while the trans-biscarbene complex 1b showed no such effect.
- Rehm, Tobias,Rothemund, Matthias,Muenzner, Julienne K.,Noor, Awal,Kempe, Rhett,Schobert, Rainer
-
supporting information
p. 15390 - 15398
(2016/10/13)
-
- PHOTOBASE GENERATOR
-
There is provided a photobase generator and a photosensitive resin composition containing the photobase generator. The photobase generator includes an ammonium salt represented by general formula (1). In formula (1), R1 to R4 independently represent an alkyl group having 1 to 18 carbon atoms or Ar, wherein at least one of R1 to R4 represents Ar; Ar represents an aryl group having 6 to 14 carbon atoms (excluding carbon atoms contained in a substituent as mentioned below), wherein some of hydrogen atoms in the aryl group may be independently substituted by an alkyl group having 1 to 18 carbon atoms or the like; Y+ represents an ammonio group represented by general formula (2) or (3); and E represents a hydrogen atom or a group represented by general formula (5).
- -
-
Paragraph 0109
(2016/02/03)
-
- Expedient Mechanosynthesis of N,N-Dialkyl Imidazoliums and Silver(I)-Carbene Complexes in a Ball-Mill
-
The absence of solvent, associated with intensive mechanical agitation, allowed the first mechanosynthesis of high-value silver(I)-carbene complexes and the corresponding N,N-dialkylimidazolium precursors. This procedure gave outstanding results in terms of yield and reaction time, when compared to solution-based conditions previously described in literature, and was generalized to unprecedented compounds. Silver(I)-carbene complexes could either be obtained from N,N-dialkylimidazolium salts or directly from imidazole and alkyl halides in a one-pot two-step procedure without isolating the imidazolium intermediate. Additionally, an efficient one-pot three-step sequence, including imidazole alkylation, silver metalation, and transmetalation is reported. You only hit twice! Solvent-free mechanochemical conditions enabled the rapid synthesis of high-value N,N-dialkyl-substituted NHC silver(I) complexes and the corresponding N,N-dialkylimidazolium precursors. Mechano-metalation and transmetalation are performed in a highly user- and eco-friendly approach. By using this strategy, up to three consecutive chemical steps, leading to organometallic complexes, could be performed in a ball-mill with high efficiency.
- Beillard, Audrey,Golliard, Ethan,Gillet, Valentin,Bantreil, Xavier,Métro, Thomas-Xavier,Martinez, Jean,Lamaty, Frédéric
-
supporting information
p. 17614 - 17617
(2015/12/05)
-
- Chemical Detoxification of Organomercurials
-
Organomercurials including methylmercury are ubiquitous environmental pollutants and highly toxic to humans. Now it could be shown that N-methylimidazole based thiones/selones having an N-CH2CH2OH substituent are remarkably effective in detoxifying various organomercurials to produce less toxic HgE (E=S, Se) nanoparticles. Compounds lacking the N-CH2CH2OH substituent failed to produce HgE nanoparticles upon treatment with organomercurials, suggesting that this moiety plays a crucial role in the detoxification by facilitating the desulfurization and deselenization processes. This novel way of detoxifying organomercurials may lead to the discovery of new compounds to treat patients suffering from methylmercury poisoning. Getting rid of mercury: Insoluble HgE (E=S, Se) nanoparticles (NPs) are formed under physiologically relevant conditions when organomercurials are treated with N-methylimidazole-based thiones/selones having an N-CH2CH2OH substituent. Compounds lacking the N-CH2CH2OH substituent failed to produce HgE NPs upon treatment with organomercurials under identical reaction conditions. A novel pathway of detoxifying various organomercurials is described.
