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1.
Ionic liquid glow discharge electrolysis for nanoparticle synthesis is an emerging nanomaterials processing technology and the stability of ionic liquid when they are in contact with plasma is an important issue. This paper discusses the stability of [BMIM][BF4] after exposing this ionic liquid to glow discharge plasma and the synthesis of cubic crystalline ZnS nanoparticles by plasma electrochemical method. Stability of the ionic liquid after plasma exposure to 20 min at 250 V is explained by their FTIR spectra and found that the ionic liquid is stable even after the plasma exposure. 相似文献
2.
The methodology of using a silica gel-supported functionalized ionic liquid as a scavenger in the purification of parallel
synthesis products was demonstrated. Silica-supported sulfonic acid-functional ionic liquid was synthesized by etherification,
aminate, and quaternary aminate from activated silica gel and 3-chloropropyl trimethoxysilane, imidazole, and 1,4-butanesultone,
which was followed by acidification using trifluoromethanesulfonic acid and anion exchange with potassium hexafluorophosphate.
A conventional ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate was then used to coat the surface of the silica
gel. The silica-supported functionalized ionic liquid was used as a scavenger in the removal of excess amine in the parallel
synthesis of amides. Desired products were obtained in excellent yields and purity with a sequestration time of less than
100 min at room temperature. After scavenging, the scavenger was easily filtered out and regenerated. 相似文献
3.
Alexandra Wittmar David Ruiz-Abad Mathias Ulbricht 《Journal of nanoparticle research》2012,14(2):651-10
The colloidal stabilities of dispersions of unmodified and surface-functionalized SiO2 nanoparticles in hydrophobic and hydrophilic imidazolium-based ionic liquids were studied with advanced rheology at three
temperatures (25, 100, and 200 °C). The rheological behavior of the dispersions was strongly affected by the ionic liquids
hydrophilicity, by the nanoparticles surface, by the concentration of the nanoparticles in the dispersion as well as by the
temperature. The unmodified hydrophilic nanoparticles showed a better compatibility with the hydrophilic ionic liquid. The
SiO2 surface functionalization with hydrophobic groups clearly improved the colloidal stability of the dispersions in the hydrophobic
ionic liquid. The temperature increase was found to lead to a destabilization in all studied systems, especially at higher
concentrations. The results of this study imply that ionic liquids with tailored properties could be used in absorbers directly
after reactors for gas-phase synthesis of nanoparticles or/and as solvents for their further surface functionalization without
agglomeration or aggregation. 相似文献
4.
The combined effect of ultrasounds and ionic liquids was used to perform the synthesis of aryl azides by nucleophilic aromatic substitution in ionic liquid/[1-butyl-3-methylimidazolium][N3] binary mixtures. The ultrasounds efficiency was analyzed as a function of the substrate and of the ionic liquid structure. In the first case, both 6π and 10π electrons aryl halides were considered. As far as the ionic liquid structure is concerned, both aromatic and aliphatic ionic liquids were taken into account. Among aromatic cations, the effects due to different ability in giving hydrogen bond or π-π interactions were considered. The use of a geminal ionic liquid having an aromatic spacer was examined too.On the whole, collected data evidence an activating effect on the target reaction by the combined use of ultrasounds and ionic liquids. The structural order degree of the ionic liquid seems to be the main factor affecting the ultrasounds efficiency. Furthermore, the effects due to changes in the anion structure seem to be more significant than those due to changes in the cation structure. 相似文献
5.
