Preparation of Novel Ionic Liquids and Their Applications in Brominating Reaction

새로운 산성 이온용액인1-( ${\omega}$ -sulfonicacid)propyl-3-methylimidazolium bromide ([ $HSO_3$ pmim]Br)과 1-( ${\omega}$ -sulfonicacid)-butyl-3-methylimidazolium bromide([ $HSO_3$ bmim]Br)을 제조하였다. 이 화합물들을 브롬화 시약 및 용매로 사용하여 $100^{\circ}C$ , 2시간 반응시켰으며, 간단히 상분리에 의해 1,7-dibromoheptane을 95% 수율로 합성하였다. 이 산성 이온용액을 5회 재사용하였으나 수율 감소가 관찰되지 않았다. 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.