- Banerjee, Mainak,Karri, Ramesh,Rawat, Kuber Singh,Muthuvel, Karthick,Pathak, Biswarup,Roy, Gouriprasanna
-
supporting information
p. 9323 - 9327
(2015/08/06)
-
- Polystyrene-supported N-heterocyclic carbene-silver complexes as robust and efficient catalysts for the reaction of carbon dioxide and propargylic alcohols
-
Three polystyrene-supported N-heterocyclic carbene-silver complexes [PS-NHC-Ag(I)] and a polystyrene-supported N-heterocyclic carbene-copper complex [PS-NHC-Cu(I)] catalyst were synthesized and characterized by elemental analysis, Fourier transform infrared spectroscopy, inductively coupled plasma-atom emission spectrometer, thermogravimetric analysis and scanning electron micrographs. The catalytic activity of the supported catalysts was investigated for the reaction of propargylic alcohols and carbon dioxide. PS-NHC-Cu(I) showed no catalytic activity to the reaction, while PS-NHC-Ag(I) showed a considerable high activity and selectivity for the reaction, yielding the corresponding α-alkylidene cyclic carbonates in high to excellent yields under mild conditions. Most importantly, the supported catalysts could be separated easily from the products and reused up to 15 times without loss of their high catalytic activity, showing excellent stability. The effect of various reaction parameters such as carbon dioxide pressure, temperature, time, and catalyst loading on the reaction was also investigated. Copyright
- Tang, Xiaodong,Qi, Chaorong,He, Haitao,Jiang, Huanfeng,Ren, Yanwei,Yuan, Gaoqing
-
supporting information
p. 2019 - 2028
(2013/08/23)
-
- Densities and viscosities of imidazolium and pyridinium chloroaluminate ionic liquids
-
The chloroaluminate ionic liquids are used in various types of reactions. However, due to their particular vulnerability on water, their physical properties have not been previously investigated very extensively. The densities and viscosities of series imidazolium and pyridinium chloroaluminate ionic liquids having alkyl (butyl, hexyl, octyl) or aralkyl (benzyl, ethylphenyl) chain at the cation, various effective molar fraction of AlCl3 (χAlCl3 = 0.5, 0.65, 0.7), as well as they mixture and mixture with common organic solvents (hexane, toluene) were measured at the temperature range 293.15-343.15 K (20-70 °C). Densities, and particularly viscosities decrease with the increase of temperature. The density decreases with the increase of the length of the alkyl chain. The type of cation also influences the density, however, the order is different than for non-haloaluminate ionic liquids and depends on the alkyl chain length. Viscosity increases with increasing alkyl chain length, but it is not a linear trend. The ionic liquid with meta position of the alkyl chain is considerably more dense and more viscous than para isomer. The presence of aromatic phenyl ring at the side chain of the cation increases both density and viscosity. Higher effective molar fraction of AlCl3 increases density and decreases viscosity, however, for the imidazolium ionic liquid the change of viscosity diminishes at higher temperatures. Organic solvents decrease both density and viscosity of the ionic liquids, but aliphatic hexane imposes much smaller effect than aromatic toluene. The mixture of two ionic liquids has density and viscosity between those for constituents. This extends the application of the aralkyl ionic liquids over temperatures, in which they are in solid state.
- Och?dzan-Siod?ak, Wioletta,Dziubek, Katarzyna,Siod?ak, Dawid
-
-
- One-pot synthesis of 3-substituted indole derivatives using moisture stable, reusable, and task specific ionic liquid catalysts
-
Moisture stable Broensted acidic (BIL) and Lewis acidic ionic liquid catalysts have been synthesized and their catalytic activities have been examined in the synthesis of biologically important indole-3-derivatives. Catalytic activities of these ionic liquid catalysts have been investigated for some important catalytic reactions such as three component coupling reaction of benzaldehyde, N-methylaniline and indole and Michael addition reaction of indole with β- nitrostyrene/chalcone/acetyl acetone. In all these reactions, BIL functionalized with sulfonic acid is found to be the best task specific catalyst. BILs are inexpensive and easy to synthesize, and can be separated easily and reused for three cycles without significant loss in catalytic activity. Catalyst offers several attractive features such as low cost, high catalytic activity/selectivity and recyclability.