T. Wöhrle P. Gómez-Romero T. Fries K. West M. R. Palacín N. Casañ-Pastor 《Ionics》1996,2(5-6):442-445
The lithium ionic conducting perovskite La0.57Li0.3TiO3 has been synthesised via a sol-gel method at a temperature of 700 °C. The crystallinity of the product can be greatly increased
by further heat treatment at 1000 °C. In this paper the product of the sol-gel synthesis is compared with the product of conventional
solid-state synthesis, and the influence of the synthesis method as well as of quenching on the crystal structure and ionic
conductivity has been studied. AC-impedance measurements show two contributions to the ionic conductivity, which can be adscribed
to intergranular and intragranular effects, respectively. A lower intergranular resistivity is observed for sol-gel samples,
while quenching mainly affects the materials prepared by solid-state reaction. The crystal structure of the material prepared
by the sol-gel method is identical to that of the material prepared by the solid state reaction, although the synthesis temperature
is nearly 600 °C lower. A tetragonal superstructure is observed when either type of material is slowly cooled from 1300 °C.
Quenching from the same temperature results in the suppression of that superstructure.
Paper presented at the 3rd Euroconference on Solid State Ionics, Teulada, Sardinia, Italy, Sept. 15–22, 1996 相似文献
6.
Dehshahri Ali Sadeghpour Hossein Kazemi Oskuee Reza Fadaei Mahin Sabahi Zahra Alhashemi Samira Hossaini Mohazabieh Erfaneh 《Journal of nanoparticle research》2014,16(5):1-14
The influence of the hydrophilicity and length of the cation alkyl chain in imidazolium-based ionic liquids on the dispersability of ZnO nanoparticles by ultrasound treatment was studied by dynamic light scattering and advanced rheology. ZnO nanopowder synthesized by chemical vapor synthesis was used in parallel with one commercially available material. Before preparation of the dispersion, the nanoparticles characteristics were determined by transmission electron microscopy, X-ray diffraction, nitrogen adsorption with BET analysis, and FT-IR spectroscopy. Hydrophilic ionic liquids dispersed all studied nanopowders better and in the series of hydrophilic ionic liquids, an improvement of the dispersion quality with increasing length of the alkyl chain of the cation was observed. Especially, for ionic liquids with short alkyl chain, additional factors like nanoparticle concentration in the dispersion and the period of the ultrasonic treatment had significant influence on the dispersion quality. Additionally, nanopowder characteristics (crystallite shape and size as well as the agglomeration level) influenced the dispersion quality. The results indicate that the studied ionic liquids are promising candidates for absorber media at the end of the gas phase synthesis reactor allowing the direct preparation of non-agglomerated nanoparticle dispersions without supplementary addition of dispersants and stabilizers. 相似文献
7.
Qiang Zhang Fangjun Liu Liang Li Guoliang Pan Songmin Shang 《Journal of nanoparticle research》2011,13(1):415-421
A simple strategy for the one-step synthesis of polyaniline/AgCl nanocomposites at the water/magnetic ionic liquid interface was reported. By controlling the reactive conditions, highly dispersed polyaniline/AgCl nanocomposites with their size ranging around 50–80 nm were obtained with magnetic ionic liquid as the oxidant. Transmission electron microscopy was used to show the morphology of the nanocomposites. The nanocomposites were also characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. Moreover, polyaniline/AgCl nanocomposites on a glassy carbon electrode showed strong electrocatalytic activity for H2O2 and could be used to construct a H2O2 biosensor. 相似文献
8.
Qiang Zhang Fangjun Liu Liang Li Guoliang Pan Songmin Shang 《Journal of nanoparticle research》2011,13(1):423-421
A simple strategy for the one-step synthesis of polyaniline/AgCl nanocomposites at the water/magnetic ionic liquid interface
was reported. By controlling the reactive conditions, highly dispersed polyaniline/AgCl nanocomposites with their size ranging
around 50–80 nm were obtained with magnetic ionic liquid as the oxidant. Transmission electron microscopy was used to show
the morphology of the nanocomposites. The nanocomposites were also characterized by Fourier transform infrared spectroscopy,
X-ray diffraction, and thermogravimetric analysis. Moreover, polyaniline/AgCl nanocomposites on a glassy carbon electrode
showed strong electrocatalytic activity for H2O2 and could be used to construct a H2O2 biosensor. 相似文献
9.
