- Effect of alkyl groups in organic part of polyoxo-metalates based ionic liquids on properties of flame retardant polypropylene
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The structure-property relationship of a series of polyoxo-metalates based ionic liquids (PILs) modified polypropylene (PP)/Intumescent flame retardant (IFR) composites were studied. The results showed that the chemical structure of PILs has a great effect on properties of PP composites. The flame retardancy of PP/IFR/PILs composites with a shorter alkyl group are better than that with a longer alkyl group. The PP/IFR/PIL composite with 0.5 wt% PIL with 1-butyl-3-methyl imidazole and 14.5% IFR gets the UL-94 V-0, but achieving the same UL-94 grade needs no less than 19.5 wt% IFR and 0.5 wt% PIL with 1-octyl-3-methyl imidazole. In addition, PILs modified by different groups have great effects on the mechanical properties, the PP/IFR/PIL composites containing 1-dodecyl-3-methyl imidazole obtain the best notch impact strength. The results show that the flame retardant and mechanical properties of PP/IFR/PILs composites can be tailored by changing the cation structure of PIL.
- Chen, Shengjiao,Wang, Chengle,Li, Juan
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- Investigation of the role of ionic liquids in tuning the pK a values of some anionic indicators
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The effect of imidazolium-based ionic liquids, ([C12mim][Cl] and [C8mim][Cl]), on the acid-base equilibria of two sulfonated indicators has been studied. The presence of ILs leads to decreased pK a values because of the st
- Safavi,Abdollahi,Maleki,Zeinali
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- Deep desulfurization of light oil through extraction and oxidation processes using H2O2/tungstophosphoric acid in room-temperature ionic liquids
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In this research, using room-temperature ionic liquids (RTILs) as the solvents to combine solvent extraction and chemical oxidation processes in one-pot operation for the desulfurization of fuel oil was pursued. In this solvent extraction and chemical oxidation desulfurization (SECOD), RTILs as media are immiscible with oil; sulfur compounds in oil are extracted into RTILs and oxidized thereafter to the corresponding sulfones by H2O 2/TPA (tungstophosphoric acid). During SECOD, these high polar sulfones partition mainly in the ionic liquid phase. Hence, it results in their continuous removal from oil, which leads to deep desulfurization. To study the SECOD, we employed dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) in hexadecane asmodel oil systems and compared the effects of RTILs on the removal of DBT and 4,6-DMDBT. The desulfurization rates followed the order OMIM+PF6 - > BMIM+PF6 - > BMIM+BF4 -. Both OMIM+PF6 - and BMIM+PF6 - are water-immiscible and form three-phase (oil-water- ionic liquid) reaction systems; these three-phase systems offer higher removal efficiencies of sulfur compounds from oil. Under the optimized conditions, SECOD process reduced the sulfur content of diesel light oil from 897 to 42 ppm (i.e., 95% desulfurization efficiency) in a one-batch operation.
- Chuang, Li-Lin,Huang, Jung-Fu,Lo, Wen-Hen,Wei, Guor-Tzo
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- Modulating the Aggregation Behavior of 1-Methyl-3-Octylimidazolium Chloride by Alcohols in Aqueous Media
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The self-organization and aggregation behavior of a surface active ionic liquid (SAIL) 1-methyl-3-octylimidazolium chloride [C8mim]Cl, was investigated in aqueous solutions of alcohols 1,2-propanediol and 1-propanol in different compositions using conductivity, surface tension and fluorescence measurements at room temperature. This surface active ionic liquid was synthesized by the reaction of 1-methylimidazole with 1-chlorooctane. Fluorescence spectroscopy was employed to get detailed insight into the local microenvironment of the aggregates, critical aggregation concentrations (CAC) and aggregation number (Nagg.). Degree of ionization (α), CAC and various thermodynamic parameters like the standard Gibbs free energy of aggregation (ΔGagg. 0), standard enthalpy of aggregation (ΔHagg. 0) and standard entropy of aggregation (ΔSagg. 0) were calculated using conductivity measurements at different temperatures (288.15, 298.15 and 308.15?K). The surface activity of the IL in various mixed solvents was evaluated from surface tension measurements by calculating various surface parameters like the minimum surface area occupied by a single ionic liquid molecule (Amin), adsorption efficiency (pC20), maximum excess concentration at the surface (Γmax), effectiveness of surface tension reduction(ΠCAC), surface tension at CAC (γCAC), p (packing parameter) and CAC at different compositions. Increases in the CAC values were observed with the increase in the amount of alcohols which is attributed to the balancing between electrostatic and hydrophobic interactions. The results from different techniques show that the CAC increases with increase in the amount of the alcohol which is due to the solubilization of the IL molecules which delays the aggregation process. This shows that the spontaneity of the aggregation process of IL decreases with the increase in the concentration of alcohols in water.
- Pal, Amalendu,Yadav, Alka
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- Ionic liquids/water distribution ratios of some polycyclic aromatic hydrocarbons
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By using the shake-flask procedure, the distribution ratios (D) at infinite dilution and 298.1 K of 15 polycyclic aromatic hydrocarbons (PAHs) between room-temperature ionic liquids, l-alkyl-3-methylimiazolium hexafluorophosphates ([CnMIM] [PF
- Liu, Jing-Fu,Chi, Yu-Guang,Peng, Jin-Feng,Jiang, Gui-Bin,Joensson, Jan Ake
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- Buffered chlorogallate(iii) ionic liquids and electrodeposition of gallium films
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Buffering of Lewis acidic chlorometallate ionic liquids is a useful tool to modify their properties for electrochemical and catalytic applications. Lewis acidic chlorogallate(iii) ionic liquids containing the 1-octyl-3- methylimidazolium cation, buffered with sodium chloride, were studied using 71Ga NMR spectroscopy and cyclic voltammetry. All the studied Lewis acidic compositions (0.50 GaCl3 ≤ 0.75) could be buffered to mild or moderate acidity, but not to neutrality. Electrodeposition of gallium from such buffered systems was possible, yielding deposits of improved morphology over the unbuffered ionic liquids, due to the constant melt composition maintained by the buffer. These findings were in a stark contrast with older studies on chloroaluminate(iii) ionic liquids buffered with sodium chloride.
- Seddon, Kenneth R.,Srinivasan, Geetha,Swad?ba-Kwa?ny, Ma?gorzata,Wilson, Anthony R.