- Ravindran, Anaswara,Kore, Rajkumar,Srivastava, Rajendra
-
p. 129 - 135
(2013/02/25)
-
- A simple, eco-friendly, and recyclable bi-functional acidic ionic liquid catalysts for Beckmann rearrangement
-
A library of ionic liquids was prepared by varying the cations and anions. Bi-functional acidic ionic liquids were prepared by the direct combination of ionic liquids and ZnCl2. Ionic liquids were investigated in the Beckmann rearrangements. A simple, eco-friendly, and recyclable bi-functional acidic ionic liquid based protocol for Beckmann rearrangement is developed, which is based on the fine tuning of the Br?nsted and the Lewis acidity of ionic liquids.
- Kore, Rajkumar,Srivastava, Rajendra
-
-
- Parallel microwave-assisted synthesis of ionic liquids and screening for denitrogenation of straight-run diesel feed by liquid-liquid extraction
-
Fifty-six ionic liquids were efficiently synthesized in parallel format under one-pot, solvent-free microwaveassisted synthesis. These compounds were evaluated as extracting agents of nitrogen-containing compounds from a real Diesel feed before being submitted to the hydrodesulfurization process to obtain ultralow sulfur Diesel. Our results showed that halogenated ionic liquids are an excellent alternative due to these ionic liquids are relatively inexpensive, presenting a high selectivity for the extraction of nitrogen-containing compounds and can be regenerated and recycled.
- Ceron, Miguel A.,Guzman-Lucero, Diego J.,Palomeque, Jorge F.,Martinez-Palou, Rafael
-
experimental part
p. 427 - 432
(2012/07/01)
-
- Influence of -SO3H functionalization (N-SO3H or N-R-SO3H, where R = alkyl/benzyl) on the activity of Br?nsted acidic ionic liquids in the hydration reaction
-
Sulfonic acid group functionalized imidazole based Br?nsted acidic ionic liquids (BAILs) were synthesized and their activities were investigated in the hydration reaction of alkynes. The Hammett acidity order determined from UV-visible spectroscopy of BAILs is consistent with their activity order observed in hydration reactions. Theoretical studies further help to establish the structure-activity relationship. Recycling experiments suggest that these novel BAILs can be reused without significant loss in activity. Applicability of BAILs in hydration reaction opens a non-toxic, economical, and eco-friendly route to synthesize alkyl ketones from alkynes.
- Kore, Rajkumar,Srivastava, Rajendra
-
scheme or table
p. 3245 - 3249
(2012/07/31)
-
- Hydration of alkynes using Br?nsted acidic ionic liquids in the absence of Nobel metal catalyst/H2SO4
-
In this study, a variety of imidazole based sulfonic acid group functionalized Br?nsted acidic ionic liquids (BAILs) were synthesized. BAILs have been successfully developed as task specific ionic liquids for hydration of alkynes under mild conditions to give high yields of ketones as a selective product. Acidity of BAILs was determined using volumetric titration and UV-visible spectroscopic methods. The Hammett acidity order and acid value of BAILs correlate well with the activity order observed for most of the BAILs in the hydration reaction of phenylacetylene. Theoretical studies demonstrate that hydrogen bonding plays a key role in tuning the acidity of BAILs. Density function theory calculations are also able to explain the difference in activity observed in these BAILs. The activity of ionic liquids was theoretically studied by computing the activation energy for the hydration reaction. Recycling experiments suggest that these novel BAILs can be reused without significant loss in activity. BAILs are simple and easy to prepare and exhibit excellent activity toward the hydration of a variety of alkynes to ketones. Moreover, the reaction involving BAILs does not involve heavy metal catalysts or H 2SO4. Novel BAILs offer several attractive features such as sustainable synthetic route, low cost, moisture stability, high yields, and recyclability.