Synthesis and application of task-specific ionic liquids used as catalysts and/or solvents in organic unit reactions 总被引:1,自引:0,他引:1
This paper took various types of the task-specific ionic liquids as the main to review their synthesis and application to organic unit reactions from the point of view of development and practical utility. The economical task-specific ionic liquids were also brought forward. 相似文献
10.
Xinying Zhang Xiaoyan Li Xuesen Fan Xia Wang Dongfang Li Guirong Qu Jianji Wang 《Molecular diversity》2009,13(1):57-61
One-pot multi-component reactions of aldehydes, cyanothioacetamide and malononitrile promoted by ionic liquid proved to be
an efficient way for the synthesis of thiopyran derivatives. Without any added catalyst, both aromatic and aliphatic aldehydes
participated in this reaction smoothly. As an application of this method, a pyrimidine nucleoside-thiopyran chimera with potential
biological activities was obtained in high yield from 5-formyl-2’-deoxyuridine. In addition, the ionic liquid used can be
easily recovered and effectively reused for at least 5 times.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
11.
Yimei Tang Xiaoling Hu Ping Guan Xiangping Lin Xiaoqian Li 《Journal of Physical Organic Chemistry》2014,27(6):498-503
Using microwave‐assisted synthesis method, a series of paramagnetic ionic liquids comprising 1‐vinyl‐3‐alkylimidazolium VRIM+ cation and tetrahalogenidoferrate (III) FeClmBr4 ? m? anion were designed and synthesized. The structure was analyzed using 1H NMR and Raman spectroscopy. Ultraviolet–visible absorption spectra, thermal stability, magnetic susceptibility, viscosity, ionic conductivity, and solubility were characterized. Results show that elongation of the alkyl chain leads to replacement of bromides with a small amount of chlorides in the anion, shifting of UV maximum absorption peaks to shorter wavelengths, reduction of ionic conductivity, and solubility in polar solvents, as well as increase in fluidity, magnetic susceptibility, and solubility in nonpolar solvents. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
Guo Hongxu Ke Yingchang Wang Dongfeng Lin Kaili Shen Ruxiang Chen Jianhua Weng Wen 《Journal of nanoparticle research》2013,15(3):1-12
The influence of the length of the cation alkyl chain on the dispersibility by ultrasonic treatment of TiO2 nanopowders in hydrophilic imidazolium-based room temperature ionic liquids was studied for the first time by dynamic light scattering and advanced rheology. TiO2 nanopowders had been synthesized by chemical vapor synthesis (CVS) under varied conditions leading to two different materials. A commercial nanopowder had been used for comparison. Characterizations had been done using transmission electron microscopy, X-ray diffraction, nitrogen adsorption with BET analysis, and FT-IR spectroscopy. Primary particle sizes were about 6 and 8 nm for the CVS-based and 26 nm for the commercial materials. The particle size distribution in the dispersion was strongly influenced by the length of the cation alkyl chain for all the investigated powders with different structural characteristics and concentrations in the dispersion. It was found that an increase of the alkyl chain length was beneficial, leading to a narrowing of the particle size distribution and a decrease of the agglomerate size in dispersion. The smallest average nanoparticle sizes in dispersion were around 30 nm. Additionally, the surface functionality of the nanoparticles, the concentration of the solid material in the liquid, and the period of ultrasonic treatment control the dispersion quality, especially in the case of the ionic liquids with the shorter alkyl chain. The influence of the nanopowders characteristics on their dispersibility decreases considerably with increasing cation alkyl chain length. The results indicate that ionic liquids with adapted structure are candidates as absorber media for nanoparticles synthesized in gas phase processes to obtain liquid dispersions directly without redispergation. 相似文献
13.
