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1.
Reverse atom transfer radical polymerization (ATRP) of methyl methacrylate (MMA) employing 2,2-azobisisobutyronitrile (AIBN)/CuCl2/bipyridine(bipy) as the initiating system was approached at 80 °C in two ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate ([C4mim][BF4]) and 1-dodecyl-3-methylimidazolium tetrafluoroborate ([C12mim][BF4]), respectively. The polymerization in [C12mim][BF4] proceeded in a well-controlled manner as evidenced by kinetic studies, end group analysis, chain extension, and block copolymerization results, but not in [C4mim][BF4] presumably due to poor solubility of PMMA in it. The kinetic study of reverse ATRP of MMA in recycled [C12mim][BF4] suggested that this ionic liquid could be re-used as reaction solvent after simple purification, without affecting the living nature of polymerization. 相似文献
2.
Atom transfer radical polymerization using activators regenerated by electron transfer (ARGET ATRP) of acrylonitrile with FeBr3 and isophthalic acid (IA) as catalyst and ligand, ascorbic acid (VC) as reducing agent, and ethyl 2‐bromoisobutyrate as initiator was approached for the first time in the presence of air in 1‐dodecyl‐3‐methylimidazolium tetrafluoroborate ([C12mim][BF4]), 1‐octyl‐3‐methylimidazolium tetrafluoroborate ([C8mim][BF4]), and 1‐butyl‐3‐methylimidazolium tetrafluoroborate ([C4mim][BF4]). The rate of polymerization in [C12mim][BF4] was considerably faster than in [C8mim][BF4] and [C4mim][BF4]. With an increase of VC concentration, both the monomer conversion and the molecular weight distribution showed a trend of increase. Polyacrylonitrile (PAN) with higher molecular weight at 166,250 and broader distribution at 1.34 was successfully prepared with PAN as macroinitiator via ARGET ATRP in [C12mim][BF4] in the presence of air. The resultant polyacrylonitrile fibers were obtained with the fineness at 1.15 dtex and the tenacity at 6.24 cN dtex?1. Additionally, it was shown that [C12mim][BF4] could be recycled and reused after simple purification and had no effect on the living nature of polymerization. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
3.
JinKyoon Park Pentlavalli Sreekanth B.Moon Kim 《Advanced Synthesis \u0026amp; Catalysis》2004,346(1):49-52
Various imidazolium ionic liquids such as [Bmim]PF6, [Bmim]SbF6, [Bmim]OTf and [Bmim]BF4 were screened for recycling an organic catalyst [(5S)‐5‐benzyl‐2,2,3‐trimethylimidazolidin‐4‐one ( 1 )] for asymmetric Diels–Alder reactions. Good yields and enantioselectivies (up to 85% yield and 93% ee) were obtained from reactions in [Bmim]PF6 or [Bmim]SbF6. However, reactions in [Bmim]OTf or [Bmim]BF4 gave racemic products in low yields. Isolation of the products by simple extraction using diethyl ether allowed recycling of the ionic liquid containing the immobilized catalyst in subsequent reactions without significant decrease of yields and enantioselectivities. 相似文献
4.
《分离科学与技术》2012,47(5):663-669
Both hydrophibic [C8mim][PF6] and [C4mim]Cl/(K2CO3, K2HPO4 or K3PO4) aqueous biphasic system (ABS) were employed for the enrichment of aromatic compounds including nitrobenzene, 4-nitrophenol, phenol and aniline from aqueous solutions. In [C8mim][PF6] enrichment system, the distribution ratio (D) of nitrobenzene and aniline increase with the increasing of pH values of aqueous phase from 2 to 8, but there is no obvious change for 4-nitrophenol and phenol. And the D values of the aromatic compounds decrease with the phase ratio change from 1/5 to 1/30 (IL phase volume/aqueous phase volume). In [C4mim]Cl/(K2CO3, K2HPO4 or K3PO4), the distribution ratio increase with the increasing of the salts concentrations. The distribution ratio order in [C8mim][PF6] and [C4mim]Cl/kosmotropic salt ABS is nitrobenzene > phenol > aniline > 4-nitrophenol. It is expected that these results are promising for the removal of the aromatic compounds from water, especially for sample enrichment in analytical science. 相似文献
5.