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- The Influence of Water and Metal Salt on the Transport and Structural Properties of 1-Octyl-3-methylimidazolium Chloride
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The addition of diluents to ionic liquids (ILs) has recently been shown to enhance the transport properties of ILs. In the context of electrolyte design, this enhancement allows the realisation of IL-based electrolytes for metal-air batteries and other storage devices. It is likely that diluent addition not only impacts the viscosity of the IL, but also the ion-ion interactions and structure. Here, we investigate the nano-structured 1-methyl-3-octylimidazolium chloride (OMImCl) with varying water concentrations in the presence of two metal salts, zinc chloride and magnesium chloride. We find that the choice of metal salt has a significant impact on the structure and transport properties of the system; this is explained by the water structuring and destructing properties of the metal salt.
- Goujon, Nicolas,Byrne, Nolene,Walsh, Tiffany R.,Forsyth, Maria
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- Opportunities for ionic liquids in recovery of biofuels
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Room temperature ionic liquids have potential as extractants in recovery of butyl alcohol from fermentation broth; water solubility in ionic liquid and ionic liquid solubility in water are important factors affecting selectivity of butyl alcohol extractio
- Fadeev,Meagher
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- Ultrafast igniting, imidazolium based hypergolic ionic liquids with enhanced hydrophobicity
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Exploring ultrafast igniting and hydrolytically stable ionic liquids (ILs) has a wide scope in hypergolic rocket fuels. The hydrophobicities of ILs, induced by a smart change in alkyl substituents of imidazolium cations with energy-rich cyanoborohydride, [BH3CN]- and dicyanamide, [DCA]- anions were examined for the first time. The physico-chemical properties and performance of ILs were also studied. Consequently, hydrolytic stability in terms of moisture study of all the ILs was thoroughly investigated under standard environmental conditions. The analysis indicates that the IL 14, 1-allyl-3-octyl imidazolium cyanoborohydride is most hydrophobic and hydrolytically stable. Studies evaluating the role of the cationic hydrocarbon chain and the nature of anions of ILs on the properties of hypergolic fuel were carried out. All the ILs are liquid at room temperature and exhibit a positive heat of formation. IL 10, 1,3-diallyl-imidazolium cyanoborohydride exhibited the shortest ignition delay of 1.9 ms with WFNA and IL 11, 1-allyl-3-ethyl imidazolium cyanoborohydride presented the lowest viscosity of 16.62 mPa s. Therefore, these ILs can be suggested as potential candidates for replacing acutely toxic and carcinogenic hydrazine and its methylated derivatives as hypergolic fuels.
- Bhosale, Vikas K.,Kulkarni, Prashant S.
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- Impact of imidazolium-based ionic liquids on the structure and stability of lysozyme
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Various types of water-miscible aprotic ionic liquids (ILs) with different cations (1-ethyl-3-methylimidazolium, 1-butyl-3-methylimidazolium, 1-octyl-3-methylimidazolium) and anions (ethylsulfate and chloride) were used as co-solvents to investigate the s
- Satish, Lakkoji,Rana, Shubhasmin,Arakha, Manoranjan,Rout, Lipeeka,Ekka, Basanti,Jha, Suman,Dash, Priyabrat,Sahoo, Harekrushna
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- Activation of hydrogen peroxide by the nitrate anion in micellar media
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We present the activation of hydrogen peroxide by micellar imidazolium nitratesviaH-bond formation in water, as shown by vibrational spectroscopy and supported by DFT calculations. Mechanistic insight into the interactions of the surfactant cation, the nitrate anion and H2O2is given. The micelles solubilise and epoxidise cyclooctene in the aqueous phase.
- Schmidt, Fabian,Zehner, Bastian,Kaposi, Marlene,Drees, Markus,Mink, János,Korth, Wolfgang,Jess, Andreas,Cokoja, Mirza
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supporting information
p. 1965 - 1971
(2021/03/26)
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- The one-pot synthesis of butyl-1H-indol-3-alkylcarboxylic acid derivatives in ionic liquid as potent dual-acting agent for management of BPH
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Based on the SAR of both α1-AR antagonists and 5α-reductase (5AR) inhibitors, the dual-acting agent 4-(1-(4-(4-(2-methoxyphenyl)piperazin-1-yl)butyl)-1H-indol-3-yl)butanoic acid 4aaa was designed against BPH and synthesized by two steps of N-alkylation. One-pot protocol towards 4aaa was newly developed. With IL [C6min]Br as solvent, the yield of 4aaa was increased to 75.1% from 16.0% and the reaction time was shortened in 1.5 h from 48 h. 25 derivatives structurally based on arylpiperazine and indolyl butyric acid with alkyl linker were prepared. The protocol was futher extended to get another 14 derivatives wherein O-alkylation was involved, and applied to the synthesis of biologically efficient molecules DPQ and Aripiprazole. Expectedly, compound 4aaa exhibited dual inhibition of α1-AR and 5α-reductase, and exhibited no obvious cytotoxicity against human cells. The pharmacokinetic properties of 4aaa was also determined.
- Chen, Kaixuan,Jiang, Zhenzhou,Liu, Shuwen,Xi, Baomin,Yang, Fubiao,Zeng, Li-Yan,Zeng, Yunong
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- Ionic liquid-assisted synthesis of Pt nano thin films at toluene–water interface: Enhanced CO tolerance in methanol fuel cells and adsorptive removal of p-nitrophenol from water
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In this investigation, we report a one-pot method for the synthesis of Pt/ionic liquid nano thin films at organic-aqueous media at room temperature without using any harsh conditions. Synthesized Pt/ionic liquid thin films were characterized with common analytical techniques. Transmission electron microscope images confirmed the formation of spherical particles having a size distribution in the range of 4–12 nm. Ionic liquids have a key role in the control of better size distribution and prevent from agglomeration of nanostructures by preparing a shell around particles. These catalysts were applied for the reduction of toxic p-nitrophenol into non-toxic p-aminophenol and exhibited good catalytic activity. Also, they exhibit excellent CO tolerance in methanol oxidation process of fuel cells. This method provides a novel, rapid, low cost and economical alternative for the reduction of toxic organic pollutants in water and also to prepare high quality catalysts with low metal loading for methanol fuel cells. Pt/1-aminoethyl-3-methylimidazolium bromide exhibits better CO tolerance than Pt/1-methyl-3-octylimidazolium chloride and Pt/1-methyl-3-octylimidazolium tetrafluoroborate thin films.
