Table 1.
Lists and physical-chemical properties of DES prepared in this study.
| No. | Component A | Component B | Abbreviations | Molar ratio (mol/mol) |
Viscosity (mPa·s, 30% water, 25 °C) |
|---|---|---|---|---|---|
| 1 | Choline chloride | Citric acid | ChCl-CA | 2:1 | 246.68 ± 1.38 |
| 2 | Choline chloride | Oxalic acid | ChCl-OA | 1:1 | 149.16 ± 3.26 |
| 3 | Choline chloride | Levulinic acid | ChCl-LevA | 1:2 | 270.11 ± 6.87 |
| 4 | Choline chloride | Malic acid | ChCl-MaA | 1:2 | 140.73 ± 1.95 |
| 5 | Choline chloride | Acetic acid | ChCl-AA | 1:3 | 222.18 ± 1.77 |
| 6 | Betaine | Citric acid | Bet-CA | 1:2 | 117.07 ± 3.11 |
| 7 | Betaine | Oxalic acid | Bet-OA | 1:2 | 119.85 ± 6.69 |
| 8 | Betaine | Levulinic acid | Bet-LevA | 1:1 | 271.17 ± 5.59 |
| 9 | Betaine | Malic acid | Bet-MaA | 1:2 | 226.19 ± 2.18 |
| 10 | Betaine | Acetic acid | Bet-AA | 1:3 | 259.35 ± 4.95 |
| 11 | l-Proline | Citric acid | Pro-CA | 1:2 | 285.07 ± 2.16 |
| 12 | l-Proline | Oxalic acid | Pro-OA | 1:2 | – |
| 13 | l-Proline | Levulinic acid | Pro-LevA | 1:2 | 207.65 ± 8.87 |
| 14 | l-Proline | Malic acid | Pro-MaA | 1:2 | 153.39 ± 8.90 |
| 15 | l-Proline | Acetic acid | Pro-AA | 1:2 | – |