Haixia Shan Zaijun Li Ming Li Guoxia Ren Yinjun Fang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2008,83(6):886-891
BACKGROUND: Enzymes may exhibit enhanced activity, stability and selectivity in ionic liquids, depending on the properties of the liquid. The physical–chemical properties of ionic liquids, however, may be modified by altering the anion or cation in the ionic liquid. This feature is a key factor for realizing successful reactions. In this work, a new ionic liquid, 1‐isobutyl‐3‐methylimidazolium hexafluorophosphate (abbreviated as [i‐C4mim][PF6]), was synthesized and investigated as a novel medium for the transesterification reaction of 2‐phenylethanol with vinyl acetate catalyzed by pseudomonas capaci lipase. As contrasts, the reaction was also carried out in two reference solvents; the isomeric ionic liquid [i‐C4mim][PF6], 1‐butyl‐3‐methylimidazolium hexafluorophosphate (abbreviated as [C4mim][PF6]), and hexanes. RESULTS: As reaction medium, [i‐C4mim][PF6] was best among the three solvents. The initial reaction rate, the equilibrium conversion of 2‐phenylethanol and the half‐lifetime of the lipase in [i‐C4mim][PF6] medium were about 1.5, 1.2 and 3‐fold that obtained in [C4mim][PF6] medium, respectively. The lipase in [i‐C4mim][PF6] medium was recycled 10 times without substantial diminution in activity. CONCLUSION: The ionic liquid [i‐C4mim][PF6] has good biocompatibility, and can be used widely as green media in various biocatalysis reactions to improve the activity and stability of enzymes. Besides hydrophobicity and nucleophilicity, the spatial configuration of ionic liquids is also considered a key factor effecting the behaviour of the enzyme in ionic liquids. Copyright © 2008 Society of Chemical Industry 相似文献
6.
Shuai Xu Chongpin Huang Jie Zhang Jia Liu Biaohua Chen 《Korean Journal of Chemical Engineering》2009,26(4):985-989
Peroxidation of alkylaromatics is the key step in the synthesis of phenols. Different imidazolium ionic liquids were investigated
for the oxidation of cumene. The selectivity of cumene hydroperoxide (CHP) increased with different ionic liquids in the order
[C4mim]Cl<[C4mim]Br<[C4mim]BF4<[C4mim]OH. This finding could be interpreted as being due to the partial decomposition of CHP by the acidic proton of the imidazolium
cation. Thus [C4mim]OH was chosen as the catalyst for the oxidation of 1,3-diisopropylbenzene to corresponding hydroperoxides and its derivatives.
The catalytic performance of [C4mim]OH was also better than that of the traditional catalyst NaOH. Furthermore, the effects of the operating variables were
investigated and the mechanism was discussed. 相似文献
7.
Ionic liquids (ILs) functionalized solvent impregnated resins (SIRs) were prepared using IL modified Merrified resin as the polymeric supports by impregnation of extractant for extraction of Sc(III). The ILs modified Merrifield resin were prepared via covalent anchoring of imidazolium salts onto Merrifield resin. The polymeric supports with imidazolium chloride group (RCl) and imidazolium hexafluorophosphate group (RPF6) were characterized by FTIR, TGA, and elemental analysis. It was found that RCl and RPF6 had tunable hydrophilicity and hydrophobicity, different acid stability, and swelling behaviors in solvents. The effect of Cyanex 923 extractant or [C8mim][PF6] IL impregnated on RCl and RPF6 were studied. The results showed Cyanex 923 and [C8mim][PF6] exhibited stronger affinity to RPF6 than to RCl. RPF6 with Cyanex 923 was found to be effective in Sc(III) extraction. The extraction mechanisms of SIRs containing RPF6 and Cyanex 923 with or without [C8mim][PF6] were cation exchange and neutral complexation, respectively. [C8mim][PF6] acted as an extraction media and was involved in the cation exchanged extraction reaction. Sc(III) can be selectively separated from Tm(III), Yb(III), and Lu(III) by the SIRs. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
8.