We report the synthesis of a new series of imidazolium-based halogen-free ionic liquids 1-alkyl-3-methylimidazolium lauryl
sulfates. By reacting 1-methylimidazole (MIM) with butyl, hexyl, octyl, and decyl bromides and exchanging bromide ion with
lauryl sulfate anion, a series of ionic liquids [RMIM][C12H25OSO3] were produced. The high purity of these ionic liquids was verified with 1H-NMR, 13C-NMR, FT-IR and mass spectrometry (MS), demonstrating the effectiveness of this synthetic approach. Solubility test of these
ionic liquids showed that they are soluble in most organic solvents except nonpolar solvents such as hexane and cyclohexane.
The optical properties of [BMIM]Br and [BMIM][C12H25OSO3], where B refers to butyl, were examined. Both ionic liquids absorbed light in the UV region, yet essentially no absorption
was recorded beyond 450 nm. Furthermore, both ionic liquids showed excitation wavelength-dependent fluorescence behavior.
As an example, with an excitation wavelength of 360 nm, [BMIM][C12H25OSO3] showed an emission band maximum at 447 nm. Increasing the excitation wavelength to 440 nm, the emission band maximum was
shifted to ∼500 nm. 相似文献
14.
H2O2 mediated oxidation of alcohols in ionic liquid is revisited, wherein, ionic liquids under the influence of microwave irradiation
have been found to facilitate activation of H2O2 without any metal catalyst in aqueous condition. The method utilizes a neutral ionic liquid [hmim]Br both as catalyst and
solvent for efficient and chemoselective oxidation of benzyl alcohol derivatives on aromatic (β, γ) alcohols, cyclic and aliphatic analogues, which can be a useful synthetic approach in total synthesis of complex organic
compounds/natural products. Moreover, an unexpected oxidation of 9-anthracenyl propanol, a polyaromatic benzyl alcohol, resulting
in the formation of 9,10-anthraquinone by the loss of propyl side chain was observed. Plausible mechanism and further exploration
of this method on various other related substrates are discussed in detail. 相似文献
15.
An efficient and facile process to synthesize mandelic acid through phase transfer catalysis (PTC; also phase transfer catalyst) using ultrasound in an ionic liquid has been developed. Mandelic acid was synthesized from benzaldehyde with chloroform in an 89.6% yield at 60°C for 2h by using tetrabutyl ammonium bromide (TBAB) as a phase transfer catalyst. Effects of different factors, such as frequency of ultrasound, reaction temperature, kinds of PTC and solvents had been investigated to obtain the optimum condition. It was observed that the ultrasonically promoted synthesis of mandelic acid by PTC in the ionic liquid exhibited significant enhancement in reaction yields under ambient conditions. 相似文献
16.
Víctor Hugo Álvarez Diego Serrão Júlio Lopes da Silva Jr. Mariana Ricken Barbosa Martín Aznar 《Ionics》2013,19(9):1263-1269
This study reports the synthesis of a new protic ionic liquid, bis(2-hydroxyethyl)ammonium butyrate (2-HE2AB), performed by a Brønsted acid–base reaction between butanoic acid and bis(2-hydroxyethyl)ammonia. The new ionic liquid was characterized by 1D hydrogen NMR spectrum. The ionic liquid shows complete solubility in water, methanol, and ethanol, and is partially soluble in methyl acetate, ethyl acetate, and propyl acetate, while it is not soluble in some alkanes. Density, refractive index, and vapor–liquid equilibrium were measured for the binary system 2-HE2AB + methyl acetate at atmospheric pressure. Furthermore, density, refractive index, and liquid–liquid equilibrium were measured for the binary systems 2-HE2AB + ester (methyl acetate, ethyl acetate, or propyl acetate) at 293.2 K. The Peng-Robinson equation of state, coupled with the Wong-Sandler mixing rule, was used in the thermodynamic modeling of density, vapor–liquid, and liquid–liquid equilibrium data. The COSMO-SAC activity coefficient model was used to calculate the activity coefficient within the Wong-Sandler mixing rule. The calculations show deviations for density, for the vapor–liquid equilibrium, and for the non-polar and polar phases of the liquid–liquid equilibrium within 13.0, 0.1, 132.5, and 23.8 %, respectively. 相似文献
17.