- Kore, Rajkumar,Kumar, T.J. Dhilip,Srivastava, Rajendra
-
scheme or table
p. 61 - 70
(2012/08/14)
-
- Syntheses and catalytic activities of homogenous and hierarchical ZSM-5 grafted Pd(II) dicarbene complex of imidazole based ionic liquids
-
Pd(II) dicarbene complex of imidazole based cyclic and acyclic ionic liquids were prepared and their catalytic activities were compared in the Heck and the Sonogashira reactions of deactivated and economical bromobenzene/ chlorobenzene. Acyclic Pd complex was found to be more active than the cyclic one. Geometrically optimized structures of cyclic and acyclic Pd complexes, which was computed using density functional method was able to explain the low activity of cyclic Pd complex. Further, these catalysts were grafted on hierarchical ZSM-5 surface and their catalytic activity and recyclability were investigated. Pd(II) dicarbene complex grafted on hierarchical ZSM-5 were found to be efficient and recyclable catalysts for CC coupling reactions. Catalysts were found to be stable and show negligible loss in activity even after the five cycles.
- Kore, Rajkumar,Tumma, Mahesh,Srivastava, Rajendra
-
supporting information
p. 189 - 196
(2013/01/15)
-
- Thermal stability of 1,3-disubstituted imidazolium tetrachloroferrates, magnetic ionic liquids
-
Thermal stability of synthesized magnetic liquids, tetrachloroferrates of 1,3-disubstitued derivatives of imidazolium, was examined. An effect of the cation structure on thermal stability of ionic liquids was considered and a mechanism of thermal destruction was suggested.
- Zhuravlev,Verolainen,Voronchikhina
-
experimental part
p. 1158 - 1164
(2011/11/30)
-
- Synthesis of 2-imidazolones and 2-iminoimidazoles
-
Convenient methods for the direct conversion of imidazolium salts to the corresponding 2-imidazolone or 2-imino imidazole derivatives have been developed. Treatment of the salt with commercial bleach leads to effective oxidation at C2 and the formation of the corresponding imidazolone. Alternatively, treatment of the salt with an N-chloro amide affords the corresponding protected 2-amino derivative in good yield.
- Lima, Heather M.,Lovely, Carl J.
-
supporting information; experimental part
p. 5736 - 5739
(2011/12/05)
-
- Synthesis and applications of novel imidazole and benzimidazole based sulfonic acid group functionalized Broensted acidic ionic liquid catalysts
-
In this study, a variety of imidazole/benzimidazole based sulfonic acid group functionalized Broensted acidic ionic liquids (BAILs) were synthesized. Catalytic activities of BAILs were assessed using multi-component coupling reactions. Catalytic activities of BAILs were high when compared with those of solid acid catalysts such as H-ZSM-5, H-BETA, and sulfonic acid functionalized SBA-15 catalysts. The Hammett acidity order determined from UV-visible spectroscopy of BAILs is consistent with their activity order observed in acid-catalyzed reactions. Theoretical studies demonstrate that the hydrogen bonding plays a key role in tuning the acidity of BAILs. Recycling experiments suggest that these novel BAILs can be reused without significant loss in catalytic activity. Novel BAILs offer several attractive features such as low cost, high catalytic activity, and recyclability.
- Kore, Rajkumar,Srivastava, Rajendra
-
scheme or table
p. 117 - 126
(2011/10/05)
-
- Synthesis and applications of highly efficient, reusable, sulfonic acid group functionalized Broensted acidic ionic liquid catalysts
-
A variety of sulfonic acid group functionalized Broensted acidic ionic liquids (BAILs) catalysts were synthesized. Catalytic activities of BAILs were assessed using condensation and esterification reactions. Catalytic activities of BAILs were high when compared with H-ZSM-5, H-BETA, sulfonic acid functionalized SBA-15 catalyst. The Hammett acidity order determined from UV-visible spectroscopy of BAILs is consistent with their activity order observed in acid-catalyzed reactions. Recycling experiments suggests that these novel BAILs can be reused without significant loss in catalytic activity. Novel BAILs offers several attractive features such as low cost, high catalytic activity and recyclability.
