Ultrasound-assisted solvent-free synthesis of lactic acid esters in novel SO3H-functionalized Brønsted acidic ionic liquids.
Mild and efficient Fischer esterification reactions of lactic acid with a variety of straight chain aliphatic alcohols, cyclohexanol and benzyl alcohol were successfully performed using two novel Brønsted acidic ionic liquids that bear an aromatic sulfonic acid group on the imidazolium or pyridinium cation under ultrasound irradiation. These reactions carried out smoothly with good to excellent conversion rate (78-96%) and satisfactory yields (73-92%) in shorter reaction time (4-6h) at room temperature when the amount of ionic liquids was 20 mol%. These ionic liquids could be recovered readily and recycled five times without any significant loss in their catalytic activity.
Li
Xinzhong
X
Department of Chemistry and Chemical Engineering, Minjiang University, Fuzhou 350108, China. bails_wl@126.com
Lin
Qi
Q
Ma
Liang
L
D000143:Acids / Q000737:chemistry / Q000528:radiation effects; D004952:Esters / Q000737:chemistry / Q000528:radiation effects; D052578:Ionic Liquids / Q000737:chemistry* / Q000528:radiation effects*; D019344:Lactic Acid / Q000138:chemical synthesis* / Q000528:radiation effects*; D012997:Solvents / Q000737:chemistry / Q000528:radiation effects; D013010:Sonication; D013431:Sulfates / Q000737:chemistry* / Q000528:radiation effects*
D000143:Acids; D004952:Esters; D052578:Ionic Liquids; D012997:Solvents; D013431:Sulfates; D019344:Lactic Acid