《分离科学与技术》2012,47(8):2090-2102
Abstract Liquid–liquid extraction with imidazolium based ionic liquids ([C4mim][PF6], [C6mim][PF6], and [C8mim][PF6]) is proposed for the separation of furfural or 5-methylfurfural from aqueous solution. Factors affecting the extraction of furfural or 5-methylfurfural have been studied. It was shown that the extraction equilibria can be achieved within 30 min and the process was less affected by the factors such as volume ratio and feed concentration. The partition coefficients of furfural and 5-methylfurfural decreased with increasing temperature. [C6mim][PF6] was found to have the best extraction ability among the three ionic liquids studied. Presence of small amount of NaCl or Na2SO4 in the aqueous phase results in the considerable increase in the partition coefficients of furfural because of the competitive hydration of the salts with furfural. A thermodynamic study revealed that the extraction process was driven mainly by hydrophobic interactions. Further experimental results indicated that furfural can be separated selectively from aqueous furfural/acetic acid mixtures. 相似文献
9.
Optimization of Enzymatic Synthesis of Tricaprylin in Ionic Liquids by Response Surface Methodology 总被引:1,自引:0,他引:1
Qiuyue Pan Liping Yang Xianghe Meng 《Journal of the American Oil Chemists' Society》2013,90(4):501-509
Ten 1,3‐dialkylimidazolium‐based ionic liquids (ILs) have been investigated as media for the enzymatic synthesis of tricaprylin, in comparison with the conventional organic solvent hexane. The results suggested that the esterification activity of Novozym 435 was higher than Lypozyme RM IM in all the ILs assayed. Novozym 435 showed higher catalytic activity in ILs with anions Tf2N? and PF6? than in BF4? and hexane. FTIR analysis of the secondary structure of the lipase indicated that a smaller decrease of the α‐helix was observed in [C4MIM] Tf2N and [C4MIM] PF6 than [C4MIM] BF4 and hexane, indicating that the anions of ILs might be a key factor for the activity of lipase in ILs. Process parameters (amount of lipase, caprylic acid/glycerol molar ratio, temperature and their interactive effects) were optimized in 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([C4MIM]PF6) using Novozym 435 by response surface methodology. When the reactions were performed with the lipase amount of 6.1 % substrate mass at a caprylic acid/glycerol molar ratio of 4.5:1 and 66.7 °C, a higher yield was reached up to 92.4 %. 相似文献
10.
Hao-Yu Shen Li-Yan Ying Hai-Liang Jiang Zaher M. A. Judeh 《International journal of molecular sciences》2007,8(6):505-512
The selective oxidation of alcohols with molecular oxygen was efficiently completed in high conversion and selectivity using copper-bisisoquinoline-based catalysts under mild reaction condition. The effects of various parameters such as reaction temperature, reaction time, oxidant, ligands, etc, were studied. Solvent effect has been as well studied in ionic liquids [bmim]PF6, [omim]BF4 and [hmim]BF4, comparing to traditional volatile organic solvent. The use of ionic liquids was found to enhance the catalytic properties of the catalysts used. 相似文献
11.
The reverse atom transfer radical polymerization (RATRP) technique using FeCl3/iminodiacetic acid (IMA) complex as a catalyst was applied to the living radical polymerization of acrylonitrile (AN). A hexa-substituted ethane thermal initiator, diethyl 2,3-dicyano-2,3-diphenylsuccinate (DCDPS), was firstly used as the initiator in this iron-based RATRP system. The polymerization in N,N-dimethylformamide not only shows the best control of molecular weight and its distribution but also provides rather rapid reaction rate with the ratio of [AN]:[DCDPS]:[FeCl3]:[IMA] at 500:1:2:4. The rate of polymerization increases with increasing the polymerization temperature and the apparent activation energy was calculated to be 49.9 kJ mol−1. The polymers obtained were end-functionalized by chlorine atom, and they were used as macroinitiators to proceed the chain extension polymerization in the presence of FeCl2/IMA catalyst system via a conventional ATRP process. The resultant polyacrylonitrile fibers were obtained with the fineness at 1.16 dtex and the tenacity at 6.01cN dtex−1. 相似文献
12.
