• Bulletin of the Korean Chemical Society
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• v.26 no.9
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• pp.1321-1330
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• 2005

The use of ionic liquids as reaction media can confer many advantages upon catalytic reactions over reactions in organic solvents. In ionic liquids, catalysts having polar or ionic character can easily be immobilized without additional structural modification and thus the ionic solutions containing the catalyst can easily be separated from the reagents and reaction products, and then, be reused. More interestingly, switching from an organic solvent to an ionic liquid often results in a significant improvement in catalytic performance (e.g., rate acceleration, (enantio)selectivity improvement and an increase in catalyst stability). In this review, some recent interesting results which can nicely demonstrate these positive “ionic liquid effect” on catalysis are discussed.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.153-157
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• 2016

In this study, three different metal-containing ionic liquid catalysts were prepared by metal insertion and characterized by various physicochemical analytic methods. The catalytic performance of the metal containing ionic liquids in the cycloaddition of $CO_2$ with propylene oxide (PO) to produce propylene carbonate (PC) was investigated under the solvent free condition. The order of approximate rate constants ($K_{app}$) for the metal containing ionic liquid catalysts was $(MeIm)_2ZnCl_2$, > $(MeIm)_2FeCl_2$ > $(MeIm)_2CuCl_2$. These results are in accord with the experimentally obtained activity order of the different metal containing ionic liquid catalysts.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.3 no.2
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• pp.116-121
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• 2017

To overcome the low reactivity and solubility of alkali metal fluorides (MFs), various types of phase transfer catalysts (PTCs) have been developed over the last decades. However, since the fluoride activated by such PTC sometimes has a strong basicity, it may cause various side reactions such as elimination reaction or hydroxylation reaction in the nucleophilic fluorination reaction. Also, they may cause separation problems in the compound purification process. In recent advanced study, various PTCs have been developed to solve these problem of conventional catalyst. In this review, we would like to introduce three kinds of novel multifunctional organic catalysts such as bis-tert-alcohol-functionalized crown-6-calix[4]arene (BACCA), easy separable pyrene-tagged ionic liquid (PIL) by reduced graphene oxide (rGO), and tri-tert-butanolamine organic catalyst.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.1925-1926
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• 2007

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.286-290
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• 2007

The esterification efficiency of several ionic liquids has been investigated to determine the feasibility for the conversion of free fatty acids to alkylester. Five ionic liquid catalysts having strong acidity, BPC[$AlCl_3$], BMIM[$Bf_4$], BMIM[$Pf_6$], EMIM[$Ntf_2$], BMIM[Otf], have been employed in this work. BPC[$AlCl_3$] has the highest esterification efficiency among the ionic liquid catalysts. Over 90% conversion efficiency has been achieved in the esterification of the simulated used cooking oil by BPC[$AlCl_3$] with two hours reaction time. Since BPC[$AlCl_3$] has several advantages such as high esterification activity, ease of separation from reaction mixture and reusability after treatment procedure, it will be a promising catalyst for the conversion of free fatty acids to esters in waste fats.

• Journal of the Korean Chemical Society
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• v.55 no.4
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• pp.685-690
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• 2011

Novel acidic ionic liquids, 1-(${\omega}$-sulfonicacid)propyl-3-methylimidazolium bromide ([$HSO_3$pmim]Br)and 1-(${\omega}$-sulfonicacid)butyl-3-methylimidazolium bromide ([$HSO_3$bmim]Br), were prepared and used as brominating agents, catalysts and solvents in the synthesis of 1,7-dibromoheptane, respectively. 1,7-dibromoheptan with a yield of 95% was obtained at $100^{\circ}C$ for 2 h by simple phase separation. The acidic ionic liquid [$HSO_3$pmim]Br was recycled for 5 times and the yield of 1,7-dibromoheptane did not decrease remarkably, which indicates that catalysts still maintain good selectivity and activity after recycling. The structure of the acidic ionic liquid [$HSO_3$pmim]Br was characterized with IR, and it was found that [$HSO_3$pmim]Br had stronger acidity than other ionic liquid.

• Applied Chemistry for Engineering
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• v.27 no.2
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• pp.190-194
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• 2016

Tricyclopentadiene (TCPD) is one of the important precursors for making tetrahydrotricyclopentadiene, which is well known as a next-generation fuel with high energy density. In this study, TCPD was obtained by polymerization reaction of dicyclopentadiene (DCPD) using an ionic liquid (IL) supported mesoporous silica catalysts. ILs were supported to two kinds of mesoporous silica catalysts with different pore sizes such as MCM-41 and SBA-15. Four different ILs were supported to mesoporous silicas using anionic precursors such as CuCl or $FeCl_3$ and cationic precursors such as triethylamine hydrochloride or 1-butyl-3-methylimidazolium chloride. We proved that IL supported mesoporous silicas showed better catalytic performance than those of using non-supported prestine IL in the aspect of TCPD yield and DCPD conversion. Among four kinds of IL supported mesoporous silica catalysts, CuCl-based IL supported MCM-41 system showed the highest TCPD yield.

• Bulletin of the Korean Chemical Society
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• v.33 no.10
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• pp.3373-3377
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• 2012

A series of polystyrene-supported 1-(propyl-3-sulfonate)-3-methyl-imidazolium hydrosulfate acidic ionic liquid (PS-$[SO_3H-PMIM][HSO_4]$) catalysts were prepared and tested for mononitration of simple aromatics compounds with nitric acid. It was found that the reactivity of the catalysts increased with increasing $[SO_3H-PMIM][HSO_4]$ content. The para-selectivity was not only related to the $[SO_3H-PMIM][HSO_4]$ content but also the substituent groups in aromatics. A reaction mechanism of nitration over this new catalyst was proposed. The catalytic activity of this catalyst decreased slightly after fifth runs in the synthesis of nitrotoluene.

• Applied Chemistry for Engineering
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• v.25 no.3
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• pp.249-253
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• 2014

Palladium on carbon catalysts for hexafluoropropylene hydrogenation were prepared using imidazolium hexafluorophosphate with various cation parts. The morphology of palladium was relatively affected by the cation parts of the ionic liquid. With increasing alkyl chains of the ionic liquid cation, the shape of palladium particle changed from spherical to cylindrical due to the effect of steric stabilization. After calcination at $500^{\circ}C$, all catalysts possessed the comparable crystal structure. Under the identical reaction conditions, the catalyst prepared using the ionic liquid with hexyl chain in cation parts showed the most effective reactivity.

• Journal of the Korean Applied Science and Technology
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• v.25 no.4
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• pp.469-476
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• 2008

The synthesis of cyclic carbonate from butyl glycidyl ether (BGE) and carbon dioxide was performed in the presence of three different types of ionic liquid : quarternary ammonium salt, alkyl pyridinium salt, and alkylimidazolium salt. Ionic liquids of different alkyl groups ($C_3$, $C_4$, $C_6$ and $C_8$) and anions ($Cl^-$, $Br^-$ and $I^-$) were used for the reaction which was carried out in a batch autoclave reactor at $60{\sim}120^{\circ}C$. The catalytic activity was increased with increasing alkyl chain length in the order of $C_3$ < $C_4$ < $C_6$. But the ionic liquid with longer alkyl chain length ($C_8$) decreased the conversion of BGE because it is too bulky to form an intermediate with BGE. For the counter anion of the ionic liquid catalysts, the BGE conversion decreased in the order $Cl^-$ > $Br^-$ > $I^-$.