Table 7. Effect of the Solvent and HMF Concentration on HMF Conversion and DFF Yield with Fe(NO3)3/NaNO2/TEMPO Catalyst System Conditionsa.
| entry | solvent | solvent amount (mL) | conv. HMF (%) | yield DFF (%) | select.b (%) |
|---|---|---|---|---|---|
| 1 | 55 | 51 | 93 | ||
| 2 | H2O | 5 | 3 | 3 | 100 |
| 3 | EtOAc | 5 | 100 | 98 | 98 |
| 4 | DCE | 5 | 100 | 93 | 93 |
| 5 | MeCN | 5 | 100 | 94 | 94 |
| 6 | MeCN | 2 | 100 | 96 | 96 |
| 7 | MeCN | 1 | 80 | 77 | 96 |
a
Reaction conditions: HMF (1 mmol, 126 mg), Fe(NO3)3·9H2O (0.05 mmol, 20 mg), TEMPO (0.05 mmol, 7.8 mg), NaNO2 (0.05 mmol, 3.4 mg), 50 °C, 10 h, and oxygen balloon; the conversion and yield were determined by HPLC. Conv. = conversion. Select. = selectivity.
b
S (DFF) = yield (DFF)/conversion (HMF).