Xiaoqi Sun Dongbei Wu Ji Chen Deqian Li 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2007,82(3):267-272
The separation of Sc(III) from Y(III), La(III) and Yb(III) in [C8mim][PF6] containing Cyanex 925 has been investigated, and is reported in this paper. A cation exchange mechanism of Sc(III) in [C8mim][PF6] and Cyanex 925 is proposed by study of the influence of anionic and cationic species on the extraction. The coefficient of the equilibrium equation of Sc(III) was confirmed by slope analysis of log DSc vs log [Cyanex 925], and the loading capacity also confirmed the stoichiometry of Cyanex 925 to Sc(III) was close to 3:1. Infrared data for Cyanex 925 saturated with Sc(III) in [C8mim][PF6] indicated strong interaction between P?O of Cyanex 925 and Sc(III). In addition, the relationship between log DSc and temperature showed that temperature had little influence on the extraction process, and the resulting thermodynamic parameters indicated that an exothermic process was involved. Copyright © 2007 Society of Chemical Industry 相似文献
13.
Alkenes undergo smooth cyclopropanation with ethyl diazoacetate using a catalytic amount of rhodium acetate dimer, Rh2(OAc)4, immobilized in the air‐ and moisture‐stable 1‐butyl‐3‐methylimidazolium hexafluorophosphate ionic liquid, [bmim]PF6, to afford cyclopropanecarboxylates in excellent yields with high trans‐selectivity. The recovery of the catalyst is facilitated by the hydrophobic nature of [bmim]PF6. The recovered ionic liquid containing Rh2(OAc)4 can be reused for three to five subsequent runs with only a gradual decrease in activity. 相似文献
14.
Abstract We tested dissolution and regeneration of poplar wood using 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) and 1-butyl-3-methylimidazolium acetate ([C4mim]OAc). When 5wt% of poplar sawdust in [C4mim]OAc was stirred at 130°C, 96wt% of added poplar was dissolved in [C4mim]OAc, whereas 25.3wt% of poplar dissolved in [C4mim]Cl at the same reaction condition. Fourier transform infrared spectroscopy (FT-IR) and lignin content analysis revealed that poplar was partially delignified during the dissolution and regeneration processes. X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and microscopy were used to characterize raw poplar sawdust, undissolved poplar, and regenerated wood from the poplar-ionic liquid solution. The direct acetylation of poplar-[C4mim]OAc solution using acetyl chloride was also performed in the absence of any organic solvent. FT-IR analysis of the resulting wood sample revealed the formation of partially delignified acetylated-poplar. 相似文献
15.
The extractive removal of sulfur compounds (S-compounds) from Dongying and Liaohe diesel fuels with [BF4]^--based ionic liquids were systematically investigated. The results show that the absorption capacity of an ionic liquid for the S-compounds in diesel fuels relies on its structure and its size. In the case of the two examined diesel fuels, both elongating the cation tail length and increasing the mass ratio of ionic liquid/diesel fuel promote the desulfurization ability of the examined ionic liquids. The results also show that imidazolium-based ionic liquids display higher extraction efficiencies than pyridinium-based ionic liquids, presumably owing to the fact that the rings of the S-compounds are similar to the imidazolium head ring. With the 1 : 1 mass ratio of ionic liquid/diesel fuel, the rates of the first desulfurization of Dongying and Liaohe diesel fuels using [C8mim][BF4] amount to 29.96% and 39.76%, suggesting that [C8mim][BF4] is a promising extractant for desulfurization of these diesel fuels. 相似文献
16.
Eun-Ha Lee So-Wan Cha Manju Mamparambath Dharma Youngson Choe Ji-Yun Ahn Dae-Won Park 《Korean Journal of Chemical Engineering》2007,24(3):547-550
The cycloaddition of carbon dioxide to epichlorohydrin was performed without any solvent in the presence of ionic liquid as
catalyst. 1-Alkyl-3-methyl imidazolium salts of different alkyl group (C2, C4, C6, C8) and anions (Cl−, BF4−, Br−, PF6−) were used for this reaction carried out in a batch autoclave reactor. The conversion of epichlorohydrin was affected by
the structure of the imidazolium salt ionic liquid; the one with the cation of longer alkyl chain length and with more nucleophilic
anion showed better reactivity. The conversion of epichlorohydrin increased as the temperature increased from 60°C to 140°C.