- Sharfand, Saba Hamzepour,Hoseini, S. Jafar,Bahrami, Mehrangiz
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p. 483 - 497
(2018/06/26)
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- Synthetic method of dexmedetomidine hydrochloride intermediate
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The invention discloses a synthetic method of a dexmedetomidine hydrochloride intermediate. The synthetic method comprises the following step: carrying out contact reaction on 1-(1-haloethyl)-2,3-dimethylbenzene and imidazole in ionic liquid in the presence of alkali and [1,1'-bis(diphenylphosphino) ferrocene] palladium dichloride to obtain the dexmedetomidine hydrochloride intermediate 4-[1-(2,3-dimethyl phenyl) ethyl]-1H-imidazole. The method is short in reaction time and high in yield, and has good selectivity for a target (S)-isomer.
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Paragraph 0030
(2017/08/28)
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- Method for preparing dexmedetomidine hydrochloride for anesthesia and sedation during operation
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The invention discloses a method for preparing dexmedetomidine hydrochloride for anesthesia and sedation during an operation. The method comprises the following steps: (a) stirring and reacting 2,3-dimethyl styrene and imidazole in ionic liquid to obtain 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole in the presence of an iron salt; (b) reacting the 4-[1-(2,3-dimethylphenyl)ethyl]-1H-imidazole with L-(+)-tartaric acid, and performing suction filtering to obtain dexmedetomidine tartrate; (c) stirring the dexmedetomidine tartrate in an aqueous solution of sodium hydroxide, performing dichloromethane extraction and concentration, and stirring in a saturated hydrochloric acid methanol solution to obtain the dexmedetomidine hydrochloride. According to the method, the ionic liquid is used for alkylation reaction of the imidazole under catalysis of the iron salt, so that the reaction time is effectively shortened, and high yield is achieved; fewer steps are required, and the cost is lower; conditions in each step are mild, use of a large amount of lewis acid is avoided, and easiness for industrial production is achieved.
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Paragraph 0028
(2017/07/05)
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- Preparation process of dexmedetomidine hydrochloride for ICU (intensive care unit) sedation and analgesia
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The invention discloses a preparation process of dexmedetomidine hydrochloride for ICU (intensive care unit) sedation and analgesia. The preparation process includes the steps: first, stirring and reacting 1-(1-halogenated ethyl)-2, 3-dimethyl benzene and imidazole in ionic liquid under catalysis of ferric trichloride to obtain 4-[1-(2, 3-dimethyl phenyl) ethyl]-1H-imidazole; second, refluxing the 4-[1-(2, 3-dimethyl phenyl) ethyl]-1H-imidazole obtained in the first step and L-(+)-tartaric acid in absolute ethyl alcohol, and performing standing, cooling and suction filtration to obtain dexmedetomidine tartrate; third, stirring the dexmedetomidine tartrate in sodium hydroxide aqueous solution, extracting methylene dichloride, concentrating the solution, stirring the solution in saturated hydrochloric acid methanol solution to obtain the dexmedetomidine hydrochloride. The method is short in reaction time, high in yield, milder in condition and suitable for industrial popularization.
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Paragraph 0030
(2017/08/28)
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- Anion Analysis of Ionic Liquids and Ionic Liquid Purity Assessment by Ion Chromatography
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The simultaneous determination of halide impurities (fluoride, chloride, bromide, and iodide) and ionic liquid (IL) anions (tetrafluoroborate, hexafluorophosphate, and triflimide) using ion chromatography was developed with a basic, non-gradient ion chromatography system. The non-gradient method uses the eluent Na2CO3/NaHCO3in water/acetonitrile (70:30 v:v) on the AS 22 column to enable a rapid and simultaneous analysis of different IL and halide anions within an acceptable run-time (22 min) and with good resolution R of larger than 2.4, a capacity k′ between 0.4 and 5.1, selectivities α between 1.3 and 2.1, and peak asymmetries Asof less than 1.5. Halide impurities below 1 ppm (1 mg·L–1of prepared sample solution) could be quantified. A range of ionic liquids with tetrafluoroborate [BF4]–, hexafluorophosphate [PF6]–, and bis(trifluoromethylsulfonyl)imide (triflimide) [NTf2]–anions combined with cations based on imidazole, pyridine, and tetrahydrothiophene could be analyzed for their anion purity. The IL-cations do not influence the chromatographic results. With the analysis of 18 ILs differing in their cation-anion combination we could prove the general applicability of the described method for the anion purity analysis of ionic liquids with respect to halide ions. The IL-anion purity of most ILs was above 98 wt %. The highest IL-anion purity was 99.8 wt %, implying anion impurities of only 0.2 wt %. The used halide anion from the synthesis route was the major anion impurity, yet with chloride also bromide and fluoride (potentially from hydrolysis of [BF4]–) were often detected. When iodide was used, at least chloride but sometimes also bromide and fluoride was present. However, even if the IL-anion content is above 99 wt %, it does not necessarily indicate an ionic liquid devoid of other impurities. From the IC analysis, one can also deduce a possible cation impurity if one takes into account the expected (calculated) IL-anion content. A matching experimental and theoretical IL-anion content excludes, a higher experimental content indicates the presence of residual KBF4, NH4PF6, or LiNTf2salt from the halide to IL-anion exchange.
- Rutz, Christina,Schmolke, Laura,Gvilava, Vasily,Janiak, Christoph
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supporting information
p. 130 - 135
(2017/02/05)
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- Densities and viscosities of binary mixtures of magnetic ionic liquids 1-alkyl-3-methylimidazolium tetrachloroferrate with ethyl acetate at temperatures (293.15 to 323.15) K
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The physicochemical properties of the binary mixtures of magnetic ionic liquids (MILs) are essential for industrial process designs of their applications. In this work, three MILs were synthesized and characterized, including 1-butyl-3-methylimidazolium tetrachloroferrate ([Bmim][FeCl4]), 1-hexyl-3-methylimidazolium tetrachloroferrate ([Hmim][FeCl4]) and 1-octyl-3-methylimidazolium tetrachloroferrate ([Omim][FeCl4]). Densities and viscosities of binary mixtures of these MILs with ethyl acetate (EA) were determined over the whole range of compositions at temperatures (293.15 to 323.15) K at 5 K intervals. The data of densities as a function of temperature were fitted with linear equation and viscosities were correlated with Vogel–Fucher–Tammann (VFT) equation. Results showed that the densities and viscosities of the binary mixtures decreased significantly with the IL concentration decreasing and with temperature increasing. Excess molar volumes (VE) and viscosity deviations (Δη) were calculated and fitted well with the Redlich-Kister equation. The negative VE and Δη over the entire composition range indicated that there were stronger interactions between MILs and EA than those among MILs and among EA.
