Entry | Catalyst | Conditions | Time (mins) | Yield (%) | Ref. |
1 | Dowex-50 W | Solvent free/100˚C | 90 | 78 | [10] |
2 | Molecular iodine | Solvent free/90˚C | 20 | 90 | [11] |
3 | Heteropolyacid | Solvent free/100˚C | 30 | 89 | [12] |
4 | Fe3O4@SiO2-Imid-PMAn | Solvent free/110˚C | 90 | 95 | [13] |
5 | Montmorillonite K-10 | Solvent free/MW | 04 | 92 | [14] |
6 | [Et3N?SO3H]Cl | Solvent free/120˚C | 30 | 96 | [15] |
7 | [H-NMP][HSO4] | Solvent free/110˚C | 12 | 94 | [16] |
8 | SiO2?Pr?SO3H | Solvent free/125˚C | 20 | 98 | [17] |
9 | HBF4-SiO2 | Solvent free/120˚C | 90 | 92 | [18] |
10 | NSPV PHS | Ultrasound irradiation | 05 | 95 | [19] |
11 | [BMIm][BF4] | Solvent free/80˚C | 300 | 98 | [20] |
12 | L-Pyrrolidine-2-carboxylic acid sulfate(LPCAS) | Solvent free/100˚C | 06 | 95 | This work |