Table 3. Effect of the Solvent and HMF Concentration on HMF Conversion and DFF Yield with Fe(NO3)3/TEMPO Catalyst Systema.
| entry | solvent | solvent amount (mL) | conv. HMF (%) | yield DFF (%) | select.b (%) |
|---|---|---|---|---|---|
| 1 | EtOAc | 2 | 100 | 57 | 57 |
| 2 | DCE | 2 | 100 | 64 | 64 |
| 3 | AcOH | 1 | 62 | 61 | 98 |
| 4 | AcOH | 2 | 100 | 95 | 95 |
| 5 | AcOH | 5 | 58 | 52 | 90 |
a
Reaction conditions: HMF (1 mmol, 126 mg), Fe(NO3)3·9H2O (0.05 mmol), TEMPO (0.05 mmol, 7.8 mg), 50 °C, 5 h, and oxygen balloon; the conversion and yield were determined by HPLC. Conv. = conversion. Select. = selectivity.
b
S (DFF) = yield (DFF)/conversion (HMF).