- Li, Xiaohua,Zhou, Qing,Lu, Xingmei,Zhang, Suojiang
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p. 285 - 292
(2017/08/21)
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- Synthesis and characterization of eight hydrophilic imidazolium-based ionic liquids and their application on enhanced oil recovery
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In order to difficulties in producing large amount of crude oil and remaining oil by primary and secondary oil recovery processes, enhanced oil recovery (EOR) techniques have been developed. Water injection is one of the EOR methods which has shown great potential in recent years. The water flooding process is more effective when the injected water is enriched by chemicals which improve the oil recovery by reducing interfacial tension (IFT) and alternating wettability. In this work eight long alkyl chain imidazolium based ionic liquids (ILs) including Octyl, Decyl, Dodecyl and Tetradecyl methylimidazolium and two different anions namely Chlorid and trihydrogen diphosphate (THDP), were synthesized and characterized by 1HNMR and elemental analysis. As a nobility it should be noted that ILs containing THDP anion have not been synthesized yet and they were used in upstream oil industry for the first time. Furthermore, some physicochemical properties were investigated for studied ILs as a function of temperature. The synthesized ILs were examined as additives in injected water to reduce the IFT in water flooding process. The critical micelle concentration (CMC) point and IFT of enriched sea water by ILs/crude oil, were measured as a function of ILs concentration. The results showed that ILs can be good candidates for EOR technology due to their significant behavior in IFT reduction and their low consumption. The consumed concentrations for ILs were observed at ppm levels, so they are favorable choices when economic concerns are considered. According to obtained results, as the alkyl chain was longer, the CMC point and IFT values were lower. Moreover the investigation of IFT values, revealed that ILs containing THDP anion were more efficient in IFT reduction compared with ILs including chloride anion. [C14mim][Cl] and [C14mim][THDP] were the most effective ILs which 50 and 25 ppm of these ILs, reduced the IFT values to 0.65 ± 0.04 and 0.5 ± 0.02, respectively.
- Yousefi,Naseri,Abdouss,Miran Beigi
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p. 370 - 377
(2017/10/30)
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- Thermodynamic evaluation of imidazolium based ionic liquids with thiocyanate anion as effective solvent to thiophene extraction
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In order to have deep insight on the molecular interactions between thiophene (TS) and ionic liquids, the density, speed of sound and refractive index of binary liquid mixture of TS with 1-hexyl-3-methylimidazolium thiocyanate [HMIM][SCN], and 1-octyl-3-m
- Shekaari, Hemayat,Zafarani-Moattar, Mohammed Taghi,Niknam, Mehrdad
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p. 975 - 984
(2016/05/09)
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- Facile aromatic nucleophilic substitution (SNAr) reactions in ionic liquids: An electrophile-nucleophile dual activation by [Omim]Br for the reaction
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A facile aromatic nucleophilic substitution (SNAr) reaction in recyclable [Omim]Br under relatively mild conditions has been described. An electrophile-nucleophile dual activation by [Omim]Br is also discovered based on control experiments, 1H NMR and IR spectroscopies. This chemistry provides an efficient and metal-free approach for the generation of Caryl-X (XS, N, O) bonds, many of which are significant synthetic intermediates or drugs, making this methodology attractive to both synthetic and medicinal chemistry.
- Zhang, Xiao,Lu, Guo-Ping,Cai, Chun
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supporting information
p. 5580 - 5585
(2016/10/21)
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- Novel ionic liquid with peroxyniobate-radical negative ions and preparing method thereof
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The invention relates to novel ionic liquid with peroxyniobate-radical negative ions and a preparing method thereof. The ionic liquid comprises imidazolium salt positive ions, quaternary ammonium salt positive ions and the peroxyniobate-radical negative ions. The preparing method of the ionic liquid includes the steps that 1, alkyl-replacing N-methylimidazole hydrochloride is prepared from N-methylimidazole; 2, alkyllimidazolium salt chloride and quaternary ammonium salt halogenide are subjected to ion exchange to obtain corresponding ethanol solutions of hydroxide; 3, ammonium peroxyniobate is prepared from commercial niobium pentoxide with the document method; 4, the brand-new-structure ionic liquid with the peroxyniobate-radical negative ions is obtained with the ion exchange (acid-base neutralization) method. According to the novel ionic liquid with the peroxyniobate-radical negative ions and the preparing method thereof, the ionic liquid is prepared for the first time, the preparing method is simple, the yield is high, and the characteristics of a niobium element can be fully used to carry out a certain catalytic oxidation reaction.
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Page/Page column 6
(2016/12/01)
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- Properties and catalytic activity of magnetic and acidic ionic liquids: Experimental and molecular simulation
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The exploitation of dual functional magnetic and acidic ionic liquids (MAILs) for hydrolysis of cellulose to platform chemicals can solve some practical challenges through easy separation of products and efficient catalyst recyclability. In this work, seven Cnmim/FeCl4 MAILs were synthesized and investigated with combined experimental and molecular dynamics. The MAILs contained FeCl4- anions and exhibited a typical hard magnetic materials behavior with rather strong magnetic susceptibilities. These MAILs were stable up to 250-310 C, the decomposition was started up at 250/310-480-810 C in two steps with the formation of the undecomposed residue. The Gibbs energy for the reaction of glucose/xylose conversion to 5-hydroxymethylfurfural by metal chlorides in the CnmimCl ionic liquid was studied using the density functional theory calculations and the results that C3mim/WCl3 may be the most hopeful catalyst. The MAILs have the potential to open up promising new catalytic systems because of their easy product separation and efficient catalyst recyclability.
- Zhou, Cunshan,Yu, Xiaojie,Ma, Haile,Huang, Xingyi,Zhang, Henan,Jin, Jian
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p. 300 - 307
(2014/03/21)
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- Enhanced antimicrobial activities of 1-alkyl-3-methyl imidazolium ionic liquids based on silver or copper containing anions
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We have developed a series of 1-alkyl-3-methylimidazolium tetrachlorocuprate(ii) and dibromoargentate(i) ionic liquids with enhanced antimicrobial activity when compared with 1-alkyl-3-methylimidazolium chloride ionic liquids. These new ionic liquids proved to be effective against a range of pathogenic bacteria and fungi.