A family of novel ionic liquid with l-alanine and choline chloride as environmentally benign materials have been synthesized and grafted on Fe3O4 nanoparticles using easy preparation techniques. The structure of ionic liquid supported on Fe3O4 nanoparticles (IL-Fe3O4 NPs) characterized by various analyses such as FE-SEM, EDX, XRD, NMR, FTIR and VSM. The catalytic activities of this catalyst are examined in the Mannich reaction for synthesis of β-aminocarbonyl compounds under ultrasonic irradiation. The recyclability of catalyst is investigated, and the results have indicated that the catalyst can be recycled six times without obvious activity decreasing. 相似文献
18.
A novel multicomponent reaction between IL-anchored 2-aminobenzoimidazoles, aldehydes, and electron-deficient dienophiles has been explored. The strategy was utilized to develop a rapid parallel synthesis for novel bis-heterocyclic skeleton of benzimidazole-linked dihydropyrimidine on an ionic liquid support. This multicomponent reaction is compatible with a wide range of substrates and furnishes the new chimeric scaffolds with high purity and excellent yields. Use of the ionic liquid as a soluble support facilitates purification by simple precipitation along with advantages like high loading capacity, homogeneous reaction conditions, and monitoring of the reaction progress by conventional NMR spectroscopy. 相似文献
19.
Natalya V. Likhanova Diego Guzmán-Lucero Eugenio A. Flores Paloma García Marco A. Domínguez-Aguilar Jorge Palomeque Rafael Martínez-Palou 《Molecular diversity》2010,14(4):777-787
Seventy five ionic liquids (ILs) were tested as a sequestering agent of sulfured compounds in natural gasoline (NG). Desulphurization
of NG was performed by means of liquid–liquid extraction method at room temperature and atmospheric pressure. Experimental
ILs containing imidazolium, pyridinium, and ammonium cations along with organic and inorganic anions were synthesized conventionally
and under microwave and sonochemical conditions. The effect of the molecular structure of ILs on the desulfurization efficiency
of NG with high sulfur content was evaluated. Analysis indicated that the anion type played a more important role than the
cation on the desulphurization process. ILs based on halogen–ferrates and halogen–aluminates exhibited the highest efficiency
in sulfur removal, and their efficiency is further improved when there is an excess of metallic salt in a ratio of at least
1:1.3 during the synthesis of the corresponding IL. An explanation for the ability of metallic ILs to remove sulfur-containing
compounds from natural gasoline based on the ratio of the ionic charge to the atomic radius is proposed. Furthermore, a method
to recover and reuse water-sensitive to halogenated precursors is described. 相似文献
20.
P. Rosaiah P. Jeevan Kumar K. Jayanth Babu O. M. Hussain 《Applied Physics A: Materials Science & Processing》2013,113(3):603-611
Lithium iron phosphate (LiFePO4) cathode material has been prepared by hydrothermal synthesis. The XRD spectrum exhibited different characteristic peaks along with (311) predominant orientation corresponding to orthorhombic crystal structure with Pnma space group. Electric and dielectric properties were studied over a frequency range of 1 Hz–1 MHz at different temperatures. The conductivity was found to be increased with increasing temperature following Arrhenius relation with an estimated activation energy of 0.44 eV. The dielectric properties were analyzed in the framework of complex dielectric permittivity and complex electric modulus formalisms. The complex permittivity as a function of frequency and temperature was investigated. Several important parameters, such as activation energy, ionic hopping frequency, carrier concentration, ionic mobility, and diffusion coefficient, etc., were determined. The electrochemical characteristics of LiFePO4 are examined in aqueous region. It exhibited a good reversible cyclic voltammogram on sweeping the potential upward and downward with discharge capacity of 140 mAh/g. 相似文献