- Kore, Rajkumar,Srivastava, Rajendra
-
scheme or table
p. 1420 - 1424
(2012/07/31)
-
- Assessment of the catalytic activities of novel broensted acidic ionic liquid catalysts
-
Broensted acidic ionic liquids (BILs) were synthesized by a two step synthetic protocol. Catalytic activities of BILs were assessed by means of suitable catalytic reactions such as acylation of 2-methoxynapthalene with acetic anhydride, Biginelli reaction to synthesize 3,4-dihydropyrimidin-2(1H)- one, stereoselective synthesis of β-amino ketone via direct Mannich-type reaction and esterification of hexanoic acid with benzyl alcohol. Catalytic activities of BILs were high when compared with those of solid acid catalysts such as ZSM-5, beta, dealuminated beta and Al-SBA-15. BILs catalysts were found to be highly stereo/regio-selective for above mentioned reactions. Novel BILs catalyst offers several attractive features such as low cost, high catalytic activity/selectivity and recyclability. Graphical Abstract: N-methylimidazole and pyridine derived Broensted acidic ionic liquids were found to be highly active and stereo/regio-selective compared to various solid acid catalysts in fine chemicals (1-5) synthesis.[Figure not available: see fulltext.]
- Srivastava, Rajendra
-
experimental part
p. 17 - 25
(2010/12/25)
-
- Ultrasound-assisted solvent-free synthesis of lactic acid esters in novel SO3H-functionalized Br?nsted acidic ionic liquids
-
Mild and efficient Fischer esterification reactions of lactic acid with a variety of straight chain aliphatic alcohols, cyclohexanol and benzyl alcohol were successfully performed using two novel Br?nsted acidic ionic liquids that bear an aromatic sulfonic acid group on the imidazolium or pyridinium cation under ultrasound irradiation. These reactions carried out smoothly with good to excellent conversion rate (78-96%) and satisfactory yields (73-92%) in shorter reaction time (4-6 h) at room temperature when the amount of ionic liquids was 20 mol%. These ionic liquids could be recovered readily and recycled five times without any significant loss in their catalytic activity.
- Li, Xinzhong,Lin, Qi,Ma, Liang
-
scheme or table
p. 752 - 755
(2011/10/08)
-
- Effect of ionic liquids on the Menschutkin reaction: An experimental and theoretical study
-
(Figure Presented) The effect of ionic liquids (ILs) on the Menschutkin reaction between N-methylimidazole and benzyl halides has been investigated. Hammett correlations have been used to obtain information on the reaction mechanism of benzyl chlorides in
- Bini, Riccardo,Chiappe, Cinzia,Pomelli, Christian Silvio,Parisi, Benedetta
-
experimental part
p. 8522 - 8530
(2010/01/19)
-
- Influence of different branched alkyl side chains on the properties of imidazolium-based ionic liquids
-
Several new branched ionic liquids were synthesized under microwave irradiation applying two different synthetic approaches. Different already known ionic liquids, both linear and branched, were added to this set of new ionic liquids to investigate the influence of the branching on the thermophysical properties to elucidate first structure-property relationships. Thermogravimetric analysis was utilized to investigate the decomposition behavior and differential scanning calorimetry was used to study the influence of the branching on the thermal behavior, e.g. the melting point, the glass transition temperature, the freezing point and the cold crystallization temperature. Moreover, the water uptake of selected ionic liquids was analyzed. The Royal Society of Chemistry 2008.
- Erdmenger, Tina,Vitz, Juergen,Wiesbrock, Frank,Schubert, Ulrich S.
