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

• Bulletin of the Korean Chemical Society
• /
• v.33 no.8
• /
• pp.2724-2730
• /
• 2012

A new heterogeneous acidic catalyst was successfully prepared by impregnation of silica (Aerosil 300) by an acidic ionic liquid, named 1-(4-sulfonic acid)butylpyridinium hydrogen sulfate [$PYC_4SO_3H$][$HSO_4$], and characterized using FT-IR spectroscopy, the $N_2$ adsorption/desorption analysis (BET), thermal analysis (TG/DTG), and X-ray diffraction (XRD) techniques. The amount of loaded acidic ionic liquid on Aerosil 300 support was determined by acid-base titration. This new solid acidic supported heterogeneous catalyst exhibits excellent activity in the synthesis of 2-aryl-2,3-dihydroquinazolin-4(1H)-ones by cyclocondensation reaction of 2-aminobenzamide with aromatic aldehydes under solvent-free conditions and the desired products were obtained in very short reaction times with high yields. This catalyst has the advantages of an easy catalyst separation from the reaction medium and lower problems of corrosion. Recycling of the catalyst and avoidance of using harmful organic solvent are other advantages of this simple procedure.

• Bulletin of the Korean Chemical Society
• /
• v.33 no.7
• /
• pp.2140-2144
• /
• 2012

A polymer support immobilized acidic ionic liquid was prepared by copolymerization of 3-vinyl-1-(4-sulfonic acid)butylimidazolium hydrogen sulfate with styrene in the presence of benzoyl peroxide and its primary application as a solid acidic heterogeneous catalyst to the synthesis of Hantzsch 1,4-dihydropyridines through a one-pot three-component reaction of aromatic aldehydes, ethyl acetoacetate and ammonium acetate was investigated. The results showed that this heterogeneous catalyst has high catalytic activity and the desired products were obtained in good to high yields. Moreover, the catalyst was found to be reusable and a considerable catalytic activity still could be achieved after third run.

• Korean Chemical Engineering Research
• /
• v.51 no.3
• /
• pp.347-351
• /
• 2013

The preparation of glycerol carbonate (GC) from urea through carbonylation with renewable glycerol was investigated by using ionic liquid catalysts. It was found that quaternary ammonium salt and imidazolium salt ionic liquids with a shorter alkyl chain length and higher nucleophilic anion showed better catalytic performance. The effects of reaction temperature, reaction time and degree of vacuum on the reactivity of TBAC catalyst ware discussed. Zinc chloride ($ZnCl_2$) was used as co-catalyst with the ionic liquid catalyst. The mixed catalyst showed a synergy effect on the glycerol conversion and GC yield probably due to the acid-base properties of the catalysts.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.1
• /
• pp.225-230
• /
• 2013

A new heteropolyanion-based ionic ($[Hmim]_5PMo_{10}V_2O_{40}$) was synthesized by the reaction of molybdovanadophosphoric acid ($H_5PMo_{10}O_{40}$) with N-methylimidazole. [$[Hmim]_5PMo_{10}V_2O_{40}$ showed a high catalytic activity in the oxidative desulfurization of sulfur-containing compounds in 1-methylimidazolium tetrafluoroborate ($[Hmim]BF_4$) ionic liquid using 30% aqueous $H_2O_2$ as the oxidant. The catalytic system was of high activity, simplified workup and flexible recyclability. The catalytic oxidation reactivity of sulfur-containing compounds decreased in the order dibenzothiophene (DBT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT) > benzothiophene (BT). The influences of various parameters including reaction time (t) and temperature (T), catalyst dosage, and oxidant to sulfur molar ratio n(O)/n(S) on the desulfurization of model oil were investigated in details. 99.1% of DBT conversion in the model oil was achieved at atmospheric pressure under the optimal conditions: n(O)/n(S) = 4:1, $60^{\circ}C$, 100 min and molar ratio of catalyst to sulfur of 0.062. The ionic liquid can be recycled six times without significant decrease in activity.

• Korean Chemical Engineering Research
• /
• v.51 no.1
• /
• pp.106-110
• /
• 2013

In this work, we investigated 20 kinds of ionic liquids as catalyst during the hydrolysis of Saccharina japonica. Three kinds of ionic liquid, 1-ethyl-3-methylimidazolium tetrafluoroborate, n-butyl-4-methylpyridinium tetrafluoroborate, and n-methylmorpholine [$HSO_4$], are selected, and then investigated the effect of reaction temperature, catalyst amount and reaction time. The hydrolysis of S. japonica was increased by the increasing of reaction temperature and ionic liquid amount. Also, the hydrolysis presented the linear increase by the increasing of reaction time. After 90 min of reaction, the concentrations of reducing sugar of 1-ethyl-3-methylimidazolium tetrafluoroborate, n-butyl-4-methylpyridinium tetrafluoroborate, and n-methylmorpholine [$HSO_4$] are reached to 6.2 g/L, 6.4 g/L and 6.0 g/L, respectively. As an overall result, we obtained the possibility of hydrolysis of marine biomass using ionic liquids.

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

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2011.11a
• /
• pp.645-648
• /
• 2011

Hydrazine which has been used as monopropellant shows high performance, but because of its high toxicity research for new green propellant that could replace hydrazine is going on. Ionic liquid propellant that is one of the green propellant has lower toxicity, higher specific impulse, and higher density than hydrazine. To design the thruster which use Hydroxylamine Nitrate (HAN), one of ionic liquid propellant, as a propellant, a quantity of catalyst for full decomposition of a propellant is needed. In this study, reference point for HAN thruster design could be suggested through a design of a small scale thruster which used HAN propellant, and propellant decomposition capability evaluation with characteristic velocity efficiency.

• Korean Chemical Engineering Research
• /
• v.48 no.5
• /
• pp.621-626
• /
• 2010

In this study, imidazole-based ionic liquid on polystyrene was prepared and its catalytic performance in the cycloaddition of $CO_2$ with allyl glycidyl ether(AGE) to produce allyl glycidyl carbonate was investigated. The ionic liquid was generated on the polystyrene-based polymer through the immobilization of imidazole. The prepared catalyst was characterized using a number of instrumental analysis including EA, FT-IR, TGA and SEM. The immobilized ionic liquid showed very good catalytic activity for the cycloaddition of $CO_2$ with AGE, having 80% of AGE conversion with over 96% of the carbonate selectivity at $120^{\circ}C$ under 1.48 MPa $CO_2$ pressure. The immobilized ionic liquid can be used for the reaction up to four consecutive runs without significant loss of its catalytic activity.

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