- Gilmore, Brendan F.,Andrews, Gavin P.,Borberly, Gabor,Earle, Martyn J.,Gilea, Manuela A.,Gorman, Sean P.,Lowry, Andrew F.,McLaughlin, Martin,Seddon, Kenneth R.
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supporting information
p. 873 - 876
(2013/07/11)
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- Densities, excess molar and partial molar volumes for water + 1-butyl- or, 1-hexyl- or, 1-octyl-3-methylimidazolium halide room temperature ionic liquids at T = (298.15 and 308.15) K
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Experimental densities for seven mixtures of water + 1-butyl-3- methylimidazolium iodide, [C4mim][I], + 1-hexyl-3-methylimidazolium chloride, [C6mim][Cl], + 1-hexyl-3-methylimidazolium bromide, [C 6mim][Br], + 1-hexyl-3-me
- Sastry, Nandhibatla V.,Vaghela, Nilesh M.,Macwan, Pradip M.
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- Does alkyl chain length really matter? Structure-property relationships in thermochemistry of ionic liquids
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DSC was used for determination of reaction enthalpies of synthesis of ionic liquids [Cnmim][Cl]. A combination of DSC with quantum chemical calculations presents an indirect way to study thermodynamics of ionic liquids. The indirect procedure for vaporization enthalpy was validated with the direct experimental measurements by using thermogravimetry. First-principles calculations of the enthalpy of formation in the gaseous phase have been performed for the ionic species using the CBS-QB3 and G3 (MP2) theory. Experimental DSC data for homologous series of alkyl substituted imidazolium, pyridinium, and pyrrolidinium based ionic liquids with anions [Cl] and [Br] were collected from the literature. We have shown that enthalpies of formation, enthalpies of vaporization, and lattice potential energies are linearly dependant on the alkyl chain length. The thermochemical properties of ILs generally obey the group additivity rules and the values of the additivity parameters for enthalpies of formation and vaporization seem to be very close to those for molecular compounds.
- Verevkin, Sergey P.,Zaitsau, Dzmitry H.,Emel'Yanenko, Vladimir N.,Ralys, Ricardas V.,Yermalayeu, Andrei V.,Schick, Christoph
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- Acidity and basicity of halometallate-based ionic liquids from X-ray photoelectron spectroscopy
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X-ray photoelectron spectroscopy (XPS) has been used to investigate a series of 1-octyl-3-methylimidazolium halometallate ionic liquids of the general formula (1 - χ)[C8C1Im]Cl-χMCly (where χ is the mole fraction of metal halide and y = 2 or 3). The ionic liquids emitted good photoelectron fluxes allowing the measurement of high quality spectra with good peak resolution. Interrogation of the XPS data has allowed the prediction of trends in solvent parameters for these ionic liquids, including hydrogen bond basicity and Lewis acidity. Clear changes to the shape and energy of metal originated photoelectron peaks, as a function of mole fraction of metal halide, aids the identification of complex polynuclear anions within the ionic liquids.
- Taylor, Alasdair W.,Men, Shuang,Clarke, Coby J.,Licence, Peter
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p. 9436 - 9445
(2013/07/27)
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- Synthesis, characterization and thermal properties of thiosalicylate ionic liquids
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In an attempt to produce new functionalized ionic liquids, a series of thiosalicylate ionic liquids based on imidazolium, ammonium, phosphonium, choline and pyrrolidinium cations were synthesized. The compounds were characterized by Infra Red (IR), Nuclear Magnetic Resonance (NMR) and mass spectra (ESI-MS). Their glass-transition temperatures, melting points and decomposition temperatures have been measured. Physicochemical properties of ionic liquids are influenced by alkyl chain length and nature of the cation of ionic liquids. Indian Academy of Sciences.
- Wilfred, Cecilia Devi,Mustafa, Fadwa Babiker
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p. 1511 - 1515
(2014/04/03)
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- Solubility of CO2, H2S, and their mixture in the ionic liquid 1-octyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide
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Gaseous solubilities of carbon dioxide (1), hydrogen sulfide (2), and their binary mixture (x2 ≈ 0.2, 0.5, 0.8) have been measured in the ionic liquid 1-octyl-3-methylimidazolium bis(trifluoromethyl)sulfonylimide ([C8mim][Tf2N]) at temperatures ranging from (303.15 to 353.15) K and at pressures under 2 MPa. The observed PTx solubility data were used to obtain Henry's law constants and correlated by three models: (1) the simple Krichevsky-Kasarnovsky (KK) equation, (2) a model comprised of the extended Henry's law and the Pitzer's virial expansion for the excess Gibbs free energy, and (3) the generic Redlich-Kwong (RK) cubic equation of state proposed for gas-ionic liquid systems. The correlations from the three models show quite good consistency with the experimental data for IL/CO2 and IL/H 2S binary mixtures within experimental uncertainties. For IL/CO 2/H2S ternary mixtures, the RK model shows the best correlation with the experimental data. The comparison showed that the solubility of H2S is about two times as great as that of CO 2 in the ionic liquid studied in this work. It was further found, by comparison of the experimental data of this study with those of previous reports, that the solubility of H2S in [Cnmim][Tf 2N] ILs increases as the number of carbon atoms in the alkyl substituent of methylimidazolium cation, n, increases. In addition, quantum chemical calculations at DFT/B3LYP level of theory using 6-311+G(d) and 6-311++G(2d,2p) basis sets were performed on the isolated systems studied in this work to provide explanations from a molecular point of view for the observed experimental trends.