-
supporting information; experimental part
p. 5267 - 5273
(2010/03/24)
-
- Dissolution of wood in ionic liquids
-
The present paper demonstrates that both hardwoods and softwoods are readily soluble in various imidazolium-based ionic liquids (ILs) under gentle conditions. More specifically, a variety of ionic liquids can only partially dissolve wood chips, whereas ionic liquids such as 1-butyl-3-methylimidazolium chloride and 1-allyl-3-methylimidazolium chloride have good solvating power for Norway spruce sawdust and Norway spruce and Southern pine thermomechanical pulp (TMP) fibers. Despite the fact that the obtained solutions were not fully clear, these ionic liquids provided solutions which permitted the complete acetylation of the wood. Alternatively, transparent amber solutions of wood could be obtained when the dissolution of the same lignocellulosic samples was attempted in 1-benzyl-3-methylimidazolium chloride. This realization was based on a designed augmented interaction of the aromatic character of the cation of the ionic liquid with the lignin in the wood. After dissolution, wood can be regenerated as an amorphous mixture of its original components. The cellulose of the regenerated wood can be efficiently digested to glucose by a cellulase enzymatic hydrolysis treatment. Furthermore, completely acetylated wood was found to be readily soluble in chloroform, allowing, for the first time, detailed proton nuclear magnetic resonance (NMR) spectra and NMR diffusion measurements to be made. It was thus demonstrated that the dissolution of wood in ionic liquids now offers a variety of new possibilities for its structural and macromolecular characterization, without the prior isolation of its individual components. Furthermore, considering the relatively wide solubility and compatibility of ionic liquids with many organic or inorganic functional chemicals or polymers, it is envisaged that this research could create a variety of new strategies for converting abundant woody biomass to valuable biofuels, chemicals, and novel functional composite biomaterials.
- Kilpelaeinen, Ilkka,Xie, Haibo,King, Alistair,Granstrom, Mari,Heikkinen, Sami,Argyropoulos, Dimitris S.
-
experimental part
p. 9142 - 9148
(2009/09/25)
-
- Nanohybrid materials from the intercalation of imidazolium ionic liquids in kaolinite
-
A series of novel organic-inorganic nanohybrid materials were obtained by the intercalation in the interlamellar spaces of the clay mineral kaolinite, of ionic liquids based on imidazolium derivatives. The intercalation procedure was successfully accomplished via a melt reaction strategy using the dimethylsulfoxide-kaolinite intercalate (DMSO-K) as a precursor. 13C MAS NMR as well as XRD, TGA/DTA and FTIR studies confirmed the complete displacement of DMSO molecules by the imidazolium salts during the intercalation process. Increase of the basal spacing from 1.1 nm in DMSO-K to 1.3-1.7 nm in the nanohybrid materials was observed, indicating that imidazolium derivatives are oriented in a way such that the imidazole ring is parallel, or slightly tilted by an angle of 10-25°, with respect to the kaolinite internal surfaces. The number of moles of organic material loaded in the nanohybrids was obtained from several independent measurements. The intercalation of the imidazolium salts increases the thermal stability of the resulting material by more than 150 °C with respect to DMSO-K. After heating under air at 300 °C for two hours, XRD showed that the structure of the intercalates was kept with only a slight decrease of the intercalation ratio. The original kaolinite structure was recovered after heating the intercalate at 350 °C for an additional two hours. This observed high thermal stability is promising for the use of these nanohybrid materials as precursor for the synthesis of new nanocomposites by incorporation of polymer in kaolinite at high temperature. The Royal Society of Chemistry.
- Letaief, Sadok,Detellier, Christian
-
p. 1476 - 1484
(2008/02/04)
-
- 14N NMR and two-dimensional suspension 1H and 13C HAMAS NMR spectroscopy of ionic liquids immobilized on silica
-
A variety of popular ionic liquids have been synthesized and characterized, including by optimized 14N NMR spectroscopy of the neat and dissolved ionic liquids. Ionic liquids incorporating Si(OEt)3 groups have been immobilized on silica in a well-defined manner with the imidazolium moiety remaining intact. This has been proved by optimized one- and two-dimensional 1H and 13C HRMAS NMR spectroscopy of the materials suspended in suitable solvents.
- Brenna, Stefano,Posset, Tobias,Furrer, Julien,Bluemel, Janet
-
p. 2880 - 2888
(2008/02/03)
-