1024035-97-9Relevant academic research and scientific papers
One-pot synthesis of 3-substituted indole derivatives using moisture stable, reusable, and task specific ionic liquid catalysts
Ravindran, Anaswara,Kore, Rajkumar,Srivastava, Rajendra
, p. 129 - 135 (2013/02/25)
Moisture stable Broensted acidic (BIL) and Lewis acidic ionic liquid catalysts have been synthesized and their catalytic activities have been examined in the synthesis of biologically important indole-3-derivatives. Catalytic activities of these ionic liquid catalysts have been investigated for some important catalytic reactions such as three component coupling reaction of benzaldehyde, N-methylaniline and indole and Michael addition reaction of indole with β- nitrostyrene/chalcone/acetyl acetone. In all these reactions, BIL functionalized with sulfonic acid is found to be the best task specific catalyst. BILs are inexpensive and easy to synthesize, and can be separated easily and reused for three cycles without significant loss in catalytic activity. Catalyst offers several attractive features such as low cost, high catalytic activity/selectivity and recyclability.
Hydration of alkynes using Br?nsted acidic ionic liquids in the absence of Nobel metal catalyst/H2SO4
Kore, Rajkumar,Kumar, T.J. Dhilip,Srivastava, Rajendra
, p. 61 - 70 (2012/08/14)
In this study, a variety of imidazole based sulfonic acid group functionalized Br?nsted acidic ionic liquids (BAILs) were synthesized. BAILs have been successfully developed as task specific ionic liquids for hydration of alkynes under mild conditions to give high yields of ketones as a selective product. Acidity of BAILs was determined using volumetric titration and UV-visible spectroscopic methods. The Hammett acidity order and acid value of BAILs correlate well with the activity order observed for most of the BAILs in the hydration reaction of phenylacetylene. Theoretical studies demonstrate that hydrogen bonding plays a key role in tuning the acidity of BAILs. Density function theory calculations are also able to explain the difference in activity observed in these BAILs. The activity of ionic liquids was theoretically studied by computing the activation energy for the hydration reaction. Recycling experiments suggest that these novel BAILs can be reused without significant loss in activity. BAILs are simple and easy to prepare and exhibit excellent activity toward the hydration of a variety of alkynes to ketones. Moreover, the reaction involving BAILs does not involve heavy metal catalysts or H 2SO4. Novel BAILs offer several attractive features such as sustainable synthetic route, low cost, moisture stability, high yields, and recyclability.
Synthesis and applications of novel imidazole and benzimidazole based sulfonic acid group functionalized Broensted acidic ionic liquid catalysts
Kore, Rajkumar,Srivastava, Rajendra
experimental part, p. 117 - 126 (2011/10/05)
In this study, a variety of imidazole/benzimidazole based sulfonic acid group functionalized Broensted acidic ionic liquids (BAILs) were synthesized. Catalytic activities of BAILs were assessed using multi-component coupling reactions. Catalytic activities of BAILs were high when compared with those of solid acid catalysts such as H-ZSM-5, H-BETA, and sulfonic acid functionalized SBA-15 catalysts. The Hammett acidity order determined from UV-visible spectroscopy of BAILs is consistent with their activity order observed in acid-catalyzed reactions. Theoretical studies demonstrate that the hydrogen bonding plays a key role in tuning the acidity of BAILs. Recycling experiments suggest that these novel BAILs can be reused without significant loss in catalytic activity. Novel BAILs offer several attractive features such as low cost, high catalytic activity, and recyclability.
Synthesis and applications of highly efficient, reusable, sulfonic acid group functionalized Broensted acidic ionic liquid catalysts
Kore, Rajkumar,Srivastava, Rajendra
scheme or table, p. 1420 - 1424 (2012/07/31)
A variety of sulfonic acid group functionalized Broensted acidic ionic liquids (BAILs) catalysts were synthesized. Catalytic activities of BAILs were assessed using condensation and esterification reactions. Catalytic activities of BAILs were high when compared with H-ZSM-5, H-BETA, sulfonic acid functionalized SBA-15 catalyst. The Hammett acidity order determined from UV-visible spectroscopy of BAILs is consistent with their activity order observed in acid-catalyzed reactions. Recycling experiments suggests that these novel BAILs can be reused without significant loss in catalytic activity. Novel BAILs offers several attractive features such as low cost, high catalytic activity and recyclability.
Ultrasound-assisted solvent-free synthesis of lactic acid esters in novel SO3H-functionalized Br?nsted acidic ionic liquids
Li, Xinzhong,Lin, Qi,Ma, Liang
, p. 752 - 755 (2011/10/08)
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 Br?nsted 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 (4-6 h) 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.