- Jalili, Amir Hossein,Safavi, Mohammadali,Ghotbi, Cyrus,Mehdizadeh, Ali,Hosseini-Jenab, Masih,Taghikhani, Vahid
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experimental part
p. 2758 - 2774
(2012/05/20)
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- Parallel microwave-assisted synthesis of ionic liquids and screening for denitrogenation of straight-run diesel feed by liquid-liquid extraction
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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
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experimental part
p. 427 - 432
(2012/07/01)
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- Sonochemical synthesis of 0D, 1D, and 2D zinc oxide nanostructures in ionic liquids and their photocatalytic activity
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Ultrasound synthesis of zinc oxide from zinc acetate and sodium hydroxide in ionic liquids (ILs) is a fast, facile, and effective, yet highly morphology- and size-selective route to zinc oxide nanostructures of various dimensionalities. No additional organic solvents, water, surfactants, or templating agents are required. Depending on the synthetic conditions, the selective manufacturing of 0D, 1D, and 2D ZnO nanostructures is possible: Whereas the formation of rodlike structures is typically favored, ZnO nanoparticles can be obtained either under strongly basic conditions or by use of ILs with a long alkyl chain, such as 1-n-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cnmim][Tf2N]; n>8). A short ultrasound irradiation time favors the formation of ZnO nanosheets. Prolonged irradiation leads to the conversion of the ZnO nanosheets into nanorods. In contrast, ionothermal synthesis (conventional heating) does not allow for morphology tuning by variation of the IL or other synthesis conditions, as the longer reaction times required lead always to the formation of well-developed hexagonal nanocrystals with prismatic tips. The ZnO nanostructures synthesized by using ultrasound were efficient photocatalysts in the photodegradation of methyl orange. The photoactivity was observed to be as high as 95 % for ZnO nanoparticles obtained in [C10mim][Tf 2N].
- Alammar, Tarek,Mudring, Anja-Verena
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experimental part
p. 1796 - 1804
(2012/04/04)
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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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scheme or table
p. 1352 - 1356
(2010/04/02)
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- Speciation of chloroindate(iii) ionic liquids
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A range of chloroindate(iii) ionic liquid systems was prepared by mixing of 1-alkyl-3-methylimidazolium chloride with indium(iii) chloride in various ratios, expressed as the mol fraction of indium(iii) chloride, χInCl3. For χInCl3 ≤ 0.50, the products were liquids, whereas for χInCl3 > 0.50, the products were biphasic (suspensions of a solid in an ionic liquid). Speciation of these chloroindate(iii) systems was carried out using a wide range of techniques: differential scanning calorimetry (DSC), polarised optical microscopy (POM), liquid-state and solid-state 115In NMR spectroscopy, X-ray photoelectron spectroscopy (XPS) and extended X-ray absorption fine structure (EXAFS). Ionic liquids prepared using an excess of the organic chloride (χInCl3 6]3-, [InCl5]2- and [InCl4]- anions, in proportions dependent on the χInCl3 value. Equimolar mixtures yielded single compounds: 1-alkyl-3-methylimidazolium tetrachloroindates(iii). Systems containing an excess of indium(iii) chloride (χInCl3 > 0.5) contained indium(iii) chloride powder suspended in a neutral tetrachloroindate ionic liquid.
- Apperley, David C.,Hardacre, Christopher,Licence, Peter,Murphy, Richard W.,Plechkova, Natalia V.,Seddon, Kenneth R.,Srinivasan, Geetha,Swadzba-Kwasny, Malgorzata,Villar-Garcia, Ignacio J.
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experimental part
p. 8679 - 8687
(2011/01/05)
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- Microwave synthesis and properties of a series of N-alkyl-N-methylimidazolium chloride ionic liquids
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Seven N-alkyl-N-methylimidazolium chloride ionic liquids were synthesized under the organic-solvent-free condition with microwave irradiation. The structures were characterized and confirmed by 1H NMR and melting points were determined by differential scanning calorimetry (DSC). Their surface tensions and water adsorption properties were measured at room temperature. The results showed that there was a decrease in surface tension and water adsorption with an increasing substituting alkyl chain length in the 1-position of N of the cation. However the melting points increased with an increasing substituting alkyl chain length of the N of the cation.
- Pan,Wang,Pei
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experimental part
p. 6026 - 6030
(2010/12/19)
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- Influence of imidazolium bis(trifluoromethylsulfonylimide)s on the rotation of spin probes comprising ionic and hydrogen bonding groups
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The influence of the alkyl chain length in 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonylimide)s is studied to explore the rotation of piperidine-1-yloxyl derivatives substituted with either hydrogen bonding hydroxy group or ionic substituents, such as the cationic trimethylammonium or the anionic sulfate group placed at the 4 position. Structural variation of the ionic liquids results in differences of their viscosity influencing the rotation of the spin probes. The size of the average rotational correlation times of the spin probes dissolved in the ionic liquids depends further on the additional substituent in 4-position at these spin probes. The rotational correlation time exhibits a linear dependence on the ionic liquid viscosity in the case of the spin probe forming hydrogen bonding with the ionic liquids. In contrast to this, a deviation from the Stokes-Einstein behavior is found in the case of rotation of the charged spin probes in the 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonylimide)s substituted with a longer alkyl chain. This effect may be explained by phase separation on a molecular level between the charged part of the ionic liquid and the longer alkyl chains bound at the imidazolium ion. Although the neutral and the cationic spin probes show only a slight dependence between ionic liquid structure variation and the hyperfine coupling constants, structural effects cause changes in the hyperfine coupling constants in the case of the anionic spin probes. These probes strongly interact with the imidazolium ion.
- Strehmel, Veronika,Rexhausen, Hans,Strauch, Peter
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experimental part
p. 1933 - 1940
(2010/09/05)
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- Effects of alkyl chain length on properties of 1-alkyl-3-methylimidazolium fluorohydrogenate ionic liquid crystals
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A series of 1-alkyl-3-methylimidazolium fluorohydrogenate salts (C xMIm(FH)2F, x=8, 10, 12, 14, 16, and 18) have been characterized by thermal analysis, polarized optical microscopy, IR spectroscopy, X-ray diffraction, and anisotropic ionic conductivity measurements. Liquid crystalline mesophases with a smectic A interdigitated bilayer structure are observed from C10 to C18, showing a fan-like or focal conic texture. The temperature range of the mesophase increases with the increase in the alkyl chain length (from 10.1°C for C10MIm(FH)2F to 123.1°C for C18MIm(FH) 2F). The distance between the two layers in the smectic structure gradually increases with increasing alkyl chain length and decreases with increasing temperature. Conductivity parallel to the smectic layers is around 10mS-cm?1 regardless of the alkyl chain length, whereas that perpendicular to the smectic layers decreases with increasing alkyl chain length because of the thicker insulating sheet with the longer alkyl chain.