It also increased with increasing carbon dioxide pressure probably due to the increase of the absorption of carbon dioxide
into the mixture of epichlorohydrin and the ionic liquid. Zinc bromide was also tested for its use as a cocatalyst in this
reaction.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献
17.
The reactivity of palladacycle dimeric complexes with substituted triarylphosphito ligands P(OR)3 (R = Ph, m-MeC6H4, o-MeC6H4, C6H3-2,4-tBu2) as well as their non-orthometallated analogues PdCl2[P(OR)3]2 was tested in a copper-free Sonogashira reaction with iodobenzene and phenylacetylene as substrates and imidazolium ionic liquids as the reaction medium. The ionic liquids [bmim][PF6], [bmim][BF4] and [emim][SO4Et] were chosen. The palladium complexes studied showed high activity, and the yield of diphenylacetylene ranged from 31 to 98% in 1 h. The best results were obtained in [bmim][PF6] for PdCl2[P(O-m-MeC6H4)3]2 (84%) and for orthopalladated dimer with the same phosphite (98%). 相似文献
18.
Chen Hou Chunnuan Ji Rongjun Qu Chunhua Wang Changmei Sun Wenying Zhou Mengmeng Yu 《应用聚合物科学杂志》2007,105(3):1575-1580
A hexa‐substituted ethane thermal iniferter, diethyl‐2,3‐dicyano‐2,3‐di(p‐tolyl) succinate (DCDTS), was firstly used as the initiator in the reverse atom transfer radical polymerization (RATRP) of acrylonitrile. FeCl3 coordinated by isophthalic acid (IA) was used as the catalyst in this system. The polymerization in N,N‐dimethylformamide not only shows the best control of molecular weight and its distribution but also provides rather rapid reaction rate with the ratio of [AN] : [DCDTS] : [FeCl3] : [IA] at 500 : 1 : 2 : 4. The polymers obtained were end‐functionalized by chlorine atom, and they were used as macroinitiators to proceed the chain extension polymerization in the presence of FeCl2/IA catalyst system via a conventional ATRP process and polyacrylonitrile obtained was with Mn = 39,260, PDI = 1.25. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007 相似文献
19.
《分离科学与技术》2012,47(15):2372-2380
The partitioning behavior of model acidic (bovine serum albumin, BSA), basic (hen egg white lysozyme, LYS), and neutral (horse heart myoglobin, MYO) proteins in ionic liquid-based aqueous biphasic systems containing Reactive Red-120 dye has been reported. This study found that partition coefficients of the proteins depended on their chemical structures, pH of the aqueous phase, temperature, and composition of the aqueous biphasic system. It was found that partition coefficients of proteins in aqueous biphasic system containing RR-120 were in the order of LYS > MYO > BSA. Recovery of the hydrophilic ionic liquid, [C4mim]Br, was achieved by using hydrophobic ionic liquid, [C4mim]PF6. 相似文献
20.
《分离科学与技术》2012,47(8):1208-1214
The FeCl3-containing Lewis-acidic ionic liquids (ILs) [C6mim]Cl/FeCl3(1:1.5), [C6mim]Cl/FeCl3(1:2), [C8mim]Cl/FeCl3(1:1.5), and [C8mim]Cl/FeCl3(1:2) were used as extractants for desulfurization of model fuel and gasoline fuel, respectively. The results demonstrate that these ILs are effective for the removal of sulfur compounds from model fuel under different mass ratio of IL to model fuel (1:1, 1:3, 1:5, 1:10) at 25°C. The extractive performance of ILs increased as the molar ratio of FeCl3 to [Cnmim]Cl(n = 6, 8) varied from 1:1 to 1:2. The selectivity of sulfur compounds by extraction process followed the order of dibenzothiophene (DBT)>benzothiophene (BT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT). The sulfur removal of gasoline fuel containing sulfur content of 440.3 ppmw could be up to 85.8%; that is to say that the sulfur content of gasoline fuel varied from 440.3 ppmw to 62.4 ppmw after one extraction stage. Moreover, the [C6mim]Cl/FeCl3(1:2) can be recycled for at least 4 times with a little decrease in the desulfurization activity. 相似文献