- Xu, Fei,Matsumoto, Kazuhiko,Hagiwara, Rika
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body text
p. 12970 - 12976
(2011/02/23)
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- The conductivity of imidazolium-based ionic liquids from (-35 to 195) °c. A. variation of cations alkyl chain
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Data for the conductivity (κ) of the ionic liquids [emim][BF 4], [bmim][BF4], [hmim][BF4], and [omim][BF4] from (-35 to 195) °C are reported. The data can be well-fit with the Vogel-Fulcher-Tammann equation. Additionally, molar conductivities (Λ) were determined for the limited temperature range of (5 to 65) °C. Walden plots of these data indicate that the investigated compounds can be classified as "high-ionicity" ionic liquids. It is suspected that the large difference between the present κ values and some of the literature values is mainly due to the neglect of BF4-hydrolysis.
- Stoppa, Alexander,Zech, Oliver,Kunz, Werner,Buchner, Richard
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experimental part
p. 1768 - 1773
(2011/07/30)
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- IONIC ADDITIVE FOR CATALYSIS IN BIPHASIC REACTION SYSTEMS
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An additive for improving the rate of catalysis in biphasic reaction systems is disclosed. The additive is an ionic molecule comprising an organic cation such as a heterocyclic compound or a quaternary ammonium or phosphonium cation, and an anion which may be organic or inorganic. A process for improved catalysis in an aqueous biphasic system wherein the catalyst is substantially dissolved in the aqueous phase and the substrate is substantially contained in the non-aqueous phase is also described. A suitable additive is 1-octyl-3-methylimidazolium halide. Examples of suitable catalytic reactions include the hydrogenation, hydrosilation, hydroboration, hydrovinylation, hydroformylation, oxidation and hydroxycarbonylation of alkenes, and Heck, Suzuki, Stille, and Sonigashira coupling.
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Page/Page column 2
(2009/12/28)
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- Aqueous-biphasic hydroformylation of alkenes promoted by "weak" surfactants
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The aqueous-biphasic hydroformylation of higher alkenes catalyzed by Rh/TPPTS has been carried out in the presence of imidazolium, pyridinium and triethylammonium salts. High reaction rates are achieved with imidazolium and triethylammonium salts provided that their alkyl "tail" is ≥C 8. Fast and complete phase separation, and good retention of the metal in the aqueous phase could be achieved with an octyl "tail". Imidazolium salts were found to give the highest rate enhancement. The nature of the anion showed a moderate influence on the reaction. Evidence suggests that the additive can act as weak surfactant allowing emulsions to be formed and broken by simply switching the stirring on and off.
- Desset, Simon L.,Reader, Simon W.,Cole-Hamilton, David J.
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experimental part
p. 630 - 637
(2010/04/29)
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- Antibiofilm activities of 1-alkyl-3-methylimidazolium chloride ionic liquids
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Microbial biofilms are ubiquitous in nature and represent the predominant mode of growth of microorganisms. A general characteristic of biofilm communities is that they tend to exhibit significant tolerance to antimicrobial challenge compared with planktonic bacteria of the same species The antibiofilm activity of a series of 1-alkyl-3-methylimidazolium chloride ionic liquids has been evaluated against a panel of clinically significant microbial pathogens, including MRSA. A comparison of antimicrobial activity against planktonic bacteria and established biofilms is presented. In general, these ionic liquids possess potent, broad spectrum antibiofilm activity.
- Carson, Louise,Chau, Peter K. W.,Earle, Martyn J.,Gilea, Manuela A.,Gilmore, Brendan F.,Gorman, Sean P.,McCann, Maureen T.,Seddon, Kenneth R.
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experimental part
p. 492 - 497
(2010/04/22)
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- Physical properties of binary and ternary mixtures of ethyl acetate, ethanol, and 1-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide at 298.15 K
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Densities, viscosities, and refractive indices for binary and ternary mixtures of ethanol, ethyl acetate, and l-octyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide have been determined at 298.15 K and atmospheric pressure. Excess molar volumes, and viscosity and molar refraction changes of mixing have been calculated from the measured physical properties. These changes of mixing have been adequately fitted to the Redlieh - Kister polynomial equation. The adjustable parameters and the standard deviations between experimental and calculated values are reported.
- Andreatta, Alfonsina E.,Arce, Alberto,Rodil, Eva,Soto, Ana
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experimental part
p. 1022 - 1028
(2010/04/26)
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- Improved 1-butene/isobutane alkylation with acidic ionic liquids and tunable acid/ionic liquid mixtures
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A new process for 1-butene/isobutane alkylation to yield C 8-alkylates is described using binary mixtures of certain acidic imidazolium ionic liquids (ILs) and strong acids such as sulfuric or trifluoromethanesulfonic (triflic) acid. Equivalent or better conversion (>95%), C8-alkylates selectivity (>70%) and trimethylpentane/ dimethylhexane selectivity (TMP/DMH > 7) were achieved with the IL/acid mixtures over the pure acids themselves. Six types of substituted 3-methyl-imidazolium ionic liquids were investigated, wherein acidity is imparted via either the cation with sulfonic acid groups or the anion (hydrogen sulfate) or both. Long-term studies up to 30+ recycles indicate that the catalyst stability was increased by sometimes greater than 30+% with the IL/acid mixtures over the pure acid. The ionic liquid is believed to tune the acidity, solubility, and interfacial properties, resulting in these enhanced results. In addition, this concept could also be applicable to Friedel-Crafts alkylation, acylation chemistries, or other acid-catalyzed reactions.
- Tang, Shengwei,Scurto, Aaron M.,Subramaniam, Bala
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experimental part
p. 243 - 250
(2011/05/07)
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- Phase diagram data for several salt + salt aqueous biphasic systems at 298.15 K
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Phase diagrams corresponding to aqueous biphasic systems of salt (the organic ionic liquid of salts [C4min]Cl, [C6mim]Cl, and [C8mim]Cl) + salt (K3PO4, K2CO 3) + water were deter
- Deng, Yuefeng,Chen, Ji,Zhang, Dongli
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p. 1332 - 1335
(2008/03/13)
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- Dynamic viscosities of a series of 1-alkyl-3-methylimidazolium chloride ionic liquids and their binary mixtures with water at several temperatures
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Dynamic viscosities, densities, and refractive indices have been measured from T = 298.15 K to T = 343.15 K for 1-hexyl-3-methylimidazolium chloride, [C6mim][Cl], and 1-methyl-3-octylimidazolium chloride, [C 8mim]-[Cl]. Dynamic viscosities and densities have been determined over the whole composition range for water + [C6mim][Cl] and water + [C8mim][Cl] at T = (298.15, 313.15, 328.15, and 343.15) K and 0.1 MPa of pressure. Excess molar volumes and viscosity deviations for the binary systems at the above-mentioned temperatures were fitted to a Redlich-Kister equation to determine the fitting parameters and the root mean square deviations. Densities and viscosities of water + 1-butyl-3-methylimidazolium chloride, [C4mim][Cl], at T= (298.15, 313.15, 328.15, and 343.15) K and 0.1 MPa of pressure have been measured, and apparent molar volumes were determined.
- Gomez, Elena,Gonzalez, Begona,Dominguez, Angeles,Tojo, Emilia,Tojo, Jose
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p. 696 - 701
(2007/10/03)
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- Dicyanoaurate(I) salts with 1-alkyl-3-methylimidazolium: Luminescent properties and room-temperature liquid forming
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Room-temperature ionic liquids containing dicyanoaurate(I) anions were prepared utilizing 1-alkyl-3-methylimidazolium cations, and display luminescence possibly due to the oligomerization of the significant fraction of Au(CN) 2 anions in the li
- Yoshida, Yukihiro,Fujii, Junichi,Saito, Gunzi,Hiramatsu, Takaaki,Sato, Naoki
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p. 724 - 727
(2007/10/03)
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- Determination of thermal diffusivities, thermal conductivities, and sound speeds of room-temperature ionic liquids by the transient grating technique
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We report measurements of thermal diffusivity of several room-temperature ionic liquids (RTILs) using the transient grating method. Measurements are carried out using ionic liquids with small concentrations of an inert dye that is excited by the 532 nm output of a Nd:YAG laser in a grating with a fringe spacings of (92 and 104) μm. The experiments give thermal diffusivities from which thermal conductivities can be determined, sound speeds, and acoustic damping parameters for seven ionic liquids. In this study, we have used combinations of the cation 1-butyl-3-methylimidazolium ([BMIm]+) with the anions tetrafluoroborate ([BF4]-), hexafluorophosphate ([PF6]-), and bis(trifluoromethylsulfonyl)imide ([Tf2N]-) and combinations of the anion [Tf2N]- with the cations 1-ethyl-3-methylimidazolium ([EMIm]+), 1-pentyl-3-methylimidazolium ([PMIm]+), 1-hexyl-3-methylimidazolium ([HMIm]+), and 1-octyl-3-methylimidazolium ([OMIm]+) to determine the effect of anion and cation on the thermophysical properties of the RTILs. Results obtained indicate that the anion exerts a strong influence not only on the sound speed but also on the thermal diffusivity and acoustic damping of the RTILs. For RTILs with the same cation [BMIm]+, changing the anion from [BF 4]- to either [PF6]- or [Tf 2N]- leads to decreases in the sound speed, thermal diffusivity, and thermal conductivity. The size of the cation, however, does not significantly influence the sound speed or the thermal diffusivity of the RTILs.
- Frez, Clifford,Diebold, Gerald J.,Tran, Chieu D.,Yu, Shaofang
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p. 1250 - 1255
(2007/10/03)
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- The HF/BF3-catalysed reaction of substituted benzenes with carbon monoxide
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The HF/BF3-catalysed reactions of phenol and anisole as well as substituted benzenes with CO were investigated as possible routes to commercially important aldehydes. The results confirmed that HF and BF 3 are required in (at least) stoichiometric amounts for effective formylation with CO. With the aim of effecting truly catalytic reaction conditions, the formylation reactions were carried out in ionic liquids. It was shown that phenol is a good substrate for formylation in certain ionic liquids. Georg Thieme Verlag Stuttgart.
- Willemse, J. Alexander,Bezuidenhoudt, Barend C. B.,Holzapfel, Cedric W.
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p. 2543 - 2550
(2008/02/04)
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- Organic salt conditioner, organic salt-containing composition, and uses thereof
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The present invention relates to the use of, and a composition containing, at least one non-polymeric organic salt with a melting point of less than 60° C. These organic salts may be imidazolium, pyrazolium, pyridinium, pyrimidinium or tetraalkylphosphonium salts. The inventinon composition may be used for washing (cleaning) and/or conditioning keratin materials, and especially the hair.
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- Continuous Flow Hydroformylation of Alkenes in Supercritical Fluid-Ionic Liquid Biphasic Systems
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A process for the hydroformylation of relatively low volatility alkenes (demonstrated for 1-dodecene) in a continuous flow system is described. The catalyst is dissolved in an ionic liquid while the substrate and gaseous reagents are transported into the reactor dissolved in supercritical CO 2, which simultaneously acts as a transport vector for aldehyde products. Decompression of the fluid mixture downstream yields products which are free of both reaction solvent and catalyst. The use of rhodium complexes of triaryl phosphites leads to ligand degradation through reaction of the ionic liquid with water and subsequent attack of the released HF on the phosphite. Sodium salts of sulfonated phosphines are insufficiently soluble in the ionic liquids to obtain acceptable rates, but replacing the sodium by a cation similar to that derived from the ionic liquid, allows good solubility and activity to be obtained. The nature of the ionic liquid is very important in achieving high rates, with 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)amides giving the best activity if the alkyl chain is at least C8. Catalyst turnover frequencies as high as 500 h -1 have been observed, with the better rates at higher substrate flow rates. Rhodium leaching into the product stream can be as low as 0.012 ppm, except at low partial pressures of CO/H2, when it is significantly higher. Oxygen impurities in the CO2 feed can lead to oxidation of the phosphine giving higher rates, lower selectivities to the linear aldehyde, increased alkene isomerization and greater leaching of rhodium. However, it is found that under certain process conditions, the supercritical fluid-ionic liquid (SCF-IL) system can be operated continuously for several weeks without any visible sign of catalyst degradation. Comparisons with commercial hydroformylation processes are provided.
- Webb, Paul B.,Sellin, Murielle F.,Kunene, Thulani E.,Williamson, Sylvia,Slawin, Alexandra M. Z.,Cole-Hamilton, David J.
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p. 15577 - 15588
(2007/10/03)
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- Solvent-free sonochemical preparation of ionic liquids.
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[reaction: see text] An ultrasound-assisted preparation of a series of ambient-temperature ionic liquids, 1-alkyl-3-methylimidazolium (AMIM) halides, which proceeds via efficient reaction of 1-methyl imidazole with alkyl halides/terminal dihalides under solvent-free conditions, is described.
- Namboodiri, Vasudevan V,Varma, Rajender S
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p. 3161 - 3163
(2007/10/03)
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